1
|
De Leon VS, Chen J, McCollum G, Park JW, Louzada ES, Setamou M, Kunta M. Diversity of ' Candidatus Liberibacter asiaticus' Strains in Texas Revealed by Prophage Sequence Analyses. PLANT DISEASE 2024:PDIS09231994SR. [PMID: 38252141 DOI: 10.1094/pdis-09-23-1994-sr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
Prophages/phages are important components of the genome of 'Candidatus Liberibacter asiaticus' (CLas), an unculturable alphaproteobacterium associated with citrus huanglongbing (HLB) disease. Phage variations have significant contributions to CLas strain diversity research, which provide critical information for HLB management. In this study, prophage variations among selected CLas strains from southern Texas were studied. The CLas strains were collected from three different CLas inhabitant environments: citrus leaf, citrus root, and Asian citrus psyllid (ACP), the vector of CLas. Regardless of the different habitats and time span, more than 80% of CLas strains consistently had both Type 1 and Type 2 prophages, the same prophage type profile as in CLas strains from Florida but different to those reported in California and China. Further studies were performed on prophage type diversity. Analyses on Type 1-specific PCR amplicon sequences (encoding an endolysin protein) revealed the presence of two groups: Type 1-A, clustered around prophage SC1 originating from Florida, and Type 1-B, clustered with prophage P-SGCA5-1 originating in California. Type 1-B strains were mostly from ACP of nearby citrus orchards. On the other hand, analyses on Type 2-specific PCR amplicon sequences (encoding a putative hypothetical protein) showed a single group clustering around prophage SC2 originated from Florida, although a different Type 2 prophage has been reported in California. The presence of two distinct Type 1 prophage groups suggested the possibility of two different CLas introductions in southern Texas. The results from this study provide an initial baseline of information on genomic and population diversity of CLas in Texas.
Collapse
Affiliation(s)
| | - Jianchi Chen
- San Joaquín Valley Agricultural Sciences Center, USDA-ARS, Parlier, CA 93648
| | - Greg McCollum
- Horticultural Research Laboratory, USDA-ARS, Fort Pierce, FL 34945
| | - Jong-Won Park
- Texas A&M University Kingsville Citrus Center, Weslaco, TX 78599
| | | | - Mamoudou Setamou
- Texas A&M University Kingsville Citrus Center, Weslaco, TX 78599
| | | |
Collapse
|
2
|
Li Y, Ma R, Gao C, Li Z, Zheng Y, Fang F, Wang C, Li G, Du X, Xu C, Xu M, Liu R, Deng X, Zheng Z. Integrated bacterial transcriptome and host metabolome analysis reveals insights into " Candidatus Liberibacter asiaticus" population dynamics in the fruit pith of three citrus cultivars with different tolerance. Microbiol Spectr 2024; 12:e0405223. [PMID: 38440971 PMCID: PMC10986616 DOI: 10.1128/spectrum.04052-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 01/22/2024] [Indexed: 03/06/2024] Open
Abstract
"Candidatus Liberibacter asiaticus" (CLas), the causal agent of citrus Huanglongbing (HLB), is able to multiply to a high abundance in citrus fruit pith. However, little is known about the biological processes and phytochemical substances that are vital for CLas colonization and growth in fruit pith. In this study, CLas-infected fruit pith of three citrus cultivars ("Shatangju" mandarin, "Guanxi" pomelo, and "Shatian" pomelo) exhibiting different tolerance to CLas were collected and used for dual RNA-Seq and untargeted metabolome analysis. Comparative transcriptome analysis found that the activation of the CLas noncyclic TCA pathway and pathogenic-related effectors could contribute to the colonization and growth of CLas in fruit pith. The pre-established Type 2 prophage in the CLas genome and the induction of its CRISPR/cas system could enhance the phage resistance of CLas and, in turn, facilitate CLas population growth in fruit pith. CLas infection caused the accumulation of amino acids that were correlated with tolerance to CLas. The accumulation of most sugars and organic acids in CLas-infected fruit pith, which could be due to the phloem blockage caused by CLas infection, was thought to be beneficial for CLas growth in localized phloem tissue. The higher levels of flavonoids and terpenoids in the fruit pith of CLas-tolerant cultivars, particularly those known for their antimicrobial properties, could hinder the growth of CLas. This study advances our understanding of CLas multiplication in fruit pith and offers novel insight into metabolites that could be responsible for tolerance to CLas or essential to CLas population growth.IMPORTANCECitrus Huanglongbing (HLB, also called citrus greening disease) is a highly destructive disease currently threatening citrus production worldwide. HLB is caused by an unculturable bacterial pathogen, "Candidatus Liberibacter asiaticus" (CLas). However, the mechanism of CLas colonization and growth in citrus hosts is poorly understood. In this study, we utilized the fruit pith tissue, which was able to maintain the CLas at a high abundance, as the materials for dual RNA-Seq and untargeted metabolome analysis, aiming to reveal the biological processes and phytochemical substances that are vital for CLas colonization and growth. We provided a genome-wide CLas transcriptome landscape in the fruit pith of three citrus cultivars with different tolerance and identified the important genes/pathways that contribute to CLas colonization and growth in the fruit pith. Metabolome profiling identified the key metabolites, which were mainly affected by CLas infection and influenced the population dynamic of CLas in fruit pith.
Collapse
Affiliation(s)
- Yun Li
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Ruifeng Ma
- Institute of Fruit Tree Research, Meizhou Academy of Agriculture and Forestry Sciences, Meizhou, Guangdong, China
| | - Chenying Gao
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Ziyi Li
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Yongqin Zheng
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Fang Fang
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Cheng Wang
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Guohua Li
- Institute of Fruit Tree Research, Meizhou Academy of Agriculture and Forestry Sciences, Meizhou, Guangdong, China
| | - Xiaozhen Du
- Institute of Fruit Tree Research, Meizhou Academy of Agriculture and Forestry Sciences, Meizhou, Guangdong, China
| | - Changbao Xu
- College of Horticulture, South China Agricultural University, Guangzhou, Guangdong, China
| | - Meirong Xu
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Rui Liu
- Institute of Fruit Tree Research, Meizhou Academy of Agriculture and Forestry Sciences, Meizhou, Guangdong, China
| | - Xiaoling Deng
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Zheng Zheng
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| |
Collapse
|
3
|
Hyde JR, Armond T, Herring JA, Hope S, Grose JH, Breakwell DP, Pickett BE. Diversity and conservation of the genome architecture of phages infecting the Alphaproteobacteria. Microbiol Spectr 2024; 12:e0282723. [PMID: 37991376 PMCID: PMC10783043 DOI: 10.1128/spectrum.02827-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 10/24/2023] [Indexed: 11/23/2023] Open
Abstract
IMPORTANCE This study reports the results of the largest analysis of genome sequences from phages that infect the Alphaproteobacteria class of bacterial hosts. We analyzed over 100 whole genome sequences of phages to construct dotplots, categorize them into genetically distinct clusters, generate a bootstrapped phylogenetic tree, compute protein orthologs, and predict packaging strategies. We determined that the phage sequences primarily cluster by the bacterial host family, phage morphotype, and genome size. We expect that the findings reported in this seminal study will facilitate future analyses that will improve our knowledge of the phages that infect these hosts.
Collapse
Affiliation(s)
- Jonathan R. Hyde
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Thomas Armond
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Jacob A. Herring
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Sandra Hope
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Julianne H. Grose
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Donald P. Breakwell
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Brett E. Pickett
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| |
Collapse
|
4
|
Xu L, Mo K, Ran D, Ma J, Zhang L, Sun Y, Long Q, Jiang G, Zhao X, Zou X. An endolysin gene from Candidatus Liberibacter asiaticus confers dual resistance to huanglongbing and citrus canker. HORTICULTURE RESEARCH 2023; 10:uhad159. [PMID: 37719271 PMCID: PMC10500150 DOI: 10.1093/hr/uhad159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 07/27/2023] [Indexed: 09/19/2023]
Abstract
The most damaging citrus diseases are Huanglongbing (HLB) and citrus canker, which are caused by Candidatus Liberibacter asiaticus (CaLas) and Xanthomonas citri pv. citri (Xcc), respectively. Endolysins from bacteriophages are a possible option for disease resistance in plant breeding. Here, we report improvement of citrus resistance to HLB and citrus canker using the LasLYS1 and LasLYS2 endolysins from CaLas. LasLYS2 demonstrated bactericidal efficacy against several Rhizobiaceae bacteria and Xcc, according to inhibition zone analyses. The two genes, driven by a strong promoter from Cauliflower mosaic virus, 35S, were integrated into Carrizo citrange via Agrobacterium-mediated transformation. More than 2 years of greenhouse testing indicated that LasLYS2 provided substantial and long-lasting resistance to HLB, allowing transgenic plants to retain low CaLas titers and no obvious symptoms while also clearing CaLas from infected plants in the long term. LasLYS2 transgenic plants with improved HLB resistance also showed resistance to Xcc, indicating that LasLYS2 had dual resistance to HLB and citrus canker. A microbiome study of transgenic plants revealed that the endolysins repressed Xanthomonadaceae and Rhizobiaceae populations in roots while increasing Burkholderiaceae and Rhodanobacteraceae populations, which might boost the citrus defense response, according to transcriptome analysis. We also found that Lyz domain 2 is the key bactericidal motif of LasLYS1 and LasLYS2. Four endolysins with potential resistance to HLB and citrus canker were found based on the structures of LasLYS1 and LasLYS2. Overall, the work shed light on the mechanisms of resistance of CaLas-derived endolysins, providing insights for designing endolysins to develop broad-spectrum disease resistance in citrus.
Collapse
Affiliation(s)
- Lanzhen Xu
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing 400712, China
| | - Kaiqing Mo
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing 400712, China
| | - Danlu Ran
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing 400712, China
| | - Juanjuan Ma
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing 400712, China
| | - Lehuan Zhang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing 400712, China
| | - Yijia Sun
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing 400712, China
| | - Qin Long
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing 400712, China
| | - Guojin Jiang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing 400712, China
| | - Xiaochun Zhao
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing 400712, China
| | - Xiuping Zou
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing 400712, China
| |
Collapse
|
5
|
Zheng Y, Zhang J, Li Y, Liu Y, Liang J, Wang C, Fang F, Deng X, Zheng Z. Pathogenicity and Transcriptomic Analyses of Two " Candidatus Liberibacter asiaticus" Strains Harboring Different Types of Phages. Microbiol Spectr 2023; 11:e0075423. [PMID: 37071011 PMCID: PMC10269750 DOI: 10.1128/spectrum.00754-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 03/31/2023] [Indexed: 04/19/2023] Open
Abstract
"Candidatus Liberibacter asiaticus" is one of the putative causal agents of citrus Huanglongbing (HLB), a highly destructive disease threatening the global citrus industry. Several types of phages had been identified in "Ca. Liberibacter asiaticus" strains and found to affect the biology of "Ca. Liberibacter asiaticus." However, little is known about the influence of phages in "Ca. Liberibacter asiaticus" pathogenicity. In this study, two "Ca. Liberibacter asiaticus" strains, PYN and PGD, harboring different types of phages were collected and used for pathogenicity analysis in periwinkle (Catharanthus roseus). Strain PYN carries a type 1 phage (P-YN-1), and PGD harbors a type 2 phage (P-GD-2). Compared to strain PYN, strain PGD exhibited a faster reproduction rate and higher virulence in periwinkle: leaf symptoms appeared earlier, and there was a stronger inhibition in the growth of new flush. Estimation of phage copy numbers by type-specific PCR indicated that there are multiple copies of phage P-YN-1 in strain PYN, while strain PGD carries only a single copy of phage P-GD-2. Genome-wide gene expression profiling revealed the lytic activity of P-YN-1 phage, as evidenced by the unique expression of genes involved in lytic cycle, which may limit the propagation of strain PYN and lead to a delayed infection in periwinkle. However, the activation of genes involved in lysogenic conversion of phage P-GD-1 indicated it could reside within the "Ca. Liberibacter asiaticus" genome as a prophage form in strain PGD. Comparative transcriptome analysis showed that the significant differences in expression of virulence factor genes, including genes associated with pathogenic effectors, transcriptional factors, the Znu transport system, and the heme biosynthesis pathway, could be another major determinant of virulence variation between two "Ca. Liberibacter asiaticus" strains. This study expanded our knowledge of "Ca. Liberibacter asiaticus" pathogenicity and provided new insights into the differences in pathogenicity between "Ca. Liberibacter asiaticus" strains. IMPORTANCE Citrus Huanglongbing (HLB), also called citrus greening disease, is a highly destructive disease threatening citrus production worldwide. "Candidatus Liberibacter asiaticus" is one of the most common putative causal agents of HLB. Phages of "Ca. Liberibacter asiaticus" have recently been identified and found to affect "Ca. Liberibacter asiaticus" biology. Here, we found that "Ca. Liberibacter asiaticus" strains harboring different types of phages (type 1 or type 2) showed different levels of pathogenicity and multiplication patterns in the periwinkle plant (Catharanthus roseus). Transcriptome analysis revealed the possible lytic activity of type 1 phage in a "Ca. Liberibacter asiaticus" strain, which could limit the propagation of "Ca. Liberibacter asiaticus" and lead to the delayed infection in periwinkle. The heterogeneity in the transcriptome profiles, particularly the significant differences in expression of virulence factors genes, could be another major determinant of difference in virulence observed between the two "Ca. Liberibacter asiaticus" strains. These findings improved our understanding of "Ca. Liberibacter asiaticus"-phage interaction and provided insight into "Ca. Liberibacter asiaticus" pathogenicity.
Collapse
Affiliation(s)
- Yongqin Zheng
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, China
| | - Jingxue Zhang
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, China
| | - Yun Li
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, China
| | - Yaoxin Liu
- Horticulture Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, Guangxi, China
| | - Jiayin Liang
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, China
| | - Cheng Wang
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, China
| | - Fang Fang
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, China
| | - Xiaoling Deng
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, China
| | - Zheng Zheng
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, China
| |
Collapse
|
6
|
Du J, Wang Q, Shi H, Zhou C, He J, Wang X. A prophage-encoded effector from "Candidatus Liberibacter asiaticus" targets ASCORBATE PEROXIDASE6 in citrus to facilitate bacterial infection. MOLECULAR PLANT PATHOLOGY 2023; 24:302-316. [PMID: 36692022 PMCID: PMC10013806 DOI: 10.1111/mpp.13296] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 01/03/2023] [Accepted: 01/03/2023] [Indexed: 05/21/2023]
Abstract
Citrus huanglongbing (HLB), associated with the unculturable phloem-limited bacterium "Candidatus Liberibacter asiaticus" (CLas), is the most devastating disease in the citrus industry worldwide. However, the pathogenicity of CLas remains poorly understood. In this study, we show that AGH17488, a secreted protein encoded by the prophage region of the CLas genome, suppresses plant immunity via targeting the host ASCORBATE PEROXIDASE6 (APX6) protein in Nicotiana benthamiana and Citrus sinensis. The transient expression of AGH17488 reduced the chloroplast localization of APX6 and its enzyme activity, inhibited the accumulation of reactive oxygen species (H2 O2 and O2 - ) and the lipid oxidation endproduct malondialdehyde in plants, and promoted the proliferation of Pseudomonas syringae pv. tomato DC3000 and Xanthomonas citri subsp. citri. This study reveals a novel mechanism underlying how CLas uses a prophage-encoded effector, AGH17488, to target a reactive oxygen species accumulation-related gene, APX6, in the host to facilitate its infection.
Collapse
Affiliation(s)
- Jiao Du
- National Citrus Engineering Research CenterCitrus Research Institute, Southwest UniversityChongqingChina
- Fruit Tree and Melon Information Research CenterZhengzhou Fruit Research Institute, Chinese Academy of Agricultural SciencesZhengzhouChina
| | - Qiying Wang
- National Citrus Engineering Research CenterCitrus Research Institute, Southwest UniversityChongqingChina
| | - Hongwei Shi
- National Citrus Engineering Research CenterCitrus Research Institute, Southwest UniversityChongqingChina
| | - Changyong Zhou
- National Citrus Engineering Research CenterCitrus Research Institute, Southwest UniversityChongqingChina
| | - Jun He
- National Citrus Engineering Research CenterCitrus Research Institute, Southwest UniversityChongqingChina
| | - Xuefeng Wang
- National Citrus Engineering Research CenterCitrus Research Institute, Southwest UniversityChongqingChina
| |
Collapse
|
7
|
Ghosh D, Kokane S, Savita BK, Kumar P, Sharma AK, Ozcan A, Kokane A, Santra S. Huanglongbing Pandemic: Current Challenges and Emerging Management Strategies. PLANTS (BASEL, SWITZERLAND) 2022; 12:plants12010160. [PMID: 36616289 PMCID: PMC9824665 DOI: 10.3390/plants12010160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/06/2022] [Accepted: 12/07/2022] [Indexed: 05/09/2023]
Abstract
Huanglongbing (HLB, aka citrus greening), one of the most devastating diseases of citrus, has wreaked havoc on the global citrus industry in recent decades. The culprit behind such a gloomy scenario is the phloem-limited bacteria "Candidatus Liberibacter asiaticus" (CLas), which are transmitted via psyllid. To date, there are no effective long-termcommercialized control measures for HLB, making it increasingly difficult to prevent the disease spread. To combat HLB effectively, introduction of multipronged management strategies towards controlling CLas population within the phloem system is deemed necessary. This article presents a comprehensive review of up-to-date scientific information about HLB, including currently available management practices and unprecedented challenges associated with the disease control. Additionally, a triangular disease management approach has been introduced targeting pathogen, host, and vector. Pathogen-targeting approaches include (i) inhibition of important proteins of CLas, (ii) use of the most efficient antimicrobial or immunity-inducing compounds to suppress the growth of CLas, and (iii) use of tools to suppress or kill the CLas. Approaches for targeting the host include (i) improvement of the host immune system, (ii) effective use of transgenic variety to build the host's resistance against CLas, and (iii) induction of systemic acquired resistance. Strategies for targeting the vector include (i) chemical and biological control and (ii) eradication of HLB-affected trees. Finally, a hypothetical model for integrated disease management has been discussed to mitigate the HLB pandemic.
Collapse
Affiliation(s)
- Dilip Ghosh
- Plant Virology Laboratory, ICAR-Central Citrus Research Institute, Nagpur 440033, India
- Correspondence: (D.G.); (A.K.S.); (S.S.)
| | - Sunil Kokane
- Plant Virology Laboratory, ICAR-Central Citrus Research Institute, Nagpur 440033, India
| | - Brajesh Kumar Savita
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Pranav Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, India
| | - Ashwani Kumar Sharma
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, India
- Correspondence: (D.G.); (A.K.S.); (S.S.)
| | - Ali Ozcan
- Vocational School of Technical Sciences, Karamanoglu Mehmetbey University, 70200 Karaman, Turkey
- Scientific and Technological Studies Application and Research Center, Karamanoglu Mehmetbey University, 70200 Karaman, Turkey
| | - Amol Kokane
- Plant Virology Laboratory, ICAR-Central Citrus Research Institute, Nagpur 440033, India
| | - Swadeshmukul Santra
- Departments of Chemistry, Nano Science Technology Center, and Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL 32816, USA
- Correspondence: (D.G.); (A.K.S.); (S.S.)
| |
Collapse
|
8
|
Huang J, Alanís-Martínez I, Kumagai L, Dai Z, Zheng Z, Perez de Leon AA, Chen J, Deng X. Machine learning and analysis of genomic diversity of " Candidatus Liberibacter asiaticus" strains from 20 citrus production states in Mexico. FRONTIERS IN PLANT SCIENCE 2022; 13:1052680. [PMID: 36589083 PMCID: PMC9798433 DOI: 10.3389/fpls.2022.1052680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 11/23/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND Huanglongbing (HLB, yellow shoot disease) is a highly destructive citrus disease associated with a nonculturable bacterium, "Candidatus Liberibacter asiaticus" (CLas), which is transmitted by Asian citrus psyllid (ACP, Diaphorina citri). In Mexico, HLB was first reported in Tizimin, Yucatán, in 2009 and is now endemic in 351 municipalities of 25 states. Understanding the population diversity of CLas is critical for HLB management. Current CLas diversity research is exclusively based on analysis of the bacterial genome, which composed two regions, chromosome (> 1,000 genes) and prophage (about 40 genes). METHODS AND RESULTS In this study, 40 CLas-infected ACP samples from 20 states in Mexico were collected. CLas was detected and confirmed by PCR assays. A prophage gene(terL)-based typing system (TTS) divided the Mexican CLas strains into two groups: Term-G including four strains from Yucatán and Chiapas, as well as strain psy62 from Florida, USA, and Term-A included all other 36 Mexican strains, as well as strain AHCA1 from California, USA. CLas diversity was further evaluated to include all chromosomal and prophage genes assisted by using machine learning (ML) tools to resolve multidimensional data handling issues. A Term-G strain (YTMX) and a Term-A strain (BCSMX) were sequenced and analyzed. The two Mexican genome sequences along with the CLas genome sequences available in GenBank were studied. An unsupervised ML was implemented through principal component analysis (PCA) on average nucleotide identities (ANIs) of CLas whole genome sequences; And a supervised ML was implemented through sparse partial least squares discriminant analysis (sPLS-DA) on single nucleotide polymorphisms (SNPs) of coding genes of CLas guided by the TTS. Two CLas Geno-groups, Geno-group 1 that extended Term-A and Geno-group 2 that extended Term-G, were established. CONCLUSIONS This study concluded that: 1) there were at least two different introductions of CLas into Mexico; 2) CLas strains between Mexico and USA are closely related; and 3) The two Geno-groups provide the basis for future CLas subspecies research.
Collapse
Affiliation(s)
- Jiaquan Huang
- Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China
- Center for Biological Science and Technology, Advanced Institute of Natural Sciences, Beijing Normal University at Zhuhai, Zhuhai, Guangdong, China
| | - Iobana Alanís-Martínez
- National Station of Plant Epidemiology, Quarantine and Sanitation, SENASICA, Queretaro, Mexico
| | - Lucita Kumagai
- Plant Pest Diagnostic Center, California Department of Food and Agriculture, Sacramento, CA, United States
| | - Zehan Dai
- Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China
| | - Zheng Zheng
- Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China
| | - Adalberto A. Perez de Leon
- United States Department of Agriculture-Agricultural Research Service (USDA-ARS), San Joaquín Valley Agricultural Sciences Center, Parlier, CA, United States
| | - Jianchi Chen
- United States Department of Agriculture-Agricultural Research Service (USDA-ARS), San Joaquín Valley Agricultural Sciences Center, Parlier, CA, United States
| | - Xiaoling Deng
- Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China
| |
Collapse
|
9
|
Ibrahim YE, Paredes-Montero JR, Al-Saleh MA, Widyawan A, He R, El Komy MH, Al Dhafer HM, Kitchen N, Gang DR, Brown JK. Characterization of the Asian Citrus Psyllid-‘Candidatus Liberibacter Asiaticus’ Pathosystem in Saudi Arabia Reveals Two Predominant CLas Lineages and One Asian Citrus Psyllid Vector Haplotype. Microorganisms 2022; 10:microorganisms10101991. [PMID: 36296267 PMCID: PMC9610752 DOI: 10.3390/microorganisms10101991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/16/2022] [Accepted: 10/01/2022] [Indexed: 11/16/2022] Open
Abstract
In Saudi Arabia (SA), the citrus greening disease is caused by ‘Candidatus Liberibacter asiaticus’ (CLas) transmitted by the Asian citrus psyllid (ACP) Diaphorina citri. The origin and route(s) of the ACP-CLas pathosystem invasion in SA have not been studied. Adult ACP were collected from citrus trees in SA and differentiated by analysis of the mitochondrial cytochrome oxidase I (mtCOI) and nuclear copper transporting protein (atox1) genes. A phylogenetic analysis of the Wolbachia spp. surface protein (wsp) gene was used to identify the ACP-associated Wolbachia spp. A phylogenetic analysis of the atox1 and mtCOI gene sequences revealed one predominant ACP haplotype most closely related to the Indian subcontinent founder populations. The detection and identification of CLas in citrus trees were carried out by polymerase chain reaction (PCR) amplification and sequencing of the 16S rDNA gene. The CLas-integrated prophage genomes were sequenced, annotated, and used to differentiate CLas populations. The ML and ASTRAL trees reconstructed with prophages type 1 and 2 genome sequences, separately and concatenated, resolved two major lineages, CLas-1 and -2. The CLas-1 clade, reported here for the first time, consisted of isolates from SA isolates and Pakistan. The CLas-2 sequences formed two groups, CLas-2-1 and -2-2, previously the ‘Asiatic’ and ‘Floridian’ strains, respectively. Members of CLas-2-1 originated from Southeast Asia, the USA, and other worldwide locations, while CLas-2-2 was identified only in Florida. This study provides the first snapshot into the status of the ACP-CLas pathosystem in SA. In addition, the results provide new insights into the pathosystem coevolution and global invasion histories of two ACP-CLas lineages with a predicted center of origin in South and Southeast Asia, respectively.
Collapse
Affiliation(s)
- Yasser E. Ibrahim
- Plant Protection Department, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia
- Correspondence: author:
| | - Jorge R. Paredes-Montero
- School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, USA
- Department of Biology, Saginaw Valley State University, Saginaw, MI 48710, USA
- Facultad de Ciencias de la Vida, Escuela Superior Politécnica del Litoral, ESPOL, Campus Gustavo Galindo Km 30.5 Vía Perimetral, P.O. Box 09-01-5863, Guayaquil 090902, Ecuador
| | - Mohammed A. Al-Saleh
- Plant Protection Department, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Arya Widyawan
- Plant Protection Department, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Ruifeng He
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Mahmoud H. El Komy
- Plant Protection Department, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Hathal M. Al Dhafer
- Plant Protection Department, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Noel Kitchen
- School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, USA
| | - David R. Gang
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Judith K. Brown
- School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, USA
| |
Collapse
|
10
|
Biological Features and In Planta Transcriptomic Analyses of a Microviridae Phage (CLasMV1) in " Candidatus Liberibacter asiaticus". Int J Mol Sci 2022; 23:ijms231710024. [PMID: 36077424 PMCID: PMC9456138 DOI: 10.3390/ijms231710024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 08/29/2022] [Accepted: 08/30/2022] [Indexed: 11/27/2022] Open
Abstract
“Candidatus Liberibacter asiaticus” (CLas) is the causal agent of citrus Huanglongbing (HLB, also called citrus greening disease), a highly destructive disease threatening citrus production worldwide. A novel Microviridae phage (named CLasMV1) has been found to infect CLas, providing a potential therapeutic strategy for CLas/HLB control. However, little is known about the CLasMV1 biology. In this study, we analyzed the population dynamics of CLasMV1 between the insect vector of CLas, the Asian citrus psyllid (ACP, Diaphorina citri Kuwayama) and the holoparasitic dodder plant (Cuscuta campestris Yunck.); both acquired CLasMV1-infected CLas from an HLB citrus. All CLas-positive dodder samples were CLasMV1-positive, whereas only 32% of CLas-positive ACP samples were identified as CLasMV1-positive. Quantitative analyses showed a similar distribution pattern of CLasMV1 phage and CLas among eight citrus cultivars by presenting at highest abundance in the fruit pith and/or the center axis of the fruit. Transcriptome analyses revealed the possible lytic activity of CLasMV1 on CLas in fruit pith as evidenced by high-level expressions of CLasMV1 genes, and CLas genes related to cell wall biogenesis and remodeling to maintain the CLas cell envelope integrity. The up-regulation of CLas genes were involved in restriction–modification system that could involve possible phage resistance for CLas during CLasMV1 infection. In addition, the regulation of CLas genes involved in cell surface components and Sec pathway by CLasMV1 phage could be beneficial for phage infection. This study expanded our knowledge of CLasMV1 phage that will benefit further CLas phage research and HLB control.
Collapse
|
11
|
Du J, Wang Q, Zeng C, Zhou C, Wang X. A prophage-encoded nonclassical secretory protein of "Candidatus Liberibacter asiaticus" induces a strong immune response in Nicotiana benthamiana and citrus. MOLECULAR PLANT PATHOLOGY 2022; 23:1022-1034. [PMID: 35279937 PMCID: PMC9190977 DOI: 10.1111/mpp.13206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 02/14/2022] [Accepted: 02/23/2022] [Indexed: 05/04/2023]
Abstract
Huanglongbing (HLB), associated with "Candidatus Liberibacter asiaticus" (CLas), is a globally devastating plant disease. The highly reduced genome of CLas encodes a number of secretory proteins. The conserved prophage-encoded protein AGH17470 is herein identified as a nonclassical secretory protein. We confirmed that the N-terminal and C-terminal sequences jointly determine the secretion of AGH17470. The transient expression of AGH17470 protein in Nicotiana benthamiana caused hypersensitive response (HR) cell death in infiltrated leaves and systemically infected leaves as well as the dwarfing of the entire plant, suggesting that AGH17470 is involved in the plant immune response, growth, and development. Overexpression of AGH17470 in N. benthamiana and citrus plants up-regulated the transcription of pathogenesis-related and salicylic acid (SA)-signalling pathway genes and promoted SA accumulation. Furthermore, transient expression of AGH17470 enhanced the resistance of sweet orange to Xanthomonas citri subsp. citri. To our knowledge, AGH17470 is the first prophage-encoded secretory protein demonstrated to elicit an HR and induce a strong plant immune response. The findings have increased our understanding of prophage-encoded secretory protein genes, and the results provide clues as to the plant defence response against CLas.
Collapse
Affiliation(s)
- Jiao Du
- National Citrus Engineering Research CenterCitrus Research InstituteSouthwest UniversityChongqingChina
| | - Qiying Wang
- National Citrus Engineering Research CenterCitrus Research InstituteSouthwest UniversityChongqingChina
| | - Chunhua Zeng
- National Citrus Engineering Research CenterCitrus Research InstituteSouthwest UniversityChongqingChina
| | - Changyong Zhou
- National Citrus Engineering Research CenterCitrus Research InstituteSouthwest UniversityChongqingChina
| | - Xuefeng Wang
- National Citrus Engineering Research CenterCitrus Research InstituteSouthwest UniversityChongqingChina
| |
Collapse
|
12
|
Cui X, Liu K, Huang J, Fu S, Chen Q, Liu X, Zhou C, Wang X. Population Diversity of ' Candidatus Liberibacter asiaticus' and Diaphorina citri in Sichuan: A Case Study for Huanglongbing Monitoring and Interception. PLANT DISEASE 2022; 106:1632-1638. [PMID: 34941368 DOI: 10.1094/pdis-07-21-1539-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Citrus huanglongbing (HLB) is present in 10 provinces in China and is associated with 'Candidatus Liberibacter asiaticus' (CLas), which is transmitted by the Asian citrus psyllid (Diaphorina citri, ACP). To date, HLB and ACP have expanded to Yibin city of Sichuan Province, posing an imminent threat to the citrus belt of the upper and middle reaches of the Yangtze River, an important late-maturing citrus-producing area in China. To understand the epidemiological route of CLas and ACP in newly invaded regions of Sichuan and thereby better establish an HLB interception zone ranging from Leibo to Yibin, we evaluated the molecular variability of 19 CLas draft genomes from citrus or dodder (Cuscuta campestris). They include three type-specific prophage loci, three variable number tandem repeat loci, a miniature inverted-repeat transposable element, and population diversity of 44 ACP mitochondrial genomes. The results indicated that CLas isolates in the newly invaded area (Pingshan) were more diverse than those in the HLB endemic areas (Leibo and Ningnan). Phylogenetic analysis based on mitochondrial genomes demonstrated that ACPs in Leibo, Pingshan, and Xuzhou (rural areas) represent a new mitochondrial group (MG4), distinguished by the three unique single-nucleotide polymorphisms in cox1, nad4, and cytb. However, the ACPs sampled from the urban areas of Cuiping and Xuzhou belonged to the southeastern China group (MG2-1). Altogether, our study revealed multiple sources of ACP and CLas in the HLB interception zone and proposed their transmission route. This study contributes to the formulation of precise HLB prevention and control strategies in the HLB interception zone in Sichuan and could be useful for HLB management efforts in other regions.
Collapse
Affiliation(s)
- Xuejin Cui
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Chongqing 400712, China
| | - Kehong Liu
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Chongqing 400712, China
| | - Jie Huang
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Chongqing 400712, China
| | - Shimin Fu
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Chongqing 400712, China
| | - Qingdong Chen
- Institute of Plant Protection, Sichuan Academy of Agricultural Sciences, Chengdu, Sichuan 610066, China
| | - Xu Liu
- Institute of Plant Protection, Sichuan Academy of Agricultural Sciences, Chengdu, Sichuan 610066, China
| | - Changyong Zhou
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Chongqing 400712, China
| | - Xuefeng Wang
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Chongqing 400712, China
| |
Collapse
|
13
|
Basu S, Huynh L, Zhang S, Rabara R, Nguyen H, Velásquez Guzmán J, Hao G, Miles G, Shi Q, Stover E, Gupta G. Two Liberibacter Proteins Combine to Suppress Critical Innate Immune Defenses in Citrus. FRONTIERS IN PLANT SCIENCE 2022; 13:869178. [PMID: 35586217 PMCID: PMC9108871 DOI: 10.3389/fpls.2022.869178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 04/04/2022] [Indexed: 06/15/2023]
Abstract
We adopted a systems-based approach to determine the role of two Candidatus Liberibacter asiaticus (CLas) proteins, LasP 235 and Effector 3, in Huanglongbing (HLB) pathogenesis. While a published work suggests the involvement of these CLas proteins HLB pathogenesis, the exact structure-based mechanism of their action has not been elucidated. We conducted the following experiments to determine the structure-based mechanisms of action. First, we immunoprecipitated the interacting citrus protein partners of LasP 235 and Effector 3 from the healthy and CLas-infected Hamlin extracts and identified them by Liquid Chromatography with tandem mass spectrometry (LC-MS/MS). Second, we performed a split green fluorescent protein (GFP) assay in tobacco to validate that the interactions observed in vitro are also retained in planta. The notable in planta citrus targets of LasP 235 and Effector 3 include citrus innate immune proteins. Third, in vitro and in planta studies were performed to show that LasP 235 and Effector 3 interact with and inhibit the functions of multiple citrus proteins belonging to the innate immune pathways. These inhibitory interactions led to a high level of reactive oxygen species, blocking of bactericidal lipid transfer protein (LTP), and induction of premature programed cell death (PCD), all of which are beneficial to CLas lifecycle and HLB pathogenesis. Finally, we performed molecular dynamics simulations to visualize the interactions of LasP 235 and Effector 3, respectively, with LTP and Kunitz protease inhibitor. This led to the design of an LTP mimic, which sequestered and blocked LasP 235 and rescued the bactericidal activity of LTP thereby proving that LasP 235 , indeed, participates in HLB pathogenesis.
Collapse
Affiliation(s)
- Supratim Basu
- Biolab, New Mexico Consortium, Los Alamos, NM, United States
| | - Loan Huynh
- Biolab, New Mexico Consortium, Los Alamos, NM, United States
| | - Shujian Zhang
- Biolab, New Mexico Consortium, Los Alamos, NM, United States
| | - Roel Rabara
- Biolab, New Mexico Consortium, Los Alamos, NM, United States
| | - Hau Nguyen
- Biolab, New Mexico Consortium, Los Alamos, NM, United States
| | | | - Guixia Hao
- Horticulture and Breeding, U. S. Horticultural Research Laboratory, Fort Pierce, FL, United States
| | - Godfrey Miles
- Horticulture and Breeding, U. S. Horticultural Research Laboratory, Fort Pierce, FL, United States
| | - Qingchun Shi
- Horticulture and Breeding, U. S. Horticultural Research Laboratory, Fort Pierce, FL, United States
| | - Ed Stover
- Horticulture and Breeding, U. S. Horticultural Research Laboratory, Fort Pierce, FL, United States
| | - Goutam Gupta
- Biolab, New Mexico Consortium, Los Alamos, NM, United States
| |
Collapse
|
14
|
Yang C, Ancona V. An Overview of the Mechanisms Against " Candidatus Liberibacter asiaticus": Virulence Targets, Citrus Defenses, and Microbiome. Front Microbiol 2022; 13:850588. [PMID: 35391740 PMCID: PMC8982080 DOI: 10.3389/fmicb.2022.850588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 02/18/2022] [Indexed: 12/01/2022] Open
Abstract
Citrus Huanglongbing (HLB) or citrus greening, is the most destructive disease for citrus worldwide. It is caused by the psyllid-transmitted, phloem-limited bacteria "Candidatus Liberibacter asiaticus" (CLas). To date, there are still no effective practical strategies for curing citrus HLB. Understanding the mechanisms against CLas can contribute to the development of effective approaches for combatting HLB. However, the unculturable nature of CLas has hindered elucidating mechanisms against CLas. In this review, we summarize the main aspects that contribute to the understanding about the mechanisms against CLas, including (1) CLas virulence targets, focusing on inhibition of virulence genes; (2) activation of citrus host defense genes and metabolites of HLB-tolerant citrus triggered by CLas, and by agents; and (3) we also review the role of citrus microbiome in combatting CLas. Finally, we discuss novel strategies to continue studying mechanisms against CLas and the relationship of above aspects.
Collapse
Affiliation(s)
- Chuanyu Yang
- Department of Agriculture, Agribusiness, and Environmental Sciences, Citrus Center, Texas A&M University-Kingsville, Weslaco, TX, United States
| | - Veronica Ancona
- Department of Agriculture, Agribusiness, and Environmental Sciences, Citrus Center, Texas A&M University-Kingsville, Weslaco, TX, United States
| |
Collapse
|
15
|
Zeng C, Wu H, Cao M, Zhou C, Wang X, Fu S. Integrated Analysis of the miRNAome and Transcriptome Reveals miRNA-mRNA Regulatory Networks in Catharanthus roseus Through Cuscuta campestris-Mediated Infection With " Candidatus Liberibacter asiaticus". Front Microbiol 2022; 13:799819. [PMID: 35308338 PMCID: PMC8928264 DOI: 10.3389/fmicb.2022.799819] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 01/27/2022] [Indexed: 12/30/2022] Open
Abstract
Citrus Huanglongbing (HLB) is the most devastating disease of citrus caused by the Gram-negative phloem-limited bacterium "Candidatus Liberibacter asiaticus" (CLas). It can be transmitted by the Asian citrus psyllid "Diaphorina citri," by grafting, and by the holoparasitic dodder. In this study, the non-natural host periwinkle (Catharanthus roseus) was infected via dodder (Cuscuta campestris) from CLas-infected citrus plants, and the asymptomatic leaves (AS) were subjected to transcriptomic and small-RNA profiling. The results were analyzed together with a transcriptome dataset from the NCBI repository that included leaves for which symptoms had just occurred (S) and yellowing leaves (Y). There were 3,675 differentially expressed genes (DEGs) identified in AS, and 6,390 more DEGs in S and further 2109 DEGs in Y. These DEGs were commonly enriched in photosystem, chloroplast, membrane, oxidation-reduction process, metal/zinc ion binding on GO. A total of 14,974 DEGs and 336 DE miRNAs (30 conserved and 301 novel) were identified. Through weighted gene co-expression network and nested network analyses, two critical nested miRNA-mRNA regulatory networks were identified with four conserved miRNAs. The primary miR164-NAC1 network is potentially involved in plant defense responses against CLas from the early infection stage to symptom development. The secondary network revealed the regulation of secondary metabolism and nutrient homeostasis through miR828-MYB94/miR1134-HSF4 and miR827-ATG8 regulatory networks, respectively. The findings discovered new potential mechanisms in periwinkle-CLas interactions, and its confirmation can be done in citrus-CLas system later on. The advantages of periwinkle plants in facilitating the quick establishment and greater multiplication of CLas, and shortening latency for disease symptom development make it a great surrogate for further studies, which could expedite our understanding of CLas pathogenesis.
Collapse
Affiliation(s)
| | | | | | | | - Xuefeng Wang
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, Chongqing, China
| | - Shimin Fu
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, Chongqing, China
| |
Collapse
|
16
|
Armstrong CM, Zhou L, Luo W, Batuman O, Alabi OJ, Duan Y. Identification of a Chromosomal Deletion Mutation and the Dynamics of Two Major Populations of ' Candidatus Liberibacter asiaticus' in Its Hosts. PHYTOPATHOLOGY 2022; 112:81-88. [PMID: 34645320 DOI: 10.1094/phyto-08-21-0325-fi] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
'Candidatus Liberibacter asiaticus' (Las) is the prominent species of Liberibacter associated with huanglongbing, a devastating disease of citrus worldwide. In this study, we report the identification of an ∼8.3-kb DNA region of the Las genome containing eight putative open reading frames flanked by two inverted repeats, which was not present in the Las str. psy62 genome. Comparisons with other genome sequences established this region as a unique genetic element associated with genome plasticity/instability. Primers specific for both the presence (Las wild type) and absence (Las mutant) of this region were designed to study the population dynamics and host adaptation of the two strains. Las populations with and/or without the wild-type strain were detected and differentiated in >2,300 samples that included psyllids, periwinkle, and several species of citrus. In psyllids, although a mixed population of the wild type and mutant was observed in most samples (88%), the wild-type Las was detected alone at a rate of 11%. In contrast, none of the infected citrus plants were positive for the wild type alone, which harbored either the mutant strain alone (8%) or a mixed population of the mutant and wild type (92%). Furthermore, the dynamics of these two major Las populations varied with different citrus hosts, whereas an in-depth study on grapefruit that did not rapidly succumb to disease revealed that the population of mutant alone increased with time, indicating that the absence of this genetic element is associated with the fitness of Las in planta under the selection pressure of its host.
Collapse
Affiliation(s)
- Cheryl M Armstrong
- Eastern Regional Research Center, U.S. Department of Agriculture-Agricultural Research Service, Wyndmoor, PA
- U.S. Horticultural Research Laboratory, U.S. Department of Agriculture-Agricultural Research Service, Fort Pierce, FL
| | - Lijuan Zhou
- U.S. Horticultural Research Laboratory, U.S. Department of Agriculture-Agricultural Research Service, Fort Pierce, FL
| | - Weiqi Luo
- U.S. Horticultural Research Laboratory, U.S. Department of Agriculture-Agricultural Research Service, Fort Pierce, FL
| | - Ozgur Batuman
- Southwest Florida Research and Education Center, University of Florida, Immokalee, FL 34142
| | - Olufemi J Alabi
- Department of Plant Pathology and Microbiology, Texas A&M AgriLife Research and Extension Center, Weslaco, TX 78596
| | - Yongping Duan
- U.S. Horticultural Research Laboratory, U.S. Department of Agriculture-Agricultural Research Service, Fort Pierce, FL
| |
Collapse
|
17
|
Merfa MV, Naranjo E, Shantharaj D, De La Fuente L. Growth of ' Candidatus Liberibacter asiaticus' in Commercial Grapefruit Juice-Based Media Formulations Reveals Common Cell Density-Dependent Transient Behaviors. PHYTOPATHOLOGY 2022; 112:131-144. [PMID: 34340531 DOI: 10.1094/phyto-06-21-0228-fi] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The phloem-restricted, insect-transmitted bacterium 'Candidatus Liberibacter asiaticus' (CLas) is associated with huanglongbing (HLB), the most devastating disease of citrus worldwide. The inability to culture CLas impairs the understanding of its virulence mechanisms and the development of effective management strategies to control this incurable disease. Previously, our research group used commercial grapefruit juice (GJ) to prolong the viability of CLas in vitro. In the present study, GJ was amended with a wide range of compounds and incubated under different conditions to optimize CLas growth. Remarkably, results showed that CLas growth ratios were inversely proportional to the initial inoculum concentration. This correlation is probably regulated by a cell density-dependent mechanism, because diluting samples between subcultures allowed CLas to resume growth. Moreover, strategies to reduce the cell density of CLas, such as subculturing at short intervals and incubating samples under flow conditions, allowed this bacterium to multiply and reach maximum growth as early as 3 days after inoculation, although no sustained exponential growth was observed under any tested condition. Unfortunately, cultures were only transient, because CLas lost viability over time; nevertheless, we obtained populations of about 105 genome equivalents/ml repeatedly. Finally, we established an ex vivo system to grow CLas within periwinkle calli that could be used to propagate bacterial inoculum in the lab. In this study we determined the influence of a comprehensive set of conditions and compounds on CLas growth in culture. We hope our results will help guide future efforts toward the long-sought goal of culturing CLas axenically.
Collapse
Affiliation(s)
- Marcus V Merfa
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849
| | - Eber Naranjo
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849
| | - Deepak Shantharaj
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849
| | | |
Collapse
|
18
|
Hu B, Rao MJ, Deng X, Pandey SS, Hendrich C, Ding F, Wang N, Xu Q. Molecular signatures between citrus and Candidatus Liberibacter asiaticus. PLoS Pathog 2021; 17:e1010071. [PMID: 34882744 PMCID: PMC8659345 DOI: 10.1371/journal.ppat.1010071] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Citrus Huanglongbing (HLB), also known as citrus greening, is one of the most devastating citrus diseases worldwide. Candidatus Liberibacter asiaticus (CLas) is the most prevalent strain associated with HLB, which is yet to be cultured in vitro. None of the commercial citrus cultivars are resistant to HLB. The pathosystem of Ca. Liberibacter is complex and remains a mystery. In this review, we focus on the recent progress in genomic research on the pathogen, the interaction of host and CLas, and the influence of CLas infection on the transcripts, proteins, and metabolism of the host. We have also focused on the identification of candidate genes for CLas pathogenicity or the improvements of HLB tolerance in citrus. In the end, we propose potentially promising areas for mechanistic studies of CLas pathogenicity, defense regulators, and genetic improvement for HLB tolerance/resistance in the future.
Collapse
Affiliation(s)
- Bin Hu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Ministry of Agriculture), Huazhong Agricultural University, Wuhan, Hubei, China
| | - Muhammad Junaid Rao
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Ministry of Agriculture), Huazhong Agricultural University, Wuhan, Hubei, China
| | - Xiuxin Deng
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Ministry of Agriculture), Huazhong Agricultural University, Wuhan, Hubei, China
| | - Sheo Shankar Pandey
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, Florida, United States of America
| | - Connor Hendrich
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, Florida, United States of America
| | - Fang Ding
- Hubei Key Laboratory of Plant Pathology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, Florida, United States of America
| | - Qiang Xu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Ministry of Agriculture), Huazhong Agricultural University, Wuhan, Hubei, China
| |
Collapse
|
19
|
Zhang L, Li Z, Bao M, Li T, Fang F, Zheng Y, Liu Y, Xu M, Chen J, Deng X, Zheng Z. A Novel Microviridae Phage (CLasMV1) From " Candidatus Liberibacter asiaticus". Front Microbiol 2021; 12:754245. [PMID: 34721359 PMCID: PMC8548822 DOI: 10.3389/fmicb.2021.754245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/07/2021] [Indexed: 11/25/2022] Open
Abstract
“Candidatus Liberibacter asiaticus” (CLas) is an unculturable phloem-limited α-proteobacterium associated with citrus Huanglongbing (HLB; yellow shoot disease). HLB is currently threatening citrus production worldwide. Understanding the CLas biology is critical for HLB management. In this study, a novel single-stranded DNA (ssDNA) phage, CLasMV1, was identified in a CLas strain GDHZ11 from Guangdong Province of China through a metagenomic analysis. The CLasMV1 phage had a circular genome of 8,869 bp with eight open reading frames (ORFs). While six ORFs remain uncharacterized, ORF6 encoded a replication initiation protein (RIP), and ORF8 encoded a major capsid protein (MCP). Based on BLASTp search against GenBank database, amino acid sequences of both MCP and RIP shared similarities (coverage > 50% and identity > 25%) to those of phages in Microviridae, an ssDNA phage family. Phylogenetic analysis revealed that CLasMV1 MCP and RIP sequences were clustered with genes from CLas and “Ca. L. solanacearum” (CLso) genomes and formed a unique phylogenetic lineage, designated as a new subfamily Libervirinae, distinct to other members in Microviridae family. No complete integration form but partial sequence (∼1.9 kb) of CLasMV1 was found in the chromosome of strain GDHZ11. Read-mapping analyses on additional 15 HiSeq data sets of CLas strains showed that eight strains harbored complete CLasMV1 sequence with variations in single-nucleotide polymorphisms (SNPs) and small sequence insertions/deletions (In/Dels). PCR tests using CLasMV1-specific primer sets detected CLasMV1 in 577 out of 1,006 CLas strains (57%) from southern China. This is the first report of Microviridae phage associated with CLas, which expands our understanding of phage diversity in CLas and facilitates current research in HLB.
Collapse
Affiliation(s)
- Ling Zhang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Ziyi Li
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Minli Bao
- China-United States Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, China
| | - Tao Li
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Fang Fang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Yongqin Zheng
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Yaoxin Liu
- Horticulture Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Meirong Xu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Jianchi Chen
- United States Department of Agriculture, San Joaquin Valley Agricultural Sciences Center, Agricultural Research Service, Parlier, CA, United States
| | - Xiaoling Deng
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Zheng Zheng
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| |
Collapse
|
20
|
Tan Y, Wang C, Schneider T, Li H, de Souza RF, Tang X, Swisher Grimm KD, Hsieh TF, Wang X, Li X, Zhang D. Comparative Phylogenomic Analysis Reveals Evolutionary Genomic Changes and Novel Toxin Families in Endophytic Liberibacter Pathogens. Microbiol Spectr 2021; 9:e0050921. [PMID: 34523996 PMCID: PMC8557891 DOI: 10.1128/spectrum.00509-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/10/2021] [Indexed: 01/02/2023] Open
Abstract
Liberibacter pathogens are the causative agents of several severe crop diseases worldwide, including citrus Huanglongbing and potato zebra chip. These bacteria are endophytic and nonculturable, which makes experimental approaches challenging and highlights the need for bioinformatic analysis in advancing our understanding about Liberibacter pathogenesis. Here, we performed an in-depth comparative phylogenomic analysis of the Liberibacter pathogens and their free-living, nonpathogenic, ancestral species, aiming to identify major genomic changes and determinants associated with their evolutionary transitions in living habitats and pathogenicity. Using gene neighborhood analysis and phylogenetic classification, we systematically uncovered, annotated, and classified all prophage loci into four types, including one previously unrecognized group. We showed that these prophages originated through independent gene transfers at different evolutionary stages of Liberibacter and only the SC-type prophage was associated with the emergence of the pathogens. Using ortholog clustering, we vigorously identified two additional sets of genomic genes, which were either lost or gained in the ancestor of the pathogens. Consistent with the habitat change, the lost genes were enriched for biosynthesis of cellular building blocks. Importantly, among the gained genes, we uncovered several previously unrecognized toxins, including new toxins homologous to the EspG/VirA effectors, a YdjM phospholipase toxin, and a secreted endonuclease/exonuclease/phosphatase (EEP) protein. Our results substantially extend the knowledge of the evolutionary events and potential determinants leading to the emergence of endophytic, pathogenic Liberibacter species, which will facilitate the design of functional experiments and the development of new methods for detection and blockage of these pathogens. IMPORTANCELiberibacter pathogens are associated with several severe crop diseases, including citrus Huanglongbing, the most destructive disease to the citrus industry. Currently, no effective cure or treatments are available, and no resistant citrus variety has been found. The fact that these obligate endophytic pathogens are not culturable has made it extremely challenging to experimentally uncover the genes/proteins important to Liberibacter pathogenesis. Further, earlier bioinformatics studies failed to identify key genomic determinants, such as toxins and effector proteins, that underlie the pathogenicity of the bacteria. In this study, an in-depth comparative genomic analysis of Liberibacter pathogens along with their ancestral nonpathogenic species identified the prophage loci and several novel toxins that are evolutionarily associated with the emergence of the pathogens. These results shed new light on the disease mechanism of Liberibacter pathogens and will facilitate the development of new detection and blockage methods targeting the toxins.
Collapse
Affiliation(s)
- Yongjun Tan
- Department of Biology, College of Arts & Sciences, Saint Louis University, St. Louis, Missouri, USA
| | - Cindy Wang
- Department of Biology, College of Arts & Sciences, Saint Louis University, St. Louis, Missouri, USA
| | - Theresa Schneider
- Department of Biology, College of Arts & Sciences, Saint Louis University, St. Louis, Missouri, USA
| | - Huan Li
- Department of Biology, College of Arts & Sciences, Saint Louis University, St. Louis, Missouri, USA
| | - Robson Francisco de Souza
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Xueming Tang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Kylie D. Swisher Grimm
- United States Department of Agriculture—Agricultural Research Service, Temperate Tree Fruit and Vegetable Research Unit, Prosser, Washington, USA
| | - Tzung-Fu Hsieh
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, USA
- Plants for Human Health Institute, North Carolina State University, Kannapolis, North Carolina, USA
| | - Xu Wang
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
- Alabama Agricultural Experiment Station, Auburn University, Auburn, Alabama, USA
- HudsonAlpha Institute for Biotechnology, Huntsville, Alabama, USA
| | - Xu Li
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, USA
- Plants for Human Health Institute, North Carolina State University, Kannapolis, North Carolina, USA
| | - Dapeng Zhang
- Department of Biology, College of Arts & Sciences, Saint Louis University, St. Louis, Missouri, USA
- Bioinformatics and Computational Biology Program, College of Arts & Sciences, Saint Louis University, St. Louis, Missouri, USA
| |
Collapse
|
21
|
Darolt JC, Bento FDMM, Merlin BL, Peña L, Cônsoli FL, Wulff NA. The Genome of " Candidatus Liberibacter asiaticus" Is Highly Transcribed When Infecting the Gut of Diaphorina citri. Front Microbiol 2021; 12:687725. [PMID: 34322103 PMCID: PMC8312247 DOI: 10.3389/fmicb.2021.687725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/04/2021] [Indexed: 11/13/2022] Open
Abstract
The Asian citrus psyllid, Diaphorina citri, is the vector of the bacterium "Candidatus Liberibacter asiaticus" (Las), associated with the devastating, worldwide citrus disease huanglongbing. In order to explore the molecular interactions of this bacterium with D. citri during the vector acquisition process, cDNA libraries were sequenced on an Illumina platform, obtained from the gut of adult psyllids confined in healthy (H) and in Las-infected young shoots (Las) for different periods of times (I = 1/2 days, II = 3/4 days, and III = 5/6 days). In each sampling time, three biological replicates were collected, containing 100 guts each, totaling 18 libraries depleted in ribosomal RNA. Reads were quality-filtered and mapped against the Chinese JXGC Las strain and the Floridian strain UF506 for the analysis of the activity of Las genome and SC1, SC2, and type 3 (P-JXGC-3) prophages of the studied Las strain. Gene activity was considered only if reads of at least two replicates for each acquisition access period mapped against the selected genomes, which resulted in coverages of 44.4, 79.9, and 94.5% of the JXGC predicted coding sequences in Las I, Las II, and Las III, respectively. These genes indicate an active metabolism and increased expression according to the feeding time in the following functional categories: energy production, amino acid metabolism, signal translation, cell wall, and replication and repair of genetic material. Pilins were among the most highly expressed genes regardless of the acquisition time, while only a few genes from cluster I of flagella were not expressed. Furthermore, the prophage region had a greater coverage of reads for SC1 and P-JXGC-3 prophages and low coverage in SC2 and no indication of activity for the lysis cycle. This research presents the first descriptive analysis of Las transcriptome in the initial steps of the D. citri gut colonization, where 95% of Las genes were active.
Collapse
Affiliation(s)
- Josiane Cecília Darolt
- Instituto de Química, Universidade Estadual Paulista “Julio de Mesquita Filho” – UNESP, Araraquara, Brazil
- Departamento de Pesquisa & Desenvolvimento, Fundo de Defesa da Citricultura – Fundecitrus, Araraquara, Brazil
| | - Flavia de Moura Manoel Bento
- Laboratório de Interações em Insetos, Departamento de Entomologia e Acarologia, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, Brazil
| | - Bruna Laís Merlin
- Laboratório de Interações em Insetos, Departamento de Entomologia e Acarologia, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, Brazil
| | - Leandro Peña
- Departamento de Pesquisa & Desenvolvimento, Fundo de Defesa da Citricultura – Fundecitrus, Araraquara, Brazil
- Instituto de Biologia Molecular y Celular de Plantas – Consejo Superior de Investigaciones Científicas, Universidade Politécnica de Valencia, Valencia, Spain
| | - Fernando Luis Cônsoli
- Laboratório de Interações em Insetos, Departamento de Entomologia e Acarologia, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, Brazil
| | - Nelson Arno Wulff
- Instituto de Química, Universidade Estadual Paulista “Julio de Mesquita Filho” – UNESP, Araraquara, Brazil
- Departamento de Pesquisa & Desenvolvimento, Fundo de Defesa da Citricultura – Fundecitrus, Araraquara, Brazil
| |
Collapse
|
22
|
Huang J, Dai Z, Zheng Z, da Silvia PA, Kumagai L, Xiang Q, Chen J, Deng X. Bacteriomic Analyses of Asian Citrus Psyllid and Citrus Samples Infected With " Candidatus Liberibacter asiaticus" in Southern California and Huanglongbing Management Implications. Front Microbiol 2021; 12:683481. [PMID: 34276617 PMCID: PMC8283493 DOI: 10.3389/fmicb.2021.683481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 05/17/2021] [Indexed: 11/13/2022] Open
Abstract
Citrus Huanglongbing (HLB; yellow shoot disease) is associated with an unculturable α-proteobacterium "Candidatus Liberibacter asiaticus" (CLas). HLB was found in southern California in 2012, and the current management strategy is based on suppression of the Asian citrus psyllid (Diaphorina citri) that transmits CLas and removal of confirmed CLas-positive trees. Little is known about Asian citrus psyllid-associated bacteria and citrus-associated bacteria in the HLB system. Such information is important in HLB management, particularly for accurate detection of CLas. Recent advancements in next-generation sequencing technology provide new opportunities to study HLB through genomic DNA sequence analyses (metagenomics). In this study, HLB-related bacteria in Asian citrus psyllid and citrus (represented by leaf midrib tissues) samples from southern California were analyzed. A metagenomic pipeline was developed to serve as a prototype for future bacteriomic research. This pipeline included steps of next-generation sequencing in Illumina platform, de novo assembly of Illumina reads, sequence classification using the Kaiju tool, acquisition of bacterial draft genome sequences, and taxonomic validation and diversity evaluation using average nucleotide identity. The identified bacteria in Asian citrus psyllids and citrus together included Bradyrhizobium, Buchnera, Burkholderia, "Candidatus Profftella armature," "Candidatus Carsonella ruddii," CLas, Mesorhizobium, Paraburkholderia, Pseudomonas, and Wolbachia. The whole genome of a CLas strain recently found in San Bernardino County was sequenced and classified into prophage typing group 1 (PTG-1), one of the five known CLas groups in California. Based on sequence similarity, Bradyrhizobium and Mesorhizobium were identified as possible source that could interfere with CLas detection using the 16S rRNA gene-based PCR commonly used for HLB diagnosis, particularly at low or zero CLas titer situation.
Collapse
Affiliation(s)
- Jiaquan Huang
- Laboratory of Citrus Huanglongbing Research, College of Plant Protection, South China Agricultural University, Guangzhou, China
- San Joaquin Valley Agricultural Sciences Center, Agricultural Research Service, United States Department of Agriculture, Parlier, CA, United States
| | - Zehan Dai
- Laboratory of Citrus Huanglongbing Research, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Zheng Zheng
- Laboratory of Citrus Huanglongbing Research, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | | | - Luci Kumagai
- Plant Pest Diagnostic Center, California Department of Food and Agriculture, Sacramento, CA, United States
| | - Qijun Xiang
- Jerry Dimitman Laboratory, Riverside, CA, United States
| | - Jianchi Chen
- San Joaquin Valley Agricultural Sciences Center, Agricultural Research Service, United States Department of Agriculture, Parlier, CA, United States
| | - Xiaoling Deng
- Laboratory of Citrus Huanglongbing Research, College of Plant Protection, South China Agricultural University, Guangzhou, China
| |
Collapse
|
23
|
Das AK, Chichghare SA, Sharma SK, Kumar JPT, Singh S, Baranwal VK, Kumar A, Nerkar S. Genetic diversity and population structure of 'Candidatus Liberibacter asiaticus' associated with citrus Huanglongbing in India based on the prophage types. World J Microbiol Biotechnol 2021; 37:95. [PMID: 33963452 DOI: 10.1007/s11274-021-03057-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/19/2021] [Indexed: 11/30/2022]
Abstract
Huanglongbing (HLB), also known as 'citrus greening', is an extremely destructive disease of citrus worldwide. HLB is associated with three species of the fastidious proteobacterium, Candidatus Liberibacter asiaticus (CaLas), Ca. L. africanus and Ca. L. americanus with CaLas being the most widely distributed around the world and the only species detected and described so far in India, one of the major global citrus fruit producers. Prophages are highly dynamic components in the bacterial genome and play an important role in intraspecies variations. Three types of prophages, Type 1, Type 2 and Type 3 have been identified and described in CaLas so far. In the present study, 441 CaLas isolates sampled across 18 Indian states were used for prophage typing. Based on detection of three prophage types by PCR, all the eight probable combinations of CaLas prophages were identified, including single Type 1 (26.5%), single Type 2 (18.8%), single Type 3 (1.4%), Type 1 + Type 2 (20.4%), Type 1 + Type 3 (12.5%), Type 2 + Type 3 (4.8%), Type 1 + Type 2 + Type 3 (11.3%) and None type (4.3%). Prophage types were confirmed by PCR amplicon sequencing and subsequent phylogenetic analysis. By discovery of all 3 prophages and based on genetic identity and genetic distance, CaLas populations from eighteen citrus growing states were separated into two major Prophage Typing Groups (PTGs): PTG1 and PTG2. The PTG1 comprised of CaLas from North-West India and PTG2 from rest of the country (North-East, Central and South India), and both major groups were further divided into two (PTG1-A, PTG1-B) and three (PTG2-A, PTG2-B and PTG2-C) subgroups respectively. The findings of CaLas population patterns provide evidence for independent origins of HLB-associated CaLas. CRISPR (clustered regularly interspaced short palindromic repeats) array was also detected in CaLas isolates. This is the first report evaluating the genetic variation of a large population of CaLas bacterium in India using the PCR markers from the prophage regions which would certainly assist the ongoing HLB management efforts in India.
Collapse
Affiliation(s)
- Ashis K Das
- Plant Pathology Lab, ICAR-Central Citrus Research Institute, Amravati Road, Nagpur, 440033, India.
| | - Subham A Chichghare
- Plant Pathology Lab, ICAR-Central Citrus Research Institute, Amravati Road, Nagpur, 440033, India
| | - Susheel K Sharma
- ICAR Research Complex for NEH Region, Manipur Centre, Imphal, 795004, India
| | - J Prasanth Tej Kumar
- Plant Pathology Lab, ICAR-Central Citrus Research Institute, Amravati Road, Nagpur, 440033, India
| | - Salvinder Singh
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, 785013, India
| | - Virendra K Baranwal
- Advanced Centre for Plant Virology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Ashok Kumar
- Plant Pathology Lab, ICAR-Central Citrus Research Institute, Amravati Road, Nagpur, 440033, India
| | - Sagar Nerkar
- Plant Pathology Lab, ICAR-Central Citrus Research Institute, Amravati Road, Nagpur, 440033, India
| |
Collapse
|
24
|
Thapa N, Danyluk MD, Gerberich KM, Johnson EG, Dewdney MM. Assessment of the Effect of Thermotherapy on ' Candidatus Liberibacter asiaticus' Viability in Woody Tissue of Citrus via Graft-Based Assays and RNA Assays. PHYTOPATHOLOGY 2021; 111:808-818. [PMID: 32976056 DOI: 10.1094/phyto-04-20-0152-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In 2019, citrus production in Florida declined by more than 70%, mostly because of Huanglongbing (HLB), which is caused by the bacterium 'Candidatus Liberibacter asiaticus' (CLas). Thermotherapy for HLB-affected trees was proposed as a short-term management solution to maintain field productivity. It was hypothesized that thermotherapy could eliminate HLB from affected branches; therefore, the study objectives were to show which time-temperature combinations eliminated CLas from woody tissues. Hardening, rounded Valencia twigs collected from HLB-affected field trees were treated in a steam chamber at different time-temperature combinations (50°C for 60 s; 55°C for 0, 30, 60, 90, and 120 s; 60°C for 30 s; and an untreated control). Three independent repetitions of 13 branches per treatment were grafted onto healthy rootstocks and tested to detect CLas after 6, 9, and 12 months. For the RNA-based CLas viability assay, three branches per treatment were treated and bark samples were peeled for RNA extraction and subsequent gene expression analyses. During the grafting study, at 12 months after grafting, a very low frequency of trees grafted with twigs treated at 55°C for 90 s and 55°C for 120 s had detectable CLas DNA. In the few individuals with CLas, titers were significantly lower (P ≤ 0.0001) and could have been remnants of degrading DNA. Additionally, there was a significant decrease (P ≤ 0.0001) in CLas 16S rRNA expression at 55°C for 90 s, 55°C for 120 s, and 60°C for 30 s (3.4-fold change, 3.4-fold change, and 2.3-fold change, respectively) in samples 5 days after treatment. Heat injury, not total CLas kill, could explain the limited changes in transcriptional activity; however, failed recovery and eventual death of CLas resulted in no CLas detection in most of the grafted trees treated with the highest temperatures or longest durations.
Collapse
Affiliation(s)
- Naweena Thapa
- Plant Pathology Department, Citrus Research and Education Center, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850
| | - Michelle D Danyluk
- Food Science and Human Nutrition, Citrus Research and Education Center, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850
| | - Kayla M Gerberich
- Plant Pathology Department, Citrus Research and Education Center, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850
| | - Evan G Johnson
- Plant Pathology Department, Citrus Research and Education Center, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850
| | - Megan M Dewdney
- Plant Pathology Department, Citrus Research and Education Center, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850
| |
Collapse
|
25
|
Cui X, Liu K, Atta S, Zeng C, Zhou C, Wang X. Two Unique Prophages of ' Candidatus Liberibacter asiaticus' Strains from Pakistan. PHYTOPATHOLOGY 2021; 111:784-788. [PMID: 33356428 DOI: 10.1094/phyto-10-20-0454-sc] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
'Candidatus Liberibacter asiaticus' (CLas) is a pathogen causing Huanglongbing (HLB, yellow shoot disease), which is highly destructive to citrus production. The CLas strains harbor prophages. We identified two unique prophages, designated as P-PA19-1 and P-PA19-2, in CLas strain PA19 from Pakistan using next-generation sequencing analysis. P-PA19-1 prophage has high sequence similarity (identity: 78.23%) at the early-gene region of prophage SC1 (Type 1), but it is significantly divergent in the late-gene region (identity: 62.03%). P-PA19-2 was highly similar to SC2 (Type 2) in the late gene region (identity: 97.96%), and also in the early gene region except for a deletion of a 7,179-bp nucleotide sequence that contains a CRISPR/cas system in SC2. Both P-PA19-1 and P-PA19-2 had circular plasmid forms, and only P-PA19-2 was found integrated in the PA19 chromosome. The two new prophages were only found in Pakistani samples. Identification of prophages enhances our understanding of CLas genomic diversity and also the biology and evolution of CLas prophages.
Collapse
Affiliation(s)
- Xuejin Cui
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Chongqing 400712, China
| | - Kehong Liu
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Chongqing 400712, China
| | - Sagheer Atta
- Department of Plant Protection, Faculty of Agricultural Sciences, Ghazi University, Dera Ghazi Khan 32200, Pakistan
| | - Chunhua Zeng
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Chongqing 400712, China
| | - Changyong Zhou
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Chongqing 400712, China
| | - Xuefeng Wang
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Chongqing 400712, China
| |
Collapse
|
26
|
Li T, Zhang L, Deng Y, Deng X, Zheng Z. Establishment of a Cuscuta campestris-mediated enrichment system for genomic and transcriptomic analyses of 'Candidatus Liberibacter asiaticus'. Microb Biotechnol 2021; 14:737-751. [PMID: 33655703 PMCID: PMC7936317 DOI: 10.1111/1751-7915.13773] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 01/30/2021] [Accepted: 02/01/2021] [Indexed: 01/16/2023] Open
Abstract
‘Candidatus Liberibacter asiaticus’ (CLas) is a phloem‐limited non‐culturable α‐proteobacterium associated with citrus Huanglongbing, a highly destructive disease threatening global citrus industry. Research on CLas is challenging due to the current inability to culture CLas in vitro and the low CLas titre in citrus plant. Here, we develop a CLas enrichment system using the holoparasitic dodder plant (Cuscuta campestris) as an amenable host to acquire and enrich CLas from CLas‐infected citrus shoots maintained hydroponically. Forty‐eight out of fifty‐five (87%) dodder plants successfully parasitized CLas‐infected citrus shoots with detectable CLas by PCR. Among 48 dodders cultures, 30 showed two‐ to 419‐fold CLas titre increase as compared to the corresponding citrus hosts. The CLas population rapidly increased and reached the highest level in dodder tendrils at 15 days after parasitizing citrus shoot. Genome sequencing and assembly derived from CLas‐enriched dodder DNA samples generated a higher resolution than those obtained for CLas from citrus hosts. No genomic variation was detected in CLas after transmission from citrus to dodder during short‐term parasitism. Dual RNA‐Seq experiments showed similar CLas gene expression profiles in dodder and citrus samples, yet dodder samples generated a higher resolution of CLas transcriptome data. The ability of dodder to support CLas multiplication to high levels, as well as its advantage in CLas genomic and transcriptomic analyses, make it an optimal model for further studies on CLas–host interaction.
Collapse
Affiliation(s)
- Tao Li
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, 510642, China.,Citrus Huanglongbing Research Laboratory, South China Agricultural University, Guangzhou, Guangdong, 510642, China
| | - Ling Zhang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, 510642, China.,Citrus Huanglongbing Research Laboratory, South China Agricultural University, Guangzhou, Guangdong, 510642, China
| | - Yunshuang Deng
- Citrus Huanglongbing Research Laboratory, South China Agricultural University, Guangzhou, Guangdong, 510642, China
| | - Xiaoling Deng
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, 510642, China.,Citrus Huanglongbing Research Laboratory, South China Agricultural University, Guangzhou, Guangdong, 510642, China
| | - Zheng Zheng
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, Guangdong, 510642, China.,Citrus Huanglongbing Research Laboratory, South China Agricultural University, Guangzhou, Guangdong, 510642, China
| |
Collapse
|
27
|
Silva PA, Huang J, Wulff NA, Zheng Z, Krugner R, Chen J. Genome Sequence Resource of ' Candidatus Liberibacter asiaticus' strain 9PA From Brazil. PLANT DISEASE 2021; 105:199-201. [PMID: 32697180 DOI: 10.1094/pdis-05-20-1018-a] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
'Candidatus Liberibacter asiaticus', an unculturable α-proteobacterium, is associated with citrus huanglongbing (HLB), a devastating disease threatening citrus production in Brazil and worldwide. In this study, a draft whole-genome sequence of 'Ca. L. asiaticus' strain 9PA from a sweet orange (cultivar Pera) tree collected in São Paulo State, Brazil, is reported. The 9PA genome is 1,231,881 bp, including two prophages, with G+C content of 36.7%. This is the first report of a whole-genome sequence of 'Ca. L. asiaticus' from Brazil or South America. The 9PA genome sequence will enrich 'Ca. L. asiaticus' genome resources and facilitate HLB research and control in Brazil and the world.
Collapse
Affiliation(s)
- P A Silva
- Fundo de Defesa da Citricultura-Fundecitrus, Araraquara, SP, Brazil
| | - J Huang
- South China Agricultural University, Guangzhou, Guangdong, China
| | - N A Wulff
- Fundo de Defesa da Citricultura-Fundecitrus, Araraquara, SP, Brazil
| | - Z Zheng
- South China Agricultural University, Guangzhou, Guangdong, China
| | - R Krugner
- United States Department of Agriculture-Agricultural Research Service, San Joaquín Valley Agricultural Sciences Center, Parlier, CA 93648, U.S.A
| | - J Chen
- United States Department of Agriculture-Agricultural Research Service, San Joaquín Valley Agricultural Sciences Center, Parlier, CA 93648, U.S.A
| |
Collapse
|
28
|
Thapa SP, De Francesco A, Trinh J, Gurung FB, Pang Z, Vidalakis G, Wang N, Ancona V, Ma W, Coaker G. Genome-wide analyses of Liberibacter species provides insights into evolution, phylogenetic relationships, and virulence factors. MOLECULAR PLANT PATHOLOGY 2020; 21:716-731. [PMID: 32108417 PMCID: PMC7170780 DOI: 10.1111/mpp.12925] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 01/27/2020] [Accepted: 01/28/2020] [Indexed: 05/04/2023]
Abstract
'Candidatus Liberibacter' species are insect-transmitted, phloem-limited α-Proteobacteria in the order of Rhizobiales. The citrus industry is facing significant challenges due to huanglongbing, associated with infection from 'Candidatus Liberibacter asiaticus' (Las). In order to gain greater insight into 'Ca. Liberibacter' biology and genetic diversity, we have performed genome sequencing and comparative analyses of diverse 'Ca. Liberibacter' species, including those that can infect citrus. Our phylogenetic analysis differentiates 'Ca. Liberibacter' species and Rhizobiales in separate clades and suggests stepwise evolution from a common ancestor splitting first into nonpathogenic Liberibacter crescens followed by diversification of pathogenic 'Ca. Liberibacter' species. Further analysis of Las genomes from different geographical locations revealed diversity among isolates from the United States. Our phylogenetic study also indicates multiple Las introduction events in California and spread of the pathogen from Florida to Texas. Texan Las isolates were closely related, while Florida and Asian isolates exhibited the most genetic variation. We have identified conserved Sec translocon (SEC)-dependent effectors likely involved in bacterial survival and virulence of Las and analysed their expression in their plant host (citrus) and insect vector (Diaphorina citri). Individual SEC-dependent effectors exhibited differential expression patterns between host and vector, indicating that Las uses its effector repertoire to differentially modulate diverse organisms. Collectively, this work provides insights into the evolution of 'Ca. Liberibacter' species, the introduction of Las in the United States and identifies promising Las targets for disease management.
Collapse
Affiliation(s)
- Shree P. Thapa
- Department of Plant PathologyUniversity of CaliforniaDavisCAUSA
| | - Agustina De Francesco
- Department of Microbiology and Plant PathologyUniversity of CaliforniaRiversideCAUSA
| | - Jessica Trinh
- Department of Microbiology and Plant PathologyUniversity of CaliforniaRiversideCAUSA
| | - Fatta B. Gurung
- Citrus CenterDepartment of Agriculture, Agribusiness and Environmental SciencesTexas A&M University‐KingsvilleWeslacoTXUSA
| | - Zhiqian Pang
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceUniversity of FloridaLake AlfredFLUSA
| | - Georgios Vidalakis
- Department of Microbiology and Plant PathologyUniversity of CaliforniaRiversideCAUSA
| | - Nian Wang
- Citrus Research and Education CenterDepartment of Microbiology and Cell ScienceUniversity of FloridaLake AlfredFLUSA
| | - Veronica Ancona
- Citrus CenterDepartment of Agriculture, Agribusiness and Environmental SciencesTexas A&M University‐KingsvilleWeslacoTXUSA
| | - Wenbo Ma
- Department of Microbiology and Plant PathologyUniversity of CaliforniaRiversideCAUSA
| | - Gitta Coaker
- Department of Plant PathologyUniversity of CaliforniaDavisCAUSA
| |
Collapse
|
29
|
Li T, Thaochan N, Huang J, Chen J, Deng X, Zheng Z. Genome Sequence Resource of ' Candidatus Liberibacter asiaticus' from Thailand. PLANT DISEASE 2020; 104:624-626. [PMID: 31910113 DOI: 10.1094/pdis-07-19-1520-a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
'Candidatus Liberibacter asiaticus' (Las) is an unculturable α-proteobacterium associated with citrus huanglongbing (HLB), a devastating disease currently threatening the citrus industry worldwide. Here, we present the genome sequence of Las strain TaiYZ2 from an HLB-affected pomelo tree in Hat Yai district, Songkhla Province, Thailand. The TaiYZ2 genome is composed of 1,230,623 bp with G+C content of 36.4%. This is the first Las genome sequence from Thailand, which will enrich current Las genome resource and facilitate HLB research and management.
Collapse
Affiliation(s)
- Tao Li
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Narit Thaochan
- Pest Management Biotechnology and Plant Physiology Laboratory, Faculty of Natural Resources, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Jiaquan Huang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
- San Joaquin Valley Agricultural Sciences Center, Agricultural Research Service, United States Department of Agriculture, Parlier, California, U.S.A
| | - Jianchi Chen
- San Joaquin Valley Agricultural Sciences Center, Agricultural Research Service, United States Department of Agriculture, Parlier, California, U.S.A
| | - Xiaoling Deng
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Zheng Zheng
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| |
Collapse
|
30
|
Singh YH, Sharma SK, Sinha B, Baranwal VK, Singh NB, Chanu NT, Roy SS, Ansari MA, Ningombam A, Devi PS, Das AK, Singh S, Singh KM, Prakash N. Genetic Variability Based on Tandem Repeat Numbers in a Genomic Locus of ' Candidatus Liberibacter asiaticus' Prevalent in North East India. THE PLANT PATHOLOGY JOURNAL 2019; 35:644-653. [PMID: 31832044 PMCID: PMC6901247 DOI: 10.5423/ppj.oa.03.2019.0061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 08/23/2019] [Accepted: 09/05/2019] [Indexed: 06/10/2023]
Abstract
The genetic variability of 'Candidatus Liberibacter asiaticus' (CLas) population associated with huanglongbing (HLB) disease of citrus in North Eastern (NE) region of India, a geographically locked region, and home for the diversity of many citrus species was analyzed on the basis of tandem repeat numbers (TRN) in variable CLIBASIA_01645 genomic loci. Fifty-five CLas strains sampled from different groves of NE Hill (NEH) region of India were in single amplicon group, but there was remarkable genetic variability in TRNs. The TRN in HLB-associated CLas strains varied from 0-21 and two novel repeat motifs were also identified. Among the NE population of CLas, TRN5 and TRN9 were most frequent (total frequency of 36.36%) followed by TRN4 (14.55%) and TRN6, TNR7 with a frequency of 12.73% each. Class II type CLas genotypes (5 < TRN ≤ 10) had highest prevalence (frequency of 60.00%) in the samples characterized in present study. Class I (TRN ≤ 5) genotypes were second highest prevalent (29.09%) in the NEH region. Further analysis of genetic diversity parameters using Nei's measure (H value) indicated wide genetic diversity in the CLas strains of NE India (H value of 0.58-0.86). Manipur CLas strains had highest genetic variability (0.86) as compared to Eastern, Southern and Central India. The R10 values (TRN ≤ 10/TRN > 10) of NE CLas population was 10.43 (73/7), higher from other regions of India. Present study conclusively reported the occurrence of high genetic variability in TRN of CLas population in North East Indian citrus groves which have evolved to adapt to the specific ecological niche.
Collapse
Affiliation(s)
- Yanglem Herojit Singh
- Department of Plant Pathology, College of Agriculture, Central Agricultural University, Imphal 795004,
India
| | | | - Bireswar Sinha
- Department of Plant Pathology, College of Agriculture, Central Agricultural University, Imphal 795004,
India
| | - Virendra Kumar Baranwal
- Advanced Centre for Plant Virology, Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi 110012,
India
| | | | - Ngathem Taibangnganbi Chanu
- ICAR Research Complex for NEH Region, Manipur Centre, Imphal 795004,
India
- College of Horticulture and Forestry, Central Agricultural University, Pasighat 791102,
India
| | - Subhra S. Roy
- ICAR Research Complex for NEH Region, Manipur Centre, Imphal 795004,
India
| | - Meraj A. Ansari
- ICAR Research Complex for NEH Region, Manipur Centre, Imphal 795004,
India
| | - Arati Ningombam
- ICAR Research Complex for NEH Region, Manipur Centre, Imphal 795004,
India
| | - Ph. Sobita Devi
- Department of Plant Pathology, College of Agriculture, Central Agricultural University, Imphal 795004,
India
| | - Ashis Kumar Das
- ICAR-Central Citrus Research Institute, Nagpur 440010,
India
| | - Salvinder Singh
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat 785013,
India
| | - K. Mamocha Singh
- Department of Entomology, College of Agriculture, Central Agricultural University, Imphal 795004,
India
| | - Narendra Prakash
- ICAR Research Complex for NEH Region, Manipur Centre, Imphal 795004,
India
| |
Collapse
|
31
|
Functional and Comparative Genomic Analysis of Integrated Prophage-Like Sequences in " Candidatus Liberibacter asiaticus". mSphere 2019; 4:4/6/e00409-19. [PMID: 31722990 PMCID: PMC6854039 DOI: 10.1128/msphere.00409-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Huanglongbing (HLB) disease is threatening citrus production worldwide. The causative agent is “Candidatus Liberibacter asiaticus.” Prior work using mapping-based approaches identified prophage-like sequences in some “Ca. Liberibacter asiaticus” genomes but not all. Here, we utilized a de novo approach that expands the number of prophage-like elements found in “Ca. Liberibacter asiaticus” from 16 to 33 and identified at least one prophage-like sequence in all “Ca. Liberibacter asiaticus” strains. Furthermore, we identified a prophage-like sequence type that is a remnant of an integrated prophage—expanding the number of prophage types in “Ca. Liberibacter asiaticus” from 3 to 4. Overall, the findings will help researchers investigate the role of prophage in the ecology, evolution, and pathogenicity of “Ca. Liberibacter asiaticus.” Huanglongbing disease (HLB; yellow shoot disease) is a severe worldwide infectious disease for citrus family plants. The pathogen “Candidatus Liberibacter asiaticus” is an alphaproteobacterium of the Rhizobiaceae family that has been identified as the causative agent of HLB. The virulence of “Ca. Liberibacter asiaticus” has been attributed, in part, to prophage-carried genes. Prophage and prophage-like elements have been identified in 12 of the 15 available “Ca. Liberibacter asiaticus” genomes and are classified into three prophage types. Here, we reexamined all 15 “Ca. Liberibacter asiaticus” genomes using a de novo prediction approach and expanded the number of prophage-like elements from 16 to 33. Further, we found that all of the “Ca. Liberibacter asiaticus” genomes contained at least one prophage-like sequence. Comparative analysis revealed a prevalent, albeit previously unknown, prophage-like sequence type that is a remnant of an integrated prophage. Notably, this remnant prophage is found in the Ishi-1 “Ca. Liberibacter asiaticus” strain that had previously been reported as lacking prophages. Our findings provide both a resource for data and new insights into the evolutionary relationship between phage and “Ca. Liberibacter asiaticus” pathogenicity. IMPORTANCE Huanglongbing (HLB) disease is threatening citrus production worldwide. The causative agent is “Candidatus Liberibacter asiaticus.” Prior work using mapping-based approaches identified prophage-like sequences in some “Ca. Liberibacter asiaticus” genomes but not all. Here, we utilized a de novo approach that expands the number of prophage-like elements found in “Ca. Liberibacter asiaticus” from 16 to 33 and identified at least one prophage-like sequence in all “Ca. Liberibacter asiaticus” strains. Furthermore, we identified a prophage-like sequence type that is a remnant of an integrated prophage—expanding the number of prophage types in “Ca. Liberibacter asiaticus” from 3 to 4. Overall, the findings will help researchers investigate the role of prophage in the ecology, evolution, and pathogenicity of “Ca. Liberibacter asiaticus.”
Collapse
|
32
|
Dominguez-Mirazo M, Jin R, Weitz JS. Functional and Comparative Genomic Analysis of Integrated Prophage-Like Sequences in " Candidatus Liberibacter asiaticus". mSphere 2019; 4. [PMID: 31722990 DOI: 10.1101/661967] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023] Open
Abstract
Huanglongbing disease (HLB; yellow shoot disease) is a severe worldwide infectious disease for citrus family plants. The pathogen "Candidatus Liberibacter asiaticus" is an alphaproteobacterium of the Rhizobiaceae family that has been identified as the causative agent of HLB. The virulence of "Ca. Liberibacter asiaticus" has been attributed, in part, to prophage-carried genes. Prophage and prophage-like elements have been identified in 12 of the 15 available "Ca. Liberibacter asiaticus" genomes and are classified into three prophage types. Here, we reexamined all 15 "Ca. Liberibacter asiaticus" genomes using a de novo prediction approach and expanded the number of prophage-like elements from 16 to 33. Further, we found that all of the "Ca. Liberibacter asiaticus" genomes contained at least one prophage-like sequence. Comparative analysis revealed a prevalent, albeit previously unknown, prophage-like sequence type that is a remnant of an integrated prophage. Notably, this remnant prophage is found in the Ishi-1 "Ca. Liberibacter asiaticus" strain that had previously been reported as lacking prophages. Our findings provide both a resource for data and new insights into the evolutionary relationship between phage and "Ca. Liberibacter asiaticus" pathogenicity.IMPORTANCE Huanglongbing (HLB) disease is threatening citrus production worldwide. The causative agent is "Candidatus Liberibacter asiaticus." Prior work using mapping-based approaches identified prophage-like sequences in some "Ca. Liberibacter asiaticus" genomes but not all. Here, we utilized a de novo approach that expands the number of prophage-like elements found in "Ca. Liberibacter asiaticus" from 16 to 33 and identified at least one prophage-like sequence in all "Ca. Liberibacter asiaticus" strains. Furthermore, we identified a prophage-like sequence type that is a remnant of an integrated prophage-expanding the number of prophage types in "Ca. Liberibacter asiaticus" from 3 to 4. Overall, the findings will help researchers investigate the role of prophage in the ecology, evolution, and pathogenicity of "Ca. Liberibacter asiaticus."
Collapse
Affiliation(s)
- Marian Dominguez-Mirazo
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- Interdisciplinary Graduate Program in Quantitative Biosciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Rong Jin
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Joshua S Weitz
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia, USA
| |
Collapse
|
33
|
Lessons from One Fastidious Bacterium to Another: What Can We Learn about Liberibacter Species from Xylella fastidiosa. INSECTS 2019; 10:insects10090300. [PMID: 31527458 PMCID: PMC6780969 DOI: 10.3390/insects10090300] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 09/11/2019] [Accepted: 09/12/2019] [Indexed: 02/06/2023]
Abstract
Huanglongbing is causing economic devastation to the citrus industry in Florida, and threatens the industry everywhere the bacterial pathogens in the Candidatus Liberibacter genus and their insect vectors are found. Bacteria in the genus cannot be cultured and no durable strategy is available for growers to control plant infection or pathogen transmission. However, scientists and grape growers were once in a comparable situation after the emergence of Pierce’s disease, which is caused by Xylella fastidiosa and spread by its hemipteran insect vector. Proactive quarantine and vector control measures coupled with interdisciplinary data-driven science established control of this devastating disease and pushed the frontiers of knowledge in the plant pathology and vector biology fields. Our review highlights the successful strategies used to understand and control X. fastidiosa and their potential applicability to the liberibacters associated with citrus greening, with a focus on the interactions between bacterial pathogen and insect vector. By placing the study of Candidatus Liberibacter spp. within the current and historical context of another fastidious emergent plant pathogen, future basic and applied research to develop control strategies can be prioritized.
Collapse
|
34
|
Merfa MV, Pérez-López E, Naranjo E, Jain M, Gabriel DW, De La Fuente L. Progress and Obstacles in Culturing ' Candidatus Liberibacter asiaticus', the Bacterium Associated with Huanglongbing. PHYTOPATHOLOGY 2019; 109:1092-1101. [PMID: 30998129 DOI: 10.1094/phyto-02-19-0051-rvw] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In recent decades, 'Candidatus Liberibacter spp.' have emerged as a versatile group of psyllid-vectored plant pathogens and endophytes capable of infecting a wide range of economically important plant hosts. The most notable example is 'Candidatus Liberibacter asiaticus' (CLas) associated with Huanglongbing (HLB) in several major citrus-producing areas of the world. CLas is a phloem-limited α-proteobacterium that is primarily vectored and transmitted among citrus species by the Asian citrus psyllid (ACP) Diaphorina citri. HLB was first detected in North America in Florida (USA) in 2005, following introduction of the ACP to the State in 1998. HLB rapidly spread to all citrus growing regions of Florida within three years, with severe economic consequences to growers and considerable expense to taxpayers of the state and nation. Inability to establish CLas in culture (except transiently) remains a significant scientific challenge toward effective HLB management. Lack of axenic cultures has restricted functional genomic analyses, transfer of CLas to either insect or plant hosts for fulfillment of Koch's postulates, characterization of host-pathogen interactions and effective screening of antibacterial compounds. In the last decade, substantial progress has been made toward CLas culturing: (i) three reports of transient CLas cultures were published, (ii) a new species of Liberibacter was identified and axenically cultured from diseased mountain papaya (Liberibacter crescens strain BT-1), (iii) psyllid hemolymph and citrus phloem sap were biochemically characterized, (iv) CLas phages were identified and lytic genes possibly affecting CLas growth were described, and (v) genomic sequences of 15 CLas strains were made available. In addition, development of L. crescens as a surrogate host for functional analyses of CLas genes, has provided valuable insights into CLas pathogenesis and its physiological dependence on the host cell. In this review we summarize the conclusions from these important studies.
Collapse
Affiliation(s)
- Marcus V Merfa
- 1 Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, U.S.A
| | - Edel Pérez-López
- 1 Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, U.S.A
| | - Eber Naranjo
- 1 Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, U.S.A
| | - Mukesh Jain
- 2 Department of Plant Pathology, University of Florida, Gainesville, FL 32611, U.S.A
| | - Dean W Gabriel
- 2 Department of Plant Pathology, University of Florida, Gainesville, FL 32611, U.S.A
| | - Leonardo De La Fuente
- 1 Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, U.S.A
| |
Collapse
|
35
|
da Silva PA, Fassini CG, Sampaio LS, Dequigiovanni G, Zucchi MI, Wulff NA. Genetic Diversity of ' Candidatus Liberibacter asiaticus' Revealed by Short Tandem Repeats and Prophage Typing Indicates Population Homogeneity in Brazil. PHYTOPATHOLOGY 2019; 109:960-971. [PMID: 30694114 DOI: 10.1094/phyto-08-18-0295-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
'Candidatus Liberibacter asiaticus' is the most common huanglongbing-associated bacteria, being present in Asia, South, Central, and North America. Genomic approaches enabled sequencing of 'Ca. L. asiaticus' genomes, allowing for a broader assessment of its genetic variability with the application of polymerase chain reaction (PCR)-based tools such as microsatellite or short tandem repeat (STR) analysis. Although these tools contributed to a detailed analysis of strains from Japan, China, and the United States, Brazilian strains were analyzed in either too few samples with several STRs or in several strains with only a single microsatellite and a single PCR marker. We used 573 'Ca. L. asiaticus' strains, mainly collected from São Paulo State (SPS), in our genetic analyses, employing three STRs and several prophage PCR markers. STR revealed a homogeneous population regardless of sampling year or geographic regions of SPS. Thirty-eight haplotypes were recognized with a predominance of VNTR_005 higher than 10 repeats, with VNTR_002 and VNTR_077 containing 11 and 8 repeats, respectively. This haplotype is indicated as class HE, which comprised 80.28% of strains. Classes HA and HB, predominant in Florida, were not found. A new genomic organization in the junction of prophages SC2 and SC1 is prevalent in Brazilian strains, indicating gene rearrangement and a widespread occurrence of a type 1 prophage as well as the presence of a type 2-like prophage. Our results indicate that 'Ca. L. asiaticus' populations are homogeneous and harbor a new genomic organization in prophages type 1 and 2.
Collapse
Affiliation(s)
| | - Camila Giacomo Fassini
- 1 Departamento de Pesquisa & Desenvolvimento-Fundecitrus, Araraquara, SP, 14807-040, Brazil
| | - Laís Simões Sampaio
- 1 Departamento de Pesquisa & Desenvolvimento-Fundecitrus, Araraquara, SP, 14807-040, Brazil
| | - Gabriel Dequigiovanni
- 2 Agência Paulista de Tecnologia dos Agronegócios, Polo Regional Centro-Sul, Rodovia SP 127, km 30, Piracicaba, SP, 13400-970 Brazil; and
| | - Maria Imaculada Zucchi
- 2 Agência Paulista de Tecnologia dos Agronegócios, Polo Regional Centro-Sul, Rodovia SP 127, km 30, Piracicaba, SP, 13400-970 Brazil; and
| | - Nelson Arno Wulff
- 1 Departamento de Pesquisa & Desenvolvimento-Fundecitrus, Araraquara, SP, 14807-040, Brazil
- 3 PPG Biotecnologia, IQ/UNESP Araraquara, SP, 14800-060, Brazil
| |
Collapse
|
36
|
Hao G, Ammar D, Duan Y, Stover E. Transgenic citrus plants expressing a ‘Candidatus Liberibacter asiaticus’ prophage protein LasP235 display Huanglongbing-like symptoms. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.aggene.2019.100085] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
37
|
Dai Z, Wu F, Zheng Z, Yokomi R, Kumagai L, Cai W, Rascoe J, Polek M, Chen J, Deng X. Prophage Diversity of 'Candidatus Liberibacter asiaticus' Strains in California. PHYTOPATHOLOGY 2019; 109:551-559. [PMID: 30303769 DOI: 10.1094/phyto-06-18-0185-r] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Huanglongbing (HLB) is a highly destructive citrus disease and is associated with a nonculturable bacterium, 'Candidatus Liberibacter asiaticus'. 'Ca. L. asiaticus' in the United States was first found in Florida in 2005 and is now endemic there. In California, 'Ca. L. asiaticus' was first detected in Hacienda Heights in Los Angeles County in 2012 and has now been detected in multiple urban locations in southern California. Knowledge of 'Ca. L. asiaticus' strain diversity in California is important for HLB management. In this study, genomic diversity among 10 'Ca. L. asiaticus' strains from six California locations were analyzed using a next-generation sequencing (NGS) (Illumina MiSeq and HiSeq) approach. Draft genome sequences of 'Ca. L. asiaticus' strains were assembled. Sequences of the 16S ribosomal RNA gene and nrdB confirmed 'Ca. L. asiaticus' identity. Prophages were detected in all 'Ca. L. asiaticus' strains. The California 'Ca. L. asiaticus' strains formed four prophage typing groups (PTGs): PTG1, with type 1 prophage only (strains from Anaheim, San Gabriel, and Riverside); PTG2, with type 2 prophage only (strains from Hacienda Heights); PTG1-3, with both type 1 and 3 prophages (a strain from Cerritos); and PTG1-2, with both type 1 and type 2 prophages (a strain from La Habra). Analyses of the terL sequence showed that all California 'Ca. L. asiaticus' strains were not introduced from Florida but likely from locations in Asia. Miniature inverted-repeat transposable elements were found in all 'Ca. L. asiaticus' strains, yet, a jumping-out event was detected in the 'Ca. L. asiaticus' strain from Cerritos. Altogether, this study demonstrated that the NGS approach focusing on prophage variation was sensitive and effective in revealing diversity of 'Ca. L. asiaticus' strains in California.
Collapse
Affiliation(s)
- Z Dai
- 1 Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China
| | - F Wu
- 1 Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China
| | - Z Zheng
- 1 Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China
| | - R Yokomi
- 2 United States Department of Agriculture (USDA)-Agricultural Research Service, San Joaquín Valley Agricultural Sciences Center, Parlier, CA, U.S.A
| | - L Kumagai
- 3 Plant Pest Diagnostic Center, California Department of Food and Agriculture, Sacramento, U.S.A
| | - W Cai
- 4 USDA Animal and Plant Health Inspection Service-Plant Protection and Quarantine, Beltsville, MD, U.S.A.; and
| | - J Rascoe
- 3 Plant Pest Diagnostic Center, California Department of Food and Agriculture, Sacramento, U.S.A
| | - M Polek
- 5 National Clonal Germplasm Repository for Citrus and Dates, Riverside, CA, U.S.A
| | - J Chen
- 2 United States Department of Agriculture (USDA)-Agricultural Research Service, San Joaquín Valley Agricultural Sciences Center, Parlier, CA, U.S.A
| | - X Deng
- 1 Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China
| |
Collapse
|
38
|
Chen Y, Li T, Zheng Z, Xu M, Deng X. Draft Whole-Genome Sequence of a " Candidatus Liberibacter asiaticus" Strain from Yunnan, China. Microbiol Resour Announc 2019; 8:e01413-18. [PMID: 30687827 PMCID: PMC6346159 DOI: 10.1128/mra.01413-18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 12/11/2018] [Indexed: 11/22/2022] Open
Abstract
The draft genome sequence of "Candidatus Liberibacter asiaticus" strain YNJS7C, isolated from a navel orange tree in Yunnan Province, China, is presented here. The YNJS7C strain has a genome size of 1,258,986 bp, with a G+C content of 36.6%, 1,174 predicted open reading frames, and 53 RNA genes.
Collapse
Affiliation(s)
- Yanling Chen
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China
| | - Tao Li
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China
| | - Zheng Zheng
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China
| | - Meirong Xu
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China
| | - Xiaoling Deng
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China
| |
Collapse
|
39
|
Fujiwara K, Iwanami T, Fujikawa T. Alterations of Candidatus Liberibacter asiaticus-Associated Microbiota Decrease Survival of Ca. L. asiaticus in in vitro Assays. Front Microbiol 2018; 9:3089. [PMID: 30622518 PMCID: PMC6308922 DOI: 10.3389/fmicb.2018.03089] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 11/29/2018] [Indexed: 11/28/2022] Open
Abstract
Phloem-inhabiting bacterial phytopathogens often have smaller genomes than other bacterial phytopathogens. It is thought that they depend on both other phloem microbiota and phloem nutrients for colonization of the host. However, the mechanism underlying associations between phloem-inhabiting phytopathogens and other phloem microbiota are poorly understood. Here, we demonstrate that the survival of Candidatus Liberibacter asiaticus (CLas), a cause of huanglongbing (citrus greening disease), depends on interplay with a specific subset of CLas-associated microbiota. CLas was not susceptible to oxytetracycline in vitro. However, oxytetracycline treatment eliminated a particular sub-community dominated by the Comamonadaceae, Flavobacteriaceae, Microbacteriaceae, and Pseudomonadaceae, decreasing CLas survival. We speculate that CLas uses ecological services derived from CLas-associated microbiota to colonize the host and to construct a pathogen-associated community that stimulates disease development.
Collapse
Affiliation(s)
- Kazuki Fujiwara
- Kyushu Okinawa Agricultural Research Center, National Agriculture and Food Research Organization, Koshi, Japan
| | - Toru Iwanami
- Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Takashi Fujikawa
- Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization, Tsukuba, Japan
| |
Collapse
|
40
|
Jain M, Munoz-Bodnar A, Zhang S, Gabriel DW. A Secreted 'Candidatus Liberibacter asiaticus' Peroxiredoxin Simultaneously Suppresses Both Localized and Systemic Innate Immune Responses In Planta. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:1312-1322. [PMID: 29953333 DOI: 10.1094/mpmi-03-18-0068-r] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The oxidative (H2O2) burst is a seminal feature of the basal plant defense response to attempted pathogen invasions. In 'Candidatus Liberibacter asiaticus' UF506, expression of the SC2 prophage-encoded secreted peroxidase (F489_gp15) increases bacterial fitness and delays symptom progression in citrus. Two chromosomal 1-Cys peroxiredoxin genes, CLIBASIA_RS00940 (Lasprx5) and CLIBASIA_RS00445 (Lasbcp), are conserved among all sequenced 'Ca. L. asiaticus' strains, including those lacking prophages. Both LasBCP and LasdPrx5 have only a single conserved peroxidatic Cys (CP/SH) and lack the resolving Cys (CR/SH). Lasprx5 appeared to be a housekeeping gene with similar moderate transcript abundance in both 'Ca. L. asiaticus'-infected psyllids and citrus. By contrast, Lasbcp was expressed only in planta, similar to the expression of the SC2 peroxidase. Since 'Ca. L. asiaticus' is uncultured, Lasbcp and Lasprx5 were functionally validated in a cultured surrogate species, Liberibacter crescens, and both genes significantly increased oxidative stress tolerance and cell viability in culture. LasBCP was nonclassically secreted and, in L. crescens, conferred 214-fold more resistance to tert-butyl hydroperoxide (tBOOH) than wild type. Transient overexpression of Lasbcp in tobacco suppressed H2O2-mediated transcriptional activation of RbohB, the key gatekeeper of the systemic plant defense signaling cascade. Lasbcp expression did not interfere with the perception of 'Ca. L. asiaticus' flagellin (flg22Las) but interrupted the downstream activation of RbohB and stereotypical deposition of callose in tobacco. Critically, LasBCP also protected against tBOOH-induced peroxidative degradation of lipid membranes in planta, preventing subsequent accumulation of antimicrobial oxylipins that can also trigger the localized hypersensitive cell death response.
Collapse
Affiliation(s)
- Mukesh Jain
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, U.S.A
| | | | - Shujian Zhang
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, U.S.A
| | - Dean W Gabriel
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, U.S.A
| |
Collapse
|
41
|
Sudhan D, Puttamuk T, Vuttipongchaikij S, Chuawong P. Cloning, overexpression, and purification of a gene of unknown function of prophage loci from ‘ Candidatus Liberibacter asiaticus,’ the destructive bacterial pathogen of huanglongbing disease in citrus plants. Protein Expr Purif 2018; 150:72-80. [DOI: 10.1016/j.pep.2018.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 05/19/2018] [Accepted: 05/19/2018] [Indexed: 10/16/2022]
|
42
|
Ding F, Allen V, Luo W, Zhang S, Duan Y. Molecular mechanisms underlying heat or tetracycline treatments for citrus HLB control. HORTICULTURE RESEARCH 2018; 5:30. [PMID: 29872535 PMCID: PMC5981314 DOI: 10.1038/s41438-018-0038-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 03/06/2018] [Accepted: 03/27/2018] [Indexed: 05/05/2023]
Abstract
Huanglongbing (HLB), a destructive plant bacterial disease, severely impedes worldwide citrus production. In our previous reports, we revealed the molecular mechanisms of host plant responses that underlie thermotherapy against HLB. In this study, we investigated the molecular mechanism underlying heat or tetracycline treatments on the HLB bacterium, 'Candidatus Liberibacter asiaticus' (Las) by focusing on Las prophage/phage conversion under stress conditions. By comparing the prophage FP1 and FP2 copy number to the copy number of 16S rDNA in HLB-affected plants, we found that the relative copy number of both FP1 and FP2 increased significantly, ranging from 3.4- to 6.7-fold change when Las-infected samples underwent a temperature shift from 23 to 37, 42 or 45 °C. When treated with tetracycline at 50-150 and 200-250 µg/ml, respectively, the relative copy number of both FP1 and FP2 increased by 3.4- to 6.0-fold. In addition, analyses of Las prophage structural gene and antirepressor gene copy numbers showed similar trends for all treatments. Furthermore, transmission electron microscopy provided direct evidence of lysogenic to lytic conversion upon temperature increase. These results not only provide new insight into the molecular mechanisms underlying heat or tetracycline treatment but also suggest a novel HLB control strategy by enhancing the endogenous conversion from Las prophages to phages.
Collapse
Affiliation(s)
- Fang Ding
- Hubei Key Laboratory of PLant Pathology, Huazhong Agricultural University, 430070 Wuhan, Hubei P.R. China
- USDA-ARS-USHRL, Fort Pierce, FL 34945 USA
| | | | - Weiqi Luo
- USDA-ARS-USHRL, Fort Pierce, FL 34945 USA
- Center for Integrated Pest Management, North Carolina State University, Raleigh, NC 27606 USA
| | - Shouan Zhang
- IFAS-TREC, University of Florida, Homestead, FL 33031 USA
| | | |
Collapse
|
43
|
Zheng Z, Bao M, Wu F, Van Horn C, Chen J, Deng X. A Type 3 Prophage of 'Candidatus Liberibacter asiaticus' Carrying a Restriction-Modification System. PHYTOPATHOLOGY 2018; 108:454-461. [PMID: 29192841 DOI: 10.1094/phyto-08-17-0282-r] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Prophages, the lysogenic form of bacterial phages, are important genetic entities of 'Candidatus Liberibacter asiaticus' (CLas), a nonculturable α-proteobacterium associated with citrus Huanglongbing. Two CLas prophages have been described, SC1 (NC_019549.1, Type 1) and SC2 (NC_019550.1, Type 2), which involve the lytic cycle and the lysogenic cycle, respectively. To explore the prophage repertoire, 523 CLas DNA samples extracted from leaf petioles of CLas-infected citrus were collected from southern China and surveyed for Type 1 and Type 2 prophages by specific PCR. Eighteen samples were found lacking both prophages. One sample, JXGC, sequenced using Illumina HiSeq, generated >100 million short sequence reads (150 bp per read). Read mapping to known prophage sequences showed a sequence coverage of 46% to SC1 and 50% to SC2. BLAST search using SC1 and SC2 as queries identified three contigs from the JXGC de novo assembly that form a circular P-JXGC-3 (31,449 bp), designated as a new Type 3 prophage. Chromosomal integration of P-JXGC-3 was detected to occur within a helicase gene, resulting in a duplication of this gene. P-JXGC-3 had 36 open reading frames (ORFs), 10 of which were not found in Type 1 or Type 2 prophages, including four genes that encoded a restriction-modification (R-M) system (hsdR, hsdS, hsdM1, and hsdM2). Typed by prophage-specific PCR, the CLas strains in southern China contained all combinations of the three prophage types with the exception of a Type 2-Type 3 combination, suggesting active ongoing prophage-phage interactions. Based on gene annotation, P-JXGC-3 is not capable of reproduction via the lytic cycle. The R-M system was speculated to play a role against Type 1 prophage-phage invasion.
Collapse
Affiliation(s)
- Zheng Zheng
- First, second, third, and sixth author: Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China; and first, fourth, and fifth authors: San Joaquín Valley Agricultural Sciences Center, Parlier, CA
| | - Minli Bao
- First, second, third, and sixth author: Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China; and first, fourth, and fifth authors: San Joaquín Valley Agricultural Sciences Center, Parlier, CA
| | - Fengnian Wu
- First, second, third, and sixth author: Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China; and first, fourth, and fifth authors: San Joaquín Valley Agricultural Sciences Center, Parlier, CA
| | - Christopher Van Horn
- First, second, third, and sixth author: Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China; and first, fourth, and fifth authors: San Joaquín Valley Agricultural Sciences Center, Parlier, CA
| | - Jianchi Chen
- First, second, third, and sixth author: Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China; and first, fourth, and fifth authors: San Joaquín Valley Agricultural Sciences Center, Parlier, CA
| | - Xiaoling Deng
- First, second, third, and sixth author: Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China; and first, fourth, and fifth authors: San Joaquín Valley Agricultural Sciences Center, Parlier, CA
| |
Collapse
|
44
|
Lou B, Song Y, RoyChowdhury M, Deng C, Niu Y, Fan Q, Tang Y, Zhou C. Development of a Tandem Repeat-Based Polymerase Chain Displacement Reaction Method for Highly Sensitive Detection of 'Candidatus Liberibacter asiaticus'. PHYTOPATHOLOGY 2018; 108:292-298. [PMID: 29019271 DOI: 10.1094/phyto-06-17-0210-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Huanglongbing (HLB) is one of the most destructive diseases in citrus production worldwide. Early detection of HLB pathogens can facilitate timely removal of infected citrus trees in the field. However, low titer and uneven distribution of HLB pathogens in host plants make reliable detection challenging. Therefore, the development of effective detection methods with high sensitivity is imperative. This study reports the development of a novel method, tandem repeat-based polymerase chain displacement reaction (TR-PCDR), for the detection of 'Candidatus Liberibacter asiaticus', a widely distributed HLB-associated bacterium. A uniquely designed primer set (TR2-PCDR-F/TR2-PCDR-1R) and a thermostable Taq DNA polymerase mutant with strand displacement activity were used for TR-PCDR amplification. Performed in a regular thermal cycler, TR-PCDR could produce more than two amplicons after each amplification cycle. Sensitivity of the developed TR-PCDR was 10 copies of target DNA fragment. The sensitive level was proven to be 100× higher than conventional PCR and similar to real-time PCR. Data from the detection of 'Ca. L. asiaticus' with filed samples using the above three methods also showed similar results. No false-positive TR-PCDR amplification was observed from healthy citrus samples and water controls. These results thereby illustrated that the developed TR-PCDR method can be applied to the reliable, highly sensitive, and cost-effective detection of 'Ca. L. asiaticus'.
Collapse
Affiliation(s)
- Binghai Lou
- First author: College of Plant Protection, Southwest University, Chongqing 400715, P.R. China; first, second, fourth, fifth, sixth, and seventh authors: Guangxi Key Laboratory of Citrus Biology, Guangxi Academy of Specialty Crops, Guilin, Guangxi 541004, P.R. China; third author: Department of Biological Sciences, Idaho State University, 650 Memorial Dr., Pocatello 83201; and eighth author: Citrus Research Institute, Southwest University, Chongqing 400715, P.R. China
| | - Yaqin Song
- First author: College of Plant Protection, Southwest University, Chongqing 400715, P.R. China; first, second, fourth, fifth, sixth, and seventh authors: Guangxi Key Laboratory of Citrus Biology, Guangxi Academy of Specialty Crops, Guilin, Guangxi 541004, P.R. China; third author: Department of Biological Sciences, Idaho State University, 650 Memorial Dr., Pocatello 83201; and eighth author: Citrus Research Institute, Southwest University, Chongqing 400715, P.R. China
| | - Moytri RoyChowdhury
- First author: College of Plant Protection, Southwest University, Chongqing 400715, P.R. China; first, second, fourth, fifth, sixth, and seventh authors: Guangxi Key Laboratory of Citrus Biology, Guangxi Academy of Specialty Crops, Guilin, Guangxi 541004, P.R. China; third author: Department of Biological Sciences, Idaho State University, 650 Memorial Dr., Pocatello 83201; and eighth author: Citrus Research Institute, Southwest University, Chongqing 400715, P.R. China
| | - Chongling Deng
- First author: College of Plant Protection, Southwest University, Chongqing 400715, P.R. China; first, second, fourth, fifth, sixth, and seventh authors: Guangxi Key Laboratory of Citrus Biology, Guangxi Academy of Specialty Crops, Guilin, Guangxi 541004, P.R. China; third author: Department of Biological Sciences, Idaho State University, 650 Memorial Dr., Pocatello 83201; and eighth author: Citrus Research Institute, Southwest University, Chongqing 400715, P.R. China
| | - Ying Niu
- First author: College of Plant Protection, Southwest University, Chongqing 400715, P.R. China; first, second, fourth, fifth, sixth, and seventh authors: Guangxi Key Laboratory of Citrus Biology, Guangxi Academy of Specialty Crops, Guilin, Guangxi 541004, P.R. China; third author: Department of Biological Sciences, Idaho State University, 650 Memorial Dr., Pocatello 83201; and eighth author: Citrus Research Institute, Southwest University, Chongqing 400715, P.R. China
| | - Qijun Fan
- First author: College of Plant Protection, Southwest University, Chongqing 400715, P.R. China; first, second, fourth, fifth, sixth, and seventh authors: Guangxi Key Laboratory of Citrus Biology, Guangxi Academy of Specialty Crops, Guilin, Guangxi 541004, P.R. China; third author: Department of Biological Sciences, Idaho State University, 650 Memorial Dr., Pocatello 83201; and eighth author: Citrus Research Institute, Southwest University, Chongqing 400715, P.R. China
| | - Yan Tang
- First author: College of Plant Protection, Southwest University, Chongqing 400715, P.R. China; first, second, fourth, fifth, sixth, and seventh authors: Guangxi Key Laboratory of Citrus Biology, Guangxi Academy of Specialty Crops, Guilin, Guangxi 541004, P.R. China; third author: Department of Biological Sciences, Idaho State University, 650 Memorial Dr., Pocatello 83201; and eighth author: Citrus Research Institute, Southwest University, Chongqing 400715, P.R. China
| | - Changyong Zhou
- First author: College of Plant Protection, Southwest University, Chongqing 400715, P.R. China; first, second, fourth, fifth, sixth, and seventh authors: Guangxi Key Laboratory of Citrus Biology, Guangxi Academy of Specialty Crops, Guilin, Guangxi 541004, P.R. China; third author: Department of Biological Sciences, Idaho State University, 650 Memorial Dr., Pocatello 83201; and eighth author: Citrus Research Institute, Southwest University, Chongqing 400715, P.R. China
| |
Collapse
|
45
|
Bendix C, Lewis JD. The enemy within: phloem-limited pathogens. MOLECULAR PLANT PATHOLOGY 2018; 19:238-254. [PMID: 27997761 PMCID: PMC6638166 DOI: 10.1111/mpp.12526] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/06/2016] [Accepted: 12/08/2016] [Indexed: 05/06/2023]
Abstract
The growing impact of phloem-limited pathogens on high-value crops has led to a renewed interest in understanding how they cause disease. Although these pathogens cause substantial crop losses, many are poorly characterized. In this review, we present examples of phloem-limited pathogens that include intracellular bacteria with and without cell walls, and viruses. Phloem-limited pathogens have small genomes and lack many genes required for core metabolic processes, which is, in part, an adaptation to the unique phloem environment. For each pathogen class, we present multiple case studies to highlight aspects of disease caused by phloem-limited pathogens. The pathogens presented include Candidatus Liberibacter asiaticus (citrus greening), Arsenophonus bacteria, Serratia marcescens (cucurbit yellow vine disease), Candidatus Phytoplasma asteris (Aster Yellows Witches' Broom), Spiroplasma kunkelii, Potato leafroll virus and Citrus tristeza virus. We focus on commonalities in the virulence strategies of these pathogens, and aim to stimulate new discussions in the hope that widely applicable disease management strategies can be found.
Collapse
Affiliation(s)
- Claire Bendix
- United States Department of AgriculturePlant Gene Expression CenterAlbanyCA94710USA
| | - Jennifer D. Lewis
- United States Department of AgriculturePlant Gene Expression CenterAlbanyCA94710USA
- Department of Plant and Microbial BiologyUniversity of California, BerkeleyBerkeleyCA94720USA
| |
Collapse
|
46
|
Johnson MC, Sena-Velez M, Washburn BK, Platt GN, Lu S, Brewer TE, Lynn JS, Stroupe ME, Jones KM. Structure, proteome and genome of Sinorhizobium meliloti phage ΦM5: A virus with LUZ24-like morphology and a highly mosaic genome. J Struct Biol 2017; 200:343-359. [DOI: 10.1016/j.jsb.2017.08.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 07/24/2017] [Accepted: 08/21/2017] [Indexed: 11/26/2022]
|
47
|
Wang N, Pierson EA, Setubal JC, Xu J, Levy JG, Zhang Y, Li J, Rangel LT, Martins J. The Candidatus Liberibacter-Host Interface: Insights into Pathogenesis Mechanisms and Disease Control. ANNUAL REVIEW OF PHYTOPATHOLOGY 2017. [PMID: 28637377 DOI: 10.1146/annurev-phyto-080516-035513] [Citation(s) in RCA: 165] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
"Candidatus Liberibacter" species are associated with economically devastating diseases of citrus, potato, and many other crops. The importance of these diseases as well as the proliferation of new diseases on a wider host range is likely to increase as the insects vectoring the "Ca. Liberibacter" species expand their territories worldwide. Here, we review the progress on understanding pathogenesis mechanisms of "Ca. Liberibacter" species and the control approaches for diseases they cause. We discuss the Liberibacter virulence traits, including secretion systems, putative effectors, and lipopolysaccharides (LPSs), as well as other important traits likely to contribute to disease development, e.g., flagella, prophages, and salicylic acid hydroxylase. The pathogenesis mechanisms of Liberibacters are discussed. Liberibacters secrete Sec-dependent effectors (SDEs) or other virulence factors into the phloem elements or companion cells to interfere with host targets (e.g., proteins or genes), which cause cell death, necrosis, or other phenotypes of phloem elements or companion cells, leading to localized cell responses and systemic malfunction of phloem. Receptors on the remaining organelles in the phloem, such as plastid, vacuole, mitochondrion, or endoplasmic reticulum, interact with secreted SDEs and/or other virulence factors secreted or located on the Liberibacter outer membrane to trigger cell responses. Some of the host genes or proteins targeted by SDEs or other virulence factors of Liberibacters serve as susceptibility genes that facilitate compatibility (e.g., promoting pathogen growth or suppressing immune responses) or disease development. In addition, Liberibacters trigger plant immunity response via pathogen-associated molecular patterns (PAMPs, such as lipopolysaccharides), which leads to premature cell death, callose deposition, or phloem protein accumulation, causing a localized response and/or systemic effect on phloem transportation. Physical presence of Liberibacters and their metabolic activities may disturb the function of phloem, via disrupting osmotic gradients, or the integrity of phloem conductivity. We also review disease management strategies, including promising new technologies. Citrus production in the presence of Huanglongbing is possible if the most promising management approaches are integrated. HLB management is discussed in the context of local, area-wide, and regional Huanglongbing/Asian Citrus Psyllid epidemiological zones. For zebra chip disease control, aggressive psyllid management enables potato production, although insecticide resistance is becoming an issue. Meanwhile, new technologies such as clustered regularly interspaced short palindromic repeat (CRISPR)-derived genome editing provide an unprecedented opportunity to provide long-term solutions.
Collapse
Affiliation(s)
- Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, Florida 33850;
| | - Elizabeth A Pierson
- Department of Horticultural Sciences, Texas A&M University, College Station, Texas 77843
| | - João Carlos Setubal
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, 05508-000, Brazil
| | - Jin Xu
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, Florida 33850;
| | - Julien G Levy
- Department of Horticultural Sciences, Texas A&M University, College Station, Texas 77843
| | - Yunzeng Zhang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, Florida 33850;
| | - Jinyun Li
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Lake Alfred, Florida 33850;
| | - Luiz Thiberio Rangel
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, 05508-000, Brazil
| | - Joaquim Martins
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, 05508-000, Brazil
| |
Collapse
|
48
|
Psyllids, It’s What’s on the Inside That Counts: Community Cross Talk Facilitates Prophage Interactions. mSphere 2017; 2:mSphere00227-17. [PMID: 28612849 PMCID: PMC5463028 DOI: 10.1128/msphere.00227-17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Despite the availability of massive microbial community data sets (e.g., metagenomes), there is still a lack of knowledge on what molecular mechanisms facilitate cross talk between microbes and prophage within a community context. Despite the availability of massive microbial community data sets (e.g., metagenomes), there is still a lack of knowledge on what molecular mechanisms facilitate cross talk between microbes and prophage within a community context. A study published in mSphere by Jain and colleagues (M. Jain, L. A. Fleites, and D. W. Gabriel, mSphere 2:e00171-17, 2017, https://doi.org/10.1128/mSphereDirect.00171-17) reports on an intriguing new twist of how a prophage of the bacterium “Candidatus Liberibacter asiaticus” may have its lytic cycle suppressed partly because of a protein that is expressed by a cooccurring bacterium, Wolbachia. Both of these microbes coexist along with other microbial tenants inside their sap-feeding insect host, a psyllid. Although these results are still preliminary and alternative hypotheses need to be tested, these results suggest an interesting new dimension on how regulation of microbial genomes occurs in a community context.
Collapse
|
49
|
Zheng Z, Wu F, Kumagai LB, Polek M, Deng X, Chen J. Two 'Candidatus Liberibacter asiaticus' Strains Recently Found in California Harbor Different Prophages. PHYTOPATHOLOGY 2017; 107:662-668. [PMID: 28398165 DOI: 10.1094/phyto-10-16-0385-r] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
'Candidatus Liberibacter asiaticus' (CLas), an α-proteobacterium, is associated with citrus Huanglongbing (HLB; yellow shoot disease). In California, two cases of CLas have been detected in Los Angeles County, one in Hacienda Heights in 2012 and the other in San Gabriel in 2015. Although all infected trees were destroyed in compliance with a state mandate, citrus industry stakeholder concerns about HLB in California are high. Little is known about the biology of CLas, particularly the California strains, hindering effective HLB management efforts. In this study, next-generation sequencing technology (Illumina MiSeq) was employed to characterize the California CLas strains. Data sets containing >4 billion (Giga) bp of sequence were generated from each CLas sample. Two prophages (P-HHCA1-2 and P-SGCA5-1) were identified by the MiSeq read mapping technique referenced to two known Florida CLas prophage sequences, SC1 and SC2. P-HHCA1-2 was an SC2-like or Type 2 prophage of 38,989 bp in size. P-SGCA5-1 was an SC1-like or Type 1 prophage of 37,487 bp in size. Phylogenetic analysis revealed that P-HHCA1-2 was part of an Asiatic lineage within the Type 2 prophage group. Similarly, P-SGCA5-1 was part of an Asiatic lineage within Type 1 prophage group. The Asiatic relatedness of both P-HHCA1-2 and P-SGCA5-1 was further presented by single nucleotide polymorphism analysis at terL (encoding prophage terminase) that has been established for CLas strain differentiation. The presence of different prophages suggests that the two California CLas strains could have been introduced from different sources. An alternative explanation is that there was a mixed CLas population containing the two types of prophages, and limited sampling in a geographic region may not accurately depict the true CLas diversity. More accurate pathway analysis may be achieved by including more strains collected from the regions.
Collapse
Affiliation(s)
- Z Zheng
- First, second, and fifth authors: Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China; third author: Plant Pest Diagnostic Center, California Department of Food and Agriculture, Sacramento; fourth author: U.S. Department of Agriculture-Agriculture Research Services, National Clonal Germplasm Repository for Citrus and Dates, Riverside; and sixth author: San Joaquín Valley Agricultural Sciences Center, Parlier, CA
| | - F Wu
- First, second, and fifth authors: Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China; third author: Plant Pest Diagnostic Center, California Department of Food and Agriculture, Sacramento; fourth author: U.S. Department of Agriculture-Agriculture Research Services, National Clonal Germplasm Repository for Citrus and Dates, Riverside; and sixth author: San Joaquín Valley Agricultural Sciences Center, Parlier, CA
| | - L B Kumagai
- First, second, and fifth authors: Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China; third author: Plant Pest Diagnostic Center, California Department of Food and Agriculture, Sacramento; fourth author: U.S. Department of Agriculture-Agriculture Research Services, National Clonal Germplasm Repository for Citrus and Dates, Riverside; and sixth author: San Joaquín Valley Agricultural Sciences Center, Parlier, CA
| | - M Polek
- First, second, and fifth authors: Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China; third author: Plant Pest Diagnostic Center, California Department of Food and Agriculture, Sacramento; fourth author: U.S. Department of Agriculture-Agriculture Research Services, National Clonal Germplasm Repository for Citrus and Dates, Riverside; and sixth author: San Joaquín Valley Agricultural Sciences Center, Parlier, CA
| | - X Deng
- First, second, and fifth authors: Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China; third author: Plant Pest Diagnostic Center, California Department of Food and Agriculture, Sacramento; fourth author: U.S. Department of Agriculture-Agriculture Research Services, National Clonal Germplasm Repository for Citrus and Dates, Riverside; and sixth author: San Joaquín Valley Agricultural Sciences Center, Parlier, CA
| | - J Chen
- First, second, and fifth authors: Department of Plant Pathology, South China Agricultural University, Guangzhou, Guangdong, China; third author: Plant Pest Diagnostic Center, California Department of Food and Agriculture, Sacramento; fourth author: U.S. Department of Agriculture-Agriculture Research Services, National Clonal Germplasm Repository for Citrus and Dates, Riverside; and sixth author: San Joaquín Valley Agricultural Sciences Center, Parlier, CA
| |
Collapse
|
50
|
Jain M, Fleites LA, Gabriel DW. A Small Wolbachia Protein Directly Represses Phage Lytic Cycle Genes in " Candidatus Liberibacter asiaticus" within Psyllids. mSphere 2017; 2:e00171-17. [PMID: 28608866 PMCID: PMC5463029 DOI: 10.1128/mspheredirect.00171-17] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 04/20/2017] [Indexed: 01/17/2023] Open
Abstract
Huanglongbing (HLB) is a severe disease of citrus caused by an uncultured alphaproteobacterium "Candidatus Liberibacter asiaticus" and transmitted by Asian citrus psyllids (Diaphorina citri). Two prophage genomes, SC1 and SC2, integrated in "Ca. Liberibacter asiaticus" strain UF506 were described previously, and very similar prophages are found resident in the majority of "Ca. Liberibacter asiaticus" strains described worldwide. The SC1 lytic cycle is marked by upregulation of prophage late genes, including a functional holin (SC1_gp110); these late genes are activated when "Ca. Liberibacter asiaticus" is in planta, but not when infecting the psyllid host. We previously reported that the holin promoter is strongly and constitutively active in Liberibacter crescens (a cultured proxy for uncultured "Ca. Liberibacter asiaticus") but is suppressed in a dose-dependent manner by crude aqueous extracts from D. citri applied exogenously. Here we report that the suppressor activity of the crude psyllid extract was heat labile and abolished by proteinase K treatment, indicating a proteinaceous repressor and of a size smaller than 30 kDa. The repressor was affinity captured from D. citri aqueous extracts using biotinylated holin promoter DNA immobilized on magnetic beads and subjected to liquid chromatography-tandem mass spectrometry (LC-MS/MS). Protein database interrogation was used to identify a small DNA-binding protein encoded by a gene carried by Wolbachia strain wDi, a resident endosymbiont of D. citri as the repressor. The in vitro-translated Wolbachia repressor protein was able to penetrate L. crescens cells, bind to "Ca. Liberibacter asiaticus" promoter DNA, and partially suppress holin promoter-driven β-glucuronidase (GUS) activity, indicating potential involvement of an additional interacting partner(s) or posttranslational modification(s) for complete suppression. Expression of the Wolbachia repressor protein appeared to be constitutive irrespective of "Ca. Liberibacter asiaticus" infection status of the insect host. IMPORTANCE Host acquisition of a new microbial species can readily perturb the dynamics of preexisting microbial associations. Molecular cross talk between microbial associates may be necessary for efficient resource allocation and enhanced survival. Classic examples involve quorum sensing (QS), which detects population densities and is both used and coopted to control expression of bacterial genes, including host adaptation factors. We report that a 56-amino-acid repressor protein made by the resident psyllid endosymbiont Wolbachia can enter cells of Liberibacter crescens, a cultured proxy for the uncultured psyllid endosymbiont "Ca. Liberibacter asiaticus" and repress "Ca. Liberibacter asiaticus" phage lytic cycle genes. Such repression in "Ca. Liberibacter asiaticus" may be critical to survival of both endosymbionts, since phage-mediated lysis would likely breach the immunogenic threshold of the psyllid, invoking a systemic and nonspecific innate immune reaction.
Collapse
Affiliation(s)
- Mukesh Jain
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Laura A Fleites
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Dean W Gabriel
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| |
Collapse
|