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Li F, Deng J, Zhang Z, Wang C, Mao Y. FabV, the Unique Enoyl-Acyl Carrier Protein Reductase in Xanthomonas arboricola pv. juglandis Associated with Walnut Bacterial Blight, Is Essential for the Growth and Confers Triclosan Resistance to the Strain. PHYTOPATHOLOGY 2024; 114:780-791. [PMID: 37913555 DOI: 10.1094/phyto-08-23-0272-r] [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: 11/03/2023]
Abstract
Walnut bacterial blight caused by Xanthomonas arboricola pv. juglandis (Xaj) is one of the most prevalent diseases of walnut (Juglans spp.), causing significant reductions in nut yield and important losses in economy. Enoyl-acyl carrier protein (ACP) reductase (ENR) is one of the key enzymes involved in the biosynthesis of bacterial fatty acids. In this study, we identified a single ENR-encoding gene, RS10040, in the genome of the XajDW3F3 strain. Sequence alignment analysis suggested RS10040 as a candidate fabV gene in Xaj. Expression of XajfabV restored the growth of the Escherichia coli fabI temperature-sensitive mutant under a nonpermissive growth condition. In vitro assays demonstrated that XajFabV catalyzed enoyl-ACPs of various chain lengths to acyl-ACPs, demonstrating its role in de novo fatty acid biosynthesis. Furthermore, we confirmed that XajfabV is an essential gene for growth, as no XajfabV deletion mutant could be obtained, although XajfabV in the chromosome could be deleted after compensating with a functional ENR-encoding gene via an exogenous plasmid. The fabV replacement mutants showed similar growth characteristic and fatty acid compositions. Our data further identified that fabV conferred Xaj with tolerance to various environmental stresses. Although XajFabV conferred Xaj with triclosan resistance, the resistance of Xaj was weaker than that found for Pseudomonas aeruginosa. Moreover, triclosan exhibited a control effect against infection of the ΔfabV/EcfabI to its host walnut. This study revealed the function of XajFabV and laid a theoretical foundation for the fatty acid synthesis mechanism of Xaj.
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Affiliation(s)
- Feng Li
- Hubei Key Laboratory of Quality Control of Characteristic Fruits and Vegetables/College of Life Science and Technology, Hubei Engineering University, Xiaogan 432000, China
| | - Jiangli Deng
- Hubei Key Laboratory of Quality Control of Characteristic Fruits and Vegetables/College of Life Science and Technology, Hubei Engineering University, Xiaogan 432000, China
| | - Zhilin Zhang
- Hubei Key Laboratory of Quality Control of Characteristic Fruits and Vegetables/College of Life Science and Technology, Hubei Engineering University, Xiaogan 432000, China
| | - Cheng Wang
- Hubei Key Laboratory of Quality Control of Characteristic Fruits and Vegetables/College of Life Science and Technology, Hubei Engineering University, Xiaogan 432000, China
| | - Yahui Mao
- Hubei Key Laboratory of Quality Control of Characteristic Fruits and Vegetables/College of Life Science and Technology, Hubei Engineering University, Xiaogan 432000, China
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Guo Q, Su J, Liao Y, Yu Y, Luo L, Weng X, Zhang W, Hu Z, Wang H, Beattie GA, Ma J. An atypical 3-ketoacyl ACP synthase III required for acyl homoserine lactone synthesis in Pseudomonas syringae pv. syringae B728a. Appl Environ Microbiol 2024; 90:e0225623. [PMID: 38415624 PMCID: PMC10952384 DOI: 10.1128/aem.02256-23] [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: 12/13/2023] [Accepted: 02/04/2024] [Indexed: 02/29/2024] Open
Abstract
The last step of the initiation phase of fatty acid biosynthesis in most bacteria is catalyzed by the 3-ketoacyl-acyl carrier protein (ACP) synthase III (FabH). Pseudomonas syringae pv. syringae strain B728a encodes two FabH homologs, Psyr_3467 and Psyr_3830, which we designated PssFabH1 and PssFabH2, respectively. Here, we explored the roles of these two 3-ketoacyl-ACP synthase (KAS) III proteins. We found that PssFabH1 is similar to the Escherichia coli FabH in using acetyl-acetyl-coenzyme A (CoA ) as a substrate in vitro, whereas PssFabH2 uses acyl-CoAs (C4-C10) or acyl-ACPs (C6-C10). Mutant analysis showed that neither KAS III protein is essential for the de novo fatty acid synthesis and cell growth. Loss of PssFabH1 reduced the production of an acyl homoserine lactone (AHL) quorum-sensing signal, and this production was partially restored by overexpressing FabH homologs from other bacteria. AHL production was also restored by inhibiting fatty acid elongation and providing exogenous butyric acid. Deletion of PssFabH1 supports the redirection of acyl-ACP toward biosurfactant synthesis, which in turn enhances swarming motility. Our study revealed that PssFabH1 is an atypical KAS III protein that represents a new KAS III clade that functions in providing a critical fatty acid precursor, butyryl-ACP, for AHL synthesis.IMPORTANCEAcyl homoserine lactones (AHLs) are important quorum-sensing compounds in Gram-negative bacteria. Although their formation requires acylated acyl carrier proteins (ACPs), how the acylated intermediate is shunted from cellular fatty acid synthesis to AHL synthesis is not known. Here, we provide in vivo evidence that Pseudomonas syringae strain B728a uses the enzyme PssFabH1 to provide the critical fatty acid precursor butyryl-ACP for AHL synthesis. Loss of PssFabH1 reduces the diversion of butyryl-ACP to AHL, enabling the accumulation of acyl-ACP for synthesis of biosurfactants that contribute to bacterial swarming motility. We report that PssFabH1 and PssFabH2 each encode a 3-ketoacyl-acyl carrier protein synthase (KAS) III in P. syringae B728a. Whereas PssFabH2 is able to function in redirecting intermediates from β-oxidation to fatty acid synthesis, PssFabH1 is an atypical KAS III protein that represents a new KAS III clade based on its sequence, non-involvement in cell growth, and novel role in AHL synthesis.
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Affiliation(s)
- Qiaoqiao Guo
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Jingtong Su
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Yuling Liao
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Yin Yu
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Lizhen Luo
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Xiaoshan Weng
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Wenbin Zhang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Zhe Hu
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Haihong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
| | - Gwyn A. Beattie
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, Iowa, USA
| | - Jincheng Ma
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong, China
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, Iowa, USA
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Xia K, Feng Z, Zhang X, Zhou Y, Zhu H, Yao Q. Potential functions of the shared bacterial taxa in the citrus leaf midribs determine the symptoms of Huanglongbing. FRONTIERS IN PLANT SCIENCE 2023; 14:1270929. [PMID: 38034569 PMCID: PMC10682189 DOI: 10.3389/fpls.2023.1270929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 10/30/2023] [Indexed: 12/02/2023]
Abstract
Instruction Citrus is a globally important fruit tree whose microbiome plays a vital role in its growth, adaptability, and resistance to stress. Methods With the high throughput sequencing of 16S rRNA genes, this study focused on analyzing the bacterial community, especially in the leaf midribs, of healthy and Huanglongbing (HLB)-infected plants. Results We firstly identified the shared bacterial taxa in the midribs of both healthy and HLB-infected plants, and then analyzed their functions. Results showed that the shared bacterial taxa in midribs belonged to 62 genera, with approximately 1/3 of which modified in the infected samples. Furthermore, 366 metabolic pathways, 5851 proteins, and 1833 enzymes in the shared taxa were predicted. Among these, three metabolic pathways and one protein showed significant importance in HLB infection. With the random forest method, six genera were identified to be significantly important for HLB infection. Notably, four of these genera were also among the significantly different shared taxa. Further functional characterization of these four genera revealed that Pseudomonas and Erwinia likely contributed to plant defense against HLB, while Streptomyces might have implications for plant defense against HLB or the pathogenicity of Candidatus Liberibacter asiaticus (CLas). Disccusion Overall, our study highlights that the functions of the shared taxa in leaf midribs are distinguished between healthy and HLB-infected plants, and these microbiome-based findings can contribute to the management and protection of citrus crops against CLas.
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Affiliation(s)
- Kaili Xia
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China), Ministry of Agriculture and Rural Affairs, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Horticulture, South China Agricultural University, Guangzhou, China
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Zengwei Feng
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Xianjiao Zhang
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China), Ministry of Agriculture and Rural Affairs, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Horticulture, South China Agricultural University, Guangzhou, China
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Yang Zhou
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Honghui Zhu
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Qing Yao
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China), Ministry of Agriculture and Rural Affairs, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Horticulture, South China Agricultural University, Guangzhou, China
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Yu YH, Chen C, Ma JR, Zhang YY, Yan MF, Zhang WB, Hu Z, Wang HH, Ma JC. The FabA-FabB Pathway Is Not Essential for Unsaturated Fatty Acid Synthesis but Modulates Diffusible Signal Factor Synthesis in Xanthomonas campestris pv. campestris. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2023; 36:119-130. [PMID: 36515967 DOI: 10.1094/mpmi-09-22-0182-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Most bacteria use type II fatty acid synthesis (FAS) systems for synthesizing fatty acids, of which the conserved FabA-FabB pathway is considered to be crucial for unsaturated fatty acid (UFA) synthesis in gram-negative bacteria. Xanthomonas campestris pv. campestris, the phytopathogen of black rot disease in crucifers, produces higher quantities of UFAs under low-temperature conditions for increasing membrane fluidity. The fabA and fabB genes were identified in the X. campestris pv. campestris genome by BLAST analysis; however, the growth of the X. campestris pv. campestris fabA and fabB deletion mutants was comparable to that of the wild-type strain in nutrient and minimal media. The X. campestris pv. campestris ΔfabA and ΔfabB strains produced large quantities of UFAs and, altogether, these results indicated that the FabA-FabB pathway is not essential for growth or UFA synthesis in X. campestris pv. campestris. We also observed that the expression of X. campestris pv. campestris fabA and fabB restored the growth of the temperature-sensitive Escherichia coli fabA and fabB mutants CL104 and CY242, respectively, under non-permissive conditions. The in-vitro assays demonstrated that the FabA and FabB proteins of X. campestris pv. campestris catalyzed FAS. Our study also demonstrated that the production of diffusible signal factor family signals that mediate quorum sensing was higher in the X. campestris pv. campestris ΔfabA and ΔfabB strains and greatly reduced in the complementary strains, which exhibited reduced swimming motility and attenuated host-plant pathogenicity. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Yong-Hong Yu
- Guangdong Food and Drug Vocational College, Guangzhou, Guangdong 510520, China
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Cheng Chen
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Jian-Rong Ma
- Guangdong Food and Drug Vocational College, Guangzhou, Guangdong 510520, China
| | - Yuan-Yin Zhang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Ming-Feng Yan
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Wen-Bin Zhang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Zhe Hu
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Hai-Hong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Jin-Cheng Ma
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
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Chowdhury NB, Alsiyabi A, Saha R. Characterizing the Interplay of Rubisco and Nitrogenase Enzymes in Anaerobic-Photoheterotrophically Grown Rhodopseudomonas palustris CGA009 through a Genome-Scale Metabolic and Expression Model. Microbiol Spectr 2022; 10:e0146322. [PMID: 35730964 PMCID: PMC9431616 DOI: 10.1128/spectrum.01463-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 05/31/2022] [Indexed: 11/20/2022] Open
Abstract
Rhodopseudomonas palustris CGA009 is a Gram-negative purple nonsulfur bacterium that grows phototrophically by fixing carbon dioxide and nitrogen or chemotrophically by fixing or catabolizing a wide array of substrates, including lignin breakdown products for its carbon and fixing nitrogen for its nitrogen requirements. It can grow aerobically or anaerobically and can use light, inorganic, and organic compounds for energy production. Due to its ability to convert different carbon sources into useful products during anaerobic growth, this study reconstructed a metabolic and expression (ME) model of R. palustris to investigate its anaerobic-photoheterotrophic growth. Unlike metabolic (M) models, ME models include transcription and translation reactions along with macromolecules synthesis and couple these reactions with growth rate. This unique feature of the ME model led to nonlinear growth curve predictions, which matched closely with experimental growth rate data. At the theoretical maximum growth rate, the ME model suggested a diminishing rate of carbon fixation and predicted malate dehydrogenase and glycerol-3 phosphate dehydrogenase as alternate electron sinks. Moreover, the ME model also identified ferredoxin as a key regulator in distributing electrons between major redox balancing pathways. Because ME models include the turnover rate for each metabolic reaction, it was used to successfully capture experimentally observed temperature regulation of different nitrogenases. Overall, these unique features of the ME model demonstrated the influence of nitrogenases and rubiscos on R. palustris growth and predicted a key regulator in distributing electrons between major redox balancing pathways, thus establishing a platform for in silico investigation of R. palustris metabolism from a multiomics perspective. IMPORTANCE In this work, we reconstructed the first ME model for a purple nonsulfur bacterium (PNSB). Using the ME model, different aspects of R. palustris metabolism were examined. First, the ME model was used to analyze how reducing power entering the R. palustris cell through organic carbon sources gets partitioned into biomass, carbon dioxide fixation, and nitrogen fixation. Furthermore, the ME model predicted electron flux through ferredoxin as a major bottleneck in distributing electrons to nitrogenase enzymes. Next, the ME model characterized different nitrogenase enzymes and successfully recapitulated experimentally observed temperature regulations of those enzymes. Identifying the bottleneck responsible for transferring an electron to nitrogenase enzymes and recapitulating the temperature regulation of different nitrogenase enzymes can have profound implications in metabolic engineering, such as hydrogen production from R. palustris. Another interesting application of this ME model can be to take advantage of its redox balancing strategy to gain an understanding of the regulatory mechanism of biodegradable plastic production precursors, such as polyhydroxybutyrate (PHB).
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Affiliation(s)
- Niaz Bahar Chowdhury
- Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Adil Alsiyabi
- Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Rajib Saha
- Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
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Chen YC, Hu Z, Zhang WB, Yin Y, Zhong CY, Mo WY, Yu YH, Ma JC, Wang HH. HetI-Like Phosphopantetheinyl Transferase Posttranslationally Modifies Acyl Carrier Proteins in Xanthomonas spp. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2022; 35:323-335. [PMID: 35286156 DOI: 10.1094/mpmi-10-21-0249-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In Xanthomonas spp., the biosynthesis of the yellow pigment xanthomonadin and fatty acids originates in the type II polyketide synthase (PKS II) and fatty acid synthase (FAS) pathways, respectively. The acyl carrier protein (ACP) is the central component of PKS II and FAS and requires posttranslational phosphopantetheinylation to initiate these pathways. In this study, for the first time, we demonstrate that the posttranslational modification of ACPs in X. campestris pv. campestris is performed by an essential 4'-phosphopantetheinyl transferase (PPTase), XcHetI (encoded by Xc_4132). X. campestris pv. campestris strain XchetI could not be deleted from the X. campestris pv. campestris genome unless another PPTase-encoding gene such as Escherichia coli acpS or Pseudomonas aeruginosa pcpS was present. Compared with wild-type strain X. campestris pv. campestris 8004 and mutant XchetI::PapcpS, strain XchetI::EcacpS failed to generate xanthomonadin pigments and displayed reduced pathogenicity for the host plant, Brassica oleracea. Further experiments showed that the expression of XchetI restored the growth of E. coli acpS mutant HT253 and, when a plasmid bearing XchetI was introduced into P. aeruginosa, pcpS, which encodes the sole PPTase in P. aeruginosa, could be deleted. In in vitro enzymatic assays, XcHetI catalyzed the transformation of 4'-phosphopantetheine from coenzyme A to two X. campestris pv. campestris apo-acyl carrier proteins, XcAcpP and XcAcpC. All of these findings indicate that XcHetI is a surfactin PPTase-like PPTase with a broad substrate preference. Moreover, the HetI-like PPTase is ubiquitously conserved in Xanthomonas spp., making it a potential new drug target for the prevention of plant diseases caused by Xanthomonas.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Yi-Cai Chen
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Zhe Hu
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Wen-Bin Zhang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Yu Yin
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Can-Yao Zhong
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Wan-Ying Mo
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Yong-Hong Yu
- Guangdong Food and Drug Vocational College, Guangzhou, Guangdong 510520, China
| | - Jin-Cheng Ma
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Hai-Hong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
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Insights into Acinetobacter baumannii fatty acid synthesis 3-oxoacyl-ACP reductases. Sci Rep 2021; 11:7050. [PMID: 33782435 PMCID: PMC8007833 DOI: 10.1038/s41598-021-86400-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 03/08/2021] [Indexed: 11/08/2022] Open
Abstract
Treatments for 'superbug' infections are the focus for innovative research, as drug resistance threatens human health and medical practices globally. In particular, Acinetobacter baumannii (Ab) infections are repeatedly reported as difficult to treat due to increasing antibiotic resistance. Therefore, there is increasing need to identify novel targets in the development of different antimicrobials. Of particular interest is fatty acid synthesis, vital for the formation of phospholipids, lipopolysaccharides/lipooligosaccharides, and lipoproteins of Gram-negative envelopes. The bacterial type II fatty acid synthesis (FASII) pathway is an attractive target for the development of inhibitors and is particularly favourable due to the differences from mammalian type I fatty acid synthesis. Discrete enzymes in this pathway include two reductase enzymes: 3-oxoacyl-acyl carrier protein (ACP) reductase (FabG) and enoyl-ACP reductase (FabI). Here, we investigate annotated FabG homologs, finding a low-molecular weight 3-oxoacyl-ACP reductase, as the most likely FASII FabG candidate, and high-molecular weight 3-oxoacyl-ACP reductase (HMwFabG), showing differences in structure and coenzyme preference. To date, this is the second bacterial high-molecular weight FabG structurally characterized, following FabG4 from Mycobacterium. We show that ΔAbHMwfabG is impaired for growth in nutrient rich media and pellicle formation. We also modelled a third 3-oxoacyl-ACP reductase, which we annotated as AbSDR. Despite containing residues for catalysis and the ACP coordinating motif, biochemical analyses showed limited activity against an acetoacetyl-CoA substrate in vitro. Inhibitors designed to target FabG proteins and thus prevent fatty acid synthesis may provide a platform for use against multidrug-resistant pathogens including A. baumannii.
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An SQ, Potnis N, Dow M, Vorhölter FJ, He YQ, Becker A, Teper D, Li Y, Wang N, Bleris L, Tang JL. Mechanistic insights into host adaptation, virulence and epidemiology of the phytopathogen Xanthomonas. FEMS Microbiol Rev 2020; 44:1-32. [PMID: 31578554 PMCID: PMC8042644 DOI: 10.1093/femsre/fuz024] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 09/29/2019] [Indexed: 01/15/2023] Open
Abstract
Xanthomonas is a well-studied genus of bacterial plant pathogens whose members cause a variety of diseases in economically important crops worldwide. Genomic and functional studies of these phytopathogens have provided significant understanding of microbial-host interactions, bacterial virulence and host adaptation mechanisms including microbial ecology and epidemiology. In addition, several strains of Xanthomonas are important as producers of the extracellular polysaccharide, xanthan, used in the food and pharmaceutical industries. This polymer has also been implicated in several phases of the bacterial disease cycle. In this review, we summarise the current knowledge on the infection strategies and regulatory networks controlling virulence and adaptation mechanisms from Xanthomonas species and discuss the novel opportunities that this body of work has provided for disease control and plant health.
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Affiliation(s)
- Shi-Qi An
- National Biofilms Innovation Centre (NBIC), Biological Sciences, University of Southampton, University Road, Southampton SO17 1BJ, UK
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Rouse Life Science Building, Auburn University, Auburn AL36849, USA
| | - Max Dow
- School of Microbiology, Food Science & Technology Building, University College Cork, Cork T12 K8AF, Ireland
| | | | - Yong-Qiang He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning 530004, Guangxi, China
| | - Anke Becker
- Loewe Center for Synthetic Microbiology and Department of Biology, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, Marburg 35032, Germany
| | - Doron Teper
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred 33850, USA
| | - Yi Li
- Bioengineering Department, University of Texas at Dallas, 2851 Rutford Ave, Richardson, TX 75080, USA.,Center for Systems Biology, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX 75080, USA
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred 33850, USA
| | - Leonidas Bleris
- Bioengineering Department, University of Texas at Dallas, 2851 Rutford Ave, Richardson, TX 75080, USA.,Center for Systems Biology, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX 75080, USA.,Department of Biological Sciences, University of Texas at Dallas, 800 W Campbell Road, Richardson, TX75080, USA
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning 530004, Guangxi, China
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Li K, Wu G, Liao Y, Zeng Q, Wang H, Liu F. RpoN1 and RpoN2 play different regulatory roles in virulence traits, flagellar biosynthesis, and basal metabolism in Xanthomonas campestris. MOLECULAR PLANT PATHOLOGY 2020; 21:907-922. [PMID: 32281725 PMCID: PMC7280030 DOI: 10.1111/mpp.12938] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/18/2020] [Accepted: 03/18/2020] [Indexed: 05/08/2023]
Abstract
Homologous regulatory factors are widely present in bacteria, but whether homologous regulators synergistically or differentially regulate different biological functions remains mostly unknown. Here, we report that the homologous regulators RpoN1 and RpoN2 of the plant pathogen Xanthomonas campestris pv. campestris (Xcc) play different regulatory roles with respect to virulence traits, flagellar biosynthesis, and basal metabolism. RpoN2 directly regulated Xcc fliC and fliQ to modulate flagellar synthesis in X. campestris, thus affecting the swimming motility of X. campestris. Mutation of rpoN2 resulted in reduced production of biofilms and extracellular polysaccharides in Xcc. These defects may together cause reduced virulence of the rpoN2 mutant against the host plant. Moreover, we demonstrated that RpoN1 could regulate branched-chain fatty acid production and modulate the synthesis of diffusible signal factor family quorum sensing signals. Although RpoN1 and RpoN2 are homologues, the regulatory roles and biological functions of these proteins were not interchangeable. Overall, our report provides new insights into the two different molecular roles that form the basis for the transcriptional specialization of RpoN homologues.
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Affiliation(s)
- Kaihuai Li
- College of Plant ProtectionNanjing Agricultural UniversityNanjingChina
| | - Guichun Wu
- Institute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjingChina
| | - Yuling Liao
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouChina
| | - Quan Zeng
- Department of Plant Pathology and EcologyThe Connecticut Agricultural Experiment StationNew HavenCTUSA
| | - Haihong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouChina
| | - Fengquan Liu
- College of Plant ProtectionNanjing Agricultural UniversityNanjingChina
- Institute of Plant ProtectionJiangsu Academy of Agricultural SciencesNanjingChina
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10
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He YU, Wang S, Yin X, Sun F, He B, Liu X. Comparison of Extracellular Proteins from Virulent and Avirulent Vibrio parahaemolyticus Strains To Identify Potential Virulence Factors. J Food Prot 2020; 83:155-162. [PMID: 31860395 DOI: 10.4315/0362-028x.jfp-19-188] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Vibrio parahaemolyticus is a leading seafood-borne pathogen that causes gastroenteritis, septicemia, and serious wound infections due to the actions of virulence-associated proteins. We compared the extracellular proteins of nonvirulent JHY20 and virulent ATCC 33847 V. parahaemolyticus reference strains. Eighteen extracellular proteins were identified from secretory profiles, and 11 (68.75%) of the 16 proteins in ATCC 33847 are associated with virulence and/or protection against adverse conditions: trigger factor, chaperone SurA, aspartate-semialdehyde dehydrogenase, 4-hydroxy-3-methylbut-2-en-1-yl diphosphate synthase, glutamate 5-kinase, alanine dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, outer membrane protein OmpV, ribosome-associated inhibitor A, chaperone protein Skp, and universal stress protein. Two nontoxic-related proteins, amino acid ABC transporter substrate-binding protein and an uncharacterized protein, were identified in JHY20. The results provide a theoretical basis for supporting safety risk assessment of aquatic foods, illuminate the pathogenic mechanisms of V. parahaemolyticus, and assist the identification of novel vaccine candidates for foodborne pathogens.
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Affiliation(s)
- Y U He
- College of Food (Biotechnology) Engineering.,Key Construction Laboratory of Food Resources Development and the Quality Safety, Xuzhou University of Technology, Jiangsu, Xuzhou 221018, People's Republic of China
| | - Shuai Wang
- College of Food (Biotechnology) Engineering.,Key Construction Laboratory of Food Resources Development and the Quality Safety, Xuzhou University of Technology, Jiangsu, Xuzhou 221018, People's Republic of China
| | | | - Fengjiao Sun
- Logistics & Security Department, Shanghai Civil Aviation College, Shanghai 201300, People's Republic of China
| | - Bin He
- Environment Monitoring Station, Zaozhuang Municipal Bureau of Ecology and Environment, Shandong 277100, People's Republic of China
| | - Xiao Liu
- Henan Key Laboratory of Cold Chain Food Quality and Safety Control, Zhengzhou University of Light Industry, Zhengzhou 450001, People's Republic of China
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11
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Yu Y, Ma J, Guo Q, Ma J, Wang H. A novel 3-oxoacyl-ACP reductase (FabG3) is involved in the xanthomonadin biosynthesis of Xanthomonas campestris pv. campestris. MOLECULAR PLANT PATHOLOGY 2019; 20:1696-1709. [PMID: 31560825 PMCID: PMC6859482 DOI: 10.1111/mpp.12871] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Xanthomonas campestris pv. campestris (Xcc), the causal agent of black rot in crucifers, produces a membrane-bound yellow pigment called xanthomonadin to protect against photobiological and peroxidative damage, and uses a quorum-sensing mechanism mediated by the diffusible signal factor (DSF) family signals to regulate virulence factors production. The Xcc gene XCC4003, annotated as Xcc fabG3, is located in the pig cluster, which may be responsible for xanthomonadin synthesis. We report that fabG3 expression restored the growth of the Escherichia coli fabG temperature-sensitive mutant CL104 under non-permissive conditions. In vitro assays demonstrated that FabG3 catalyses the reduction of 3-oxoacyl-acyl carrier protein (ACP) intermediates in fatty acid synthetic reactions, although FabG3 had a lower activity than FabG1. Moreover, the fabG3 deletion did not affect growth or fatty acid composition. These results indicate that Xcc fabG3 encodes a 3-oxoacyl-ACP reductase, but is not essential for growth or fatty acid synthesis. However, the Xcc fabG3 knock-out mutant abolished xanthomonadin production, which could be only restored by wild-type fabG3, but not by other 3-oxoacyl-ACP reductase-encoding genes, indicating that Xcc FabG3 is specifically involved in xanthomonadin biosynthesis. Additionally, our study also shows that the Xcc fabG3-disrupted mutant affects Xcc virulence in host plants.
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Affiliation(s)
- Yonghong Yu
- Guangdong Food and Drug Vocational CollegeGuangzhouGuangdong510520China
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouGuangdong510642China
| | - Jianrong Ma
- Guangdong Food and Drug Vocational CollegeGuangzhouGuangdong510520China
| | - Qiaoqiao Guo
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouGuangdong510642China
| | - Jincheng Ma
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouGuangdong510642China
| | - Haihong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural OrganismsCollege of Life SciencesSouth China Agricultural UniversityGuangzhouGuangdong510642China
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12
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Potnis N, Kandel PP, Merfa MV, Retchless AC, Parker JK, Stenger DC, Almeida RPP, Bergsma-Vlami M, Westenberg M, Cobine PA, De La Fuente L. Patterns of inter- and intrasubspecific homologous recombination inform eco-evolutionary dynamics of Xylella fastidiosa. THE ISME JOURNAL 2019; 13:2319-2333. [PMID: 31110262 PMCID: PMC6776109 DOI: 10.1038/s41396-019-0423-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 04/05/2019] [Accepted: 04/09/2019] [Indexed: 11/09/2022]
Abstract
High rates of homologous recombination (HR) in the bacterial plant pathogen Xylella fastidiosa have been previously detected. This study aimed to determine the extent and explore the ecological significance of HR in the genomes of recombinants experimentally generated by natural transformation and wild-type isolates. Both sets of strains displayed widespread HR and similar average size of recombined fragments consisting of random events (2-10 kb) of inter- and intrasubspecific recombination. A significantly higher proportion and greater lengths (>10 kb, maximum 31.5 kb) of recombined fragments were observed in subsp. morus and in strains isolated in Europe from intercepted coffee plants shipped from the Americas. Such highly recombinant strains pose a serious risk of emergence of novel variants, as genetically distinct and formerly geographically isolated genotypes are brought in close proximity by global trade. Recently recombined regions in wild-type strains included genes involved in regulation and signaling, host colonization, nutrient acquisition, and host evasion, all fundamental traits for X. fastidiosa ecology. Identification of four recombinant loci shared between wild-type and experimentally generated recombinants suggests potential hotspots of recombination in this naturally competent pathogen. These findings provide insights into evolutionary forces possibly affecting the adaptive potential to colonize the host environments of X. fastidiosa.
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Affiliation(s)
- Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, 209 Rouse Life Sciences Bldg, Auburn, AL, USA
| | - Prem P Kandel
- Department of Entomology and Plant Pathology, Auburn University, 209 Rouse Life Sciences Bldg, Auburn, AL, USA
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA, USA
| | - Marcus V Merfa
- Department of Entomology and Plant Pathology, Auburn University, 209 Rouse Life Sciences Bldg, Auburn, AL, USA
| | - Adam C Retchless
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
- Meningitis and Vaccine Preventable Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Jennifer K Parker
- Department of Entomology and Plant Pathology, Auburn University, 209 Rouse Life Sciences Bldg, Auburn, AL, USA
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Drake C Stenger
- United States Department of Agriculture-Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA, USA
| | - Rodrigo P P Almeida
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
| | - Maria Bergsma-Vlami
- Dutch National Plant Protection Organization (NPPO-NL), P.O. Box. 9102, Wageningen, 6700 HC, The Netherlands
| | - Marcel Westenberg
- Dutch National Plant Protection Organization (NPPO-NL), P.O. Box. 9102, Wageningen, 6700 HC, The Netherlands
| | - Paul A Cobine
- Department of Biological Sciences, Auburn University, Auburn, AL, USA
| | - Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, 209 Rouse Life Sciences Bldg, Auburn, AL, USA.
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13
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Guo QQ, Zhang WB, Zhang C, Song YL, Liao YL, Ma JC, Yu YH, Wang HH. Characterization of 3-Oxacyl-Acyl Carrier Protein Reductase Homolog Genes in Pseudomonas aeruginosa PAO1. Front Microbiol 2019; 10:1028. [PMID: 31231314 PMCID: PMC6558427 DOI: 10.3389/fmicb.2019.01028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 04/24/2019] [Indexed: 12/19/2022] Open
Abstract
Bacterial 3-oxoacyl-ACP reductase (OAR) catalyzes the 3-oxoacyl-ACP reduction step in the fatty acid synthesis pathway. At least 12 genes in the Pseudomonas aeruginosa genome are annotated as OAR-encoding genes. In this study, we characterized the functions of these genes with biochemical and genetic techniques. With the exception of PA2967, which encodes FabG, an essential protein in fatty acid synthesis, only the PA4389 and PA4786 gene products had OAR activity, and the single deletion of these two genes reduced the ability of P. aeruginosa to produce several specific quorum-sensing (QS) signals. However, PA4389 and PA4786 do not have key roles in fatty acid synthesis. Moreover, although most OAR homologs had no OAR activity, some may function in carbon utilization. The PA3128 product may play a role in the TCA cycle, and PA0182 and PA1470 seem to be required for the utilization of several amino acids. The rest of the OAR homologs have no roles in carbon utilization, but the deletion of one of these genes might affect the production of virulence factors by P. aeruginosa. We conclude that most OAR homolog genes do not encode OAR enzymes, and that these proteins do not function in fatty acid synthesis.
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Affiliation(s)
- Qiao-Qiao Guo
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Wen-Bin Zhang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Chao Zhang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Yu-Lu Song
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Yu-Ling Liao
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Jin-Cheng Ma
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Yong-Hong Yu
- Guangdong Food and Drug Vocational College, Guangzhou, China
| | - Hai-Hong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, China
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14
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Genome sequence of Xanthomonas fuscans subsp. fuscans strain Xff49: a new isolate obtained from common beans in Southern Brazil. Braz J Microbiol 2019; 50:357-367. [PMID: 30850979 DOI: 10.1007/s42770-019-00050-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 01/21/2019] [Indexed: 01/22/2023] Open
Abstract
The genus Xanthomonas comprises Gram-negative bacteria, many of which are phytopathogens. Xanthomonas fuscans subsp. fuscans is one of the most devastating pathogens affecting the bean plant, resulting in the common bacterial blight of bean (CBB). The disease is mainly foliar and affects a wide variety of bean species, thus acting as the yield-limiting factor for the bean crop. Here, we report the whole-genome sequencing of a new strain of X. fuscans subsp. fuscans, named Xff49, isolated from the infected and symptomatic beans from Capão do Leão, Southern Brazil. The genetic analysis demonstrated the presence of single-nucleotide variants (SNVs) in this strain, potentially affecting the mobilome, cell mobility, and inorganic ion metabolism. In addition, the analysis resulted in the identification of a new plasmid similar to the pAX22 derived from Achromobacter denitrificans, which was named plX, along with plA and plC, previously reported in other strains of X. fuscans subsp. fuscans. Xff49 represents the first Brazilian genome of X. fuscans subsp. fuscans and might provide useful information applicable to the studies of phylogenetics, evolution, and pathogenomics, thereby allowing a better understanding of the genomic features present in the Brazilian strains.
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15
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Diab AA, Cao XQ, Chen H, Song K, Zhou L, Chen B, He YW. BDSF Is the Predominant In-Planta Quorum-Sensing Signal Used During Xanthomonas campestris Infection and Pathogenesis in Chinese Cabbage. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:240-254. [PMID: 30570452 DOI: 10.1094/mpmi-07-18-0197-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Xanthomonas campestris pv. campestris uses the diffusible signal factor (DSF) family of quorum-sensing (QS) signals to coordinate virulence and adaptation. DSF family signals have been well-characterized using laboratory-based cell cultures. The in-planta QS signal used during X. campestris pv. campestris infection remains unclear. To achieve this goal, we first mimic in-planta X. campestris pv. campestris growth conditions by supplementing the previously developed XYS medium with cabbage hydrolysate and found that the dominant signal produced in these conditions was BDSF. Secondly, by using XYS medium supplemented with diverse plant-derived compounds, we examined the effects of diverse plant-derived compounds on the biosynthesis of DSF family signals. Several compounds were found to promote biosynthesis of BDSF. Finally, using an X. campestris pv. campestris ΔrpfB-Chinese cabbage infection model and an ultra-performance liquid chromatographic-time of flight-mass spectrometry-based assay, BDSF was found to comprise >70% of the DSF family signals present in infected cabbage tissue. BDSF at a concentration of 2.0 μM induced both protease activity and engXCA expression. This is the first report to directly show that BDSF is the predominant in-planta QS signal used during X. campestris pv. campestris infection. It provides a better understanding of the molecular interactions between X. campestris pv. campestris and its cruciferous hosts and also provides the logical target for designing strategies to counteract BDSF signaling and, thus, infection. Further studies are needed to get an exact idea about the DSF production dynamics of the wild-type strain inside the plant.
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Affiliation(s)
- Abdelgader Abdeen Diab
- 1 State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; and
| | - Xue-Qiang Cao
- 1 State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; and
| | - Hui Chen
- 1 State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; and
| | - Kai Song
- 1 State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; and
| | - Lian Zhou
- 2 Zhiyuan Innovation Research Centre, Student Innovation Centre, Zhiyuan College, Shanghai Jiao Tong University
| | - Bo Chen
- 1 State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; and
| | - Ya-Wen He
- 1 State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; and
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