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Gordon MI, Thomas WJ, Putnam ML. Transmission and Management of Pathogenic Agrobacterium tumefaciens and Rhodococcus fascians in Select Ornamentals. PLANT DISEASE 2024; 108:50-61. [PMID: 37368442 DOI: 10.1094/pdis-11-22-2557-re] [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: 06/28/2023]
Abstract
Pathogenic Agrobacterium tumefaciens and Rhodococcus fascians are phytobacteria that induce crown gall and leafy gall disease, respectively, resulting in undesirable growth abnormalities. When present in nurseries, plants infected by either bacterium are destroyed, resulting in substantial losses for growers, especially those producing plants valued for their ornamental attributes. There are many unanswered questions regarding pathogen transmission on tools used to take cuttings for propagation and whether products used for bacterial disease control are effective. We investigated the ability to transmit pathogenic A. tumefaciens and R. fascians on secateurs and the efficacy of registered control products against both bacteria in vitro and in vivo. Experimental plants used were Rosa × hybrida, Leucanthemum × superbum, and Chrysanthemum × grandiflorum for A. tumefaciens and Petunia × hybrida and Oenothera 'Siskiyou' with R. fascians. In separate experiments, we found secateurs could convey both bacteria in numbers sufficient to initiate disease in a host-dependent manner and that bacteria could be recovered from secateurs after a single cut through an infected stem. In in vivo assays, none of six products tested against A. tumefaciens prevented crown gall disease, although several products appeared promising in in vitro trials. Likewise, four compounds trialed against R. fascians failed to prevent disease. Sanitation and clean planting material remain the primary means of disease management.
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Affiliation(s)
- Michael I Gordon
- Department of Plant Pathology, Oregon State University, Corvallis, OR 97331
| | - William J Thomas
- Department of Plant Pathology, Oregon State University, Corvallis, OR 97331
| | - Melodie L Putnam
- Department of Plant Pathology, Oregon State University, Corvallis, OR 97331
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Iles LC, Fulladolsa AC, Smart A, Bonkowski J, Creswell T, Harmon CL, Hammerschmidt R, Hirch RR, Rodriguez Salamanca L. Everything Is Faster: How Do Land-Grant University-Based Plant Diagnostic Laboratories Keep Up with a Rapidly Changing World? ANNUAL REVIEW OF PHYTOPATHOLOGY 2021; 59:333-349. [PMID: 34432509 DOI: 10.1146/annurev-phyto-020620-102557] [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
Plant diagnostic laboratories (PDLs) are at the heart of land-grant universities (LGUs) and their extension mission to connect citizens with research-based information. Although research and technological advances have led to many modern methods and technologies in plant pathology diagnostics, the pace of adopting those methods into services at PDLs has many complexities we aim to explore in this review. We seek to identify current challenges in plant disease diagnostics, as well as diagnosticians' and administrators'perceptions of PDLs' many roles. Surveys of diagnosticians and administrators were conducted to understand the current climate on these topics. We hope this article reaches researchers developing diagnostic methods with modern and new technologies to foster a better understanding of PDL diagnosticians' perspective on method implementation. Ultimately, increasing researchers' awareness of the factors influencing method adoption by PDLs encourages support, collaboration, and partnerships to advance plant diagnostics.
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Affiliation(s)
- Laura C Iles
- Department of Plant Pathology, Iowa State University, Ames, Iowa 50011;
| | - Ana C Fulladolsa
- Department of Agricultural Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Alicyn Smart
- Cooperative Extension, University of Maine, Orono, Maine 04473
| | - John Bonkowski
- Plant and Pest Diagnostic Laboratory, Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
| | - Tom Creswell
- Plant and Pest Diagnostic Laboratory, Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
| | - Carrie L Harmon
- Department of Plant Pathology, University of Florida, Gainesville, Florida 32611
| | - Ray Hammerschmidt
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824
| | - R Roz Hirch
- Department of English, Iowa State University, Ames, Iowa 50011
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Detection of Rhodococcus fascians, the Causative Agent of Lily Fasciation in South Korea. Pathogens 2021; 10:pathogens10020241. [PMID: 33672562 PMCID: PMC7924060 DOI: 10.3390/pathogens10020241] [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: 01/18/2021] [Revised: 02/10/2021] [Accepted: 02/18/2021] [Indexed: 12/03/2022] Open
Abstract
Rhodococcus fascians is an important pathogen that infects various herbaceous perennials and reduces their economic value. In this study, we examined R. fascians isolates carrying a virulence gene from symptomatic lily plants grown in South Korea. Phylogenetic analysis using the nucleotide sequences of 16S rRNA, vicA, and fasD led to the classification of the isolates into four different strains of R. fascians. Inoculation of Nicotiana benthamiana with these isolates slowed root growth and resulted in symptoms of leafy gall. These findings elucidate the diversification of domestic pathogenic R. fascians and may lead to an accurate causal diagnosis to help reduce economic losses in the bulb market.
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Yeon-Jeong L, Kong HG, Lee YH, Kim HR, Park DH. First Report of Rhodococcus fascians Causing Fasciation of Lilies ( Lilium longiflorum Thunb.) in South Korea. PLANT DISEASE 2020; 105:1190. [PMID: 33349008 DOI: 10.1094/pdis-10-20-2288-pdn] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Rhodococcus fascians is a bacterium that causes growth abnormalities such as leafy galls, fasciation, and shoot proliferation in many plants, including ornamental plants. In February 2020, the Animal and Plant Quarantine Agency of South Korea detected 492,000 contaminated lily bulbs using an in-house PCR test based on the R. fascians fasD gene, and subsequently 1.3 million imported bulbs were destroyed. Because no pathogen isolation was associated with this diagnosis, there has been great cultivator demanded for bacterial isolation evidence of lily bulb infection with pathogenic R. fascians. To isolate the causal bacterium of the PCR tests, we sampled leaf, stem, and bulb tissues from 130 lilies with growth abnormality symptoms, collected from 24 South Korean mass production lily farms from June to August 2020. Supernatants of the homogenized samples were spread on mD2 medium (Kado and Heskett 1970) and incubated at 28°C for 10 days. Yellow to orange colonies were isolated into pure culture on mD2. Total DNA was extracted from cultures grown in yeast extract broth (YEB) at 28°C for 24 hours with Wizard DNA prep kit (Promega, Madison, WI, USA). PCR was performed to test for pathogenicity genes fas (A,D, and R) and att (A and R) (Putnam and Miller 2007). Colonies that produced at least one amplicon from these pathogenicity genes were analyzed by partial 16s rRNA gene sequencing to determine the corresponding species. Three strains that were isolated from the bulbs of fasciated lilies from Wanju (35°56´22.1˝N; 127°08´52.0˝E), Gwacheon (37°26´51.6˝N; 127°00´11.8˝E), and Yeongwol (37°18´45.8˝N; 128°11´05.6˝E), or W1, G3, and Y5 strains, yielded PCR products of the expected size for fas and att genes with the primer sets published in Serdani et al. (2013) and developed in this study (attAF: 5'-CCCGGCTACACGCATTCGC-3', attAR: 5'-CGAACGCGGTGTGCAGGT-3' and attRF: 5'-AGTGTCCCGTCGGCGAG-3', attRR: 5'-CGCGGCAGATCGAAGTCCT-3'). Sequences of the three strains were deposited in Genbank for fasA (accession MW122940-942), fasD (G3:MW122935 and 936), and fasR (MW122937-939); all shared 98.3 - 100% nucleotide identity to corresponding sequences from phytopathogenic R. fascians A25f (CP049745.1 Protein_ID fasA:QII09280.1, fasD:QII09282.1, and fasR:QII09277.1). The attA and attR products were only present in G3 (attA: MW122943 and attR: MW122944) and resulted in 100% identity to those of A25f (CP049745.1 Protein_ID attA:QII09269.1, attR:QII09267.1). Partial 16s rRNA gene sequences were obtained (MW064131-133) and clustered with phytopathogenic R. fascians strains D188, A21d2, and A25f. Thus we concluded that strains (W1, G3, and Y5) corresponded to R. fascians. To test the pathogenicity of these three strains, 10 seeds of garden peas for each strain were inoculated at 108 CFU/ml according to Nikolaeva et al. (2009), and the length of the main stem of each seedling was calculated 22 days post-inoculation. Seedlings inoculated with G3 and Y5 resulted in a stunted phenotype with up to 40% height reduction (p ≤ 0.001) compared to non-inoculated seedlings. As for the seedlings inoculated with W1, they exhibited as much as 15% height reduction (p ≤ 0.001). Colonies were recovered from the inoculated seedlings, identity was confirmed through colony PCR for fas and att genes. To our knowledge, this is the first report of phytopathogenic R. fascians in lilies cultivated in South Korea.
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Affiliation(s)
- Lim Yeon-Jeong
- Kangwon National University, Department of Applied Biology, College of Agriculture and Life Sciences, Chuncheon, Korea (the Republic of);
| | - Hyun Gi Kong
- Rural Development Administration, 54670, National Institute of Agricultural Sciences, Wanju-gun, 54875, South Korea, Jeonju, Korea (the Republic of), 54875;
| | - Yong Hwan Lee
- National Institute of Agricultural Sciences, 230986, Crop Protection Division, 166, Nongsaengmyeong-ro, Iseo-myeon, Wanju, Jeollabuk-do, Korea (the Republic of), 55365;
| | - Hyun Ran Kim
- National Institute of Horticultural&herbal science, fruit science, 203, cheoncheon-ro jangan-gu, Suwon, gyeonggi-do, Korea (the Republic of), 440-706;
| | - Duck Hwan Park
- Kangwon National University, Department of Applied Biology, College of Agriculture and Life Sciences, Kangwon daehak road 1, Chuncheon, Korea (the Republic of), 24341;
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Carvalhais LC, Henderson J, Rincon-Florez VA, O’Dwyer C, Czislowski E, Aitken EAB, Drenth A. Molecular Diagnostics of Banana Fusarium Wilt Targeting Secreted-in-Xylem Genes. FRONTIERS IN PLANT SCIENCE 2019; 10:547. [PMID: 31214206 PMCID: PMC6554419 DOI: 10.3389/fpls.2019.00547] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/10/2019] [Indexed: 06/01/2023]
Abstract
Fusarium wilt is currently spreading in banana growing regions around the world leading to substantial losses. The disease is caused by the fungus Fusarium oxysporum f. sp. cubense (Foc), which is further classified into distinct races according to the banana varieties that they infect. Cavendish banana is resistant to Foc race 1, to which the popular Gros Michel subgroup succumbed last century. Cavendish effectively saved the banana industry, and became the most cultivated commercial subgroup worldwide. However, Foc tropical race 4 (TR4) subsequently emerged in Southeast Asia, causing significant yield losses due to its high level of aggressiveness to cultivars of Cavendish, and other commonly grown cultivars. Preventing further spread is crucially important in the absence of effective control methods or resistant market-acceptable banana cultivars. Implementation of quarantine and containment measures depends on early detection of the pathogen through reliable diagnostics. In this study, we tested the hypothesis that secreted in xylem (SIX) genes, which currently comprise the only known family of effectors in F. oxysporum, contain polymorphisms to allow the design of molecular diagnostic assays that distinguish races and relevant VCGs of Foc. We present specific and reproducible diagnostic assays based on conventional PCR targeting SIX genes, using as templates DNA extracted from pure Foc cultures. Sets of primers specifically amplify regions of: SIX6 in Foc race 1, SIX1 gene in TR4, SIX8 in subtropical race 4, SIX9/SIX10 in Foc VCG 0121, and SIX13 in Foc VCG 0122. These assays include simplex and duplex PCRs, with additional restriction digestion steps applied to amplification products of genes SIX1 and SIX13. Assay validations were conducted to a high international standard including the use of 250 Fusarium spp. isolates representing 16 distinct Fusarium species, 59 isolates of F. oxysporum, and 21 different vegetative compatibility groups (VCGs). Tested parameters included inter and intraspecific analytical specificity, sensitivity, robustness, repeatability, and reproducibility. The resulting suite of assays is able to reliably and accurately detect R1, STR4, and TR4 as well as two VCGs (0121 and 0122) causing Fusarium wilt in bananas.
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Affiliation(s)
- Lilia C. Carvalhais
- Queensland Alliance for Agriculture and Food Innovation, Centre for Horticultural Science, Ecosciences Precinct, The University of Queensland, Brisbane, QLD, Australia
| | - Juliane Henderson
- Queensland Alliance for Agriculture and Food Innovation, Centre for Horticultural Science, Ecosciences Precinct, The University of Queensland, Brisbane, QLD, Australia
| | - Vivian A. Rincon-Florez
- Queensland Alliance for Agriculture and Food Innovation, Centre for Horticultural Science, Ecosciences Precinct, The University of Queensland, Brisbane, QLD, Australia
| | - Cecilia O’Dwyer
- Queensland Alliance for Agriculture and Food Innovation, Centre for Horticultural Science, Ecosciences Precinct, The University of Queensland, Brisbane, QLD, Australia
| | - Elizabeth Czislowski
- School of Agriculture and Food Sciences, The University of Queenslandxy3Saint Lucia, QLD, Australia
| | - Elizabeth A. B. Aitken
- School of Agriculture and Food Sciences, The University of Queenslandxy3Saint Lucia, QLD, Australia
| | - André Drenth
- Queensland Alliance for Agriculture and Food Innovation, Centre for Horticultural Science, Ecosciences Precinct, The University of Queensland, Brisbane, QLD, Australia
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Wang X, Gao Q, Wang W, Wang X, Lei C, Zhu F. The gut bacteria across life stages in the synanthropic fly Chrysomya megacephala. BMC Microbiol 2018; 18:131. [PMID: 30305025 PMCID: PMC6180576 DOI: 10.1186/s12866-018-1272-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 09/27/2018] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Gut bacteria are closely associated with host. Chrysomya megacephala, as a vector and resource insect, can transmit various pathogenic bacteria and consume manure to produce biofertilizer and larva biomass. However, the gut bacteria composition and abundance of C. megacephala remain unclear. RESULTS Illumina MiSeq platform was used to compare composition of gut bacterial community in eggs, 1-day-old larvae, 5-day-old larvae, pupae, adult females and males by sequencing with variation in V4 region of 16S ribosomal DNA gene. In total, 928 operational taxonomic units (OTUs) were obtained. These OTUs were annotated into 19 phyla, 42 classes, 77 orders, 153 families and 289 genera. More than 0.5% abundance of 32 OTU core genera were found across all life stages. At class level, Alphaproteobacteria, Bacilli, Bacteroidia, Betaproteobacteria, Flavobacteriia and Gammaproteobacteria were the most abundant in C. megacephala. Eight species were identified to have significantly different abundance between 1-d-larvae and 5-day-larvae and took 28.95% of shared species between these two groups. Sex-specific bacterial species were identified that Faecalibacterium prausnitzii was merely present in females, while Rhodococcus fascians was merely present in males. CONCLUSION Gut bacteria of C. megacephala varied across life stages. The composition and community structure of the bacterial community differed from young larvae to mature larvae, while that were similar in adult females and males. These data will provide an overall view of bacterial community across life stages in C. megacephala with attention on manure associated and pathogenic bacteria.
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Affiliation(s)
- Xiaoyun Wang
- Hubei International Scientific and Technological Cooperation Base of Waste Conversion by Insects, Huazhong Agricultural University, Wuhan, 430070 China
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan, 430070 China
| | - Qiao Gao
- Hubei International Scientific and Technological Cooperation Base of Waste Conversion by Insects, Huazhong Agricultural University, Wuhan, 430070 China
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan, 430070 China
| | - Wanqiang Wang
- Hubei International Scientific and Technological Cooperation Base of Waste Conversion by Insects, Huazhong Agricultural University, Wuhan, 430070 China
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan, 430070 China
| | - Xiaoping Wang
- Hubei International Scientific and Technological Cooperation Base of Waste Conversion by Insects, Huazhong Agricultural University, Wuhan, 430070 China
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan, 430070 China
| | - Chaoliang Lei
- Hubei International Scientific and Technological Cooperation Base of Waste Conversion by Insects, Huazhong Agricultural University, Wuhan, 430070 China
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan, 430070 China
| | - Fen Zhu
- Hubei International Scientific and Technological Cooperation Base of Waste Conversion by Insects, Huazhong Agricultural University, Wuhan, 430070 China
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan, 430070 China
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Savory EA, Fuller SL, Weisberg AJ, Thomas WJ, Gordon MI, Stevens DM, Creason AL, Belcher MS, Serdani M, Wiseman MS, Grünwald NJ, Putnam ML, Chang JH. Evolutionary transitions between beneficial and phytopathogenic Rhodococcus challenge disease management. eLife 2017; 6:30925. [PMID: 29231813 PMCID: PMC5726852 DOI: 10.7554/elife.30925] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 11/03/2017] [Indexed: 02/02/2023] Open
Abstract
Understanding how bacteria affect plant health is crucial for developing sustainable crop production systems. We coupled ecological sampling and genome sequencing to characterize the population genetic history of Rhodococcus and the distribution patterns of virulence plasmids in isolates from nurseries. Analysis of chromosome sequences shows that plants host multiple lineages of Rhodococcus, and suggested that these bacteria are transmitted due to independent introductions, reservoir populations, and point source outbreaks. We demonstrate that isolates lacking virulence genes promote beneficial plant growth, and that the acquisition of a virulence plasmid is sufficient to transition beneficial symbionts to phytopathogens. This evolutionary transition, along with the distribution patterns of plasmids, reveals the impact of horizontal gene transfer in rapidly generating new pathogenic lineages and provides an alternative explanation for pathogen transmission patterns. Results also uncovered a misdiagnosed epidemic that implicated beneficial Rhodococcus bacteria as pathogens of pistachio. The misdiagnosis perpetuated the unnecessary removal of trees and exacerbated economic losses. All organisms live in a world teeming with bacteria. Some bacteria are beneficial and, for example, provide their hosts with nutrients. Others cause harm, for example, by stealing nutrients and causing disease. Many bacteria can also gain DNA from other bacteria, and the genes encoded within the new DNA can help them to live with other organisms. This can start the bacteria on an evolutionary path to becoming beneficial or harmful. Rhodococcus are bacteria that live in association with many species of plants, including trees. Most are harmless but some cause disease. Plants infected with harmful Rhodococcus can show deformed growth, which causes major losses to the nursery industry. Savory, Fuller, Weisberg et al. set out to understand how disease-causing Rhodococcus are introduced into nurseries, if they are transferred between nurseries, whether they persist in nurseries, and how to limit their spread. It turns out that harmless Rhodococcus are beneficial to plants. However, if these harmless bacteria gain a certain DNA molecule – called a virulence plasmid – they can convert into harmful bacteria. Further analysis showed that some nurseries repeatedly acquired the harmful bacteria. The pattern of affected nurseries suggested that some might have purchased diseased plants from a common provider. In other cases, the sources remained a mystery. Savory et al. also report that, contrary to previous findings, there is no evidence to support the diagnosis that Rhodococcus without a virulence plasmid are responsible for an unusual growth problem that has plagued the pistachio industry. In recent years, this incorrect diagnosis led to trees being unnecessarily destroyed, worsening the economic losses. These findings suggest that genes moving between bacteria can dramatically change how those bacteria interact with the organisms in which they live. It needs to be shown whether this is an exceptional process, unique to only certain groups of bacteria, or if it is more widespread in nature. These findings could inform future disease management strategies to better protect agricultural systems.
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Affiliation(s)
- Elizabeth A Savory
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - Skylar L Fuller
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States.,Molecular and Cellular Biology Program, Oregon State University, Corvallis, United States
| | - Alexandra J Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - William J Thomas
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - Michael I Gordon
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - Danielle M Stevens
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - Allison L Creason
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States.,Molecular and Cellular Biology Program, Oregon State University, Corvallis, United States
| | - Michael S Belcher
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - Maryna Serdani
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - Michele S Wiseman
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - Niklaus J Grünwald
- Horticultural Crops Research Laboratory, United States Department of Agriculture and Agricultural Research Service, Corvallis, United States
| | - Melodie L Putnam
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, United States.,Molecular and Cellular Biology Program, Oregon State University, Corvallis, United States.,Center for Genome Research, Oregon State University, Corvallis, United States
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Stamler RA, Kilcrease J, Kallsen C, Fichtner EJ, Cooke P, Heerema RJ, Randall JJ. First Report of Rhodococcus Isolates Causing Pistachio Bushy Top Syndrome on 'UCB-1' Rootstock in California and Arizona. PLANT DISEASE 2015; 99:1468-1476. [PMID: 30695969 DOI: 10.1094/pdis-12-14-1340-re] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
'UCB-1' (Pistacia atlantica × Pistacia integerrima) rootstock is a hybrid cultivar widely used by the U.S. pistachio industry. In the last three years, a large number of micropropagated UCB-1 pistachio rootstocks planted in California and Arizona orchards exhibited shortened internodes, stunted growth, swollen lateral buds, bushy/bunchy growth, stem galls with multiple buds, and twisted roots with minimal lateral branching. Field T-budding success in affected orchards was reduced to approximately 30% with unusual bark cracking often observed around the bud-union. The percentage of abnormal rootstocks within affected orchards varied from 10 to 90%. We have termed the cumulative symptoms "pistachio bushy top syndrome" (PBTS) to describe these affected trees. Two isolates, both containing virulence factors from the phytopathogen Rhodococcus fascians, were identified on symptomatic trees in field and nursery samples. Micropropagated UCB-1 trees inoculated with the Rhodococcus isolates exhibited stunted growth, shortened internode length, swollen lateral buds, sylleptic branching, and differences in root morphology, compared with control UCB-1 trees. To our knowledge, this is the first report of Rhodococcus isolates, related to Rhodococcus fascians, causing disease on a commercial tree crop and the results presented indicate that this organism is responsible at least in part for PBTS in California and Arizona.
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Affiliation(s)
- Rio A Stamler
- Department of Entomology, Plant Pathology, and Weed Science, New Mexico State University, Las Cruces, NM 88003
| | - James Kilcrease
- Department of Entomology, Plant Pathology, and Weed Science, New Mexico State University, Las Cruces, NM 88003
| | - Craig Kallsen
- University of California, Cooperative Extension, Bakersfield, CA 93307
| | | | - Peter Cooke
- Core University Resource Laboratory, New Mexico State University, Las Cruces, NM 88003
| | | | - Jennifer J Randall
- Department of Entomology, Plant Pathology, and Weed Science, New Mexico State University, Las Cruces, NM 88003
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Tarkowski P, Vereecke D. Threats and opportunities of plant pathogenic bacteria. Biotechnol Adv 2013; 32:215-29. [PMID: 24216222 DOI: 10.1016/j.biotechadv.2013.11.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 10/22/2013] [Accepted: 11/03/2013] [Indexed: 02/08/2023]
Abstract
Plant pathogenic bacteria can have devastating effects on plant productivity and yield. Nevertheless, because these often soil-dwelling bacteria have evolved to interact with eukaryotes, they generally exhibit a strong adaptivity, a versatile metabolism, and ingenious mechanisms tailored to modify the development of their hosts. Consequently, besides being a threat for agricultural practices, phytopathogens may also represent opportunities for plant production or be useful for specific biotechnological applications. Here, we illustrate this idea by reviewing the pathogenic strategies and the (potential) uses of five very different (hemi)biotrophic plant pathogenic bacteria: Agrobacterium tumefaciens, A. rhizogenes, Rhodococcus fascians, scab-inducing Streptomyces spp., and Pseudomonas syringae.
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Affiliation(s)
- Petr Tarkowski
- Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-78371 Olomouc, Czech Republic.
| | - Danny Vereecke
- Department of Applied Biosciences, Faculty of Bioscience Engineering, Ghent University, Valentin Vaerwyckweg 1, BE-9000 Ghent, Belgium.
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