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Mandal MK, Koike ST, Tsuchida C, Stanghellini H, Guerrero J, Sandoya GV, Klosterman SJ, Simko I, Subbarao KV. Distribution of Three Verticillium dahliae Races in Coastal California and Evaluation of Resistance in Lettuce. PLANT DISEASE 2024:PDIS01240193RE. [PMID: 38506911 DOI: 10.1094/pdis-01-24-0193-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
Verticillium wilt, caused by Verticillium dahliae, is one of the most devastating soilborne diseases of lettuce (Lactuca sativa L.). There are three races of V. dahliae, and each race has been characterized by markers representing race-specific effectors. Race 1 is differentiated by the presence of the functional secretory Ave1 effector. Similarly, races 2 and 3 are differentiated by effectors VdR2e and VdR3e, respectively. Although the presence of race 1 in coastal California was well established, the presence of effector-based races 2 and 3 was uncertain. This study therefore focused on characterizing 727 isolates collected from 142 ranches of symptomatic lettuce and other crops from coastal California. Based on this evaluation, 523 isolates were designated as race 1, 20 isolates as race 2, 23 isolates as race 3, and 17 as race undefined. Isolates representing other Verticillium species totaled 110, and 34 were non-Verticillium fungal species. Because the use of resistant cultivars is a key strategy to manage this disease, we evaluated 48 lettuce germplasm lines and 1 endive (Cichorium endivia L.) line, comprising commercial cultivars and breeding lines, including the race 1-resistant heirloom cultivar La Brillante and the susceptible cultivar Salinas as controls. Resistance against races 1, 2, and 3 along with VdLs17, a virulent isolate of V. dahliae from lettuce that is currently not assigned to a race, was evaluated in replicated greenhouse experiments. Two crisphead lettuce lines, HL28 and HL29, exhibited resistance against race 1 and a partial resistance against race 2, whereas all other lines were highly susceptible to races 1 and 2 and VdLs17. The majority of lines exhibited higher resistance to race 3 relative to the other two races. This study documents the current distribution of the different races in coastal California. In addition, the sources of resistance currently being developed should be effective or partially effective against these races for targeted deployment as soon as they are available.
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Affiliation(s)
- Mihir K Mandal
- Department of Plant Pathology, University of California, Davis, c/o Sam Farr United States Crop Improvement and Protection Research Center, Salinas, CA 93905
| | | | | | | | | | - Germán V Sandoya
- Horticultural Sciences Department, Everglades Research & Education Center, University of Florida, Belle Glade, FL 33430
| | - Steven J Klosterman
- Sam Farr United States Crop Improvement and Protection Research Center, U.S. Department of Agriculture, Agricultural Research Service, Salinas, CA 93905
| | - Ivan Simko
- Sam Farr United States Crop Improvement and Protection Research Center, U.S. Department of Agriculture, Agricultural Research Service, Salinas, CA 93905
| | - Krishna V Subbarao
- Department of Plant Pathology, University of California, Davis, c/o Sam Farr United States Crop Improvement and Protection Research Center, Salinas, CA 93905
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Zhang YD, Ji XB, Zong J, Dai XF, Klosterman SJ, Subbarao KV, Zhang DD, Chen JY. Functional analysis of the mating type genes in Verticillium dahliae. BMC Biol 2024; 22:108. [PMID: 38714997 PMCID: PMC11077750 DOI: 10.1186/s12915-024-01900-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 04/22/2024] [Indexed: 05/12/2024] Open
Abstract
BACKGROUND Populations of the plant pathogenic fungus Verticillium dahliae display a complex and rich genetic diversity, yet the existence of sexual reproduction in the fungus remains contested. As pivotal genes, MAT genes play a crucial role in regulating cell differentiation, morphological development, and mating of compatible cells. However, the functions of the two mating type genes in V. dahliae, VdMAT1-1-1, and VdMAT1-2-1, remain poorly understood. RESULTS In this study, we confirmed that the MAT loci in V. dahliae are highly conserved, including both VdMAT1-1-1 and VdMAT1-2-1 which share high collinearity. The conserved core transcription factor encoded by the two MAT loci may facilitate the regulation of pheromone precursor and pheromone receptor genes by directly binding to their promoter regions. Additionally, peptide activity assays demonstrated that the signal peptide of the pheromone VdPpg1 possessed secretory activity, while VdPpg2, lacked a predicted signal peptide. Chemotactic growth assays revealed that V. dahliae senses and grows towards the pheromones FO-a and FO-α of Fusarium oxysporum, as well as towards VdPpg2 of V. dahliae, but not in response to VdPpg1. The findings herein also revealed that VdMAT1-1-1 and VdMAT1-2-1 regulate vegetative growth, carbon source utilization, and resistance to stressors in V. dahliae, while negatively regulating virulence. CONCLUSIONS These findings underscore the potential roles of VdMAT1-1-1 and VdMAT1-2-1 in sexual reproduction and confirm their involvement in various asexual processes of V. dahliae, offering novel insights into the functions of mating type genes in this species.
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Affiliation(s)
- Ya-Duo Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Xiao-Bin Ji
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Juan Zong
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Xiao-Feng Dai
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Steven J Klosterman
- United States Department of Agriculture, Agricultural Research Service, Salinas, CA, USA
| | - Krishna V Subbarao
- Department of Plant Pathology, University of California, Davis, c/o United States Agricultural Research Station, Salinas, CA, USA.
| | - Dan-Dan Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
- Western Agricultural Research Center, Chinese Academy of Agricultural Sciences, Changji, 831100, China.
| | - Jie-Yin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
- Western Agricultural Research Center, Chinese Academy of Agricultural Sciences, Changji, 831100, China.
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Thierry M, Charriat F, Milazzo J, Adreit H, Ravel S, Cros-Arteil S, borron S, Sella V, Kroj T, Ioos R, Fournier E, Tharreau D, Gladieux P. Maintenance of divergent lineages of the Rice Blast Fungus Pyricularia oryzae through niche separation, loss of sex and post-mating genetic incompatibilities. PLoS Pathog 2022; 18:e1010687. [PMID: 35877779 PMCID: PMC9352207 DOI: 10.1371/journal.ppat.1010687] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 08/04/2022] [Accepted: 06/17/2022] [Indexed: 11/18/2022] Open
Abstract
Many species of fungal plant pathogens coexist as multiple lineages on the same host, but the factors underlying the origin and maintenance of population structure remain largely unknown. The rice blast fungus Pyricularia oryzae is a widespread model plant pathogen displaying population subdivision. However, most studies of natural variation in P. oryzae have been limited in genomic or geographic resolution, and host adaptation is the only factor that has been investigated extensively as a contributor to population subdivision. In an effort to complement previous studies, we analyzed genetic and phenotypic diversity in isolates of the rice blast fungus covering a broad geographical range. Using single-nucleotide polymorphism genotyping data for 886 isolates sampled from 152 sites in 51 countries, we showed that population subdivision of P. oryzae in one recombining and three clonal lineages with broad distributions persisted with deeper sampling. We also extended previous findings by showing further population subdivision of the recombining lineage into one international and three Asian clusters, and by providing evidence that the three clonal lineages of P. oryzae were found in areas with different prevailing environmental conditions, indicating niche separation. Pathogenicity tests and bioinformatic analyses using an extended set of isolates and rice varieties indicated that partial specialization to rice subgroups contributed to niche separation between lineages, and differences in repertoires of putative virulence effectors were consistent with differences in host range. Experimental crosses revealed that female sterility and early post-mating genetic incompatibilities acted as strong additional barriers to gene flow between clonal lineages. Our results demonstrate that the spread of a fungal pathogen across heterogeneous habitats and divergent populations of a crop species can lead to niche separation and reproductive isolation between distinct, widely distributed, lineages.
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Affiliation(s)
- Maud Thierry
- PHIM Plant Health Institute, Univ Montpellier, INRAE, CIRAD, Institut Agro, IRD, Montpellier, France
- CIRAD, UMR PHIM, Montpellier, France
- ANSES Plant Health Laboratory, Mycology Unit, Malzéville, France
| | - Florian Charriat
- PHIM Plant Health Institute, Univ Montpellier, INRAE, CIRAD, Institut Agro, IRD, Montpellier, France
| | - Joëlle Milazzo
- PHIM Plant Health Institute, Univ Montpellier, INRAE, CIRAD, Institut Agro, IRD, Montpellier, France
- CIRAD, UMR PHIM, Montpellier, France
| | - Henri Adreit
- PHIM Plant Health Institute, Univ Montpellier, INRAE, CIRAD, Institut Agro, IRD, Montpellier, France
- CIRAD, UMR PHIM, Montpellier, France
| | - Sébastien Ravel
- PHIM Plant Health Institute, Univ Montpellier, INRAE, CIRAD, Institut Agro, IRD, Montpellier, France
- CIRAD, UMR PHIM, Montpellier, France
| | - Sandrine Cros-Arteil
- PHIM Plant Health Institute, Univ Montpellier, INRAE, CIRAD, Institut Agro, IRD, Montpellier, France
| | - Sonia borron
- PHIM Plant Health Institute, Univ Montpellier, INRAE, CIRAD, Institut Agro, IRD, Montpellier, France
| | - Violaine Sella
- ANSES Plant Health Laboratory, Mycology Unit, Malzéville, France
| | - Thomas Kroj
- PHIM Plant Health Institute, Univ Montpellier, INRAE, CIRAD, Institut Agro, IRD, Montpellier, France
| | - Renaud Ioos
- ANSES Plant Health Laboratory, Mycology Unit, Malzéville, France
| | - Elisabeth Fournier
- PHIM Plant Health Institute, Univ Montpellier, INRAE, CIRAD, Institut Agro, IRD, Montpellier, France
| | - Didier Tharreau
- PHIM Plant Health Institute, Univ Montpellier, INRAE, CIRAD, Institut Agro, IRD, Montpellier, France
- CIRAD, UMR PHIM, Montpellier, France
- * E-mail: (DT); (PG)
| | - Pierre Gladieux
- PHIM Plant Health Institute, Univ Montpellier, INRAE, CIRAD, Institut Agro, IRD, Montpellier, France
- * E-mail: (DT); (PG)
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4
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Zhang YD, Zhang YY, Chen JY, Huang JQ, Zhang J, Liu L, Wang D, Zhao J, Song J, Li R, Yang L, Kong ZQ, Klosterman SJ, Subbarao KV, Dai XF, Zhang DD. Genome Sequence Data of MAT1-1 and MAT1-2 Idiomorphs from Verticillium dahliae. PHYTOPATHOLOGY 2021; 111:1686-1691. [PMID: 33673752 DOI: 10.1094/phyto-01-21-0012-a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Though Verticillium dahliae is an asexually reproducing fungus, it is considered heterothallic owing to the presence of only one of the two mating-type idiomorphs (MAT1-1 or MAT1-2) in individual isolates. But sexual reproduction has never been observed either in nature or in the laboratory. All of the genomic information in the literature thus far has therefore come from studies on isolates carrying only the MAT1-2 idiomorph. Herein, we sequenced and compared high-quality reference genomes of MAT1-1 strain S011 and MAT1-2 strain S023 obtained from the same sunflower field. The two genomic sequences displayed high synteny, and encoded similar number genes, a similarity especially notable among pathogenicity-related genes. Homolog analysis between these two genomes revealed that 80% of encoded genes are highly conserved (95% identity and coverage), but only 20% of the single copy genes were identical. These novel genome resources will support the analysis of the structure and function of the two idiomorphs and provide valuable tools to elucidate the evolution and potential mechanisms of sexual reproduction in V. dahliae.
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Affiliation(s)
- Ya-Duo Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Yuan-Yuan Zhang
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot, 010018, China
| | - Jie-Yin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | | | - Jian Zhang
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot, 010018, China
| | - Lin Liu
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot, 010018, China
| | - Dan Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Jun Zhao
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot, 010018, China
| | - Jian Song
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Ran Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Lin Yang
- BGI-Genomics, BGI-Shenzhen, Shenzhen, 518083, China
| | - Zhi-Qiang Kong
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Steven J Klosterman
- U.S. Department of Agriculture, Agricultural Research Service, Crop Improvement and Protection Research Unit, Salinas, CA, U.S.A
| | - Krishna V Subbarao
- Department of Plant Pathology, University of California, Davis, c/o U.S. Agricultural Research Station, Salinas, CA, U.S.A
| | - Xiao-Feng Dai
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Dan-Dan Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
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5
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Chen JY, Klosterman SJ, Hu XP, Dai XF, Subbarao KV. Key Insights and Research Prospects at the Dawn of the Population Genomics Era for Verticillium dahliae. ANNUAL REVIEW OF PHYTOPATHOLOGY 2021; 59:31-51. [PMID: 33891830 DOI: 10.1146/annurev-phyto-020620-121925] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The genomics era has ushered in exciting possibilities to examine the genetic bases that undergird the characteristic features of Verticillium dahliae and other plant pathogens. In this review, we provide historical perspectives on some of the salient biological characteristics of V. dahliae, including its morphology, microsclerotia formation, host range, disease symptoms, vascular niche, reproduction, and population structure. The kaleidoscopic population structure of this pathogen is summarized, including different races of the pathogen, defoliating and nondefoliating phenotypes, vegetative compatibility groupings, and clonal populations. Where possible, we place the characteristic differences in the context of comparative and functional genomics analyses that have offered insights into population divergence within V. dahliae and the related species.Current challenges are highlighted along with some suggested future population genomics studies that will contribute to advancing our understanding of the population divergence in V. dahliae.
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Affiliation(s)
- Jie-Yin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; ,
| | - Steven J Klosterman
- Agricultural Research Service, United States Department of Agriculture, Salinas, California 93905, USA;
| | - Xiao-Ping Hu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling 712100, China;
| | - Xiao-Feng Dai
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; ,
| | - Krishna V Subbarao
- Department of Plant Pathology, University of California, Davis, California 93905, USA;
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6
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Li P, Liu M, Li G, Liu K, Liu T, Wu M, Saleem M, Li Z. Phosphorus availability increases pathobiome abundance and invasion of rhizosphere microbial networks by Ralstonia. Environ Microbiol 2021; 23:5992-6003. [PMID: 34347357 DOI: 10.1111/1462-2920.15696] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 07/26/2021] [Accepted: 07/28/2021] [Indexed: 12/16/2022]
Abstract
Soil disease-suppressiveness depends on complex interactions among pathogens, native microbiota, and physicochemical properties, while these interactions remain understudied. Comparing field and microcosm experiments, we investigated the significance of these interactions in disease emergence or suppression using structural equation modelling (SEM) and receiver operating characteristic curve (ROC) analyses. We observed significant differences in the relative abundance of pathogenic and beneficial microbes, alpha and beta diversity indices between disease-conducive and -suppressive rhizosphere soils. The pathogenic (Ralstonia) and beneficial (Bacillus) taxa dominated disease-conducive and -suppressive rhizosphere soils, respectively. Moreover, the co-occurrences of Ralstonia with native microorganisms were positive and negative in the disease-conducive and -suppressive soils, respectively. These results suggest the supportive (Rudaea) and suppressive (Enterobacter, Bacillus) role of indigenous microbes in the invasion of soil and plant systems by Ralstonia. The SEM and ROC analysis predicted that Ralstonia invaded rhizospheric microbial networks and caused peanut wilt under high than low soil phosphorus conditions. Our results suggest the importance of soil phosphorus availability in altering the microbial interactions, thus leading to soil invasion by Ralstonia. Thus, we conclude by saying that feeding soil with high amounts of available phosphorus could deplete plant-beneficial microbes and increase the pathobiome abundance that may compromise plant health.
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Affiliation(s)
- Pengfa Li
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ming Liu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guilong Li
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Kai Liu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Tianshun Liu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Meng Wu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Muhammad Saleem
- Department of Biological Sciences, Alabama State University, Montgomery, AL, 36104, USA
| | - Zhongpei Li
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
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7
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Gur L, Reuveni M, Cohen Y, Cadle-Davidson L, Kisselstein B, Ovadia S, Frenkel O. Population structure of Erysiphe necator on domesticated and wild vines in the Middle East raises questions on the origin of the grapevine powdery mildew pathogen. Environ Microbiol 2021; 23:6019-6037. [PMID: 33459475 DOI: 10.1111/1462-2920.15401] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 11/28/2022]
Abstract
Plant pathogens usually originate and diversify in geographical regions where hosts and pathogens co-evolve. Erysiphe necator, the causal agent of grape powdery mildew, is a destructive pathogen of grapevines worldwide. Although Eastern US is considered the centre of origin and diversity of E. necator, previous reports on resistant native wild and domesticated Asian grapevines suggest Asia as another possible origin of the pathogen. By using multi-locus sequencing, microsatellites and a novel application of amplicon sequencing (AmpSeq), we show that the population of E. necator in Israel is composed of three genetic groups: Groups A and B that are common worldwide, and a new group IL, which is genetically differentiated from any known group in Europe and Eastern US. Group IL showed distinguished ecological characteristics: it was dominant on wild and traditional vines (95%); its abundance increased along the season; and was more aggressive than A and B isolates on both wild and domesticated vines. The low genetic diversity within group IL suggests that it has invaded Israel from another origin. Therefore, we suggest that the Israeli E. necator population was founded by at least two invasions, of which one could be from a non-East American source, possibly from Asian origin.
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Affiliation(s)
- Lior Gur
- Shamir Research Institute, University of Haifa, Katzrin, Israel.,Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel.,Department of Plant Pathology and Weed Research, Agricultural Research Organization (ARO), The Volcani Center, Rishon Lezion, Israel
| | - Moshe Reuveni
- Shamir Research Institute, University of Haifa, Katzrin, Israel
| | - Yigal Cohen
- Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Lance Cadle-Davidson
- USDA Agricultural Research Service, Geneva, NY, USA.,School of Integrative Plant Sciences, Cornell AgriTech, Geneva, NY, USA
| | - Breanne Kisselstein
- USDA Agricultural Research Service, Geneva, NY, USA.,School of Integrative Plant Sciences, Cornell AgriTech, Geneva, NY, USA
| | | | - Omer Frenkel
- Department of Plant Pathology and Weed Research, Agricultural Research Organization (ARO), The Volcani Center, Rishon Lezion, Israel
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8
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Acharya B, Ingram TW, Oh Y, Adhikari TB, Dean RA, Louws FJ. Opportunities and Challenges in Studies of Host-Pathogen Interactions and Management of Verticillium dahliae in Tomatoes. PLANTS (BASEL, SWITZERLAND) 2020; 9:E1622. [PMID: 33266395 PMCID: PMC7700276 DOI: 10.3390/plants9111622] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 12/14/2022]
Abstract
Tomatoes (Solanum lycopersicum L.) are a valuable horticultural crop that are grown and consumed worldwide. Optimal production is hindered by several factors, among which Verticillium dahliae, the cause of Verticillium wilt, is considered a major biological constraint in temperate production regions. V. dahliae is difficult to mitigate because it is a vascular pathogen, has a broad host range and worldwide distribution, and can persist in soil for years. Understanding pathogen virulence and genetic diversity, host resistance, and plant-pathogen interactions could ultimately inform the development of integrated strategies to manage the disease. In recent years, considerable research has focused on providing new insights into these processes, as well as the development and integration of environment-friendly management approaches. Here, we discuss the current knowledge on the race and population structure of V. dahliae, including pathogenicity factors, host genes, proteins, enzymes involved in defense, and the emergent management strategies and future research directions for managing Verticillium wilt in tomatoes.
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Affiliation(s)
- Bhupendra Acharya
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695, USA; (B.A.); (T.W.I.); (Y.Y.O.); (R.A.D.)
| | - Thomas W. Ingram
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695, USA; (B.A.); (T.W.I.); (Y.Y.O.); (R.A.D.)
| | - YeonYee Oh
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695, USA; (B.A.); (T.W.I.); (Y.Y.O.); (R.A.D.)
| | - Tika B. Adhikari
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695, USA; (B.A.); (T.W.I.); (Y.Y.O.); (R.A.D.)
| | - Ralph A. Dean
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695, USA; (B.A.); (T.W.I.); (Y.Y.O.); (R.A.D.)
| | - Frank J. Louws
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC 27695, USA; (B.A.); (T.W.I.); (Y.Y.O.); (R.A.D.)
- Department of Horticultural Science, North Carolina State University, Raleigh, NC 27695, USA
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9
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Wheeler DL, Johnson DA. Does Coinoculation with Different Verticillium dahliae Genotypes Affect the Host or Fungus? PHYTOPATHOLOGY 2019; 109:780-786. [PMID: 30614378 DOI: 10.1094/phyto-11-18-0430-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
Inferences about Verticillium dahliae are often deduced from experiments where hosts are inoculated with one isolate. The assumption that the outcomes from these experiments scale with V. dahliae diversity is untested. The objectives of this research were to test the hypotheses that (i) coinoculation with combinations of isolates affects plant biomass, disease expression, and fungal colonization; and (ii) hosts select for the specific isolates. Potato, mustard, and barley plants were coinoculated with seven combinations of three isolates. Genotypes recovered from infected plants were genotyped with microsatellite markers. Disease expression and fungal colonization but not plant biomass of potato was affected by coinoculation (F = 7.07, P < 0.0001; F = 2.36, P = 0.0427) and depended on the isolates with which plants were inoculated. One genotype was disproportionately selected for by all hosts. Putative heterokaryons were recovered from mustard plants coinoculated with isolates of different vegetative compatibility groups (VCG). These results support the assumption that mixed infections have marginal impacts on plant biomass but challenge the assumption that they do not affect disease expression and fungal colonization. Finally, this research provides evidence that plants select for specific V. dahliae genotypes and isolates from different VCGs can anastomose in planta.
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10
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Zhang D, Wang J, Wang D, Kong Z, Zhou L, Zhang G, Gui Y, Li J, Huang J, Wang B, Liu C, Yin C, Li R, Li T, Wang J, Short DPG, Klosterman SJ, Bostock RM, Subbarao KV, Chen J, Dai X. Population genomics demystifies the defoliation phenotype in the plant pathogen Verticillium dahliae. THE NEW PHYTOLOGIST 2019; 222:1012-1029. [PMID: 30609067 PMCID: PMC6594092 DOI: 10.1111/nph.15672] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 12/18/2018] [Indexed: 05/19/2023]
Abstract
Verticillium dahliae is a broad host-range pathogen that causes vascular wilts in plants. Interactions between three hosts and specific V. dahliae genotypes result in severe defoliation. The underlying mechanisms of defoliation are unresolved. Genome resequencing, gene deletion and complementation, gene expression analysis, sequence divergence, defoliating phenotype identification, virulence analysis, and quantification of V. dahliae secondary metabolites were performed. Population genomics previously revealed that G-LSR2 was horizontally transferred from the fungus Fusarium oxysporum f. sp. vasinfectum to V. dahliae and is exclusively found in the genomes of defoliating (D) strains. Deletion of seven genes within G-LSR2, designated as VdDf genes, produced the nondefoliation phenotype on cotton, olive, and okra but complementation of two genes restored the defoliation phenotype. Genes VdDf5 and VdDf6 associated with defoliation shared homology with polyketide synthases involved in secondary metabolism, whereas VdDf7 shared homology with proteins involved in the biosynthesis of N-lauroylethanolamine (N-acylethanolamine (NAE) 12:0), a compound that induces defoliation. NAE overbiosynthesis by D strains also appears to disrupt NAE metabolism in cotton by inducing overexpression of fatty acid amide hydrolase. The VdDfs modulate the synthesis and overproduction of secondary metabolites, such as NAE 12:0, that cause defoliation either by altering abscisic acid sensitivity, hormone disruption, or sensitivity to the pathogen.
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Affiliation(s)
- Dan‐Dan Zhang
- Laboratory of Crop Verticillium WiltInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Jie Wang
- Laboratory of Crop Verticillium WiltInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Dan Wang
- Laboratory of Crop Verticillium WiltInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Zhi‐Qiang Kong
- Laboratory of Crop Verticillium WiltInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Lei Zhou
- Laboratory of Crop Verticillium WiltInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | | | - Yue‐Jing Gui
- Laboratory of Crop Verticillium WiltInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Jun‐Jiao Li
- Laboratory of Crop Verticillium WiltInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | | | - Bao‐Li Wang
- Laboratory of Crop Verticillium WiltInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Chun Liu
- GenomicsBGI‐ShenzhenShenzhen518083China
| | - Chun‐Mei Yin
- Laboratory of Crop Verticillium WiltInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Rui‐Xing Li
- Laboratory of Crop Verticillium WiltInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Ting‐Gang Li
- Laboratory of Crop Verticillium WiltInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Jin‐Long Wang
- Department of BiologyDuke UniversityDurhamNC27708USA
| | - Dylan P. G. Short
- Department of Plant PathologyUniversity of California, Davisc/o US Agricultural Research StationSalinasCA93905USA
| | - Steven J. Klosterman
- United States Department of AgricultureAgricultural Research ServiceCrop Improvement and Protection Research UnitSalinasCA93905USA
| | | | - Krishna V. Subbarao
- Department of Plant PathologyUniversity of California, Davisc/o US Agricultural Research StationSalinasCA93905USA
| | - Jie‐Yin Chen
- Laboratory of Crop Verticillium WiltInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Xiao‐Feng Dai
- Laboratory of Crop Verticillium WiltInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
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11
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Baroudy F, Putman AI, Habib W, Puri KD, Subbarao KV, Nigro F. Genetic Diversity of Verticillium dahliae Populations From Olive and Potato in Lebanon. PLANT DISEASE 2019; 103:656-667. [PMID: 30823856 DOI: 10.1094/pdis-03-18-0420-re] [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
Verticillium dahliae is widely distributed in potato and olive fields in Lebanon, causing serious economic losses. However, little is known about the inoculum source, population structure, and genetic diversity of the pathogen or the mechanisms of dissemination within Lebanon. To understand the population structure, a total of 203 isolates sampled from olive (n = 78) and potato (n = 125) were characterized for species, mating type, and race, and the genetic relationships were delineated using 13 microsatellite markers. All isolates except one from potato were V. dahliae, with 55.1 and 12.1% race 1, and 43.6 and 83.1% race 2 in olive and potato, respectively. The genetic structure of the studied population was best described by two large and two small clusters. Membership in the two large clusters was determined by the presence or absence of the effector gene Ave1. Furthermore, genetic structure was moderately associated with the host of origin but was weakly associated with the geographic origin. All but four isolates represented by three multilocus haploid genotypes were MAT1-2. This study identified a clear lack of gene flow between virulence genotypes of V. dahliae despite the proximity of these cropping systems and the wide distribution of genetic diversity among hosts and geographic regions in Lebanon.
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Affiliation(s)
- Farah Baroudy
- 1 Dipartimento di Scienze del Suolo, Università degli Studi di Bari - Aldo Moro, Bari, 70126 Bari, Italy
- 2 Lebanese Agricultural Research Institute, Laboratory of Mycology, Department of Plant Protection, Fanar, Jdeidet El Metn, Lebanon
| | - Alexander I Putman
- 3 Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521, U.S.A.; and
| | - Wassim Habib
- 2 Lebanese Agricultural Research Institute, Laboratory of Mycology, Department of Plant Protection, Fanar, Jdeidet El Metn, Lebanon
| | - Krishna D Puri
- 4 Department of Plant Pathology, University of California, Davis, c/o U.S. Agricultural Research Station, Salinas, CA 93905, U.S.A
| | - Krishna V Subbarao
- 4 Department of Plant Pathology, University of California, Davis, c/o U.S. Agricultural Research Station, Salinas, CA 93905, U.S.A
| | - Franco Nigro
- 1 Dipartimento di Scienze del Suolo, Università degli Studi di Bari - Aldo Moro, Bari, 70126 Bari, Italy
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12
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Pais M, Yoshida K, Giannakopoulou A, Pel MA, Cano LM, Oliva RF, Witek K, Lindqvist-Kreuze H, Vleeshouwers VGAA, Kamoun S. Gene expression polymorphism underpins evasion of host immunity in an asexual lineage of the Irish potato famine pathogen. BMC Evol Biol 2018; 18:93. [PMID: 29973156 PMCID: PMC6032779 DOI: 10.1186/s12862-018-1201-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 05/22/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Outbreaks caused by asexual lineages of fungal and oomycete pathogens are a continuing threat to crops, wild animals and natural ecosystems (Fisher MC, Henk DA, Briggs CJ, Brownstein JS, Madoff LC, McCraw SL, Gurr SJ, Nature 484:186-194, 2012; Kupferschmidt K, Science 337:636-638, 2012). However, the mechanisms underlying genome evolution and phenotypic plasticity in asexual eukaryotic microbes remain poorly understood (Seidl MF, Thomma BP, BioEssays 36:335-345, 2014). Ever since the 19th century Irish famine, the oomycete Phytophthora infestans has caused recurrent outbreaks on potato and tomato crops that have been primarily caused by the successive rise and migration of pandemic asexual lineages (Goodwin SB, Cohen BA, Fry WE, Proc Natl Acad Sci USA 91:11591-11595, 1994; Yoshida K, Burbano HA, Krause J, Thines M, Weigel D, Kamoun S, PLoS Pathog 10:e1004028, 2014; Yoshida K, Schuenemann VJ, Cano LM, Pais M, Mishra B, Sharma R, Lanz C, Martin FN, Kamoun S, Krause J, et al. eLife 2:e00731, 2013; Cooke DEL, Cano LM, Raffaele S, Bain RA, Cooke LR, Etherington GJ, Deahl KL, Farrer RA, Gilroy EM, Goss EM, et al. PLoS Pathog 8:e1002940, 2012). However, the dynamics of genome evolution within these clonal lineages have not been determined. The objective of this study was to use a comparative genomics and transcriptomics approach to determine the molecular mechanisms that underpin phenotypic variation within a clonal lineage of P. infestans. RESULTS Here, we reveal patterns of genomic and gene expression variation within a P. infestans asexual lineage by comparing strains belonging to the South American EC-1 clone that has dominated Andean populations since the 1990s (Yoshida K, Burbano HA, Krause J, Thines M, Weigel D, Kamoun S, PLoS Pathog 10e1004028, 2014; Yoshida K, Schuenemann VJ, Cano LM, Pais M, Mishra B, Sharma R, Lanz C, Martin FN, Kamoun S, Krause J, et al. eLife 2:e00731, 2013; Delgado RA, Monteros-Altamirano AR, Li Y, Visser RGF, van der Lee TAJ, Vosman B, Plant Pathol 62:1081-1088, 2013; Forbes GA, Escobar XC, Ayala CC, Revelo J, Ordonez ME, Fry BA, Doucett K, Fry WE, Phytopathology 87:375-380, 1997; Oyarzun PJ, Pozo A, Ordonez ME, Doucett K, Forbes GA, Phytopathology 88:265-271, 1998). We detected numerous examples of structural variation, nucleotide polymorphisms and loss of heterozygosity within the EC-1 clone. Remarkably, 17 genes are not expressed in one of the two EC-1 isolates despite apparent absence of sequence polymorphisms. Among these, silencing of an effector gene was associated with evasion of disease resistance conferred by a potato immune receptor. CONCLUSIONS Our findings highlight the molecular changes underpinning the exceptional genetic and phenotypic plasticity associated with host adaptation in a pandemic clonal lineage of a eukaryotic plant pathogen. We observed that the asexual P. infestans lineage EC-1 can exhibit phenotypic plasticity in the absence of apparent genetic mutations resulting in virulence on a potato carrying the Rpi-vnt1.1 gene. Such variant alleles may be epialleles that arose through epigenetic changes in the underlying genes.
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Affiliation(s)
- Marina Pais
- The Sainsbury Laboratory, Norwich Research Park, Colney Ln, Norwich, NR4 7UH UK
| | - Kentaro Yoshida
- The Sainsbury Laboratory, Norwich Research Park, Colney Ln, Norwich, NR4 7UH UK
- Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Artemis Giannakopoulou
- The Sainsbury Laboratory, Norwich Research Park, Colney Ln, Norwich, NR4 7UH UK
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry & Biotechnology, Athens, Greece
| | - Mathieu A. Pel
- Wageningen UR Plant Breeding, Wageningen, The Netherlands
| | - Liliana M. Cano
- The Sainsbury Laboratory, Norwich Research Park, Colney Ln, Norwich, NR4 7UH UK
- Institute of Food and Agricultural Sciences, Department of Plant Pathology, Indian River Research and Education Center, University of Florida, Fort Pierce, FL USA
| | - Ricardo F. Oliva
- The Sainsbury Laboratory, Norwich Research Park, Colney Ln, Norwich, NR4 7UH UK
- Genetics and Biotechnology Division, International Rice Research Institute, Los Baños, Philippines
| | - Kamil Witek
- The Sainsbury Laboratory, Norwich Research Park, Colney Ln, Norwich, NR4 7UH UK
| | | | | | - Sophien Kamoun
- The Sainsbury Laboratory, Norwich Research Park, Colney Ln, Norwich, NR4 7UH UK
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13
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Silva DN, Várzea V, Paulo OS, Batista D. Population genomic footprints of host adaptation, introgression and recombination in coffee leaf rust. MOLECULAR PLANT PATHOLOGY 2018; 19:1742-1753. [PMID: 29328532 PMCID: PMC6638104 DOI: 10.1111/mpp.12657] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 01/04/2018] [Accepted: 01/09/2018] [Indexed: 05/30/2023]
Abstract
Coffee leaf rust, caused by Hemileia vastatrix (Hv), represents the biggest threat to coffee production worldwide and ranks amongst the most serious fungal diseases in history. Despite a recent series of outbreaks and emergence of hypervirulent strains, the population evolutionary history and potential of this pathogen remain poorly understood. To address this issue, we used restriction site-associated DNA sequencing (RADseq) to generate ∼19 000 single nucleotide polymorphisms (SNPs) across a worldwide collection of 37 Hv samples. Contrary to the long-standing idea that Hv represents a genetically unstructured and cosmopolitan species, our results reveal the existence of a cryptic species complex with marked host tropism. Using phylogenetic and pathological data, we show that one of these lineages (C3) infects almost exclusively the most economically valuable coffee species (tetraploids that include Coffea arabica and interspecific hybrids), whereas the other lineages (C1 and C2) are severely maladapted to these hosts, but successfully infect diploid coffee species. Population dynamic analyses suggest that the C3 group may be a recent 'domesticated' lineage that emerged via host shift from diploid coffee hosts. We also found evidence of recombination occurring within this group, which could explain the high pace of pathotype emergence despite the low genetic variation. Moreover, genomic footprints of introgression between the C3 and C2 groups were discovered and raise the possibility that virulence factors may be quickly exchanged between groups with different pathogenic abilities. This work advances our understanding of the evolutionary strategies used by plant pathogens in agro-ecosystems with direct and far-reaching implications for disease control.
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Affiliation(s)
- Diogo Nuno Silva
- Departamento de Biologia Animal, Centre for Ecology, Evolution and Environmental Changes (cE3c), Computational Biology and Population Genomics Group (CoBiG)Faculdade de Ciências, Universidade de LisboaLisboaPortugal
- Centro de Investigação das Ferrugens do Cafeeiro (CIFC), Instituto Superior de AgronomiaUniversidade de LisboaOeirasPortugal
- Linking Landscape, Environment, Agriculture and Food (LEAF), Instituto Superior de AgronomiaUniversidade de LisboaLisboaPortugal
| | - Vítor Várzea
- Centro de Investigação das Ferrugens do Cafeeiro (CIFC), Instituto Superior de AgronomiaUniversidade de LisboaOeirasPortugal
- Linking Landscape, Environment, Agriculture and Food (LEAF), Instituto Superior de AgronomiaUniversidade de LisboaLisboaPortugal
| | - Octávio Salgueiro Paulo
- Departamento de Biologia Animal, Centre for Ecology, Evolution and Environmental Changes (cE3c), Computational Biology and Population Genomics Group (CoBiG)Faculdade de Ciências, Universidade de LisboaLisboaPortugal
| | - Dora Batista
- Departamento de Biologia Animal, Centre for Ecology, Evolution and Environmental Changes (cE3c), Computational Biology and Population Genomics Group (CoBiG)Faculdade de Ciências, Universidade de LisboaLisboaPortugal
- Centro de Investigação das Ferrugens do Cafeeiro (CIFC), Instituto Superior de AgronomiaUniversidade de LisboaOeirasPortugal
- Linking Landscape, Environment, Agriculture and Food (LEAF), Instituto Superior de AgronomiaUniversidade de LisboaLisboaPortugal
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14
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Meng JW, He DC, Zhu W, Yang LN, Wu EJ, Xie JH, Shang LP, Zhan J. Human-Mediated Gene Flow Contributes to Metapopulation Genetic Structure of the Pathogenic Fungus Alternaria alternata from Potato. FRONTIERS IN PLANT SCIENCE 2018; 9:198. [PMID: 29497439 PMCID: PMC5818430 DOI: 10.3389/fpls.2018.00198] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 02/01/2018] [Indexed: 06/01/2023]
Abstract
Metapopulation structure generated by recurrent extinctions and recolonizations plays an important role in the evolution of species but is rarely considered in agricultural systems. In this study, generation and mechanism of metapopulation structure were investigated by microsatellite assaying 725 isolates of Alternaria alternata sampled from potato hosts at 16 locations across China. We found a single major cluster, no isolate-geography associations and no bottlenecks in the A. alternata isolates, suggesting a metapopulation genetic structure of the pathogen. We also found weak isolation-by-distance, lower among than within cropping region population differentiation, concordant moving directions of potato products and net gene flow and the highest gene diversity in the region with the most potato imports. These results indicate that in addition to natural dispersal, human-mediated gene flow also contributes to the generation and dynamics of the metapopulation genetic structure of A. alternata in China. Metapopulation structure increases the adaptive capacity of the plant pathogen as a result of enhanced genetic variation and reduced population fragmentation. Consequently, rigid quarantine regulations may be required to reduce population connectivity and the evolutionary potential of A. alternata and other pathogens with a similar population dynamics for a sustainable plant disease management.
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Affiliation(s)
- Jing-Wen Meng
- Fujian Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Dun-Chun He
- Fujian Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Wen Zhu
- Fujian Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Li-Na Yang
- Fujian Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - E-Jiao Wu
- Fujian Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jia-Hui Xie
- Fujian Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Li-Ping Shang
- Fujian Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jiasui Zhan
- Fujian Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China
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15
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Carroll CL, Carter CA, Goodhue RE, Lawell CYCL, Subbarao KV. A Review of Control Options and Externalities for Verticillium Wilts. PHYTOPATHOLOGY 2018; 108:160-171. [PMID: 28703041 DOI: 10.1094/phyto-03-17-0083-rvw] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Plant pathogens migrate to new regions through human activities such as trade, where they may establish themselves and cause disease on agriculturally important crops. Verticillium wilt of lettuce, caused by Verticillium dahliae, is a soilborne fungus that was introduced to coastal California via infested spinach seeds. It has caused significant losses for lettuce growers. Once introduced, Verticillium wilt could be managed by fumigating with methyl bromide and chloropicrin, but this option is no longer available. Growers can also manage the disease by planting broccoli or not planting spinach. These control options require long-term investments for future gain. Verticillium wilt can also be prevented or controlled by testing and providing spinach seeds with little or no V. dahliae infestation. However, seed companies have been reluctant to test or clean spinach seeds, as spinach crops are not affected by Verticillium wilt. Thus, available control options are affected by externalities. Renters and other producers with short time horizons will not undertake long-term investments and seed companies do not take into account the effect of their decision not to test on lettuce producers. We review the literature on the economics of managing crop disease; discuss the economics of managing Verticillium wilt; and review the recent research on the externalities that arise with short-term growers, and between seed companies and growers due to Verticillium wilt. An externality arises whenever the actions of one individual or firm affects the payoffs to another individual or firm not involved in a specific transaction. These externalities have important implications for the management of Verticillium wilt and, more broadly, for the management of migratory pathogens and the diseases they cause in agriculture in general. This review is of interest to policy-makers, the producers, marketers, seed companies, and researchers.
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Affiliation(s)
- Christine L Carroll
- First author: College of Agriculture, California State University, Chico 95929; second and third authors: Department of Agricultural and Resource Economics, University of California, One Shields Avenue, Davis 95616; fourth author: Charles H. Dyson School of Applied Economics and Management, 407 Warren Hall, Cornell University, Ithaca, NY 14853; and fifth author: Department of Plant Pathology, University of California, Davis, c/o U.S. Agricultural Research Station, 1636 E. Alisal Street, Salinas 95616
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16
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Chen J, Liu C, Gui Y, Si K, Zhang D, Wang J, Short DPG, Huang J, Li N, Liang Y, Zhang W, Yang L, Ma X, Li T, Zhou L, Wang B, Bao Y, Subbarao KV, Zhang G, Dai X. Comparative genomics reveals cotton-specific virulence factors in flexible genomic regions in Verticillium dahliae and evidence of horizontal gene transfer from Fusarium. THE NEW PHYTOLOGIST 2018; 217:756-770. [PMID: 29084346 PMCID: PMC5765495 DOI: 10.1111/nph.14861] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 09/21/2017] [Indexed: 05/20/2023]
Abstract
Verticillium dahliae isolates are most virulent on the host from which they were originally isolated. Mechanisms underlying these dominant host adaptations are currently unknown. We sequenced the genome of V. dahliae Vd991, which is highly virulent on its original host, cotton, and performed comparisons with the reference genomes of JR2 (from tomato) and VdLs.17 (from lettuce). Pathogenicity-related factor prediction, orthology and multigene family classification, transcriptome analyses, phylogenetic analyses, and pathogenicity experiments were performed. The Vd991 genome harbored several exclusive, lineage-specific (LS) genes within LS regions (LSRs). Deletion mutants of the seven genes within one LSR (G-LSR2) in Vd991 were less virulent only on cotton. Integration of G-LSR2 genes individually into JR2 and VdLs.17 resulted in significantly enhanced virulence on cotton but did not affect virulence on tomato or lettuce. Transcription levels of the seven LS genes in Vd991 were higher during the early stages of cotton infection, as compared with other hosts. Phylogenetic analyses suggested that G-LSR2 was acquired from Fusarium oxysporum f. sp. vasinfectum through horizontal gene transfer. Our results provide evidence that horizontal gene transfer from Fusarium to Vd991 contributed significantly to its adaptation to cotton and may represent a significant mechanism in the evolution of an asexual plant pathogen.
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Affiliation(s)
- Jie‐Yin Chen
- Laboratory of Cotton DiseaseInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Chun Liu
- BGI‐ShenzhenShenzhenGuangdong518083China
| | - Yue‐Jing Gui
- Laboratory of Cotton DiseaseInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Kai‐Wei Si
- BGI‐ShenzhenShenzhenGuangdong518083China
| | - Dan‐Dan Zhang
- Laboratory of Cotton DiseaseInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Jie Wang
- Laboratory of Cotton DiseaseInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Dylan P. G. Short
- Department of Plant PathologyUniversity of CaliforniaDavisCA95616USA
| | | | - Nan‐Yang Li
- Laboratory of Cotton DiseaseInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Yong Liang
- BGI‐ShenzhenShenzhenGuangdong518083China
| | - Wen‐Qi Zhang
- Laboratory of Cotton DiseaseInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Lin Yang
- BGI‐ShenzhenShenzhenGuangdong518083China
| | - Xue‐Feng Ma
- Laboratory of Cotton DiseaseInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Ting‐Gang Li
- Laboratory of Cotton DiseaseInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Lei Zhou
- Laboratory of Cotton DiseaseInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Bao‐Li Wang
- Laboratory of Cotton DiseaseInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | - Yu‐Ming Bao
- Laboratory of Cotton DiseaseInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
| | | | | | - Xiao‐Feng Dai
- Laboratory of Cotton DiseaseInstitute of Food Science and TechnologyChinese Academy of Agricultural SciencesBeijing100193China
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17
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Zhao J, Liu J, Xu J, Zhao L, Wu Q, Xiao S. Quantitative Trait Locus Mapping and Candidate Gene Analysis for Verticillium Wilt Resistance Using Gossypium barbadense Chromosomal Segment Introgressed Line. FRONTIERS IN PLANT SCIENCE 2018; 9:682. [PMID: 29899750 PMCID: PMC5988901 DOI: 10.3389/fpls.2018.00682] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 05/03/2018] [Indexed: 05/08/2023]
Abstract
Verticillium wilt (VW) is a soil-borne fungal disease that is caused by Verticillium dahliae Kleb and seriously damages cotton production annually in China. To date, many efforts have been made to improve the resistance of upland cotton against VW, but little progress has been achieved because of a lack of resistant upland cotton to VW. G. barbadense is known to carry high resistance to VW; however, it is difficult to transfer the resistance trait from G. barbadense to upland cotton because of linkage drag and distortion in the interspecific hybrid. In this study, a chromosomal segment introgression line (CSIL), SuVR043, containing a single and homozygous chromosome segment of G. barbadense cv. H7124 D04 (Chr 22), was created and used to construct an F2 population for mapping of VW resistance quantitative trait loci (QTLs) in the greenhouse. Two major resistance QTLs against nondefoliating V. dahliae isolate Bp2, called qVW-Bp2-1 and qVW-Bp2-2, which were flanked by the markers cgr6409-ZHX37 and ZHX57-ZHX70 and explained an average of 16.38 and 22.36% of the observed phenotypic variation, respectively, were detected in three independent replicate experiments. The genetic distances from cgr6409 to ZHX37 and from ZHX57 to ZHX70 were 2.4 and 0.8 cM, respectively. By analyzing the genome sequence of the qVW-Bp2-1 and qVW-Bp2-2 regions, we determined that the accurate physical distances from cgr6409 to ZHX37 and from ZHX57 to ZHX70 in the G. barbadense genome are 254 and 140 kb, and that those spans 36 and 20 putative genes, respectively. The results of the expression analysis showed significant differences in the expression profiles of GbCYP450, GbTMEM214, and GbRLK among G. barbadense cv. H7124, CSIL SuVR043 and G. hirsutum acc. Sumian 8 at different times after inoculation with V. dahliae isolate Bp2. Virus-induced gene silencing (VIGS) analysis showed that silencing of GbCYP450 and GbTMEM214 decreased H7124 and CSIL SuVR043 resistance to VW. These results form a solid foundation for fine mapping and cloning of resistance genes in the substituted segment and will provide valuable assistance in future efforts to breed for VW resistance.
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Affiliation(s)
- Jun Zhao
- Key Laboratory of Cotton and Rapeseed, Ministry of Agriculture, Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Jianguang Liu
- Key Laboratory of Cotton and Rapeseed, Ministry of Agriculture, Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Jianwen Xu
- Key Laboratory of Cotton and Rapeseed, Ministry of Agriculture, Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Liang Zhao
- Key Laboratory of Cotton and Rapeseed, Ministry of Agriculture, Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Qiaojuan Wu
- Key Laboratory of Cotton and Rapeseed, Ministry of Agriculture, Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Songhua Xiao
- Key Laboratory of Cotton and Rapeseed, Ministry of Agriculture, Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- *Correspondence: Songhua Xiao
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Puri KD, Gurung S, Short DPG, Atallah ZK, Sandoya G, Davis RM, Hayes RJ, Subbarao KV. Short-Term Host Selection Pressure Has Little Effect on the Evolution of a Monoclonal Population of Verticillium dahliae Race 1. PHYTOPATHOLOGY 2017; 107:1417-1425. [PMID: 28653580 DOI: 10.1094/phyto-02-17-0071-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Understanding pathogen evolution over time is vital for plant breeding and deployment of host resistance. In the context of a soilborne pathogen, the potential of host-directed evolution of a Verticillium dahliae race 1 isolate and genotypic variation of V. dahliae associated with two major hosts (lettuce and tomato) were determined. In total, 427 isolates were recovered over 6 years from a resistance screening nursery infested with a single V. dahliae race 1 isolate. In a separate study, an additional 206 isolates representing 163 and 43 isolates from commercial lettuce and tomato fields, respectively, were collected. Analyses of isolates recovered from the screening nursery over 6 years revealed no changes in the race and mating type composition but did uncover seven simple sequence repeat (SSR) variant genotypes. No significant genotypic variation in V. dahliae was observed between or within fields of either lettuce or tomato but pathogen populations were significantly differentiated between these two hosts. Replicated virulence assays of variant SSR genotypes on lettuce differential cultivars suggested no significant difference in virulence from the wild-type race 1 isolate introduced into the field. This suggests that deployed race 1 host resistance will be robust against the widespread race 1 populations in lettuce-growing regions at least for 6 years unless novel pathogen genotypes or races are introduced into the system.
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Affiliation(s)
- Krishna D Puri
- First, third, sixth, and eighth authors: Department of Plant Pathology, University of California, Davis; second author: Sakata Seed America, Salinas, CA; fourth author: Hartnell College, Salinas, CA 93905; fifth author: Department of Horticultural Science, Everglades Research and Education Center, University of Florida, Belle Glade; and seventh author: United States Department of Agriculture-Agricultural Research Service, Salinas, CA
| | - Suraj Gurung
- First, third, sixth, and eighth authors: Department of Plant Pathology, University of California, Davis; second author: Sakata Seed America, Salinas, CA; fourth author: Hartnell College, Salinas, CA 93905; fifth author: Department of Horticultural Science, Everglades Research and Education Center, University of Florida, Belle Glade; and seventh author: United States Department of Agriculture-Agricultural Research Service, Salinas, CA
| | - Dylan P G Short
- First, third, sixth, and eighth authors: Department of Plant Pathology, University of California, Davis; second author: Sakata Seed America, Salinas, CA; fourth author: Hartnell College, Salinas, CA 93905; fifth author: Department of Horticultural Science, Everglades Research and Education Center, University of Florida, Belle Glade; and seventh author: United States Department of Agriculture-Agricultural Research Service, Salinas, CA
| | - Z K Atallah
- First, third, sixth, and eighth authors: Department of Plant Pathology, University of California, Davis; second author: Sakata Seed America, Salinas, CA; fourth author: Hartnell College, Salinas, CA 93905; fifth author: Department of Horticultural Science, Everglades Research and Education Center, University of Florida, Belle Glade; and seventh author: United States Department of Agriculture-Agricultural Research Service, Salinas, CA
| | - German Sandoya
- First, third, sixth, and eighth authors: Department of Plant Pathology, University of California, Davis; second author: Sakata Seed America, Salinas, CA; fourth author: Hartnell College, Salinas, CA 93905; fifth author: Department of Horticultural Science, Everglades Research and Education Center, University of Florida, Belle Glade; and seventh author: United States Department of Agriculture-Agricultural Research Service, Salinas, CA
| | - R Michael Davis
- First, third, sixth, and eighth authors: Department of Plant Pathology, University of California, Davis; second author: Sakata Seed America, Salinas, CA; fourth author: Hartnell College, Salinas, CA 93905; fifth author: Department of Horticultural Science, Everglades Research and Education Center, University of Florida, Belle Glade; and seventh author: United States Department of Agriculture-Agricultural Research Service, Salinas, CA
| | - Ryan J Hayes
- First, third, sixth, and eighth authors: Department of Plant Pathology, University of California, Davis; second author: Sakata Seed America, Salinas, CA; fourth author: Hartnell College, Salinas, CA 93905; fifth author: Department of Horticultural Science, Everglades Research and Education Center, University of Florida, Belle Glade; and seventh author: United States Department of Agriculture-Agricultural Research Service, Salinas, CA
| | - Krishna V Subbarao
- First, third, sixth, and eighth authors: Department of Plant Pathology, University of California, Davis; second author: Sakata Seed America, Salinas, CA; fourth author: Hartnell College, Salinas, CA 93905; fifth author: Department of Horticultural Science, Everglades Research and Education Center, University of Florida, Belle Glade; and seventh author: United States Department of Agriculture-Agricultural Research Service, Salinas, CA
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Choudhury RA, Garrett KA, Klosterman SJ, Subbarao KV, McRoberts N. A Framework for Optimizing Phytosanitary Thresholds in Seed Systems. PHYTOPATHOLOGY 2017; 107:1219-1228. [PMID: 28726578 DOI: 10.1094/phyto-04-17-0131-fi] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Seedborne pathogens and pests limit production in many agricultural systems. Quarantine programs help prevent the introduction of exotic pathogens into a country, but few regulations directly apply to reducing the reintroduction and spread of endemic pathogens. Use of phytosanitary thresholds helps limit the movement of pathogen inoculum through seed, but the costs associated with rejected seed lots can be prohibitive for voluntary implementation of phytosanitary thresholds. In this paper, we outline a framework to optimize thresholds for seedborne pathogens, balancing the cost of rejected seed lots and benefit of reduced inoculum levels. The method requires relatively small amounts of data, and the accuracy and robustness of the analysis improves over time as data accumulate from seed testing. We demonstrate the method first and illustrate it with a case study of seedborne oospores of Peronospora effusa, the causal agent of spinach downy mildew. A seed lot threshold of 0.23 oospores per seed could reduce the overall number of oospores entering the production system by 90% while removing 8% of seed lots destined for distribution. Alternative mitigation strategies may result in lower economic losses to seed producers, but have uncertain efficacy. We discuss future challenges and prospects for implementing this approach.
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Affiliation(s)
- Robin Alan Choudhury
- First and second authors: Plant Pathology Department, Institute for Sustainable Food Systems, and Emerging Pathogens Institute, University of Florida, Gainesville 32611; third author: U.S. Department of Agriculture-Agricultural Research Service, 1636 E. Alisal St., Salinas 93905; and first, fourth, and fifth authors: Department of Plant Pathology, University of California, Davis 95616
| | - Karen A Garrett
- First and second authors: Plant Pathology Department, Institute for Sustainable Food Systems, and Emerging Pathogens Institute, University of Florida, Gainesville 32611; third author: U.S. Department of Agriculture-Agricultural Research Service, 1636 E. Alisal St., Salinas 93905; and first, fourth, and fifth authors: Department of Plant Pathology, University of California, Davis 95616
| | - Steven J Klosterman
- First and second authors: Plant Pathology Department, Institute for Sustainable Food Systems, and Emerging Pathogens Institute, University of Florida, Gainesville 32611; third author: U.S. Department of Agriculture-Agricultural Research Service, 1636 E. Alisal St., Salinas 93905; and first, fourth, and fifth authors: Department of Plant Pathology, University of California, Davis 95616
| | - Krishna V Subbarao
- First and second authors: Plant Pathology Department, Institute for Sustainable Food Systems, and Emerging Pathogens Institute, University of Florida, Gainesville 32611; third author: U.S. Department of Agriculture-Agricultural Research Service, 1636 E. Alisal St., Salinas 93905; and first, fourth, and fifth authors: Department of Plant Pathology, University of California, Davis 95616
| | - Neil McRoberts
- First and second authors: Plant Pathology Department, Institute for Sustainable Food Systems, and Emerging Pathogens Institute, University of Florida, Gainesville 32611; third author: U.S. Department of Agriculture-Agricultural Research Service, 1636 E. Alisal St., Salinas 93905; and first, fourth, and fifth authors: Department of Plant Pathology, University of California, Davis 95616
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Gao F, Zou W, Xie L, Zhan J. Adaptive evolution and demographic history contribute to the divergent population genetic structure of Potato virus Y between China and Japan. Evol Appl 2017; 10:379-390. [PMID: 28352297 PMCID: PMC5367074 DOI: 10.1111/eva.12459] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 01/10/2017] [Indexed: 12/22/2022] Open
Abstract
Potato virus Y (PVY) is an important plant pathogen causing considerable economic loss to potato production. Knowledge of the population genetic structure and evolutionary biology of the pathogen, particularly at a transnational scale, is limited but vital in developing sustainable management schemes. In this study, the population genetic structure and molecular evolution of PVY were studied using 127 first protein (P1) and 137 coat protein (CP) sequences generated from isolates collected from potato in China and Japan. High genetic differentiation was found between the populations from the two countries, with higher nucleotide diversity in Japan than China in both genes and a KST value of .216 in the concatenated sequences of the two genes. Sequences from the two countries clustered together according to their geographic origin. Further analyses showed that spatial genetic structure in the PVY populations was likely caused by demographic dynamics of the pathogen and natural selection generated by habitat heterogeneity. Purifying selection was detected at the majority of polymorphic sites although some clade-specific codons were under positive selection. In past decades, PVY has undergone a population expansion in China, whereas in Japan, the population size of the pathogen has remained relatively constant.
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Affiliation(s)
- Fangluan Gao
- Fujian Key Laboratory of Plant VirologyInstitute of Plant VirologyFujian Agriculture and Forestry UniversityFuzhouChina
| | - Wenchao Zou
- Fujian Key Laboratory of Plant VirologyInstitute of Plant VirologyFujian Agriculture and Forestry UniversityFuzhouChina
| | - Lianhui Xie
- Fujian Key Laboratory of Plant VirologyInstitute of Plant VirologyFujian Agriculture and Forestry UniversityFuzhouChina
| | - Jiasui Zhan
- Fujian Key Laboratory of Plant VirologyInstitute of Plant VirologyFujian Agriculture and Forestry UniversityFuzhouChina
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Abstract
Fungal plant pathogens are ubiquitous and highly diverse. Key to their success is high host density, which notably is the case in agroecosystems. Several hypotheses related to the effects of plant pathogens on plant diversity (the Janzen-Connell hypothesis, the dilution effect hypothesis) and the phenomenon of higher biomass in plant mixtures (i.e., overyielding) can all be explained by the quantitative interplay between host and pathogen density. In many agroecosystems, fungal plant pathogens cause great losses, since in monocultures diseased plants cannot be replaced by healthy plants. On the other hand, in natural ecosystems fungal plant pathogens shape the succession of vegetation and enhance the biodiversity of forests and grasslands. When pathogens are introduced into areas outside their natural range, they may behave differently, causing severe damage. Once introduced, changes may occur such as hybridization with other closely related pathogens or host shifts, host jumps, or horizontal gene transfer. Such changes can be hazardous for both agricultural and natural ecosystems.
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Milgroom MG, Del Mar Jiménez-Gasco M, Olivares-García C, Jiménez-Díaz RM. Clonal Expansion and Migration of a Highly Virulent, Defoliating Lineage of Verticillium dahliae. PHYTOPATHOLOGY 2016; 106:1038-46. [PMID: 27050569 DOI: 10.1094/phyto-11-15-0300-r] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We used a population genomics approach to test the hypothesis of clonal expansion of a highly fit genotype in populations of Verticillium dahliae. This fungal pathogen has a broad host range and can be dispersed in contaminated seed or other plant material. It has a highly clonal population structure, with several lineages having nearly worldwide distributions in agricultural crops. Isolates in lineage 1A are highly virulent and cause defoliation in cotton, okra, and olive (denoted 1A/D), whereas those in other lineages cause wilting but not defoliation (ND). We tested whether the highly virulent lineage 1A/D could have spread from the southwestern United States to the Mediterranean basin, as predicted from historical records. We found 187 single-nucleotide polymorphisms (SNPs), determined by genotyping by sequencing, among 91 isolates of lineage 1A/D and 5 isolates in the closely related lineage 1B/ND. Neighbor-joining and maximum-likelihood analyses on the 187 SNPs showed a clear divergence between 1A/D and 1B/ND haplotypes. Data for only 77 SNPs were obtained for all 96 isolates (no missing data); lineages 1A/D and 1B/ND differed by 27 of these 77 SNPs, confirming a clear divergence between the two lineages. No evidence of recombination was detected within or between these two lineages. Phylogenetic and genealogical analyses resulted in five distinct subclades of 1A/D isolates that correlated closely with geographic origins in the Mediterranean basin, consistent with the hypothesis that the D pathotype was introduced at least five times in independent founder events into this region from a relatively diverse source population. The inferred ancestral haplotype was found in two isolates sampled before 1983 from the southwestern United States, which is consistent with historical records that 1A/D originated in North America. The five subclades coalesce with the ancestral haplotype at the same time, consistent with a hypothesis of rapid population expansion in the source population during the emergence of 1A/D as a severe pathogen of cotton in the United States.
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Affiliation(s)
- Michael G Milgroom
- First author: Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853; second author: Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802; and third and fourth authors: College of Agriculture and Forestry (ETSIAM), University of Córdoba, and Institute for Sustainable Agriculture (IAS), CSIC, Campus de Excelencia Internacional Agroalimentario, ceiA3, P.O. Box 4084, 14080, Córdoba, Spain
| | - María Del Mar Jiménez-Gasco
- First author: Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853; second author: Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802; and third and fourth authors: College of Agriculture and Forestry (ETSIAM), University of Córdoba, and Institute for Sustainable Agriculture (IAS), CSIC, Campus de Excelencia Internacional Agroalimentario, ceiA3, P.O. Box 4084, 14080, Córdoba, Spain
| | - Concepción Olivares-García
- First author: Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853; second author: Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802; and third and fourth authors: College of Agriculture and Forestry (ETSIAM), University of Córdoba, and Institute for Sustainable Agriculture (IAS), CSIC, Campus de Excelencia Internacional Agroalimentario, ceiA3, P.O. Box 4084, 14080, Córdoba, Spain
| | - Rafael M Jiménez-Díaz
- First author: Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853; second author: Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802; and third and fourth authors: College of Agriculture and Forestry (ETSIAM), University of Córdoba, and Institute for Sustainable Agriculture (IAS), CSIC, Campus de Excelencia Internacional Agroalimentario, ceiA3, P.O. Box 4084, 14080, Córdoba, Spain
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23
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Ashu EE, Xu J. The roles of sexual and asexual reproduction in the origin and dissemination of strains causing fungal infectious disease outbreaks. INFECTION GENETICS AND EVOLUTION 2015; 36:199-209. [PMID: 26394109 DOI: 10.1016/j.meegid.2015.09.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 09/16/2015] [Accepted: 09/18/2015] [Indexed: 12/15/2022]
Abstract
Sexual reproduction commonly refers to the reproductive process in which genomes from two sources are combined into a single cell through mating and then the zygote genomes are partitioned to progeny cells through meiosis. Reproduction in the absence of mating and meiosis is referred to as asexual or clonal reproduction. One major advantage of sexual reproduction is that it generates genetic variation among progeny which may allow for faster adaptation of the population to novel and/or stressful environments. However, adaptation to stressful or new environments can still occur through mutation, in the absence of sex. In this review, we analyzed the relative contributions of sexual and asexual reproduction in the origin and spread of strains causing fungal infectious diseases outbreaks. The necessity of sex and the ability of asexual fungi to initiate outbreaks are discussed. We propose a framework that relates the modes of reproduction to the origin and propagation of fungal disease outbreaks. Our analyses suggest that both sexual and asexual reproduction can play critical roles in the origin of outbreak strains and that the rapid spread of outbreak strains is often accomplished through asexual expansion.
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Affiliation(s)
- Eta Ebasi Ashu
- Department of Biology, McMaster University, 1280 Main St. W, Hamilton, ON L8S 4K1, Canada
| | - Jianping Xu
- Department of Biology, McMaster University, 1280 Main St. W, Hamilton, ON L8S 4K1, Canada.
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