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Hak H, Raanan H, Schwarz S, Sherman Y, Dinesh‐Kumar SP, Spiegelman Z. Activation of Tm-2 2 resistance is mediated by a conserved cysteine essential for tobacco mosaic virus movement. MOLECULAR PLANT PATHOLOGY 2023; 24:838-848. [PMID: 37086003 PMCID: PMC10346382 DOI: 10.1111/mpp.13318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 02/08/2023] [Accepted: 02/12/2023] [Indexed: 05/03/2023]
Abstract
The tomato Tm-22 gene was considered to be one of the most durable resistance genes in agriculture, protecting against viruses of the Tobamovirus genus, such as tomato mosaic virus (ToMV) and tobacco mosaic virus (TMV). However, an emerging tobamovirus, tomato brown rugose fruit virus (ToBRFV), has overcome Tm-22 , damaging tomato production worldwide. Tm-22 encodes a nucleotide-binding leucine-rich repeat (NLR) class immune receptor that recognizes its effector, the tobamovirus movement protein (MP). Previously, we found that ToBRFV MP (MPToBRFV ) enabled the virus to overcome Tm-22 -mediated resistance. Yet, it was unknown how Tm-22 remained durable against other tobamoviruses, such as TMV and ToMV, for over 60 years. Here, we show that a conserved cysteine (C68) in the MP of TMV (MPTMV ) plays a dual role in Tm-22 activation and viral movement. Substitution of MPToBRFV amino acid H67 with the corresponding amino acid in MPTMV (C68) activated Tm-22 -mediated resistance. However, replacement of C68 in TMV and ToMV disabled the infectivity of both viruses. Phylogenetic and structural prediction analysis revealed that C68 is conserved among all Solanaceae-infecting tobamoviruses except ToBRFV and localizes to a predicted jelly-roll fold common to various MPs. Cell-to-cell and subcellular movement analysis showed that C68 is required for the movement of TMV by regulating the MP interaction with the endoplasmic reticulum and targeting it to plasmodesmata. The dual role of C68 in viral movement and Tm-22 immune activation could explain how TMV was unable to overcome this resistance for such a long period.
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Affiliation(s)
- Hagit Hak
- Department of Plant Pathology and Weed Research, Agricultural Research OrganizationThe Volcani InstituteRishon LeZionIsrael
| | - Hagai Raanan
- Department of Plant Pathology and Weed Research, Agricultural Research OrganizationThe Volcani InstituteRishon LeZionIsrael
- Gilat Research CenterAgricultural Research OrganizationNegevIsrael
| | - Shahar Schwarz
- Department of Plant Pathology and Weed Research, Agricultural Research OrganizationThe Volcani InstituteRishon LeZionIsrael
| | - Yifat Sherman
- Department of Plant Pathology and Weed Research, Agricultural Research OrganizationThe Volcani InstituteRishon LeZionIsrael
- The Robert H. Smith Faculty of Agriculture, Food and EnvironmentThe Hebrew University of JerusalemRehovotIsrael
| | - Savithramma P. Dinesh‐Kumar
- Department of Plant Biology and Genome CenterCollege of Biological Sciences, University of CaliforniaDavisCaliforniaUSA
| | - Ziv Spiegelman
- Department of Plant Pathology and Weed Research, Agricultural Research OrganizationThe Volcani InstituteRishon LeZionIsrael
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Clin P, Grognard F, Andrivon D, Mailleret L, Hamelin FM. The proportion of resistant hosts in mixtures should be biased towards the resistance with the lowest breaking cost. PLoS Comput Biol 2023; 19:e1011146. [PMID: 37228168 DOI: 10.1371/journal.pcbi.1011146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 05/01/2023] [Indexed: 05/27/2023] Open
Abstract
Current agricultural practices facilitate emergence and spread of plant diseases through the wide use of monocultures. Host mixtures are a promising alternative for sustainable plant disease control. Their effectiveness can be partly explained by priming-induced cross-protection among plants. Priming occurs when plants are challenged with non-infective pathogen genotypes, resulting in increased resistance to subsequent infections by infective pathogen genotypes. We developed an epidemiological model to explore how mixing two distinct resistant varieties can reduce disease prevalence. We considered a pathogen population composed of three genotypes infecting either one or both varieties. We found that host mixtures should not contain an equal proportion of resistant plants, but a biased ratio (e.g. 80 : 20) to minimize disease prevalence. Counter-intuitively, the optimal ratio of resistant varieties should contain a lower proportion of the costliest resistance for the pathogen to break. This benefit is amplified by priming. This strategy also prevents the invasion of pathogens breaking all resistances.
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Affiliation(s)
- Pauline Clin
- Institut Agro, Univ Rennes, INRAE, IGEPP, Rennes, France
- Université Côte d'Azur, INRAE, CNRS, ISA, Sophia-Antipolis, France
| | - Frédéric Grognard
- Université Côte d'Azur, Inria, INRAE, CNRS, Sorbonne Université, Biocore, Sophia-Antipolis, France
| | | | - Ludovic Mailleret
- Université Côte d'Azur, INRAE, CNRS, ISA, Sophia-Antipolis, France
- Université Côte d'Azur, Inria, INRAE, CNRS, Sorbonne Université, Biocore, Sophia-Antipolis, France
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3
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Moreno‐Pérez MG, Bera S, McLeish M, Fraile A, García‐Arenal F. Reversion of a resistance-breaking mutation shows reversion costs and high virus diversity at necrotic local lesions. MOLECULAR PLANT PATHOLOGY 2023; 24:142-153. [PMID: 36435959 PMCID: PMC9831284 DOI: 10.1111/mpp.13281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 09/28/2022] [Accepted: 10/29/2022] [Indexed: 06/16/2023]
Abstract
An instance of host range evolution relevant to plant virus disease control is resistance breaking. Resistance breaking can be hindered by across-host fitness trade-offs generated by negative effects of resistance-breaking mutations on the virus fitness in susceptible hosts. Different mutations in pepper mild mottle virus (PMMoV) coat protein result in the breaking in pepper plants of the resistance determined by the L3 resistance allele. Of these, mutation M138N is widespread in PMMoV populations, despite associated fitness penalties in within-host multiplication and survival. The stability of mutation M138N was analysed by serial passaging in L3 resistant plants. Appearance on passaging of necrotic local lesions (NLL), indicating an effective L3 resistance, showed reversion to nonresistance-breaking phenotypes was common. Most revertant genotypes had the mutation N138K, which affects the properties of the virus particle, introducing a penalty of reversion. Hence, the costs of reversion may determine the evolution of resistance-breaking in addition to resistance-breaking costs. The genetic diversity of the virus population in NLL was much higher than in systemically infected tissues, and included mutations reported to break L3 resistance other than M138N. Infectivity assays on pepper genotypes with different L alleles showed high phenotypic diversity in respect to L alleles in NLL, including phenotypes not reported in nature. Thus, high diversity at NLL may potentiate the appearance of genotypes that enable the colonization of new host genotypes or species. Collectively, the results of this study contribute to better understanding the evolutionary dynamics of resistance breaking and host-range expansions.
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Affiliation(s)
- Manuel G. Moreno‐Pérez
- Centro de Biotecnología y Genómica de Plantas UPM‐INIA/CSICUniversidad Politécnica de MadridMadridSpain
- E.T.S.I. Agronómica, Alimentaria y de BiosistemasCampus de Montegancedo, UPMMadridSpain
| | - Sayanta Bera
- Centro de Biotecnología y Genómica de Plantas UPM‐INIA/CSICUniversidad Politécnica de MadridMadridSpain
- E.T.S.I. Agronómica, Alimentaria y de BiosistemasCampus de Montegancedo, UPMMadridSpain
| | - Michael McLeish
- Centro de Biotecnología y Genómica de Plantas UPM‐INIA/CSICUniversidad Politécnica de MadridMadridSpain
- E.T.S.I. Agronómica, Alimentaria y de BiosistemasCampus de Montegancedo, UPMMadridSpain
| | - Aurora Fraile
- Centro de Biotecnología y Genómica de Plantas UPM‐INIA/CSICUniversidad Politécnica de MadridMadridSpain
- E.T.S.I. Agronómica, Alimentaria y de BiosistemasCampus de Montegancedo, UPMMadridSpain
| | - Fernando García‐Arenal
- Centro de Biotecnología y Genómica de Plantas UPM‐INIA/CSICUniversidad Politécnica de MadridMadridSpain
- E.T.S.I. Agronómica, Alimentaria y de BiosistemasCampus de Montegancedo, UPMMadridSpain
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Plant Virus Adaptation to New Hosts: A Multi-scale Approach. Curr Top Microbiol Immunol 2023; 439:167-196. [PMID: 36592246 DOI: 10.1007/978-3-031-15640-3_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Viruses are studied at each level of biological complexity: from within-cells to ecosystems. The same basic evolutionary forces and principles operate at each level: mutation and recombination, selection, genetic drift, migration, and adaptive trade-offs. Great efforts have been put into understanding each level in great detail, hoping to predict the dynamics of viral population, prevent virus emergence, and manage their spread and virulence. Unfortunately, we are still far from this. To achieve these ambitious goals, we advocate for an integrative perspective of virus evolution. Focusing in plant viruses, we illustrate the pervasiveness of the above-mentioned principles. Beginning at the within-cell level, we describe replication modes, infection bottlenecks, and cellular contagion rates. Next, we move up to the colonization of distal tissues, discussing the fundamental role of random events. Then, we jump beyond the individual host and discuss the link between transmission mode and virulence. Finally, at the community level, we discuss properties of virus-plant infection networks. To close this review we propose the multilayer network theory, in which elements at different layers are connected and submit to their own dynamics that feed across layers, resulting in new emerging properties, as a way to integrate information from the different levels.
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Clin P, Grognard F, Andrivon D, Mailleret L, Hamelin FM. Host mixtures for plant disease control: Benefits from pathogen selection and immune priming. Evol Appl 2022; 15:967-975. [PMID: 35782013 PMCID: PMC9234633 DOI: 10.1111/eva.13386] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 03/28/2022] [Accepted: 04/05/2022] [Indexed: 11/29/2022] Open
Abstract
Multiline and cultivar mixtures are highly effective methods for agroecological plant disease control. Priming-induced cross protection, occurring when plants are challenged by avirulent pathogen genotypes and resulting in increased resistance to subsequent infection by virulent ones, is one critical key to their lasting performance against polymorphic pathogen populations. Strikingly, this mechanism was until recently absent from mathematical models aiming at designing optimal host mixtures. We developed an epidemiological model to explore the effect of host mixtures composed of variable numbers of single-resistance cultivars on the equilibrium prevalence of the disease caused by pathogen populations polymorphic for virulence complexity. This model shows that a relatively large amount of resistance genes must be deployed to achieve low disease prevalence, as pathogen competition in mixtures tends to select for intermediate virulence complexity. By contrast, priming significantly reduces the number of plant genotypes needed to drop disease prevalence below an acceptable threshold. Given the limited availability of resistance genes in cultivars, this mechanism of plant immunity should be assessed when designing host mixtures.
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Affiliation(s)
- Pauline Clin
- Institut Agro, INRAE, IGEPPUniv RennesRennesFrance
- INRAE, CNRS, ISAUniversité Côte d’AzurNiceFrance
| | - Frédéric Grognard
- Inria, INRAE, CNRS, Sorbonne Université, BiocoreUniversité Côte d’AzurNiceFrance
| | | | - Ludovic Mailleret
- INRAE, CNRS, ISAUniversité Côte d’AzurNiceFrance
- Inria, INRAE, CNRS, Sorbonne Université, BiocoreUniversité Côte d’AzurNiceFrance
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6
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Host Diversification May Split Epidemic Spread into Two Successive Fronts Advancing at Different Speeds. Bull Math Biol 2022; 84:68. [DOI: 10.1007/s11538-022-01023-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 04/13/2022] [Indexed: 11/02/2022]
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Bramham LE, Wang T, Higgins EE, Parkin IAP, Barker GC, Walsh JA. Characterization and Mapping of retr04, retr05 and retr06 Broad-Spectrum Resistances to Turnip Mosaic Virus in Brassica juncea, and the Development of Robust Methods for Utilizing Recalcitrant Genotyping Data. FRONTIERS IN PLANT SCIENCE 2022; 12:787354. [PMID: 35095961 PMCID: PMC8790578 DOI: 10.3389/fpls.2021.787354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/24/2021] [Indexed: 06/14/2023]
Abstract
Turnip mosaic virus (TuMV) induces disease in susceptible hosts, notably impacting cultivation of important crop species of the Brassica genus. Few effective plant viral disease management strategies exist with the majority of current approaches aiming to mitigate the virus indirectly through control of aphid vector species. Multiple sources of genetic resistance to TuMV have been identified previously, although the majority are strain-specific and have not been exploited commercially. Here, two Brassica juncea lines (TWBJ14 and TWBJ20) with resistance against important TuMV isolates (UK 1, vVIR24, CDN 1, and GBR 6) representing the most prevalent pathotypes of TuMV (1, 3, 4, and 4, respectively) and known to overcome other sources of resistance, have been identified and characterized. Genetic inheritance of both resistances was determined to be based on a recessive two-gene model. Using both single nucleotide polymorphism (SNP) array and genotyping by sequencing (GBS) methods, quantitative trait loci (QTL) analyses were performed using first backcross (BC1) genetic mapping populations segregating for TuMV resistance. Pairs of statistically significant TuMV resistance-associated QTLs with additive interactive effects were identified on chromosomes A03 and A06 for both TWBJ14 and TWBJ20 material. Complementation testing between these B. juncea lines indicated that one resistance-linked locus was shared. Following established resistance gene nomenclature for recessive TuMV resistance genes, these new resistance-associated loci have been termed retr04 (chromosome A06, TWBJ14, and TWBJ20), retr05 (A03, TWBJ14), and retr06 (A03, TWBJ20). Genotyping by sequencing data investigated in parallel to robust SNP array data was highly suboptimal, with informative data not established for key BC1 parental samples. This necessitated careful consideration and the development of new methods for processing compromised data. Using reductive screening of potential markers according to allelic variation and the recombination observed across BC1 samples genotyped, compromised GBS data was rendered functional with near-equivalent QTL outputs to the SNP array data. The reductive screening strategy employed here offers an alternative to methods relying upon imputation or artificial correction of genotypic data and may prove effective for similar biparental QTL mapping studies.
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Affiliation(s)
- Lawrence E. Bramham
- School of Life Sciences, University of Warwick, Wellesbourne Campus, Warwick, United Kingdom
| | - Tongtong Wang
- School of Life Sciences, University of Warwick, Wellesbourne Campus, Warwick, United Kingdom
| | | | | | - Guy C. Barker
- School of Life Sciences, University of Warwick, Wellesbourne Campus, Warwick, United Kingdom
| | - John A. Walsh
- School of Life Sciences, University of Warwick, Wellesbourne Campus, Warwick, United Kingdom
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Clin P, Grognard F, Mailleret L, Val F, Andrivon D, Hamelin FM. Taking Advantage of Pathogen Diversity and Immune Priming to Minimize Disease Prevalence in Host Mixtures: A Model. PHYTOPATHOLOGY 2021; 111:1219-1227. [PMID: 33297731 DOI: 10.1094/phyto-09-20-0429-r] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Host mixtures are a promising method for agroecological plant disease control. Plant immunity is key to the success of host mixtures against polymorphic pathogen populations. This immunity results from priming-induced cross-protection, whereby plants able to resist infection by specific pathogen genotypes become more resistant to other pathogen genotypes. Strikingly, this phenomenon was absent from mathematical models aiming at designing host mixtures. We developed a model to specifically explore how priming affects the coexistence of two pathogen genotypes in host mixtures composed of two host genotypes and how it affects disease prevalence. The main effect of priming is to reduce the coexistence region in the parameter space (due to the cross-protection) and to generate a singular mixture of resistant and susceptible hosts corresponding to the maximal reduction disease prevalence (in absence of priming, a resistant pure stand is optimal). The epidemiological advantage of host mixtures over a resistant pure stand thus appears as a direct consequence of immune priming. We also showed that there is indirect cross-protection between host genotypes in a mixture. Moreover, the optimal mix prevents the emergence of a resistance-breaking pathogen genotype. Our results highlight the importance of considering immune priming to design optimal and sustainable host mixtures.
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Affiliation(s)
- Pauline Clin
- IGEPP, INRAE, Institut Agro, Université Rennes, 35000 Rennes, France
- Université Côte d'Azur, INRAE, CNRS, ISA, France
| | - Frédéric Grognard
- Université Côte d'Azur, Inria, INRAE, CNRS, Sorbonne Université, Biocore, France
| | - Ludovic Mailleret
- Université Côte d'Azur, INRAE, CNRS, ISA, France
- Université Côte d'Azur, Inria, INRAE, CNRS, Sorbonne Université, Biocore, France
| | - Florence Val
- IGEPP, INRAE, Institut Agro, Université Rennes, 35000 Rennes, France
| | - Didier Andrivon
- IGEPP, INRAE, Institut Agro, Université Rennes, 35000 Rennes, France
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9
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Respiratory Burst Oxidase Homologs RBOHD and RBOHF as Key Modulating Components of Response in Turnip Mosaic Virus- Arabidopsis thaliana (L.) Heyhn System. Int J Mol Sci 2020; 21:ijms21228510. [PMID: 33198167 PMCID: PMC7696843 DOI: 10.3390/ijms21228510] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 11/07/2020] [Accepted: 11/10/2020] [Indexed: 12/11/2022] Open
Abstract
Turnip mosaic virus (TuMV) is one of the most important plant viruses worldwide. It has a very wide host range infecting at least 318 species in over 43 families, such as Brassicaceae, Fabaceae, Asteraceae, or Chenopodiaceae from dicotyledons. Plant NADPH oxidases, the respiratory burst oxidase homologues (RBOHs), are a major source of reactive oxygen species (ROS) during plant–microbe interactions. The functions of RBOHs in different plant–pathogen interactions have been analyzed using knockout mutants, but little focus has been given to plant–virus responses. Therefore, in this work we tested the response after mechanical inoculation with TuMV in ArabidopsisrbohD and rbohF transposon knockout mutants and analyzed ultrastructural changes after TuMV inoculation. The development of the TuMV infection cycle was promoted in rbohD plants, suggesting that RbohD plays a role in the Arabidopsis resistance response to TuMV. rbohF and rbohD/F mutants display less TuMV accumulation and a lack of virus cytoplasmic inclusions were observed; these observations suggest that RbohF promotes viral replication and increases susceptibility to TuMV. rbohD/F displayed a reduction in H2O2 but enhanced resistance similarly to rbohF. This dominant effect of the rbohF mutation could indicate that RbohF acts as a susceptibility factor. Induction of hydrogen peroxide by TuMV was partially compromised in rbohD mutants whereas it was almost completely abolished in rbohD/F, indicating that these oxidases are responsible for most of the ROS produced in this interaction. The pattern of in situ H2O2 deposition after infection of the more resistant rbohF and rbohD/F genotypes suggests a putative role of these species on systemic signal transport. The ultrastructural localization and quantification of pathogenesis-related protein 1 (PR1) indicate that ROS produced by these oxidases also influence PR1 distribution in the TuMV-A.thaliana pathosystem. Our results revealed the highest activation of PR1 in rbohD and Col-0. Thus, our findings indicate a correlation between PR1 accumulation and susceptibility to TuMV. The specific localization of PR1 in the most resistant genotypes after TuMV inoculation may indicate a connection of PR1 induction with susceptibility, which may be characteristic for this pathosystem. Our results clearly indicate the importance of NADPH oxidases RbohD and RbohF in the regulation of the TuMV infection cycle in Arabidopsis. These findings may help provide a better understanding of the mechanisms modulating A.thaliana–TuMV interactions.
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Lv H, Fang Z, Yang L, Zhang Y, Wang Y. An update on the arsenal: mining resistance genes for disease management of Brassica crops in the genomic era. HORTICULTURE RESEARCH 2020; 7:34. [PMID: 32194970 PMCID: PMC7072071 DOI: 10.1038/s41438-020-0257-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 01/12/2020] [Accepted: 01/15/2020] [Indexed: 05/18/2023]
Abstract
Brassica species include many economically important crops that provide nutrition and health-promoting substances to humans worldwide. However, as with all crops, their production is constantly threatened by emerging viral, bacterial, and fungal diseases, whose incidence has increased in recent years. Traditional methods of control are often costly, present limited effectiveness, and cause environmental damage; instead, the ideal approach is to mine and utilize the resistance genes of the Brassica crop hosts themselves. Fortunately, the development of genomics, molecular genetics, and biological techniques enables us to rapidly discover and apply resistance (R) genes. Herein, the R genes identified in Brassica crops are summarized, including their mapping and cloning, possible molecular mechanisms, and application in resistance breeding. Future perspectives concerning how to accurately discover additional R gene resources and efficiently utilize these genes in the genomic era are also discussed.
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Affiliation(s)
- Honghao Lv
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, 12# Zhongguancun South Street, Beijing, 100081 China
| | - Zhiyuan Fang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, 12# Zhongguancun South Street, Beijing, 100081 China
| | - Limei Yang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, 12# Zhongguancun South Street, Beijing, 100081 China
| | - Yangyong Zhang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, 12# Zhongguancun South Street, Beijing, 100081 China
| | - Yong Wang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, 12# Zhongguancun South Street, Beijing, 100081 China
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11
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Kim IH, Ju HK, Gong J, Han JY, Seo EY, Cho SW, Hu WX, Choi SR, Lim YP, Domier LL, Hammond J, Lim HS. A Turnip Mosaic Virus Determinant of Systemic Necrosis in Nicotiana benthamiana and a Novel Resistance-Breaking Determinant in Chinese Cabbage Identified from Chimeric Infectious Clones. PHYTOPATHOLOGY 2019; 109:1638-1647. [PMID: 31044662 DOI: 10.1094/phyto-08-18-0323-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Infectious clones of Korean turnip mosaic virus (TuMV) isolates KIH1 and HJY1 share 88.1% genomic nucleotides and 96.4% polyprotein amino acid identity, and they induce systemic necrosis or mild mosaic, respectively, in Nicotiana benthamiana. Chimeric constructs between these isolates exchanged the 5', central, and 3' domains of KIH1 (K) and HJY1 (H), where the order of the letters indicates the origin of these domains. KIH1 and chimeras KHH and KKH induced systemic necrosis, whereas HJY1 and chimeras HHK, HKK, and HKH induced mild symptoms, indicating the determinant of necrosis to be within the 5' 3.9 kb of KIH1; amino acid identities of the included P1, Helper component protease, P3, 6K1, and cylindrical inclusion N-terminal domain were 90.06, 98.91, 93.80, 100, and 100%, respectively. Expression of P1 or P3 from a potato virus X vector yielded symptom differences only between P3 of KIH1 and HJY1, implicating a role for P3 in necrosis in N. benthamiana. Chimera KKH infected Brassica rapa var. pekinensis 'Norang', which was resistant to both KIH1 and HJY1, indicating that two separate TuMV determinants are required to overcome the resistance. Ability of diverse TuMV isolates, chimeras, and recombinants to overcome resistance in breeding lines may allow identification of novel resistance genes.
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Affiliation(s)
- Ik-Hyun Kim
- Department of Applied Biology, Chungnam National University, Daejeon, South Korea
| | - Hye-Kyoung Ju
- Department of Applied Biology, Chungnam National University, Daejeon, South Korea
| | - Junsu Gong
- Department of Applied Biology, Chungnam National University, Daejeon, South Korea
| | - Jae-Yeong Han
- Department of Applied Biology, Chungnam National University, Daejeon, South Korea
| | - Eun-Young Seo
- Department of Applied Biology, Chungnam National University, Daejeon, South Korea
| | - Sang-Won Cho
- Department of Applied Biology, Chungnam National University, Daejeon, South Korea
| | - Wen-Xing Hu
- Department of Applied Biology, Chungnam National University, Daejeon, South Korea
| | - Su Ryun Choi
- Department of Horticulture, Chungnam National University, Daejeon, South Korea
| | - Yong Pyo Lim
- Department of Horticulture, Chungnam National University, Daejeon, South Korea
| | - Leslie L Domier
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, U.S.A
| | - John Hammond
- Floral and Nursery Plants Research Unit, U.S. National Arboretum, U.S. Department of Agriculture-Agriculture Research Service, Beltsville, MD, U.S.A
| | - Hyoun-Sub Lim
- Department of Applied Biology, Chungnam National University, Daejeon, South Korea
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12
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Lefeuvre P, Martin DP, Elena SF, Shepherd DN, Roumagnac P, Varsani A. Evolution and ecology of plant viruses. Nat Rev Microbiol 2019; 17:632-644. [PMID: 31312033 DOI: 10.1038/s41579-019-0232-3] [Citation(s) in RCA: 118] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2019] [Indexed: 02/07/2023]
Abstract
The discovery of the first non-cellular infectious agent, later determined to be tobacco mosaic virus, paved the way for the field of virology. In the ensuing decades, research focused on discovering and eliminating viral threats to plant and animal health. However, recent conceptual and methodological revolutions have made it clear that viruses are not merely agents of destruction but essential components of global ecosystems. As plants make up over 80% of the biomass on Earth, plant viruses likely have a larger impact on ecosystem stability and function than viruses of other kingdoms. Besides preventing overgrowth of genetically homogeneous plant populations such as crop plants, some plant viruses might also promote the adaptation of their hosts to changing environments. However, estimates of the extent and frequencies of such mutualistic interactions remain controversial. In this Review, we focus on the origins of plant viruses and the evolution of interactions between these viruses and both their hosts and transmission vectors. We also identify currently unknown aspects of plant virus ecology and evolution that are of practical importance and that should be resolvable in the near future through viral metagenomics.
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Affiliation(s)
| | - Darren P Martin
- Computational Biology Division, Department of Integrative Biomedical Sciences, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Santiago F Elena
- Instituto de Biología Integrativa de Sistemas (I2SysBio), CSIC-UV, Paterna, València, Spain.,The Santa Fe Institute, Santa Fe, NM, USA
| | | | - Philippe Roumagnac
- CIRAD, UMR BGPI, Montpellier, France.,BGPI, CIRAD, INRA, Montpellier SupAgro, University of Montpellier, Montpellier, France
| | - Arvind Varsani
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ, USA. .,Structural Biology Research Unit, Department of Integrative Biomedical Sciences, University of Cape Town, Cape Town, South Africa.
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13
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Charon J, Barra A, Walter J, Millot P, Hébrard E, Moury B, Michon T. First Experimental Assessment of Protein Intrinsic Disorder Involvement in an RNA Virus Natural Adaptive Process. Mol Biol Evol 2019; 35:38-49. [PMID: 29029259 PMCID: PMC5850501 DOI: 10.1093/molbev/msx249] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Intrinsic disorder (ID) in proteins is defined as a lack of stable structure in physiological conditions. Intrinsically disordered regions (IDRs) are highly abundant in some RNA virus proteomes. Low topological constraints exerted on IDRs are expected to buffer the effect of numerous deleterious mutations and could be related to the remarkable adaptive potential of RNA viruses to overcome resistance of their host. To experimentally test this hypothesis in a natural pathosystem, a set of four variants of Potato virus Y (PVY; Potyvirus genus) containing various ID degrees in the Viral genome-linked (VPg) protein, a key determinant of potyvirus adaptation, was designed. To estimate the ID contribution to the VPg-based PVY adaptation, the adaptive ability of the four PVY variants was monitored in the pepper host (Capsicum annuum) carrying a recessive resistance gene. Intriguingly, the two mutants with the highest ID content displayed a significantly higher ability to restore infection in the resistant host, whereas the less intrinsically disordered mutant was unable to restore infection. The role of ID on virus adaptation may be due either to a larger exploration of evolutionary pathways or the minimization of fitness penalty caused by resistance-breaking mutations. This pioneering study strongly suggests the positive impact of ID in an RNA virus adaptive capacity.
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Affiliation(s)
- Justine Charon
- UMR Biologie du Fruit et Pathologie, INRA, Université de Bordeaux, Villenave d'Ornon, France.,CNRS 5320, INSERM U1212, Pessac, France
| | - Amandine Barra
- UMR Biologie du Fruit et Pathologie, INRA, Université de Bordeaux, Villenave d'Ornon, France
| | - Jocelyne Walter
- UMR Biologie du Fruit et Pathologie, INRA, Université de Bordeaux, Villenave d'Ornon, France
| | | | - Eugénie Hébrard
- UMR Interactions Plantes-Microorganismes-Environnement, IRD, CIRAD, Université de Montpellier, Montpellier, France
| | | | - Thierry Michon
- UMR Biologie du Fruit et Pathologie, INRA, Université de Bordeaux, Villenave d'Ornon, France
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14
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Chisholm PJ, Busch JW, Crowder DW. Effects of life history and ecology on virus evolutionary potential. Virus Res 2019; 265:1-9. [PMID: 30831177 DOI: 10.1016/j.virusres.2019.02.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/27/2019] [Accepted: 02/28/2019] [Indexed: 11/28/2022]
Abstract
The life history traits of viruses pose many consequences for viral population structure. In turn, population structure may influence the evolutionary trajectory of a virus. Here we review factors that affect the evolutionary potential of viruses, including rates of mutation and recombination, bottlenecks, selection pressure, and ecological factors such as the requirement for hosts and vectors. Mutation, while supplying a pool of raw genetic material, also results in the generation of numerous unfit mutants. The infection of multiple host species may expand a virus' ecological niche, although it may come at a cost to genetic diversity. Vector-borne viruses often experience a diminished frequency of positive selection and exhibit little diversity, and resistance against vector-borne viruses may thus be more durable than against non-vectored viruses. Evidence indicates that adaptation to a vector is more evolutionarily difficult than adaptation to a host. Overall, a better understanding of how various factors influence viral dynamics in both plant and animal pathosystems will lead to more effective anti-viral treatments and countermeasures.
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Affiliation(s)
- Paul J Chisholm
- Department of Entomology, Washington State University, 166 FSHN Building, Pullman, WA, 99164, USA.
| | - Jeremiah W Busch
- School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA, 99164, USA.
| | - David W Crowder
- Department of Entomology, Washington State University, 166 FSHN Building, Pullman, WA, 99164, USA.
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15
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Mwangi JM, Niere B, Finckh MR, Krüssel S, Kiewnick S. Reproduction and life history traits of a resistance breaking Globodera pallida population. J Nematol 2019. [DOI: 10.21307/jofnem-2019-079] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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16
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Role of the Genetic Background in Resistance to Plant Viruses. Int J Mol Sci 2018; 19:ijms19102856. [PMID: 30241370 PMCID: PMC6213453 DOI: 10.3390/ijms19102856] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 09/10/2018] [Accepted: 09/11/2018] [Indexed: 01/03/2023] Open
Abstract
In view of major economic problems caused by viruses, the development of genetically resistant crops is critical for breeders but remains limited by the evolution of resistance-breaking virus mutants. During the plant breeding process, the introgression of traits from Crop Wild Relatives results in a dramatic change of the genetic background that can alter the resistance efficiency or durability. Here, we conducted a meta-analysis on 19 Quantitative Trait Locus (QTL) studies of resistance to viruses in plants. Frequent epistatic effects between resistance genes indicate that a large part of the resistance phenotype, conferred by a given QTL, depends on the genetic background. We next reviewed the different resistance mechanisms in plants to survey at which stage the genetic background could impact resistance or durability. We propose that the genetic background may impair effector-triggered dominant resistances at several stages by tinkering the NB-LRR (Nucleotide Binding-Leucine-Rich Repeats) response pathway. In contrast, effects on recessive resistances by loss-of-susceptibility-such as eIF4E-based resistances-are more likely to rely on gene redundancy among the multigene family of host susceptibility factors. Finally, we show how the genetic background is likely to shape the evolution of resistance-breaking isolates and propose how to take this into account in order to breed plants with increased resistance durability to viruses.
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17
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McLeish MJ, Fraile A, García-Arenal F. Ecological Complexity in Plant Virus Host Range Evolution. Adv Virus Res 2018; 101:293-339. [PMID: 29908592 DOI: 10.1016/bs.aivir.2018.02.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The host range of a plant virus is the number of species in which it can reproduce. Most studies of plant virus host range evolution have focused on the genetics of host-pathogen interactions. However, the distribution and abundance of plant viruses and their hosts do not always overlap, and these spatial and temporal discontinuities in plant virus-host interactions can result in various ecological processes that shape host range evolution. Recent work shows that the distributions of pathogenic and resistant genotypes, vectors, and other resources supporting transmission vary widely in the environment, producing both expected and unanticipated patterns. The distributions of all of these factors are influenced further by competitive effects, natural enemies, anthropogenic disturbance, the abiotic environment, and herbivory to mention some. We suggest the need for further development of approaches that (i) explicitly consider resource use and the abiotic and biotic factors that affect the strategies by which viruses exploit resources; and (ii) are sensitive across scales. Host range and habitat specificity will largely determine which phyla are most likely to be new hosts, but predicting which host and when it is likely to be infected is enormously challenging because it is unclear how environmental heterogeneity affects the interactions of viruses and hosts.
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Affiliation(s)
- Michael J McLeish
- Centro de Biotecnología y Genómica de Plantas UPM-INIA, and E.T.S.I. Agrícola, Alimentaria y de Biosistemas, Campus de Montegancedo, Universidad Politécnica de Madrid, Madrid, Spain
| | - Aurora Fraile
- Centro de Biotecnología y Genómica de Plantas UPM-INIA, and E.T.S.I. Agrícola, Alimentaria y de Biosistemas, Campus de Montegancedo, Universidad Politécnica de Madrid, Madrid, Spain
| | - Fernando García-Arenal
- Centro de Biotecnología y Genómica de Plantas UPM-INIA, and E.T.S.I. Agrícola, Alimentaria y de Biosistemas, Campus de Montegancedo, Universidad Politécnica de Madrid, Madrid, Spain.
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18
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Cui X, Lu L, Wang Y, Yuan X, Chen X. The interaction of soybean reticulon homology domain protein (GmRHP) with Soybean mosaic virus encoded P3 contributes to the viral infection. Biochem Biophys Res Commun 2018; 495:2105-2110. [PMID: 29229386 DOI: 10.1016/j.bbrc.2017.12.043] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 12/07/2017] [Indexed: 10/18/2022]
Abstract
Soybean mosaic virus (SMV), a member of the Potyvirus genus, is a prevalent and devastating viral pathogen in soybean-growing regions worldwide. Potyvirus replication occurs in the 6K2-induced viral replication complex at endoplasmic reticulum exit sites. Potyvirus-encoded P3 is also associated with the endoplasmic reticulum and is as an essential component of the viral replication complex, playing a key role in viral replication. This study provides evidence that the soybean (Glycine max) reticulon homology domain protein (designated as GmRHP) interacts with SMV-P3 by using a two-hybrid yeast system to screen a soybean cDNA library. A bimolecular fluorescence complementation assay further confirmed the interaction, which occurred on the cytomembrane, endoplasmic reticulum and cytoskeleton in Nicotiana benthamiana cells. The transient expression of GmRHP can promote the coupling of Turnip mosaic virus replication and cell-to-cell movement in N. benthamiana. The interaction between the membrane protein SMV-P3 and GmRHP may contribute to the potyvirus infection, and GmRHP may be an essential host factor for P3's involvement in potyvirus replication.
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Affiliation(s)
- Xiaoyan Cui
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing, Jiangsu, 210014, PR China
| | - Lu Lu
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing, Jiangsu, 210014, PR China
| | - Ying Wang
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing, Jiangsu, 210014, PR China; Department of Horticulture, School of Horticulture and Plant Protection, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, PR China
| | - Xingxing Yuan
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing, Jiangsu, 210014, PR China
| | - Xin Chen
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing, Jiangsu, 210014, PR China.
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19
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Longue RDS, Traore VSE, Zinga I, Asante MD, Bouda Z, Neya JB, Barro N, Traore O. Pathogenicity of rice yellow mottle virus and screening of rice accessions from the Central African Republic. Virol J 2018; 15:6. [PMID: 29310664 PMCID: PMC5759187 DOI: 10.1186/s12985-017-0912-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 12/18/2017] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Rice yellow mottle virus (RYMV) of the genus Sobemovirus is the most important viral pathogen of rice causing more damage to rice crop in Sub Saharan Africa. The aim of this study was to conduct pathogenic characterization of RYMV isolates from the Central African Republic (CAR) and to screen commonly cultivated rice accessions in the country for resistance/tolerance to the virus. METHODS The pathogenicity of RYMV isolates was studied by mechanical inoculation with comparison to differential rice lines highly resistant to RYMV available at the Institute of Environment and Agricultural Research (INERA) in Burkina Faso. To screen commonly cultivated rice accessions in CAR, characterized RYMV isolates from the country were used as inoculum sources. Resistant breaking (RB) isolates were used to prepare RB-inoculum, whereas non-resistant breaking isolates (nRB) were used for nRB-inoculum. RESULTS Overall 102 isolates used in this study, 29.4% were able to overcome the high resistance genes in the rice cultivars Gigante and Tog7291. All isolates were distributed within three distinct pathogenic profiles. The first profile constituted of 6.9% of the isolates was able to break down the resistance in rice cultivar Gigante only. The second pathogenic profile made of 19.6% of isolates was able to infect Tog7291 only. The third profile, 2.9% of isolates overcame simultaneously resistance genes in both rice cultivars Gigante and Tog7291. Out of isolates able to break down the resistance gene in cultivar Gigante, a single isolate was found to be non-infectious to the susceptible control IR64. Data from screening showed that all accessions were susceptible to RYMV, although IRAT213 was found to be partially resistant to both nRB-inoculum and RB-inoculum. CONCLUSION The present study can be considered as the first in the Central African Republic, it gives a caution on the high risk of RYMV damage to rice production in the country. Beside, skills of pathogenic profiles of RYMV isolates will contribute to better disease management.
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Affiliation(s)
- Regis Dimitri Sokpe Longue
- Laboratory of Biological and Agronomic Sciences for Development (LaSBAD), Life Science Department, University of Bangui, BP 908 Bangui, Central African Republic
- Institute of Environment and Agricultural Research (INERA), Ouagadougou, 01 BP 476 Burkina Faso
| | | | - Innocent Zinga
- Laboratory of Biological and Agronomic Sciences for Development (LaSBAD), Life Science Department, University of Bangui, BP 908 Bangui, Central African Republic
| | - Maxwell Darko Asante
- Concil for Scientific and Industrial Research –Crop Research Institute, CSIR-CRI, P.O. Box 3785, Kumasi, Ghana
| | - Zakaria Bouda
- Institute of Environment and Agricultural Research (INERA), Ouagadougou, 01 BP 476 Burkina Faso
| | - James Bouma Neya
- Institute of Environment and Agricultural Research (INERA), Ouagadougou, 01 BP 476 Burkina Faso
| | - Nicolas Barro
- Department of Biochemistry and Microbiology, University of Ouagadougou I-Professor Joseph Ki-Zerbo, Ouagadougou, Burkina Faso
| | - Oumar Traore
- Institute of Environment and Agricultural Research (INERA), Ouagadougou, 01 BP 476 Burkina Faso
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20
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Bera S, Moreno-Pérez MG, García-Figuera S, Pagán I, Fraile A, Pacios LF, García-Arenal F. Pleiotropic Effects of Resistance-Breaking Mutations on Particle Stability Provide Insight into Life History Evolution of a Plant RNA Virus. J Virol 2017; 91:e00435-17. [PMID: 28679755 PMCID: PMC5571237 DOI: 10.1128/jvi.00435-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 06/27/2017] [Indexed: 11/20/2022] Open
Abstract
In gene-for-gene host-virus interactions, virus evolution to infect and multiply in previously resistant host genotypes, i.e., resistance breaking, is a case of host range expansion, which is predicted to be associated with fitness penalties. Negative effects of resistance-breaking mutations on within-host virus multiplication have been documented for several plant viruses. However, understanding virus evolution requires analyses of potential trade-offs between different fitness components. Here we analyzed whether coat protein (CP) mutations in Pepper mild mottle virus that break L-gene resistance in pepper affect particle stability and, thus, survival in the environment. For this purpose, CP mutations determining the overcoming of L 3 and L 4 resistance alleles were introduced in biologically active cDNA clones. The kinetics of the in vitro disassembly of parental and mutant particles were compared under different conditions. Resistance-breaking mutations variously affected particle stability. Structural analyses identified the number and type of axial and side interactions of adjacent CP subunits in virions, which explained differences in particle stability and contribute to understanding of tobamovirus disassembly. Resistance-breaking mutations also affected virus multiplication and virulence in the susceptible host, as well as infectivity. The sense and magnitude of the effects of resistance-breaking mutations on particle stability, multiplication, virulence, or infectivity depended on the specific mutation rather than on the ability to overcome the different resistance alleles, and effects on different traits were not correlated. Thus, the results do not provide evidence of links or trade-offs between particle stability, i.e., survival, and other components of virus fitness or virulence.IMPORTANCE The effect of survival on virus evolution remains underexplored, despite the fact that life history trade-offs may constrain virus evolution. We approached this topic by analyzing whether breaking of L-gene resistance in pepper by Pepper mild mottle virus, determined by coat protein (CP) mutations, is associated with reduced particle stability and survival. Resistance-breaking mutations affected particle stability by altering the interactions between CP subunits. However, the sense and magnitude of these effects were unrelated to the capacity to overcome different resistance alleles. Thus, resistance breaking was not traded with survival. Resistance-breaking mutations also affected virus fitness within the infected host, virulence, and infectivity in a mutation-specific manner. Comparison of the effects of CP mutations on these various traits indicates that there are neither trade-offs nor positive links between survival and other life history traits. These results demonstrate that trade-offs between life history traits may not be a general constraint in virus evolution.
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Affiliation(s)
- Sayanta Bera
- Centro de Biotecnología y Genómica de Plantas and Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
| | - Manuel G Moreno-Pérez
- Centro de Biotecnología y Genómica de Plantas and Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
| | - Sara García-Figuera
- Centro de Biotecnología y Genómica de Plantas and Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
| | - Israel Pagán
- Centro de Biotecnología y Genómica de Plantas and Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
| | - Aurora Fraile
- Centro de Biotecnología y Genómica de Plantas and Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
| | - Luis F Pacios
- Centro de Biotecnología y Genómica de Plantas and Escuela Técnica Superior de Ingenieros de Montes, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
| | - Fernando García-Arenal
- Centro de Biotecnología y Genómica de Plantas and Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
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21
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Pinel-Galzi A, Dubreuil-Tranchant C, Hébrard E, Mariac C, Ghesquière A, Albar L. Mutations in Rice yellow mottle virus Polyprotein P2a Involved in RYMV2 Gene Resistance Breakdown. FRONTIERS IN PLANT SCIENCE 2016; 7:1779. [PMID: 27965688 PMCID: PMC5125353 DOI: 10.3389/fpls.2016.01779] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 11/11/2016] [Indexed: 05/09/2023]
Abstract
Rice yellow mottle virus (RYMV) is one of the major diseases of rice in Africa. The high resistance of the Oryza glaberrima Tog7291 accession involves a null allele of the RYMV2 gene, whose ortholog in Arabidopsis, CPR5, is a transmembrane nucleoporin involved in effector-triggered immunity. To optimize field deployment of the RYMV2 gene and improve its durability, which is often a weak point in varietal resistance, we analyzed its efficiency toward RYMV isolates representing the genetic diversity of the virus and the molecular basis of resistance breakdown. Tog7291 resistance efficiency was highly variable depending on the isolate used, with infection rates ranging from 0 to 98% of plants. Back-inoculation experiments indicated that infection cases were not due to an incomplete resistance phenotype but to the emergence of resistance-breaking (RB) variants. Interestingly, the capacity of the virus to overcome Tog7291 resistance is associated with a polymorphism at amino-acid 49 of the VPg protein which also affects capacity to overcome the previously studied RYMV1 resistance gene. This polymorphism appeared to be a main determinant of the emergence of RB variants. It acts independently of the resistance gene and rather reflects inter-species adaptation with potential consequences for the durability of resistance. RB mutations were identified by full-length or partial sequencing of the RYMV genome in infected Tog7291 plants and were validated by directed mutagenesis of an infectious viral clone. We found that Tog7291 resistance breakdown involved mutations in the putative membrane anchor domain of the polyprotein P2a. Although the precise effect of these mutations on rice/RYMV interaction is still unknown, our results offer a new perspective for the understanding of RYMV2 mediated resistance mechanisms. Interestingly, in the susceptible IR64 variety, RB variants showed low infectivity and frequent reversion to the wild-type genotype, suggesting that Tog7291 resistance breakdown is associated with a major loss of viral fitness in normally susceptible O. sativa varieties. Despite the high frequency of resistance breakdown in controlled conditions, this loss of fitness is an encouraging element with regards to RYMV2 resistance durability.
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Affiliation(s)
- Agnès Pinel-Galzi
- Interactions Plantes Microorganismes Environnement, Institut de Recherche pour le Développement – Centre de Coopération Internationale en Recherche Agronomique pour le Développement – Université de MontpellierMontpellier, France
| | - Christine Dubreuil-Tranchant
- Plant Diversity Adaptation and Development Research Unit, Institut de Recherche pour le Développement – Université de MontpellierMontpellier, France
| | - Eugénie Hébrard
- Interactions Plantes Microorganismes Environnement, Institut de Recherche pour le Développement – Centre de Coopération Internationale en Recherche Agronomique pour le Développement – Université de MontpellierMontpellier, France
| | - Cédric Mariac
- Plant Diversity Adaptation and Development Research Unit, Institut de Recherche pour le Développement – Université de MontpellierMontpellier, France
| | - Alain Ghesquière
- Plant Diversity Adaptation and Development Research Unit, Institut de Recherche pour le Développement – Université de MontpellierMontpellier, France
| | - Laurence Albar
- Plant Diversity Adaptation and Development Research Unit, Institut de Recherche pour le Développement – Université de MontpellierMontpellier, France
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Moreno-Pérez MG, García-Luque I, Fraile A, García-Arenal F. Mutations That Determine Resistance Breaking in a Plant RNA Virus Have Pleiotropic Effects on Its Fitness That Depend on the Host Environment and on the Type, Single or Mixed, of Infection. J Virol 2016; 90:9128-37. [PMID: 27489266 PMCID: PMC5044817 DOI: 10.1128/jvi.00737-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 07/25/2016] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED Overcoming host resistance in gene-for-gene host-virus interactions is an important instance of host range expansion, which can be hindered by across-host fitness trade-offs. Trade-offs are generated by negative effects of host range mutations on the virus fitness in the original host, i.e., by antagonistic pleiotropy. It has been reported that different mutations in Pepper mild mottle virus (PMMoV) coat protein result in overcoming L-gene resistance in pepper. To analyze if resistance-breaking mutations in PMMoV result in antagonistic pleiotropy, all reported mutations determining the overcoming of L(3) and L(4) alleles were introduced in biologically active cDNA clones. Then, the parental and mutant virus genotypes were assayed in susceptible pepper genotypes with an L(+), L(1), or L(2) allele, in single and in mixed infections. Resistance-breaking mutations had pleiotropic effects on the virus fitness that, according to the specific mutation, the host genotype, and the type of infection, single or mixed with other virus genotypes, were antagonistic or positive. Thus, resistance-breaking mutations can generate fitness trade-offs both across hosts and across types of infection, and the frequency of host range mutants will depend on the genetic structure of the host population and on the frequency of mixed infections by different virus genotypes. Also, resistance-breaking mutations variously affected virulence, which may further influence the evolution of host range expansion. IMPORTANCE A major cause of virus emergence is host range expansion, which may be hindered by across-host fitness trade-offs caused by negative pleiotropy of host range mutations. An important instance of host range expansion is overcoming host resistance in gene-for-gene plant-virus interactions. We analyze here if mutations in the coat protein of Pepper mild mottle virus determining L-gene resistance-breaking in pepper have associated fitness penalties in susceptible host genotypes. Results show that pleiotropic effects of resistance-breaking mutations on virus fitness depend on the specific mutation, the susceptible host genotype, and the type of infection, single or mixed, with other virus genotypes. Accordingly, resistance-breaking mutations can have negative, positive, or no pleiotropic effects on virus fitness. These results underscore the complexity of host range expansion evolution and, specifically, the difficulty of predicting the overcoming of resistance factors in crops.
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Affiliation(s)
- Manuel G Moreno-Pérez
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA) and E.T.S.I. Agrónomos, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
| | | | - Aurora Fraile
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA) and E.T.S.I. Agrónomos, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
| | - Fernando García-Arenal
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA) and E.T.S.I. Agrónomos, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
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23
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Elena SF. Local adaptation of plant viruses: lessons from experimental evolution. Mol Ecol 2016; 26:1711-1719. [PMID: 27612225 DOI: 10.1111/mec.13836] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 08/26/2016] [Accepted: 08/30/2016] [Indexed: 02/06/2023]
Abstract
For multihost pathogens, adaptation to multiple hosts has important implications for both applied and basic research. At the applied level, it is one of the main factors determining the probability and severity of emerging disease outbreaks. At the basic level, it is thought to be a key mechanism for the maintenance of genetic diversity both in host and pathogen species. In recent years, a number of evolution experiments have assessed the fate of plant virus populations replicating within and adapting to one single or to multiple hosts species. A first group of these experiments tackled the existence of trade-offs in fitness and virulence for viruses evolving either within a single hosts species or alternating between two different host species. A second set of experiments explored the role of genetic variability in susceptibility and resistance to infection among individuals from the same host species in the extent of virus local adaptation and of virulence. In general, when a single host species or genotype is available, these experiments show that local adaptation takes place, often but not always associated with a fitness trade-off. However, alternating between different host species or infecting resistant host genotypes may select for generalist viruses that experience no fitness cost. Therefore, the expected cost of generalism, arising from antagonistic pleiotropy and other genetic mechanisms generating fitness trade-offs between hosts, could not be generalized and strongly depend on the characteristics of each particular pathosystem. At the genomic level, these studies show pervasive convergent molecular evolution, suggesting that the number of accessible molecular pathways leading to adaptation to novel hosts is limited.
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Affiliation(s)
- Santiago F Elena
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, Valencia, 46022, Spain.,Instituto de Biología Integrativa y de Sistemas, Consejo Superior de Investigaciones Científicas-Universitat de València, Valencia, 46980, Spain.,The Santa Fe Institute, Santa Fe, NM, 87501, USA
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Wang Y, Hajimorad MR. Gain of virulence by Soybean mosaic virus on Rsv4-genotype soybeans is associated with a relative fitness loss in a susceptible host. MOLECULAR PLANT PATHOLOGY 2016; 17:1154-9. [PMID: 26662495 PMCID: PMC6638382 DOI: 10.1111/mpp.12354] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
'Gene-for-gene' theory predicts that gain of virulence by an avirulent pathogen on plants expressing resistance (R) genes is associated with fitness loss in susceptible hosts. However, the validity of this prediction has been studied in only a few plant viral pathosystems. In this study, the Soybean mosaic virus (SMV)-Rsv4 pathosystem was exploited to test this prediction. In Rsv4-genotype soybeans, P3 of avirulent SMV strains provokes an as yet uncharacterized resistance mechanism that restricts the invading virus to the inoculated leaves. A single amino acid substitution in P3 functionally converts an avirulent to a virulent strain, suggesting that the genetic composition of P3 plays a crucial role in virulence on Rsv4-genotype soybeans. In this study, we examined the impact of gain of virulence mutation(s) on the fitness of virulent variants derived from three avirulent SMV strains in a soybean genotype lacking the Rsv4 gene. Our data demonstrate that gain of virulence mutation(s) by all avirulent viruses on Rsv4-genotype soybean is associated with a relative fitness loss in a susceptible host. The implications of this finding on the durable deployment of the Rsv4 gene in soybean are discussed.
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Affiliation(s)
- Y Wang
- Department of Entomology and Plant Pathology, The University of Tennessee, Knoxville, TN, 37996, USA
| | - M R Hajimorad
- Department of Entomology and Plant Pathology, The University of Tennessee, Knoxville, TN, 37996, USA
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Atsumi G, Suzuki H, Miyashita Y, Choi SH, Hisa Y, Rihei S, Shimada R, Jeon EJ, Abe J, Nakahara KS, Uyeda I. P3N-PIPO, a Frameshift Product from the P3 Gene, Pleiotropically Determines the Virulence of Clover Yellow Vein Virus in both Resistant and Susceptible Peas. J Virol 2016; 90:7388-7404. [PMID: 27279605 PMCID: PMC4984661 DOI: 10.1128/jvi.00190-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 05/25/2016] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED Peas carrying the cyv1 recessive resistance gene are resistant to clover yellow vein virus (ClYVV) isolates No.30 (Cl-No.30) and 90-1 (Cl-90-1) but can be infected by a derivative of Cl-90-1 (Cl-90-1 Br2). The main determinant for the breaking of cyv1 resistance by Cl-90-1 Br2 is P3N-PIPO produced from the P3 gene via transcriptional slippage, and the higher level of P3N-PIPO produced by Cl-90-1 Br2 than by Cl-No.30 contributes to the breaking of resistance. Here we show that P3N-PIPO is also a major virulence determinant in susceptible peas that possess another resistance gene, Cyn1, which does not inhibit systemic infection with ClYVV but causes hypersensitive reaction-like lethal systemic cell death. We previously assumed that the susceptible pea cultivar PI 226564 has a weak allele of Cyn1 Cl-No.30 did not induce cell death, but Cl-90-1 Br2 killed the plants. Our results suggest that P3N-PIPO is recognized by Cyn1 and induces cell death. Unexpectedly, heterologously strongly expressed P3N-PIPO of Cl-No.30 appears to be recognized by Cyn1 in PI 226564. The level of P3N-PIPO accumulation from the P3 gene of Cl-No.30 was significantly lower than that of Cl-90-1 Br2 in a Nicotiana benthamiana transient assay. Therefore, Cyn1-mediated cell death also appears to be determined by the level of P3N-PIPO. The more efficiently a ClYVV isolate broke cyv1 resistance, the more it induced cell death systemically (resulting in a loss of the environment for virus accumulation) in susceptible peas carrying Cyn1, suggesting that antagonistic pleiotropy of P3N-PIPO controls the resistance breaking of ClYVV. IMPORTANCE Control of plant viral disease has relied on the use of resistant cultivars; however, emerging mutant viruses have broken many types of resistance. Recently, we revealed that Cl-90-1 Br2 breaks the recessive resistance conferred by cyv1, mainly by accumulating a higher level of P3N-PIPO than that of the nonbreaking isolate Cl-No.30. Here we show that a susceptible pea line recognized the increased amount of P3N-PIPO produced by Cl-90-1 Br2 and activated the salicylic acid-mediated defense pathway, inducing lethal systemic cell death. We found a gradation of virulence among ClYVV isolates in a cyv1-carrying pea line and two susceptible pea lines. This study suggests a trade-off between breaking of recessive resistance (cyv1) and host viability; the latter is presumably regulated by the dominant Cyn1 gene, which may impose evolutionary constraints upon P3N-PIPO for overcoming resistance. We propose a working model of the host strategy to sustain the durability of resistance and control fast-evolving viruses.
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Affiliation(s)
- Go Atsumi
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
- National Institute of Advanced Industrial Science and Technology, Sapporo, Hokkaido, Japan
| | - Haruka Suzuki
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Yuri Miyashita
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Sun Hee Choi
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Yusuke Hisa
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Shunsuke Rihei
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Ryoko Shimada
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Eun Jin Jeon
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Junya Abe
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kenji S Nakahara
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Ichiro Uyeda
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
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Fabre F, Rousseau E, Mailleret L, Moury B. Epidemiological and evolutionary management of plant resistance: optimizing the deployment of cultivar mixtures in time and space in agricultural landscapes. Evol Appl 2015; 8:919-32. [PMID: 26640518 PMCID: PMC4662345 DOI: 10.1111/eva.12304] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 08/05/2015] [Indexed: 12/11/2022] Open
Abstract
The management of genes conferring resistance to plant–pathogens should make it possible to control epidemics (epidemiological perspective) and preserve resistance durability (evolutionary perspective). Resistant and susceptible cultivars must be strategically associated according to the principles of cultivar mixture (within a season) and rotation (between seasons). We explored these questions by modeling the evolutionary and epidemiological processes shaping the dynamics of a pathogen population in a landscape composed of a seasonal cultivated compartment and a reservoir compartment hosting pathogen year-round. Optimal deployment strategies depended mostly on the molecular basis of plant–pathogen interactions and on the agro-ecological context before resistance deployment, particularly epidemic intensity and landscape connectivity. Mixtures were much more efficient in landscapes in which between-field infections and infections originating from the reservoir were more prevalent than within-field infections. Resistance genes requiring two mutations of the pathogen avirulence gene to be broken down, rather than one, were particularly useful when infections from the reservoir predominated. Combining mixture and rotation principles were better than the use of the same mixture each season as (i) they controlled epidemics more effectively in situations in which within-field infections or infections from the reservoir were frequent and (ii) they fulfilled the epidemiological and evolutionary perspectives.
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Affiliation(s)
- Frédéric Fabre
- UMR 1065 Unité Santé et Agroécologie du Vignoble, INRA Villenave d'Ornon Cedex, France
| | - Elsa Rousseau
- Biocore Team, INRIA Sophia Antipolis, France ; UMR 1355 Institut Sophia Agrobiotech, INRA Sophia Antipolis, France ; UMR 7254 Institut Sophia Agrobiotech, Université Nice Sophia Antipolis Sophia Antipolis, France ; UMR 7254 Institut Sophia Agrobiotech, CNRS Sophia Antipolis, France ; UR 407 Pathologie Végétale, INRA Montfavet, France
| | - Ludovic Mailleret
- Biocore Team, INRIA Sophia Antipolis, France ; UMR 1355 Institut Sophia Agrobiotech, INRA Sophia Antipolis, France ; UMR 7254 Institut Sophia Agrobiotech, Université Nice Sophia Antipolis Sophia Antipolis, France ; UMR 7254 Institut Sophia Agrobiotech, CNRS Sophia Antipolis, France
| | - Benoît Moury
- UR 407 Pathologie Végétale, INRA Montfavet, France
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Zhan J, Thrall PH, Papaïx J, Xie L, Burdon JJ. Playing on a pathogen's weakness: using evolution to guide sustainable plant disease control strategies. ANNUAL REVIEW OF PHYTOPATHOLOGY 2015; 53:19-43. [PMID: 25938275 DOI: 10.1146/annurev-phyto-080614-120040] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Wild plants and their associated pathogens are involved in ongoing interactions over millennia that have been modified by coevolutionary processes to limit the spatial extent and temporal duration of disease epidemics. These interactions are disrupted by modern agricultural practices and social activities, such as intensified monoculture using superior varieties and international trading of agricultural commodities. These activities, when supplemented with high resource inputs and the broad application of agrochemicals, create conditions uniquely conducive to widespread plant disease epidemics and rapid pathogen evolution. To be effective and durable, sustainable disease management requires a significant shift in emphasis to overtly include ecoevolutionary principles in the design of adaptive management programs aimed at minimizing the evolutionary potential of plant pathogens by reducing their genetic variation, stabilizing their evolutionary dynamics, and preventing dissemination of pathogen variants carrying new infectivity or resistance to agrochemicals.
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Affiliation(s)
- Jiasui Zhan
- Key Laboratory for Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, 350002, China;
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Wang Y, Khatabi B, Hajimorad MR. Amino acid substitution in P3 of Soybean mosaic virus to convert avirulence to virulence on Rsv4-genotype soybean is influenced by the genetic composition of P3. MOLECULAR PLANT PATHOLOGY 2015; 16:301-7. [PMID: 25040594 PMCID: PMC6638367 DOI: 10.1111/mpp.12175] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The modification of avirulence factors of plant viruses by one or more amino acid substitutions converts avirulence to virulence on hosts containing resistance genes. Limited experimental studies have been conducted on avirulence/virulence factors of plant viruses, in particular those of potyviruses, to determine whether avirulence/virulence sites are conserved among strains. In this study, the Soybean mosaic virus (SMV)-Rsv4 pathosystem was exploited to determine whether: (i) avirulence/virulence determinants of SMV reside exclusively on P3 regardless of virus strain; and (ii) the sites residing on P3 and crucial for avirulence/virulence of isolates belonging to strain G2 are also involved in virulence of avirulent isolates belonging to strain G7. The results confirm that avirulence/virulence determinants of SMV on Rsv4-genotype soybean reside exclusively on P3. Furthermore, the data show that sites involved in the virulence of SMV on Rsv4-genotype soybean vary among strains, with the genetic composition of P3 playing a crucial role.
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Affiliation(s)
- Y Wang
- Department of Entomology and Plant Pathology, The University of Tennessee, Knoxville, TN, 37996, USA
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Peiró A, Cañizares MC, Rubio L, López C, Moriones E, Aramburu J, Sánchez-Navarro J. The movement protein (NSm) of Tomato spotted wilt virus is the avirulence determinant in the tomato Sw-5 gene-based resistance. MOLECULAR PLANT PATHOLOGY 2014; 15:802-13. [PMID: 24690181 PMCID: PMC6638753 DOI: 10.1111/mpp.12142] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The avirulence determinant triggering the resistance conferred by the tomato gene Sw-5 against Tomato spotted wilt virus (TSWV) is still unresolved. Sequence comparison showed two substitutions (C118Y and T120N) in the movement protein NSm present only in TSWV resistance-breaking (RB) isolates. In this work, transient expression of NSm of three TSWV isolates [RB1 (T120N), RB2 (C118Y) and non-resistance-breaking (NRB)] in Nicotiana benthamiana expressing Sw-5 showed a hypersensitive response (HR) only with NRB. Exchange of the movement protein of Alfalfa mosaic virus (AMV) with NSm supported cell-to-cell and systemic transport of the chimeric AMV RNAs into N. tabacum with or without Sw-5, except for the constructs with NBR when Sw-5 was expressed, although RB2 showed reduced cell-to-cell transport. Mutational analysis revealed that N120 was sufficient to avoid the HR, but the substitution V130I was required for systemic transport. Finally, co-inoculation of RB and NRB AMV chimeric constructs showed different prevalence of RB or NBR depending on the presence or absence of Sw-5. These results indicate that NSm is the avirulence determinant for Sw-5 resistance, and mutations C118Y and T120N are responsible for resistance breakdown and have a fitness penalty in the context of the heterologous AMV system.
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Affiliation(s)
- Ana Peiró
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, 46022, Valencia, Spain
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Abstract
Viruses are common agents of plant infectious diseases. During last decades, worldwide agriculture production has been compromised by a series of epidemics caused by new viruses that spilled over from reservoir species or by new variants of classic viruses that show new pathogenic and epidemiological properties. Virus emergence has been generally associated with ecological change or with intensive agronomical practices. However, the complete picture is much more complex since the viral populations constantly evolve and adapt to their new hosts and vectors. This chapter puts emergence of plant viruses into the framework of evolutionary ecology, genetics, and epidemiology. We will stress that viral emergence begins with the stochastic transmission of preexisting genetic variants from the reservoir to the new host, whose fate depends on their fitness on each hosts, followed by adaptation to new hosts or vectors, and finalizes with an efficient epidemiological spread.
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Affiliation(s)
- Santiago F Elena
- Instituto de Biología Molecular y Celular de Plantas, CSIC-UPV, Campus UPV, València, Spain; The Santa Fe Institute, Santa Fe, New Mexico, USA
| | - Aurora Fraile
- Centro de Biotecnología y Genómica de Plantas, UPM-INIA, and ETSI Agrónomos, UPM, Campus de Montegancedo, Madrid, Spain
| | - Fernando García-Arenal
- Centro de Biotecnología y Genómica de Plantas, UPM-INIA, and ETSI Agrónomos, UPM, Campus de Montegancedo, Madrid, Spain.
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31
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Mizumoto H, Morikawa Y, Ishibashi K, Kimura K, Matsumoto K, Tokunaga M, Kiba A, Ishikawa M, Okuno T, Hikichi Y. Functional characterization of the mutations in Pepper mild mottle virus overcoming tomato tm-1-mediated resistance. MOLECULAR PLANT PATHOLOGY 2014; 15:479-487. [PMID: 24299004 PMCID: PMC6638807 DOI: 10.1111/mpp.12107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In tomato plants, Pepper mild mottle virus (PMMoV) cannot replicate because the tm-1 protein inhibits RNA replication. The resistance of tomato plants to PMMoV remains durable both in the field and under laboratory conditions. In this study, we constructed several mutant PMMoVs and analysed their abilities to replicate in tomato protoplasts and plants. We found that two mutants, PMMoV-899R,F976Y and PMMoV-899R,F976Y,D1098N, were able to replicate in tomato protoplasts, but only PMMoV-899R,F976Y,D1098N was able to multiply in tomato plants. Further analysis showed that the D1098N mutation of the replication proteins weakened the inhibitory effect of the tm-1 protein and enhanced the replication efficiency of PMMoV-899R,F976Y,D1098N. We also observed that the infectivity of the viruses decreased in the order wild-type PMMoV > PMMoV-899R,F976Y > PMMoV-899R,F976Y,D1098N in original host plants, pepper and tobacco plants. On the contrary, the single mutation D1098N abolished PMMoV replication in tobacco protoplasts. On the basis of these observations, it is likely that the deleterious side-effects of mutations in replication proteins prevent the emergence of PMMoV mutants that can overcome tm-1-mediated resistance.
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Affiliation(s)
- Hiroyuki Mizumoto
- Laboratory of Plant Pathology and Biotechnology, Kochi University, Nankoku, Kochi, 783-8502, Japan
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32
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Fraile A, Hily JM, Pagán I, Pacios LF, García-Arenal F. Host resistance selects for traits unrelated to resistance-breaking that affect fitness in a plant virus. Mol Biol Evol 2014; 31:928-39. [PMID: 24441034 DOI: 10.1093/molbev/msu045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
The acquisition by parasites of the capacity to infect resistant host genotypes, that is, resistance-breaking, is predicted to be hindered by across-host fitness trade-offs. All analyses of costs of resistance-breaking in plant viruses have focused on within-host multiplication without considering other fitness components, which may limit understanding of virus evolution. We have reported that host range expansion of tobamoviruses on L-gene resistant pepper genotypes was associated with severe within-host multiplication penalties. Here, we analyze whether resistance-breaking costs might affect virus survival in the environment by comparing tobamovirus pathotypes differing in infectivity on L-gene resistance alleles. We predicted particle stability from structural models, analyzed particle stability in vitro, and quantified virus accumulation in different plant organs and virus survival in the soil. Survival in the soil differed among tobamovirus pathotypes and depended on differential stability of virus particles. Structure model analyses showed that amino acid changes in the virus coat protein (CP) responsible for resistance-breaking affected the strength of the axial interactions among CP subunits in the rod-shaped particle, thus determining its stability and survival. Pathotypes ranked differently for particle stability/survival and for within-host accumulation. Resistance-breaking costs in survival add to, or subtract from, costs in multiplication according to pathotype. Hence, differential pathotype survival should be considered along with differential multiplication to understand the evolution of the virus populations. Results also show that plant resistance, in addition to selecting for resistance-breaking and for decreased multiplication, also selects for changes in survival, a trait unrelated to the host-pathogen interaction that may condition host range expansion.
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Affiliation(s)
- Aurora Fraile
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA) and E.T.S.I. Agrónomos, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
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Construction of a genetic map based on high-throughput SNP genotyping and genetic mapping of a TuMV resistance locus in Brassica rapa. Mol Genet Genomics 2013; 289:149-60. [DOI: 10.1007/s00438-013-0798-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 12/03/2013] [Indexed: 12/18/2022]
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Khatabi B, Wen RH, Hajimorad MR. Fitness penalty in susceptible host is associated with virulence of Soybean mosaic virus on Rsv1-genotype soybean: a consequence of perturbation of HC-Pro and not P3. MOLECULAR PLANT PATHOLOGY 2013; 14:885-97. [PMID: 23782556 PMCID: PMC6638797 DOI: 10.1111/mpp.12054] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The multigenic Rsv1 locus in the soybean plant introduction (PI) 'PI96983' confers extreme resistance against the majority of Soybean mosaic virus (SMV) strains, including SMV-N, but not SMV-G7 and SMV-G7d. In contrast, in susceptible soybean cultivars lacking a functional Rsv1 locus, such as 'Williams82' (rsv1), SMV-N induces severe disease symptoms and accumulates to a high level, whereas both SMV-G7 and SMV-G7d induce mild symptoms and accumulate to a significantly lower level. Gain of virulence by SMV-N on Rsv1-genotype soybean requires concurrent mutations in both the helper-component proteinase (HC-Pro) and P3 cistrons. This is because of the presence of at least two resistance (R) genes, probably belonging to the nucleotide-binding leucine-rich repeat (NB-LRR) class, within the Rsv1 locus, independently mediating the recognition of HC-Pro or P3. In this study, we show that the majority of experimentally evolved mutational pathways that disrupt the avirulence functions of SMV-N on Rsv1-genotype soybean also result in mild symptoms and reduced accumulation, relative to parental SMV-N, in Williams82 (rsv1). Furthermore, the evaluation of SMV-N-derived HC-Pro and P3 chimeras, containing homologous sequences from virulent SMV-G7 or SMV-G7d strains, as well as SMV-N-derived variants containing HC-Pro or P3 point mutation(s) associated with gain of virulence, reveals a direct correlation between the perturbation of HC-Pro and a fitness penalty in Williams82 (rsv1). Collectively, these data demonstrate that gain of virulence by SMV on Rsv1-genotype soybean results in fitness loss in a previously susceptible soybean genotype, this being a consequence of mutations in HC-Pro, but not in P3.
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Affiliation(s)
- B Khatabi
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN, 37996, USA
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35
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Bornemann K, Varrelmann M. Effect of sugar beet genotype on the Beet necrotic yellow vein virus P25 pathogenicity factor and evidence for a fitness penalty in resistance-breaking strains. MOLECULAR PLANT PATHOLOGY 2013; 14:356-64. [PMID: 23282068 PMCID: PMC6638868 DOI: 10.1111/mpp.12012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Beet necrotic yellow vein virus (BNYVV), vectored by Polymyxa betae, causes rhizomania in sugar beet. For disease control, the cultivation of hybrids carrying Rz1 resistance is crucial, but is compromised by resistance-breaking (RB) strains with specific mutations in the P25 protein at amino acids 67-70 (tetrad). To obtain evidence for P25 variability from soil-borne populations, where the virus persists for decades, populations with wild-type (WT) and RB properties were analysed by P25 deep sequencing. The level of P25 variation in the populations analysed did not correlate with RB properties. Remarkably, one WT population contained P25 with RB mutations at a frequency of 11%. To demonstrate selection by Rz1 and the influence of RB mutations on relative fitness, competition experiments between strains were performed. Following a mixture of strains with four RNAs, a shift in tetrad variants was observed, suggesting that strains did not mix or transreplicate. The plant genotype exerted a clear influence on the frequency of RB tetrads. In Rz1 plants, the RB variants outcompeted the WT variants, and mostly vice versa in susceptible plants, demonstrating a relative fitness penalty of RB mutations. The strong genotype effect supports the hypothesized Rz1 RB strain selection with four RNAs, suggesting that a certain tetrad needs to become dominant in a population to influence its properties. Tetrad selection was not observed when an RB strain, with an additional P26 protein encoded by a fifth RNA, competed with a WT strain, supporting its role as a second BNYVV pathogenicity factor and suggesting the reassortment of both types.
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Affiliation(s)
- Kathrin Bornemann
- Department of Phytopathology, Institute of Sugar Beet Research, D-37079, Goettingen, Germany
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36
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Acosta-Leal R, Xiong Z. Intrahost mechanisms governing emergence of resistance-breaking variants of Potato virus Y. Virology 2013; 437:39-47. [PMID: 23332684 DOI: 10.1016/j.virol.2012.12.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2012] [Revised: 12/01/2012] [Accepted: 12/02/2012] [Indexed: 10/27/2022]
Abstract
The emergence of resistance breaking (RB) variants starting from the avirulent Potato virus Y NN strain (PVY(NN)) was analyzed after imposing different selective host constraints. Tobacco resistance to PVY(NN) is conferred by va in both NC745 and VAM genotypes, but VAM carries an extra resistance gene, va2. RB-variants emerged only in NC745 and unexpectedly accumulated higher in the original host, tobacco B21, than the parental PVY(NN). However, the recovery of RB-variants was interfered by PVY(NN) in mixed infections. Further analysis indicated that RB-variants also arose in tobacco VAM, but they were limited to subliminal local infections. Their inability to breakout was associated with absence of a mutational adaptation in the viral VPg gene, which implied a loss of fitness in tobacco B21. Altogether, the emergence of RB-variants was conditioned by inherited host constraints, interference by co-infecting avirulent virus genotypes, and fitness tradeoff of virus adaptations.
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Affiliation(s)
- Rodolfo Acosta-Leal
- School of Plant Sciences and BIO5 Institute, University of Arizona, Forbes 303, Tucson, AZ 85721, USA.
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37
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Zhan J, McDonald BA. Experimental measures of pathogen competition and relative fitness. ANNUAL REVIEW OF PHYTOPATHOLOGY 2013; 51:131-53. [PMID: 23767846 DOI: 10.1146/annurev-phyto-082712-102302] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Competition among pathogen strains for limited host resources can have a profound effect on pathogen evolution. A better understanding of the principles and consequences of competition can be useful in designing more sustainable disease management strategies. The competitive ability and relative fitness of a pathogen strain are determined by its intrinsic biological properties, the resistance and heterogeneity of the corresponding host population, the population density and genetic relatedness of the competing strains, and the physical environment. Competitive ability can be inferred indirectly from fitness components, such as basic reproduction rate or transmission rate. However, pathogen strains that exhibit higher fitness components when they infect a host alone may not exhibit a competitive advantage when they co-infect the same host. The most comprehensive measures of competitive ability and relative fitness come from calculating selection coefficients in a mixed infection in a field setting. Mark-release-recapture experiments can be used to estimate fitness costs associated with unnecessary virulence and fungicide resistance.
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Affiliation(s)
- Jiasui Zhan
- Key Lab for Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
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38
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Montarry J, Cartier E, Jacquemond M, Palloix A, Moury B. Virus adaptation to quantitative plant resistance: erosion or breakdown? J Evol Biol 2012; 25:2242-52. [DOI: 10.1111/j.1420-9101.2012.02600.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 07/19/2012] [Accepted: 07/21/2012] [Indexed: 11/30/2022]
Affiliation(s)
| | - E. Cartier
- INRA; UR407 Pathologie Végétale; Montfavet; France
| | | | - A. Palloix
- INRA; UR1052 Génétique et Amélioration des Fruits et Légumes (GAFL); Montfavet; France
| | - B. Moury
- INRA; UR407 Pathologie Végétale; Montfavet; France
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Bever JD, Platt TG, Morton ER. Microbial population and community dynamics on plant roots and their feedbacks on plant communities. Annu Rev Microbiol 2012; 66:265-83. [PMID: 22726216 PMCID: PMC3525954 DOI: 10.1146/annurev-micro-092611-150107] [Citation(s) in RCA: 228] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The composition of the soil microbial community can be altered dramatically due to association with individual plant species, and these effects on the microbial community can have important feedbacks on plant ecology. Negative plant-soil feedback plays primary roles in maintaining plant community diversity, whereas positive plant-soil feedback may cause community conversion. Host-specific differentiation of the microbial community results from the trade-offs associated with overcoming plant defense and the specific benefits associated with plant rewards. Accumulation of host-specific pathogens likely generates negative feedback on the plant, while changes in the density of microbial mutualists likely generate positive feedback. However, the competitive dynamics among microbes depends on the multidimensional costs of virulence and mutualism, the fine-scale spatial structure within plant roots, and active plant allocation and localized defense. Because of this, incorporating a full view of microbial dynamics is essential to explaining the dynamics of plant-soil feedbacks and therefore plant community ecology.
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Affiliation(s)
- James D. Bever
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Thomas G. Platt
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Elise R. Morton
- Department of Biology, Indiana University, Bloomington, Indiana 47405
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Zhan J, Yang L, Zhu W, Shang L, Newton AC. Pathogen populations evolve to greater race complexity in agricultural systems--evidence from analysis of Rhynchosporium secalis virulence data. PLoS One 2012; 7:e38611. [PMID: 22723870 PMCID: PMC3377678 DOI: 10.1371/journal.pone.0038611] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Accepted: 05/08/2012] [Indexed: 11/19/2022] Open
Abstract
Fitness cost associated with pathogens carrying unnecessary virulence alleles is the fundamental assumption for preventing the emergence of complex races in plant pathogen populations but this hypothesis has rarely been tested empirically on a temporal and spatial scale which is sufficient to distinguish evolutionary signals from experimental error. We analyzed virulence characteristics of ≈ 1000 isolates of the barley pathogen Rhynchosporium secalis collected from different parts of the United Kingdom between 1984 and 2005. We found a gradual increase in race complexity over time with a significant correlation between sampling date and race complexity of the pathogen (r(20) = 0.71, p = 0.0002) and an average loss of 0.1 avirulence alleles (corresponding to an average gain of 0.1 virulence alleles) each year. We also found a positive and significant correlation between barley cultivar diversity and R. secalis virulence variation. The conditions assumed to favour complex races were not present in the United Kingdom and we hypothesize that the increase in race complexity is attributable to the combination of natural selection and genetic drift. Host resistance selects for corresponding virulence alleles to fixation or dominant frequency. Because of the weak fitness penalty of carrying the unnecessary virulence alleles, genetic drift associated with other evolutionary forces such as hitch-hiking maintains the frequency of the dominant virulence alleles even after the corresponding resistance factors cease to be used.
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Affiliation(s)
- Jiasui Zhan
- Key Lab for Biopesticide and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, China.
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41
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Moury B, Simon V. dN/dS-based methods detect positive selection linked to trade-offs between different fitness traits in the coat protein of potato virus Y. Mol Biol Evol 2011; 28:2707-17. [PMID: 21498601 DOI: 10.1093/molbev/msr105] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The dN/dS ratio between nonsynonymous and synonymous substitution rates has been used extensively to identify codon positions involved in adaptive processes. However, the accuracy of this approach has been questioned, and very few studies have attempted to validate experimentally its predictions. Using the coat protein (CP) of Potato virus Y (PVY; genus Potyvirus, family Potyviridae) as a case study, we identified several candidate positively selected codon positions that differed between clades. In the CP of the N clade of PVY, positive selection was detected at codon positions 25 and 68 by both the softwares PAML and HyPhy. We introduced nonsynonymous substitutions at these positions in an infectious cDNA clone of PVY and measured the effect of these mutations on virus accumulation in its two major cultivated hosts, tobacco and potato, and on its efficiency of transmission from plant to plant by aphid vectors. The mutation at codon position 25 significantly modified the virus accumulation in the two hosts, whereas the mutation at codon position 68 significantly modified the virus accumulation in one of its hosts and its transmissibility by aphids. Both mutations were involved in adaptive trade-offs. We suggest that our study was particularly favorable to the detection of adaptive mutations using dN/dS estimates because, as obligate parasites, viruses undergo a continuous and dynamic interaction with their hosts that favors the recurrent selection of adaptive mutations and because trade-offs between different fitness traits impede (or at least slow down) the fixation of these mutations and maintain polymorphism within populations.
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Affiliation(s)
- Benoît Moury
- UR407 Pathologie Végétale, Institut National de la Recherche Agronomique, Montfavet, France.
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42
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Desbiez C, Moury B, Lecoq H. The hallmarks of "green" viruses: do plant viruses evolve differently from the others? INFECTION GENETICS AND EVOLUTION 2011; 11:812-24. [PMID: 21382520 DOI: 10.1016/j.meegid.2011.02.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 02/22/2011] [Accepted: 02/24/2011] [Indexed: 12/13/2022]
Abstract
All viruses are obligatory parasites that must develop tight interactions with their hosts to complete their infectious cycle. Viruses infecting plants share many structural and functional similarities with those infecting other organisms, particularly animals and fungi. Quantitative data regarding their evolutionary mechanisms--generation of variability by mutation and recombination, changes in populations by selection and genetic drift have been obtained only recently, and appear rather similar to those measured for animal viruses.This review presents an update of our knowledge of the phylogenetic and evolutionary characteristics of plant viruses and their relation to their plant hosts, in comparison with viruses infecting other organisms.
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Affiliation(s)
- C Desbiez
- INRA, Unité de Pathologie Végétale UR407, F-84140 Montfavet, France.
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Elena SF, Bedhomme S, Carrasco P, Cuevas JM, de la Iglesia F, Lafforgue G, Lalić J, Pròsper A, Tromas N, Zwart MP. The evolutionary genetics of emerging plant RNA viruses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:287-93. [PMID: 21294624 DOI: 10.1094/mpmi-09-10-0214] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Over the years, agriculture across the world has been compromised by a succession of devastating epidemics caused by new viruses that spilled over from reservoir species or by new variants of classic viruses that acquired new virulence factors or changed their epidemiological patterns. Viral emergence is usually associated with ecological change or with agronomical practices bringing together reservoirs and crop species. The complete picture is, however, much more complex, and results from an evolutionary process in which the main players are ecological factors, viruses' genetic plasticity, and host factors required for virus replication, all mixed with a good measure of stochasticity. The present review puts emergence of plant RNA viruses into the framework of evolutionary genetics, stressing that viral emergence begins with a stochastic process that involves the transmission of a preexisting viral strain into a new host species, followed by adaptation to the new host.
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Affiliation(s)
- Santiago F Elena
- Instituto de Biologia Molecular, Consejo Superior de Investigaciones Cientificas, Valencia, Spain.
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Tentchev D, Verdin E, Marchal C, Jacquet M, Aguilar JM, Moury B. Evolution and structure of Tomato spotted wilt virus populations: evidence of extensive reassortment and insights into emergence processes. J Gen Virol 2010; 92:961-73. [DOI: 10.1099/vir.0.029082-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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Fraile A, Pagán I, Anastasio G, Sáez E, García-Arenal F. Rapid genetic diversification and high fitness penalties associated with pathogenicity evolution in a plant virus. Mol Biol Evol 2010; 28:1425-37. [PMID: 21131559 DOI: 10.1093/molbev/msq327] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Under the gene-for-gene model of host-pathogen coevolution, recognition of pathogen avirulence factors by host resistance factors triggers host defenses and limits infection. Theory predicts that the evolution of higher levels of pathogenicity will be associated with fitness penalties and that the cost of higher pathogenicity must be much smaller than that of not infecting the host. The analysis of pathogenicity costs is of academic and applied relevance, as these are determinants for the success of resistance genes bred into crops for disease control. However, most previous attempts of addressing this issue in plant pathogens yielded conflicting and inconclusive results. We have analyzed the costs of pathogenicity in pepper-infecting tobamoviruses defined by their ability to infect pepper plants with different alleles at the resistance locus L. We provide conclusive evidence of pathogenicity-associated costs by comparison of pathotype frequency with the fraction of the crop carrying the various resistance alleles, by timescaled phylogenies, and by temporal analyses of population dynamics and selection pressures using nucleotide sequences. In addition, experimental estimates of relative fitness under controlled conditions also provided evidence of high pathogenicity costs. These high pathogenicity costs may reflect intrinsic properties of plant virus genomes and should be considered in future models of host-parasite coevolution.
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Affiliation(s)
- Aurora Fraile
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA) and ETSI Agrónomos, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Madrid, Spain
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46
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Montarry J, Hamelin FM, Glais I, Corbi R, Andrivon D. Fitness costs associated with unnecessary virulence factors and life history traits: evolutionary insights from the potato late blight pathogen Phytophthora infestans. BMC Evol Biol 2010; 10:283. [PMID: 20846405 PMCID: PMC2949872 DOI: 10.1186/1471-2148-10-283] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 09/16/2010] [Indexed: 11/10/2022] Open
Abstract
Background In gene-for-gene models of plant-pathogen interactions, the existence of fitness costs associated with unnecessary virulence factors still represents an issue, both in evolutionary biology and agricultural sciences. Measuring such costs experimentally has proven difficult, especially in pathogens not readily amenable to genetic transformation, since the creation of isogenic lines differing only by the presence or absence of avirulence genes cannot be achieved in many organisms. Here, we circumvented this difficulty by comparing fitness traits in groups of Phytophthora infestans isolates sharing the same multilocus fingerprint, but differing by their virulence/avirulence spectrum. Results Fitness was assessed from calculations derived from the basic reproduction number, combining several life history traits (latent period, spore density and lesion growth rate) evaluated on leaflets of the potato cultivar Bintje, which is free of resistance genes. A statistically significant fitness cost was found in isolates virulent to the R10 resistance gene. That cost was due to a lower spore production in virulent isolates; however, the latent period was shorter in virulent isolates. Similar trends, although not statistically significant, were observed for the other genes tested. Conclusion The data likely reflect the adaptive response of the pathogen to the cost associated with virulence. They suggest strong trade-offs between life history traits related to pathogenicity and adaptive biology of pathogens.
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Affiliation(s)
- Josselin Montarry
- INRA, Agrocampus-Ouest, UMR1099 BiO3P, Biology of Organisms and Populations applied to Plant Protection, F-35653 Le Rheu, France.
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Inferring the evolutionary history of the plant pathogen Pseudomonas syringae from its biogeography in headwaters of rivers in North America, Europe, and New Zealand. mBio 2010; 1. [PMID: 20802828 PMCID: PMC2925074 DOI: 10.1128/mbio.00107-10] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 06/02/2010] [Indexed: 11/26/2022] Open
Abstract
Nonhost environmental reservoirs of pathogens play key roles in their evolutionary ecology and in particular in the evolution of pathogenicity. In light of recent reports of the plant pathogen Pseudomonas syringae in pristine waters outside agricultural regions and its dissemination via the water cycle, we have examined the genetic and phenotypic diversity, population structure, and biogeography of P. syringae from headwaters of rivers on three continents and their phylogenetic relationship to strains from crops. A collection of 236 strains from 11 sites in the United States, in France, and in New Zealand was characterized for genetic diversity based on housekeeping gene sequences and for phenotypic diversity based on measures of pathogenicity and ice nucleation activity. Phylogenetic analyses revealed several new genetic clades from water. The genetic structure of P. syringae populations was not influenced by geographic location or water chemistry, whereas the phenotypic structure was affected by these parameters. Comparison with strains from crops revealed that the metapopulation of P. syringae is structured into three genetic ecotypes: a crop-specific type, a water-specific type, and an abundant ecotype found in both habitats. Aggressiveness of strains was significantly and positively correlated with ice nucleation activity. Furthermore, the ubiquitous genotypes were the most aggressive, on average. The abundance and diversity in water relative to crops suggest that adaptation to the freshwater habitat has played a nonnegligible role in the evolutionary history of P. syringae. We discuss how adaptation to the water cycle is linked to the epidemiological success of this plant pathogen. Many pathogens have life cycles that involve survival and multiplication in nonhost environmental habitats. For human pathogens, numerous studies have revealed how adaptation to environmental habitats is linked to the evolution of their pathogenicity and emergence of pathogens. For plant pathogens, the link between adaptation to nonhost habitats and pathogenicity has not been explored. Here we have examined the genetic and phenotypic diversity of the plant pathogen Pseudomonas syringae in headwaters of rivers on three continents and compared it to that of strains from crops. This model pathogen was chosen because it is widely abundant in habitats associated with the water cycle and in particular in pristine waters outside agricultural regions. This work reveals that there is considerable exchange of populations between freshwater and agricultural habitats and that those in the former contribute considerably to the diversification of P. syringae.
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Janzac B, Montarry J, Palloix A, Navaud O, Moury B. A point mutation in the polymerase of Potato virus Y confers virulence toward the Pvr4 resistance of pepper and a high competitiveness cost in susceptible cultivar. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:823-830. [PMID: 20459321 DOI: 10.1094/mpmi-23-6-0823] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
To understand why the Pvr4 resistance of pepper against Potyvirus spp. remained durable in field conditions while virulent Potato virus Y (PVY) variants could be selected in the laboratory, we studied the molecular mechanisms which generated these variants and the consequences on viral fitness. Using a reverse genetics approach with an infectious cDNA clone of PVY, we found that the region coding for the NIb protein (RNA-dependent RNA polymerase) of PVY was the avirulence factor corresponding to Pvr4 and that a single nonsynonymous nucleotide substitution in that region, an adenosine to guanosine substitution at position 8,424 of the PVY genome (A(8424)G), was sufficient for virulence. This substitution imposed a high competitiveness cost to the virus against an avirulent PVY variant in plants devoid of Pvr4. In addition, during serial passages in susceptible pepper plants, the only observed possibility of the virulent mutant to increase its fitness was through the G(8424)A reversion, strengthening the high durability potential of the Pvr4 resistance. This is in accordance with the fact that the NIb protein is one of the most constrained proteins expressed by the PVY genome and, more generally, by Potyvirus spp., and with a previously developed model predicting the durability of virus resistances as a function of the evolutionary constraint applied on corresponding avirulence factors.
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49
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Fraile A, García-Arenal F. The coevolution of plants and viruses: resistance and pathogenicity. Adv Virus Res 2010; 76:1-32. [PMID: 20965070 DOI: 10.1016/s0065-3527(10)76001-2] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Virus infection may damage the plant, and plant defenses are effective against viruses; thus, it is currently assumed that plants and viruses coevolve. However, and despite huge advances in understanding the mechanisms of pathogenicity and virulence in viruses and the mechanisms of virus resistance in plants, evidence in support of this hypothesis is surprisingly scant, and refers almost only to the virus partner. Most evidence for coevolution derives from the study of highly virulent viruses in agricultural systems, in which humans manipulate host genetic structure, what determines genetic changes in the virus population. Studies have focused on virus responses to qualitative resistance, either dominant or recessive but, even within this restricted scenario, population genetic analyses of pathogenicity and resistance factors are still scarce. Analyses of quantitative resistance or tolerance, which could be relevant for plant-virus coevolution, lag far behind. A major limitation is the lack of information on systems in which the host might evolve in response to virus infection, that is, wild hosts in natural ecosystems. It is presently unknown if, or under which circumstances, viruses do exert a selection pressure on wild plants, if qualitative resistance is a major defense strategy to viruses in nature, or even if characterized genes determining qualitative resistance to viruses did indeed evolve in response to virus infection. Here, we review evidence supporting plant-virus coevolution and point to areas in need of attention to understand the role of viruses in plant ecosystem dynamics, and the factors that determine virus emergence in crops.
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Affiliation(s)
- Aurora Fraile
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA) and E.T.S.I. Agrónomos, Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, Madrid, Spain
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50
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Janzac B, Fabre F, Palloix A, Moury B. Constraints on evolution of virus avirulence factors predict the durability of corresponding plant resistances. MOLECULAR PLANT PATHOLOGY 2009; 10:599-610. [PMID: 19694951 PMCID: PMC6640373 DOI: 10.1111/j.1364-3703.2009.00554.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
SUMMARY Understanding the factors driving pathogen emergence and re-emergence is a major challenge, particularly in agriculture, where the use of resistant plant cultivars imposes strong selective pressures on plant pathogen populations and leads frequently to 'resistance breakdown'. Presently, durable resistances are only identified after a long period of large-scale cultivation of resistant cultivars. We propose a new predictor of the durability of plant resistance. Because resistance breakdown involves modifications in the avirulence factors of pathogens, we tested for correlations between the evolutionary constraints acting on avirulence factors or their diversity and the durability of the corresponding resistance genes in the case of plant-virus interactions. An analysis performed on 20 virus species-resistance gene combinations revealed that the selective constraints applied on amino acid substitutions in virus avirulence factors correlate with the observed durability of the corresponding resistance genes. On the basis of this result, a model predicting the potential durability of resistance genes as a function of the selective constraints applied on the corresponding avirulence factors is proposed to help breeders to select the most durable resistance genes.
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Affiliation(s)
- Berenger Janzac
- INRA, UR407 Pathologie Végétale, Domaine Saint Maurice, BP94, F-84140 Montfavet, France.
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