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Ratnaparkhe MB, Wang X, Li J, Compton RO, Rainville LK, Lemke C, Kim C, Tang H, Paterson AH. Comparative analysis of peanut NBS-LRR gene clusters suggests evolutionary innovation among duplicated domains and erosion of gene microsynteny. THE NEW PHYTOLOGIST 2011; 192:164-178. [PMID: 21707619 DOI: 10.1111/j.1469-8137.2011.03800.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
• Plant genomes contain numerous disease resistance genes (R genes) that play roles in defense against pathogens. Scarcity of genetic polymorphism makes peanut (Arachis hypogaea) especially vulnerable to a wide variety of pathogens. • Here, we isolated and characterized peanut bacterial artificial chromosomes (BACs) containing a high density of R genes. Analysis of two genomic regions identified several TIR-NBS-LRR (Toll-interleukin-1 receptor, nucleotide-binding site, leucine-rich repeat) resistance gene analogs or gene fragments. We reconstructed their evolutionary history characterized by tandem duplications, possibly facilitated by transposon activities. We found evidence of both intergenic and intragenic gene conversions and unequal crossing-over, which may be driving forces underlying the functional evolution of resistance. • Analysis of the sequence mutations, protein secondary structure and three-dimensional structures, all suggest that LRR domains are the primary contributor to the evolution of resistance genes. The central part of LRR regions, assumed to serve as the active core, may play a key role in the resistance function by having higher rates of duplication and DNA conversion than neighboring regions. The assumed active core is characterized by significantly enriched leucine residue composition, accumulation of positively selected sites, and shorter beta sheets. • Homologous resistance gene analog (RGA)-containing regions in peanut, soybean, Medicago, Arabidopsis and grape have only limited gene synteny and microcollinearity.
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Affiliation(s)
| | - Xiyin Wang
- Plant Genome Mapping Laboratory, University of Georgia, Athens, GA 30602, USA
- Center for Genomics and Computational Biology, School of Life Sciences, School of Sciences, Hebei United University, Tangshan, Hebei 063000, China
| | - Jingping Li
- Plant Genome Mapping Laboratory, University of Georgia, Athens, GA 30602, USA
| | - Rosana O Compton
- Plant Genome Mapping Laboratory, University of Georgia, Athens, GA 30602, USA
| | - Lisa K Rainville
- Plant Genome Mapping Laboratory, University of Georgia, Athens, GA 30602, USA
| | - Cornelia Lemke
- Plant Genome Mapping Laboratory, University of Georgia, Athens, GA 30602, USA
| | - Changsoo Kim
- Plant Genome Mapping Laboratory, University of Georgia, Athens, GA 30602, USA
| | - Haibao Tang
- Plant Genome Mapping Laboratory, University of Georgia, Athens, GA 30602, USA
| | - Andrew H Paterson
- Plant Genome Mapping Laboratory, University of Georgia, Athens, GA 30602, USA
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52
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Komatsu K, Hashimoto M, Maejima K, Shiraishi T, Neriya Y, Miura C, Minato N, Okano Y, Sugawara K, Yamaji Y, Namba S. A necrosis-inducing elicitor domain encoded by both symptomatic and asymptomatic Plantago asiatica mosaic virus isolates, whose expression is modulated by virus replication. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:408-20. [PMID: 21190438 DOI: 10.1094/mpmi-12-10-0279] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Systemic necrosis is the most destructive symptom induced by plant pathogens. We previously identified amino acid 1154, in the polymerase domain (POL) of RNA-dependent RNA polymerase (RdRp) of Plantago asiatica mosaic virus (PlAMV), which affects PlAMV-induced systemic necrosis in Nicotiana benthamiana. By point-mutation analysis, we show that amino acid 1,154 alone is not sufficient for induction of necrotic symptoms. However, PlAMV replicons that can express only RdRp, derived from a necrosis-inducing PlAMV isolate, retain their ability to induce necrosis, and transient expression of PlAMV-encoded proteins indicated that the necrosis-eliciting activity resides in RdRp. Moreover, inducible-overexpression analysis demonstrated that the necrosis was induced in an RdRp dose-dependent manner. In addition, during PlAMV infection, necrotic symptoms are associated with high levels of RdRp accumulation. Surprisingly, necrosis-eliciting activity resides in the helicase domain (HEL), not in the amino acid 1,154-containing POL, of RdRp, and this activity was observed even in HELs of PlAMV isolates of which infection does not cause necrosis. Moreover, HEL-induced necrosis had characteristics similar to those induced by PlAMV infection. Overall, our data suggest that necrotic symptoms induced by PlAMV infection depend on the accumulation of a non-isolate specific elicitor HEL (even from nonnecrosis isolates), whose expression is indirectly regulated by amino acid 1,154 that controls replication.
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Affiliation(s)
- Ken Komatsu
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
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53
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García-Neria MA, Rivera-Bustamante RF. Characterization of Geminivirus resistance in an accession of Capsicum chinense Jacq. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:172-182. [PMID: 20923365 DOI: 10.1094/mpmi-06-10-0126] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Pepper golden mosaic virus (PepGMV) and Pepper huasteco yellow vein virus (PHYVV), members of the Geminiviridae family, are important pathogens of pepper (Capsicum annuum L.) and other solanaceous crops. Accession BG-3821 of C. chinense Jacq. was reported earlier as resistant to mixed infection with PepGMV and PHYVV. In this work, we characterized the Geminivirus resistance trait present in BG-3821. Segregation analysis suggested that resistance depends on two genes. Our data showed that PepGMV replication in protoplast of resistant plants is approximately 70% lower when compared with the levels observed in protoplasts from susceptible plants. Additionally, viral movement is less efficient in resistant plants. We also evaluated several characteristics commonly associated with systemic acquired resistance (SAR), which is a conserved defensive mechanism. The concentration of salicylic acid was higher in resistant plants inoculated with PepGMV than in susceptible plants. Marker genes for SAR were induced after inoculation with PepGMV in resistant leaves. Similarly, we found a higher accumulation of reactive oxygen species on resistant leaves compared with susceptible ones. A model for the mechanism acting in the Geminivirus resistance detected in BG-3821 is proposed. Finally, the importance of BG-3821 in Geminivirus resistance breeding programs is discussed.
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Affiliation(s)
- Marco A García-Neria
- Departamento de Ingeniería Genética, Cinvestav Unidad Irapuato, Km 9.6 Libramiento Norte, Carretera Irapuato-León, 36821, Irapuato, Gto, Mexico
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54
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Terefe-Ayana D, Yasmin A, Le TL, Kaufmann H, Biber A, Kühr A, Linde M, Debener T. Mining disease-resistance genes in roses: functional and molecular characterization of the rdr1 locus. FRONTIERS IN PLANT SCIENCE 2011; 2:35. [PMID: 22639591 PMCID: PMC3355636 DOI: 10.3389/fpls.2011.00035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 07/18/2011] [Indexed: 05/03/2023]
Abstract
The interaction of roses with the leaf spot pathogen Diplocarpon rosae (the cause of black spot on roses) is an interesting pathosystem because it involves a long-lived woody perennial, with life history traits very different from most model plants, and a hemibiotrophic pathogen with moderate levels of gene flow. Here we present data on the molecular structure of the first monogenic dominant resistance gene from roses, Rdr1, directed against one isolate of D. rosae. Complete sequencing of the locus carrying the Rdr1 gene resulted in a sequence of 265,477 bp with a cluster of nine highly related TIR-NBS-LRR (TNL) candidate genes. After sequencing revealed candidate genes for Rdr1, we implemented a gene expression analysis and selected five genes out of the nine TNLs. We then silenced the whole TNL gene family using RNAi (Rdr1-RNAi) constructed from the most conserved sequence region and demonstrated a loss of resistance in the normally resistant genotype. To identify the functional TNL gene, we further screened the five TNL candidate genes with a transient leaf infiltration assay. The transient expression assay indicated a single TNL gene (muRdr1H), partially restoring resistance in the susceptible genotype. Rdr1 was found to localize within the muRdr1 gene family; the genes within this locus contain characteristic motifs of active TNL genes and belong to a young cluster of R genes. The transient leaf assay can be used to further analyze the rose black spot interaction and its evolution, extending the analyses to additional R genes and to additional pathogenic types of the pathogen.
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Affiliation(s)
- Diro Terefe-Ayana
- Institute for Plant Genetics, Leibniz University HannoverHannover, Germany
| | - Aneela Yasmin
- Institute for Plant Genetics, Leibniz University HannoverHannover, Germany
| | - Thanh Loan Le
- Institute for Plant Genetics, Leibniz University HannoverHannover, Germany
| | - Helgard Kaufmann
- Institute for Plant Genetics, Leibniz University HannoverHannover, Germany
| | - Anja Biber
- Institute for Plant Genetics, Leibniz University HannoverHannover, Germany
| | - Astrid Kühr
- Institute for Plant Genetics, Leibniz University HannoverHannover, Germany
| | - Marcus Linde
- Institute for Plant Genetics, Leibniz University HannoverHannover, Germany
| | - Thomas Debener
- Institute for Plant Genetics, Leibniz University HannoverHannover, Germany
- *Correspondence: Thomas Debener, Institute for Plant Genetics, Leibniz University Hannover, Herrenhäuser Str. 2, D-30419 Hannover, Germany. e-mail:
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55
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Panwar P, Jha AK, Pandey PK, Gupta AK, Kumar A. Functional markers based molecular characterization and cloning of resistance gene analogs encoding NBS-LRR disease resistance proteins in finger millet (Eleusine coracana). Mol Biol Rep 2010; 38:3427-36. [DOI: 10.1007/s11033-010-0452-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 11/08/2010] [Indexed: 11/27/2022]
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56
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Ingvardsen CR, Xing Y, Frei UK, Lübberstedt T. Genetic and physical fine mapping of Scmv2, a potyvirus resistance gene in maize. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2010; 120:1621-34. [PMID: 20155410 DOI: 10.1007/s00122-010-1281-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Accepted: 01/24/2010] [Indexed: 05/08/2023]
Abstract
Sugarcane mosaic virus (SCMV) is an important virus pathogen both in European and Chinese maize production, causing serious losses in grain and forage yield in susceptible cultivars. Two major resistance loci confer resistance to SCMV, one located on chromosome 3 (Scmv2) and one on chromosome 6 (Scmv1). We developed a large isogenic mapping population segregating in the Scmv2, but not the Scmv1 region, to minimize genetic variation potentially affecting expression of SCMV resistance. We fine mapped Scmv2 to a region of 0.28 cM, covering a physical distance of 1.3426 Mb, and developed six new polymorphic SSR markers based on publicly available BAC sequences within this region. At present, we still have three recombinants left between Scmv2 and the nearest polymorphic marker on either side of the Scmv2 locus. The region showed synteny to a 1.6 Mb long sequence on chromosome 12 in rice. Analysis of the public B73 BAC library as well as the syntenic rice region did not reveal any similarity to known resistance genes. However, four new candidate genes with a possible involvement in movement of virus were detected.
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Affiliation(s)
- Christina Roenn Ingvardsen
- Department of Genetics and Biotechnology, Faculty of Agricultural Sciences, University of Aarhus, Forsøgsvej 1, 4200, Slagelse, Denmark.
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57
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Liu SY, Yu K, Huffner M, Park SJ, Banik M, Pauls KP, Crosby W. Construction of a BAC library and a physical map of a major QTL for CBB resistance of common bean (Phaseolus vulgaris L.). Genetica 2010; 138:709-16. [PMID: 20419470 DOI: 10.1007/s10709-010-9450-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2009] [Accepted: 02/25/2010] [Indexed: 11/29/2022]
Abstract
A major quantitative trait loci (QTL) conditioning common bacterial blight (CBB) resistance in common bean (Phaseolus vulgaris L.) lines HR45 and HR67 was derived from XAN159, a resistant line obtained from an interspecific cross between common bean lines and the tepary bean (P. acutifolius L.) line PI319443. This source of CBB resistance is widely used in bean breeding. Several other CBB resistance QTL have been identified but none of them have been physically mapped. Four molecular markers tightly linked to this QTL have been identified suitable for marker assisted selection and physical mapping of the resistance gene. A bacterial artificial chromosome (BAC) library was constructed from high molecular weight DNA of HR45 and is composed of 33,024 clones. The size of individual BAC clone inserts ranges from 30 kb to 280 kb with an average size of 107 kb. The library is estimated to represent approximately sixfold genome coverage. The BAC library was screened as BAC pools using four PCR-based molecular markers. Two to seven BAC clones were identified by each marker. Two clones were found to have both markers PV-tttc001 and STS183. One preliminary contig was assembled based on DNA finger printing of those positive BAC clones. The minimum tiling path of the contig contains 6 BAC clones spanning an estimated size of 750 kb covering the QTL region.
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Affiliation(s)
- S Y Liu
- Agriculture Agri-Food Canada, Greenhouse and Processing Crops Research Center, Harrow, ON, N0R 1G0, Canada
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58
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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: 63] [Impact Index Per Article: 4.5] [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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59
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Shi C, Chaudhary S, Yu K, Park SJ, Navabi A, McClean PE. Identification of candidate genes associated with CBB resistance in common bean HR45 (Phaseolus vulgaris L.) using cDNA-AFLP. Mol Biol Rep 2010; 38:75-81. [PMID: 20300860 DOI: 10.1007/s11033-010-0079-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Accepted: 03/05/2010] [Indexed: 12/22/2022]
Abstract
Common bacterial blight (CBB), incited by Xanthomonas axonopodis pv. phaseoli (Xap), is a serious seed-borne disease of common bean (Phaseolus vulgaris L.) in both temperate and tropical production zones. The line HR45 is highly resistant to Xap infection on leaves and pods in both field and greenhouse. To understand the molecular mechanisms underlying CBB resistance in HR45, cDNA-amplified fragment length polymorphism (AFLP) technique was used to identify the genes that are differentially expressed in the leaves of HR45 at different time-periods after inoculation. Selective amplifications with 34 primer combinations allowed the visualization of 2,448 transcript-derived fragments (TDFs) in infected leaves, and 259 (10.6%) of them were differentially expressed TDFs (DE-TDFs). Seventy-seven of the DE-TDFs were cloned and sequenced. Thirty-nine of the 77 (50.6%) DE-TDFs representing bean transcripts were not previously reported in any EST database. The expression patterns of 10 representative DE-TDFs were further confirmed by real-time RT-PCR. BLAST analysis suggested that 40% (31 of 77) of the DE-TDFs were homologous to the genes related to metabolism, photosynthesis, and cellular transport, whereas 28% (22 of 77) of the DE-TDFs showed homology to the genes involved in defence response, response to stimulus, enzyme regulation, and transcription regulation. Thus, the 22 pathogenesis-related DE-TDFs were selected as potential functional candidate genes (FCGs) in association with CBB resistance. Meanwhile, six of the DE-TDFs (1FCG and five other DE-TDFs) were in silico mapped to the distal region of the bean linkage group B6 (the genomic location containing the major CBB resistance QTL in HR45) and, therefore, were considered as positional candidate genes (PCGs). This study represents a first step towards the discovery of bean genes expressed upon Xap infection. This information will be useful for elucidating the molecular basis of the resistance response process and identifying the genes that underlie the CBB-resistance.
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Affiliation(s)
- Chun Shi
- Greenhouse and Processing Crops Research Centre, Agriculture and Agri-Food Canada, Harrow, ON, N0R 1G0, Canada
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60
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Komatsu K, Hashimoto M, Ozeki J, Yamaji Y, Maejima K, Senshu H, Himeno M, Okano Y, Kagiwada S, Namba S. Viral-induced systemic necrosis in plants involves both programmed cell death and the inhibition of viral multiplication, which are regulated by independent pathways. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:283-93. [PMID: 20121450 DOI: 10.1094/mpmi-23-3-0283] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Resistant plants respond rapidly to invading avirulent plant viruses by triggering a hypersensitive response (HR). An HR is accompanied by a restraint of virus multiplication and programmed cell death (PCD), both of which have been observed in systemic necrosis triggered by a successful viral infection. Here, we analyzed signaling pathways underlying the HR in resistance genotype plants and those leading to systemic necrosis. We show that systemic necrosis in Nicotiana benthamiana, induced by Plantago asiatica mosaic virus (PlAMV) infection, was associated with PCD, biochemical features, and gene expression patterns that are characteristic of HR. The induction of necrosis caused by PlAMV infection was dependent on SGT1, RAR1, and the downstream mitogen-activated protein kinase (MAPK) cascade involving MAPKKKalpha and MEK2. However, although SGT1 and RAR1 silencing led to an increased accumulation of PlAMV, silencing of the MAPKKKalpha-MEK2 cascade did not. This observation indicates that viral multiplication is partly restrained even in systemic necrosis induced by viral infection, and that this restraint requires SGT1 and RAR1 but not the MAPKKKalpha-MEK2 cascade. Similarly, although both SGT1 and MAPKKKalpha were essential for the Rx-mediated HR to Potato virus X (PVX), SGT1 but not MAPKKKalpha was involved in the restraint of PVX multiplication. These results suggest that systemic necrosis and HR consist of PCD and a restraint of virus multiplication, and that the latter is induced through unknown pathways independent from the former.
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Affiliation(s)
- Ken Komatsu
- Laboratory Of Plant Pathology, Department Of Agricultural And Environmental Biology, Graduate School Of Agricultural And Life Sciences, The University Of Tokyo, Tokyo, Japan
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61
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Miklas PN, Seo YS, Gilbertson RL. Quantitative Resistance to Bean dwarf mosaic virus in Common Bean Is Associated with the Bct Gene for Resistance to Beet curly top virus. PLANT DISEASE 2009; 93:645-648. [PMID: 30764403 DOI: 10.1094/pdis-93-6-0645] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The dominant resistance gene, Bct, in common bean (Phaseolus vulgaris) confers qualitative resistance to Beet curly top virus, a leafhopper-transmitted geminivirus in the genus Curtovirus. To determine whether this gene confers resistance to other geminiviruses, bean plants of a recombinant inbred population were sap-inoculated with Bean dwarf mosaic virus (BDMV), a whitefly-transmitted bipartite begomovirus in the genus Begomovirus. Results indicated that Bct (or tightly linked gene) is associated with quantitative resistance to BDMV; thus, the Bct locus is associated with resistance to a bean-infecting begomovirus and curtovirus. The difference in the nature of the resistance to these geminiviruses may indicate a role for minor genes in begomovirus resistance or differences in the virus-host interaction. The Bct locus, whether it acts alone or represents a cluster of tightly linked genes, will be useful in breeding for broad-spectrum begomovirus resistance in common bean.
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Affiliation(s)
- P N Miklas
- USDA-ARS, Vegetable and Forage Crop Research Unit, Prosser, WA 99350
| | - Y-S Seo
- Department of Plant Pathology, University of California, Davis 95616
| | - R L Gilbertson
- Department of Plant Pathology, University of California, Davis 95616
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62
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Chen LF, Rojas M, Kon T, Gamby K, Xoconostle-Cazares B, Gilbertson RL. A severe symptom phenotype in tomato in Mali is caused by a reassortant between a novel recombinant begomovirus (Tomato yellow leaf curl Mali virus) and a betasatellite. MOLECULAR PLANT PATHOLOGY 2009; 10:415-30. [PMID: 19400843 PMCID: PMC6640326 DOI: 10.1111/j.1364-3703.2009.00541.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Tomato production in West Africa has been severely affected by begomovirus diseases, including yellow leaf curl and a severe symptom phenotype, characterized by extremely stunted and distorted growth and small deformed leaves. Here, a novel recombinant begomovirus from Mali, Tomato yellow leaf curl Mali virus (TYLCMLV), is described that, alone, causes tomato yellow leaf curl disease or, in combination with a betasatellite, causes the severe symptom phenotype. TYLCMLV is an Old World monopartite begomovirus with a hybrid genome composed of sequences from Tomato yellow leaf curl virus-Mild (TYLCV-Mld) and Hollyhock leaf crumple virus (HoLCrV). A TYLCMLV infectious clone induced leaf curl and yellowing in tomato, leaf curl, crumpling and yellowing in Nicotiana benthamiana and common bean, mild symptoms in N. glutinosa, and a symptomless infection in Datura stramonium. In a field-collected sample from a tomato plant showing the severe symptom phenotype in Mali, TYLCMLV was detected together with a betasatellite, identified as Cotton leaf curl Gezira betasatellite (CLCuGB). Tomato plants co-agroinoculated with TYLCMLV and CLCuGB developed severely stunted and distorted growth and small crumpled leaves. These symptoms were more severe than those induced by TYLCMLV alone, and were similar to the severe symptom phenotype observed in the field in Mali and in other West African countries. TYLCMLV and CLCuGB also induced more severe symptoms than TYLCMLV in the other solanaceous hosts, but not in common bean. The increased symptom severity was associated with hyperplasia of phloem-associated cells, but relatively little increase in TYLCMLV DNA levels. In surveys of tomato virus diseases in West Africa, TYLCMLV was commonly detected in plants with leaf curl and yellow leaf curl symptoms, whereas CLCuGB was infrequently detected and always in association with the severe symptom phenotype. Together, these results indicate that TYLCMLV causes tomato yellow leaf curl disease throughout West Africa, whereas TYLCMLV and CLCuGB represent a reassortant that causes the severe symptom phenotype in tomato.
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Affiliation(s)
- Li-Fang Chen
- Department of Plant Pathology, University of California, Davis, CA 95616, USA
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63
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Cloning and structure analysis of an NBS-LRR disease-resistant gene from Setaria italica Beauv. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/s11703-009-0035-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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64
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Essafi A, Díaz-Pendón JA, Moriones E, Monforte AJ, Garcia-Mas J, Martín-Hernández AM. Dissection of the oligogenic resistance to Cucumber mosaic virus in the melon accession PI 161375. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2009; 118:275-84. [PMID: 18825359 DOI: 10.1007/s00122-008-0897-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Accepted: 09/12/2008] [Indexed: 05/03/2023]
Abstract
Resistance to Cucumber mosaic virus (CMV) in the exotic melon accession PI 161375, cultivar "Sonwang Charmi" (SC) had previously been described as oligogenic, recessive and quantitative, with a major QTL residing in linkage group XII (LGXII). We have used a collection of near isogenic lines (NILs) with introgressions of SC into the genome of the susceptible accession Piel de Sapo (PS) to further characterise this resistance. Infection of NILs carrying introgressions on LGXII showed that only NIL SC12-1 was resistant to CMV strains P9 and P104.82, but not to strains M6 and TL. Further mapping of this region showed that the resistance, named cmv1 maps in an area of 2.2 cM, between markers CMN61_44 and CMN21_55. Moreover, cmv1 confers total resistance to strains P9 and P104.82, indicating that in these cases it is not quantitative and that cmv1 is sufficient to confer full resistance to these CMV strains. Candidate gene mapping of ten translation initiation factors in the melon genome failed to find any of them in the interval between markers CMN61_44 and CMN21_55. All these results suggest that the resistance to CMV present in SC is oligogenic, where different loci confer resistance to different CMV strains, but not necessarily quantitative, since at least one of these genes (cmv1) confers total resistance, similar to that of the parental SC, and does not need the contribution of other loci.
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Affiliation(s)
- Ali Essafi
- IRTA, Centre de Recerca en Agrigenòmica CSIC-IRTA-UAB, Carretera de Cabrils, Km 2, 08348, Cabrils, Barcelona, Spain
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65
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Hagen C, Rojas MR, Kon T, Gilbertson RL. Recovery from Cucurbit leaf crumple virus (family Geminiviridae, genus Begomovirus) infection is an adaptive antiviral response associated with changes in viral small RNAs. PHYTOPATHOLOGY 2008; 98:1029-37. [PMID: 18943741 DOI: 10.1094/phyto-98-9-1029] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
A strong recovery response occurs in cantaloupe (Cucumis melo) and watermelon (Citrullus lanatus) infected with the bipartite begomovirus Cucurbit leaf crumple virus (CuLCrV). This response is characterized by initially severe symptoms, which gradually become attenuated (almost symptomless). An inverse relationship was detected between viral DNA levels and recovery, indicating that recovered tissues had reduced viral titers. Recovered tissues also were resistant to reinfection with CuLCrV; i.e., recovered leaves reinoculated with the virus did not develop symptoms or have an increased level of viral DNA. In contrast, infection of CuLCrV-recovered leaves with the RNA virus, Cucumber mosaic virus (CMV), disrupted recovery, resulting in the development of severe disease symptoms (more severe than those induced by CMV or CuLCrV alone) and increased CuLCrV DNA levels. Small RNAs with homology to CuLCrV DNA were detected in recovered and nonrecovered tissues; as well as in phloem exudates from infected, but not uninfected plants. Levels of these small RNAs were positively correlated with viral titer; thus, recovered tissues had lower levels than symptomatic tissues. In addition, viral DNA from a host that undergoes strong recovery (watermelon) was more highly methylated compared with that from a host that undergoes limited recovery (zucchini). Furthermore, inoculation of CuLCrV-infected zucchini with a construct expressing an inverted repeat of the CuLCrV common region enhanced recovery and reduced viral symptoms and viral DNA levels in newly emerged leaves. Taken together, these results suggest that recovery from CuLCrV infection is an adaptive antiviral defense mechanism, most likely mediated by gene silencing.
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Affiliation(s)
- C Hagen
- Department of Plant Pathology, University of California-Davis, 95616, USA
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Yang S, Gao M, Xu C, Gao J, Deshpande S, Lin S, Roe BA, Zhu H. Alfalfa benefits from Medicago truncatula: the RCT1 gene from M. truncatula confers broad-spectrum resistance to anthracnose in alfalfa. Proc Natl Acad Sci U S A 2008; 105:12164-9. [PMID: 18719113 PMCID: PMC2527883 DOI: 10.1073/pnas.0802518105] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Indexed: 12/28/2022] Open
Abstract
Alfalfa is economically the most important forage legume worldwide. A recurrent challenge to alfalfa production is the significant yield loss caused by disease. Although knowledge of molecular mechanisms underlying host resistance should facilitate the genetic improvement of alfalfa, the acquisition of such knowledge is hampered by alfalfa's tetrasomic inheritance and outcrossing nature. However, alfalfa is congeneric with the reference legume Medicago truncatula, providing an opportunity to use M. truncatula as a surrogate to clone the counterparts of many agronomically important genes in alfalfa. In particular, the high degree of sequence identity and remarkably conserved genome structure and function between the two species enables M. truncatula genes to be used directly in alfalfa improvement. Here we report the map-based cloning of RCT1, a host resistance (R) gene in M. truncatula that confers resistance to multiple races of Colletotrichum trifolii, a hemibiotrophic fungal pathogen that causes anthracnose disease of alfalfa. RCT1 is a member of the Toll-interleukin-1 receptor/nucleotide-binding site/leucine-rich repeat (TIR-NBS-LRR) class of plant R genes and confers broad-spectrum anthracnose resistance when transferred into susceptible alfalfa plants. Thus, RCT1 provides a novel resource to develop anthracnose-resistant alfalfa cultivars and contributes to our understanding of host resistance against the fungal genus Colletotrichum. This work demonstrates the potential of using M. truncatula genes for genetic improvement of alfalfa.
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Affiliation(s)
- Shengming Yang
- *Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546; and
| | - Muqiang Gao
- *Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546; and
| | - Chenwu Xu
- *Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546; and
| | - Jianchang Gao
- *Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546; and
| | - Shweta Deshpande
- Advanced Center for Genome Technology, Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73109
| | - Shaoping Lin
- Advanced Center for Genome Technology, Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73109
| | - Bruce A. Roe
- Advanced Center for Genome Technology, Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73109
| | - Hongyan Zhu
- *Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546; and
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Balaji B, Cawly J, Angel C, Zhang Z, Palanichelvam K, Cole A, Schoelz J. Silencing of the N family of resistance genes in Nicotiana edwardsonii compromises the hypersensitive response to tombusviruses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2007; 20:1262-70. [PMID: 17918628 DOI: 10.1094/mpmi-20-10-1262] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The nontarget effects associated with silencing of the N gene in Nicotiana edwardsonii, an amphidiploid species derived from N. glutinosa and N. clevelandii, have been characterized in this study. The N protein confers resistance to Tobacco mosaic virus (TMV), and is representative of a family of nucleotide-binding site leucine-rich repeat proteins present in N. glutinosa. Previous studies have shown that silencing of the N gene or of other plant genes associated with N-mediated defenses abolishes host resistance to TMV, and this effect can be measured through enhancements in movement or replication of TMV in the N-silenced plants. However, the nontarget effects of gene silencing have not been investigated thoroughly. Notably, are the functions of other resistance (R) genes also affected in experiments designed to silence the N gene? To investigate whether heterologous sequences could silence the N gene, we selected an R gene homolog from N. glutinosa that differed from the N gene by approximately 17%, created a hairpin transgene, and developed transgenic N. edwardsonii plants. Expression of this hairpin in the transgenic N. edwardsonii plants compromised the hypersensitive response to TMV, demonstrating that a single hairpin transgene could silence a block of R genes related by sequence similarity. We then investigated whether the response of N-silenced plants to other viruses would be altered, and found that the hypersensitive response triggered against the tombusviruses Tomato bushy stunt virus and Cymbidium ringspot virus also was compromised. This study indicates that a Tombusvirus R gene shares some homology with the N gene, which could facilitate the cloning of this gene.
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Seo YS, Jeon JS, Rojas MR, Gilbertson RL. Characterization of a novel Toll/interleukin-1 receptor (TIR)-TIR gene differentially expressed in common bean (Phaseolus vulgaris cv. Othello) undergoing a defence response to the geminivirus Bean dwarf mosaic virus. MOLECULAR PLANT PATHOLOGY 2007; 8:151-62. [PMID: 20507487 DOI: 10.1111/j.1364-3703.2007.00379.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
SUMMARY Common bean (Phaseolus vulgaris L.) cultivar (cv.) Othello develops a hypersensitive response-associated vascular resistance to infection by Bean dwarf mosaic virus (BDMV), a single-stranded DNA virus (genus Begomovirus, family Geminiviridae). A PCR-based cDNA subtraction approach was used to identify genes involved in this resistance response. Eighteen clones, potentially involved with BDMV resistance, were identified based upon being up-regulated in BDMV-infected tissues and/or having sequence similarity with known resistance-associated genes. Analysis of these clones revealed potential genes involved in pathogen defence, including pathogenesis-related protein genes and resistance gene analogues (RGAs). Further characterization of one RGA, F1-10, revealed that it encodes a predicted protein with a double Toll/interleukin-1 receptor (TIR) motif. Full-length (F1-10) and spliced (F1-10sp) forms of the RGA were strongly up-regulated in BDMV-infected cv. Othello hypocotyl tissues by 4 days post-inoculation, but not in equivalent mock-inoculated tissues. In agroinfiltration experiments, F1-10, but not F1-10sp, mediated resistance to BDMV in the susceptible common bean cv. Topcrop. By contrast, transgenic Nicotiana benthamiana lines expressing F1-10 or F1-10sp were not resistant to BDMV. Interestingly, when these transgenic lines were inoculated with the potyvirus Bean yellow mosaic virus, some F1-10 lines showed a more severe symptom phenotype compared with non-transgenic control plants. Based on these findings, F1-10 was named: Phaseolus vulgaris VIRUS response TIR-TIR GENE 1 (PvVTT1).
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Affiliation(s)
- Young-Su Seo
- Department of Plant Pathology, University of California, Davis, CA 95616, USA
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Maule AJ, Caranta C, Boulton MI. Sources of natural resistance to plant viruses: status and prospects. MOLECULAR PLANT PATHOLOGY 2007; 8:223-31. [PMID: 20507494 DOI: 10.1111/j.1364-3703.2007.00386.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
SUMMARY Globally, virus diseases are common in agricultural crops and have a major agronomic impact. They are countered through the deployment of genetic resistance against the virus, or through the use of a range of farming practices based upon the propagation of virus-free plant material and the exclusion of the virus vectors from the growing crop. We review here the current status of our knowledge of natural virus resistance genes, and consider the future prospects for the deployment of these genes against virus infection.
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Affiliation(s)
- Andrew J Maule
- John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, UK
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