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Zhang J, Sun J, Chiu CH, Landry D, Li K, Wen J, Mysore KS, Fort S, Lefebvre B, Oldroyd GED, Feng F. A receptor required for chitin perception facilitates arbuscular mycorrhizal associations and distinguishes root symbiosis from immunity. Curr Biol 2024; 34:1705-1717.e6. [PMID: 38574729 PMCID: PMC11037463 DOI: 10.1016/j.cub.2024.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 02/15/2024] [Accepted: 03/12/2024] [Indexed: 04/06/2024]
Abstract
Plants establish symbiotic associations with arbuscular mycorrhizal fungi (AMF) to facilitate nutrient uptake, particularly in nutrient-limited conditions. This partnership is rooted in the plant's ability to recognize fungal signaling molecules, such as chitooligosaccharides (chitin) and lipo-chitooligosaccharides. In the legume Medicago truncatula, chitooligosaccharides trigger both symbiotic and immune responses via the same lysin-motif-receptor-like kinases (LysM-RLKs), notably CERK1 and LYR4. The nature of plant-fungal engagement is opposite according to the outcomes of immunity or symbiosis signaling, and as such, discrimination is necessary, which is challenged by the dual roles of CERK1/LYR4 in both processes. Here, we describe a LysM-RLK, LYK8, that is functionally redundant with CERK1 for mycorrhizal colonization but is not involved in chitooligosaccharides-induced immunity. Genetic mutation of both LYK8 and CERK1 blocks chitooligosaccharides-triggered symbiosis signaling, as well as mycorrhizal colonization, but shows no further impact on immunity signaling triggered by chitooligosaccharides, compared with the mutation of CERK1 alone. LYK8 interacts with CERK1 and forms a receptor complex that appears essential for chitooligosaccharides activation of symbiosis signaling, with the lyk8/cerk1 double mutant recapitulating the impact of mutations in the symbiosis signaling pathway. We conclude that this novel receptor complex allows chitooligosaccharides activation specifically of symbiosis signaling and helps the plant to differentiate between activation of these opposing signaling processes.
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Affiliation(s)
- Jingyi Zhang
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Jongho Sun
- Crop Science Centre, Department of Plant Sciences, University of Cambridge, Cambridge CB3 0LE, UK
| | - Chai Hao Chiu
- Crop Science Centre, Department of Plant Sciences, University of Cambridge, Cambridge CB3 0LE, UK
| | - David Landry
- Laboratory of Plant-Microbe-Environment Interactions (LIPME), Université de Toulouse, INRAE, CNRS, Castanet-Tolosan 31326, France
| | - Kangping Li
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Jiangqi Wen
- Institute for Agricultural Biosciences, Oklahoma State University, Ardmore, OK 73401, USA; Department of Plant and Soil Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - Kirankumar S Mysore
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA; Institute for Agricultural Biosciences, Oklahoma State University, Ardmore, OK 73401, USA
| | - Sébastien Fort
- Université de Grenoble Alpes, CNRS, CERMAV, 38000 Grenoble, France
| | - Benoit Lefebvre
- Laboratory of Plant-Microbe-Environment Interactions (LIPME), Université de Toulouse, INRAE, CNRS, Castanet-Tolosan 31326, France
| | - Giles E D Oldroyd
- Crop Science Centre, Department of Plant Sciences, University of Cambridge, Cambridge CB3 0LE, UK.
| | - Feng Feng
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA.
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Kankanala P, Jones P, Nandety RS, Jacobson DA, Mysore KS. Plasticity of Phymatotrichopsis omnivora infection strategies is dependent on host and nonhost plant responses. Plant Cell Environ 2020; 43:1084-1101. [PMID: 31930733 PMCID: PMC7154777 DOI: 10.1111/pce.13721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 01/06/2020] [Accepted: 01/08/2020] [Indexed: 06/10/2023]
Abstract
Necrotrophic fungi constitute the largest group of plant fungal pathogens that cause heavy crop losses worldwide. Phymatotrichopsis omnivora is a broad host, soil-borne necrotrophic fungal pathogen that infects over 2,000 dicotyledonous plants. The molecular basis of such broad host range is unknown. We conducted cell biology and transcriptomic studies in Medicago truncatula (susceptible), Brachypodium distachyon (resistant/nonhost), and Arabidopsis thaliana (partially resistant) to understand P. omnivora virulence mechanisms. We performed defence gene analysis, gene enrichments, and correlational network studies during key infection stages. We identified that P. omnivora infects the susceptible plant as a traditional necrotroph. However, it infects the partially resistant plant as a hemi-biotroph triggering salicylic acid-mediated defence pathways in the plant. Further, the infection strategy in partially resistant plants is determined by the host responses during early infection stages. Mutant analyses in A. thaliana established the role of small peptides PEP1 and PEP2 in defence against P. omnivora. The resistant/nonhost B. distachyon triggered stress responses involving sugars and aromatic acids. Bdwat1 mutant analysis identified the role of cell walls in defence. This is the first report that describes the plasticity in infection strategies of P. omnivora providing insights into broad host range.
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Affiliation(s)
| | - Piet Jones
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
- Bredesen Center for Interdisciplinary StudiesUniversity of Tennessee KnoxvilleKnoxvilleTennessee
| | | | - Daniel A. Jacobson
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTennessee
- Bredesen Center for Interdisciplinary StudiesUniversity of Tennessee KnoxvilleKnoxvilleTennessee
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3
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Feng F, Sun J, Radhakrishnan GV, Lee T, Bozsóki Z, Fort S, Gavrin A, Gysel K, Thygesen MB, Andersen KR, Radutoiu S, Stougaard J, Oldroyd GED. A combination of chitooligosaccharide and lipochitooligosaccharide recognition promotes arbuscular mycorrhizal associations in Medicago truncatula. Nat Commun 2019; 10:5047. [PMID: 31695035 PMCID: PMC6834629 DOI: 10.1038/s41467-019-12999-5] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 10/03/2019] [Indexed: 12/02/2022] Open
Abstract
Plants associate with beneficial arbuscular mycorrhizal fungi facilitating nutrient acquisition. Arbuscular mycorrhizal fungi produce chitooligosaccharides (COs) and lipo-chitooligosaccharides (LCOs), that promote symbiosis signalling with resultant oscillations in nuclear-associated calcium. The activation of symbiosis signalling must be balanced with activation of immunity signalling, which in fungal interactions is promoted by COs resulting from the chitinaceous fungal cell wall. Here we demonstrate that COs ranging from CO4-CO8 can induce symbiosis signalling in Medicago truncatula. CO perception is a function of the receptor-like kinases MtCERK1 and LYR4, that activate both immunity and symbiosis signalling. A combination of LCOs and COs act synergistically to enhance symbiosis signalling and suppress immunity signalling and receptors involved in both CO and LCO perception are necessary for mycorrhizal establishment. We conclude that LCOs, when present in a mix with COs, drive a symbiotic outcome and this mix of signals is essential for arbuscular mycorrhizal establishment.
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Affiliation(s)
- Feng Feng
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge, CB2 1LR, UK
| | - Jongho Sun
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge, CB2 1LR, UK
| | - Guru V Radhakrishnan
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, NR4 7UH, UK
| | - Tak Lee
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge, CB2 1LR, UK
| | - Zoltán Bozsóki
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, 8000 C, Denmark
| | - Sébastien Fort
- Université de Grenoble Alpes, CNRS, CERMAV, 38000, Grenoble, France
| | - Aleksander Gavrin
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge, CB2 1LR, UK
| | - Kira Gysel
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, 8000 C, Denmark
| | - Mikkel B Thygesen
- Department of Chemistry, University of Copenhagen, Frederiksberg, 1871 C, Denmark
| | | | - Simona Radutoiu
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, 8000 C, Denmark
| | - Jens Stougaard
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, 8000 C, Denmark
| | - Giles E D Oldroyd
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge, CB2 1LR, UK.
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Cui N, Lu H, Wang T, Zhang W, Kang L, Cui F. Armet, an aphid effector protein, induces pathogen resistance in plants by promoting the accumulation of salicylic acid. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180314. [PMID: 30967016 PMCID: PMC6367143 DOI: 10.1098/rstb.2018.0314] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2018] [Indexed: 12/20/2022] Open
Abstract
Effector proteins present in aphid saliva are thought to modulate aphid-plant interactions. Armet, an effector protein, is found in the phloem sap of pea-aphid-infested plants and is indispensable for the survival of aphids on plants. However, its function in plants has not been investigated. Here, we explored the functions of Armet after delivery into plants. Examination of the transcriptomes of Nicotiana benthamiana and Medicago truncatula following transgenic expression of Armet or infiltration of the protein showed that Armet activated pathways associated with plant-pathogen interactions, mitogen-activated protein kinase and salicylic acid (SA). Armet induced a fourfold increase in SA accumulation by regulating the expression of SAMT and SABP2, two genes associated with SA metabolism, in Armet-infiltrated tobacco. The increase in SA enhanced the plants' resistance to bacterial pathogen Pseudomonas syringae but had no detectable adverse effects on aphid survival or reproduction. Similar molecular responses and a chlorosis phenotype were induced in tobacco by Armet from two aphid species but not by locust Armet, suggesting that the effector function of Armet may be specific for aphids. The results suggest that Armet causes plants to make a pathogen-resistance decision and reflect a novel tripartite insect-plant-pathogen interaction. This article is part of the theme issue 'Biotic signalling sheds light on smart pest management'.
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Affiliation(s)
- Na Cui
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Hong Lu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
| | - Tianzuo Wang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People's Republic of China
| | - Wenhao Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Le Kang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Feng Cui
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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5
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Rey T, André O, Nars A, Dumas B, Gough C, Bottin A, Jacquet C. Lipo-chitooligosaccharide signalling blocks a rapid pathogen-induced ROS burst without impeding immunity. New Phytol 2019; 221:743-749. [PMID: 30378690 DOI: 10.1111/nph.15574] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Accepted: 10/23/2018] [Indexed: 06/08/2023]
Abstract
Molecular signals released by microbes at the surface of plant roots and leaves largely determine host responses, notably by triggering either immunity or symbiosis. How these signalling pathways cross-talk upon coincident perception of pathogens and symbionts is poorly described in plants forming symbiosis. Nitrogen fixing symbiotic Rhizobia spp. and arbuscular mycorrhizal fungi produce lipo-chitooligosaccharides (LCOs) to initiate host symbiotic programmes. In Medicago truncatula roots, the perception of LCOs leads to reduced efflux of reactive oxygen species (ROS). By contrast, pathogen perception generally triggers a strong ROS burst and activates defence gene expression. Here we show that incubation of M. truncatula seedlings with culture filtrate (CF) of the legume pathogen Aphanomyces euteiches alone or simultaneously with Sinorhizobium meliloti LCOs, resulted in a strong ROS release. However, this response was completely inhibited if CF was added after pre-incubation of seedlings with LCOs. By contrast, expression of immunity-associated genes in response to CF and disease resistance to A. euteiches remained unaffected by LCO treatment of M. truncatula roots. Our findings suggest that symbiotic plants evolved ROS inhibition response to LCOs to facilitate early steps of symbiosis whilst maintaining a parallel defence mechanisms toward pathogens.
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Affiliation(s)
- Thomas Rey
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 24 chemin de Borde Rouge, Auzeville, BP42617, 31326, Castanet Tolosan, France
| | - Olivier André
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 24 chemin de Borde Rouge, Auzeville, BP42617, 31326, Castanet Tolosan, France
| | - Amaury Nars
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 24 chemin de Borde Rouge, Auzeville, BP42617, 31326, Castanet Tolosan, France
| | - Bernard Dumas
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 24 chemin de Borde Rouge, Auzeville, BP42617, 31326, Castanet Tolosan, France
| | - Clare Gough
- Laboratory of Plant-Microbe Interactions (LIPM), Université de Toulouse, INRA, CNRS, 31326, Castanet-Tolosan, France
| | - Arnaud Bottin
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 24 chemin de Borde Rouge, Auzeville, BP42617, 31326, Castanet Tolosan, France
| | - Christophe Jacquet
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 24 chemin de Borde Rouge, Auzeville, BP42617, 31326, Castanet Tolosan, France
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6
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Yu H, Xiao A, Dong R, Fan Y, Zhang X, Liu C, Wang C, Zhu H, Duanmu D, Cao Y, Zhang Z. Suppression of innate immunity mediated by the CDPK-Rboh complex is required for rhizobial colonization in Medicago truncatula nodules. New Phytol 2018; 220:425-434. [PMID: 30129677 DOI: 10.1111/nph.15410] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 07/23/2018] [Indexed: 05/28/2023]
Abstract
Suppression of innate immunity is essential for rhizobial infection and colonization in compatible interactions with leguminous plants. In Medicago nad1 mutant plants, innate immunity is excessively activated, resulting in necrotic cell death after rhizobia are released from infection threads into symbiotic cells, suggesting that innate immunity plays a critical role in regulating bacteroid persistence. In this study, we identified three respiratory burst oxidase homologs (Rboh) and one calcium-dependent protein kinase (CDPK) as key factors for the activation of immunity in Medicago nodules using genetic and biochemical methods. Knock-out of either MtRbohB or MtRbohD in nad1-1 mutant plants produced effective nodules with intact symbiotic cells, while knock-out of MtRbohC decreased brown pigment deposition, leading to less necrosis in nad1-1 mutant nodules. MtCDPK5 directly phosphorylated MtRbohB, MtRbohC and MtRbohD, which triggered immune responses in plants. Knock-out of MtCDPK5 in nad1-1 mutant plants partially restored nitrogen-fixing nodules. Overexpression of the constitutively activated variant MtCDPK5VK under the control of the NAD1 promoter elicited strong immune responses, resulting in ineffective nodules in wild-type plants. Our data provide direct evidence that host plants utilize innate immunity to regulate rhizobial colonization in symbiotic cells in Medicago truncatula.
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Affiliation(s)
- Haixiang Yu
- State Key Laboratory of Agricultural Microbiology, Center of Integrative Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Aifang Xiao
- State Key Laboratory of Agricultural Microbiology, Center of Integrative Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Ru Dong
- State Key Laboratory of Agricultural Microbiology, Center of Integrative Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yuqian Fan
- State Key Laboratory of Agricultural Microbiology, Center of Integrative Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xianpeng Zhang
- State Key Laboratory of Agricultural Microbiology, Center of Integrative Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Chao Liu
- State Key Laboratory of Agricultural Microbiology, Center of Integrative Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Chao Wang
- State Key Laboratory of Agricultural Microbiology, Center of Integrative Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Hui Zhu
- State Key Laboratory of Agricultural Microbiology, Center of Integrative Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Deqiang Duanmu
- State Key Laboratory of Agricultural Microbiology, Center of Integrative Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yangrong Cao
- State Key Laboratory of Agricultural Microbiology, Center of Integrative Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhongming Zhang
- State Key Laboratory of Agricultural Microbiology, Center of Integrative Biology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
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Liu Y, Hassan S, Kidd BN, Garg G, Mathesius U, Singh KB, Anderson JP. Ethylene Signaling Is Important for Isoflavonoid-Mediated Resistance to Rhizoctonia solani in Roots of Medicago truncatula. Mol Plant Microbe Interact 2017; 30:691-700. [PMID: 28510484 DOI: 10.1094/mpmi-03-17-0057-r] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The root-infecting necrotrophic fungal pathogen Rhizoctoniasolani causes significant disease to all the world's major food crops. As a model for pathogenesis of legumes, we have examined the interaction of R. solani AG8 with Medicago truncatula. RNAseq analysis of the moderately resistant M. truncatula accession A17 and highly susceptible sickle (skl) mutant (defective in ethylene sensing) identified major early transcriptional reprogramming in A17. Responses specific to A17 included components of ethylene signaling, reactive oxygen species metabolism, and consistent upregulation of the isoflavonoid biosynthesis pathway. Mass spectrometry revealed accumulation of the isoflavonoid-related compounds liquiritigenin, formononetin, medicarpin, and biochanin A in A17. Overexpression of an isoflavone synthase in M. truncatula roots increased isoflavonoid accumulation and resistance to R. solani. Addition of exogenous medicarpin suggested this phytoalexin may be one of several isoflavonoids required to contribute to resistance to R. solani. Together, these results provide evidence for the role of ethylene-mediated accumulation of isoflavonoids during defense against root pathogens in legumes. The involvement of ethylene signaling and isoflavonoids in the regulation of both symbiont-legume and pathogen-legume interactions in the same tissue may suggest tight regulation of these responses are required in the root tissue.
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Affiliation(s)
- Yao Liu
- 1 CSIRO Agriculture and Food, Floreat, Western Australia
- 2 Rice Research Institute, Sichuan Agricultural University, Chengdu, China
| | - Samira Hassan
- 3 Research School of Biology, Australian National University, Canberra, Australian Capital Territory; and
| | - Brendan N Kidd
- 1 CSIRO Agriculture and Food, Floreat, Western Australia
| | - Gagan Garg
- 1 CSIRO Agriculture and Food, Floreat, Western Australia
| | - Ulrike Mathesius
- 3 Research School of Biology, Australian National University, Canberra, Australian Capital Territory; and
| | - Karam B Singh
- 1 CSIRO Agriculture and Food, Floreat, Western Australia
- 4 The UWA Institute of Agriculture, University of Western Australia, Crawley, Western Australia
| | - Jonathan P Anderson
- 1 CSIRO Agriculture and Food, Floreat, Western Australia
- 4 The UWA Institute of Agriculture, University of Western Australia, Crawley, Western Australia
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8
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Kamphuis LG, Guo SM, Gao LL, Singh KB. Genetic Mapping of a Major Resistance Gene to Pea Aphid (Acyrthosipon pisum) in the Model Legume Medicago truncatula. Int J Mol Sci 2016; 17:E1224. [PMID: 27483247 PMCID: PMC5000622 DOI: 10.3390/ijms17081224] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 07/20/2016] [Accepted: 07/22/2016] [Indexed: 01/05/2023] Open
Abstract
Resistance to the Australian pea aphid (PA; Acyrthosiphon pisum) biotype in cultivar Jester of the model legume Medicago truncatula is mediated by a single dominant gene and is phloem-mediated. The genetic map position for this resistance gene, APR (Acyrthosiphon pisum resistance), is provided and shows that APR maps 39 centiMorgans (cM) distal of the A. kondoi resistance (AKR) locus, which mediates resistance to a closely related species of the same genus bluegreen aphid (A. kondoi). The APR region on chromosome 3 is dense in classical nucleotide binding site leucine-rich repeats (NLRs) and overlaps with the region harbouring the RAP1 gene which confers resistance to a European PA biotype in the accession Jemalong A17. Further screening of a core collection of M. truncatula accessions identified seven lines with strong resistance to PA. Allelism experiments showed that the single dominant resistance to PA in M. truncatula accessions SA10481 and SA1516 are allelic to SA10733, the donor of the APR locus in cultivar Jester. While it remains unclear whether there are multiple PA resistance genes in an R-gene cluster or the resistance loci identified in the other M. truncatula accessions are allelic to APR, the introgression of APR into current M. truncatula cultivars will provide more durable resistance to PA.
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Affiliation(s)
- Lars G Kamphuis
- Commenwealth Scientific and Industrial Research Organisation, Agriculture and Food, 147 Underwood Avenue, Floreat, WA 6014, Australia.
- University of Western Australia Insititute of Agriculture, 35 Stirling Highway, Crawley, WA 6009, Australia.
| | - Su-Min Guo
- Commenwealth Scientific and Industrial Research Organisation, Agriculture and Food, 147 Underwood Avenue, Floreat, WA 6014, Australia.
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA.
| | - Ling-Ling Gao
- Commenwealth Scientific and Industrial Research Organisation, Agriculture and Food, 147 Underwood Avenue, Floreat, WA 6014, Australia.
| | - Karam B Singh
- Commenwealth Scientific and Industrial Research Organisation, Agriculture and Food, 147 Underwood Avenue, Floreat, WA 6014, Australia.
- University of Western Australia Insititute of Agriculture, 35 Stirling Highway, Crawley, WA 6009, Australia.
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9
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Paudel JR, Bede JC. Ethylene Signaling Modulates Herbivore-Induced Defense Responses in the Model Legume Medicago truncatula. Mol Plant Microbe Interact 2015; 28:569-79. [PMID: 25608182 DOI: 10.1094/mpmi-10-14-0348-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
One or more effectors in the labial saliva (LS) of generalist Noctuid caterpillars activate plant signaling pathways to modulate jasmonate (JA)-dependent defense responses; however, the exact mechanisms involved have yet to be elucidated. A potential candidate in this phytohormone interplay is the ethylene (ET) signaling pathway. We compared the biochemical and molecular responses of the model legume Medicago truncatula and the ET-insensitive skl mutant to herbivory by fourth instar Spodoptera exigua (Hübner) caterpillars with intact or impaired LS secretions. Cellular oxidative stress increases rapidly after herbivory, as evidenced by changes in oxidized-to-reduced ascorbate (ASC) and glutathione (GSH) ratios. The caterpillar-specific increase in GSH ratios and the LS-specific increase in ASC ratios are alleviated in the skl mutant, indicating that ET signaling is required. Ten hours postherbivory, markers of the JA and JA/ET pathways are differentially expressed; MtVSP is induced and MtHEL is repressed in a caterpillar LS- and ET-independent manner. In contrast, expression of the classic marker of the systemic acquired resistance pathway, MtPR1, is caterpillar LS-dependent and requires ET signaling. Caterpillar LS further suppresses the induction of JA-related trypsin inhibitor activity in an ET-dependent manner. Findings suggest that ET is involved in the caterpillar LS-dependent, salicylic acid/NPR1-mediated attenuation of JA-dependent induced responses.
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Affiliation(s)
- Jamuna Risal Paudel
- Department of Plant Science, McGill University, Ste-Anne-de-Bellevue, Qc, Canada, H9X 3V9, Canada
| | - Jacqueline C Bede
- Department of Plant Science, McGill University, Ste-Anne-de-Bellevue, Qc, Canada, H9X 3V9, Canada
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10
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Berrabah F, Ratet P, Gourion B. Multiple steps control immunity during the intracellular accommodation of rhizobia. J Exp Bot 2015; 66:1977-85. [PMID: 25682610 PMCID: PMC4378630 DOI: 10.1093/jxb/eru545] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 12/15/2014] [Accepted: 12/16/2014] [Indexed: 05/20/2023]
Abstract
Medicago truncatula belongs to the legume family and forms symbiotic associations with nitrogen fixing bacteria, the rhizobia. During these interactions, the plants develop root nodules in which bacteria invade the plant cells and fix nitrogen for the benefit of the plant. Despite massive infection, legume nodules do not develop visible defence reactions, suggesting a special immune status of these organs. Some factors influencing rhizobium maintenance within the plant cells have been previously identified, such as the M. truncatula NCR peptides whose toxic effects are reduced by the bacterial protein BacA. In addition, DNF2, SymCRK, and RSD are M. truncatula genes required to avoid rhizobial death within the symbiotic cells. DNF2 and SymCRK are essential to prevent defence-like reactions in nodules after bacteria internalization into the symbiotic cells. Herein, we used a combination of genetics, histology and molecular biology approaches to investigate the relationship between the factors preventing bacterial death in the nodule cells. We show that the RSD gene is also required to repress plant defences in nodules. Upon inoculation with the bacA mutant, defence responses are observed only in the dnf2 mutant and not in the symCRK and rsd mutants. In addition, our data suggest that lack of nitrogen fixation by the bacterial partner triggers bacterial death in nodule cells after bacteroid differentiation. Together our data indicate that, after internalization, at least four independent mechanisms prevent bacterial death in the plant cell. These mechanisms involve successively: DNF2, BacA, SymCRK/RSD and bacterial ability to fix nitrogen.
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Affiliation(s)
- Fathi Berrabah
- Institut des Sciences du Végétal, CNRS, Saclay Plant Sciences, Avenue de la Terrasse, 91198 Gif sur Yvette, France
| | - Pascal Ratet
- Institut des Sciences du Végétal, CNRS, Saclay Plant Sciences, Avenue de la Terrasse, 91198 Gif sur Yvette, France
| | - Benjamin Gourion
- Institut des Sciences du Végétal, CNRS, Saclay Plant Sciences, Avenue de la Terrasse, 91198 Gif sur Yvette, France
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Truong HN, Thalineau E, Bonneau L, Fournier C, Potin S, Balzergue S, VAN Tuinen D, Jeandroz S, Morandi D. The Medicago truncatula hypermycorrhizal B9 mutant displays an altered response to phosphate and is more susceptible to Aphanomyces euteiches. Plant Cell Environ 2015; 38:73-88. [PMID: 24815324 DOI: 10.1111/pce.12370] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/29/2014] [Accepted: 04/30/2014] [Indexed: 05/13/2023]
Abstract
Inorganic phosphate (Pi) plays a key role in the development of arbuscular mycorrhizal (AM) symbiosis, which is favoured when Pi is limiting in the environment. We have characterized the Medicago truncatula hypermycorrhizal B9 mutant for its response to limiting (P/10) and replete (P2) Pi. On P2, mycorrhization was significantly higher in B9 plants than in wild-type (WT). The B9 mutant displayed hallmarks of Pi-limited plants, including higher levels of anthocyanins and lower concentrations of Pi in shoots than WT plants. Transcriptome analyses of roots of WT and B9 plants cultivated on P2 or on P/10 confirmed the Pi-limited profile of the mutant on P2 and highlighted its altered response to Pi on P/10. Furthermore, the B9 mutant displayed a higher expression of defence/stress-related genes and was more susceptible to infection by the root oomycete pathogen Aphanomyces euteiches than WT plants. We propose that the hypermycorrhizal phenotype of the B9 mutant is linked to its Pi-limited status favouring AM symbiosis in contrast to WT plants in Pi-replete conditions, and discuss the possible links between the altered response of the B9 mutant to Pi, mycorrhization and infection by A. euteiches.
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Affiliation(s)
- Hoai-Nam Truong
- INRA/AgroSup/Université de Bourgogne UMR1347 Agroécologie, ERL CNRS 6300, Dijon, F-21065, France
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12
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Berrabah F, Bourcy M, Eschstruth A, Cayrel A, Guefrachi I, Mergaert P, Wen J, Jean V, Mysore KS, Gourion B, Ratet P. A nonRD receptor-like kinase prevents nodule early senescence and defense-like reactions during symbiosis. New Phytol 2014; 203:1305-1314. [PMID: 24916161 DOI: 10.1111/nph.12881] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 04/30/2014] [Indexed: 05/11/2023]
Abstract
Rhizobia and legumes establish symbiotic interactions leading to the production of root nodules, in which bacteria fix atmospheric nitrogen for the plant's benefit. This symbiosis is efficient because of the high rhizobia population within nodules. Here, we investigated how legumes accommodate such bacterial colonization. We used a reverse genetic approach to identify a Medicago truncatula gene, SymCRK, which encodes a cysteine-rich receptor-like kinase that is required for rhizobia maintenance within the plant cells, and performed detailed phenotypic analyses of the corresponding mutant. The Medicago truncatula symCRK mutant developed nonfunctional and necrotic nodules. A nonarginine asparate (nonRD) motif, typical of receptors involved in innate immunity, is present in the SymCRK kinase domain. Similar to the dnf2 mutant, bacteroid differentiation defect, defense-like reactions and early senescence were observed in the symCRK nodules. However, the dnf2 and symCRK nodules differ by their degree of colonization, which is higher in symCRK. Furthermore, in contrast to dnf2, symCRK is not a conditional mutant. These results suggest that in M. truncatula at least two genes are involved in the symbiotic control of immunity. Furthermore, phenotype differences between the two mutants suggest that two distinct molecular mechanisms control suppression of plant immunity during nodulation.
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Affiliation(s)
- Fathi Berrabah
- Institut des sciences du végétal, CNRS, Saclay Plant Sciences, Avenue de la terrasse, 91198, Gif Sur Yvette, France
| | - Marie Bourcy
- Institut des sciences du végétal, CNRS, Saclay Plant Sciences, Avenue de la terrasse, 91198, Gif Sur Yvette, France
| | - Alexis Eschstruth
- Institut des sciences du végétal, CNRS, Saclay Plant Sciences, Avenue de la terrasse, 91198, Gif Sur Yvette, France
| | - Anne Cayrel
- Institut des sciences du végétal, CNRS, Saclay Plant Sciences, Avenue de la terrasse, 91198, Gif Sur Yvette, France
| | - Ibtissem Guefrachi
- Institut des sciences du végétal, CNRS, Saclay Plant Sciences, Avenue de la terrasse, 91198, Gif Sur Yvette, France
| | - Peter Mergaert
- Institut des sciences du végétal, CNRS, Saclay Plant Sciences, Avenue de la terrasse, 91198, Gif Sur Yvette, France
| | - Jiangqi Wen
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Viviane Jean
- Institut des sciences du végétal, CNRS, Saclay Plant Sciences, Avenue de la terrasse, 91198, Gif Sur Yvette, France
| | - Kirankumar S Mysore
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Benjamin Gourion
- Institut des sciences du végétal, CNRS, Saclay Plant Sciences, Avenue de la terrasse, 91198, Gif Sur Yvette, France
| | - Pascal Ratet
- Institut des sciences du végétal, CNRS, Saclay Plant Sciences, Avenue de la terrasse, 91198, Gif Sur Yvette, France
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Bonhomme M, André O, Badis Y, Ronfort J, Burgarella C, Chantret N, Prosperi JM, Briskine R, Mudge J, Debéllé F, Navier H, Miteul H, Hajri A, Baranger A, Tiffin P, Dumas B, Pilet-Nayel ML, Young ND, Jacquet C. High-density genome-wide association mapping implicates an F-box encoding gene in Medicago truncatula resistance to Aphanomyces euteiches. New Phytol 2014; 201:1328-1342. [PMID: 24283472 DOI: 10.1111/nph.12611] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 10/23/2013] [Indexed: 05/18/2023]
Abstract
• The use of quantitative disease resistance (QDR) is a promising strategy for promoting durable resistance to plant pathogens, but genes involved in QDR are largely unknown. To identify genetic components and accelerate improvement of QDR in legumes to the root pathogen Aphanomyces euteiches, we took advantage of both the recently generated massive genomic data for Medicago truncatula and natural variation of this model legume. • A high-density (≈5.1 million single nucleotide polymorphisms (SNPs)) genome-wide association study (GWAS) was performed with both in vitro and glasshouse phenotyping data collected for 179 lines. • GWAS identified several candidate genes and pinpointed two independent major loci on the top of chromosome 3 that were detected in both phenotyping methods. Candidate SNPs in the most significant locus (σ(A)²= 23%) were in the promoter and coding regions of an F-box protein coding gene. Subsequent qRT-PCR and bioinformatic analyses performed on 20 lines demonstrated that resistance is associated with mutations directly affecting the interaction domain of the F-box protein rather than gene expression. • These results refine the position of previously identified QTL to specific candidate genes, suggest potential molecular mechanisms, and identify new loci explaining QDR against A. euteiches.
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Affiliation(s)
- Maxime Bonhomme
- UPS, Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire de Recherche en Sciences Végétales, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
| | - Olivier André
- UPS, Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire de Recherche en Sciences Végétales, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
| | - Yacine Badis
- UPS, Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire de Recherche en Sciences Végétales, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
| | | | | | | | | | - Roman Briskine
- Department of Computer Science and Engineering, University of Minnesota, Saint-Paul, MN, 55455, USA
| | - Joann Mudge
- National Center for Genome Resources, 2935 Rodeo Park Drive East, Santa Fe, NM, 87505, USA
| | - Frédéric Debéllé
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326, Castanet-Tolosan, France
| | - Hélène Navier
- INRA, UMR 1349 IGEPP, F-35653, Le Rheu Cedex, France
| | - Henri Miteul
- INRA, UMR 1349 IGEPP, F-35653, Le Rheu Cedex, France
| | - Ahmed Hajri
- INRA, UMR 1349 IGEPP, F-35653, Le Rheu Cedex, France
| | | | - Peter Tiffin
- Department of Plant Biology, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Bernard Dumas
- UPS, Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire de Recherche en Sciences Végétales, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
| | | | - Nevin D Young
- Department of Plant Biology, University of Minnesota, Saint Paul, MN, 55108, USA
- Department of Plant Pathology, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Christophe Jacquet
- UPS, Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
- CNRS, Laboratoire de Recherche en Sciences Végétales, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
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14
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Kamphuis LG, Lichtenzveig J, Peng K, Guo SM, Klingler JP, Siddique KHM, Gao LL, Singh KB. Characterization and genetic dissection of resistance to spotted alfalfa aphid (Therioaphis trifolii) in Medicago truncatula. J Exp Bot 2013; 64:5157-72. [PMID: 24058162 PMCID: PMC3830491 DOI: 10.1093/jxb/ert305] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Aphids cause significant yield losses in agricultural crops worldwide. Medicago truncatula, a model legume, cultivated pasture species in Australia and close relative of alfalfa (Medicago sativa), was used to study the defence response against Therioaphis trifolii f. maculate [spotted alfalfa aphid (SAA)]. Aphid performance and plant damage were compared among three accessions. A20 is highly susceptible, A17 has moderate resistance, and Jester is strongly resistant. Subsequent analyses using A17 and A20, reciprocal F1s and an A17×A20 recombinant inbred line (RIL) population revealed that this moderate resistance is phloem mediated and involves antibiosis and tolerance but not antixenosis. Electrical penetration graph analysis also identified a novel waveform termed extended potential drop, which occurred following SAA infestation of M. truncatula. Genetic dissection using the RIL population revealed three quantitative trait loci on chromosomes 3, 6, and 7 involved in distinct modes of aphid defence including antibiosis and tolerance. An antibiosis locus resides on linkage group 3 (LG3) and is derived from A17, whereas a plant tolerance and antibiosis locus resides on LG6 and is derived from A20, which exhibits strong temporary tolerance. The loci identified reside in regions harbouring classical resistance genes, and introgression of these loci in current medic cultivars may help provide durable resistance to SAA, while elucidation of their molecular mechanisms may provide valuable insight into other aphid-plant interactions.
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Affiliation(s)
- Lars G Kamphuis
- CSIRO Plant Industry, Private Bag 5, Wembley, WA 6913, Australia
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Gough C, Jacquet C. Nod factor perception protein carries weight in biotic interactions. Trends Plant Sci 2013; 18:566-74. [PMID: 23850222 DOI: 10.1016/j.tplants.2013.06.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 06/04/2013] [Accepted: 06/13/2013] [Indexed: 05/10/2023]
Abstract
Plant plasma membrane-bound receptors with extracellular lysin motif (LysM) domains participate in interactions with microorganisms. In Medicago truncatula, the LysM receptor-like kinase gene nodulation (Nod) factor perception (NFP) is a key gene that controls the perception of rhizobial lipochitooligosaccharide (LCO) Nod factors for the establishment of the Rhizobium-legume symbiosis. In this article, we review recent data that have refined our understanding of this function and that have revealed a role for NFP in the perception of arbuscular mycorrhizal (AM) symbiotic signals and plant pathogenic microorganisms. The dual role of NFP in symbiosis and immunity suggests that this receptor protein controls the perception of different signals and the activation of different downstream signalling pathways. These advances provide new insights into the evolution and functioning of this versatile plant protein.
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Affiliation(s)
- Clare Gough
- Institut National de la Recherche Agronomique, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326 Castanet-Tolosan, France; Centre National de la Recherche Scientifique (CNRS), Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326 Castanet-Tolosan, France.
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Ben C, Debellé F, Berges H, Bellec A, Jardinaud MF, Anson P, Huguet T, Gentzbittel L, Vailleau F. MtQRRS1, an R-locus required for Medicago truncatula quantitative resistance to Ralstonia solanacearum. New Phytol 2013; 199:758-72. [PMID: 23638965 DOI: 10.1111/nph.12299] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 03/27/2013] [Indexed: 05/21/2023]
Abstract
Ralstonia solanacearum is a major soilborne pathogen that attacks > 200 plant species, including major crops. To characterize MtQRRS1, a major quantitative trait locus (QTL) for resistance towards this bacterium in the model legume Medicago truncatula, genetic and functional approaches were combined. QTL analyses together with disease scoring of heterogeneous inbred families were used to define the locus. The candidate region was studied by physical mapping using a bacterial artificial chromosome (BAC) library of the resistant line, and sequencing. In planta bacterial growth measurements, grafting experiments and gene expression analysis were performed to investigate the mechanisms by which this locus confers resistance to R. solanacearum. The MtQRRS1 locus was localized to the same position in two recombinant inbred line populations and was narrowed down to a 64 kb region. Comparison of parental line sequences revealed 15 candidate genes with sequence polymorphisms, but no evidence of differential gene expression upon infection. A role for the hypocotyl in resistance establishment was shown. These data indicate that the quantitative resistance to bacterial wilt conferred by MtQRRS1, which contains a cluster of seven R genes, is shared by different accessions and may act through intralocus interactions to promote resistance.
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Affiliation(s)
- Cécile Ben
- INP, UPS, Laboratoire d'Ecologie Fonctionnelle et Environnement (Ecolab), ENSAT, Université de Toulouse, Castanet Tolosan, France
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Banasiak J, Biala W, Staszków A, Swarcewicz B, Kepczynska E, Figlerowicz M, Jasinski M. A Medicago truncatula ABC transporter belonging to subfamily G modulates the level of isoflavonoids. J Exp Bot 2013; 64:1005-15. [PMID: 23314816 DOI: 10.1093/jxb/ers380] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Full-sized ATP-binding cassette (ABC) transporters of the G subfamily (ABCG) are considered to be essential components of the plant immune system. These proteins have been proposed to be implicated in the active transmembrane transport of various secondary metabolites. Despite the importance of ABCG-based transport for plant-microbe interactions, these proteins are still poorly recognized in legumes. The experiments described here demonstrated that the level of Medicago truncatula ABCG10 (MtABCG10) mRNA was elevated following application of fungal oligosaccharides to plant roots. Spatial expression pattern analysis with a reporter gene revealed that the MtABCG10 promoter was active in various organs, mostly within their vascular tissues. The corresponding protein was located in the plasma membrane. Silencing of MtABCG10 in hairy roots resulted in lower accumulation of the phenylpropanoid pathway-derived medicarpin and its precursors. PCR-based experiments indicated that infection with Fusarium oxysporum, a root-infecting pathogen, progressed faster in MtABCG10-silenced composite plants (consisting of wild-type shoots on transgenic roots) than in the corresponding controls. Based on the presented data, it is proposed that in Medicago, full-sized ABCG transporters might modulate isoflavonoid levels during the defence response associated with de novo synthesis of phytoalexins.
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Affiliation(s)
- Joanna Banasiak
- Institute of Bioorganic Chemistry PAS, Noskowskiego 12/14, Poznań, Poland
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Ben C, Toueni M, Montanari S, Tardin MC, Fervel M, Negahi A, Saint-Pierre L, Mathieu G, Gras MC, Noël D, Prospéri JM, Pilet-Nayel ML, Baranger A, Huguet T, Julier B, Rickauer M, Gentzbittel L. Natural diversity in the model legume Medicago truncatula allows identifying distinct genetic mechanisms conferring partial resistance to Verticillium wilt. J Exp Bot 2013; 64:317-32. [PMID: 23213135 PMCID: PMC3528038 DOI: 10.1093/jxb/ers337] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Verticillium wilt is a major threat to alfalfa (Medicago sativa) and many other crops. The model legume Medicago truncatula was used as a host for studying resistance and susceptibility to Verticillium albo-atrum. In addition to presenting well-established genetic resources, this wild plant species enables to investigate biodiversity of the response to the pathogen and putative crosstalk between disease and symbiosis. Symptom scoring after root inoculation and modelling of disease curves allowed assessing susceptibility levels in recombinant lines of three crosses between susceptible and resistant lines, in a core collection of 32 lines, and in mutants affected in symbiosis with rhizobia. A GFP-expressing V. albo-atrum strain was used to study colonization of susceptible plants. Symptoms and colonization pattern in infected M. truncatula plants were typical of Verticillium wilt. Three distinct major quantitative trait loci were identified using a multicross, multisite design, suggesting that simple genetic mechanisms appear to control Verticillium wilt resistance in M. truncatula lines A17 and DZA45.5. The disease functional parameters varied largely in lines of the core collection. This biodiversity with regard to disease response encourages the development of association genetics and ecological approaches. Several mutants of the resistant line, impaired in different steps of rhizobial symbiosis, were affected in their response to V. albo-atrum, which suggests that mechanisms involved in the establishment of symbiosis or disease might have some common regulatory control points.
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Affiliation(s)
- Cécile Ben
- Université de Toulouse; INP, UPS; Laboratoire d’Écologie Fonctionnelle et Environnement (EcoLab); ENSAT, 18 chemin de Borderouge, 31326 Castanet Tolosan, France
- CNRS; EcoLab; 31326 Castanet Tolosan, France
| | - Maoulida Toueni
- Université de Toulouse; INP, UPS; Laboratoire d’Écologie Fonctionnelle et Environnement (EcoLab); ENSAT, 18 chemin de Borderouge, 31326 Castanet Tolosan, France
- CNRS; EcoLab; 31326 Castanet Tolosan, France
| | - Sara Montanari
- Université de Toulouse; INP, UPS; Laboratoire d’Écologie Fonctionnelle et Environnement (EcoLab); ENSAT, 18 chemin de Borderouge, 31326 Castanet Tolosan, France
| | | | - Magalie Fervel
- Barenbrug Tourneur Recherches, Negadis, 82600 Mas Grenier, France
| | - Azam Negahi
- Université de Toulouse; INP, UPS; Laboratoire d’Écologie Fonctionnelle et Environnement (EcoLab); ENSAT, 18 chemin de Borderouge, 31326 Castanet Tolosan, France
- CNRS; EcoLab; 31326 Castanet Tolosan, France
| | | | - Guillaume Mathieu
- Université de Toulouse; INP, UPS; Laboratoire d’Écologie Fonctionnelle et Environnement (EcoLab); ENSAT, 18 chemin de Borderouge, 31326 Castanet Tolosan, France
| | | | - Dominique Noël
- Barenbrug Tourneur Recherches, Negadis, 82600 Mas Grenier, France
| | | | - Marie-Laure Pilet-Nayel
- INRA, Agrocampus Ouest, Université de Rennes1, UMR118, Amélioration des Plantes et Biotechnologies Végétales, 35653 Le Rheu Cedex, Rennes, France
| | - Alain Baranger
- INRA, Agrocampus Ouest, Université de Rennes1, UMR118, Amélioration des Plantes et Biotechnologies Végétales, 35653 Le Rheu Cedex, Rennes, France
| | - Thierry Huguet
- Université de Toulouse; INP, UPS; Laboratoire d’Écologie Fonctionnelle et Environnement (EcoLab); ENSAT, 18 chemin de Borderouge, 31326 Castanet Tolosan, France
- CNRS; EcoLab; 31326 Castanet Tolosan, France
| | - Bernadette Julier
- INRA, UR 4, Unité de Recherche Pluridisciplinaire Prairies et Plantes Fourragères, Le Chêne, RD 150, BP 80006, 86600, Lusignan, France
| | - Martina Rickauer
- Université de Toulouse; INP, UPS; Laboratoire d’Écologie Fonctionnelle et Environnement (EcoLab); ENSAT, 18 chemin de Borderouge, 31326 Castanet Tolosan, France
- CNRS; EcoLab; 31326 Castanet Tolosan, France
| | - Laurent Gentzbittel
- Université de Toulouse; INP, UPS; Laboratoire d’Écologie Fonctionnelle et Environnement (EcoLab); ENSAT, 18 chemin de Borderouge, 31326 Castanet Tolosan, France
- CNRS; EcoLab; 31326 Castanet Tolosan, France
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Kamphuis LG, Gao L, Singh KB. Identification and characterization of resistance to cowpea aphid (Aphis craccivora Koch) in Medicago truncatula. BMC Plant Biol 2012; 12:101. [PMID: 22759788 PMCID: PMC3464659 DOI: 10.1186/1471-2229-12-101] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 06/25/2012] [Indexed: 05/21/2023]
Abstract
BACKGROUND Cowpea aphid (CPA; Aphis craccivora) is the most important insect pest of cowpea and also causes significant yield losses in other legume crops including alfalfa, beans, chickpea, lentils, lupins and peanuts. In many of these crops there is no natural genetic resistance to this sap-sucking insect or resistance genes have been overcome by newly emerged CPA biotypes. RESULTS In this study, we screened a subset of the Medicago truncatula core collection of the South Australian Research and Development Institute (SARDI) and identified strong resistance to CPA in a M. truncatula accession SA30199, compared to all other M. truncatula accessions tested. The biology of resistance to CPA in SA30199 plants was characterised compared to the highly susceptible accession Borung and showed that resistance occurred at the level of the phloem, required an intact plant and involved a combination of antixenosis and antibiosis. Quantitative trait loci (QTL) analysis using a F2 population (n = 150) from a cross between SA30199 and Borung revealed that resistance to CPA is controlled in part by a major quantitative trait locus (QTL) on chromosome 2, explaining 39% of the antibiosis resistance. CONCLUSIONS The identification of strong CPA resistance in M. truncatula allows for the identification of key regulators and genes important in this model legume to give effective CPA resistance that may have relevance for other legume crops. The identified locus will also facilitate marker assisted breeding of M. truncatula for increased resistance to CPA and potentially other closely related Medicago species such as alfalfa.
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Affiliation(s)
- Lars G Kamphuis
- CSIRO Plant Industry, Private Bag 5, Wembley, WA, 6913, Australia
- The UWA Institute of Agriculture, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Lingling Gao
- CSIRO Plant Industry, Private Bag 5, Wembley, WA, 6913, Australia
| | - Karam B Singh
- CSIRO Plant Industry, Private Bag 5, Wembley, WA, 6913, Australia
- The UWA Institute of Agriculture, The University of Western Australia, Crawley, WA, 6009, Australia
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Guo SM, Kamphuis LG, Gao LL, Klingler JP, Lichtenzveig J, Edwards O, Singh KB. Identification of distinct quantitative trait loci associated with defence against the closely related aphids Acyrthosiphon pisum and A. kondoi in Medicago truncatula. J Exp Bot 2012; 63:3913-22. [PMID: 22442407 PMCID: PMC3388833 DOI: 10.1093/jxb/ers084] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Aphids are a major family of plant insect pests. Medicago truncatula and Acyrthosiphon pisum (pea aphid, PA) are model species with a suite of resources available to help dissect the mechanism underlying plant-aphid interactions. A previous study focused on monogenic and relatively strong resistance in M. truncatula to PA and other aphid species. In this study a moderate resistance to PA was characterized in detail in the M. truncatula line A17 and compared with the highly susceptible line A20 and the more resistant line Jester. The results show that PA resistance in A17 involves both antibiosis and tolerance, and that resistance is phloem based. Quantitative trait locus (QTL) analysis using a recombinant inbred line (RIL) population (n=114) from a cross between A17 and A20 revealed that one locus, which co-segregated with AIN (Acyrthosiphon-induced necrosis) on chromosome 3, is responsible for the reduction of aphid biomass (indicator of antibiosis) for both PA and bluegreen aphid (BGA, A. kondoi), albeit to a lesser degree for PA than BGA. Interestingly, two independent loci on chromosomes 5 and 3 were identified for the plant biomass reduction (indicator of plant tolerance) by PA and BGA, respectively, demonstrating that the plant's tolerance response to these two closely related aphid species is distinct. Together with previously identified major resistant (R) genes, the QTLs identified in this study are powerful tools to understand fully the spectrum of plant defence against sap-sucking insects and provide opportunities for breeders to generate effective and sustainable strategies for aphid control.
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Affiliation(s)
- Su-Min Guo
- Key Laboratory of Genetics & Biotechnology, Ministry of Education, Nanjing Forestry University, Nanjing 210037, China
- CSIRO Plant Industry, Private Bag 5, Wembley, WA 6913, Australia
| | - Lars G. Kamphuis
- CSIRO Plant Industry, Private Bag 5, Wembley, WA 6913, Australia
- The UWA Institute of Agriculture, University of Western Australia, Crawley, WA 6009, Australia
| | - Ling-Ling Gao
- CSIRO Plant Industry, Private Bag 5, Wembley, WA 6913, Australia
| | - John P. Klingler
- CSIRO Plant Industry, Private Bag 5, Wembley, WA 6913, Australia
- CSIRO Entomology, Private Bag 5, Wembley, WA 6913, Australia
| | - Judith Lichtenzveig
- CSIRO Plant Industry, Private Bag 5, Wembley, WA 6913, Australia
- Australian Centre for Necrotrophic Fungal Pathogens, Department of Environment and Agriculture, Curtin University, Bentley, WA 6102, Australia
| | - Owain Edwards
- CSIRO Entomology, Private Bag 5, Wembley, WA 6913, Australia
- CSIRO Ecosystem Sciences, Private Bag 5, Wembley, WA 6913, Australia
| | - Karam B. Singh
- CSIRO Plant Industry, Private Bag 5, Wembley, WA 6913, Australia
- The UWA Institute of Agriculture, University of Western Australia, Crawley, WA 6009, Australia
- To whom correspondence should be addressed. E-mail:
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Selim S, Negrel J, Wendehenne D, Ochatt S, Gianinazzi S, van Tuinen D. Stimulation of defense reactions in Medicago truncatula by antagonistic lipopeptides from Paenibacillus sp. strain B2. Appl Environ Microbiol 2010. [PMID: 20870792 DOI: 10.1128/aem.00171-110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023] Open
Abstract
With the aim of obtaining new strategies to control plant diseases, we investigated the ability of antagonistic lipopolypeptides (paenimyxin) from Paenibacillus sp. strain B2 to elicit hydrogen peroxide (H₂O₂) production and several defense-related genes in the model legume Medicago truncatula. For this purpose, M. truncatula cell suspensions were used and a pathosystem between M. truncatula and Fusarium acuminatum was established. In M. truncatula cell cultures, the induction of H₂O₂ reached a maximum 20 min after elicitation with paenimyxin, whereas concentrations higher than 20 μM inhibited H₂O₂ induction and this was correlated with a lethal effect. In plant roots incubated with different concentrations of paenimyxin for 24 h before inoculation with F. acuminatum, paenimyxin at a low concentration (ca. 1 μM) had a protective effect and suppressed 95% of the necrotic symptoms, whereas a concentration higher than 10 μM had an inhibitory effect on plant growth. Gene responses were quantified in M. truncatula by semiquantitative reverse transcription-PCR (RT-PCR). Genes involved in the biosynthesis of phytoalexins (phenylalanine ammonia-lyase, chalcone synthase, chalcone reductase), antifungal activity (pathogenesis-related proteins, chitinase), or cell wall (invertase) were highly upregulated in roots or cells after paenimyxin treatment. The mechanisms potentially involved in plant protection are discussed.
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Affiliation(s)
- Sameh Selim
- UMR INRA 1088, CNRS 5184, Université de Bourgogne Plante-Microbe-Environnement CMSE-INRA, 17 Rue Sully, BP 86510, 21065 Dijon Cedex, France
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22
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Anderson JP, Lichtenzveig J, Gleason C, Oliver RP, Singh KB. The B-3 ethylene response factor MtERF1-1 mediates resistance to a subset of root pathogens in Medicago truncatula without adversely affecting symbiosis with rhizobia. Plant Physiol 2010; 154:861-73. [PMID: 20713618 PMCID: PMC2949043 DOI: 10.1104/pp.110.163949] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Accepted: 08/13/2010] [Indexed: 05/20/2023]
Abstract
The fungal necrotrophic pathogen Rhizoctonia solani is a significant constraint to a range of crops as diverse as cereals, canola, and legumes. Despite wide-ranging germplasm screens in many of these crops, no strong genetic resistance has been identified, suggesting that alternative strategies to improve resistance are required. In this study, we characterize moderate resistance to R. solani anastomosis group 8 identified in Medicago truncatula. The activity of the ethylene- and jasmonate-responsive GCC box promoter element was associated with moderate resistance, as was the induction of the B-3 subgroup of ethylene response transcription factors (ERFs). Genes of the B-1 subgroup showed no significant response to R. solani infection. Overexpression of a B-3 ERF, MtERF1-1, in Medicago roots increased resistance to R. solani as well as an oomycete root pathogen, Phytophthora medicaginis, but not root knot nematode. These results indicate that targeting specific regulators of ethylene defense may enhance resistance to an important subset of root pathogens. We also demonstrate that overexpression of MtERF1-1 enhances disease resistance without apparent impact on nodulation in the A17 background, while overexpression in sickle reduced the hypernodulation phenotype. This suggests that under normal regulation of nodulation, enhanced resistance to root diseases can be uncoupled from symbiotic plant-microbe interactions in the same tissue and that ethylene/ERF regulation of nodule number is distinct from the defenses regulated by B-3 ERFs. Furthermore, unlike the stunted phenotype previously described for Arabidopsis (Arabidopsis thaliana) ubiquitously overexpressing B-3 ERFs, overexpression of MtERF1-1 in M. truncatula roots did not show adverse effects on plant development.
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23
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Hamon C, Baranger A, Miteul H, Lecointe R, Le Goff I, Deniot G, Onfroy C, Moussart A, Prosperi JM, Tivoli B, Delourme R, Pilet-Nayel ML. A complex genetic network involving a broad-spectrum locus and strain-specific loci controls resistance to different pathotypes of Aphanomyces euteiches in Medicago truncatula. Theor Appl Genet 2010; 120:955-70. [PMID: 20012740 DOI: 10.1007/s00122-009-1224-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Accepted: 11/12/2009] [Indexed: 05/03/2023]
Abstract
A higher understanding of genetic and genomic bases of partial resistance in plants and their diversity regarding pathogen variability is required for a more durable management of resistance genetic factors in sustainable cropping systems. In this study, we investigated the diversity of genetic factors involved in partial resistance to Aphanomyces euteiches, a very damaging pathogen on pea and alfalfa, in Medicago truncatula. A mapping population of 178 recombinant inbred lines, from the cross F83005.5 (susceptible) and DZA045.5 (resistant), was used to identify quantitative trait loci for resistance to four A. euteiches reference strains belonging to the four main pathotypes currently known on pea and alfalfa. A major broad-spectrum genomic region, previously named AER1, was localized to a reduced 440 kb interval on chromosome 3 and was involved in complete or partial resistance, depending on the A. euteiches strain. We also identified 21 additive and/or epistatic genomic regions specific to one or two strains, several of them being anchored to the M. truncatula physical map. These results show that, in M. truncatula, a complex network of genetic loci controls partial resistance to different pea and alfalfa pathotypes of A. euteiches, suggesting a diversity of molecular mechanisms underlying partial resistance.
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Affiliation(s)
- Céline Hamon
- INRA, Agrocampus Ouest, Université de Rennes 1, UMR118, Amélioration des Plantes et Biotechnologies Végétales, 35653, Le Rheu Cedex, Rennes, France.
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24
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Klingler JP, Nair RM, Edwards OR, Singh KB. A single gene, AIN, in Medicago truncatula mediates a hypersensitive response to both bluegreen aphid and pea aphid, but confers resistance only to bluegreen aphid. J Exp Bot 2009; 60:4115-27. [PMID: 19690018 PMCID: PMC2755030 DOI: 10.1093/jxb/erp244] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Revised: 07/11/2009] [Accepted: 07/15/2009] [Indexed: 05/03/2023]
Abstract
Biotic stress in plants frequently induces a hypersensitive response (HR). This distinctive reaction has been studied intensively in several pathosystems and has shed light on the biology of defence signalling. Compared with microbial pathogens, relatively little is known about the role of the HR in defence against insects. Reference genotype A17 of Medicago truncatula Gaertn., a model legume, responds to aphids of the genus Acyrthosiphon with necrotic lesions resembling a HR. In this study, the biochemical nature of this response, its mode of inheritance, and its relationship with defence against aphids were investigated. The necrotic lesion phenotype and resistance to the bluegreen aphid (BGA, Acyrthosiphon kondoi Shinji) and the pea aphid (PA, Acyrthosiphon pisum (Harris)) were analysed using reference genotypes A17 and A20, their F(2) progeny and recombinant inbred lines. BGA-induced necrotic lesions co-localized with the production of H(2)O(2), consistent with an oxidative burst widely associated with hypersensitivity. This HR correlated with stronger resistance to BGA in A17 than in A20; these phenotypes cosegregated as a semi-dominant gene, AIN (Acyrthosiphon-induced necrosis). In contrast to BGA, stronger resistance to PA in A17, compared with A20, did not cosegregate with a PA-induced HR. The AIN locus resides in a cluster of sequences predicted to encode the CC-NBS-LRR subfamily of resistance proteins. AIN-mediated resistance presents a novel opportunity to use a model plant and model aphid to study the role of the HR in defence responses to phloem-feeding insects.
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Affiliation(s)
- John P Klingler
- Commonwealth Scientific and Industrial Research Organisation Entomology, Private Bag 5, Wembley, WA 6913, Australia.
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25
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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26
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Ameline-Torregrosa C, Cazaux M, Danesh D, Chardon F, Cannon SB, Esquerré-Tugayé MT, Dumas B, Young ND, Samac DA, Huguet T, Jacquet C. Genetic dissection of resistance to anthracnose and powdery mildew in Medicago truncatula. Mol Plant Microbe Interact 2008; 21:61-9. [PMID: 18052883 DOI: 10.1094/mpmi-21-1-0061] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Medicago truncatula was used to characterize resistance to anthracnose and powdery mildew caused by Colletotrichum trifolii and Erysiphe pisi, respectively. Two isolates of E. pisi (Ep-p from pea and Ep-a from alfalfa) and two races of C. trifolii (races 1 and 2) were used in this study. The A17 genotype was resistant and displayed a hypersensitive response after inoculation with either pathogen, while lines F83005.5 and DZA315.16 were susceptible to anthracnose and powdery mildew, respectively. To identify the genetic determinants underlying resistance in A17, two F7 recombinant inbred line (RIL) populations, LR4 (A17 x DZA315.16) and LR5 (A17 x F83005.5), were phenotyped with E. pisi isolates and C. trifolii races, respectively. Genetic analyses showed that i) resistance to anthracnose is governed mainly by a single major locus to both races, named Ct1 and located on the upper part of chromosome 4; and ii) resistance to powdery mildew involves three distinct loci, Epp1 on chromosome 4 and Epa1 and Epa2 on chromosome 5. The use of a consensus genetic map for the two RIL populations revealed that Ct1 and Epp1, although located in the same genome region, were clearly distinct. In silico analysis in this region identified the presence of several clusters of nucleotide binding site leucine-rich repeat genes. Many of these genes have atypical resistance gene analog structures and display differential expression patterns in distinct stress-related cDNA libraries.
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Affiliation(s)
- Carine Ameline-Torregrosa
- UMR 5546, Centre National de la Recherche Scientifique-UPS, Pôle de Biotechnologie Végétale, 24 Chemin Borde Rouge, 34326 Castanet-Tolosan, France
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27
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Liu J, Maldonado-Mendoza I, Lopez-Meyer M, Cheung F, Town CD, Harrison MJ. Arbuscular mycorrhizal symbiosis is accompanied by local and systemic alterations in gene expression and an increase in disease resistance in the shoots. Plant J 2007; 50:529-44. [PMID: 17419842 DOI: 10.1111/j.1365-313x.2007.03069.x] [Citation(s) in RCA: 241] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
In natural ecosystems, the roots of many plants exist in association with arbuscular mycorrhizal (AM) fungi, and the resulting symbiosis has profound effects on the plant. The most frequently documented response is an increase in phosphorus nutrition; however, other effects have been noted, including increased resistance to abiotic and biotic stresses. Here we used a 16,000-feature oligonucleotide array and real-time quantitative RT-PCR to explore transcriptional changes triggered in Medicago truncatula roots and shoots as a result of AM symbiosis. By controlling the experimental conditions, phosphorus-related effects were minimized, and both local and systemic transcriptional responses to the AM fungus were revealed. The transcriptional response of the roots and shoots differed in both the magnitude of gene induction and the predicted functional categories of the mycorrhiza-regulated genes. In the roots, genes regulated in response to three different AM fungi were identified, and, through split-root experiments, an additional layer of regulation, in the colonized or non-colonized sections of the mycorrhizal root system, was uncovered. Transcript profiles of the shoots of mycorrhizal plants indicated the systemic induction of many genes predicted to be involved in stress or defense responses, and suggested that mycorrhizal plants might display enhanced disease resistance. Experimental evidence supports this prediction, and mycorrhizal M. truncatula plants showed increased resistance to a virulent bacterial pathogen, Xanthomonas campestris. Thus, the symbiosis is accompanied by a complex pattern of local and systemic changes in gene expression, including the induction of a functional defense response.
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Affiliation(s)
- Jinyuan Liu
- Boyce Thompson Institute for Plant Research, Cornell University, Tower Road, Ithaca, NY14853, USA
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28
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Gao LL, Horbury R, Nair RM, Singh KB, Edwards OR. Characterization of resistance to multiple aphid species (Hemiptera: Aphididae) in Medicago truncatula. Bull Entomol Res 2007; 97:41-8. [PMID: 17298680 DOI: 10.1017/s0007485307004786] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Aphids are phloem-feeding insects that damage many important crops throughout the world yet, compared to plant-pathogen interactions, little is known about the mechanisms by which plants become resistant to aphids. Medicago truncatula (barrel medic) is widely considered as the pre-eminent model legume for genetic and biological research and in Australia is an important pasture species. Six cultivars of M. truncatula with varying levels of resistance to two pests of pasture and forage legumes, the bluegreen aphid Acyrthosiphon kondoi Shinji and the spotted alfalfa aphid Therioaphis trifolii f. maculata. (Buckton) are investigated. Two resistance phenotypes against T. trifolii f. maculata are described, one of which is particularly effective, killing most aphids within 24 h of infestation. Each resistance phenotype provided a similar but somewhat less effective degree of resistance to the closely-related spotted clover aphid Therioaphis trifolii (Monell). In the case of A. kondoi only one resistance phenotype was observed, which did not vary among different genetic backgrounds. None of the observed resistance against A. kondoi or T. trifolii f. maculata significantly affected the performance of green peach aphid Myzus persicae (Sulzer) or cowpea aphid Aphis craccivora Koch. The existence of multiple aphid resistance mechanisms in similar genetic backgrounds of this model plant provides a unique opportunity to characterize the fundamental basis of plant defence to these serious agricultural pests.
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Affiliation(s)
- L-L Gao
- CSIRO Plant Industry, Wembley, WA, Australia
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29
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Ramamoorthy V, Zhao X, Snyder AK, Xu JR, Shah DM. Two mitogen-activated protein kinase signalling cascades mediate basal resistance to antifungal plant defensins in Fusarium graminearum. Cell Microbiol 2007; 9:1491-506. [PMID: 17253976 DOI: 10.1111/j.1462-5822.2006.00887.x] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Antifungal defensins, MsDef1 and MtDef4, from Medicago spp., inhibit the growth of Fusarium graminearum, which causes head blight disease in cereals. In order to determine the signalling cascades that are modulated by these defensins, we have isolated several insertional mutants of F. graminearum that exhibit hypersensitivity to MsDef1, but not to MtDef4. The molecular characterization of two of these mutants, designated enhanced sensitivity to defensin (esd), has revealed that the Mgv1 and Gpmk1 MAP kinase signalling cascades play a major role in regulating sensitivity of F. graminearum to MsDef1, but not to MtDef4. The Hog1 MAP kinase signalling cascade, which is responsible for adaptation of this fungus to hyperosmotic stress, does not participate in the fungal response to these defensins. Significantly, the esd mutants also exhibit hypersensitivity to other tested defensins and are highly compromised in their pathogenesis on wheat heads and tomato fruits. The studies reported here for the first time implicate two MAP kinase signalling cascades in a plant defensin-mediated alteration of fungal growth. Based on our findings, we propose that specific MAP kinase signalling cascades are essential for protection of a fungal pathogen from the antimicrobial proteins of its host plant.
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30
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Klingler JP, Edwards OR, Singh KB. Independent action and contrasting phenotypes of resistance genes against spotted alfalfa aphid and bluegreen aphid in Medicago truncatula. New Phytol 2007; 173:630-640. [PMID: 17244058 DOI: 10.1111/j.1469-8137.2006.01939.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Host resistance to aphids is poorly understood. Medicago truncatula, a model legume and cultivated pasture species, was used to elucidate defense against two aphid species, Therioaphis trifolii f. maculata (spotted alfalfa aphid, SAA) and Acyrthosiphon kondoi (bluegreen aphid, BGA). Aphid performance and plant damage were compared between near-isogenic cultivars, Mogul and Borung, that differ in resistance to both aphids. Analyses of aphid resistance in Mogul x Borung F2 plants and their progeny revealed modes of action and chromosome locations of resistance genes. Separate genes were identified for SAA resistance (TTR) and BGA resistance (AKR); both mapped to chromosome 3 but were found to act independently to reduce survival and growth of their target aphid species. The TTR locus controls distinct, and contrasting, local and systemic plant responses between the near-isogenic cultivars. TTR-mediated plant responses imply interaction between a resistance factor(s) in vascular tissue and a bioactive component(s) of SAA saliva. Features of both resistance traits suggest homology to aphid resistance in other legumes; elucidation of their molecular mechanisms will likely apply to other aphid-plant interactions.
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Affiliation(s)
- John P Klingler
- Commonwealth Scientific and Industrial Research Organization Entomology and
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Private Bag 5, Wembley, WA 6913, Australia
| | - Owain R Edwards
- Commonwealth Scientific and Industrial Research Organization Entomology and
| | - Karam B Singh
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Private Bag 5, Wembley, WA 6913, Australia
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