Alfalfa benefits from Medicago truncatula: The RCT1 gene from M. truncatula confers broad-spectrum resistance to anthracnose in alfalfa

• Published in: Proceedings of the National Academy of Sciences - PNAS 2008-08, Vol.105 (34), p.12164-12169
• Main Authors: Yang, Shengming, Gao, Muqiang, Xu, Chenwu, Gao, Jianchang, Deshpande, Shweta, Lin, Shaoping, Roe, Bruce A, Zhu, Hongyan
• Format: Article
• Language: English
• Subjects: Alfalfa; Alternative splicing; Anthracnose; Biological Sciences; Botany; Cloning; Cloning, Molecular; Colletotrichum; Colletotrichum - immunology; Colletotrichum trifolii; Conserved sequence; Disease resistance; gene expression; gene transfer; Genes; Genes, Plant - immunology; Genetics; Genomes; Genomics; Heredity; Introns; Legumes; map-based cloning; Medicago sativa; Medicago sativa - genetics; Medicago truncatula; Medicago truncatula - genetics; Medicago truncatula - immunology; molecular cloning; Molecular modelling; Molecular Sequence Data; Nucleotide sequence; nucleotide sequences; Pathogens; Plant Diseases - immunology; Plant Diseases - microbiology; Plants; Plants, Genetically Modified; RCT1 gene; Receptors, Interleukin-1 - genetics; Structure-function relationships; transgenes; Transgenic plants
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0802518105

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.