Plant & Animal Genomes XV Conference

January 13-17, 2007
Town & Country Convention Center
San Diego, CA

Medicago truncatula Pathosystems Involving Necrotrophs

Simon R Ellwood¹ , Judith Lichtenzveig^{1, 2} , Theo Pfaff¹ , Jonathan Anderson² , Lars Kamphuis¹ , Nola D'Souza¹ , Stephanie Whitehand² , Karam Singh² , Richard Oliver¹

¹  Australian Centre of Necrotrophic Plant Pathogens, Murdoch University, Perth, Western Australia, 6150, Australia

²  CSIRO Plant Industry, Floreat, Perth, Western Australia, 6014, Australia

Resistance to necrotrophic pathogens is poorly understood, and few resistance genes have been isolated. M. truncatula is host to many necrotrophs, several of which are not found on the most intensively studied plant model, Arabidopsis. We are currently resistance in M. truncatula to a range of root and foliar pathogens, including Ascochyta lentis, Ascochyta rabei, Colletotrichum coccodes, Fusarium oxysporum, Phoma medicaginis, Phytophthora medicaginis, Rhizoctonia solani and Stagonospora meliloti. Selected plant-pathogen interactions are being further characterized by examining defense gene expression. In the Phoma – Medicago pathosystem the focus has been on two F₂ populations segregating for resistance. In both, disease symptoms are quantitative and resistance is recessive. One represents a relatively wide cross which displays biased gamete representation and a different major resistance QTL (rnpm1) compared to a narrow cross with the same resistant parent (rnpm2). Recent progress will be presented.