Plant & Animal Genomes XV Conference

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

Comparative Analysis Of Multiple Disease Resistance In Maize And Rice

Rebecca Nelson¹ , Peter Balint-Kurti² , Darshan Brar⁴ , Masdiar Bustamam³ , Gay Carillo⁴ , Chia-lin Chung¹ , M. Genaleen Diaz⁶ , James Gethi⁵ , Jedidah Danson⁵ , Jane Ininda⁵ , Judith Kolkman¹ , Jan Leach⁶ , Hei Leung⁴ , Ramil Mauleon⁴ , Jesse Poland¹ , Margaret Smith¹ , Utut Suharsono⁷ , Casiana Vera Cruz⁴ , Randall Wisser²

¹  Cornell University, Ithaca, NY, 14853, USA

²  USDA-ARS, North Carolina State University, Raleigh, NC, 27695, USA

³  Indonesian Centre for Agricultural Biotechnology and Genetic Resources Research and Development, Bogor, Indonesia

⁴  International Rice Research Institute, Los Banos, Philippines

⁵  Kenya Agricultural Research Institute, Nairobi, Kenya

⁶  Colorado State University Ft. Collins, CO, 80523-1177, USA

⁷  Bogor Agricultural University, Bogor, Indonesia

This Generation Challenge Program project is aimed at identifying and characterizing disease QTL (dQTL) in maize and rice. The phenomenon of multiple disease resistance (MDR), in which a locus conditions quantitative resistance to multiple pathogen taxa, is of particular interest for both practical and conceptual reasons. We are developing and/or utilizing a set of interrelated genetic resources in maize and rice to permit the genetic dissection of quantitative disease resistance in general and MDR in particular. QTL syntheses in both maize and rice indicated that MDR exists on the level of chromosome segments (Wisser et al., 2005; Wisser et al., 2006). To determine whether it exists at the gene level, a maize panel designed for association mapping (Flint-Garcia et al., 2005) was screened for resistance to two maize diseases. A significant genetic correlation was detected between responses to the two diseases, supporting the hypothesis that a component of the defense response is effective against the two diseases. In maize, we have conducted selection mapping to identify desirable QT alleles, and near-isogenic lines are being developed for the dissection and detailed characterization of dQTL. In rice, a collection of deletion mutants is being used to dissect dQTL. Several methods have been utilized to identify deletion mutants covering a given gene of interest, and/or to characterize the genes deleted in a mutant showing a phenotype of interest. Candidate genes are being identified through a range of criteria, including microarray experiments identifying differentially expressed genes and clusters of genes with correlated expression. Candidate genes will be verified through association analysis in maize and mutant analysis in rice.