Plant, Animal & Microbe Genomes X Conference

January 12-16, 2002
Town & Country Convention Center
San Diego, CA

Poster: Large Insert Libraries
            

GENOME-WIDE ORGANIZATION AND EVOLUTION OF DISEASE RESISTANCE GENE FAMILIES IN THE CULTIVATED RICE, ORYZA SATIVA L.

¹ Department of Soil and Crop Sciences and Institute for Plant Genomics and Biotechnology, 2123 TAMUS, Texas A&M University, College Station, TX 77843-2123, USA

Diseases are a major constraint to crop production. To control them in agriculture using molecular tools, at least 33 genes conferring to different plant pathogens have been isolated to date. Sequence analysis led to classification of these genes into eight classes (families). Using the cloned genes as tools, we are studying the genome-wide organization and evolution of the disease resistance (R) gene families in the grass genomes using rice as a model system. We analyzed the sequences of the cloned R genes, designed primer pairs from the conserved domains of each of the eight R gene families and PCR-amplified the different members of each R gene subfamily or family using the genomic DNA of the cultivated rice, Oryza sativa L. ssp. indica and japonica, and tomato as templates. Three large-insert BAC libraries of Indica rice and three large-insert BAC and BIBAC libraries of Japonica rice were screened with the purified radiolabeled-PCR products of each R gene subfamily or family. The positively hybridized clones were analyzed by restriction fingerprinting and contig assembly. The organization of each family of the R genes in an R gene cluster was determined. Each cluster of the R genes will be positioned to the whole-genome, BAC-based physical maps of the rice genomes developed in our laboratory, and the genome-wide organization and evolution of the R genes in the rice genome will be determined. These results will provide an insight into the genome-wide organization and evolution of the R gene families in the grass genomes.