Functional Analyses of Rice Genes in 20,000 Rice-Arabidopsis FOX Lines Showing Resistance to Bacterial Pathogen Pst3000

Abstract

About 13,000 full-length cDNAs of rice were mixed and ligated to an expression vector cassette and introduced into Arabidopsis by Agrobacterium-mediated floral dip transformation to generate Rice-Arabidopsis FOX (full-length over-expressor) lines. Three-week-old T2 seedlings from approximately 20,000 FOX lines were screened for resistance to a bacterial pathogen, Pseudomonas syringae pv. tomato DC3000 (Pst3000) by dip inoculation. After 3 rounds of screening, 69 resistant lines were selected and more than 50 rice cDNAs inserted in their genomes were identified. The rice cDNAs identified by this procedure are being re-transformed into Arabidopsis and rice for overexpression and further screening to confirm the disease-resistant phenotypes. At present, at least 13 rice cDNAs endowed resistance to Pst3000 in Arabidopsis. We are now analyzing the mechanism(s) for disease resistance in each resistant line by qPCR. In addition, results of screening for resistance to Xanthomonas oryzae of rice transgenic lines (T1 generation) will be reported.