Abstract:

Y73 is a progeny of asymmetric somatic hybridization from an elite japonica rice cultivar (Dalixiang) and a wild rice (Oryza meyeriana) and shows high resistance to bacterial blight. The expression of a NBSLRR gene in Y73 was induced notably after inoculation with Xanthomonas oryzae pv.oryzae(PXO124). In order to investigate the function of the gene in resistance to rice bacterial blight disease, the CDS of the gene (2 631 bp) was cloned by RTPCR and was named OsBBR1(bacterial blight resistancerelated gene 1). Furthermore, the overexpression and RNA interference vectors of the gene were constructed with pCAMBIA1300 and the transgenic rice lines were developed by Agrobacteriummediated transformation. Resistance assay of transgenic analysis revealed that RNA interference lines were more sensitive to rice bacterial blight, while the overexpressing lines shown higher resistance to bacterial blight compared with wild type plants. These results suggested that OsBBR1 was involved in the rice bacterial blight resistance. Furthermore, the analysis of subcellular localization showed that OsBBR1 localized in cell plasma membrane and nuclear. This result indicated that OsBBR1 was probably involved in the signal transduction and the regulation of the transcription of downstream genes．

Key words: rice, bacterial blight, NBSLRR domain, OsBBR1, overexpression, RNAi