The Roles Of Heat Shock Factors And XooIARP In Resistance To Bacterial Blight In Rice

Bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae(Xoo) was one of the three destructive diseases of rice(Oryzae sativa L.), causing the major loss of rice production in China. With existing resistance overcomed by new Xoo race, it is necessary to get new genes resistant to BB from wild rice. SH5 and SH76 contain novel BB resistance gene that was introduced into a cultivated japonica rice variety 8411, via somatic hybridization using the wild Oryzae meyeriana as the donor. By using the proteomic analyses, an auxin-regulated protein from the new hybrids was found, which was named XooIARP(Xanthomonas oryzae pv. oryzae.-induced auxin regulated protein).In this paper the function of XooIARP was studied by using transgenic method. Meanwhile, the expression patterns of seven heat shock factors(OsHSFs) were analysed in 8411, SH5 and SH76. Our results are summarized as follows.1. Seven differentially expressed OsHSFs were chosen from the microarray results, and their expression patterns were analyzed in leaves inoculating Xoo for 12h,24h,48h and 72h by reverse transcriptase polymerase chain reaction (RT-PCR) In contrast with 8411, only OshsfB2C2 was up-regulated in two new germplasms.2. Sequence analysis indicated that XooIARP contained two repeats of the N-terminal domain of glutathione S-transferase (GST) and may function as glutathione S-transferase. The prokaryotic expression vector pSKB.4 plus T7 promoter was constructed. After IPTG inducing, the fusion protein band with predicted molecular mass appeared on SDS-PAGE.3. XooIARP was first reported to be involved in the plant-pathogen interaction. In order to understand its role in resistance to BB, the over-expression and RNAi vectors of XooIARP gene under the regulation of cauliflower mosaic virus 35s promoter were constructed. Then the rice calluses were infected by Agrobacterium tumefaciens EHA105 with vectors, and hygromycin resistant seedings were obtained. XooIARP was integrated into the genome of the plants by PCR identification.