Cloning And Functional Analysis Of Rice Defense-related Gene OsDRxocl And OsDRxoc2

Rice is one of the most important crops in the world. Bacterial streak, caused by Xanlhomonas oryzae pv. oryzicola (Xoc), is one of the most serious diseases of rice worldwide, resulting yield loss of ten to twenty percent for each year. Until now, it is really a big threat to world food production without any effective method to control this disease.In this study, we cloned and functional analysis of two up-regulated genes OsDRxocl and OsDRxoc2after Xoc inoculaton. OsDRxocl-eneoded a putative MYB transcription factor protein in rice. OsDRxoc2encoded an unknown function protein. In general, we firstly constructed the overexpression (named as pU1301-OsDRxocl and pU1301-OsDRxoc2) and RNAi vector (ds1301-OsDRoxl and dsl301-OsDRxoc2) of OsDRxocl and OsDRxoc2, and then introduced into both rice varieties Mudanjiang8(MDJ8) and Zhonghuall (ZHll). For OsDRxocl gene, we have achieved for seventeen and twenty-six positive transgenic lines for pU1301-OsDRxocl and dsl301-OsDRoxl with rice variety ZHll, respectively. And for constructs pUl30l-OsDRxoc2and dsl30l-OsDRox2, eeleven and twenty-one positive individuals were achieved with MDJ8, and thirteen and twenty-six positive individuals with ZHll respectively.At To generation, transgenic plants carried pUl301-OsDRxocl appear to smaller, yellow leaves, flowering delay, seed setting rate reducing, which compared to wild type and native transgenic control. Further study indicated that the yellow leaf phenotype is caused to decreasing content of chlorophyll in leaves。After inoculation with Xoc isolates RS105at T1generation, transgenic lines carried pU1301-OsDRxocl were identified to enhance resistant to RS105, and lines carried ds1301-OsDRoxl were more susceptible to RS105. On the contrary, this phenotypic change was turned over for inoculation of PXO99. Overexpression of OsDRxocl resulted in more susceptible to PXO99, and repressed expression of OsDRxocl enhanced resistance. This is indicated that OsDRoxl was not only involved into both plant defense and plant development, but also, it will help to elucidate the core differences of infection mechanism between Xoo and Xoc. For OsDRxoc2gene, we concluded that it were not affected the susceptibility of RS105for both overexpression and repressed expression of OsDRxoc2. It was increased to resistant to PXO99and drought stress after overexpression of OsDRxoc2, and more sensitive for both stress after repressed expression. This helps us to address that OsDRxoc2was a key factor to regulate the resistant to PXO99and abiotic stress.