Functional Analysis Of Rice OsBWMK1in Disease Resistance And Abiotic Stress

Plants recognize and transduce environmental and developmental signals by a series of intracellular signaling pathways, resulting in physiological and biochemical responses. Of which protein phosphorylation and dephosphorylation play a crucial role to transduce and integrate these signals to switch relevant gene expression. The mitogen-activated protein kinases (MAPKs) are key components, which regulate numerous processes, including stress and hormonal responses, innate immunity, and developmental programs.In this study, the rice BWMK1gene, a blast and wounding MAP kinase gene, was investigated in innate immunity and abiotic stress by generation of trnagenic rice with overexpression and RNA interference of BWMK1gene. The results were sumarised as follow.1. BWMK1was obtained using the method of RT-PCR, and sequence analysis confirms this was a fragment of rice MAP kinase gene BWMK1.2. Using the cleavage and ligation method to construct the over-expression and RNA interference vectors. Two vectors were respectively transformed to the Agrobacterium LBA4404via electric transformation.3. These expression vectors were then delivered into rice cultivar Nipponbare by Agrobacterium-mediated transformation. Forty five transgenic plants were obtained.4. Of them, a homozygote of overexpression plant, named Os17-5-3, and a homozygous RNAi plant, named Ampk17-6-3, were confirmed by PCR amplification, semi-quantitative analysis.5. Morphology of those homozygotes was observed, suggesting that overexpression of BWMK1suppresses seed germination and seedling growth.6. Physiological and biochemical responses of drought and salinity indicated that RNAi plants displayed drought tolerance, while overexpression plants displayed more sensitive. Moreover, the content of relative water and NO in over-expression plants were higher than that of in RNAi plants under drought stress.7. Pathogens inoculation experiment indicated that the over-expression plants were more resistant to pathogens than that of RNAi plants.8. The expression of related marker genes downstream BWMK1were detected by real-time PCR after treatment with Xanthomonas oryzae pv. oryzae (Xoo), the causual agent of rice bacterial blight. The results showed that the expression of BWMK1, OsEREBP1, OsPRl and OsWRKY33were firstly increased and then decreased in wild type plants, over-expression plants and RNAi plants. But the expression peaks of BWMK1and OsEREBP1in RNAi plants were earlier than that of in over-expression plants; in addition, the high expression of BWMK1and OsEREBP1lasted shorter in RNAi plants than that of in over-expression plants. The expression of OsPR1in over-expression plants was enormous, while it was barel in RNAi plants; nevertheless, OsWRKY33displayed a enormous expression in RNAi plants and it was minimal in over-expression plants.