Founction Analysis Of Stress Resistance Genes OsPDCD5 And OsbHLH59 In Rice

Environmental stresses, such as drought, soil salinization, and extreme temperature, have seriously limited crop plant growth and yield production. Dissecting the signal pathway of plant responding to environmental stress, and identifying functional candidate genes for stress resistance in plant will provide valuable information to develop stress resistance varieties in crop.This thesis consists of two parts. The first part was based on previous work. Previous results in our lab showed that the programmed cell death (PCD) was involved in the response to salt and osmotic stresses in rice plant. In this study, a PCD related gene OsPDCD5, were used for further analysis. OsPDCD5-RNAi transgenic lines of IR64, Minghui63/Bt, C418, and Nipponbare had been obtained, and their phenotypic performance under stress has been evaluated. Phenotypic performance of these transgenic plants under stresses indicated that the drought resistance was largely improved by repressing the expression of OsPDCD5. In the second part, a transcription factor gene, OsbHLH59, was selected as functional candidate gene of stress resistance according to previous macroarray result, and its over-expression vector was constructed through Gateway technology. The gene OsbHLH59 successfully was over-expressed in transgenic plants of Arabidopsis and rice. As well, its GFP fusion expression vector had been constructed, and OsbHLH59 were located in the nucleus according to the result of subcellular localization experiment by using transient expression assay in onion epidermis cells. Phenotypic performance of these transgenic lines under stresses indicated that over-expression of OsbHLH59 resulted in low germination rate of Arabidopsis and also increasing the sensitivity to salt stress. The molecular mechanism of these genes involved in stress response need to be further determined.