The Function Analysis Of Rice Transcription Factor OsMYB1R1 In Stress Response

Rice(Oryza sativa L.) grouth may be affected by different kinds of adverse environment factors during the whole growing cycle. Abiotic stresses are among those factors that can severely affects rice yield and quality and resulted in huge economic losses every year. Therefore, the research of rice abiotic stress response related genes, their mechanism of action, and abiotic stress response signal network can help us know the mechanism in response to abiotic stress in plant, and guide us for genetic improvement of rice and other food crops to ensure food crops production stable and high yield.MYB transcription factor family has a large number of members, and involves in various physiological and biochemical reactions through a variety of signaling networks in plants. The main functions among them include affecting growth and development, adjustment of secondary metabolites synthesis, transduction hormone signal transduction and regulation of response to stresses in plant. In this study, OsMYB1R1 overexpression and OsMYB1R1 RNAi plants were used as experimental materials to study the function of rice transcription factor OsMYB1R1 in response to abiotic stress The main findings are as follows:1. OsMYB1R1 gene expression patterns in rice under different stress confirmed that OsMYB1R1 gene responses to drought, high salt, high temperature and ABA. The study of OsMYB1R1 gene expression in different rice organs verified that OsMYB1R1 expression is highest in panicle.2. abiotic stress of OsMYB1R1 overexpression, OsMYB1R1 RNAi and wild type seedling were compared under drought, high temperature and high salt treatments. The results showed that increase in OsMYB1R1 gene expression reduced tolerance to drought and high salt, while the decrease in OsMYB1R1 gene expression enhanced drought and high salt tolerance. the tolerance to high temperature has no significantly differences between three kinds of plants with different OsMYB1R1 expression level.3. Drought treatment experiments of OsMYB1R1 overexpression, OsMYB1R1 RNAi and wild type at different stages revealed that changes of OsMYB1R1 gene expression did not affect rice drought tolerance at seed germination stage. At seedling, booting and flowering stage, drought tolerance of OsMYB1R1 overexpression plants was lower than the wild type, while drought tolerance of OsMYB1R1 RNAi plants was stronger than wild type.4. Proline(Pro) content, relative conductivity and other physiological and biochemical indexes were measured and analyzed after drought treatments at seedling stage and booting stage. The leaf water loss rate of OsMYB1R1 overexpression plants was higher than that of wild type, while OsMYB1R1 RNAi plants was lower than that of wild type. At the same time, the malondialdehyde(MDA) content and relative conductivity of OsMYB1R1 overexpression plants was higher than that of the wild type, the proline content was lower than that of the wild type after drought and high salt treatment experiments. The situation of OsMYB1R1 RNAi plant was just the reverse of OsMYB1R1 overexpression plants.5. The OsMYB1R1 expression and OsMYB1R1 RNAi seed were treated by exogenous ABA to verify the relationship between the OsMYB1R1 gene expression level and plant response to ABA. It was found that the decrease in OsMYB1R1 gene expression could increase rice sensitivity to ABA.