Functional Identification Of The Arabidopsis Myb Transcription Factor ATMYB20 In Response To Drought Stress

Due to the global climate change and human exploitation of energy resources, the water resources decline, and soil drought becomes more serious. Accompanied by the significant changes in the environment, plants suffer growing drought stress. Because of this, the crop production is significantly reduced. However, some plants have developed various strategies to tolerate the drought stress. Under the adverse stress, they may produce the appropriate response and activate the corresponding cell signaling pathways to avoid the damage. MYB transcription factors is an important class of transcription factors in plants and play an important role in many aspects of plant including phenylpropanoid secondary metabolism and plant response to abiotic stress.In this study, we focused on identify the role of AtMYB20 in response to drought and other abiotic stress in plants. Though RT-PCR analysis of the expression of AtMYB20 under low temperature, high salinity, drought and ABA treatments, it was indicated that AtMYB20 was down-regulated by low temperature, drought and ABA, while up-regulated by high salinity. By studying the induced response of this gene to ABA, which in detail is determining the influence to seed germination, root length, fresh weight, and cotyledon turning green under ABA treatment, we found the expression of AtMYB20 was shown to be negative correlation with rate of cotyledon turning green. By analyzing the influence of this gene to stomatal movement and ROS accumulation, we found the expression of AtMYB20 was negative correlation with ABA-induced stoma closure and ROS accumulation. By exploring the phenotype change of plants of different genotype under water shortage, we found that the mutant of AtMYB20 displayed enhanced tolerance to drought. By analyzing the influence of this gene to the expression of drought-resistance-relative genes which can response to ABA, we found the results indicated that the expression of AtMYB20 showed negative correlation with that of drought-resistance-relative genes. Based on all the experiments above, we primarily identified that AtMYB20 could play a role as a negative regulator in ABA-dependent drought stress signal regulating pathways.