Functional Analysis Of MYC1 Gene In Regulation Of Abiotic Stress Response In Arabidopsis Thaliana

In recent years,as the global climate change and environmental pollution problems have become more serious,the risk of environment that plants face during their growth has also increased.Abiotic stress seriously affects plant growth and development,reduces crop yield and quality,and threatens human food security.Therefore,it is undoubtedly of important theoretical significance and application value to discover plant resistance genes and clarify their mechanism of action.We use the Arabidopsis MYC1 gene as the research object,combined with molecular biology methods,to explores the functional mechanism of this gene in plant abiotic stress response.The major research results are as follows:(1)The analysis of Arabidopsis MYC1 gene expression pattern shows that the gene express in Arabidopsis stems at the highest level,followed by siliques,Inforescences and roots,and less expressed in rosette leaves and stem leaves.Subcellular localization showed AtMYC1 protein locate in the nucleus.(2)Phenotypic analysis of atmyc1 mutants under different abiotic stresses showed that atmyc1 mutants have significant tolerance to iron-deficiency stress in plants,and the physiological indexes related to iron-deficiency response are improved.atmyc1 mutants also show slight tolerance to cadmium stress and salt stress,and no response to oxidative stress.Therefore,this study investigated the mechanism of the atmyc1 mutant responding to iron deficiency stress.(3)Constructing 35S:AtMYC1 gene overexpression transgenic plants,Compared with the wild type,it is more sensitive to iron-deficiency stress,and the physiological indicators related to iron-deficiency stress response are reduced,which further proves that AtMYC1 gene negatively regulates the iron-deficiency response of plants.(4)Analysis of the induced expression of AtMYC1 gene showed that compared with the wild type,the transcription and translation levels of AtMYC1 gene in Arabidopsis was significantly reduced under iron-deficiency stress conditions.(5)Under iron deficiency stress-induced conditions,the expression of iron deficiency related genes IRT1,FRO2,b HLH39,b HLH100,and b HLH101 in atmyc1 mutants increased significantly.(6)Further protein interaction and target gene transcription regulation analysis showed that AtMYC1 interacts with the plant iron absorption core transcription factor FIT protein,and inhibits FIT's transcriptional activation of target genes IRT1 and FRO2 regulator in the response to iron deficiency in plants.In conclusion,AtMYC1 gene may interact with plant iron absorption core transcription factor FIT protein to inhibit FIT's transcriptional activation of target genes IRT1 and FRO2,thereby participating in the regulation of plant iron deficiency stress response.This research not only reveals a new mechanism for plants to respond to irondeficiency stress,but also provides new genetic resources and technical approaches for molecular breeding of crop mineral nutrition.