Function Analysis Of Transcription Factor BHLH146 In Arabidopsis Thaliana

bHLH(Basic Helix-Loop-Helix)transcription factor involved in plant growth and development,response to abiotic stress,but the molecular mechanisms of b HLH regulating plant cell elongation,signal transduction,and stress resistance have not been understood fully.In this study,we identified an unknown function of the b HLH transcription factor bHLH146 in Arabidopsis thaliana,and explored its molecular mechanisms involved in regulating the growth and development and abiotic stress.The main results are as follows:1.We cloned successfully the target gene bHLH146(At4g30108).2.We idenfited homozygous mutants and overexpression plant.Overexpressed plants have phenotypes of short leaves,shortened hypocotyl and small epidermal cells.The q PCR results indicate that the phenotypes are caused by inhibition of cell elongation-related genes EXP1 and EXP8.3.The germination rate of overexpressed plants decreased and the rate became slower in ABA treatment,and the survival rate of overexpressed plants was significantly higher than that of wild-type plants in drought treatment.The experimental results showed that atbHLH146 responded to ABA and drought stress,and the overexpression bHLH146 enhanced the sensitivity of ABA and drought resistance.4.The results of subcellular localization experiments show that bHLH146 is localized in the nucleus.Yeast two-hybrid and bimolecular fluorescence(Bifc)results show that bHLH146 interacted with the b HLH family BEE1 and PRE2 proteins.Our study identified a function-unknown b HLH transcription factor AtbHLH146.BHLH146 interacted with the b HLH transcription factors PRE2 and BEE1.BHLH146 inhibited two EXPANSIN genes encoding cell wall–loosening enzymesit,thereby regulated plant cell elongation networks.BHLH146 may also involved in the drought tolerance of Arabidopsis thaliana.