Functions Of ERFL1a Transcription Factor In Drought Stress And Starch Synthesis In Bread Wheat(Triticum Aestivum.L)

In our previous study,the expression of Ta ERFL1 a,a member of AP2/ERF transcription factors,was markedly induced in wheat seedlings suffering freezing stress,inferring its important role in wheat response to abiotic stresses.To verify its role and explore its molecular mechanism,in this study,the roles and molecular mechanism of Ta ERFL1 a in wheat were identified by using BSMV-VIGS and yeast two-yeast hybrid library screening,respectively.The main results were summarized as follows:(1)c DNA sequence of Ta ERFL1 a was isolated from wheat and the length of its open reading frame is 732 bp,encoding a putative protein of 243 amino acids.Phylogenetic tree analysis indicated that it is a novel member of B1 subgroup of ERF family.And subcellular localization assay indicated that it is localized at the nucleus of tobacco leaves.(2)q PCR results indicated that Ta ERFL1 a transcript levels remarkably increased under abiotic stresses(cold,salt,and water deficiency)and abscisic acid(ABA)hormone.The tolerance of Ta ERFL1 a in BSMV-Ta ERFL1a-infected wheat seedlings were significantly reduced PEG-induced water deficiency.The results indicated that Ta ERFL1 a,one member of ABA signalling pathway,could be positively associated with abiotic stresses in bread wheat.(3)Under field condition,expression of Ta ERFL1 a was also inhibited significantly in wheat genome,and the silenced wheat plant exhibited the markedly decreased grain weight,length,width and starch contents.In addition,scanning electron microscope observation showed that the morphology of grain starch granules was dramatically changed and its number became fewer.These results inferring that Ta ERFL1 a response to grain starch synthesis in bread wheat.(4)Ta ERFL1 a was found to possess transcriptional activation activity,and six interacting proteins were identified by yeast two-hybrid library screening assay,which were further confirmed by using yeast co-transformation experiment and Bi FC in tobacco leave and onion.Of these identified proteins,the promoters of the genes encoding three proteins contained the Ta ERFL1a-binding GCC-box or DRE/CRT elements.These results suggested that Ta ERFL1 a could play important roles in wheat response to abiotic stresses and starch synthesis by interacting with these proteins in bread wheat.