Induction Of NAC103 Expression By NAC062 Promotes Cell Survival Under Endoplasmic Reticulum Stress

When subjected to environmental stress,a mass of unfolded and misfolded proteins may accumulate in ER of eukaryotes,thus resulting in ER stress.In order to alleviate the toxicity caused by stress,the unfolded protein response（UPR）is activated to assist the protein folding in ER.In this process,transcription factors play an extremely important role.According to previous studies,transcription factors NAC062 and NAC103 both play an important role in up-regulating UPR gene to promote cell survival under ER stress in Arabidopsis thaliana.However,the upstream and downstream relationship between NAC062 and NAC103 in ER stress signal regulation pathway remains to be unclear.In this study: 1)Under ER stress,overexpression of NAC062 could up-regulate the expression of NAC103;2)Overexpression of NAC062D（NAC062 nuclear localization form）could up-regulate the expression of NAC103;3)Through dual-luciferase reporter assay and yeast one hybrid（YIH）assay,it was found that NAC062 D could directly bind to NAC103promoter;4)Arabidopsis WT plants and nac062 mutant plants（WT）were treated with TM for 4h respectively,thus causing ER stress;the expression of NAC103 in Arabidopsis WT plants was up-regulated after TM treatment,but the up-regulation of NAC103 in nac062 mutant plants（WT）was not affected compared with that in WT plants,indicating that NAC062 played a redundant role in the up-regulation of NAC103 expression in ER stress pathway;5)The results of q RT-PCR analysis showed that the expression of NAC062 and NAC103 genes were up-regulated by high salt,drought and cold stress environment,which further suggests that NAC062 and NAC103 may participate in other abiotic stress pathways such as drought,salt and cold stress.In conclusion,the relationship between NAC062 and NAC103 is studied by means of molecular biology in this study,which plays an important role in improving the ER stress signaling pathway.Meanwhile,it is helpful to understand their role in biotic and abiotic stress pathways,so as to improve the tolerance of plants to environmental stress,and provide a solid theoretical basis for genetic breeding and molecular breeding of crops.