The NAC transcription factor MdNAC4 positively regulates nitrogen deficiency-induced leaf senescence by enhancing ABA biosynthesis in apple

Abstract Although it is well established that nitrogen (N) deficiency induces leaf senescence, the molecular mechanism of N deficiency-induced senescence remains largely unknown. Here, we show an abscisic acid (ABA)-responsive NAC transcription factor (TF) involved in senescence. The overexpression MdNAC4 led to increased ABA levels apple calli by directly activating biosynthesis gene MdNCED2 . In addition, promoted Further investigation showed bound promoter senescence-associated (SAG) MdSAG39 and upregulated its expression. Interestingly, function promoting was enhanced presence ABA. Furthermore, identified interaction between receptor protein MdPYL4 protein. Moreover, a similar ABA-mediated These findings suggest plays central role interacts with enhance response latter deficiency, thus conclusion, our results provide new insight into how regulates Graphical