BnaC9.DEWAX1 Negatively Regulates Wax Biosynthesis via Transcriptional Suppression of .

Very-long-chain alkane plays an important role as an aliphatic barrier. We previously reported that was responsible for alkane biosynthesis in and improved plant tolerance to drought. However, how the expression of is regulated is still unknown. Through yeast one-hybrid screening, we identified a transcriptional regulator of , BnaC9.DEWAX1, which encodes AP2\ERF transcription factor. BnaC9.DEWAX1 targets the nucleus and displays transcriptional repression activity. Electrophoretic mobility shift and transient transcriptional assays suggested that BnaC9.DEWAX1 repressed the transcription of by directly interacting with its promoter. was expressed predominantly in leaves and siliques, which was similar to the expression pattern of . Hormone and major abiotic stresses such as drought and high salinity affected the expression of . Ectopic expression of in Arabidopsis plants down-regulated transcription levels and resulted in a reduction in alkanes and total wax loads in leaves and stems when compared with the wild type, whereas the wax depositions in the mutant returned to the wild type level after complementation of in the mutant. Moreover, both altered cuticular wax composition and structure contribute to increased epidermal permeability in overexpression lines. Collectively, these results support the notion that BnaC9.DEWAX1 negatively regulates wax biosynthesis by binding directly to the promoter, which provides insights into the regulatory mechanism of wax biosynthesis in .