Lily (Lilium spp.) LhERF061 suppresses anthocyanin biosynthesis by inhibiting LhMYBSPLATTER and LhDFR expression and interacting with LhMYBSPLATTER.

Ethylene has an essential function in the biosynthesis of anthocyanin. However, the molecular mechanism through which ethylene impacts the color of lily flower remains little appreciated. This study identified LhERF061, a dehydration-responsive element-binding (DREB family) transcription factor that suppresses anthocyanin biosynthesis in response to ethylene in lilies. Transient LhERF061 overexpression caused a dramatic decrease in anthocyanin levels and downregulated both anthocyanin structural genes and positive regulators in lily tepals. Heterologous LhERF061 expression in Arabidopsis and tobacco also suppressed anthocyanin accumulation. Mechanistically, LhERF061 was found to bind to the promoters of LhMYBSPLATTER (a positive regulator of the biosynthesis of anthocyanin) and LhDFR (an anthocyanin structural gene), thereby inhibiting their transcriptional activity. Further investigation indicated that LhERF061 physically interacted with LhMYBSPLATTER, thereby interfering with the MYB-bHLH-WD40 (MBW) complex responsible for anthocyanin regulation, providing multiple mechanisms for inhibiting the biosynthesis of anthocyanin. These results provide insights into how ethylene mediates the biosynthesis of anthocyanin and increase understanding of the regulatory network of the biosynthesis of anthocyanin in lily.