DcEIL3-1, DcWRKY75 and DcHB30 transcription factors form an activation-inhibition module to regulate petal senescence in carnation (Dianthus caryophyllus L.)

Petal senescence affects the ornamental and economic value of carnation (Dianthus caryophyllus L.), one of the most important and typical ethylene sensitive cut flowers worldwide. Previous studies have revealed the molecular mechanisms of DcEIL3–1-DcWRKY75 transcriptional activation module and antagonistic competition between transcription factors DcWRKY75 and DcHB30 in regulating the expression of ethylene biosynthesis genes DcACS1 and DcACO1 and senescence associated genes DcSAG12 and DcSAG29 during ethylene induced petal senescence in carnation, but the regulatory mechanism among these three transcription factors is still unknown. Here, we investigated the transcriptional regulation network between these three transcription factors, and found that DcWRKY75 and DcHB30 can directly bind each other's promoter and inhibit each other's expression. Further, we found that DcEIL3–1 and DcHB30 also can directly bind each other's promoter and inhibit each other's expression. These findings further enrich our understanding about the molecular mechanism in regulating ethylene induced petal senescence in carnation, and also provide new strategies for postharvest preservation of cut carnation flowers.