PhERF6, interacting with EOBI, negatively regulates fragrance biosynthesis in petunia flowers.

In petunia, the production of volatile benzenoids/phenylpropanoids determines floral aroma, highly regulated by development, rhythm and ethylene. Previous studies identified several R2R3-type MYB trans-factors as positive regulators of scent biosynthesis in petunia flowers. Ethylene response factors ( ERFs) have been shown to take part in the signal transduction of hormones, and regulation of metabolism and development processes in various plant species., Using virus-induced gene silencing technology, a negative regulator of volatile benzenoid biosynthesis, Ph ERF6, was identified by a screen for regulators of the expression of genes related to scent production., Ph ERF6 expression was temporally and spatially connected with scent production and was upregulated by exogenous ethylene. Up-/downregulation of the mRNA level of Ph ERF6 affected the expression of ODO1 and several floral scent-related genes. Ph ERF6 silencing led to a significant increase in the concentrations of volatiles emitted by flowers. Yeast two-hybrid, bimolecular fluorescence complementation and co-immunoprecipitation assays indicated that Ph ERF6 interacted with the N-terminus of EOBI, which includes two DNA binding domains., Our results show that Ph ERF6 negatively regulates volatile production in petunia flowers by competing for the binding of the c-myb domains of the EOBI protein with the promoters of genes related to floral scent. [ABSTRACT FROM AUTHOR]