The interplay of transcription factors in suppression of UV-B induced flavonol accumulation by flg22.

Biotic stress can be mimicked by application of elicitors, which comprise of microbe-associated molecular patterns (MAMPs). Treatment of plant cell cultures with MAMPs such as flg22 suppressed the expression of UV-B-induced flavonol pathway genes (FPGs) in parsley, carrot and Arabidopsis. This is thought to allow the plant focusing its secondary metabolism on the pathogen defense during MAMP-triggered immunity (MTI). Recently we reported that this suppression also depends on prevention of histone 3 acetylation at lysine 9 (H3K9ac), a hallmark for gene activation. Here we describe a possible regulation between UV-B and flg22 signaling cascades, and the interplay of MYB and WRKY transcription factors in regulating the expression of the FPGs.