Flg22 regulates MAP kinase 6 interaction with an ethylene response factor substrate via ethylene

Despite their importance, plant MAP kinase targets are still poorly elucidated. Here, the specific in vivo interaction of an ethylene response factor (ERF104) with the Arabidopsis MAP kinase, MPK6, is shown by fluorescence resonance energy transfer. The interaction, which is lost within minutes after treatment with the flagellin-derived flg22 peptide, is dependent on both MPK6 kinase activity and rapid ethylene signaling initiated downstream of MPK6 activation. ERF104 is an MPK6 substrate and phosphorylation site mutations affected its stability. ERF104 activates promoters with GCC elements. This was evident from microarray data of overexpressing transgenic plants, where promoters of up regulated genes contain GCC motifs and chromatin immunoprecipitation showing ERF104 association with PDF1.2 promoter. The ERF104 overexpressor did not affect biotrophic bacteria proliferation but was more susceptible to necrotrophic Botrytis cinerea. Microarray performed with erf104 or mpk6 revealed only a limited number of flg22-induced genes that require these elements - possibly as a

24

Bethke G, Unthan T, Uhrig JF, Pöschl Y, Gust AA, Scheel D, Lee J