论文部分内容阅读
Phytohormone ethylene controls diverse developmental and physiological processes such as fruit ripening via modulation of ethylene signaling pathway.Our previous study indicated that EHYLENE RESPONSE FACTOR11(MaERF11),a transcription factor in ethylene signaling pathway,negatively regulated the ripening of banana,but the underlying transcriptional regulatory mechanism remains unknown.Here we report the identification of several direct targets and a protein interaction partner,shedding light on the mechanism of MaERF11 function.Dual-luciferase reporter assay(DLR)indicated that MaERF11 possesses intrinsic transcriptional repression activity in planta.Electrophoretic mobility shift assay(EMSA)and chromatin immunoprecipitation(ChIP)experiments demonstrated a specific binding of MaERF11 to promoters of three ripening-related Expansin genes,namely MaEXP2,MaEXP7 and MaEXP8,as well as an ethylene biosynthetic gene MaACO1,via GCC box,suggestive of direct targets of MaERF11.Moreover,protein-protein interaction analysis revealed that MaERF11 physically interacted with a histone deacetylase MaHDA1 both in vitro and in vivo,and co-expression of MaHDA1 significantly strengthened the MaERF11-mediated transcriptional repression of MaACO1 and Expansins.In addition,ChIP experiments demonstrated enhanced histones H3 and H4 acetylation levels of MaACO1,MaEXP2,MaEXP7 and MaEXP8 in fruit ripening,which coincided with their mRNA levels during ripening.Taken together,these findings suggest that MaERF11 may recruit MaHDA1 to the regulatory regions of its targets MaACO1,MaEXP2,MaEXP7 and MaEXP8,thus resulting in the repression of their expression possibly via modification of histone acetylation.