Poplar PdMYB221 is involved in the direct and indirect regulation of secondary wall biosynthesis during wood formation

• DOI: 10.1038/srep12240
• Publication Date: 2015-07-16T09:18:08Z
• Authors: Xianfeng Tang; Yamei Zhuang; Guang Qi; Dian Wang; Huanhuan Liu; Kairong Wang; Guohua Chai; Gongke Zhou
• Keywords: Secondary cell wall; MYB; Ectopic expression

Abstract Wood is formed by the successive addition of secondary xylem, which consists cells with a conspicuously thickened wall composed mainly cellulose, xylan and lignin. Currently, few transcription factors involved in direct regulation biosynthesis have been characterized tree species. Here, we show that PdMYB221, poplar ortholog Arabidopsis R2R3-MYB factor AtMYB4, directly regulates during wood formation. PdMYB221 predominantly expressed developing protein it encodes localizes to nucleus acts as transcriptional repressor. Ectopic expression resulted reduced cell thicknesses fibers vessels inflorescence stems. The amounts xylose lignin were decreased key genes synthesizing three components was suppressed overexpression plants. Transcriptional activation assays showed repressed promoters PdCESA7/8 , PdGT47C PdCOMT2 PdCCR1 . Electrophoretic mobility shift revealed bound PdCESA8 promoters. Together, our results suggest may be negative formation through indirect suppression gene biosynthesis.