PagMYB128 regulates secondary cell wall formation by direct activation of cell wall biosynthetic genes during wood formation in poplar  

作　　者：Yuanyuan Hao Fachuang Lu Seung-Won Pyo Min-Ha Kim Jae-Heung Ko Xiaojing Yan John Ralph Quanzi Li 

机构地区：[1]State Key Laboratory of Tree Genetics and Breeding,Chinese Academy of Forestry,Beijing 100091,China [2]Department of Biochemistry and DOE Great Lakes Bioenergy Research Center,Wisconsin Energy Institute,University of Wisconsin-Madison,Wisconsin 53726,USA [3]Department of Plant&Environmental New Resources,Kyung Hee University,Yongin 17104,Korea

出　　处：《Journal of Integrative Plant Biology》2024年第8期1658-1674,共17页植物学报（英文版）

基　　金：supported by the National Key Research and Development Program of China(2021YFD2200900 to X.J.);funded by the DOE Great Lakes Bioenergy Research Center(DOE BER Office of Science DE-SC0018409)。

摘　　要：The biosynthesis of cellulose,lignin,and hemicelluloses in plant secondary cell walls(SCWs)is regulated by a hierarchical transcriptional regulatory network.This network features orthologous transcription factors shared between poplar and Arabidopsis,highlighting a foundational similarity in their genetic regulation.However,knowledge on the discrepant behavior of the transcriptional-level molecular regulatory mechanisms between poplar and Arabidopsis remains limited.In this study,we investigated the function of PagMYB128 during wood formation and found it had broader impacts on SCW formation compared to its Arabidopsis ortholog,AtMYB103.Transgenic poplar trees overexpressing PagMYB128 exhibited significantly enhanced xylem development,with fiber cells and vessels displaying thicker walls,and an increase in the levels of cellulose,lignin,and hemicelluloses in the wood.In contrast,plants with dominant repression of PagMYB128 demonstrated the opposite phenotypes.RNA sequencing and reverse transcription–quantitative polymerase chain reaction showed that PagMYB128 could activate SCW biosynthetic gene expression,and chromatin immunoprecipitation along with yeast one-hybrid,and effector–reporter assays showed this regulation was direct.Further analysis revealed that PagSND1(SECONDARY WALL-ASSOCIATED NAC-DOMAIN PROTEIN1)directly regulates PagMYB128 but not cell wall metabolic genes,highlighting the pivotal role of PagMYB128 in the SND1-driven regulatory network for wood development,thereby creating a feedforward loop in SCW biosynthesis.

关 键 词：cellulose HEMICELLULOSE LIGNIN PagMYB128 POPULUS transcription factor wood formation 

分 类 号：S792.11[农业科学—林木遗传育种]