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Front. Plant Sci. | doi: 10.3389/fpls.2018.01262

Ectopic Expression of PtoMYB74 in Poplar and Arabidopsis Promotes Secondary Cell Wall Formation

  • 1Southwest University, China
  • 2Northwest Institute of Plateau Biology, China

In higher plants, R2R3-MYB transcription factors are important regulators of secondary cell wall formation. Although 192 annotated R2R3 MYB genes were identified in poplar genome, only a few members were characterized to participate in the regulation of secondary cell wall biosynthesis. In this paper, we identify a R2R3-MYB transcription factor, PtoMYB74, which is predicted to be an orthologue of Arabidopsis AtMYB61, a transcription activator that regulates secondary cell wall formation, lignin biosynthesis, stomatal aperture and the mucilage of seed coat. PtoMYB74 is mainly expressed in stems, especially in the xylem tissues and organs. PtoMYB74 as a transcriptional activator is localized to the nucleus. The overexpression of PtoMYB74 increased the secondary cell wall thickness of vessels in transgenic poplar and changed secondary cell wall compositions. The expression levels of lignin and cellulose biosynthetic genes were elevated in transgenic poplar overexpressing PtoMYB74 compared to the wild type, while xylan biosynthetic genes were not changed. Transcriptional activation assays demonstrated that PtoMYB74 could activate the promoters of structural genes in lignin and cellulose biosynthetic pathways. Taken together, our data show that PtoMYB74 positively regulates secondary cell wall biosynthesis in poplar.

Keywords: Populus, secondar cell wall, MYB, Transcription, Genetic, transgenic

Received: 04 Feb 2018; Accepted: 10 Aug 2018.

Edited by:

Shucai Wang, Northeast Normal University, China

Reviewed by:

Hua Cassan Wang, Université de Toulouse, France
Guohua Chai, Qingdao Institute of Bioenergy and Bioprocess Technology (CAS), China  

Copyright: © 2018 Luo, Ma and Li. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Keming Luo, Southwest University, Chongqing, China, luokeming@hotmail.com