J Syst Evol ›› 2022, Vol. 60 ›› Issue (1): 169-185.DOI: 10.1111/jse.12595

• Research Articles • Previous Articles     Next Articles

Functional divergence of Populus MYB158 and MYB189 gene pair created by whole genome duplication

Peng-Fei Jiang1,2, Hui Xu1,2, Chao-Nan Guan3,4, Xiao-Xia Wang3,4, Ai-Min Wu5, Yan-Jing Liu3, and Qing-Yin Zeng3*   

  1. 1 State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
    2 University of Chinese Academy of Sciences, Beijing 100049, China
    3 State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing 100091, China
    4 College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
    5 Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China

    *Author for correspondence. E‐mail: qingyin.zeng@ibcas.ac.cn
  • Received:2020-02-28 Accepted:2020-04-23 Online:2020-04-27 Published:2022-01-01

Abstract: Whole genome duplication (WGD) provides new genetic material for genome evolution. After a WGD event, some duplicates are lost, while other duplicates still persist and evolve diverse functions. A particular challenge is to understand how this diversity arises. This study identified two WGD-derived duplicates, MYB158 and MYB189, from Populus tomentosa. Populus MYB158 and MYB189 had expression divergence. Populus tomentosa overexpressing MYB158 or MYB189 had similar phenotypes: creep growth, decreased width of xylem and secondary cell wall thickness. Compared to wild-type, neither myb158 mutant nor myb158 myb189 double mutant showed obvious phenotypic variation in P. tomentosa. Although MYB158 and MYB189 proteins could repress the same structural genes involved in lignin, cellulose, and xylan biosynthesis, the two proteins had their own specific regulatory targets. Populus MYB158 could act as the upstream regulator of secondary cell wall NAC master switch and directly represses the expression of the SND1-B2 gene. Taken together, Populus MYB158 and MYB189 have retained similar functions in negatively regulating secondary cell wall biosynthesis, but have evolved partially distinct functions in direct regulation of NAC master switch, with MYB158 playing a more crucial role. Our findings provide new insights into the evolutionary and functional divergence of WGD-derived duplicate genes.

Key words: duplicate gene, functional divergence, MYB transcription factor, regulatory networks, secondary cell wall biosynthesis, whole genome duplication