PtoNAC90 is a positive regulator for secondary xylem development in Populus

Leiqian Sun; Peixuan Li; Xincaiyu Cui; Yawei Fan; Han Liu; YuPing Feng; Hui Li; Hai Lu

doi:10.1016/j.ijbiomac.2025.145803

PtoNAC90 is a positive regulator for secondary xylem development in Populus

Int J Biol Macromol. 2025 Jul 11:145803. doi: 10.1016/j.ijbiomac.2025.145803. Online ahead of print.

Authors

Leiqian Sun¹, Peixuan Li¹, Xincaiyu Cui¹, Yawei Fan¹, Han Liu¹, YuPing Feng¹, Hui Li², Hai Lu³

Affiliations

¹ State Key Laboratory of Tree Genetics and Breeding, National Engineering Research Center of Tree Breeding and Ecological Restoration, The Tree and Ornamental Plant Breeding and Biotechnology Laboratory of National Forestry and Grassland Administration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China.
² State Key Laboratory of Tree Genetics and Breeding, National Engineering Research Center of Tree Breeding and Ecological Restoration, The Tree and Ornamental Plant Breeding and Biotechnology Laboratory of National Forestry and Grassland Administration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China. Electronic address: lihui830@bjfu.edu.cn.
³ State Key Laboratory of Tree Genetics and Breeding, National Engineering Research Center of Tree Breeding and Ecological Restoration, The Tree and Ornamental Plant Breeding and Biotechnology Laboratory of National Forestry and Grassland Administration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China. Electronic address: luhai1974@bjfu.edu.cn.

PMID: 40653242
DOI: 10.1016/j.ijbiomac.2025.145803

Abstract

Secondary growth is regulated by numerous transcription factors under multi-level transcriptional control; however, only a few are considered as key regulators of secondary cell walls biosynthesis in Populus. This study identified PtoNAC90 as a transcription factor crucial for xylem development in Populus. PtoNAC90 is specifically expressed in developing xylem tissues. Compared to wild-type plants, transgenic Populus lines overexpressing PtoNAC90 display thickened xylem and enhanced secondary cell walls, demonstrating its positive regulatory role in xylem development. Interestingly, the lignin, cellulose, and hemicellulose content in the secondary walls of stem xylem exhibited distinct increases in PtoNAC90-overexpressing plants. Using electrophoretic mobility shift assay (EMSA) and luciferase reporter assays, we demonstrated that PtoNAC90 is directly activated by PtoWND1A. Furthermore, PtoNAC90 directly activates key secondary cell wall deposition genes, including PtoPAL3, PtoCesA6, and PtoCslA9. These findings demonstrate that PtoNAC90 positively regulates secondary cell wall formation and wood development, providing valuable insights into the molecular mechanisms controlling this process in trees.

Keywords: NAC transcription factor; Populus; PtoNAC90; Secondary cell wall.