Ectopic Expression of PtrLBD39 Retarded Primary and Secondary Growth in Populus trichocarpa

• Published in: International journal of molecular sciences Vol. 25; no. 4; p. 2205
• Main Authors: Yu, Jing, Gao, Boyuan, Li, Danning, Li, Shuang, Chiang, Vincent L, Li, Wei, Zhou, Chenguang
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 12.02.2024
• Subjects: Biosynthesis; Cell Wall - metabolism; Cellulose; Ectopic Gene Expression; Gene expression; Gene Expression Profiling; Gene Expression Regulation, Plant; Lignin; Metabolism; Metabolites; Plant growth; Plant Proteins - genetics; Plant Proteins - metabolism; Populus - metabolism; Populus trichocarpa; primary growth; Proteins; PtrLBD39; Scanning electron microscopy; secondary cell wall; Signal transduction; Transcription factors; Transcription Factors - genetics; Transcription Factors - metabolism; Transgenic plants; Wood - metabolism; wood formation; PtrLBD39; secondary cell wall; wood formation; Populus trichocarpa; primary growth
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms25042205

Primary and secondary growth of trees are needed for increments in plant height and stem diameter, respectively, affecting the production of woody biomass for applications in timber, pulp/paper, and related biomaterials. These two types of growth are believed to be both regulated by distinct transcription factor (TF)-mediated regulatory pathways. Notably, we identified PtrLBD39, a highly stem phloem-specific TF in and found that the ectopic expression of in markedly retarded both primary and secondary growth. In these overexpressing plants, the RNA-seq, ChIP-seq, and weighted gene co-expression network analysis (WGCNA) revealed that PtrLBD39 directly or indirectly regulates TFs governing vascular tissue development, wood formation, hormonal signaling pathways, and enzymes responsible for wood components. This regulation led to growth inhibition, decreased fibrocyte secondary cell wall thickness, and reduced wood production. Therefore, our study indicates that, following ectopic expression in , PtrLBD39 functions as a repressor influencing both primary and secondary growth.