Bark storage protein overexpression promotes plant growth and inhibits lignin biosynthesis in poplar
Hao Hu1, Guofen Su1, Wutao Zhang1
1Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi Colleges and Universities Key Laboratory for Cultivation and Utilization of Subtropical Forest Plantation, College of Forestry, Guangxi University, Nanning 530004, China; Key Laboratory of National Forestry and Grassland Administration on Cultivation of Fast-Growing Timber in Central South China, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Nanning 530004, China.
Abstract:
Secondary xylem development is crucial for perennial stem growth, wood production, and carbon sequestration in trees. However, the complex mechanisms underlying xylem development have not yet been fully elucidated. The present study demonstrated that the overexpression of two genes encoding the bark storage protein (BSP) from Jatropha curcas (JcBSP1) and Populus tomentosa (PtoBSPa) in P. tomentosa significantly enhanced plant growth, including plant height, stem diameter, and internode number. BSP overexpression promoted secondary stem growth by stimulating xylem formation. Additionally, compared to wild-type controls, BSP overexpression increased wood yield while reducing lignin content. Transcriptome analysis of stems revealed that BSP overexpression upregulated genes involved in xylem differentiation, but downregulated genes related to secondary cell wall formation. In summary, these results suggest that BSPs are promising candidate genes for forest genetic engineering aiming to develop fast-growing trees with increased biomass yield and a low lignin content.
