College of Life Sciences, Zhejiang University, 866 Yu Hang tang Road, Hangzhou, 310058, China.
State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China.
New Phytol. 2020 Feb;225(4):1516-1530. doi: 10.1111/nph.15936. Epub 2019 Jul 2.
Brassinosteroids have been implicated in the differentiation of vascular cell types in herbaceous plants, but their roles during secondary growth and wood formation are not well defined. Here we pharmacologically and genetically manipulated brassinosteroid levels in poplar trees and assayed the effects on secondary growth and wood formation, and on gene expression within stems. Elevated brassinosteroid levels resulted in increases in secondary growth and tension wood formation, while inhibition of brassinosteroid synthesis resulted in decreased growth and secondary vascular differentiation. Analysis of gene expression showed that brassinosteroid action is positively associated with genes involved in cell differentiation and cell-wall biosynthesis. The results presented here show that brassinosteroids play a foundational role in the regulation of secondary growth and wood formation, in part through the regulation of cell differentiation and secondary cell wall biosynthesis.
油菜素内酯被认为参与了草本植物血管细胞类型的分化，但它们在次生生长和木材形成中的作用尚未明确界定。在这里，我们通过药理学和遗传学手段操纵杨树中的油菜素内酯水平，并检测其对次生生长和木材形成以及茎内基因表达的影响。油菜素内酯水平升高会导致次生生长和张力木形成增加，而油菜素内酯合成的抑制则会导致生长和次生维管束分化减少。基因表达分析表明，油菜素内酯的作用与参与细胞分化和细胞壁生物合成的基因呈正相关。本研究结果表明，油菜素内酯在调节次生生长和木材形成中起着基础性作用，部分是通过调节细胞分化和次生细胞壁生物合成来实现的。
