文献类型：期刊文献

英文题名：PagKNAT2/6b regulates tension wood formation and gravitropism by targeting cytokinin metabolism

作者：Hu, Mengxuan[1] Zhao, Shutang[1,2] Zhao, Yanqiu[1,3] Lu, Mengzhu[1,2,4] Song, Xueqin[1,2]

第一作者：Hu, Mengxuan

通信作者：Song, XQ[1]

机构：[1]Chinese Acad Forestry, Res Inst Forestry, State Key Lab Tree Genet & Breeding, Key Lab Tree Breeding & Cultivat,State Forestry Ad, Xiangshan Rd, Beijing 100091, Peoples R China;[2]Nanjing Forestry Univ, Coinnovat Ctr Sustainable Forestry Southern China, Longpan Rd, Nanjing 210037, Jiangsu, Peoples R China;[3]Ludong Univ, Sch Agr, Hongqizhong Rd, Yantai 264025, Peoples R China;[4]Zhejiang Agr & Forestry Univ, Sch Forestry & Biotechnol, State Key Lab Subtrop Silviculture, Wusu St, Hangzhou 311300, Peoples R China

年份：2024

卷号：44

期号：8

外文期刊名：TREE PHYSIOLOGY

收录：;Scopus(收录号：2-s2.0-85201725350);WOS:【SCI-EXPANDED(收录号:WOS:001292104100001)】；

基金：This work was supported by the National Key Research and Development Program of China (2019YFE0119100), and the National Natural Science Foundation of China (32171812 and 32101482).

语种：英文

外文关键词：gravity; growth; hormone; IPT; KNOX; Populus

摘要：Tension wood is a specialized xylem tissue associated with gravitropism in angiosperm trees. However, few regulators of tension wood formation have been identified. The molecular mechanisms underpinning tension wood formation remain elusive. Here, we report that a Populus KNOTTED-like homeobox gene, PagKNAT2/6b, is involved in tension wood formation and gravity response. Transgenic poplar plants overexpressing PagKNAT2/6b displayed more sensitive gravitropism than controls, as indicated by increased stem curvature. Microscopic examination revealed greater abundance of fibre cells with a gelatinous cell wall layer (G-layer) and asymmetric growth of secondary xylem in PagKNAT2/6b overexpression lines. Conversely, PagKNAT2/6b dominant repression plants exhibited decreased tension wood formation and reduced response to gravity stimulation. Moreover, sensitivity to gravity stimulation showed a negative relationship with development stage. Expression of genes related to growth and senescence was affected in PagKNAT2/6b transgenic plants. More importantly, transcription activation and electrophoretic mobility shift assays suggested that PagKNAT2/6b promotes the expression of cytokinin metabolism genes. Consistently, cytokinin content was increased in PagKNAT2/6b overexpression plants. Therefore, PagKNAT2/6b is involved in gravitropism and tension wood formation, likely via modulation of cytokinin metabolism.