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A COBRA family protein, PtrCOB3, contributes to gelatinous layer formation of tension wood fibers in poplar.
Xu, Wenjing; Cheng, Hao; Cheng, Jiyao; Zhu, Siran; Cui, Yongyao; Wang, Chong; Wu, Jianzhen; Lan, Xingguo; Cheng, Yuxiang.
Afiliação
  • Xu W; State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China.
  • Cheng H; College of Life Sciences, Northeast Forestry University, Harbin 150040, China.
  • Cheng J; State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China.
  • Zhu S; State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China.
  • Cui Y; State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China.
  • Wang C; State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China.
  • Wu J; State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China.
  • Lan X; State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China.
  • Cheng Y; College of Life Sciences, Northeast Forestry University, Harbin 150040, China.
Plant Physiol ; 196(1): 323-337, 2024 Sep 02.
Article em En | MEDLINE | ID: mdl-38850037
ABSTRACT
Angiosperm trees usually develop tension wood (TW) in response to gravitational stimulation. TW comprises abundant gelatinous (G-) fibers with thick G-layers primarily composed of crystalline cellulose. Understanding the pivotal factors governing G-layer formation in TW fiber remains elusive. This study elucidates the role of a Populus trichocarpa COBRA family protein, PtrCOB3, in the G-layer formation of TW fibers. PtrCOB3 expression was upregulated, and its promoter activity was enhanced during TW formation. Comparative analysis with wild-type trees revealed that ptrcob3 mutants, mediated by Cas9/gRNA gene editing, were incapable of producing G-layers within TW fibers and showed severely impaired stem lift. Fluorescence immunolabeling data revealed a dearth of crystalline cellulose in the tertiary cell wall (TCW) of ptrcob3 TW fibers. The role of PtrCOB3 in G-layer formation is contingent upon its native promoter, as evidenced by the comparative phenotypic assessments of pCOB11PtrCOB3, pCOB3PtrCOB3, and pCOB3PtrCOB11 transgenic lines in the ptrcob3 background. Overexpression of PtrCOB3 under the control of its native promoter expedited G-layer formation within TW fibers. We further identified 3 transcription factors that bind to the PtrCOB3 promoter and positively regulate its transcriptional levels. Alongside the primary TCW synthesis genes, these findings enable the construction of a 2-layer transcriptional regulatory network for the G-layer formation of TW fibers. Overall, this study uncovers mechanistic insight into TW formation, whereby a specific COB protein executes the deposition of cellulose, and consequently, G-layer formation within TW fibers.
Assuntos

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Proteínas de Plantas / Madeira / Regulação da Expressão Gênica de Plantas / Populus Idioma: En Ano de publicação: 2024 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Proteínas de Plantas / Madeira / Regulação da Expressão Gênica de Plantas / Populus Idioma: En Ano de publicação: 2024 Tipo de documento: Article