文献类型： 外文期刊

作者： He, Jun-Bo ¹ ; Zhao, Xian-Hai ¹ ; Du, Ping-Zhou ³ ; Zeng, Wei ⁴ ; Beahan, Cherie T. ⁴ ; Wang, Yu-Qi ³ ; Li, Hui-Ling ¹ ;

作者机构： 1.South China Agr Univ, State Key Lab Conservat & Utilizat Subtrop Agrobi, Guangzhou 510642, Guangdong, Peoples R China

2.South China Agr Univ, Coll Forestry & Landscape Architecture, Guangdong Key Lab Innovat Dev & Utilizat Forest P, Guangzhou 510642, Guangdong, Peoples R China

3.South China Agr Univ, Coll Life Sci, Guangzhou 510642, Guangdong, Peoples R China

4.Univ Melbourne, Sch BioSci, ARC Ctr Excellence Plant Cell Walls, Parkville, Vic 3010, Australia

5.Boyce Thompson Inst Plant Res, Ithaca, NY 14853 USA

6.Jiangsu Acad Agr Sci, Prov Key Lab Agrobiol, Nanjing 210014, Jiangsu, Peoples R China

7.Beijing Normal Univ, Coll Life Sci, Minist Educ, Key Lab Cell Proliferat & Regulat Biol, Beijing 100875, Peoples R China

期刊名称：JOURNAL OF INTEGRATIVE PLANT BIOLOGY （ 影响因子：7.061； 五年影响因子：6.002 ）

ISSN： 1672-9072

年卷期： 2018 年 60 卷 6 期

页码：

收录情况： SCI

摘要： Xylan is the major plant hemicellulosic polysaccharide in the secondary cell wall. The transcription factor KNOTTED-LIKE HOMEOBOX OF ARABIDOPSIS THALIANA 7 (KNAT7) regulates secondary cell wall biosynthesis, but its exact role in regulating xylan biosynthesis remains unclear. Using transactivation analyses, we demonstrate that KNAT7 activates the promoters of the xylan biosynthetic genes, IRREGULAR XYLEM 9 (IRX9), IRX10, IRREGULAR XYLEM 14-LIKE (IRX14L), and FRAGILE FIBER 8 (FRA8). The knat7 T-DNA insertion mutants have thinner vessel element walls and xylary fibers, and thicker interfascicular fiber walls in inflorescence stems, relative to wild-type (WT). KNAT7 overexpression plants exhibited opposite effects. Glycosyl linkage and sugar composition analyses revealed lower xylan levels in knat7 inflorescence stems, relative to WT; a finding supported by labeling of inflorescence walls with xylan-specific antibodies. The knat7 loss-of-function mutants had lower transcript levels of the xylan biosynthetic genes IRX9, IRX10, and FRA8, whereas KNAT7 overexpression plants had higher mRNA levels for IRX9, IRX10, IRX14L, and FRA8. Electrophoretic mobility shift assays indicated that KNAT7 binds to the IRX9 promoter. These results support the hypothesis that KNAT7 positively regulates xylan biosynthesis.