Molecular studies of cellulose synthase supercomplex from cotton fiber reveal its unique biochemical properties  

作　　者：Xingpeng Wen Yufeng Zhai Li Zhang Yanjun Chen Zhiyuan Zhu Gang Chen Kun Wang Yuxian Zhu 

机构地区：[1]Institute for Advanced Studies,Wuhan University,Wuhan 430072,China [2]Hubei Hongshan Laboratory,Wuhan 430070,China [3]College of Life Sciences,Wuhan University,Wuhan 430072,China [4]School of Physical Science and Technology,ShanghaiTech University,Shanghai 201210,China

出　　处：《Science China(Life Sciences)》2022年第9期1776-1793,共18页中国科学（生命科学英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(31690090,31690091,31830057,32070207);the Foundation of Hubei Hongshan Laboratory(2021hszd014).

摘　　要：Cotton fiber is a highly elongated and thickened single cell that produces large quantities of cellulose,which is synthesized and assembled into cell wall microfibrils by the cellulose synthase complex(CSC).In this study,we report that in cotton(Gossypium hirsutum)fibers harvested during secondary cell wall(SCW)synthesis,GhCesA 4,7,and 8 assembled into heteromers in a previously uncharacterized 36-mer-like cellulose synthase supercomplex(CSS).This super CSC was observed in samples prepared using cotton fiber cells harvested during the SCW synthesis period but not from cotton stem tissue or any samples obtained from Arabidopsis.Knock-out of any of GhCesA 4,7,and 8 resulted in the disappearance of the CSS and the production of fiber cells with no SCW thickening.Cotton fiber CSS showed significantly higher enzyme activity than samples prepared from knock-out cotton lines.We found that the microfibrils from the SCW of wild-type cotton fibers may contain 72 glucan chains in a bundle,unlike other plant materials studied.GhCesA4,7,and 8 restored both the dwarf and reduced vascular bundle phenotypes of their orthologous Arabidopsis mutants,potentially by reforming the CSC hexamers.Genetic complementation was not observed when non-orthologous CesA genes were used,indicating that each of the three subunits is indispensable for CSC formation and for full cellulose synthase function.Characterization of cotton CSS will increase our understanding of the regulation of SCW biosynthesis.

关 键 词：cotton fiber cellulose synthase supercomplex(CSS) GhCesA 36-mer-like SCW 72 chain model microfibril 

分 类 号：Q94[生物学—植物学]