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第一作者:Juan Du
第一单位:四川大学
通讯作者:Chaowen Xiaov
Abstract
背景回顾+问题:Pectins are abundant in the cell walls of dicotyledonous plants, but how they interact with other wall polymers and influence wall integrity and cell growth has remained mysterious.
主要发现:Here, we verified that QUASIMODO2 (QUA2) is a pectin methyltransferase and determined that QUA2 is required for normal pectin biosynthesis. 研究对象:To gain further insight into how pectin affects wall assembly and integrity maintenance, we investigated cellulose biosynthesis, cellulose organization, cortical microtubules, and wall integrity signaling in two mutant alleles of Arabidopsis thaliana QUA2, qua2 and tsd2. 结果1:In both mutants, crystalline cellulose content is reduced, cellulose synthase particles move more slowly, and cellulose organization is aberrant. 结果2:NMR analysis shows higher mobility of cellulose and matrix polysaccharides in the mutants. 结果3:Microtubules in mutant hypocotyls have aberrant organization, and depolymerize more readily upon treatment with oryzalin or external force. 结果4:The expression of genes related to wall integrity, wall biosynthesis, and microtubule stability is dis-regulated in both mutants. 结论:These data provide insights into how homogalacturonan is methylesterified upon its synthesis, the mechanisms by which pectin functionally interacts with cellulose, and how these interactions are translated into intracellular regulation to maintain the structural integrity of the cell wall during plant growth and development.
摘 要
果胶在双子叶植物的细胞壁中含量很高,但其如何与其它细胞壁多聚物互作并影响细胞壁完整性及细胞生长还在很大程度上是个谜团。本文中,作者证实了QUA2是一个果胶甲基转移酶,并确定果胶生物合成需要QUA2的参与。为了进一步了解果胶是如何影响细胞壁的组装和完整性维持,作者在拟南芥QUA2的两个等位基因突变体qua2和tsd2中,研究了纤维素生物合成、纤维素组织、皮质微管以及细胞壁完整性信号。在这两个突变体中,晶状纤维素含量降低,纤维素合酶颗粒运动更加缓慢,并且纤维素组织异常。NMR分析表明,纤维素和基质多糖在突变体中具有更高的流动性。突变型下胚轴中的微管组织异常,并且在用氨磺乐灵或外力处理后更加容易解聚。在两个突变体中,与细胞壁完整性、细胞壁生物合成以及微管稳定性有关的基因表达均失调。这些数据为同聚半乳糖醛酸在合成时如何被甲酯化的提供了新的视野,同时也揭示了果胶与纤维素功能性相互作用的机理以及这些相互作用如何转化为细胞内的调控,用以维持植物生长和发育过程中细胞壁的结构完整。
通讯作者
**肖朝文** 个人简介: 1998-2002年,四川农业大学,学士; 2002-2005年,四川农业大学,硕士; 2005-2009年,中国农业科学院,博士; 2009-2010年,芬兰赫尔辛基大学,博后; 2011-2017年,美国宾夕法尼亚州立大学,博后。 研究方向: 植物细胞壁合成与降解的分子机制; 植物细胞壁与细胞骨架的相互作用关系; 细胞壁完整性对植物生长发育的调控机理。
doi: 10.1105/tpc.20.00252
Journal: Plant Cell
First Published: September 03, 2020
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