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Plant Cell：木质部导管发育中支撑细胞壁模式建成的两个互补机制

已有 5349 次阅读 2017-9-28 11:19 |个人分类:每日摘要|系统分类:论文交流

Two Complementary Mechanisms Underpin Cell Wall Patterning during Xylem Vessel Development

First author:Rene Schneider; Affiliations: University of Melbourne (墨尔本大学): Parkville, Australia

Corresponding author: Staffan Persson

The evolution of the plant vasculature (维管) was essential for the emergence of terrestrial life. Xylem vessels (木质部导管) are solute-transporting (溶质运输) elements in the vasculature that possess secondary wall thickenings (次生壁加厚) deposited in intricate (复杂的) patterns. Evenly dispersed microtubule (MT; 微管) bands support the formation of these wall thickenings, but how the MTs direct cell wall synthesis during this process remains largely unknown. Cellulose (纤维素) is the major secondary wall constituent (组成) and is synthesized by plasma membrane(质膜)-localized cellulose synthases (CesAs) whose catalytic activity propels (驱动) them through the membrane. We show that the protein CELLULOSE SYNTHASE INTERACTING (CSI)1/POM2 is necessary to align the secondary wall CesAs and MTs during the initial phase of xylem vessel development in Arabidopsis thaliana and Oryza sativa (rice). Surprisingly, these MT-driven patterns successively become imprinted and sufficient to sustain the continued progression of wall thickening in the absence of MTs and CSI1/POM2 function. Hence, two complementary principles underpin (支撑) wall patterning during xylem vessel development.

植物维管系统的进化对于地表生物的出现是必要的。木质部导管是维管系统中负责溶质运输的组分，并通过复杂的模式来参与植物次生壁的加厚。甚至于分散的微管（MTs）也会有助于这些次生壁的加厚，但微管如何直接参与细胞壁的合成还不清楚。纤维素是细胞壁组成的主要成分，由定位于质膜的纤维素合酶（CesAs）所合成，且CesAs的酶活会驱动合成后的纤维素通过膜。本研究显示纤维素合酶的相互作用因子CSI1/POM2在拟南芥和水稻木质部导管发育起始时细胞壁CesAs和MTs的排列过程中起作用。有趣的是，这些MT所驱动的模式会在缺失MTs和CSI1/POM2功能后继续维持细胞壁加厚过程持续下去。因此，两个相互互补的机制在木质部导管发育中支撑着细胞壁的模式建成。

通讯：Staffan Persson (https://findanexpert.unimelb.edu.au/display/person658388)