Synergistic interaction of the two paralogous Arabidopsis genes LRX1 and LRX2 in cell wall formation during root hair development
Synergistic interaction of the two paralogous Arabidopsis genes LRX1 and LRX2 in cell wall formation during root hair development
复制标题
DOI：
10.1046/j.1365-313x.2003.01784.x
复制
发表时间：
2003-07-01
期刊：
影响因子：
7.2
通讯作者：
Ringli, C
中科院分区：
文献类型：
--
作者：
Baumberger, N;Steiner, M;Ringli, C
LRR-延伸蛋白（LRX）是一类含有受体样结构域的细胞壁结构蛋白。拟南芥LRX 1的功能分析表明，它参与根毛的细胞形态建成。在这项工作中，我们研究了LRX 2，LRX 1的一个parasyngeal。LRX 2的表达主要存在于根中，并且响应于促进或抑制根毛形成的因子。通过表达截短的LRX 2和不同的LRX 1/LRX 2嵌合蛋白来测试LRX 1和LRX 2的功能。使用互补的lrx 1表型作为蛋白质功能的参数，我们的实验表明，LRX 1和LRX 2的功能相似，但显示出它们的活性差异。遗传分析表明，单个lrx 2突变体在根毛形态发生中没有表现出任何缺陷，但与lrx 1突变协同相互作用。LRX 1/LRX 2双突变体具有显著增强的LRX 1表型，导致根毛在其起始后不久频繁断裂。根毛细胞壁超微结构的透射电子显微镜（TEM）分析揭示了形成的嗜酸性聚集体内的墙壁，以及局部解体的壁结构中的双突变体，但不是在野生型植物。我们的研究结果表明，LRX 1和LRX 2在根毛形成中具有重叠的功能，并且它们可能通过促进细胞壁的适当发育来调节细胞形态发生。
LRR-extensins (LRX) form a family of structural cell wall proteins containing a receptor-like domain. The functional analysis of Arabidopsis LRX1 has shown that it is involved in cell morphogenesis of root hairs. In this work, we have studied LRX2 , a paralog of LRX1 . LRX2 expression is mainly found in roots and is responsive to factors promoting or repressing root hair formation. The function of LRX1 and LRX2 was tested by the expression of a truncated LRX2 and different LRX1/LRX2 chimaeric proteins. Using complementation of the lrx1 phenotype as the parameter for protein function, our experiments indicate that LRX1 and LRX2 are functionally similar but show differences in their activity. Genetic analysis revealed that single lrx2 mutants do not show any defect in root hair morphogenesis, but synergistically interact with the lrx1 mutation. lrx1/lrx2 double mutants have a significantly enhanced lrx1 phenotype, resulting in frequent rupture of the root hairs soon after their initiation. Analysis of the root hair cell wall ultrastructure by transmission electron microscopy (TEM) revealed the formation of osmophilic aggregates within the wall, as well as local disintegration of the wall structure in the double mutant, but not in wild-type plants. Our results indicate that LRX1 and LRX2 have overlapping functions in root hair formation, and that they likely regulate cell morphogenesis by promoting proper development of the cell wall.