The Arabidopsis root hair cell wall formation mutant lrx1 is suppressed by mutations in the RHM1 gene encoding a UDP-L-rhamnose synthase
The Arabidopsis root hair cell wall formation mutant lrx1 is suppressed by mutations in the RHM1 gene encoding a UDP-L-rhamnose synthase
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DOI：
10.1105/tpc.105.038653
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发表时间：
2006-07-01
期刊：
影响因子：
11.6
通讯作者：
Ringli, Christoph
中科院分区：
文献类型：
--
作者：
Diet, Anouck;Link, Bruce;Ringli, Christoph
细胞和细胞壁生长是相互依赖的过程，必须紧密协调和控制。拟南芥LRR-延伸蛋白1（LRX 1）是一种潜在的细胞壁发育调控因子，由N端富含亮氨酸的重复序列结构域和C端延伸蛋白样结构域组成。LRX 1在根毛中表达，Irx 1突变体植物产生扭曲的根毛，通常膨胀、分支或塌陷。在Irx 1突变体中发现的异常细胞壁结构指向LRX 1在细胞外基质建立过程中的功能。为了鉴定参与LRX 1依赖性发育途径的基因，对Irx 1突变体进行了抑制筛选，并分离出两个独立的rol 1（Irx 1的抑制物）等位基因。ROL 1是鼠李糖生物合成1的等位基因，鼠李糖生物合成1编码参与鼠李糖生物合成的蛋白质，鼠李糖是果胶的主要单糖组分。rol 1突变修饰果胶多糖鼠李糖半乳糖醛酸聚糖I，对于一个等位基因，修饰鼠李糖半乳糖醛酸聚糖II。此外，rol 1突变引起许多细胞壁相关基因表达的变化。因此，Irx 1突变体表型很可能被果胶多糖或其他细胞壁成分的变化所抑制。
Cell and cell wall growth are mutually dependent processes that must be tightly coordinated and controlled. LRR-extensin1 (LRX1) of Arabidopsis thaliana is a potential regulator of cell wall development, consisting of an N-terminal leucine-rich repeat domain and a C-terminal extensin-like domain typical for structural cell wall proteins. LRX1 is expressed in root hairs, and Irx1 mutant plants develop distorted root hairs that often swell, branch, or collapse. The aberrant cell wall structures found in Irx1 mutants point toward a function of LRX1 during the establishment of the extracellular matrix. To identify genes that are involved in an LRX1-dependent developmental pathway, a suppressor screen was performed on the Irx1 mutant, and two independent rol1 (for repressor of Irx1) alleles were isolated. ROL1 is allelic to Rhamnose Biosynthesis1, which codes for a protein involved in the biosynthesis of rhamnose, a major monosaccharide component of pectin. The rol1 mutations modify the pectic polysaccharide rhamnogalacturonan I and, for one allele, rhamnogalacturonan II. Furthermore, the rol1 mutations cause a change in the expression of a number of cell wall-related genes. Thus, the Irx1 mutant phenotype is likely to be suppressed by changes in pectic polysaccharides or other cell wall components.