Isolation of a novel cell wall architecture mutant of rice with defective Arabidopsis COBL4 ortholog BC1 required for regulated deposition of secondary cell wall components
Isolation of a novel cell wall architecture mutant of rice with defective Arabidopsis COBL4 ortholog BC1 required for regulated deposition of secondary cell wall components
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DOI：
10.1007/s00425-010-1171-4
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发表时间：
2010-06-01
期刊：
影响因子：
4.3
通讯作者：
Katayama, Yoshihiro
中科院分区：
文献类型：
--
作者：
Sato, Kanna;Suzuki, Ryu;Katayama, Yoshihiro
植物次生细胞壁是由各种多糖、酚类物质和蛋白质组成的高度有序的结构。它的协调调节许多复杂的代谢途径和组装尚未解决。为了了解调控次生细胞壁合成的分子机制，我们分离了一个新的水稻突变体，细胞壁结构1（cwa 1），表现出不规则增厚的厚壁组织的次生细胞壁，以及秆脆和成熟节间纤维素含量减少。光学和透射电子显微镜显示，cwa 1突变体植物在其节间皮层纤维的次生细胞壁中具有局部聚集区域，显示出不均匀的厚度。紫外显微镜观察表明，细胞壁酚类成分的定位受到干扰，这些成分大量沉积在厚壁组织的聚集细胞壁区域。因此，次生细胞壁物质，即酚类成分的沉积和组装的调节似乎受到cwa 1基因突变的干扰。遗传分析表明，cwa 1与brickculm 1（bc 1）等位，后者编码植物中特异性的糖基磷脂酰肌醇锚定的COBRA-like蛋白。BC 1被认为是一种调节因子，控制着茎的机械强度和厚壁组织次生细胞壁中的纤维素含量，但BC 1的确切功能尚未得到解决。我们的研究结果表明，CWA 1/BC 1在组装细胞壁成分在其适当的网站，从而使固体和灵活的节间在水稻的合成中具有重要的作用。
The plant secondary cell wall is a highly ordered structure composed of various polysaccharides, phenolic components and proteins. Its coordinated regulation of a number of complex metabolic pathways and assembly has not been resolved. To understand the molecular mechanisms that regulate secondary cell wall synthesis, we isolated a novel rice mutant, cell wall architecture1 (cwa1), that exhibits an irregular thickening pattern in the secondary cell wall of sclerenchyma, as well as culm brittleness and reduced cellulose content in mature internodes. Light and transmission electron microscopy revealed that the cwa1 mutant plant has regions of local aggregation in the secondary cell walls of the cortical fibers in its internodes, showing uneven thickness. Ultraviolet microscopic observation indicated that localization of cell wall phenolic components was perturbed and that these components abundantly deposited at the aggregated cell wall regions in sclerenchyma. Therefore, regulation of deposition and assembly of secondary cell wall materials, i.e. phenolic components, appear to be disturbed by mutation of the cwa1 gene. Genetic analysis showed that cwa1 is allelic to brittle culm1 (bc1), which encodes the glycosylphosphatidylinositol-anchored COBRA-like protein specifically in plants. BC1 is known as a regulator that controls the culm mechanical strength and cellulose content in the secondary cell walls of sclerenchyma, but the precise function of BC1 has not been resolved. Our results suggest that CWA1/BC1 has an essential role in assembling cell wall constituents at their appropriate sites, thereby enabling synthesis of solid and flexible internodes in rice.