Suo Bangxia, Seifert Stephanie, Kirik Viktor
School of Biological Sciences, Illinois State University, Normal, IL 61790, USA.
J Exp Bot. 2013 Nov;64(16):4981-91. doi: 10.1093/jxb/ert287. Epub 2013 Sep 7.
Specialized plant cells form cell walls with distinct composition and properties pertinent to their function. Leaf trichomes in Arabidopsis form thick cell walls that support the upright growth of these large cells and, curiously, have strong light-reflective properties. To understand the process of trichome cell-wall maturation and the molecular origins of this optical property, mutants affected in trichome light reflection were isolated and characterized. It was found that GLASSY HAIR (GLH) genes are required for the formation of surface papillae structures at late stages of trichome development. Trichomes in these mutants appeared transparent due to unobstructed light transmission. Genetic analysis of the isolated mutants revealed seven different gene loci. Two--TRICHOME BIREFRINGENCE (TBR) and NOK (Noeck)--have been reported previously to have the glassy trichome mutant phenotype. The other five glh mutants were analysed for cell-wall-related phenotypes. A significant reduction was found in cellulose content in glh2 and glh4 mutant trichomes. In addition to the glassy trichome phenotype, the glh6 mutants showed defects in leaf cuticular wax, and glh6 was found to represent a new allele of the eceriferum 10 (cer10) mutation. Trichomes of the glh1 and glh3 mutants did not show any other phenotypes beside reduced papillae formation. These data suggest that the GLH1 and GLH3 genes may have specific functions in trichome papillae formation, whereas GLH2, GLH4, and GLH6 genes are also involved in deposition of other cell-wall components.
特化的植物细胞形成具有与其功能相关的独特组成和特性的细胞壁。拟南芥的叶毛形成厚细胞壁，支撑这些大型细胞的直立生长，并且奇怪的是，具有很强的光反射特性。为了了解毛状体细胞壁成熟过程以及这种光学特性的分子起源，分离并鉴定了影响毛状体光反射的突变体。发现玻璃毛（GLH）基因是毛状体发育后期表面乳头结构形成所必需的。由于光透射无阻，这些突变体中的毛状体显得透明。对分离出的突变体的遗传分析揭示了七个不同的基因位点。其中两个——毛状体双折射（TBR）和NOK（Noeck）——先前已报道具有玻璃状毛状体突变体表型。对其他五个glh突变体进行了细胞壁相关表型分析。发现glh2和glh4突变体毛状体中的纤维素含量显著降低。除了玻璃状毛状体表型外，glh6突变体在叶片表皮蜡质方面存在缺陷，并且发现glh6代表蜡质缺乏10（cer10）突变的一个新等位基因。glh1和glh3突变体的毛状体除了乳头形成减少外，没有表现出任何其他表型。这些数据表明，GLH1和GLH3基因可能在毛状体乳头形成中具有特定功能，而GLH2、GLH4和GLH6基因也参与其他细胞壁成分的沉积。
