The TUMOROUS SHOOT DEVELOPMENT2 gene of Arabidopsis encoding a putative methyltransferase is required for cell adhesion and co-ordinated plant development
The TUMOROUS SHOOT DEVELOPMENT2 gene of Arabidopsis encoding a putative methyltransferase is required for cell adhesion and co-ordinated plant development
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DOI：
10.1111/j.1365-313x.2007.03123.x
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发表时间：
2007-05-01
期刊：
影响因子：
7.2
通讯作者：
Schmuelling, Thomas
中科院分区：
文献类型：
--
作者：
Krupkova, Eva;Immerzeel, Peter;Schmuelling, Thomas
肿瘤枝条发育基因2(TSD2)的突变会减少细胞黏附，在强烈感染的个体中会导致枝条发育不协调，从而导致体外无序的肿瘤样生长。突变体tsd2的轴分生组织活性增强，根生长减慢，脱黄化增强。在突变背景中，茎分生组织标记基因KNA1和KNA2的表达区域扩大。土壤栽培的tsd2突变体相形见绌，但总体上表现出与野生型(WT)相似的形态。用图位克隆的方法对TSD2基因进行鉴定。该基因编码一个由684个氨基酸组成的多肽，N端有一个跨膜区，C端有S-腺苷-L-蛋氨酸结合区和甲基转移酶结构域。TSD2：GUS报告基因主要在分生组织和幼嫩组织中表达。绿色荧光蛋白标记的TSD2蛋白定位于高尔基体。细胞黏附缺陷表明果胶性质改变，我们假设TSD2起果胶甲基转移酶的作用。然而，细胞壁组成分析表明，TSD2和WT在单糖组成、糖醛酸含量和果胶甲酯化总体程度上没有显著差异。这些发现支持TSD2作为甲基转移酶的功能，在细胞黏附和植物协调发展中发挥重要作用。
Mutations in the TUMOROUS SHOOT DEVELOPMENT2 (TSD2) gene reduce cell adhesion, and in strongly affected individuals cause non-coordinated shoot development that leads to disorganized tumor-like growth in vitro. tsd2 mutants showed increased activity of axial meristems, reduced root growth and enhanced de-etiolation. The expression domains of the shoot meristem marker genes KNAT1 and KNAT2 were enlarged in the mutant background. Soil-grown tsd2 mutants were dwarfed, but overall showed morphology similar to that of the wild-type (WT). The TSD2 gene was identified by map-based cloning. It encodes a novel 684 amino acid polypeptide containing a single membrane-spanning domain in the N-terminal part and S-adenosyl-L-methionine binding and methyltransferase domains in the C-terminal part. Expression of a TSD2:GUS reporter gene was detected mainly in meristems and young tissues. A green fluorescent protein-tagged TSD2 protein localized to the Golgi apparatus. The cell-adhesion defects indicated altered pectin properties, and we hypothesize that TSD2 acts as a pectin methyltransferase. However, analyses of the cell-wall composition revealed no significant differences of the monosaccharide composition, the uronic acid content and the overall degree of pectin methylesterification between tsd2 and WT. The findings support a function of TSD2 as a methyltransferase, with an essential role in cell adhesion and coordinated plant development.