Characterization of a xyloglucan endotransglucosylase gene that is up-regulated by gibberellin in rice
Characterization of a xyloglucan endotransglucosylase gene that is up-regulated by gibberellin in rice
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DOI：
10.1104/pp.104.052274
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发表时间：
2004-11-01
期刊：
影响因子：
7.4
通讯作者：
Komatsu, S
中科院分区：
文献类型：
--
作者：
Jan, A;Yang, GX;Komatsu, S
木葡聚糖内切转葡糖基酶/水解酶（XTH）介导初生细胞壁的β（1-4）-木葡聚糖的切割和重新连接，被认为在木葡聚糖交联的构建和重构中起重要作用。通过基因芯片分析赤霉素诱导的水稻幼苗基因表达变化，克隆并鉴定了一个新的水稻XTH相关基因OsXTH 8。OsXTH 8基因为单拷贝基因，全长cDNA为1，298 bp，编码290个氨基酸。系统发育分析表明，OsXTH 8福尔斯不属于XTH相关基因的三个亚家族。OsXTH 8在水稻叶鞘中优先表达，响应赤霉素。原位杂交和OsXTH 8启动子GUS融合分析表明，OsXTH 8在叶鞘和幼节根的维管束中高表达，其中细胞正在积极进行伸长和分化。OsXTH 8基因表达受赤霉酸的上调，其他激素的影响很小。在两个水稻高度异常突变体中，OsXTH 8的表达量与突变体的高度呈正相关。表达OsXTH 8的RNAi构建体的转基因水稻表现出抑制生长。这些结果表明OsXTH 8在水稻叶鞘中的差异表达与赤霉素有关，并可能参与细胞伸长过程。
Xyloglucan endotransglucosylases/hydrolases (XTHs) that mediate cleavage and rejoining of the beta (1-4)-xyloglucans of the primary cell wall are considered to play an important role in the construction and restructuring of xyloglucan cross-links. A novel rice (Oryza saliva) XTH-related gene, OsXTH8, was cloned and characterized after being identified by cDNA microarray analysis of gibberellin-induced changes in gene expression in rice seedlings. OsXTH8 was a single copy gene; its full-length cDNA was 1,298 bp encoding a predicted protein of 290 amino acids. Phylogenetic analysis revealed that OsXTH8 falls outside of the three established subfamilies of XTH-related genes. OsXTH8 was preferentially expressed in rice leaf sheath in response to gibberellic acid. In situ hybridization and OsXTH8 promoter GUS fusion analysis revealed that OsXTH8 was highly expressed in vascular bundles of leaf sheath and young nodal roots where the cells are actively undergoing elongation and differentiation. OsXTH8 gene expression was up-regulated by gibberellic acid and there was very little effect of other hormones. In two genetic mutants of rice with abnormal height, the expression of OsXTH8 positively correlated with the height of the mutants. Transgenic rice expressing an RNAi construct of OsXTH8 exhibited repressed growth. These results indicate that OsXTH8 is differentially expressed in rice leaf sheath in relation to gibberellin and potentially involved in cell elongation processes.