Anaerobic Inducible Expression of Xyloglucan Endotransglycosylase (XET ) Gene in Sesame and Wheat Roots
Anaerobic Inducible Expression of Xyloglucan Endotransglycosylase (XET ) Gene in Sesame and Wheat Roots
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发表时间：
2004
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通讯作者：
W. Wen
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作者：
W. Wen
木葡聚糖内糖基转移酶（XET）是细胞壁代谢中的一种新型核心酶。利用设计的同源引物，通过RT-PCR方法分别从水稻（Oryza sativa）、芝麻（Sesamum indicum）和小麦（Triticum aestivum）的缺氧根中扩增得到XET基因的部分cDNA序列。它们分别命名为OsXET、SiXET和Ta-XET，均为494 bp。一级序列分析表明，3个克隆的同源性为98.6%~99.2%，与拟南芥和玉米的同源性为40.3%~54.9%。Southern杂交分析表明，XET基因在芝麻和小麦基因组中均存在1至数个拷贝。在耐涝性不同的基因型中的表达模式表明，在耐涝性最强的野生芝麻和水稻中，该基因在根中呈组成型表达;在耐涝性较弱的芝麻和小麦中，该基因在缺氧处理后表达量呈适应性增加;在耐涝性较差的芝麻中，该基因在根中不表达。结合前人对这些基因型根系结构和生理的研究结果，认为这是一个新的与结构适应有关的耐涝基因，在芝麻和小麦的根中，缺氧胁迫下可诱导产生内源乙烯和通气组织。
Xyloglucan endotransglycosylase (XET) is a novel core enzyme in metabolism of cell wall. The partial cDNA sequences of XET were obtained from root of rice (Oryza sativa ), sesame (Sesamum indicum ) and wheat (Triticum aestivum ) under anoxia condition respectively by RT-PCR amplification using designed homologous premiers. They were termed OsXET, SiXET and Ta-XET respectively and each had 494 bp. Primary sequence analysis indicated that the similarity was 98.6%~99.2% among the three clones, and was 40.3%~54.9% when were compared with those from Arabidopsis thaliana and Zea mays. Southern blotting analysis illustrated that there were about one to several copies of XET gene in the genome of sesame and wheat. Its expression patterns in genotypes with differential waterlogging tolerance showed that constitutive expression was observed in roots of wild sesame and rice with the best tolerance to flooding, and acclimated increasing expression was found in roots of flooding tolerance genotypes in sesame and wheat following to anoxia treat. However, no expression was detected in roots of sesame with less tolerance to waterlogging. Combining the former investigations on root structure and physiology of these genotypes with the present result, it's concluded that this is a novel waterlogging tolerance gene related to structural adaptation, and can be induced in roots of sesame and wheat under anoxia stress where endogenous ethylene production and formation of aerenchyma have been observed.