厌氧诱导木葡聚糖转葡糖苷酶(XET)基因在芝麻和小麦根中的表达  

Anaerobic Inducible Expression of Xyloglucan Endotransglycosylase (XET ) Gene in Sesame and Wheat Roots

作　　者：王文泉[1] 郑永战[2] 梅鸿献[2] 张劲松[3] 张福锁[1] 

机构地区：[1]中国农业大学植物营养系 [2]河南省农业科学院棉花油料作物研究所,郑州450002 [3]中国科学院遗传与发育生物学研究所,北京100101

出　　处：《农业生物技术学报》2004年第3期258-263,共6页Journal of Agricultural Biotechnology

基　　金：国家重点基础研究发展规划(973)项目(No.G1999011707)资助

摘　　要：木葡聚糖转葡糖苷酶(xyloglucan endotransglycosylase，XET)是一个新的细胞壁代谢关键酶。根据玉米(Zeamays)、大豆(Glycinemax)和番茄(Lycopersicon esculentum)XET基因保守区序列设计简并引物，采用RT-PCR从水稻(Oryzasativa)和厌氧处理的芝麻(Sesamum indicum)、小麦(Triticum aestivum)根中均获得494bp的cDNA片段，分别命名为OsXET、SiXET和TaXET。经同源分析，三者之间的相似性高达98．6％～99．2％，与基因库中玉米和拟南芥(Arabidopsis thaliana)的相似性在40．3％～54．9％。Southern杂交结果表明，芝麻和小麦中XET基因为单拷贝或低拷贝数。差异表达PCR分析表明，XET在强耐渍的野生芝麻和水稻根中为组成型表达，在耐渍的芝麻品种和马卡小麦根中随厌氧处理时间进程表达量增强，而在非耐渍芝麻根中无表达或者表达量很低。结合前期有关根结构和生理研究表明，XET在芝麻和小麦根中受厌氧诱导表达，与根中内源乙烯增生以及根皮层通气组织形成具有同步性，为新的与结构适应相关的耐渍基因。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.

关 键 词：芝麻 小麦 表达 木葡聚糖转葡糖苷酶 基因 根 

分 类 号：Q943.2[生物学—植物学]