中文摘要：

胡杨是典型的抗旱树种。挖掘和鉴定胡杨的耐旱基因对于提高植物抗旱性具有重要意义。木葡聚糖内转糖苷酶/水解酶（XTH）是植物细胞壁重构过程中的关键酶,在植物逆境胁迫响应中发挥重要作用。我们前期已从胡杨叶片中克隆了Pe XTH基因。本文利用Real-time PCR检测Pe XTH基因在干旱胁迫下的表达水平。在此基础上,构建植物表达载体p MDC85-Pe XTH,通过农杆菌介导法将Pe XTH基因转入烟草,分析过表达Pe XTH基因烟草的抗旱性。研究发现,胡杨叶片中Pe XTH基因的表达受干旱胁迫诱导。干旱处理后,转Pe XTH基因烟草的萌发率明显高于野生型烟草;与野生型植株相比,转基因植株的叶片失水速率明显降低。干旱胁迫下,转基因烟草的气孔开度仅为野生型烟草的51.2%~53.6%。结果表明,过表达Pe XTH基因能够提高烟草的抗旱性。本研究丰富了对胡杨Pe XTH基因功能的认识,为植物抗旱分子育种提供了重要的基因资源。

英文摘要：

Populus euphratica is a typical drought-tolerant tree.Therefore the exploration and identification of drought tolerance-related genes in P.euphratica is of great significance for the improvement of drought resistance of plants.Xyloglucan endotransglucosylase/hydrolase（XTH） is considered as a vital enzyme controlling plant cell wall modification.XTH plays important role in stress responses of plants.We had previously cloned a XTH gene from P.euphratica leaves.In the present study,expression level of the Pe XTH gene was detected by real-time PCR under drought condition.Meanwhile,a recombinant p MDC85-Pe XTH vector was constructed and then transferred into tobacco plants through Agrobacterium-mediated method.Drought tolerant characters of the transgenic tobacco lines were analyzed.Our results showed that the expression of Pe XTH could be induced by drought stress in P.euphratica leaves.Upon drought stress,Pe XTH-transgenic tobacco showed significantly higher germination ratio than that of wild-type tobacco.As compared to the wild-type plants,the transgenic plants revealed much lower water loss rate in leaves.Under drought condition,the stomatal aperture of transgenic tobacco was only 51.2% ~ 53.6% of that of the wild-type plants.These results indicated that overexpression of Pe XTH could enhance drought tolerance of tobacco.This study enriched our knowledge of the function of Pe XTH gene,and providing important gene resources for drought resistance breeding in plants.