小麦类甜蛋白基因的转化及转基因植株的抗病性分析

目前已克隆出许多类甜蛋白基因并成功转化马铃薯、水稻和小麦等植物，均可引起植株抗病性的提高。在以往的研究中我们从小麦中克隆了一个类甜蛋白基因(Ta-Tlp)，该基因在高抗白粉病的小麦6VS/6AL易位系中能够高水平表达，推测它与白粉病抗性密切相关。为进一步研究该基因的功能，本研究构建了包含在ubi强启动子控制下的Ta-Tlp基因的表达载体pAHC-TlP，用基因枪将其导入小麦品种扬麦158的幼胚愈伤组织，在含除草剂的选择培养基上经两轮筛选和分化，获得再生抗性植株。对T0、T1和T2代植株进行PCR、Southern杂交与RT-PCR分析，结果表明Ta-Tlp基因已整合进受体基因组并且能够表达。对T0代及其衍生的T1代(来自6个T0代阳性株系的183个单株)和T2代(来自6个T0代阳性株系的241个单株)转化植株进行白粉病抗性鉴定，Ta-Tlp基因超量表达的转基因植株，能延缓白粉病发病进程，其白粉病抗性有一定提高。对T2代阳性转化植株进行赤霉病抗性鉴定表明，其抗性与受体对照相比无显著差异。

Transformation of Wheat Thaumatin-Like Protein Gene and Diseases Resistance Analysis of the Transgenic Plants

The thaumatin-like protein in plants, an important member of pathogenesis-related proteins (PRs), involves in plant resistant reaction to many fungi. A series of thaumatin-like protein genes have been isolated and transformed to potato(Solanum tuberosum L.), rice (Oryza sativa L.), and wheat (Triticum aestivum L.) resulting in resistance improvement to plant diseases. We have cloned a thaumantin-like protein gene, Ta-Tlp, from wheat in our earlier studies. The Ta-Tlp gene expresses in high level in wheat 6VS/6AL translocation line with high resistance to powdery mildew (Erysiphe graminis f.sp. tritici Em. Marchal.), implying its close relation to the resistance of the disease. To further understand the gene’s function, we constructed Ta-Tlp into a expression vector driven by the strong ubi promoter in the present study. The constructed vector pAHC-TlP was transformed into immature embryo-derived calli of a common wheat cultivar Yangmai 158 through particle bombardment. After two rounds of herbicide bialaphos selection and regeneration, herbicide-resistance plants were obtained. The Ta-Tlp was confirmed having been integrated into the wheat genome and expressed in T1 and T2 generations by PCR, Southern blot, and RT-PCR. The transgenic plants of T0, T1, and T2 generations were inoculated by E. graminis f.sp. tritici and F. graminearum for resistance identification. All plants of T0, T1, (183 individuals derived from 6 positive T0 lines), and T2 (241 individuals derived from 6 positive T0 lines) generations appeared some resistance to wheat powdery mildew by delaying disease development, but no distinct resistance to scab (F. graminearum).