番茄中一个抗病基因功能的研究

摘要

The proteins encoded by the biggest type of disease-resistant genes(R) in plants contain coiled-coil(CC) and nucleotide-binding site(NBS) and leucine-rich repeat(LRR) domain structure.R genes are famous for its disease resistance.In this paper, DDI3 gene was screened out by means of yeast two-hybrid, which had interaction with functional DDB1 gene and contained the CC-NBS-LRR structure.It was predicted to have disease resistance of R gene and involved in plant disease resistance.The DDI3 overexpression vector was constructed and transferred into the wild type tomato plants through agrobacterium-mediated transformation, and the positive transgenic plants with high expression of DDI3 were obtained.By the pathogen inoculation experiment, the apparent plant disease and statistical number of bacterial colonies were observed.It is found that the resistance of transgenic plants is obviously higher than that of wild type tomato.DDI3 gene functioning as a resistance is a very good method to improve the disease resistance of tomato, which is a new attempt in the improvement of the disease resistance of tomato by using gene engineering technology.DDI3 also interacts with tomato DDB1 gene, providing a new direction to the research on the function of DDB1 in plant disease resistance.%植物中最大的一类抗病基因(R)编码的蛋白质含有卷曲螺旋结构(coiled-coil,CC) 、核苷酸结合位点(nucleotide-binding site,NBS)和富含亮氨基酸的重复序列(leucine-rich repeat,LRR)结构域.R基因以抗病著称.文章通过酵母双杂筛选方式获得了DDI3基因,该基因与番茄中重要功能基因DDB1具有相互作用,而又含有CC-NBS-LRR结构,预测具有R基因抗病性,参与植物抗病.研究中构建了DDI3过表达载体并通过根瘤农杆菌介导转化到野生型番茄中,筛选获得DDI3高表达的阳性转基因株系.通过病菌接种实验,观察植株发病情况和统计细菌菌落数,结果发现,转基因植株的抗病性明显高于野生型番茄.DDI3基因对提高番茄的抗病性有很高的价值,为采用基因工程方法改良番茄植株抗病性做出新的尝试,同时又与番茄DDB1基因具有相互作用,对研究DDB1基因在参与植物抗病途径中的功能研究提供新的方向.