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本文以来自国内外的20株白菜黑斑病菌及近源种为研究材料,进行了5.8SrDNA及其侧翼ITS区的克隆、测序、序列变异及遗传进化关系分析。黑斑病菌及其近源种真菌核糖体5.8SrDNA及其侧翼ITS区序列比对结果显示,不同种菌株ITS1比ITS2在碱基构成上有更大变异,而且ITS1的序列长度变异比ITS2的大;而种内虽然各菌株的寄主和地理来源不同,但ITS1和ITS2在长度上均没有变异,碱基构成上存在微小的变异。对该区序列的聚类分析表明,白菜黑斑病菌3个种芸薹链格孢Alternariabrassicae、甘蓝链格孢A.brassicicola和萝卜链格孢A.japonica虽然地理来源和寄主不同,但种内的不同菌株均在一个独立的聚类组中,种之间以及其和链格孢属内其它种在聚类关系上能明显分开,可基于该区进行黑斑病菌的分类鉴定。
In this paper, 20 cabbage black spot pathogens and their near-origin sources from home and abroad were selected as research materials. The cloning, sequencing, sequence variation and genetic evolution of 5.8S rDNA and its ITS region were analyzed. The comparison of 5.8SrDNA and ITS ITS sequences of the black spot pathogen and its near-origin fungus ribosome showed that ITS1 had more variation in base composition than ITS2 in different strains, and ITS1 sequence length variation was larger than ITS2 Although the hosts and geographical origin of each strain varied, ITS1 and ITS2 showed no variation in length and slight variations in base composition. Cluster analysis showed that there were three species of Alternaria brassicae Alternaria albicans, A. brassicicola and A.japonica from Alternaria brassicae, although their geographical origin and host were different, Different strains are in an independent cluster group, and the species and the other species within the genus Alternaria can be significantly separated in the cluster relationship, based on the region for the identification of Alternaria.