Trichoderma harzianum及其近缘种的分子系统学研究

Molecular phylogenetic analysis of Trichoderma harzianum and its related species

Trichodermaharzianum是木霉属内最常见的一个“集合种”。本研究对来源不同的T .harzianum及其相似种的 4 6个菌株进行了ITS序列测定 ,将其ITS1 5 .8S ITS2序列与来自EMBL的参考菌株的序列进行比较 ,并进行系统发育分析 ,此外对其中的 18个菌株进行了RAPD多态性分析 ,试图明确T .harzianum的多样性以及与其相似种之间的关系。ITS结果表明 ,T .harzianum及其相似种可分成 2个群 (A、B) :A群由T .hamatum、T .asperellum、T .atroviride、T .koningii和T .viride组成 ,并形成 2个分支 ,表明T .viride和T .koningii、T .atro viride的亲缘关系较近 ,而与T .hamatum、T .asperellum较远 ;B群由T .spirale、T .hamatum、T .inhamatum、T .harzianum和T .anam .Hypocreavinosa组成 ,并形成 6个分支。T .inhamatum可分成 2个群 (Ti1、Ti2 )、T .harzianum至少可分成 5个群 (Th1、Th2、Th4、Th5、Th6 )。结果还表明T .hamatum的遗传差异较大 ,T .hama tum的模式菌株归属于A群 ,而其他的T .hamatum的菌株归属于B群。

Trichoderma harzianum is one of the most common aggregate species of the genus. Based on different molecular characterizations, strains of T. harzianum have been divided into different subgroups, which has created confusion. We reexamined reference strains representing different subgroups under the name T. harzianum and its related species. Phylogenetic analysis using the NEIGHBOR program in the PHYLIP package based on ITS1 5.8S rDNA ITS2 sequence data distributed the tested strains among two phylogenetic groups (A and B), which was supported by high bootstrap values. Group A contains T. hamatum , T.asperellum, T. atroviride, T.koningii and T.viride , and is divided into two clades. T.viride is more closely related to T.koningii and T.atroviride than to T. hamatum and T. asperellum . Group B contains T. spirale , T. hamatum , T. inhamatum , T. harzianum and T. anam. Hypocrea vinosa , and is divided into six clades. T. inhamatum is further divided into two subgroups (Ti1 and Ti2), and T. harzianum comprises at least five subgroups(Th1, Th2, Th4, Th5 and Th6). The phylogenetic analysis of ITS1 5.8S rDNA ITS2 sequence also indicated the heterogeneity of T. hamatum ,since a neotype of T. hamatum is located in group A but other strains of T. hamatum are located in group B. The RAPD analysis of 18 strains representing T. harzianum and its related species coincided with phylogeny based on sequence analysis of the ITS regions.