散斑壳属两近似种的表型性状和ITS序列分析比较研究

对针叶树散斑壳Lophodermium conigenum与其近似种南方散斑壳L.australe的形态学特征及生态习性等进行了比较研究,同时对这两个种8个菌株的rDNA-ITS区进行了PCR扩增和序列测定,结合GenBank中16个相关ITS序列构建了系统发育树。结果表明,L.conigenum与L.australe有着非常密切的关系。L.conigenum除子囊果形状、子座基部层、线纹和寄生性外,其余特征与L.australe基本相同。L.conigenum的ITS序列的G+C含量(51.0%)小于L.australe的G+C含量(54.0%)。在系统发育树中,此二种形成两个明显独立的分支,支持了依据形态学等表型性状的分类。二者种间及种内的遗传差异与寄主有较大的相关性,而与产地无明显关联。通过表型性状和ITS序列的分析与比较,可准确地将L.conigenum与L.australe鉴别开来。

Comparative study on phenotypic characteristics and ITS sequence analysis of Lophodermium conigenum and L. australe

Morphological characters and ecological habit, etc. of Lophodermium conigenum and related species L. australe were compared; besides, rDNA-ITS region of eight strains of the two species was amplified and sequenced, and phylogenetic trees were constructed based on these sequences as well as sixteen related ones in GenBank. Phenotypic characteristics of L. conigenum are remarkably similar to those of L. australe, except shape of ascomata, stroma basic layer, zone lines and parasitism. G+C content of L. conigenum (51.0%) is less than that of L. australe (54.0%). The phylogenetic analysis shows the two related species are sharply classified into two independent groups, which are consistent with the classification based on phenotypic characters. The interspecific and intraspecific genetic diversity is closely related to hosts, but not to distribution. The comparison analysis of phenotypic characteristics and ITS sequences could be used to distinguish L. conigenum and L. australe accurately.