木霉植酸酶编码基因多样性及作为系统发育标记潜力研究

对现有的148株木霉菌株在含植酸钙的琼脂培养基上进行了产植酸酶能力鉴定,结果表明所有菌株均产生了水解透明图,说明所有测试的木霉菌株都具有植酸酶活性,植酸酶编码基因在木霉群体中具有广泛性.选取14个种类的21株木霉,采用植酸酶保守序列设计简并引物P8205、P500-2扩增获得其中11种17株木霉植酸酶基因片段,进行了序列测定；利用ITS4、ITS5引物扩增17个木霉菌株的ITS序列并测序.分别基于植酸酶基因片段序列以及ITS序列信息,通过邻接法(N-J法)构建系统发育树,结果表明植酸酶基因序列具有多样性的特点,而基于植酸酶基因序列与基于ITS序列的分类结果基本相同,不同的是长枝木霉(Trichoderma longibrachiatum)植酸酶基因序列与哈茨木霉(Trichoderma harzianum)被分到同一分支当中,与ITS序列的进化关系相差较大,表明有可以作为木霉分类的一种新的标记的潜力,并携带部分与ITS序列不同的系统发育相关信息.

Diversity and Potential Regarded as Phylogenetic Marks of Trichoderma Phytase Encoding Genes

Phytase hydrolytic experiments on agar medium containing calcium phytate were done with the existing 148 Triehoderma strains to carry out characterization of their phytase capability, the results showed that all of these strains generated hydrolytic halos around colonies, indicating all of the tested Trichoderma strains possessed phytase activity, and phytase encoding genes widely existed in Triehoderma population. 21 strains of 14 kinds of Trichoderma were chu- sen, and adopted conservative sequence of phytase to design degenerate primers P8205 and P500-2 and obtained phytase gene fragments of 11 kinds of 17 Trichoderma strains by amplification, and carried out sequencing; ITS4 and ITS5 primers were used to amplify ITS sequence of 17 Trichoderma strains and carry out sequencing. The phylogenetic trees were established through N-J method based on phytase gene fragments and ITS sequences information respective- ly. The results showed that phytase gene sequences had the characteristics of diversity, and the classificalion resulls based on both sequences were basically the same, the difference was that the phytase gene sequences of T. longibra- chiatum were placed into the same branch with T. harzianum, however, the evolution relation with ITS sequences differed fairly great, indicating that they had a potential as a new marker to classify Trichoderma, and carrying part of related phylogenetie information that differed from ITS sequences.