关键词: 分子鉴定, 多基因标识, 绿僵菌, 系统发育, 亲缘性

Abstract: The classical identification of Metarhizium spp. is based on the morphological characteristics, which usually results in complex groups within a species. DNA molecular identification can offer a more refined and accurate classification of the species in Metarhizium genus, which is very important for studies on breeding, insecticide mechanism and ecology of the fungus. Here, four potential biocontrol strains of Metarhizium IPPM010202, IPPM2029, IMI330189 and M200614 were identified by phylogenetic analysis of five identified genes, i.e., ribosomal transcribed spacer sequences (ITS1-4), beta-tubulin, RNA polymerase Ⅱ first, second subunit (RPB1 and RPB2), and translation extension factor (EF-1α). Based on the phylogenetic tree constructed from the four candidate strains and twenty-two reference strains, the four strains were located on three branches of the phylogenetic tree. The strain IPPM010202 and IPPM2029 belong to M. pingshaense, IMI330189 is identified as M. acridum and M200614, as M. frigidum, a species adaptive to low temperature. They have close genetic relationship between each other, with genetic distance of 0.021-0.036. Also, the results showed that the ITS1-4 sequence had higher mutation frequency and mutation range, which makes it a superior classification gene. The EF-1α sequence had the advantage in identifying the strain and analyzing genetic relationship. The multigene phylogeny can compensate for the limitations of single gene analysis, so that it can obtain a more accurate identification and more detailed classification.

Key words: molecular identification, polygene marker, Metarhizium anisopliae, phylogeny, cluster analysis