Studies On Species And Genetic Diversity Of Metarhizium Strains Isolated From The Soil Collected From Anhui

Metarhizium isolates from soil have received considerable attention as aimportant potential biological control agent of pest insects. To reveal the geneticrelationship, genetic structure and mechanism of genetic differentiation ofMetarhizium anisopliae var. anisopliae isolated from Anhui soil, the genetic diversityand genetic differentiation of104individuals in7Metarhizium anisopliae var.anisopliae populations were studied by ISSR method. Meanwhile,13selectedMetarhizium strains based on morphological study were amplified and sequenced forits internal transcribed spacer (ITS) sequence. To illustrate the species diversity ofMetarhizium isolated from Anhui soil, the ITS phylogenetic tree with the relatedstrains obtained by homology search on GenBank web site by using Blast method wasconstructed by neighbor-joining method. The results are as follows:1Genetic diversity of7Metarhizium anisopliae var. anisopliae populations wasinvestigated by the Inter-Simple Sequence Repeat (ISSR) technique using8specificand stable primers selected from60primers. A total of79sites were generated,79ofwhich (100%) were polymorphic.2The data were analyzed by POPGENE32. The average percentage ofpolymorphic loci of populations was100%and demonstrated abundant geneticdiversity (the average value of Shannon index (I) was0.4425). To some extent, bothgene flow and genetic diversity were present among populations (Nm was4.4282,average Nei’s index was0.2796, and average Gst was0.1015). The gene proportionof diversity reached89.85%within population but was10.15%among populations.This demonstrated that genetic variation of Metarhizium anisopliae var. anisopliaepopulations was mainly within populations.3UPGMA cluster analysis showed that the genetic similarities among7Metarhizium anisopliae var. anisopliae populations were not related withgeographical sources.4The internal transcribed spacer (ITS) sequences of l3Metarhizium strainsisolated from Anhui soil was amplified and sequenced. We searched for homologyusing the BLAST programs available at the web site of the National Center forBiotechnology Information, and the phylogenetic tree for the genus Metarhizium wasconstructed by Neighbor-Joining method. The results showed that the tested strainswere located in3clades of the phylogenetic tree.8Metarhizium strains and theMetarhizium anisopliae var. anisopliae type were classified into clade I，1strain and the M. anisopliae var. lepidiotum type were grouped into clade III，and4strains andthe M. flavoviride var. pemphigum type were classified into clade X. Combined withthe homologous comparative data, the eight strains, the one strain and the four strainsare identified as Metarhizium anisopliae var. anisopliae, M. anisopliae var. lepidiotumand M. flavoviride var. pemphigum, respectively. The phylogenetic analysis of ITSsequence could provide the important reference for identification of the genusMetarhizium.