Determination of genetic variability among the isolates of Metarhizium anisopliae var. anisopliae from different geographical origins

The entomopathogenic fungus Metarhizium anisopliae is currently used as an efficient biological control agent against different insects. The prevalence and genetic variability of the entomopathogenic fungus Metarhizium anisopliae var. anisopliae in Asian countries (China, Laos, Singapore and South Korea) and a European country (The Netherlands) was examined. The fungus was found to be widespread in agricultural and forest soils throughout China especially in the south and south western regions, with a maximum recovery percentage of 81.6, while in Laos it was found to be abundant in the forest soils only, the soil of Netherlands also seemed to be an excellent source of entomopathogens with a significant recovery of insect pathogenic fungi. Simple sequence repeats (SSR) and ITS-rDNA sequence data showed that the isolates are closely linked to each other. The gene diversity (He) and polymorphic information content values of sixty two isolates showed mean values of 0.37 and 0.63. The majority of the isolates belonged to one of the closely related genotypes and these were found to be dominant in the agricultural as well as forest ecosystem. Genetic distances among the isolates according to locations and different sources showed minimal variation ranging from 0.23 to 0.34%, with maximum genetic distance of 0.34% among the isolates from Laos and The Netherlands. The reason for the limited variation is uncertain, however even the similarity index among the isolates can endow with sufficient knowledge for the implications of the methods to develop this fungus as a microbial control agent.