Abstract

Gurvinder Kaur*1 and V. Padmaja2

Beauveria bassiana is a known natural enemy of a number of insect pests of crop plants. Molecular markers provide a means for constructing the molecular phylogeny, diversity and link to virulent phenotypes in order to screen different isolates of any given entomopathogens. Twenty-seven isolates of B. bassiana isolated from different insect hosts and from different geographical origins were characterized by PCR-based RAPD markers. DNA markers provide more detailed genomic information and are highly rewarding in view of stability and reliability of the parameter. Bioassays were conducted by using second instar larvae of Spodoptera litura in order to categorize the isolates based on virulence. The different isolates were arbitrarily rated as more virulent, moderately virulent and less virulent based on the speed of kill. Genetic relatedness between the different isolates based on RAPD analysis and pathogenicity was studied. Clustering pattern to a certain extent reflected the genetic resemblance between the isolates based on geographical distribution as the isolates, which were not isolated from India, did not show any pairing with other isolates. On the other hand, no correlation was found between the pathogenicity of the isolates and the relatedness of the original insect host.