Genetic Variability and Antagonistic Potential of Trichoderma harzianum Isolates Against Sclerotium rolfsii

摘要

Eleven isolates of Trichoderma harzianum were obtained from three different tobacco growing regions of West Godavari district in Andhra Pradesh. Genetic variability and antagonistic potential in these isolates against Sclerotium rolfsii infecting tobacco were assessed. All isolates of T. harzianum inhibited mycelial growth of S. rolfsii in dual culture by production of both volatile and non-volatile compounds. They also produced HCN and indole acetic acid. Positive activity was observed for 8 of 9 isozymes tested in native PAGE for all isolates of T.harzianum. Esterase, peroxidase, superoxide dismutase, malate dehydrogenase, catalase, alcohol dehydrogenase, acid phosphotase showed polymorphic banding pattern whereas polyphenol oxidase gave a monomorphic pattern. Malate dehydrogenase showed intense activity in terms of a maximum number of banding loci. Identical protein profiles were observed for all isolates except GP-1 in SDS-PAGE. The isolates were grouped into three main clusters by UPGMA. The genetic similarity coefficients varied between 0.22 and 0.61 among the isolates. There was no correlation between the isozyme pattern and antagonistic property of these isolates against the pathogen.