Genetic Variation in the Thermophilic Fungi of the Compost for the Button Mushroom, Agaricus bisporus

Abstract

Thermophilic fungi play an important role in determining selectivity of compost produced for growing Agaricus bisporus. Compost samples were collected during different stages of composting process from six mushroom growing states of India. Thermophilic microorganisms were isolated on yeast starch agar medium at 45 and 52ºC. Scytalidium thermophilum and Humicola insolense were predominant and frequently isolated in large numbers from compost prepared by long and short method on variety of substrates. In all, twenty four isolates of Scytalidium thermophilum and thirty one isolates of Humicola insolense were studied for their RAPD and ITS patterns. No intraspecific diversity in ITS lengths of 5.8S r-DNA gene could be observed in the isolates of both the thermophiles. Phylogenetic analyses of RAPD patterns determined seven and eight distinct groups of isolates in S. thermophilum and H. insolense, respectively.