Journal of Pure and Applied MicrobiologyVol. 6 No. 4

RAPD Marker Assisted Development of Improved Strains of Agaricus bisporus (Lange) Sing

Shivani Chauhan1, Shammi Kapoor2 and Saneel K. Thakur3

1Department of Pharmacology and Toxicology, College of Veterinary and Animal Sciences, CSKHPKV, Palampur - 176 062, India. 2Department of Microbiology, Punjab Agricultural University, Ludhiana, Punjab - 141 004, India. 3Department of Chemistry, Sri Sai University, Palampur - 176 062, India.

Received on 18 October 2012 and accepted on 30 November 2012

 

ABSTRACT

Agaricus bisporus, commonly known as the button mushroom, is the most widely cultivated species of edible fungi. Many polymorphic molecular markers have been exploited for strain identification in wild and commercial strains of this mushroom. The aim of this study was to develop hybrid strains using random amplified polymorphic DNA (RAPD) markers. For this purpose A. bisporus germplasm consisting of nineteen Agaricus bisporus parental strains (P-1, U-3, S-11, CM-1 to CM-16) were screened for yield, quality and morphological parameters. Out of these, ten parental strains were selected (P-1, U-3, S-11, CM-5, CM-7, CM-8, CM-10, CM-13, CM-14 and CM-16) which were found to be better than others. They were further analyzed for degree of divergence among them through RAPD analysis. They were found to possess similarity coefficient ranging between 0.73 to 0.98. These ten strains were used for spore collection. From spores germinated on Lambertís medium more than 500 single spore isolates (SSIís) were isolated. These SSIís were put to fruiting test out of which only 22 SSIís did not show fruiting and were selected for intra-crossing for development of hybrid. Out of 17 crosses made only 5 showed compatibility between monokaryons i.e. resulted in hybrid development. Five A. bisporus parental strains , their ten single spore isolates (SSIs) and five hybrid strains so obtained were further assessed for their similarity using 10 single 10bp primers, producing 252 scorable and 81 polymorphic bands. UPGMA clustering analysis showed three major phylogenetic clusters. First and second cluster comprised of 8 strains showing intra-cluster variation, third cluster had four genetically distinguishable strains. Germplasm strains mostly had strandy/dense colonies on Potato Dextrose Agar and the strains differ significantly in mycelium growth rate. However, these environmentally variable morphological traits could not be utilized as sole criteria for establishing strainal identities. Hence, the RAPD profile generated in this study along with morpho-physiological description could be used as a reference for identification of A. bisporus strains.

Keywords : Agaricus bisporus, Genetic diversity, RAPD analysis, Molecular marker.