An assessment of genetic variation in Stereum hirsutum (Basidiomycota) based on RAPD markers

Abstract

Randomly amplified polymorphic DNA (RAPD) marking with five decamer primers (OPA-01, OPA-04, P36, P46, P49) was applied to 41 samples, which were fruitbody tissue isolates of corticioid wood decay fungus S. hirsutum from 18 collection sites in Belarus, situated 0.18–278 km apart. Each primer produced a unique fingerprint for each individual genotype. The samples belong to 35 different genotypes; the identity of RAPD profiles was observed for the samples collected from the same substratum unit. Among 65 reproducible RAPD loci selected for the analysis, there were no strictly monomorphic ones; a single marker had very high frequency (0.94); 29% of markers had the frequencies more than 0.5; the average marker frequency was 0.36. Cluster analysis showed no groups correlated with host, substratum type, or geographical origin, except 3 genotypes from the same collection site, forming a separate cluster. A collection site with the biggest subsample (26% of all studied genotypes) possessed 85% of bands and 100% of them were polymorphic inside this subsample. Average Dice similarity coefficient was almost identical between the genotypes within collection sites (less 0.15 km apart; SD =0.53) and for the widely separated individuals (more 40 km; SDD=0.52). The molecular data infer highly outcrossing reproduction mode in the studied regional sampling of S. hirsutum and the absence of any genetic differentiation.