Microorganisms and culture conditions
The microorganisms used in this work were B. trispora ATCC 14271, mating type (+) and B. trispora ATCC 14272, mating type (). Both strains were obtained from the American Type Culture Collection (ATCC) (Rockville, MD, USA). The strains were grown on potato dextrose agar (PDA) Petri dishes at 26 C for 4 days for sporulation. Eight ml of sterile distilled water was added to the Petri dish and the spores were collected by scraping off the medium surface. The spore suspension containing 1.5 106 and
4.0 105 spores/ml of the strains 14271 and 14272, respectively, was used to inoculate the medium.