Isolation and genotype analyses of ascospores produced between genetically different Arthroderma benhamiae strains.

Abstract

Thirty-one single ascospore cultures were obtained from one ascoma produced in mating of RV 26678 (+) (Institut de Medicine Tropicale, Antwerp, Belgium) and KMU 4169 (-) (Dept. Dermatology, Kanazawa Medical University, Uchinada, Japan), which are genetically different strains of Arthroderma benhamiae. The isolation was performed with the aid of an inverted microscope and a binocular microscope. The internal transcribed spacer (ITS) regions of the nuclear ribosomal RNA gene of all the ascospore cultures were analyzed by restriction fragment length polymorphism (RFLP) with the restriction enzyme HinfI. The mating types of all the single-ascospore cultures were also checked. Eight cultures had mating type (+) and RV 26678 genotype, 10 had mating type (-) and RV 26678 genotype, 6 had mating type (+) and KMU 4169 genotype and 7 had mating type (-) and KMU 4169 genotype. There was no linkage between the mating types and the genotypes, implying that the genes control the mating behavior and the genes of ribosomal RNA are on different chromosomes from each other. The hybrids comprised half of the isolates and so they were actually from the ascospores and not from the microconidia or the peridial hyphae.