Ciclo de vida anfitálico de Agaricus subrufescens: análise genética e biológica

Abstract

Agaricus subrufescens is an edible mushroom with important medicinal properties. This species has amphithallic lifecycle producing homokaryotic and heterokaryotic spores in the same basidiomata. The heterocaryotic spores can result from the pairing of "sister" nuclei (= Nuclei Sister Pair Progeny - SNPP) or non "sister" nuclei (= Non Sister Nuclei Pair Progeny - NSNPP), resulting from the second division of meiosis. This study aimed to characterize genetically the three spores categories (homokaryons, SNPPs and NSNPPs), combined with a behavioral study of them. The classification was based on homo-heteroallelism through eight codominant molecular markers CAPS - Cleaved Amplified Polymorphic Sequence - under analysis of 225 offspring spores of a Brazilian strain WC837. The behavioral analysis was performed by (i) ability to cross tests between differents types of spores offspring (ii) analysis of mycelial growth rate and (iii) fruiting tests. Multilocus genotype test revealed that 50% spores were heterokaryotic and among them, 24% were considered to be SNPP. The homoallelism rate found by CAPS markers at centromere-unlinked was approximately 50% for SNPP and NSNPP. In fruiting tests, only NSNPP fruited. The mycelial growth rate between homokaryons and SNPP did not differ significantly. SNPP and NSNPP heterokaryons can cross with homokaryons. Crosses between SNPP and SNPP were also possible since both of them share different mating type alleles. From these data, it was possible to propose a simplified strategy to cross strains which have this type of amphithallism and select the NSNPPs spores through a single marker centromere-linked while SNPPs would be treated as homokaryons.