Research Of Straw Mushrooms Mating Type Factors

The Straw mushroom Volvariella volvacea is an important commercial mushroom and widely cultivated in Asia.However,the development of V.vovacea is limited by factors such as breeding of V.volvacea is limited due to an unclear sexual pattern.We decided to study monospore isolates from 5 wild strains and 2 cultivated strains of V.Volvacea to clarify the mating type system of V.volvacea.Primers used for cosegregation of the mip gene and A mating loci were based on the A mating locus sequence and the flanking,conserved mip gene of V.volvacea monospore strain PYd21.Amplicons were digested and two monospore isolates which displayed polymorphism were selected from each strain,resulting in a total of 14 monospore strains for further testing.The A mating loci of the 14 selected strains were amplified using long distance PCR,and sequenced with Sanger.Eight types of A mating loci sequences were obtained,including the sequence of PYdls and PYd21.Then comparatively analysis and predict the structure of eight obtained sequences.The results showed the sequences of the eight A mating loci were not conservative,so the primers that were designed according to known straw mushroom A mating loci can not be used to amplify the gene unknown A mating loci.By homology search,we found the B mating locus encodes 4 pheromone receptors with no pheromone gene in PYd21.Then the primers that were designed according to the sequence of 4 pheromone receptor gene of PYd21,were used to amplify B mating locus of 6 monospore strains with different A mating locus(except PYd15 and PYd21),sequenced,comparison analysis,the results showed that 4 pheromone receptor gene do not have polymorphism in different monospore strains,only individual SNP sites.So B mating locus in the mating process of straw mushroom,may not have the function.The previously selected 14 monospore isolates were crossed,and the 8 strains with different A mating type genes were reciprocally crossed,following the crossing,the hybrid strains were screened with the molecular method.The results showed the stains with different A mating locus,identical pheromone receptor gene can be crossed.