Distribution of A factor and the colony phenotype in single spore isolates of Volvariella volvacea
草菇子代单孢菌株的菌落类型与A因子分布规律研究

In order to verify the genetic character of Volvariella volvacea, 124 single spore isolates of the strain V23 were selected. Colony morphology on the flat plate was observed. Two kinds of colony phenotype were roughly divided: aerial type (44 isolates) and creeping type (80 isolates). PCR amplification and molecular markers associated with mating factors were used for testing and verifing the distribution of A1 and A2 factors. Among all the dicaryotic strains, the number of homokaryon was 101 and heterokaryon 23, with the proportion of 81.45% and 18.55%, respectively. The number of isolates with A1 factor was 20 amounting to 45.45% of the aerial type isolates. The number of isolates with A2 factor was 15 amounting to 34.09% of the aerial type isolates. The number of creeping type isolates with A1 factor was 15 amounting to 18.75% of creeping type isolates. A2 factor was predominant in creeping type isolates and there were 51, sharing 63.75%. There is no connection between A factor and colony phenotype. Through crossing between isolates of different phenotype with different A factor and then screening by PCR, we obtained true 20 hybrids. The proportion of aerial type to creeping type is 1:1. As long as the aerial type took part in the hybridization, the majority of the colony phenotype in the hybrids was aerial. Hybridization between isolates of creeping type resulted in that the majority of the phenotype in the hybrids was creeping. Fruiting experiment of 8 hybrids selected showed that, only one could fruit.