Genetic diversity of Armillaria spp. symbiotic with Polyporus umbellatus in China

The growth and development of Polyporus umbellatus sclerotia is dependt on a symbiotic relationship with Armillaria, a species of forest pathogenic fungus. Our aim was to identify the Armillaria spp. that are symbiotic with Polyporus umbellatus in China. Samples of Armillaria spp. were isolated from Polyporus umbellatus from 31 districts among 13 provinces in China. Armillaria spp. were identified using DNA-based methods targeting the IGS region of ribosomal DNA. Genotypes were differentiated by the Inter-simple sequence repeat (ISSR) analysis. The results showed that Armillaria gallica and Armillaria cepistipes were the species most frequently observed to be symbiotic with P. umbellatus in China. Two dendrograms were generated based on the similarity matrix by the Unweighted Pair Group Method with Arithmetic Mean (UPGMA), wherein the genotypes of A. gallica were grouped into four clusters and the genotypes of A. cepistipes were grouped into three clusters. This study showed that there is genetic diversity among the genotypes of A. cepistipes and A. gallica that are symbiotic with P. umbellatus.