Discrimination between edible and poisonous mushrooms among Japanese Entoloma sarcopum and related species based on phylogenetic analysis and insertion/deletion patterns of nucleotide sequences of the cytochrome oxidase 1 gene

Abstract

Entoloma sarcopum is widely known as an edible mushroom but appears morphologically similar to the poisonous mushrooms E. rhodopolium sensu lato (s. l.) and E. sinuatum s. l. Many cases of food poisoning caused by eating these poisonous mushrooms occur each year in Japan. Therefore, they were recently reclassified based on both morphological and molecular characteristics as sensu stricto species. In this study, we analyzed the nucleotide sequences of the rRNA gene (rDNA) cluster region, mainly including the internal transcribed spacer regions and mitochondrial cytochrome oxidase 1 (CO1) gene, in E. sarcopum and its related species, to evaluate performances of these genes as genetic markers for identification and molecular phylogenetic analysis. We found that the CO1 gene contained lineage-specific insertion/deletion sequences, and our CO1 tree yielded phylogenetic information that was not supported by analysis of the rDNA cluster region sequence. Our results suggested that the CO1 gene is a better genetic marker than the rDNA cluster region, which is the most widely used marker for fungal identification and classification, for discrimination between edible and poisonous mushrooms among Japanese E. sarcopum and related species. Our study thus reports a new genetic marker that is useful for detection of Japanese poisonous mushrooms, Entoloma.