Genetical evidence supporting the multicellular origin of fruiting body formation in the basidiomycete, Lentinula edodes

By using mitochondrial DNA (deoxyribonucleic acid; mtDNA) restriction fragment length polymorphisms as genetic markers, mtDNA composition of fruiting bodies formed on the mating colonies between two compatible monokaryons with different mtDNA genotypes was examined to expand our understanding of the cellular origin of fruiting bodies in the basidiomycete Lentinula edodes (Berk.) Pegler, Shiitake. Fruiting bodies formed at peripheral points of both parent sides of mated colonies were found to exclusively retain the mtDNA genotypes of the nuclear recipient monokaryons. However, fruiting bodies formed at the junction zone of paired monokaryons, where two types of dikaryons with the same nuclei but different mtDNAs occur, carried two different mtDNA genotypes of both parents. This association of two different mtDNAs in a single fruiting body indicates that it can be constructed by two types of dikaryons which differ in mtDNA, suggesting that the origin of the fruiting bodies of L. edodes is not a single cell, but multicellular.