Molecular characterization of the relationships among Amylomyces rouxii, Rhizopus oryzae, and Rhizopus delemar

Abstract

Twenty-one strains of Amylomyces rouxii isolated from starters of Asian fermented foods were divided into two groups, lactic acid (LA) and fumaric and malic acid (FMA) producers, by organic acid productivity in liquid culture. Phylogenetic analysis based on the ldhB gene, ribosomal RNA encoding DNA (rDNA) internal transcribed spacer (ITS) sequence, and genome-wide amplified fragment length polymorphism (AFLP) revealed that A. rouxii was grouped into two major clusters as to organic acid accumulation, corresponding to Rhizopus oryzae and Rhizopus delemar. These observations suggest that the species A. rouxii is composed of two distinct types, derived from R. oryzae or R. delemar via domestication in the starters.