부산대학교 도서관

Aspergillus flavusis a common filamentous fungus that produces aflatoxins and presents a major threat to agriculture and human health. Previous phylogenetic studies of A. flavushave shown that it consists of two subgroups, called groups I and II, and morphological studies indicated that it consists of two morphological groups based on sclerotium size, called “S” and “L.” The industrially important non-aflatoxin-producing fungus A. oryzaeis nested within group I. Three different gene regions, including part of a gene involved in aflatoxin biosynthesis (omt12), were sequenced in 33 S and L strains of A. flavuscollected from various regions around the world, along with three isolates of A. oryzaeand two isolates of A. parasiticusthat were used as outgroups. The production of B and G aflatoxins and cyclopiazonic acid was analyzed in the A. flavusisolates, and each isolate was identified as “S” or “L” based on sclerotium size. Phylogenetic analysis of all three genes confirmed the inference that group I and group II represent a deep divergence within A. flavus.Most group I strains produced B aflatoxins to some degree, and none produced G aflatoxins. Four of six group II strains produced both B and G aflatoxins. All group II isolates were of the “S” sclerotium phenotype, whereas group I strains consisted of both “S” and “L” isolates. Based on the omt12 gene region, phylogenetic structure in sclerotium phenotype and aflatoxin production was evident within group I. Some non-aflatoxin-producing isolates of group I had an omt12 allele that was identical to that found in isolates of A. oryzae.