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Genetic Safeguard against Mycotoxin Cyclopiazonic Acid Production in Aspergillus oryzae
Author(s) -
Kato Naoki,
Tokuoka Masafumi,
Shinohara Yasutomo,
Kawatani Makoto,
Uramoto Masakazu,
Seshime Yasuyo,
Fujii Isao,
Kitamoto Katsuhiko,
Takahashi Tadashi,
Takahashi Shunji,
Koyama Yasuji,
Osada Hiroyuki
Publication year - 2011
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.201000672
Subject(s) - cyclopiazonic acid , aspergillus oryzae , aspergillus flavus , mycotoxin , gene cluster , biology , aflatoxin , metabolite , gene , biochemistry , aspergillus , genetics , fermentation , microbiology and biotechnology , intracellular
Aspergillus oryzae is a fungus widely used in traditional Japanese fermentation industries. Its inability to produce mycotoxins, due to mutation or transcriptional repression of the genes responsible for their biosynthesis, is consistent with the hypothesis that A . oryzae is a domesticated species derived from A . flavus , a wild species that is a well‐known producer of aflatoxin. In contrast, the cyclopiazonic acid (CPA) biosynthetic gene ( cpa ) cluster in A . oryzae contains genes that have been lost in A . flavus . Through targeted gene inactivation, isolation of the corresponding metabolite, and evaluation of biological activity of the metabolite, we demonstrated that an A . oryzae ‐specific gene— cpaH —mediates the conversion of CPA into the less toxic 2‐oxocyclopiazonic acid, a new analogue of CPA. The detoxifying properties of cpaH , which have been lost in the A . flavus pathway, reflect the relationship of the two species.