title: Autoxidated linolenic acid inhibits aflatoxin biosynthesis in Aspergillus flavus via oxylipin species.
abstract: Aflatoxins produced by Aspergillus species are among the most toxic and carcinogenic compounds in nature. Although it has been known for a long time that seeds with high oil content are more susceptible to aflatoxin contamination, the role of fatty acids in aflatoxin biosynthesis remains controversial. Here we demonstrate in A. flavus that both the saturated stearic acid (C18:0) and the polyunsaturated linolenic acid (C18:3) promoted aflatoxin production, while C18:3, but not C18:0, inhibited aflatoxin biosynthesis after exposure to air for several hours. Further experiments showed that autoxidated C18:3 promoted mycelial growth, sporulation, and kojic acid production, but inhibited the expression of genes in the AF biosynthetic gene cluster. Mass spectrometry analyses of autoxidated C18:3 fractions that were able to inhibit aflatoxin biosynthesis led to the identification of multiple oxylipin species. These results may help to clarify the role of fatty acids in aflatoxin biosynthesis, and may explain why controversial results have been obtained for fatty acids in the past.
authors.affiliation: Agro-biological Gene Research Center, Guangdong Academy of Agricultural Sciences, Tianhe District, Guangzhou 510640, China; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Haidian District, Beijing 100093, China.
authors.forename: Shijuan
authors.initials: S
authors.lastname: Yan
authors.affiliation: Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Haidian District, Beijing 100093, China.
authors.forename: Yating
authors.initials: Y
authors.lastname: Liang
authors.affiliation: Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Haidian District, Beijing 100093, China.
authors.forename: Jindan
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Agro-biological Gene Research Center, Guangdong Academy of Agricultural Sciences, Tianhe District, Guangzhou 510640, China.
authors.forename: Zhuang
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Haidian District, Beijing 100093, China. Electronic address: cmliu@ibcas.ac.cn.
authors.forename: Chun-Ming
authors.initials: CM
authors.lastname: Liu
mesh_terms: D000348:Aflatoxins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D001231:Aspergillus flavus / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*; D053898:Biosynthetic Pathways / Q000187:drug effects*; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D054883:Oxylipins / Q000378:metabolism*; D011753:Pyrones / Q000378:metabolism; D013172:Spores, Fungal / Q000187:drug effects / Q000254:growth & development; D013229:Stearic Acids / Q000378:metabolism; D017962:alpha-Linolenic Acid / Q000378:metabolism*
chemical_list: D000348:Aflatoxins; D054883:Oxylipins; D011753:Pyrones; D013229:Stearic Acids; D017962:alpha-Linolenic Acid; C031183:stearic acid; C011890:kojic acid
keywords: Aflatoxin production; Aspergillus flavus; Autoxidation; Inhibition; Linolenic acid; Oxylipins