Yan Wang1, Wei Lin1, Hao Yan2, Jing Neng1, Yong Zheng1, Kai Yang1, Fuguo Xing3, Peilong Sun1. 1. College of Food Science and Technology, Zhejiang University of Technology/Key Laboratory of Food Macromolecular Resources Processing Technology Research (Zhejiang University of Technology), China National Light Industry, Hangzhou, China. 2. Zhejiang Provincial Centre for Disease Control and Prevention, Hangzhou, China. 3. Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Beijing, China.
Abstract
BACKGROUND: Aspergillus ochraceus causes food spoilage and produces mycotoxin ochratoxin A (OTA) during storage of agricultural commodities. In this study, citral was used to inhibit A. ochraceus growth and OTA accumulation, proteomic analysis was employed to verify the mechanism of citral. RESULTS: Citral was found to significantly inhibit fungal growth and mycotoxin production in A. ochraceus. Specifically, 75, 125, 150 and 200 μL L-1 citral suppressed mycelial growth by 33%, 46%, 50% and 100%, respectively. Additionally, 75 μL L-1 citral inhibited OTA accumulation by 25%. Proteomic analysis was performed to elucidate the inhibitory mechanism of citral on mycelial growth and OTA production at subinhibitory concentrations (75 μL L-1 ). Proteomics analysis identified 2646 proteins in A. ochraceus fc-1, of which 218 were differentially expressed between control and 75 μL L-1 citral treatment samples. Differentially expressed proteins were identified by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of biological process, cellular component and molecular function terms. Potential factors affecting mycelial growth and OTA production were analysed, and OTA production was revealed to be a complex process involving many associated factors related to various processes including nutrient intake, sterol biosynthesis, ribosome biogenesis, energy metabolism, oxidative stress and amino acid metabolism. In addition, citral at 75 μL L-1 down-regulated OTA biosynthetic genes including pks and nrps, but slightly up-regulated the global regulatory factors veA, velB and laeA. CONCLUSION: The findings further demonstrate the potential of citral for the preservation of grains and other agricultural products, and provide new insight into its antifungal mechanisms at subinhibitory concentrations.
BACKGROUND:Aspergillus ochraceus causes food spoilage and produces mycotoxin ochratoxin A (OTA) during storage of agricultural commodities. In this study, citral was used to inhibit A. ochraceus growth and OTA accumulation, proteomic analysis was employed to verify the mechanism of citral. RESULTS:Citral was found to significantly inhibit fungal growth and mycotoxin production in A. ochraceus. Specifically, 75, 125, 150 and 200 μL L-1 citral suppressed mycelial growth by 33%, 46%, 50% and 100%, respectively. Additionally, 75 μL L-1 citral inhibited OTA accumulation by 25%. Proteomic analysis was performed to elucidate the inhibitory mechanism of citral on mycelial growth and OTA production at subinhibitory concentrations (75 μL L-1 ). Proteomics analysis identified 2646 proteins in A. ochraceus fc-1, of which 218 were differentially expressed between control and 75 μL L-1 citral treatment samples. Differentially expressed proteins were identified by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of biological process, cellular component and molecular function terms. Potential factors affecting mycelial growth and OTA production were analysed, and OTA production was revealed to be a complex process involving many associated factors related to various processes including nutrient intake, sterol biosynthesis, ribosome biogenesis, energy metabolism, oxidative stress and amino acid metabolism. In addition, citral at 75 μL L-1 down-regulated OTA biosynthetic genes including pks and nrps, but slightly up-regulated the global regulatory factors veA, velB and laeA. CONCLUSION: The findings further demonstrate the potential of citral for the preservation of grains and other agricultural products, and provide new insight into its antifungal mechanisms at subinhibitory concentrations.