Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/15/2015
Publication Date: 1/9/2016
Citation: Hua, S.T., Chang, P., Beck, J.J., Li, R.W. 2016. Regulation of aflatoxin biosynthesis and branched-chain amino acids metabolism in Aspergillus flavus by 2-phenylethanol reveal biocontrol mechanism of Pichia anomala. Meeting Abstract. https://pag.confex.com/pag/xxiv/meetingapp.cgi/Paper/21990.
Technical Abstract: Pichia anomala WRL-076 is a biocontrol yeast which has been shown to inhibit growth and aflatoxin production of A. flavus. Using the SPME-GC/MS analysis we identified that the volatile, 2-phenylethanol (2-PE) produced by this yeast and demonstrated that the compound inhibited aflatoxin production. We further characterized the temporal transcriptome response of A. flavus to 2-PE at a subinhibitory level (1µl/ml). A total of 131 of the 13,485 A. flavus genes were significantly impacted during the 72h experimental period at False Discovery Rate <0.05. Eighty-two of these genes exhibited decreased expression including those that encode conidiation proteins. All genes in the aflatoxin gene cluster were significantly decreased during the first 48 h treatment. Gene Ontology (GO) analyses showed that GO terms related to metabolism of propionate and branched-chain amino acids were significantly enriched in the down-regulated gene group, while those associated with ribosome biogenesis, translation, and biosynthesis of a-amino acids were over-represented among the up-regulated genes. Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that metabolic pathways negatively impacted among the down-regulated genes were those involved in valine, leucine and isoleucine degradation, propanoate metabolism, and tryptophan metabolism. These degradation and metabolic pathways most likely are required for aflatoxin biosynthesis by providing building blocks and energy. A better understanding of the mode of action of 2-PE at low concentrations, a scenario likely to be encountered in field applications of the biocontrol yeast, is critical to the development of an effective biocontrol strategy.