Identification of extracellular differential proteins of Aspergillus flavus wild type and LaeA deficient strains

ObjectiveThe present study was conducted to analyze extracellular differential proteins of Aspergillus flavus wild type and LaeA deficient strains cultured in wheat and corn substrates, in order to provide data for further understanding the roles of regulatory factor LaeA in regulation of aflatoxin production. MethodThe wheat and corn grains were grinded, sterilized and made into culture substrate by adding proper amount of water. Samples were taken at 0, 48 and 72 h after being inoculated with toxigenic strains(A. flavus CA14 wild type) and avirulent strains(LaeA deficient type) in substrates. SDS-PAGE was applied to analyze aflatoxin B1(AFB1) and extracellular differential proteins, and LC-MS-MS(Q-TOF) technology was employed to identify the extracellular differential proteins. ResultA. flavus wild type and LaeA deficient strains could degrade small molecular proteins in wheat and corn substrates quickly. As time extended, LaeA deficient strains contained fewer extracellular differential proteins than wild type strains and produced no aflatoxin. There were seven extracellular differential protein bands in toxigenic strains and avirulent strains, which were mainly biological enzymes such as alpha-amylase A, alkaline protease, 1,4-beta-xylanase F3 and leucine aminopeptidase A.ConclusionThe extracellular differential proteins in A. flavus toxigenic strains and avirulent strains belong to biological enzymes. These enzymes are related to nutrition intake and affect the growth of A. flavus mycelia.