Quantitative Proteomic Analysis for High- and Low-Aflatoxin-Yield Aspergillus flavus Strains Isolated From Natural Environments

Abstract

The molecular mechanisms underlying aflatoxin production have been well-studied in strains of the fungus Aspergillus flavus (A. flavus) under artificial conditions. However, aflatoxin biosynthesis has rarely been studied in A. flavus strains isolated from field conditions with different aflatoxin-producing ability. In the present study, tandem mass tag (TMT) labeling and high-performance liquid chromatography (HPLC) coupled with tandem-mass spectrometry analysis were used for proteomic quantification in natural isolates of high- and low-aflatoxin-yield A. flavus strains. Additionally, findings obtained using the TMT-labeling method were validated using the high-resolution multiple reaction monitoring (MRM-HR) method. In total, 4,363 proteins were quantified, among which 1,045 proteins were differentially expressed between the high- and low-aflatoxin-yield A. flavus strains. Bioinformatics analysis showed that the up-regulated proteins were significantly enriched in carbon-related metabolism and the biosynthesis of secondary metabolites, whereas the down-regulated proteins were enriched in oxidative phosphorylation. Moreover, GST proteins were found to be significantly down-regulated in high-yield A. flavus strains; this result contradicted previous findings obtained from A. flavus strains grown under artificial conditions. In summary, our study provides novel insights into aflatoxin regulation in A. flavus under field conditions and could facilitate the development of various strategies for the effective control of aflatoxin contamination in food crops.

Lysine Succinylation of VBS Contributes to Sclerotia Development and Aflatoxin Biosynthesis in Aspergillus flavus

“…Thus, we perform a TMT-labeled quantitative lysine succinylome to comprehensively report the changes in Ksuc levels between high and low AF production strains of A. flavus isolated under natural conditions. From our quantitative global proteomics data, we noticed that the upregulated proteins in the high AF yield group were mostly enriched in carbon-related metabolism, whereas the downregulated proteins were enriched in oxidative phosphorylation; through subsequent functional analysis, we found that the upregulated proteins involved in carbon-related metabolism had a direct relationship with AF production ( 48 ).…”

“…In this study, all protein samples were obtained from our previous global proteomics protein preparation and prepared from a single experiment ( 48 ). In detail, 10 6 conidia was inoculated into liquid YES media and shaken at 180 revolutions/min for 5 days at 28 °C.…”

Impact of Lysine Succinylation on the Biology of Fungi

“…Employing tandem mass tag (TMT)-labeled quantitative lysine succinylome, they extensively documented the variations in Ksuc levels between A. flavus strains exhibiting high and low aflatoxin production under natural conditions. Subsequent functional analysis revealed a direct correlation between the upregulated proteins involved in carbon-related metabolism and aflatoxin production [147].…”

Current Insights in Fungal Importance—A Comprehensive Review

“…The last stage of AFB1 production is the conversion of sterigamtocystin into aflatoxin B2. The conversion of sterigamatocystin into O–methylsterigmatocystin (OMST) is catalyzed by an O-methyltransferase encoded by the aflP ( omtA ) gene, whose expression is highly influenced by the growth conditions [ 310 , 311 ]. The A-ring of O–methylsterigmatocystin (OMST) is oxidized, and an intermediate named 11-hydroxy-O-methylsterigmatocystin (HOMST) is formed.…”