Gene expression analysis to predict aflatoxins B1 and G1 contamination in some plant origin foods

Maize, peanuts and wheat are exposed to colonisation by Aspergillus flavus and Aspergillus parasiticus, which are mould species able to produce aflatoxins B-1 (AFB(1)) and G(1) (AFG(1)). New tools based on molecular data can be used to obtain critical information to prevent AFs accumulation in these crops. The objective of this study was to analyse the time course of the relative expression of the aflR, aflS and aflP genes by reverse transcription real-time PCR (RT-qPCR) in relation to AFs production by A. flavus and A. parasiticus on maize, peanuts and wheat under controlled conditions during nine days of incubation. Different gene expression profiles for the three target genes were observed in maize, peanut and wheat. In general, AFB(1) amounts produced by both species were increased over incubation time, although A. parasiticus produced higher AFB(1) quantities than A. flavus in peanuts and wheat. Regarding AFG(1) production, quantities were higher at the end of the incubation time but lower than AFB(1) amounts. High relationships were found between gene expression by day 4 and AFs production by days 7 and 9. Thus, gene expression data allow predicting early AFs contamination of maize and wheat. In the case of peanuts further studies are needed.