Aspergillus Colonization and Aflatoxin Contamination in Peanut Genotypes with Reduced Linoleic Acid Composition

Abstract

Aspergillus flavus and A. parasiticus can contaminate several agricultural crops with the toxic fungal metabolite aflatoxin. Previous research has indicated that resistance may be conferred by altering the fatty acid composition of these crops. Recently, peanut breeding lines with reduced linoleic acid content have been developed. The purpose of this study was to examine the effect of reduced linoleic acid composition on preharvest aflatoxin contamination of peanut. Seven breeding lines with relatively low linoleic acid and two check genotypes were grown in a randomized complete block design with 10 replicates for 4 years in Georgia and for 3 years in Arizona. The plots were inoculated with a mixture of A. flavus and A. parasiticus about 60 days after planting and subjected to drought and heat stress for the 40 days immediately preceding harvest. Differences were observed in only one environment. Low linoleic acid composition had no measurable effect on preharvest aflatoxin contamination in peanut when data were combined across years and locations. Products of the lipoxygenase pathway that have been shown to affect aflatoxin biosynthesis in vitro may not be present in sufficient quantities in peanut.