Comparison of Aflatoxin Production in Normal- and High-Oleic Backcross-Derived Peanut Lines

Abstract

The effect of the high-oleate trait of peanut on aflatoxin production was tested by comparing normal oleic lines with high-oleic backcross-derived lines. Seeds were blanched, quartered, and inoculated with Aspergillus flavus conidia, placed on moistened filter paper in petri dishes, and incubated for 8 days. In one experiment, dishes were stacked in plastic bags in a Latin square design with bags and positions in stacks as blocking variables. High-oleic lines averaged nearly twice as much aflatoxin as normal lines. Background genotype had no significant effect on aflatoxin content, and interaction between background genotype and oleate level was not detected. In a second experiment, dishes were arranged on plastic trays enclosed in plastic bags and stacked with PVC spacers between trays. Fungal growth and aflatoxin production were greater than in the first experiment. Background genotype, oleate level, and their interaction were significant. The mean of high-oleic lines was almost twice that of normal lines, but the magnitude of the difference varied with background genotype. Special care should be taken with high-oleic lines to prevent growth of Aspergillus spp. and concomitant development of aflatoxin contamination.

Identification of a Novel Mutation in FAD2B from a Peanut EMS Mutant with Elevated Oleate Content

“…It is well recognized that the 3 conserved histidine boxes of FAD2 are vital to its activity and that any mutations in these regions may lead to reduction or loss of activity and specifi city 12,13,15 . 6 , so in peanut, cultivar releases with 72 oleate were found to encounter germination/emergence problems at low temperature 25 , and high oleate peanut lines also exhibited increased ability to support aflatoxin production during storage 26 . Maintaining a good balance between oleate and linoleate in peanut is therefore considered judicious 6 , but how much oleate linoleate is most appropriate in peanut is still unknown.…”

Inactivation of the Lipoxygenase ZmLOX3 Increases Susceptibility of Maize to Aspergillus spp.

“…β-oxidation mutants of A. nidulans were defective in ST production in oleic acid-amended culture medium as well as on maize seed (Maggio-Hall et al 2005). Furthermore, field studies have shown that peanut seeds with high oleic acid content are more heavily contaminated with AF (Xue et al 2003). Thus, it is possible that the increased oleic acid content of the infected lox3–4 kernels contributed to the higher ST/AF production by the fungi.…”

Fatty acid unsaturation, mobilization, and regulation in the response of plants to stress

“…Interestingly, when the levels of aflatoxin production were measured in normal-and high-18:1 backcross-derived peanuts, the high-18:1 peanuts averaged nearly twice as much aflatoxin as normal lines. The increase in 18:1 associated with the high 18:1 trait of peanut was achieved by a corresponding reduction in the level of 18:2, the fatty acid reported to support aflatoxin production in fungal culture (Xue et al 2003).…”