Visual Estimation of Aflatoxin Production in Peanut with Aspergillus Norsolorinic Acid Mutants1

Abstract Peanut seed and pods are susceptible to contamination by aflatoxin (AF), a carcinogenic mycotoxin produced by Aspergillus flavus Links Fr. and A. parasiticus Speare. Efforts to evaluate peanut lines for resistance to AF contamination have been impeded by limitations to the methodologies available for AF detection. AF cannot be seen by visible light and its detection involves grinding seed tissue in organic solvents, separation of phases, and detection by ELISA, high performance liquid chromatography (HPLC) or thin layer chromatography. These methodologies are time-consuming, expensive, labor-intensive, and are uninformative in defining the tissues of the peanut seed and pod that are most frequently contaminated with AF. Aspergillus AF mutants which accumulate norsolorinic acid (NOR), an orange-pigmented AF pathway intermediate, provide an easy and convenient mean to detect AF contamination. A visual rating scheme for NOR contamination of peanut seed was developed that correlated favorably to HPLC...