P-260 - Effect of Seed Coat Integrity and Alternative Disinfection on Aflatoxin Gene Expression in Aspergillus flavus-infected Peanut Seeds

Evaluation of alternative seed disinfection methods is essential to maintain peanut seed coat integrity and reduce aflatoxin contamination risks. The seed coat in peanut (Arachis hypogaea) serves as a physical and chemical barrier, rich in phenolic and flavonoid compounds that inhibit Aspergillus flavus colonization and aflatoxin synthesis. Conventional disinfectants, such as chlorine-based solutions or ethanol, may compromise these protective compounds. This study assessed alternative seed disinfection treatments, specifically 2% citric acid and 2% sodium chloride (NaCl), compared to a conventional chlorine-based method (1% sodium hypochlorite). Peanut seeds from resistant (BC127, BC138, BC154, BC120, BC21) and susceptible (BC1, BC164, BC50, BC115) breeding lines were surface-sterilized by immersion (10 min), rinsed, inoculated with Aspergillus flavus AF36 spores (5 × 10^5 spores per microliter), and incubated under controlled conditions (28°C, 85% relative humidity, 12 days). RNA was extracted, and relative quantitative PCR (qPCR) assessed expression of aflatoxin biosynthesis genes aflE and aflR. Seeds disinfected with citric acid and NaCl exhibited significantly lower aflE and aflR expression levels compared to chlorine-treated seeds. These results indicate that alternative disinfection methods effectively maintain seed coat integrity and chemical defenses, reducing aflatoxin biosynthesis potential.