Trypsin (serine protease) inhibitors in peanut genotypes aiming for control of stored grain pests

Abstract

Peanut seeds from different genotypes were evaluated for activities of trypsin inhibitors (serine protease), based on in vitro and in vivo assays, aiming to further selection of genitors in breeding programs for tolerance of stored grain pests. The in vitro assays were based on inhibition of insect digestive enzymes and also on thermal and pH stabilities of seed protein, while the in vivo assays were performed with insects Alphitobius diaperinus, Tribolium castaneum, Tenebrio molitor and Spodoptera frugiperda. Seed inhibitors of all genotypes inhibited bovine trypsin at 70 to 94%. The seed extract of BRS Havana inhibited T. castaneum and T. molitor up to 80% while the extract of BRS 151 L7 inhibited A. diapennus at nearly 20%. The seed inhibitors of both cultivars were stable at 80°C and also at different pH values. The two peanut genotypes are recommended as promising parents for breeding program aiming to selecting lines with tolerance to Tenebrio and Alphitobius insects.