Production of Phytoalexins in Peanut (Arachis hypogaea) Seed Elicited by Selected Microorganisms

Under favorable conditions, the peanut plant demonstrates appreciable resistance to fungal invasion by producing and accumulating phytoalexins, antimicrobial stilbenoids. This mechanism for resistance is little understood, yet it is crucial for breeding and genetically modifying peanut plants to develop new cultivars with fungal resistance. The dynamics of phytoalexin production in peanut seeds and embryos challenged by selected important fungi and bacteria was investigated. Different biotic agents selectively elicited production of major peanut stilbenoids, resveratrol, arachidin-1, arachidin-3, and SB-1. Aspergillis species, compared to other biotic agents, were more potent elicitors of stilbenoids. Embryos demonstrated significantly higher production of stilbenoids compared to cotyledons and may serve as a convenient source of genetic material in isolating genes for peanut plant defense enhancement.