Induction of resistance in Arachis hypogaea L. against Peanut mottle virus by nitric oxide and salicylic acid

Peanut mottle virus (PeMV) causing mottling, yellowing, necrosis, malformation and stunting was isolated from naturally infected peanut plants grown in El-Sharkiya Governorate. The virus was isolated mechanically and identified by indirect ELISA using both specific and induced polyclonal antiserum. Effect of virus infection on cell organelles, detected by electron microscopy, showed different degrees of degenerative changes in chloroplasts, mitochondria, nucleus, revealed amorphous and cylindrical cytoplasmic inclusions in infected leaf cells as pinwheel and laminated bundles. Pinwheel inclusion bodies are characteristic of Potyviruses which include PeMV. Two field experiments were conducted in 2006 and 2007 to study the effect of spraying sodium nitroprusside (SNP) and salicylic acid (SA) at 50, 100, and 200 μmol/l to induce resistance against PeMV infection in peanut plants (cv. Giza 5). All treatments induced resistance against PeMV infection, when plants were sprayed before inoculation with the virus. Also, all tested treatments gave a significant increase in photosynthetic pigments and activity of peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT), superoxide dismutase (SOD) and phenylalanine ammonia lyase (PAL) compared with infected plants. Moreover, all treatments recorded increments in seed protein and oil contents at harvest time. Also, the total unsaturated and saturated fatty acids content increased in the treated peanut seeds compared with the untreated ones.

Effect of treatment with SNP and SA on resistance enzymes specific activity (units min−1 mg−1 protein). Means values ± SE (n = 3).Figure optionsDownload as PowerPoint slideHighlights
► In this study PeMV was isolated from infected plants and identified by ELISA.
► 2 Experiments were studied the effect of SNP and SA against PeMV infection.
► All treatments induced resistance, when plants sprayed by virus before inoculation.
► Also, all treatments gave increase in pigments and enzymes activity.
► Moreover, TUS and TS fatty acids content increased in treated peanut seeds.