Biochemical Basis of Resistance to Yellow Vein Mosaic Virus in Okra

An investigation was undertaken to know the biochemical basis of resistance to okra yellow vein mosaic virus (OYVMV) in susceptible cultivated okra (A. esculentus), resistant related wild species and their interspecific hybrids. The results revealed that wild parents resistant to OYVMV had maximum phenolics, peroxidase, polyphenol oxidase activity and seed soluble protein content while cultivated okra had minimum of these whereas inter-specific hybrids recorded in between their parents. However, sugars (reducing, non reducing and total) and total nitrogen content were found minimum in resistant wild parents, maximum in cultivated okra and intermediate in case of inter-specific hybrids. In OYVMV resistant plants infected with OYVMV, phenolic content decreased while peroxidase and polyphenol oxidase activity, total nitrogen and sugar content increased when compared with OYVMV resistant healthy plants while an exact opposite trend was observed in the OYVMV susceptible healthy and infected plants. Higher amount of phenols and their oxidation products like quinines formed by increased peroxidase and poly phenol oxidase may be responsible for reduced virus multiplication which finally could have lead to resistant reaction in wild okra and their interspecific hybrids.