Increased accumulation of phenolic metabolites in groundnut (Arachis hypogaea L.) genotypes contribute to defense against Sclerotium rolfsii infection

Abstract

Fungal infections cause several metabolic changes to the plants, which can affect its physiology and survival in various ways. In the present study, we have analysed various phenolic compounds and activity of oxidative enzymes in healthy and Sclerotium rolfsii-infected groundnut genotypes. Increased phenolics content and higher activity of oxidative enzymes was observed in the tolerant genotype (CS 19, GG 16) followed by susceptible genotype (GG 20, TG 37A). Among the phenolic compounds tested, chlorogenic acid content has increased greatly in leaf, stem and root of infected tolerant genotypes compared to the respective controls. In vitro growth of S. rolfsii showed significant inhibition at concentrations 500 and 1000 µg/mL of phenolic compounds in the radial growth inhibition assay. These results have strongly suggested that, higher accumulation of chlorogenic acid could be an important factor in imparting resistance and protecting groundnut against S. rolfsii infection in tolerant genotypes.

Keywords:

• Chlorogenic acid
• oxidative enzymes
• stem rot

Acknowledgement

We acknowledge ICAR – Directorate of Groundnut Research (D.G.R.), Junagadh, Gujarat, India for providing research funding and facilities. We are highly thankful to Dr. P.P. Thirumalaisamy, Sr. Scientist, Department of Pathology, D.G.R. for providing fungal culture of S. rolfsii and for his valuable suggestions. We are thankful to Dr. A.L. Singh, Department of Physiology, D.G.R. for providing ion chromatography facility.

Disclosure statement

The authors declared that they do not have any conflict of interest.