Induction of defence enzymes activities in rice plant treated by seaweed algae against Rhizoctonia solani Kuhn causing sheath blight of rice

Abstract

Rice Sheath Blight is caused by Rhizoctonia solani which becomes a major problem. The use of natural products such as seaweed provides a rich source of structurally diverse and biologically active secondary metabolites, and is the ultimate way of combating these diseases. In this context, seaweed algae such as Dictyota dichotoma, Chondrococcus hornemannii, Jania rubens and Caulerpa scalpelliformis were used to control rice sheath blight. Enzymatic studies were carried out on peroxidase, polyphenol oxidase, phenylalanine ammonia lyase and β-1,3- glucanase. The rice plants were treated with Dictyota dichotoma along with soil application of Bacillus subtilis, the four enzymes raised the glucose concentration to 60.34 µg, 3.73 µg, 5.21 µg and 232 µg respectively, and then the plants were treated with the chemical called Hexaconazole and the four enzymes raised 59.20 µg, 3.57 µg, 5.17 µg and 229.3 µg respectively. While comparing these enzymes, β-1,3- glucanase release glucose content in large amount both in seaweed treated plant and also in chemical treated plant. This present study was undertaken to evaluate the various extracts of seaweeds algae such as brown, red and green seaweed along with the enzyme studied, would increase the resistance of grapes to sheath blight of rice.