Comparative Analysis of Peroxidase and Catalase Isoenzymes via Native-PAGE Electrophoresis and SDS-PAGE Profiling of Leaf Proteins in Rice Varieties under Infection Stress

Rice (Oryza sativa L.) is a staple food for over half of the world's population. However, rice productivity is significantly hindered by various diseases, including sheath blight caused by Rhizoctonia solani. This study aims to evaluate the resistance of different rice varieties and wild rice accessions to sheath blight and to analyze the biochemical responses, specifically peroxidase and catalase activities, under infection stress. The results revealed that Kalanamak and Pusa Basmati were highly susceptible, with high disease indices and visual ratings. Conversely, wild rice accessions such as O. rufipogon and O. australiensis exhibited lower disease indices, indicating moderate resistance. Peroxidase activity varied significantly among the rice leaves, ranging from 148.83 to 182.44 mg/g fresh weight/min. Dhanya 748 showed the highest peroxidase activity, followed by O. australiensis and O. rufipogon. Native-PAGE electrophoresis of peroxidase isoenzymes demonstrated high-intensity bands in O. rufipogon, BPT 5204, and Swarna Sub-1, while minimal or no bands were observed in other genotypes, indicating varying levels of peroxidase activity. Catalase activity also showed significant variation, ranging from 138.18 to 152.14 mg/g fresh weight/min. BPT-5204 exhibited the highest catalase activity, followed by O. australiensis and Pusa Basmati. Isoenzyme analysis via Native-PAGE revealed high-intensity catalase bands in O. australiensis, Dhanya 748, NDR 118, and Pusa Basmati, while no bands were observed in O. rufipogon, CSR 13, Arize 6444, and Swarna Sub-1. SDS-PAGE analysis of leaf proteins showed variability in banding patterns. Non-infected leaves of Swarna Sub-1, Arize 6444, Kalanamak, and Pusa Basmati had minimal bands, while O. australiensis and Dhanya 748 showed maximum bands. Infected leaves of CSR 13, NDR 118, Arize 6444, Kalanamak, Dhanya 748, and Pusa Basmati had minimal bands, whereas O. australiensis exhibited maximum bands. Overall, the study highlights the potential of wild rice species in enhancing disease resistance and provides insights into the biochemical responses of rice varieties under pathogen stress.