Biochemical Defense Responses in Red Rice Genotypes Possessing Differential Resistance to Brown Planthopper, Nilaparvata lugens (Stål)

SIMPLE SUMMARY: Rice, an imperative food crop, suffers from infestation by various insect pests. They cause considerable losses to rice production and quality. Among insect pests, the brown planthopper (Nilaparvata lugens Stål.) is a severe problem in the rice growing regions of the Indian sub-continent. Host-plant resistance is the safest way of managing this pest. We conducted a study to understand the differences in biochemical and defense enzyme activities in red rice genotypes, which showed different degrees of resistance to N. lugens. We experimented with net house condition. All the test genotypes were challenge infested with N. lugens. Cuttack population (Biotype 4). Changes in biochemical factors because of N. lugens feeding were assessed at 0, 24, 48, and 72 h. The results revealed significant differences in the quantity of total phenol and soluble protein, along with the activities of the defense enzymes such as peroxidase, polyphenol oxidase, catalase, and super-oxide dismutase among tested genotypes. The action of these defense-related enzymes was significantly higher in highly resistant genotypes, followed by resistant and moderately resistant genotypes. The crude silica content of all the genotypes showed a similar trend. In this experiment, we reported six highly resistant genotypes, namely Mata Meher, Manipuri Black, Hermonona, Sonahanan, Bavdi and Bacharya Khuta. The study might lead to the utilization of these lines in an N. lugens resistance breeding program. ABSTRACT: The brown planthopper [Nilaparvata lugens (Stål.)] is one of the most destructive insect pests in all the rice-growing regions of the world. The pest is complicated to manage through the blanket application of chemical pesticides. The development of stable, durable N. lugens-resistant rice varieties is the most economical and efficient strategy to manage the pest. Landraces of red rice genotypes possess numerous nutritional and stress-resistant properties, though an exclusive study on the same is yet to be carried out. In the present study, we evaluated 28 red rice genotypes, along with two resistance checks and one susceptibility check, for their resistance to N. lugens. These promising lines revealed differential responses in the defense mechanism against the pest. The resistant accessions showed a greater accumulation of phenols, peroxidase, polyphenol oxidase, catalase, and superoxide dismutase under N. lugens-stressed conditions. However, the concentration of soluble proteins was substantially decreased in all the test genotypes. The concentration of crude silica was at maximum in highly resistant genotypes. Six red rice genotypes, namely Mata Meher, Manipuri Black, Hermonona, Sonahanan, Bavdi, and Bacharya Khuta fall under the highly resistant category, and can be utilized as valuable sources of resistance in breeding programs.