Molecular Characterization of Brown Planthopper Resistant Gene in Rice (Oryza Sativa L.)

Abstract

Rice (Oryza sativa L.) is a primary staple food crop for billions of people worldwide. India has the biggest area under rice cultivation, as it is one of the principal food crops. However, production of this crop is greatly hampered by several biotic and abiotic factors. Among the biotic factors Brown Plant Hopper (BPH), Nilaparvata lugens (Stal.) (Homoptera: Delphacidae) is considered as one of the most important insect pest in rice. The aim of this study was to evaluate the 17 rice genotypes at morphological, physiological, biochemical and at molecular level under BPH stress along with expression analysis of three gene viz. PR6, PR9 and AOS gene. In the present study it was observed that BPH stress cause significant morphological, physiological, biochemical and molecular changes in rice. Various morphological parameters like plant height, flag leaf area, spikelet fertility, spikelet per panicle and 1000-grain weight are significantly decreased after BPH stress. Physiological and biochemical parameters like chlorophyll content, phenolic compounds both are decreased due to BPH infestation. The studied rice germplasm were characterized at molecular level using 14 SSR markers. The Jaccard coefficient values for all the 17 rice genotype ranged from 0.25 to 0.87. The minimum similarity recorded by genotype Kasturi and PTB-33, whereas the maximum similarity was shown between Vallabh Basmati-24 and Vallabh Basmati-22. The result shows very high expression values of genes viz. PR6, PR9 and AOS, after BPH infestation in four rice varieties i.e Pitambi-33, Kasturi, Pusa Basmati-1 and REMRE-1, as compare to control. Identified resistant rice varieties can be used as donor line for further breeding program. Chemical control measures were used earlier as effective means to control BPH which are not eco-friendly and pose toxicity to certain extent. The donor rice varieties identified in the study will serve as source of BPH resistant genes and provide more eco-friendly approach to control BPH.