Silicon Mediated Defense Response in Rice Plants Against Brown Plant Hopper Nilaparvata lugens (Stål)

Abstract

As silicon is known to have a positive role in enhancing the resistance of rice plants to insects, an investigation on one aspect of the biochemical and molecular basis of rice plant defences mediated by silicon amendments against brown plant hopper Nilaparvata lugens (Stål), comprising eld, pot culture and laboratory experiments was undertaken in OUAT. Two organic products; Diatomaceous Earth (DAE) at 0.15, 0.30 and 0.45 t/ha, and Rice Hull Ash (RHA) at 2, 3, 4 t/ha, along with one inorganic source, calcium silicate (CaSiO 3 ) at 2, 3, 4 t/ha were soil applied as basal to evaluate their effects on the accumulation of silicon, proline, phenol, carbohydrates and protein in the plant tissues along with proteomic and Scanning Electron Microscope (SEM) studies. Results showed decreasing in proline and protein contents and increasing in silicon, phenol and carbohydrates contents in infected Si amended plants as compared to the control. Proteomic study showed appearing of a thick band of about 20 KDa in infested plants indicating its role in defense mechanism. Under SEM, the dumbbell shaped deposits of Si were marked clearly at different doses of silicon, indicating that the increase in silica dose enhanced its deposits, which was supported by EDAX-SEM data. Results of this study clearly demonstrated that soil amendments with silicon through organic and inorganic sources effectively caused biochemical and molecular changes that ultimately support the plant defenses against BPH.