Abstract:

【Objective】 The influences of silicon (Si) on rice growth and the activity of pathogenesis-related proteins were investigated to link roles of Si with Xoo resistance in rice. 【Method】 An Xoo-susceptible rice variety (Oryza sativa L. cv. Nipponbare) was grown hydroponically to study the effect of different Si application methods on dry weight of plants with or without inoculation, and the effect of Si addition or not on key enzyme activities and the resistance to Xoo after inoculation. 【Result】 The results showed that shoot and root dry weight were significantly decreased by inoculation of Xoo strain. The total dry weight and Si content in rice were increased significantly after silicon addition. The severity index of the infected plants treated with silicon was decreased by 11.83%-52.12% compared to the control, and the relative immunization efficiency reached 16.55%-75.82%. The activities of β-1,3-glucanase, exochitinase and endochitinase were all quickly increased after inoculation with Xoo strain. The β-1,3-glucanase activity in rice plants supplied with silicon was significantly higher than that in plants deprived of silicon during the eight days after inoculation, and reached the maximum on the eighth day after inoculation with Xoo strain. The exochitinase and endochitinase activities of leaves in silicon-fed plants evidently increased throughout the experimental period. 【Conclusion】 Silicon application could facilitate the rice growth, enhance the enzyme activity of β-1,3-glucanase, endochitinase and exochitinase, reduce severity index, significantly alleviate the damage of Xoo to rice and attain controlling efficacy.

Key words: Si, rice, Xoo, pathogenesis-related proteins, resistance