Silicon (Si) enhances rice resistance to various insect herbivores. However, the underlying mechanisms remain unclear. Whereas the salicylic acid (SA) signaling pathway plays a vital role in plant defense responses to sucking insects, its role in Si-enhanced rice resistance has not been investigated. Si transporter mutant OsLsi1 and mutants with antisense expression of ICS (as-ics) and NPR1 (as-npr1) in the SA pathway and their corresponding wild types (WT) were treated with and without Si to determine Si effects on rice resistance to brown planthopper (BPH), Nilaparvata lugens (Stål), as well as on SA accumulation, defense-related enzyme activity and gene expression. Si application significantly affected host preference of BPH, significantly reduced honeydew secretion and inhibited oviposition and hatch rate. Upon BPH infestation, SA content, transcript levels of BPH3, ICS1 and PAL4, and activities of POD, SOD, PPO and PAL were significantly higher in Si-treated than untreated plants. The defense responses were also faster. However, OsLsi1 mutant plants displayed higher susceptibility to BPH and minimal defense responses. Furthermore, simultaneous application of SA and Si in WT plants showed the highest resistance to BPH, but had no obvious effect on OsLsi1, antisense as-ics and as-npr1 plants. Our results suggest that Si enhances rice defense against the sucking insect BPH by defense priming and the Si-mediated priming involves SA signaling pathway.

硅 (Si) 增强了水稻对各种昆虫食草动物的抵抗力。然而，潜在的机制仍不清楚。尽管水杨酸 (SA) 信号通路在植物对吸食昆虫的防御反应中发挥着至关重要的作用，但其在 Si 增强水稻抗性中的作用尚未得到研究。Si 转运蛋白突变体OsLsi1和在 SA 途径中具有反义表达 ICS ( as-ics ) 和 NPR1 ( as-npr1 ) 的突变体及其相应的野生型 (WT) 用和不用 Si 处理以确定 Si 对水稻抗褐变的影响飞虱 (BPH)、褐飞虱(Stål)，以及 SA 积累、防御相关酶活性和基因表达。Si应用显着影响BPH的宿主偏好，显着减少蜜露分泌并抑制产卵和孵化率。在 BPH 侵染后，Si 处理的植物中SA 含量、BPH3、ICS1和PAL4 的转录水平以及 POD、SOD、PPO 和 PAL 的活性显着高于未处理的植物。防御反应也更快。然而，OsLsi1突变植物表现出对 BPH 更高的易感性和最小的防御反应。此外，在野生型植物中同时施用SA和Si对BPH的抗性最高，但对反义OsLsi1无明显影响。as-ics和as-npr1植物。我们的研究结果表明，Si 通过防御启动增强了水稻对吸吮昆虫 BPH 的防御，并且 Si 介导的启动涉及 SA 信号通路。