PDF(Pubmed)
Abstract：
Silicon (Si) uptake is generally beneficial for plants that need protection from insect herbivores. In pursue of mechanisms involved in Si-mediated defense, we comprehensively explored the impact of Si on several defensive and metabolic traits in rice exposed to simulated and real herbivory of Mythimna loreyi Duponchel larvae. Hydroponic experiments showed that Si-deprived rice supplemented with Si 72 h prior to insect infestation were similarly resistant to larvae as plants continuously grown in Si-containing media. Both Si and herbivory altered primary metabolism in rice, including the levels of several sugars, amino acids, and organic acids. While the accumulation of sugars was generally positively correlated with Si presence, multiple amino acids showed a negative correlation trend with Si supplementation. The levels of secondary metabolites, including isopentylamine, p-coumaroylputrescine and feruloylputrescine, were typically higher in the leaves of Si-supplemented plants exposed to herbivory stress compared to Si-deprived plants. In addition, simulated herbivory treatment in Si-supplemented plants induced more volatile emissions relative to Si-deprived plants, which was consistent with the increased transcripts of key genes involved in volatile biosynthesis. In ecological interactions, Si alone did not affect the oviposition choice of M. loreyi but gravid females showed a significant preference for simulated herbivory-treated/Si-deprived compared to Si-supplemented plants. Our data suggest that apart from mechanical defense, Si may affect rice metabolism in multiple ways that might enhance/modulate defense responses of rice under herbivory stress.
摘要：
硅(Si)吸收通常对于需要保护免受昆虫食草动物侵害的植物是有益的。在追求硅介导的防御机制中，我们全面探索了Si对暴露于模拟和真实食草动物MythimnaloreyiDuponchel幼虫的水稻中几种防御和代谢性状的影响。水培实验表明，当植物在含硅培养基中连续生长时，在昆虫侵染前72小时补充Si的无硅水稻对幼虫的抗性相似。Si和食草动物都改变了水稻的初级代谢，包括几种糖的含量，氨基酸,有机酸。虽然糖的积累通常与Si的存在呈正相关，多种氨基酸与Si的补充呈负相关趋势。次级代谢物的水平，包括异戊胺,对香豆酰腐胺和阿魏酸酰腐胺，与失去Si的植物相比，暴露于食草胁迫的Si补充植物的叶子通常更高。此外,在补充Si的植物中模拟食草处理相对于剥夺Si的植物诱导更多的挥发性排放，这与参与挥发性生物合成的关键基因的转录本增加一致。在生态互动中，单独使用Si并不影响M.loreyi的产卵选择，但与补充Si的植物相比，妊娠雌性对模拟食草动物处理/Si剥夺表现出显着偏好。我们的数据表明，除了机械防御，Si可能以多种方式影响水稻代谢，可能增强/调节水稻在草食性胁迫下的防御反应。
