Arbuscular mycorrhizal fungi (AMF) influence silicon (Si) uptake by plants, but the mechanisms remain unclear. This study investigated the mechanisms of AMF-mediated Si uptake by rice, a model Si-accumulating plant, and explored the tripartite interactions among AMF, Si, and phosphorus (P). AMF inoculation increased shoot Si content by 97% when supplied with silicic acid and by 29% with calcium silicate and upregulated expression of Si transporters Lsi1 and Lsi2 in roots. Supplying Si only to AMF hyphae increased the root Si content by 113%, indicating direct Si uptake by hyphae. Mechanisms of AMF-induced Si uptake were elucidated: 1) direct Si uptake by hyphae, 2) increased silicate dissolution, and 3) upregulation of Si transporters. Silicon application also increased AMF colonization by 28%, and the absence of interactions was observed on P uptake. Altogether, AMF support Si acquisition and Si fosters AMF colonization in rice, whereas the P uptake depends more on AMF than on Si.

中文翻译：

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丛枝菌根真菌增加水稻硅吸收的机制


丛枝菌根真菌（AMF）影响植物对硅（Si）的吸收，但其机制仍不清楚。本研究研究了水稻（一种典型的积硅植物）AMF介导的硅吸收机制，并探讨了AMF、硅和磷（P）之间的三方相互作用。当提供硅酸时，AMF 接种使地上部硅含量增加了 97%，当提供硅酸钙时，地上部硅含量增加了 29%，并且根中硅转运蛋白 Lsi1 和 Lsi2 的表达上调。仅向 AMF 菌丝供应 Si 可使根部 Si 含量增加 113%，表明菌丝直接吸收 Si。阐明了 AMF 诱导的硅吸收机制：1）菌丝直接吸收硅，2）增加硅酸盐溶解，3）硅转运蛋白的上调。硅的施用还使 AMF 定植增加了 28%，并且在磷吸收方面没有观察到相互作用。总而言之，AMF 支持 Si 的获取，Si 促进 AMF 在水稻中定植，而 P 的吸收更多地依赖于 AMF 而不是 Si。