Cool season grasses associate asymptomatically with foliar Epichloë endophytic fungi in a symbiosis where Epichloë spp. protects the plant from a number of biotic and abiotic stresses. Furthermore, many grass species can accumulate large quantities of silicon (Si), which also alleviates a similar range of stresses. While Epichloë endophytes may improve uptake of minerals and nutrients, their impact on Si is largely unknown. Likewise, the effect of Si availability on Epichloë colonization remains untested. To assess the bidirectional relationship, we grew tall fescue (Festuca arundinacea) and perennial ryegrass (Lolium perenne) hydroponically with or without Si. Grasses were associated with five different Epichloë endophyte strains [tall fescue: AR584 or wild type (WT); perennial ryegrass: AR37, AR1, or WT] or as Epichloë-free controls. Reciprocally beneficial effects were observed for tall fescue associations. Specifically, Epichloë presence increased Si concentration in the foliage of tall fescue by at least 31%, regardless of endophyte strain. In perennial ryegrass, an increase in foliar Si was observed only for plants associated with the AR37. Epichloë promotion of Si was (i) independent of responses in plant growth, and (ii) positively correlated with endophyte colonization, which lends support to an endophyte effect independent of their impacts on root growth. Moreover, Epichloë colonization in tall fescue increased by more than 60% in the presence of silicon; however, this was not observed in perennial ryegrass. The reciprocal benefits of Epichloë-endophytes and foliar Si accumulation reported here, especially for tall fescue, might further increase grass tolerance to stress.

冷季草与叶面无症状关联埃皮克洛埃内生真菌共生，其中埃皮克洛埃种。保护植物免受多种生物和非生物胁迫。此外，许多草种可以积累大量的硅（Si），这也可以减轻类似的压力。尽管埃皮克洛埃内生菌可能会改善矿物质和营养物质的吸收，但它们对硅的影响很大程度上未知。同样，Si 可用性对埃皮克洛埃殖民化尚未经过考验。为了评估双向关系，我们种植了高羊茅（羊茅）和多年生黑麦草（多年生黑麦草）水培法，有或没有Si。草与五种不同的埃皮克洛埃内生菌菌株[高羊茅：AR584或野生型（WT）；多年生黑麦草：AR37、AR1 或 WT] 或作为埃皮克洛埃-自由控制。高羊茅关联观察到了相互有益的影响。具体来说，埃皮克洛埃无论内生菌菌株如何，高羊茅叶子中硅的浓度至少增加了 31%。在多年生黑麦草中，仅在与 AR37 相关的植物中观察到叶硅含量增加。埃皮克洛埃Si 的提升是（我）独立于植物生长的反应，并且（二）与内生菌定植呈正相关，这为内生菌效应提供了支持，而与内生菌对根生长的影响无关。 而且，埃皮克洛埃当硅存在时，高羊茅中的定殖增加了 60% 以上；然而，在多年生黑麦草中没有观察到这一点。的互惠互利埃皮克洛埃-此处报道的内生菌和叶面硅积累，尤其是高羊茅，可能会进一步提高草对胁迫的耐受性。