The endophytic fungus Falciphora oryzae was initially isolated from wild rice (Oryza granulata) and colonizes many crop species and promotes plant growth. However, the molecular mechanisms underlying F. oryzae-mediated growth promotion are still unknown. We found that F. oryzae was able to colonize Arabidopsis thaliana. The most dramatic change after F. oryzae inoculation was observed in the root architecture, as evidenced by increased lateral root growth but reduced primary root length, similar to the effect of auxin, a significant plant growth hormone. The expression of genes responsible for auxin biosynthesis, transport, and signalling was regulated in Arabidopsis roots after F. oryzae cocultivation. Indole derivatives were detected at significantly higher levels in liquid media after cocultivation compared with separate cultivation of Arabidopsis and F. oryzae. Consistently, the expression of indole biosynthetic genes was highly upregulated in F. oryzae upon treatment with Arabidopsis exudates. Global analysis of Arabidopsis gene expression at the early stage after F. oryzae cocultivation suggested that signals were exchanged to initiate Arabidopsis-F. oryzae interactions. All these results suggest that signalling molecules from Arabidopsis roots are perceived by F. oryzae and induce the biosynthesis of indole derivatives in F. oryzae, consequently stimulating Arabidopsis lateral root growth.

中文翻译：

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内生真菌Falciphora oryzae通过感测植物信号后产生吲哚衍生物来促进侧根生长。

内生真菌稻谷镰刀菌最初是从野生稻（Oryza granulata）中分离出来的，它定居在许多农作物物种中并促进植物的生长。但是，米曲霉介导的促进生长的分子机制仍是未知的。我们发现米曲霉能够在拟南芥中定殖。稻瘟病菌接种后，在根部结构中观察到了最显着的变化，这可以通过横向根部生长的增加但初级根部长度的减少来证明，这与生长素（一种重要的植物生长激素）的作用相似。米曲霉共培养后，负责生长素生物合成，转运和信号传导的基因的表达在拟南芥根中得到调节。与单独培养拟南芥和米曲霉相比，共培养后在液体培养基中检出的吲哚衍生物含量高得多。一致地，用拟南芥渗出液处理后，米曲霉中吲哚生物合成基因的表达高度上调。稻瘟病菌共培养后早期对拟南芥基因表达的整体分析表明，信号交换被启动了拟南芥-F。稻米相互作用。所有这些结果表明，来自拟南芥根的信号传导分子被米曲霉感知并诱导米曲霉中吲哚衍生物的生物合成，从而刺激了拟南芥侧根的生长。稻瘟病菌共培养后早期对拟南芥基因表达的整体分析表明，信号交换被启动了拟南芥-F。稻米相互作用。所有这些结果表明，来自拟南芥根的信号传导分子被米曲霉感知并诱导米曲霉中吲哚衍生物的生物合成，从而刺激了拟南芥侧根的生长。稻瘟病菌共培养后早期对拟南芥基因表达的整体分析表明，信号交换被启动了拟南芥-F。稻米相互作用。所有这些结果表明，来自拟南芥根的信号分子被米曲霉感知并诱导米曲霉中吲哚衍生物的生物合成，从而刺激了拟南芥侧根的生长。