Background and aims

Plants emit exudates into the rhizosphere under environmental stresses, influencing fungal communities. The effects of reduced light, root competition, and combined stresses on root exudates and fungal regulation are unknown.

Methods

Our experiments assessed the effects of low light (L), interspecific competition (C), and combined stresses (LC) on flavonoid exudates and rhizosphere fungal communities in the roots of Juglans mandshurica and Fraxinus mandshurica. The correlation between differential exudates and fungal communities was examined.

Result

In our study, fifty-nine exudates exhibited significant changes under single and combined stresses. Under low light, eleven exudates were upregulated and ten downregulated; under interspecific competition, ten were upregulated and four downregulated; and under combined stress, two were upregulated and thirteen downregulated. Meanwhile, nine shared exudates were upregulated and one downregulated under each stress. In addition, single and combined stress affected the composition and abundance of fungal communities in the rhizosphere. Ascomycota were synergistically affected by the combined stress, while Zygomycota and Mortierella were antagonistically affected by the combined stress in Juglans mandshurica. Exudated isorhamnetin, eriodictyol, kaempferol, vicenin, and rutin showed significant positive correlations with Ascomycota, Zygomycota, Nectriaceae, Chaetomiaceae, and Mortierella. On the other hand, apigenin, hesperidin, and kaempferol showed significant negative correlations with Sordariomycetes.

Conclusion

Low light, interspecific competition, and combined stress induce changes in flavonoid exudates that may correspond to the recruitment of potentially beneficial and the inhibition of potentially harmful fungal communities, underscoring rhizosphere adaptation.

中文翻译：

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弱光、种间竞争及其组合对胡桃根系和水曲柳根系黄酮分泌模式和根际真菌群落的影响

 背景和目标

植物在环境压力下将分泌物排放到根际，影响真菌群落。减少光照、根系竞争和综合胁迫对根系分泌物和真菌调节的影响尚不清楚。

 方法

我们的实验评估了弱光 （L） 、种间竞争 （C） 和联合胁迫 （LC） 对胡桃根系黄酮渗出物和水曲柳根际真菌群落的影响。检查了差异渗出物与真菌群落之间的相关性。

 结果

在我们的研究中，59 种渗出物在单一和联合应力下表现出显着变化。在弱光下，11 例渗出液上调，10 例下调;在种间竞争下，10 例上调，4 例下调;在综合应激下，2 例上调，13 例下调。同时，在每个应激下，9 个共享渗出物上调，1 个下调。此外，单一和综合胁迫影响了根际真菌群落的组成和丰度。子囊菌属受复合应激的协同影响，而接合菌属和被孢霉菌属受复合应激的拮抗影响。渗出的异鼠李素、 eriodictyol、山奈酚、维塞宁和芦丁与子囊菌门、接合菌门、Nectriaceae、Chaetomiaceae 和 Mortierella 呈显著正相关。另一方面，芹菜素、橙皮苷和山奈酚与索达里奥菌呈显著负相关。

 结论

弱光、种间竞争和联合应激诱导类黄酮渗出物的变化，这可能对应于潜在有益的募集和潜在有害真菌群落的抑制，强调根际适应。