Purpose

Arbuscular mycorrhizal fungi (AMF) play important roles in agriculture because of their ability to improve plant resilience against abiotic and biotic stresses. AMF as a technology to promote a more sustainable agriculture holds great potential, yet many factors affect the efficiency of this plant-microbe symbiosis leading to inconsistency in performance. The beneficial symbiosis between plants and AM fungi, also-known-as the mycorrhiza is promoted by strigolactones (SLs), carotenoid derivatives active as phytohormones and rhizosphere signals. Natural SLs are effective at extremely low concentrations, however their bioavailability in soil is scarce because their biosynthesis and exudation are plant-regulated, their degradation is fast and their mobility in soil is limited.

Methods

Through a broad synthetic chemistry approach, we explored how structurally diverse SL derivatives could improve hyphal branching of Gigaspora spp AMF under laboratory conditions and thus possibly boost mycorrhization into soil.

Results

We tested twenty-six different derivatives and we could highlight structural enhancements to promote hyphal branching of in vitro germinated AMF spores at equal, and in some cases higher levels compared to natural SLs. A subset of these derivatives was tested for bioavailability, but no clear correlation was found with their activity on hyphal branching.

Conclusion

This study suggests that we could use a targeted, chemical-design approach to synthetize new SL derivatives to enable enhanced promotion of mycorrhization and potentially enhanced bioavailability compared to natural SLs. Due to the roles of AMF in crop production systems, these results highlight new innovative approaches to promote sustainable agriculture.

中文翻译：

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具有可持续农业应用潜力的新型合成抗生内酯模拟物的效率和生物利用度

目的

丛枝菌根真菌（AMF）在农业中起着重要作用，因为它们具有提高植物抵抗非生物和生物胁迫的能力。AMF作为一种促进更可持续农业发展的技术具有巨大的潜力，但是许多因素影响这种植物-微生物共生的效率，从而导致性能不一致。植物与AM真菌（也称为菌根）之间的有益共生作用是通过Strigolactones（SLs），作为植物激素和根际信号活跃的类胡萝卜素衍生物来促进的。天然SL在极低的浓度下仍然有效，但是由于其生物合成和渗出受植物调节，它们的降解速度快且在土壤中的移动性受到限制，因此它们在土壤中的生物利用度稀缺。

方法

通过广泛的合成化学方法，我们探索了结构上不同的SL衍生物如何在实验室条件下改善Gigaspora spp AMF的菌丝分支，从而可能促进菌根进入土壤。

结果

我们测试了26种不同的衍生物，我们可以强调结构增强作用，以促进体外萌发的AMF孢子的菌丝分支，其数量与天然SL相当，在某些情况下甚至更高。测试了这些衍生物的一个子集的生物利用度，但未发现它们与菌丝分支的活性有明确的相关性。

结论

这项研究表明，与天然SL相比，我们可以使用针对性的化学设计方法来合成新的SL衍生物，从而能够增强菌根的促进作用并潜在地提高生物利用度。由于AMF在农作物生产系统中的作用，这些结果突出了促进可持续农业的新的创新方法。