Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 201602, China.
University of Chinese Academy of Sciences, 100049, Beijing, China.
ISME J. 2022 Nov;16(11):2622-2632. doi: 10.1038/s41396-022-01288-7. Epub 2022 Jul 16.
Flavonoids are stress-inducible metabolites important for plant-microbe interactions. In contrast to their well-known function in initiating rhizobia nodulation in legumes, little is known about whether and how flavonoids may contribute to plant stress resistance through affecting non-nodulating bacteria. Here we show that flavonoids broadly contribute to the diversity of the Arabidopsis root microbiome and preferentially attract Aeromonadaceae, which included a cultivable Aeromonas sp. H1 that displayed flavonoid-induced chemotaxis with transcriptional enhancement of flagellum biogenesis and suppression of fumarate reduction for smooth swims. Strain H1 showed multiple plant-beneficial traits and enhanced plant dehydration resistance, which required flavonoids but not through a sudden "cry-for-help" upon stress. Strain H1 boosted dehydration-induced HO accumulation in guard cells and stomatal closure, concomitant with synergistic induction of jasmonic acid-related regulators of plant dehydration resistance. These findings revealed a key role of flavonoids, and the underlying mechanism, in mediating plant-microbiome interactions including the bacteria-enhanced plant dehydration resistance.
类黄酮是一种应激诱导的代谢物，对植物-微生物相互作用很重要。与它们在豆科植物中诱导根瘤菌结瘤的众所周知的功能形成鲜明对比的是，人们对于类黄酮是否以及如何通过影响非结瘤细菌来促进植物的抗胁迫能力知之甚少。在这里，我们表明类黄酮广泛有助于拟南芥根微生物组的多样性，并优先吸引气单胞菌科，其中包括可培养的气单胞菌 H1，它表现出类黄酮诱导的趋化性，同时转录增强鞭毛生物发生并抑制延胡索酸还原以实现顺畅游动。菌株 H1 表现出多种植物有益特性，并增强了植物的脱水抗性，这需要类黄酮，但不是通过在胁迫下突然“呼救”来实现。菌株 H1 增加了保卫细胞中脱水诱导的 HO 积累和气孔关闭，同时协同诱导与植物脱水抗性相关的茉莉酸相关调节剂。这些发现揭示了类黄酮在介导植物-微生物相互作用中的关键作用，包括细菌增强植物脱水抗性的作用机制。
