Lancaster Environment Centre, Lancaster University, Lancaster, UK.
Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool, UK.
Commun Biol. 2021 May 3;4(1):516. doi: 10.1038/s42003-021-02037-w.
Drought imposes stress on plants and associated soil microbes, inducing coordinated adaptive responses, which can involve plant-soil signalling via phytohormones. However, we know little about how microbial communities respond to phytohormones, or how these responses are shaped by chronic (long-term) drought. Here, we added three phytohormones (abscisic acid, 1-aminocyclopropane-1-carboxylic acid, and jasmonic acid) to soils from long-term (25-year), field-based climate treatments to test the hypothesis that chronic drought alters soil microbial community responses to plant stress signalling. Phytohormone addition increased soil respiration, but this effect was stronger in irrigated than in droughted soils and increased soil respiration at low phytohormone concentrations could not be explained by their use as substrate. Thus, we show that drought adaptation within soil microbial communities modifies their responses to phytohormone inputs. Furthermore, distinct phytohormone-induced shifts in microbial functional groups in droughted vs. irrigated soils might suggest that drought-adapted soil microorganisms perceive phytohormones as stress-signals, allowing them to anticipate impending drought.
干旱对植物及其相关土壤微生物造成压力，诱导出协调的适应反应，这可能涉及通过植物激素进行植物-土壤信号传递。然而，我们对微生物群落如何对植物激素做出反应，以及这些反应如何受到慢性（长期）干旱的影响知之甚少。在这里，我们向长期（25 年）田间气候处理的土壤中添加了三种植物激素（脱落酸、1-氨基环丙烷-1-羧酸和茉莉酸），以检验慢性干旱是否会改变土壤微生物群落对植物胁迫信号的反应这一假设。植物激素的添加增加了土壤呼吸，但这种效应在灌溉土壤中比在干旱土壤中更强，而低浓度植物激素增加土壤呼吸的现象不能用它们作为基质来解释。因此，我们表明，土壤微生物群落内部的干旱适应会改变它们对植物激素输入的反应。此外，干旱和灌溉土壤中不同的植物激素诱导的微生物功能群变化可能表明，适应干旱的土壤微生物将植物激素视为应激信号，使它们能够预测即将到来的干旱。
