Agriculture Victoria Research, Department of Economic Development, Jobs, Trade and Resources, 5 Ring Rd, Bundoora, Victoria 3083, Australia.
Agriculture Victoria Research, Department of Economic Development, Jobs, Trade and Resources, 5 Ring Rd, Bundoora, Victoria 3083, Australia; School of Applied Systems Biology, La Trobe University, Bundoora, Victoria 3083, Australia.
Sci Total Environ. 2019 Feb 15;651(Pt 1):1627-1638. doi: 10.1016/j.scitotenv.2018.09.249. Epub 2018 Sep 20.
The suppression of soilborne crop pathogens such as Rhizoctonia solani AG8 may offer a sustainable and enduring method for disease control, though soils with these properties are difficult to identify. In this study, we analysed the soil metabolic profiles of suppressive and non-suppressive soils over 2 years of cereal production. We collected bulk and rhizosphere soil at different cropping stages and subjected soil extracts to liquid chromatography-mass spectrometry (LC-MS) and proton nuclear magnetic resonance spectroscopy (H NMR) analyses. Community analyses of suppressive and non-suppressive soils using principal component analyses and predictive modelling of LC-MS and NMR datasets respectively, revealed distinct biochemical profiles for the two soil types with clustering based on suppressiveness and cropping stage. NMR spectra revealed the suppressive soils to be more abundant in sugar molecules than non-suppressive soils, which were more abundant in lipids and terpenes. LC-MS features that were significantly more abundant in the suppressive soil were identified and assessed as potential biomarkers for disease suppression. The structures of a potential class of LC-MS biomarkers were elucidated using accurate mass data and MS fragmentation spectrum information. The most abundant compound found in association with suppressive soils was confirmed to be a macrocarpal, which is an antimicrobial secondary metabolite. Our study has demonstrated the utility of environmental metabolomics for the study of disease suppressive soils, resulting in the discovery of a macrocarpal biomarker for R. solani AG8 suppressive soil which can be further studied functionally in association with suppression pot trials and microbial isolation studies.
抑制土传作物病原菌，如立枯丝核菌 AG8，可能为病害防治提供一种可持续且持久的方法，尽管具有这些特性的土壤很难识别。在这项研究中，我们分析了 2 年谷物生产过程中抑制性和非抑制性土壤的土壤代谢特征。我们在不同的种植阶段采集了大量和根际土壤，并对土壤提取物进行了液相色谱-质谱（LC-MS）和质子核磁共振波谱（H NMR）分析。通过主成分分析和对 LC-MS 和 NMR 数据集的预测建模，分别对抑制性和非抑制性土壤进行群落分析，揭示了这两种土壤类型具有明显不同的生化特征，聚类基于抑制性和种植阶段。NMR 光谱显示，抑制性土壤中的糖分子比非抑制性土壤更丰富，而非抑制性土壤中则含有更多的脂质和萜类化合物。鉴定出在抑制性土壤中丰度显著更高的 LC-MS 特征，并将其评估为病害抑制的潜在生物标志物。使用精确质量数据和 MS 碎片光谱信息阐明了与抑制性土壤相关的潜在 LC-MS 生物标志物的结构。与抑制性土壤相关的最丰富化合物被确认为一种大卡帕，这是一种具有抗菌作用的次生代谢物。我们的研究表明，环境代谢组学在研究抑制性土壤方面具有实用性，发现了一种与立枯丝核菌 AG8 抑制性土壤相关的大卡帕生物标志物，可进一步通过与抑制性盆栽试验和微生物分离研究相关联的功能研究进行研究。
