Dundore-Arias José Pablo, Castle Sarah C, Felice Laura, Dill-Macky Ruth, Kinkel Linda L
Department of Biology and Chemistry, California State University, Monterey Bay, Seaside, CA, United States.
Department of Plant Pathology, University of Minnesota, Saint Paul, MN, United States.
Front Mol Biosci. 2020 Jan 9;6:151. doi: 10.3389/fmolb.2019.00151. eCollection 2019.
Soil nutrient amendments are recognized for their potential to improve microbial activity and biomass in the soil. However, the specific selective impacts of carbon amendments on indigenous microbiomes and their metabolic functions in agricultural soils remain poorly understood. We investigated the changes in soil chemical characteristics and phenotypes of communities following carbon amendments to soil. Mesocosms were established with soil from two field sites varying in soil organic matter content (low organic matter, LOM; high organic matter, HOM), that were amended at intervals over nine months with low or high dose solutions of glucose, fructose, malic acid, a mixture of these compounds, or water only (non-amended control). Significant shifts in soil chemical characteristics and antibiotic inhibitory capacities of indigenous were observed in response to carbon additions. All high dose carbon amendments consistently increased soil total carbon, while amendments with malic acid decreased soil pH. In LOM soils, higher frequencies of inhibitory phenotypes of the two plant pathogens, and , were observed in response to soil carbon additions. Additionally, to determine if shifts in functional characteristics correlated with microbiome composition, we investigated whether shifts in functional characteristics of soil correlated with composition of soil bacterial communities, analyzed using 16S rRNA gene sequencing. Regardless of dose, community composition differed significantly among carbon-amended and non-amended soils from both sites. Carbon type and dose had significant effects on bacterial community composition in both LOM and HOM soils. Relationships among microbial community richness (observed species number), diversity, and soil characteristics varied among soils from different sites. These results suggest that manipulation of soil resource availability has the potential to selectively modify the functional capacities of soil microbiomes, and specifically to enhance pathogen inhibitory populations of high value to agricultural systems.
土壤养分改良剂因其改善土壤微生物活性和生物量的潜力而受到认可。然而，碳改良剂对农业土壤中本土微生物群落及其代谢功能的具体选择性影响仍知之甚少。我们研究了向土壤添加碳后土壤化学特性和群落表型的变化。使用来自两个土壤有机质含量不同的田间地点（低有机质，LOM；高有机质，HOM）的土壤建立了中宇宙，在九个月的时间里，每隔一段时间用低剂量或高剂量的葡萄糖、果糖、苹果酸、这些化合物的混合物或仅用水（未改良对照）进行改良。观察到土壤化学特性和本土微生物的抗生素抑制能力因添加碳而发生显著变化。所有高剂量碳改良剂均持续增加土壤总碳，而苹果酸改良剂则降低土壤pH值。在LOM土壤中，添加土壤碳后观察到两种植物病原体（和）抑制表型的频率更高。此外，为了确定微生物功能特性的变化是否与微生物群落组成相关，我们研究了土壤微生物功能特性的变化是否与土壤细菌群落组成相关，使用16S rRNA基因测序进行分析。无论剂量如何，两个地点的碳改良土壤和未改良土壤之间的群落组成均存在显著差异。碳类型和剂量对LOM和HOM土壤中的细菌群落组成均有显著影响。不同地点土壤中微生物群落丰富度（观察到的物种数量）、多样性和土壤特性之间的关系各不相同。这些结果表明，操纵土壤资源可用性有可能选择性地改变土壤微生物群落的功能能力，特别是增强对农业系统具有高价值的病原体抑制种群。
