Abstract
Soil covers most of Earth’s continental surface and is fundamental to life-sustaining processes such as agriculture. Given its rich biodiversity, soil is also a major source for natural product drug discovery from soil microorganisms. However, the study of the soil small molecule profile has been challenging due to the complexity and heterogeneity of this matrix. In this study, we implemented high-resolution liquid chromatography–tandem mass spectrometry and large-scale data analysis tools such as molecular networking to characterize the relative contributions of city, state and regional processes on backyard soil metabolite composition, in 188 soil samples collected from 14 USA States, representing five USA climate regions. We observed that region, state and city of collection all influence the overall soil metabolite profile. However, many metabolites were only detected in unique sites, indicating that uniquely local phenomena also influence the backyard soil environment, with both human-derived and naturally-produced (plant-derived, microbially-derived) metabolites identified. Overall, these findings are helping to define the processes that shape the backyard soil metabolite composition, while also highlighting the need for expanded metabolomic studies of this complex environment.
Highlights
Soil is a highly complex and diverse mixture of minerals and organic material ubiquitous on the Earth’s surface [1]
Metabolites were analyzed from 188 backyard soil samples collected from 45 cities, across 14 states, and representing five of the United States National Oceanic and Atmospheric Administration (NOAA)
We report the metabolomic analysis of 188 soils from across the USA
Summary
Soil is a highly complex and diverse mixture of minerals and organic material ubiquitous on the Earth’s surface [1]. Its composition is influenced by large-scale factors such as climate, temperature and humidity, and local phenomena such as human activity. Soil composition plays an important role in the regulation of many processes, such as plant growth, water systems and microorganism biology [2,3]. The biodiversity and microbial competition in the soil is a rich source for natural product drug discovery [1,4,5]. Small molecules (metabolites) are major effectors of biological function, reflecting the active phenotype resulting from an environment’s genetic potential [6]. The study of the soil small molecule profile has been limited by Metabolites 2020, 10, 86; doi:10.3390/metabo10030086 www.mdpi.com/journal/metabolites
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