Environmental proteomics: A long march in the pedosphere

Environmental proteomics, the study of the expression profile of proteins extracted directly from living organisms and some stabilized extracellular proteins present in environmental samples, is a developing branch of soil science since the seminal papers appeared twenty years ago. Soil microbial communities hold the key to understanding terrestrial biodiversity; they are extremely complex and their physiological responses to dynamic environmental parameters are under-characterized. Therefore, the slow development of environment-related proteomic databases, and the high chemical reactivity of environmental matrices hamper the extraction, quantification, and characterization of proteins; and soil proteomics remains still in its infancy. We underscore the main achievements of environmental proteomics focusing on soil ecosystems, and we identify technical gaps that need to be bridged in the context of relevant ecological concepts that have received little attention in the development of proteomics methods. This analysis offers a new framework of research of soil proteomics toward improved understanding of the causal linkages between the structure and function of the soil microbiome, and a broader grasp of the sensitivity of terrestrial ecosystems to environmental change.