Earthworm toxicogenomics: A renewed genome-wide quest for novel biomarkers and mechanistic insights

As sentinel species, earthworms such as Eisenia spp. and Lumbricus spp. have been considered among the best bioindicators or biomonitors for soil ecosystems owing to their close contact with the environment and essential roles in soil pedogenesis, structure, fertility and the terrestrial food chain. Earthworms have also been used extensively for assessing environmental risk and chemical toxicity in laboratory and field settings. In the past two decades, a comprehensive set of transcriptomic, proteomic, metabolomic and bioinformatic tools have been developed and applied to assess ecological impacts of contaminated soils on earthworms. In this review, we summarize recent progress made in earthworm toxicogenomics, with an emphasis on earthworm toxicotranscriptomics, examine novel biomarkers discovered and mechanistic insights gained through toxicogenomics studies, discuss currently existing technical hurdles to be resolved in order to move ahead, and finally provide some remarks on the future perspectives of this interdisciplinary and promising field.