Development of Massive Molecular Biomarker Analysis (“Biomarkomics”) in Non-model Species: The Transcriptome of Rhinella arenarum (Anura, Bufonidae) Larvae Exposed to Organophosphorus Pesticides as a Case Example

Abstract

The development of massive sequencing technologies has led to an impressive increase in data acquisition capacity and analysis. The study of differential expression of genes (DEG) in species exposed to contaminants using whole transcriptomics enables a response pattern as a massive molecular biomarker fingerprint. This biomarkomic approach has been recently applied to the autochthonous, non-model amphibian Rhinella arenarum exposed to organophosphorus pesticides. The whole transcriptome study enabled the annotation of approximately 57 thousand gene sequences, an excellent starting point considering that the R. arenarum genome remains unknown. In parallel, massive biomarkomic analysis has confirmed that a few top-regulated genes are commonly affected by contaminant exposure, while more genes are specifically affected by either organophosphorus pesticide. Interestingly, none of the target or responding genes typically recognized for organophosphorus pesticides at the biochemical or molecular levels were found among the top-regulated genes in the biomarkomic analysis. This fact was also confirmed by a hypothesis-driven DEG analysis focused on these recognized targets for organophosphorus effects and responses, except for a very few genes related to detoxification, metabolism, and regulation. Our efforts are now directed to long-noncoding RNA biomarkomics as well as the extension of our transcriptomic studies to other contaminants and other aquatic autochthonous species.