Metagenomic and metatranscriptomic responses of natural oil degrading bacteria in the presence of dispersants

“…The majority of highly abundant transporters in Corexit treatments were amino acid/amide ABC transporters, with about half of them specifically branched-chain amino acid (BCAA) transporters. A similar enrichment of ABC transporter genes and/or transcripts was previously reported for seawater microcosms amended with Corexit and oil or bitumen [8], petroleum-contaminated microbial mats [88], dibutyl phthalate-contaminated black soils [89], and in Sphingomonas sp. GY2B during Tween 80-enhanced phenanthrene degradation [90].…”

“…TT1 cells with their environment, as evidenced by upregulated efflux pumps, other transmembrane transporter systems, chemotactic motility, and changed biofilm formation behavior (Figure 3B). Similar trends were also observed in two recent metatranscriptomic studies on Corexit affecting seawater microbial communities [8,82] and in situ analysis from the DWH subsurface plume [83], although it remains unclear to what extent the plume metatranscriptomic data were influenced by Corexit and/or oil exposure.…”

“…Oil pollution in the marine environment quickly triggers a number of microbial responses, including a broad range of activities: (1) chemotaxis, either away from toxic hydrocarbons or towards them, (2) efflux mechanisms to facilitate secretion of small hydrocarbons that may enter bacterial cells by passive transport, together with secretion systems to transport, proteins (toxins and extracellular enzymes) or biosurfactants outside the cell, (3) death and lysis of sensitive organisms which releases a pool of organic material available for the oil-tolerant and primary or secondary oil-degrading organisms, (4) adhesion to and biofilm formation on oil droplets and signaling between the biofilm forming cells, (5) an increase in nutrient transport and processes to generate available nitrogen, phosphorous and sulfur for growth on carbon-rich and nutrient-poor oil components, and (6) biosurfactant synthesis (Van Hamme, Singh et al 2003, Rivers, Sharma et al 2013, Joye, Kleindienst et al 2016, Parales and Ditty 2018. Indeed, most of these processes, also reported in recent large scale metatranscriptomic studies (Tremblay, Yergeau et al 2017, Tremblay, Fortin et al 2019, were represented in the upregulated genes in our dataset (Table S7). However, most of them were also increasing in expression levels in the control tank (Figure 8).…”