Differential Expression of Genes Involved in Utilization of Benzo(a)Pyrene in Burkholderia vietnamiensis G4 Strain

Polyaromatic Hydrocarbons (PAH) are recalcitrant pollutants that are among the major Petroleum by-products. Among them, benzo(a)pyrene receives special attention as it is carcinogenic and highly insoluble, being really difficult to decompose with conventional treatments. Wastewater treatment plants (WWTP), often use biological techniques such as activated sludge, that rely on microorganisms to degrade organic compounds. Burkholderia genus is known for its biodegradation ability and have been used as study model. Using transcripts and mRNA analyses, one can find out genomic regions and functions involved in this aptitude. In this work we used the model strain B. vietnamiensis G4 aiming to find genes that are differentially expressed in the presence of benzo(a)pyrene. Six transcriptomes where generated from each experimental unit in order to compare gene expression and infer which genes are involved in benzo(a)pyrene degradation pathways. Thirty-six genes were differentially expressed in the group exposed to benzo(a)pyrene, most of them involved in catalytic activity. The most significant genomic regions are: phenylacetic acid degradation protein paaN involved in degradation of organic compounds to obtain energy, oxidoreductase FAD-binding subunit in the regulation of electrons within groups of dioxygenase enzymes, with potential to break benzene rings, and glutamic semialdehyde dehydrogenase, a region described as responsible for the ability of phenol degradation. These candidate genes are now target to new studies aiming optimization of treatment processes.