Alkane Monooxygenase Gene Diversity in Subantarctic Marine Sediments

GUIBERT, L.M.; LOVISO, C.L.; MARCOS, M.S.; DIONISI, H.M; LOZADA, M.

Puerto Madryn

Congreso; XLVI Reunion Anual de la Sociedad Argentina de Investigacion en Bioquimica y Biologia Molecular; 2010

Culture independent methods were used to characterize bacterial populations associated with aliphatic hydrocarbon biodegradation in cold marine environments, using functional genes as targets. Alkane monooxygenase (alkB) gene libraries were constructed using DNA extracted from sediments of a chronically-polluted site in Ushuaia Bay, Tierra del Fuego. PCR reactions were carried out using degenerate primers in order to cover a wide range of alkB gene types. More than 250 clones were analyzed by RFLP, and representatives of each restriction pattern were sequenced. Phylogenetic analysis revealed a high diversity of alkB genes, including novel divergent sequences as well as members of all known variants of alkB genes. Particularly, two groups of genes moderately related to the genus Alcanivorax, an obligate oil degrading marine bacterium, were highly frequent in libraries from samples obtained in 2006-2008, suggesting that this important group is a stable member of the microbial community at this site. Moreover, these gene variants were related to the ones previously found in Alcanivorax isolates from northern Patagonia, indicating they are widespread in the region. Currently, the effect of crude oil exposure on alkB gene diversity is being studied using an experimental system, to test the effect of the addition of nutrients, a commonly used bioremediation treatment.