UV-B resistance in a bacterial strain isolated from High Altitude Andean Wetlands: the pigment role

Abstract

In order to test UV-B radiation resistance of bacterioplankton communities from High Altitude Andean Wetlands, water samples were exposed 24 h to UV-B radiation (DOSIS: 166 kJ/m2). A red bacterial strain related to Serratia sp. Vil 11, was able to resist more than 6 h under UV-B treatment. In this work, we analyze the photoprotective pigment role in Serratia sp. Vil 11 employing a wild type strain (red) and a non-pigmented mutant. In addition, we also performed the identification of the pigment content by HPLC and it cellular localization by confocal microscopy. In the absence of pigment production, Serratia sp. Vil 11 was significantly more susceptible to UV-B stress. Pigmented cells survived high UV-B exposure (DOSIS: 7 kJ/m2), around 10 fold compared to the non-pigmented mutant cells. The HPLC analyses showed a sole peak corresponding to prodigiosine pigment and the confocal microscopy analysis showed an extracellular location of the pigment distribution suggesting that it would be play an important role in primary protection against UV-B radiation.