LIPID BODIES PRODUCTION IN THE UNICELLULAR ALGAE SCENEDESMUS OBLICUUS IS INFLUENCED BY SORROUNDING BACTERIA

PAGNUSSAT LUCIANA; BULLÓN, MILAGROS; CASTILLO, ELIAS; CREUS, CECILIA M.; CURATTI LEONARDO

Congreso; 51 Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2015

The production of biodiesel from microalgae iscurrently seen as a possible solution to the exhaustion of fossil fuels. Uponnutrient starvation, microalgae undergo growth arrest and lipid accumulationinto newly synthesized oil bodies. Several microalgalspecies synthesize and respond to indole-3-acetic acid (IAA), but itsphysiological role remains unclear.Azospirillum brasilense is a rhizobacteria that enhances plantgrowth by the production of IAA, cytokinin, gibberellin, ethylene and nitricoxide. The aim of this work was to determine the roleof AIA in microalgae-bacteria communication on mixed consortia withrhizobacteria.Our results show that Scenedesmus oblicuus was impaired in lipid accumulation uponnutrient stress on mixed cultures with the A.brasilense mutant strain Faj009, with a 90% reduction in IAA production. Conversely, co-inoculation with A. brasilense wild type or with the Faj009pipdC strain, carryinga plasmid with the wild type version of the ipdC gene, resulted in lipidaccumulation upon nutrient stress and oil bodies? production. Onthe other hand, S. oblicuus cellscultured with the Faj009 strain remain unaltered, with intact chloroplasts andlacking of oil droplets.These results suggest that algae-bacteriacommunication influence algae physiology, and might have implications forextensive culture of microalgae.