QUORUM SENSING IN CORAL-ASSOCIATED MARINOBACTER AND ITS POTENTIAL FOR MODULATING ALGAL GROWTH AND IRON ACQUISITION

<p dir="ltr">Symbiodiniaceae-microbe interactions within coral reefs have significant impact to the health and functioning of coral systems, yet a wide knowledge gap remains on how microbes modulate algal physiology and growth. Here we investigate the potential of quorum sensing (QS), on regulating algal growth and iron acquisition in the key Symbiodiniaceae-associated bacteria, Marinobacter. We did not find evidence of the production of Acyl-homoserine lactones (AHLs), the most common QS molecules used by bacteria, nor quorum quenching molecules in Marinobacter. Interestingly, genomic analysis of Marinobacter revealed the presence of two gene homologs involved in the biosynthesis of the QS signaling molecules: Pseudomonas Quinolone Signal (PQS) and Diffusible Signaling Factor (DSF). Further genomic and transcriptomic investigations also revealed the probable role of QS in regulating iron acquisition and biosynthesis of algal growth hormone, IAA. By exploring potential interactions between QS, iron and phytohormones, we suggest that QS may play a role in beneficial processes and propose Marinobacter as a candidate for algal growth-promoting bacteria (AGPB).</p>