Genomic insights into indole-3-acetic acid catabolism in the marine algae-associated bacterium, Marinomonas sp. NFXS50

Auxins, mainly in the form of indole-3-acetic acid (IAA), regulate several aspects of plant and algal growth and development. Consequently, plant and algae-associated bacteria developed the ability to modulate IAA levels, including IAA catabolism. In this work, we present and analyse the genome sequence of the IAA-degrading and marine algae-associated bacterium, <i>Marinomonas</i> sp. NFXS50, analyse its IAA catabolism gene cluster and study the prevalence of IAA catabolism genes in other <i>Marinomonas</i> genomes. Our findings revealed the presence of homologs of the <i>Pseudomonas iac</i> gene cluster, implicated in IAA catabolism, in the genome of strain NFXS50; however, differences were observed in the content and organization of the <i>Marinomonas iac</i> gene cluster when compared to that of the model <i>iac</i>-containing <i>Pseudomonas putida</i> 1290. These variations suggest potential adaptations in the IAA catabolism pathway, possibly influenced by substrate availability and evolutionary factors. The prevalence of <i>iac</i> genes across several <i>Marinomonas</i> species underscores the significance of IAA catabolism in marine environments, potentially influencing plant/algae-bacteria interactions. This study provides novel insights into the IAA catabolism in <i>Marinomonas</i>, laying the groundwork for future investigations into the role of <i>iac</i> genes in <i>Marinomonas</i> physiology and the regulation of marine plant/algae-bacteria interactions.