PALA2024

This project will investigate a new Antarctic marine partnership between the ascidian (“sea squirt”) Synoicum adareanum and its microbiome, which includes a specific relationship with the bacterium Candidatus Synoicihabitans palmerolidicus. This bacterium produces the natural product palmerolide A (palA), an in vitro inhibitor of the enzyme V-type H+-ATPase (VHA). The objectives include: (i) Determining the microbiome composition, metabolome complexity, palA levels, and mitochondrial DNA sequence of S. adareanum morphotypes at sites in the Antarctic Peninsula and in McMurdo Sound, (ii) Characterizing the Synoicum microbiome using a multiomics strategy, and (iii) Assessing the potential for co-occurrence of Ca. S. palmerolidicus-palAVHA in host tissues and exploring the role of palA in modulating VHA activity in vivo and its effects on ascidian-microbe ecophysiology. Through a coupled study of palA-producing and non-producing S. adareanum specimens, we will characterize structural and functional features of the ascidian microbiome metagenome to better understand the relationship between predicted secondary metabolite pathways and whether they are expressed in situ using a paired metatranscriptome sequencing and secondary metabolite detection strategy. Combined with tissue co-localization results, functional ecophysiological assays aim to determine the roles that the natural product plays in the host ecology in its native Antarctic seafloor habitat.