Coastal metamobilome diversity.
Supervisor: Henk Bolhuis (NIOZ)
Mobile genetic elements permeate the marine environment, influencing the flow of genes and evolution within microbial communities by enabling horizontal gene transfer. They are particularly relevant for the spread of antibiotic, antimicrobial and heavy metal resistance, especially in biofilms. Metamobilomics analyzes the genetic information encoded on the circular mobile genetic elements in a community of organisms. Using a bioinformatics approach, this study characterized and visualized the metamobilome, with an emphasis on plasmids, associated with the coastal macroalgae Ulva from the Netherlands and Spain and two cultured microalgae, Tisochrysis lutea and Chlorella vulgaris. The diversity of the associated microbial communities was also described by matching detected genes with a potential host based on protein similarity. The microalgal samples contained larger plasmids and generally less viruses than the Ulva samples (USO and UTV). Replication and maintenance genes detected included repE, repB, repA, trfA, xerC, parA and multiple toxin-antitoxin systems. Mobilization genes (e.g., mobA, pre) were ubiquitous, although origin of transfer (oriT) regions were not as frequently found. Genes involved in conjugation were detected (e.g., virB4, traG), but no plasmids encoded all the necessary genes for replication, mobilization and conjugation. ant1 was the only gene identified related to antibiotic resistance. In all samples, Pseudomonadota dominated the community, followed by Bacteroidota and Bacillota. Rhodobacterales was the dominant order in all samples. The genera most frequently detected included Sulfitobacter (USO and T. lutea), Vibrio (UTV) and Acinetobacter (C. vulgaris). This study will be expanded to analyze the metamobilome associated with a cyanobacterial mat and a salt marsh over multiple seasons.