Cultivation of gut microorganisms of the marine ascidian reveals their potential roles in the environmental adaptation of their host.

UNLABELLED

It has long been known that abundant symbiotic bacteria exist in the tunic and gut of marine ascidians, and that these play crucial roles in host development, physiological metabolism, and environmental adaptation. However, the identity, roles and functions of these symbiotic bacteria are known for only a few strains. In this study, we isolated and cultivated 263 strains of microorganisms from the intestine of the marine ascidian through a combination of aerobic and anaerobic culture approaches. Most cultivated species, both aerobic and anaerobic, from ascidian stool samples belonged to the genus based on 16S rDNA sequencing identification and phylogenetic assays. The distribution of cultured bacteria varied with seasonal changes in environmental conditions. To explore the functions of cultured bacteria, we screened out a strain of sp. whose extracts showed high antibacterial activity against aquatic pathogens. These findings revealed the potential roles of gut microorganisms in ascidian defense and environmental adaptation, thus providing insights into the interaction and co-evolution between gut bacteria and their hosts.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s42995-022-00131-4.