Bacteroidetes bacteria, important players in the marine sponge larval development process.

Area of Science:

• Marine microbiology
• Symbiotic relationships
• Invertebrate development

Background:

• Bacteroidetes bacteria are common symbionts in marine sponges.
• The specific roles of these bacteria in sponge development remain largely unknown.
• Understanding these interactions is key to marine ecology and evolution.

Purpose of the Study:

• To investigate the influence of bacteria isolated from the sponge Tedania sp. on sponge larval settlement.
• To identify the mechanisms by which these bacteria promote settlement.
• To explore the potential for co-evolution between sponges and their associated bacteria.

Main Methods:

• Isolation and culturing of thirteen bacterial species from Tedania sp.
• Assaying bacterial effects on sponge larval settlement rates.
• Analyzing bacterial strategies including biofilm formation, secretion of hydrosoluble molecules, and production of extracellular vesicles (EVs).
• Utilizing fluorescence microscopy to track EV migration within sponge larvae.

Main Results:

• All thirteen bacterial species significantly promoted sponge larval settlement (30.00-53.33% increase).
• Biofilms enhanced settlement to 56.67-63.33%; hydrosoluble molecules to 59.17%.
• Extracellular vesicles (EVs) yielded the highest settlement rates (up to 86.67%) and were observed migrating into sponge larvae.

Conclusions:

• Bacteroidetes bacteria play a significant role in promoting sponge larval settlement and development.
• Bacterial extracellular vesicles (EVs) are a key mechanism facilitating this interaction.
• These findings support the hypothesis of reciprocal adaptive co-evolution between marine sponges and their microbial communities.