A bacterial polysaccharide biosynthesis-related gene inversely regulates larval settlement and metamorphosis of Mytilus coruscus

Abstract

Larval settlement and metamorphosis is essential for the development of marine invertebrates. Although polysaccharides are involved in larval settlement and metamorphosis of Mytilus coruscus, the molecular basis of polysaccharides underlying this progression remains largely unknown. Here, the roles of the polysaccharide biosynthesis-related gene 01912 of Pseudoalteromonas marina ECSMB14103 in the regulation of larval settlement and metamorphosis were examined by gene-knockout technique. Compared with biofilms (BFs) of the wild-type P. marina, Δ01912 BFs with a higher colanic acid (CA) content showed a higher inducing activity on larval settlement and metamorphosis. Deletion of the 01912 gene caused an increase in c-di-GMP levels, accompanied by a decrease in the motility, an increase in cell aggregation, and overproduction of CA. Thus, the bacterial polysaccharide biosynthesis-related gene 01912 may regulate mussel settlement by producing CA via the coordination of c-di-GMP. This work provides a deeper insight into the molecular mechanism of polysaccharides in modulating mussel settlement.

Keywords:

• Mussel
• Mytilus coruscus
• colanic acid
• c-di-GMP
• larval settlement and metamorphosis
• biofilm

Acknowledgements

The authors thanked Dr. Sergey Dobretsov for his valuable comments on the manuscript. The authors also thanked Prof. Xiaoxue Wang for her proving plasmid pK18mobsacB-Ery.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by National Natural Science Foundation of China (No. 41876159, 41476131), Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (GML2019ZD0402), Key Program for International Science and Technology Cooperation Projects of Ministry of Science and Technology of China (No. 2016YFE0131900), and Program for study on genetic resources, environment and strategy of mussel culture in coast of Gouqi Island offshore.