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.

中文翻译：

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细菌多糖生物合成相关基因反向调控贻贝幼虫沉降和变态

摘要 幼体的沉降和变态对于海洋无脊椎动物的发育至关重要。尽管多糖参与了贻贝的幼虫沉降和变态，但这种进展背后的多糖的分子基础仍然很大程度上未知。在这里，通过基因敲除技术检查了 Pseudoalteromonas marina ECSMB14103 的多糖生物合成相关基因 01912 在幼虫沉降和变态调节中的作用。与野生型 P. marina 的生物膜 (BFs) 相比，具有较高可拉酸 (CA) 含量的 Δ01912 BFs 对幼虫沉降和变态具有更高的诱导活性。01912 基因的缺失导致 c-di-GMP 水平的增加，伴随着运动性的降低、细胞聚集的增加和 CA 的过度产生。因此，细菌多糖生物合成相关基因 01912 可能通过 c-di-GMP 的协调产生 CA 来调节贻贝的沉降。这项工作对多糖调节贻贝沉降的分子机制提供了更深入的了解。