海假交替单胞菌fliC-02330基因缺失影响生物被膜形成及厚壳贻贝幼虫附着变态

Deletion of fliC-02330 from Pseudoalteromonas marina affects the biofilm formation and the settlement and metamorphosis of Mytilus coruscus

摘要:

【背景】假交替单胞菌属是一种广泛分布于海洋环境的革兰氏阴性细菌，存在于海底沉积物中，能分泌大量的胞外产物形成海洋微生物被膜，从而诱导海洋无脊椎动物的附着。【目的】探究海假交替单胞菌鞭毛蛋白fliC基因对生物被膜形成及厚壳贻贝诱导活性的影响。【方法】通过基因敲除构建海假交替单胞菌fliC-02330基因缺失突变菌，研究突变菌和野生菌菌落形态、生物被膜形成能力、胞外物质以及对厚壳贻贝幼虫附着变态的诱导能力等的差异性。【结果】与野生菌相比，突变菌菌落表型出现褶皱，运动能力下降，形成被膜膜厚增加，以及对幼虫附着变态诱导活性下降。共聚焦扫描发现，fliC-02330基因缺失突变菌胞外多糖含量下降，而蛋白含量上升。【结论】海假交替单胞菌鞭毛蛋白fliC-02330基因缺失促进生物被膜形成，但抑制厚壳贻贝幼虫附着变态。本研究为探究细菌鞭毛蛋白基因与厚壳贻贝幼虫的作用机制，以及后续进一步探索微生物参与海洋无脊椎动物附着变态提供一定的理论依据。

Abstract:

[Background] Pseudoalteromonas is a group of Gram-negative bacteria ubiquitous in the marine environment.They exist in the seabed sediments and can secrete a large amount of extracellular products to form a biofilm,which induces the attachment of invertebrates.[Objective] To explore the effect of fliC-02330 deletion from Pseudoalteromonas marina on the biofilm formation and the activity of Mytilus coruscus.[Methods] We constructed the fliC-02330-deleted mutant of P. marina by gene knockout and then compared the phenotype,the biofilm-forming ability,and the effect on settlement and metamorphosis of M. coruscus between the mutant and the wild-type strain.Confocal laser scanning microscopy (CLSM) was conducted to detect changes in the content of extracellular products in the biofilm.[Results]Compared with the wild-type strain,the mutant showed wrinkled colony,weakened motility,thickened biofilm,and decreased activity of inducing the larval settlement and metamorphosis of M. coruscus.CLSM revealed that the fliC-02330-deleted mutant had decreased extracellular polysaccharide content and increased protein content.[Conclusion]The fliC-02330-deleted mutant has increased biofilm-forming ability and can inhibit the settlement and metamorphosis of M. coruscus larvae.This study provides a theoretical basis for exploring the mechanism of bacterial flagellin gene and the role of microorganisms in the settlement and metamorphosis of marine invertebrates.