Recently, Shanghai Ocean University, together with the University of Algarve (Portugal), Shanghai Maritime University and other teams, published online in the international journal Corrosion Science (CAS Zone 1, JCR Q1, IF: 10.3) an important research paper entitled Polar marine biocorrosion and biofouling processes mediated by the trimeric autotransporter adhesin of Psychrobacter cibarius, which reveals for the first time the dual molecular mechanism by which polar marine bacteria, through secretion of the trimeric autotransporter adhesin YadA protein, simultaneously drive corrosion and biofouling.
Polar seas are a key frontier for global resource development and strategic competition, and they impose harsh service challenges on marine engineering materials. The coupled effect of biofouling and corrosion induced by bacterial biofilms is a key biological cause that accelerates material degradation. However, a clear understanding of the molecular mechanisms by which polar marine bacteria mediate this degradation process is still lacking.
Taking Psychrobacter cibarius, a psychrophilic bacterium widely distributed in polar seas, as the research subject, the team found that — unlike common temperate marine bacteria (Pseudoalteromonas marina) — it aggravates the corrosion degradation of low-temperature steel (EH40) and has a stronger induction rate of settlement and metamorphosis in the larvae of the typical macrofouler, the mussel. Analysis of why the extracellular products secreted by the biofilm accelerate corrosion and fouling showed that there is no significant difference between the extracellular polysaccharides and extracellular lipids of the polar psychrophilic bacterium and those of temperate bacteria; however, its extracellular protein content is far higher than that of temperate bacteria. To further investigate whether polar psychrophilic bacteria possess a specific functional protein that distinguishes them from mesophilic bacteria and causes this phenomenon, whole-genome sequencing and comparative genomics revealed that the gene encoding the trimeric autotransporter adhesin YadA is present only in polar marine bacteria and absent from the temperate control strains.
The team then used gene knockout technology to specifically knock out gene 1308, which is responsible for anchoring YadA to the bacterial surface — the membrane anchoring region. The study found that the loss of this gene significantly reduced both the corrosion rate of the polar marine bacterium and its efficiency in inducing mussel larval settlement: the original villous structure on the bacterial surface disappeared, bacterial adhesion dropped by more than 80%, and consequently the bacterium's colonization on the surface of the low-temperature steel was reduced. In this study, the YadA protein encoded by gene 1308 in the polar marine bacterium acts as a molecular anchor on the bacterial surface, mediating rapid adhesion of the bacterium to the material surface while continuously secreting corrosive extracellular substances and releasing chemical signals that induce the settlement of large fouling organisms.
Therefore, under polar marine environmental conditions, the YadA adhesin is the key factor determining biofilm-mediated biocorrosion and biofouling by the psychrophilic bacterium Psychrobacter cibarius. This study provides new research approaches for the prevention and control of biocorrosion and biofouling in polar marine environments, and lays a theoretical foundation for developing protective materials that precisely target the adhesin and its secretion pathway.
Wang Xiaoyu, a doctoral student at Shanghai Ocean University, is the first author of the paper; Associate Professor Liang Xiao of Shanghai Ocean University and Senior Engineer Guo Na of Shanghai Maritime University are the co-corresponding authors. This research was supported by the National Key R&D Program of China.
Article link:Xiaoyu Wang, Xiaomin Mao, Yuyi Wang, Lihua Peng, Jin-Long Yang, Tao Liu, Deborah M Power, Na Guo*, Xiao Liang*. Polar marine biocorrosion and biofouling processes mediated by the trimeric autotransporter adhesin of Psychrobacter cibarius [J]. Corrosion Science, 2026, 272: 114183. https://doi.org/10.1016/j.corsci.2026.114183