CdgH-mediated c-di-GMP signaling orchestrates biofilm development through VpsT paralogues and VpsR in Vibrio alginolyticus.
7 affiliations
- 1State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, Hainan Province, 570228, China.
- 2Key Laboratory of Tropical Hydrobiology and Biotechnology of Hainan Province, School of Marine Biology and Fisheries, Hainan University, Haikou, Hainan Province, 570228, China.
- 3Wenchang Advanced Fisheries Research Institute, Hainan University, Wenchang, Hainan Province, 571330, China.
- 4School of Ecology, Hainan University, Haikou, Hainan Province, 570228, China.
- 5State Key Laboratory of Marine Resource Utilization in the South China Sea, Hainan University, Haikou, Hainan Province, 570228, China. [email protected].
- 6Key Laboratory of Tropical Hydrobiology and Biotechnology of Hainan Province, School of Marine Biology and Fisheries, Hainan University, Haikou, Hainan Province, 570228, China. [email protected].
- 7Wenchang Advanced Fisheries Research Institute, Hainan University, Wenchang, Hainan Province, 571330, China. [email protected].
Abstract
Background
Vibrio alginolyticus is an opportunistic pathogen that significantly affects both aquaculture and public health. The second messenger cyclic-di-GMP (c-di-GMP) plays a central role in regulating key bacterial behaviors such as motility, biofilm formation, and secretion systems expression, thereby enhancing environmental persistence and virulence. However, the c-di-GMP regulatory network in V. alginolyticus remains poorly defined, limiting our understanding of its pathogenicity and adaptive strategies.Results
We demonstrate that overexpression of the diguanylate cyclase CdgH increases intracellular c-di-GMP levels, which in turn promotes biofilm formation, rugose colony morphology, and Congo Red binding. RNA-seq and molecular analyses revealed that the extracellular polysaccharide synthesis locus rbr (regulation of biofilm formation and rugose morphology) is essential for the development of c-di-GMP-dependent biofilms and associated rugose colony phenotypes. Across Vibrio species, VpsT-like proteins-most of which contain a conserved c-di-GMP-binding motif, W[F/L/M][T/S]R-are important transcriptional regulators. V. alginolyticus encodes three VpsT-like proteins (VA3545, VA3546, and VA2703). Here, we identified VA3545 (RbrT) and another regulator, VpsR, as key positive regulators of biofilm formation. Genetic and expression analyses indicated that VpsR likely functions downstream of RbrT in the biofilm regulatory pathway, whereas VA3546 (RbrN) and VA2703 (RbrO) exhibited opposing effects. Surface plasmon resonance (SPR) confirmed direct binding of c-di-GMP to both RbrT and VpsR, with the conserved arginine residue within the WLSR motif being essential for RbrT function. Furthermore, elevated c-di-GMP levels suppressed swarming motility by downregulating flagellar synthesis genes. Notably, high c-di-GMP also significantly altered the transcription of several core conserved genes associated with type II and type VI secretion systems (T2SS/T6SS) in V. alginolyticus.Conclusions
These findings suggest distinct roles for VpsT homologs and VpsR in biofilm development and show transcriptional regulation of key secretion system genes by c-di-GMP, offering new insights into the pathogenicity and environmental adaptation of V. alginolyticus.
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BibTeX
@article{gong2026cdghmediated,
title = {{CdgH-mediated c-di-GMP signaling orchestrates biofilm development through VpsT paralogues and VpsR in Vibrio alginolyticus.}},
author = {Xiaoxiao Gong and Yanhua Zeng and Wen Li and Yuxuan Wang and Ning Wang and Na Zhang and Aiyou Huang and Hao Long and Zhenyu Xie},
journal = {BMC microbiology},
year = {2026},
month = jul,
doi = {10.1186/s12866-026-05435-4},
url = {https://europepmc.org/article/MED/42972222},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - CdgH-mediated c-di-GMP signaling orchestrates biofilm development through VpsT paralogues and VpsR in Vibrio alginolyticus.
AU - Xiaoxiao Gong
AU - Yanhua Zeng
AU - Wen Li
AU - Yuxuan Wang
AU - Ning Wang
AU - Na Zhang
AU - Aiyou Huang
AU - Hao Long
AU - Zhenyu Xie
PY - 2026
DA - 2026/07/22
JO - BMC microbiology
DO - 10.1186/s12866-026-05435-4
UR - https://europepmc.org/article/MED/42972222
AB - Background Vibrio alginolyticus is an opportunistic pathogen that significantly affects both aquaculture and public health. The second messenger cyclic-di-GMP (c-di-GMP) plays a central role in regulating key bacterial behaviors such as motility, biofilm formation, and secretion systems expression, thereby enhancing environmental persistence and virulence. However, the c-di-GMP regulatory network in V. alginolyticus remains poorly defined, limiting our understanding of its pathogenicity and adaptive strategies.Results We demonstrate that overexpression of the diguanylate cyclase CdgH increases intracellular c-di-GMP levels, which in turn promotes biofilm formation, rugose colony morphology, and Congo Red binding. RNA-seq and molecular analyses revealed that the extracellular polysaccharide synthesis locus rbr (regulation of biofilm formation and rugose morphology) is essential for the development of c-di-GMP-dependent biofilms and associated rugose colony phenotypes. Across Vibrio species, VpsT-like proteins-most of which contain a conserved c-di-GMP-binding motif, W[F/L/M][T/S]R-are important transcriptional regulators. V. alginolyticus encodes three VpsT-like proteins (VA3545, VA3546, and VA2703). Here, we identified VA3545 (RbrT) and another regulator, VpsR, as key positive regulators of biofilm formation. Genetic and expression analyses indicated that VpsR likely functions downstream of RbrT in the biofilm regulatory pathway, whereas VA3546 (RbrN) and VA2703 (RbrO) exhibited opposing effects. Surface plasmon resonance (SPR) confirmed direct binding of c-di-GMP to both RbrT and VpsR, with the conserved arginine residue within the WLSR motif being essential for RbrT function. Furthermore, elevated c-di-GMP levels suppressed swarming motility by downregulating flagellar synthesis genes. Notably, high c-di-GMP also significantly altered the transcription of several core conserved genes associated with type II and type VI secretion systems (T2SS/T6SS) in V. alginolyticus.Conclusions These findings suggest distinct roles for VpsT homologs and VpsR in biofilm development and show transcriptional regulation of key secretion system genes by c-di-GMP, offering new insights into the pathogenicity and environmental adaptation of V. alginolyticus.
SN - 1471-2180
ER -