Glucose promotes bacterial fitness while simultaneously repressing a major virulence effector ppTse6
- 1Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University
- 2Fujian Key Laboratory of Special Aquatic Formula Feed, Fujian Tianma Science and Technology Group Co., Ltd
- 3Central Laboratory, Zhongshan Hospital (Xiamen), Fudan University
Abstract
Background Pseudomonas plecoglossicida (P. plecoglossicida) is an important aquatic pathogen whose virulence is closely associated with the type VI secretion system effector ppTse6. Previous studies have demonstrated that ppTse6 disrupts host energy metabolism and contributes substantially to bacterial pathogenicity. However, how environmental nutritional signals regulate ppTse6 expression and influence bacterial adaptation remains poorly understood. This study aimed to determine the role of glucose in regulating ppTse6 expression and glucose-associated physiological traits in P. plecoglossicida. Results P. plecoglossicida was cultured in minimal salt medium supplemented with 5 mM serine and increasing concentrations of glucose. Phenotypic assays, transcriptomic analysis, quantitative real-time PCR and promoter activity assays were performed to investigate glucose-mediated regulation. Glucose promoted bacterial growth, adhesion, and biofilm formation, with the strongest effects observed at 50 mM. Transcriptomic analysis revealed broad changes in genes associated with secretion systems, flagellar assembly, chemotaxis, biofilm formation, and metabolism. Glucose reduced ppTse6 promoter activity and transcript abundance. Deletion of ppTse6 impaired growth, adhesion, chemotaxis toward host mucus, and biofilm formation under glucose-supplemented conditions, whereas basal swimming motility was unaffected. Conclusions This study identifies ppTse6 as a glucose-responsive T6SS effector that is transcriptionally repressed by glucose while contributing to bacterial adaptation under glucose-rich conditions. These findings reveal a previously unrecognized connection between carbon availability and T6SS effector regulation, providing new insights into how nutrient availability shapes bacterial fitness and pathogenic potential in P. plecoglossicida.
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BibTeX
@article{mao2026glucose,
title = {{Glucose promotes bacterial fitness while simultaneously repressing a major virulence effector ppTse6}},
author = {Yuxin Mao and Qingpi Yan and Xizhi Peng and Bing Hu and Jiaonan Zhang and Yujia Sun and Mengting Luo},
journal = {Annals of Microbiology},
year = {2026},
month = sep,
doi = {10.1186/s13213-026-01877-3},
url = {https://doi.org/10.1186/s13213-026-01877-3},
note = {CC BY},
}
RIS
TY - JOUR
TI - Glucose promotes bacterial fitness while simultaneously repressing a major virulence effector ppTse6
AU - Yuxin Mao
AU - Qingpi Yan
AU - Xizhi Peng
AU - Bing Hu
AU - Jiaonan Zhang
AU - Yujia Sun
AU - Mengting Luo
PY - 2026
DA - 2026/09/01
JO - Annals of Microbiology
DO - 10.1186/s13213-026-01877-3
UR - https://doi.org/10.1186/s13213-026-01877-3
AB - Background Pseudomonas plecoglossicida (P. plecoglossicida) is an important aquatic pathogen whose virulence is closely associated with the type VI secretion system effector ppTse6. Previous studies have demonstrated that ppTse6 disrupts host energy metabolism and contributes substantially to bacterial pathogenicity. However, how environmental nutritional signals regulate ppTse6 expression and influence bacterial adaptation remains poorly understood. This study aimed to determine the role of glucose in regulating ppTse6 expression and glucose-associated physiological traits in P. plecoglossicida. Results P. plecoglossicida was cultured in minimal salt medium supplemented with 5 mM serine and increasing concentrations of glucose. Phenotypic assays, transcriptomic analysis, quantitative real-time PCR and promoter activity assays were performed to investigate glucose-mediated regulation. Glucose promoted bacterial growth, adhesion, and biofilm formation, with the strongest effects observed at 50 mM. Transcriptomic analysis revealed broad changes in genes associated with secretion systems, flagellar assembly, chemotaxis, biofilm formation, and metabolism. Glucose reduced ppTse6 promoter activity and transcript abundance. Deletion of ppTse6 impaired growth, adhesion, chemotaxis toward host mucus, and biofilm formation under glucose-supplemented conditions, whereas basal swimming motility was unaffected. Conclusions This study identifies ppTse6 as a glucose-responsive T6SS effector that is transcriptionally repressed by glucose while contributing to bacterial adaptation under glucose-rich conditions. These findings reveal a previously unrecognized connection between carbon availability and T6SS effector regulation, providing new insights into how nutrient availability shapes bacterial fitness and pathogenic potential in P. plecoglossicida.
SN - 1869-2044
SN - 1590-4261
ER -