PUBLICATION

Identification of a new effector-immunity pair of Aeromonas hydrophila type VI secretion system

Authors
Ma, S., Dong, Y., Wang, N., Liu, J., Lu, C., Liu, Y.
ID
ZDB-PUB-200526-12
Date
2020
Source
Veterinary research   51: 71 (Journal)
Registered Authors
Keywords
none
MeSH Terms
  • Aeromonas hydrophila/genetics
  • Aeromonas hydrophila/pathogenicity
  • Aeromonas hydrophila/physiology*
  • Animals
  • Bacterial Proteins/immunology*
  • Biofilms
  • Fish Diseases/immunology*
  • Fish Diseases/microbiology
  • Genes, Bacterial/immunology*
  • Gram-Negative Bacterial Infections/immunology
  • Gram-Negative Bacterial Infections/microbiology
  • Gram-Negative Bacterial Infections/veterinary*
  • Microbial Interactions
  • Type VI Secretion Systems/immunology*
  • Virulence
  • Zebrafish*
PubMed
32448355 Full text @ Vet. Res.
Abstract
The type VI secretion system (T6SS) is a multiprotein weapon that kills eukaryotic predators or prokaryotic competitors by delivering toxic effectors. Despite the importance of T6SS in bacterial environmental adaptation, it is still challenging to systematically identify T6SS effectors because of their high diversity and lack of conserved domains. In this report, we discovered a putative effector gene, U876-17730, in the whole genome of Aeromonas hydrophila NJ-35 based on the reported conservative domain DUF4123 (domain of unknown function), with two cognate immunity proteins encoded downstream. Phylogenetic tree analysis of amino acids indicates that AH17730 belongs to the Tle1 (type VI lipase effector) family, and therefore was named Tle1AH. The deletion of tle1AH resulted in significantly decreased biofilm formation, antibacterial competition ability and virulence in zebrafish (Danio rerio) when compared to the wild-type strain. Only when the two immunity proteins coexist can bacteria protect themselves from the toxicity of Tle1AH. Further study shows that Tle1AH is a kind of phospholipase that possesses a conserved lipase motif, Gly-X-Ser-X-Gly (X is for any amino acid). Tle1AH is secreted by T6SS, and this secretion requires its interaction with an associated VgrG (valine-glycine repeat protein G). In conclusion, we identified a T6SS effector-immunity pair and verified its function, which lays the foundation for future research on the role of T6SS in the pathogenic mechanism of A. hydrophila.
Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping