Xanthomonas citri T6SS mediates resistance to Dictyostelium predation and is regulated by an ECF &sgr; factor and cognate Ser/Thr kinase

@article{BayerSantos2018XanthomonasCT,
  title={Xanthomonas citri T6SS mediates resistance to Dictyostelium predation and is regulated by an ECF \&sgr; factor and cognate Ser/Thr kinase},
  author={Ethel Bayer-Santos and L{\'i}dia Dos Passos Lima and Lucas de Moraes Ceseti and Camila Yuri Ratagami and Eliane Silva de Santana and Aline Maria da Silva and Chuck Shaker Farah and Cristina Elisa Alvarez-Martinez},
  journal={Environmental Microbiology},
  year={2018},
  volume={20},
  pages={1562–1575}
}
Plant-associated bacteria of the genus Xanthomonas cause disease in a wide range of economically important crops. However, their ability to persist in the environment is still poorly understood. Predation by amoebas represents a major selective pressure to bacterial populations in the environment. In this study, we show that the X. citri type 6 secretion system (T6SS) promotes resistance to predation by the soil amoeba Dictyostelium discoideum. We found that an extracytoplasmic function (ECF… 

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References

SHOWING 1-10 OF 69 REFERENCES

A TonB-dependent transducer is responsible for regulation of pathogenicity-related genes in Xanthomonas axonopodis pv. citri

The results suggest that XAC4131 controls the expression of hrpG indirectly, probably via rpoEXAC4129 and XAC4130 and seems to be regulated by the Fur protein.

Regulation of Type VI Secretion Gene Clusters by σ54 and Cognate Enhancer Binding Proteins

Using in vitro binding experiments and in vivo reporter fusion assays, it is shown that the expression of several T6SS gene clusters is dependent on both σ(54) and bEBPs, which are found in the genomes of most species of gram-negative bacteria.

Vibrio cholerae Requires the Type VI Secretion System Virulence Factor VasX To Kill Dictyostelium discoideum

Evidence is presented that VasH regulates the production of a newly identified protein, VasX, which in turn requires a functional T6SS for secretion, and as a V. cholerae mutant lacking vasX exhibits a phenotype of attenuated virulence toward Dictyostelium discoideum.

A Novel Sensor Kinase-Response Regulator Hybrid Controls Biofilm Formation and Type VI Secretion System Activity in Burkholderia cenocepacia

Data show that AtsR is involved in the regulation of genes required for virulence in B. cenocepacia K56-2, including genes encoding a T6SS, which is required for infection in vivo.

Structure-Function Analysis of the HrpB2-HrcU Interaction in the Xanthomonas citri Type III Secretion System

It is shown that the highly conserved HrpB2 C-terminus is essential for T3SS-dependent development of citrus canker symptoms in planta and that an intact and cleavable NPTH site in HrcU is necessary for total functionally of T3 SS in X. citri.

Burkholderia Type VI Secretion Systems Have Distinct Roles in Eukaryotic and Bacterial Cell Interactions

The data show that T6SSs within a single organism can have distinct functions in eukaryotic versus bacterial cell interactions, and are likely to be a decisive factor in the survival of bacterial cells of one species in intimate association with those of another, such as in polymicrobial communities present both in the environment and in many infections.

Genetic Analysis of Anti-Amoebae and Anti-Bacterial Activities of the Type VI Secretion System in Vibrio cholerae

This study systematically mutagenized each individual gene in T6SS locus and characterized their functions based on expression and secretion of the hemolysin co-regulated protein, virulence towards amoebae of Dictyostelium discoideum and killing of Escherichia coli bacterial cells.

Bacteria causing important diseases of citrus utilise distinct modes of pathogenesis to attack a common host

The current knowledge on three pathogens that exhibit distinct tissue specificity and modes of pathogenesis in citrus plants are summarized.

Analysis of the Streptomyces coelicolor sigE gene reveals the existence of a subfamily of eubacterial RNA polymerase sigma factors involved in the regulation of extracytoplasmic functions.

The predicted sequence of sigma E shows greatest similarity to sequences of seven other proteins that define a subfamily of eubacterial RNA polymerase factors sufficiently different from other sigma s that, in many cases, they are not identified by standard similarity searching methods.

Identification of T6SS-dependent effector and immunity proteins by Tn-seq in Vibrio cholerae

A high-throughput approach using transposon mutagenesis and deep sequencing (Tn-seq) to identify T6SS immunity proteins in Vibrio cholerae shows these are important for not only antibacterial and antieukaryotic activities but also assembly of T 6SS apparatus.
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