Type<scp>VI</scp>secretion system effector proteins: Effective weapons for bacterial competitiveness

Hernandez, Ruth E.; Gallegos‐Monterrosa, Ramses; Coulthurst, Sarah J.

doi:10.1111/cmi.13241

Cited by 114 publications

(112 citation statements)

References 58 publications

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“…SsdAI is an exclusively a-helical protein that shares a large (~1300 Å 2 ) interface with SsdA. As is often observed in toxin-immunity co-crystal structures, this interface effectively demarcates the active site of SsdA ( Figure 6A) (13). Much of the SsdA-interacting surface of SsdAI is composed of a protrusion that includes an extended loop and two short helical segments that project residues into the active site cavity of SsdA ( Figure 6F).…”

Section: The Ssda Structure Specifies a New Group Of Bacterial Deaminmentioning

confidence: 82%

“…Beyond these outcomes that are detrimental to recipient cells, there are also scenarios in which toxin delivery could provide a transient benefit. Within populations of toxin producing strains, self-intoxication is prevented through the production of specific immunity determinants that neutralize individual toxins (13). Toxins inactivated by immunity proteins in this manner are generally assumed to have no or little impact.…”

Section: Introductionmentioning

confidence: 99%

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An interbacterial DNA deaminase toxin directly mutagenizes surviving target populations

Moraes

Hsü

Huang

et al. 2020

Preprint

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When bacterial cells come in contact, antagonism mediated by the delivery of toxins frequently ensues. The potential for such encounters to have long-term beneficial consequences in recipient cells has not been investigated. Here we examined the effects of intoxication by DddA, a cytosine deaminase delivered via the type VI secretion system (T6SS) of Burkholderia cenocepacia. Despite its killing potential, we observed that several bacterial species resist DddA and instead accumulate mutations installed by the toxin, indicating that even in the absence of killing, interbacterial toxins can have profound consequences on target populations. Investigation of additional toxins from the deaminase superfamily revealed that mutagenic activity is a common feature of these proteins, including a representative we show targets single-stranded DNA and displays a markedly divergent structure. Our findings suggest that a surprising consequence of antagonistic interactions between bacteria could be the promotion of adaptation via the action of directly mutagenic toxins.

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Section: The Ssda Structure Specifies a New Group Of Bacterial Deaminmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

An interbacterial DNA deaminase toxin directly mutagenizes surviving target populations

Moraes

Hsü

Huang

et al. 2020

Preprint

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“…T6SS is a versatile machinery playing roles in both pathogenesis and interbacterial competition by translocating T6SS effectors. T6SS effectors are loaded into the inner tube or associate with the spike trimer during T6SS assembly (Silverman et al, 2013;Flaugnatti et al, 2016;Hernandez et al, 2020). Contraction of the sheath propels the inner tube/spike, which allows perforation of the target cell membrane, delivering effectors into the cytosol of target cells (Journet and Cascales, 2016).…”

Section: Discussionmentioning

confidence: 99%

“…Besides the core apparatus protein, EvpP (T6SS effector protein), EvpC (a homolog of Hcp), and EvpI (a homolog of VgrG) are three secreted proteins encoded inside the T6SS gene cluster (Zheng and Leung, 2007). T6SS is a contractile injection apparatus that translocates a tail tube and a spike loaded with various effectors directly into eukaryotic or prokaryotic target cells (Silverman et al, 2013;Flaugnatti et al, 2016;Hernandez et al, 2020;Wettstadt and Filloux, 2020). The T6SS spike punctures the bacterial cell envelope allowing the transport of effectors, and it consists of a torch-like VgrG trimer (encoded by evpI in E. piscicida) on which sits a PAAR protein sharpening the VgrG tip (encoded by evpJ in E. piscicida), and VgrG itself sits on the Hcp tube (encoded by evpC in E. piscicida).…”

Section: Introductionmentioning

confidence: 99%

Identification and Characterization of EvpQ, a Novel T6SS Effector Encoded on a Mobile Genetic Element in Edwardsiella piscicida

Liu²,

Liao³

et al. 2021

Front. Microbiol.

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In this study, a hypothetical protein (ORF02740) secreted by Edwardsiella piscicida was identified. We renamed the ORF02740 protein as EvpQ, which is encoded by a mobile genetic element (MGE) in E. piscicida genome. The evpQ gene is spaced by 513 genes from type VI secretion system (T6SS) gene cluster. Low GC content, three tRNA, and three transposase genes nearby evpQ define this MGE that evpQ localizes as a genomic island. Sequence analysis reveals that EvpQ shares a conserved domain of C70 family cysteine protease and shares 23.91% identity with T3SS effector AvrRpt2 of phytopathogenic Erwinia amylovora. Instead, EvpQ of E. piscicida is proved to be secreted at a T6SS-dependent manner, and it can be translocated into host cells. EvpQ is thereof a novel T6SS effector. Significantly decreased competitive index of ΔevpQ strain in blue gourami fish (0.53 ± 0.27 in head kidney and 0.44 ± 0.19 in spleen) indicates that EvpQ contributes to the pathogenesis of E. piscicida. At 8-, 18-, and 24-h post-subculture into DMEM, the transcription of evpQ was found to be negatively regulated by Fur and positively regulated by EsrC, and the steady-state protein levels of EvpQ are negatively controlled by RpoS. Our study lays a foundation for further understanding the pathogenic role of T6SS in edwardsiellosis.

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“…Most T6SS effectors have anti‐bacterial activity and have been proven quite efficient against other gram‐negative bacteria although anti‐eukaryotic effectors against animal and fungi cells have been also described (Allsopp et al ., 2020). Antimicrobial effectors target nucleic acids (nucleases) or other essential cytoplasmic elements (ADP‐ribosyl transferases (Tre1), glycohydrolases (Tne), and (p)ppApp synthases (Tas1) or disrupt the cell wall (amidases, muramidases) or the cytoplasmic membrane (lipases, pore‐forming bacteriocins) (Hernandez et al ., 2020). The arsenal of T6SS effectors has continued to grow since the first identified T6 effector (Hood et al ., 2010) and nowadays about 10 to 20 has been described for Pseudomonas aeruginosa and Vibrio cholerae .…”

Section: Type VI Secretion Systemmentioning

confidence: 99%

Plant holobiont interactions mediated by the type VI secretion system and the membrane vesicles: promising tools for a greener agriculture

Acuña

Bernal

2021

Environmental Microbiology

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A deeper understanding of the complex relationship between plants and their microbiota is allowing researchers to appreciate a plethora of possibilities to improve crops using chemical-free alternatives based on beneficial microorganisms. An increase in crop yield from the promotion of plant growth or even simultaneous protection of the plants from the attack of phytopathogens can be achieved in the presence of different plant-associated microorganisms known as plant-growthpromoting rhizobacteria (PGPR) and biocontrol agents (BCAs), respectively. Thus, the study of the great diversity of plant-microbe and microbe-microbe interactions is an attention-grabbing topic covering studies of interactions since the plant seed and through all developmental stages, from root to shoot. The intricate communication systems that plant holobionts co-evolved has resulted in many different strategies and interplays between these organisms shaping the bacterial communities and the plant fitness simultaneously. Herein, we emphasize two understudied delivery systems existing in plant-associated bacteria: the type VI secretion system (T6SS) and the membrane vesicles with a huge potential to boost a highly demanded and necessary green agriculture.

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TypeVIsecretion system effector proteins: Effective weapons for bacterial competitiveness

Cited by 114 publications

References 58 publications

An interbacterial DNA deaminase toxin directly mutagenizes surviving target populations

An interbacterial DNA deaminase toxin directly mutagenizes surviving target populations

Identification and Characterization of EvpQ, a Novel T6SS Effector Encoded on a Mobile Genetic Element in Edwardsiella piscicida

Plant holobiont interactions mediated by the type VI secretion system and the membrane vesicles: promising tools for a greener agriculture

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