Abstract
Bacterial type III secretion systems deliver protein virulence factors to host cells. Here we characterize the interaction between HrpB2, a small protein secreted by the Xanthomonas citri subsp. citri type III secretion system, and the cytosolic domain of the inner membrane protein HrcU, a paralog of the flagellar protein FlhB. We show that a recombinant fragment corresponding to the C-terminal cytosolic domain of HrcU produced in E. coli suffers cleavage within a conserved Asn264-Pro265-Thr266-His267 (NPTH) sequence. A recombinant HrcU cytosolic domain with N264A, P265A, T266A mutations at the cleavage site (HrcU(AAAH)) was not cleaved and interacted with HrpB2. Furthermore, a polypeptide corresponding to the sequence following the NPTH cleavage site also interacted with HrpB2 indicating that the site for interaction is located after the NPTH site. Non-polar deletion mutants of the hrcU and hrpB2 genes resulted in a total loss of pathogenicity in susceptible citrus plants and disease symptoms could be recovered by expression of HrpB2 and HrcU from extrachromossomal plasmids. Complementation of the ΔhrcU mutant with HrcU(AAAH) produced canker lesions similar to those observed when complemented with wild-type HrcU. HrpB2 secretion however, was significantly reduced in the ΔhrcU mutant complemented with HrcU(AAAH,) suggesting that an intact and cleavable NPTH site in HrcU is necessary for total functionally of T3SS in X. citri subsp. citri. Complementation of the ΔhrpB2 X. citri subsp. citri strain with a series of hrpB2 gene mutants revealed that the highly conserved HrpB2 C-terminus is essential for T3SS-dependent development of citrus canker symptoms in planta.
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Claims 5
Claim · model-written summary
Deletion of hrcU and hrpB2 abolished pathogenicity in susceptible citrus.
- Treatment
- Non-polar deletion mutantse0
- Interactor
- Xanthomonas citri
Xanthomonas citrit0pathogen - Gene
- hrcU and hrpB2e0
- Outcome
- pathogenicity in susceptible citrus plantse0
- Direction
- total losse0
CitrusNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Non-polar deletion mutants of the hrcU and hrpB2 genes resulted in a total loss of pathogenicity in susceptible citrus plants and disease symptoms could be recovered by expression of HrpB2 and HrcU from extrachromossomal plasmids.”
t0“Xanthomonas citri”
Claim · model-written summary
Plasmid expression of HrpB2 and HrcU recovered citrus disease symptoms.
- Treatment
- expression of HrpB2 and HrcU from extrachromossomal plasmidse0
- Interactor
- Xanthomonas citriXanthomonas citrit0pathogen
- Gene
- HrpB2 and HrcUe0
- Outcome
- disease symptomse0
- Direction
- recoverede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Non-polar deletion mutants of the hrcU and hrpB2 genes resulted in a total loss of pathogenicity in susceptible citrus plants and disease symptoms could be recovered by expression of HrpB2 and HrcU from extrachromossomal plasmids.”
t0“Xanthomonas citri”
Claim · model-written summary
HrcU(AAAH) complementation produced canker lesions similar to wild-type HrcU complementation.
- Treatment
- Complementation of the ΔhrcU mutant with HrcU(AAAH)e0
- Interactor
- Xanthomonas citriXanthomonas citrit0pathogen
- Gene
- HrcU(AAAH)e0
- Outcome
- canker lesionse0
- Direction
- similare0
- Comparator
- wild-type HrcUe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Complementation of the ΔhrcU mutant with HrcU(AAAH) produced canker lesions similar to those observed when complemented with wild-type HrcU.”
t0“Xanthomonas citri”
e1“Non-polar deletion mutants of the hrcU and hrpB2 genes resulted in a total loss of pathogenicity in susceptible citrus plants and disease symptoms could be recovered by expression of HrpB2 and HrcU from extrachromossomal plasmids.”
Claim · model-written summary
HrpB2 secretion was significantly reduced with HrcU(AAAH) complementation.
- Treatment
- complemented with HrcU(AAAH,)e0
- Interactor
- Xanthomonas citriXanthomonas citrit0pathogen
- Gene
- HrpB2e0
- Outcome
- HrpB2 secretione0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“HrpB2 secretion however, was significantly reduced in the ΔhrcU mutant complemented with HrcU(AAAH,)”
t0“Xanthomonas citri”
e1“Non-polar deletion mutants of the hrcU and hrpB2 genes resulted in a total loss of pathogenicity in susceptible citrus plants and disease symptoms could be recovered by expression of HrpB2 and HrcU from extrachromossomal plasmids.”
Claim · model-written summary
The conserved HrpB2 C-terminus was essential for citrus canker symptom development.
- Interactor
- X. citri subsp. citriXanthomonas citri pv. citrie0pathogen
- Gene
- HrpB2 C-terminuse0
- Outcome
- development of citrus canker symptomse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Complementation of the ΔhrpB2 X. citri subsp. citri strain with a series of hrpB2 gene mutants revealed that the highly conserved HrpB2 C-terminus is essential for T3SS-dependent development of citrus canker symptoms in planta.”
The same questions in other papers
transgenic · Xanthomonas citri · CitrusPositive and negative results
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- positive
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loss of function · Xanthomonas citri · CitrusPositive and negative results
1 paper in the same direction as this paper · 2 in the opposite direction
- positive
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Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.