Abstract
A locus in Pseudomonas solanacearum AW1 responsible for the hypersensitive response (HR) on tobacco was cloned by complementation in the tobacco-pathogenic strain P. solanacearum NC252. The NC252 HR+ transconjugants lost pathogenicity on tobacco, indicating that the cloned locus could restrict the host range of NC252. Restriction enzyme mapping, transposon mutagenesis, and subcloning showed that, at most, 2.0 kilobases of the cloned DNA was required for NC252 transconjugants to elicit HR on tobacco. Site-directed insertional mutagenesis of the wild-type locus in strain AW1 to create AW1-31 eliminated HR activity on tobacco. However, AW1-31 retained pathogenicity on tomato and eggplant, confirming that this locus contains an avirulence gene, designated avrA. In contrast to the wild type, AW1-31 multiplied to almost the same extent as NC252 after infiltration into tobacco leaves. Nevertheless, AW1-31 did not wilt tobacco when stem inoculated, suggesting that additional factors condition host range. AW1 was HR+ on 27 N. tabacum cultivars, whereas AW1-31 was always HR-, strongly suggesting that avrA is specific at the host species level.
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Claims 11
Claim · model-written summary
Transconjugants with the locus lost tobacco pathogenicity.
- Taxon
- tobacco
Nicotiana tabacume0 - Material
- NC252 HR+ transconjugantse0
- Outcome
- pathogenicity on tobaccoe0
- Direction
- loste0
Not reportedInteractorTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The NC252 HR+ transconjugants lost pathogenicity on tobacco”
Claim · model-written summary
At most 2.0 kb of cloned DNA was needed to elicit tobacco HR.
- Taxon
- tobaccoNicotiana tabacume0
- Material
- NC252 transconjugantse0
- Outcome
- elicit HR on tobaccoe0
- Value
- 2.0 kilobasese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“at most, 2.0 kilobases of the cloned DNA was required for NC252 transconjugants to elicit HR on tobacco.”
Claim · model-written summary
Mutating the wild-type locus eliminated tobacco HR activity.
- Taxon
- tobaccoNicotiana tabacume0
- Material
- AW1-31e0
- Treatment
- Site-directed insertional mutagenesis of the wild-type locuse0
- Outcome
- HR activity on tobaccoe0
- Direction
- eliminatede0
- Comparator
- wild-type locuse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Site-directed insertional mutagenesis of the wild-type locus in strain AW1 to create AW1-31 eliminated HR activity on tobacco.”
Claim · model-written summary
AW1-31 retained pathogenicity on tomato.
- Taxon
- tomato
Solanum lycopersicume0 - Material
- AW1-31e0
- Outcome
- pathogenicity on tomatoe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“AW1-31 retained pathogenicity on tomato and eggplant”
Claim · model-written summary
AW1-31 retained pathogenicity on eggplant.
- Taxon
- eggplant
Solanum melongenae0 - Material
- AW1-31e0
- Outcome
- pathogenicitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“AW1-31 retained pathogenicity on tomato and eggplant”
Claim · model-written summary
The locus contains the avirulence gene avrA.
Not reportedTaxon
Verbatim
e0“this locus contains an avirulence gene, designated avrA.”
Claim · model-written summary
AW1-31 multiplied in tobacco leaves almost as much as NC252.
- Taxon
- tobaccoNicotiana tabacume0
- Material
- AW1-31e0
- Organ / stage
- leavese0
- Outcome
- multipliede0
- Direction
- almost the same extente0
- Comparator
- NC252e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“AW1-31 multiplied to almost the same extent as NC252 after infiltration into tobacco leaves.”
Claim · model-written summary
AW1-31 did not wilt tobacco following stem inoculation.
- Taxon
- tobaccoNicotiana tabacume0
- Material
- AW1-31e0
- Treatment
- stem inoculatede0
- Outcome
- did not wilt tobaccoe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“AW1-31 did not wilt tobacco when stem inoculated”
Claim · model-written summary
AW1 elicited HR in 27 tobacco cultivars.
- Taxon
- N. tabacumNicotiana tabacume0
- Material
- 27 N. tabacum cultivarse0
- Outcome
- HR+e0
- Value
- 27e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“AW1 was HR+ on 27 N. tabacum cultivars”
Claim · model-written summary
AW1-31 was consistently HR-negative on the tobacco cultivars.
Not reportedTaxon
Verbatim
e0“AW1-31 was always HR-”
Claim · model-written summary
avrA appears to act at the host species level.
Not reportedTaxon
Verbatim
e0“strongly suggesting that avrA is specific at the host species level.”