Abstract
Huanglongbing (HLB) is a destructive disease of citrus in most citrus-producing countries worldwide. The disease, presumably caused by phloem-limited bacteria of the genus Candidatus Liberibacter, affects all known citrus species and citrus relatives with little known resistance. Typical disease symptoms are the production of abnormal-looking fruit and chlorosis or blotchy mottle of the leaves followed at advanced stages by tree decline and death. Trifoliate orange ( P. trifoliata L. Raf.) and some of its hybrids reportedly lack distinct disease symptoms despite infection with the pathogen. US-897 is a hybrid of trifoliate orange and ‘Cleopatra’ mandarin ( C. reticulata Blanco), the latter being highly susceptible to HLB. This study investigated whether field-grown, naturally infected trees and greenhouse-grown, graft-inoculated seedlings of this genotype display tolerance or resistance to HLB. It was shown that naturally infected US-897 trees exhibited no distinct disease symptoms commonly associated with HLB, except for the occurrence of few mottled leaves in a small percentage of trees. Analysis of fruit and seed from infected trees did not detect any growth reduction or otherwise negative impact on development. Graft-inoculated US-897 seedlings became polymerase chain reaction (PCR)-positive for the pathogen but exhibited a superior performance compared with ‘Cleopatra’ mandarin seedlings, which displayed severe disease symptoms soon after inoculation. Despite infection, most US-897 seedlings did not develop leaf symptoms typical for HLB. Foliar symptoms observed in a small number of plants at later stages of the disease were faint and difficult to discern. Contrary to ‘Cleopatra’ seedlings, growth in stem diameter was only moderately reduced or unaffected in infected US-897 seedlings. The superior performance of US-897 plants in greenhouse and field locations suggest tolerance of this genotype to Ca . L. asiaticus.
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Claims 7
Claim · model-written summary
Naturally infected US-897 trees in the field showed no distinct HLB disease symptoms, except few mottled leaves in a small percentage of trees.
- Material
- US-897e1
- Outcome
- disease symptoms commonly associated with HLBe1
- Qualifier
- except for the occurrence of few mottled leaves in a small percentage of treese1
- Setting
- field-growne0
CitrusOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Tolerance of the Trifoliate Citrus Hybrid US-897 (Citrus reticulata Blanco × Poncirus trifoliata L. Raf.) to Huanglongbing”
e0“field-grown, naturally infected trees and greenhouse-grown, graft-inoculated seedlings”
e1“It was shown that naturally infected US-897 trees exhibited no distinct disease symptoms commonly associated with HLB, except for the occurrence of few mottled leaves in a small percentage of trees”
Claim · model-written summary
Fruit and seed from infected US-897 trees showed no growth reduction or other negative impact on development.
- Outcome
- growth reduction or otherwise negative impact on developmente2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Tolerance of the Trifoliate Citrus Hybrid US-897 (Citrus reticulata Blanco × Poncirus trifoliata L. Raf.) to Huanglongbing”
e2“Analysis of fruit and seed from infected trees did not detect any growth reduction or otherwise negative impact on development”
Claim · model-written summary
Graft-inoculated US-897 seedlings became PCR-positive for Candidatus Liberibacter.
- Material
- US-897e3
- Interactor
- Candidatus LiberibacterLiberibactere0pathogen
- Outcome
- polymerase chain reaction (PCR)-positivee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Tolerance of the Trifoliate Citrus Hybrid US-897 (Citrus reticulata Blanco × Poncirus trifoliata L. Raf.) to Huanglongbing”
e0“presumably caused by phloem-limited bacteria of the genus Candidatus Liberibacter”
e3“Graft-inoculated US-897 seedlings became polymerase chain reaction (PCR)-positive for the pathogen but exhibited a superior performance compared with ‘Cleopatra’ mandarin seedlings, which displayed severe disease symptoms soon after inoculation”
Claim · model-written summary
Graft-inoculated US-897 seedlings performed superior to ‘Cleopatra’ mandarin seedlings, which displayed severe disease symptoms after inoculation.
- Material
- US-897e3
- Treatment
- Graft-inoculatede3
- Interactor
- Candidatus LiberibacterLiberibactere0pathogen
- Outcome
- performancee3
- Direction
- superiore3
- Comparator
- ‘Cleopatra’ mandarin seedlingse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Tolerance of the Trifoliate Citrus Hybrid US-897 (Citrus reticulata Blanco × Poncirus trifoliata L. Raf.) to Huanglongbing”
e0“presumably caused by phloem-limited bacteria of the genus Candidatus Liberibacter”
e3“Graft-inoculated US-897 seedlings became polymerase chain reaction (PCR)-positive for the pathogen but exhibited a superior performance compared with ‘Cleopatra’ mandarin seedlings, which displayed severe disease symptoms soon after inoculation”
Claim · model-written summary
Most graft-inoculated US-897 seedlings did not develop leaf symptoms typical for HLB; the few foliar symptoms were faint.
- Material
- US-897e4
- Outcome
- leaf symptoms typical for HLBe4
- Qualifier
- Foliar symptoms observed in a small number of plants at later stages of the disease were faint and difficult to discerne4
- Setting
- greenhouse-growne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Tolerance of the Trifoliate Citrus Hybrid US-897 (Citrus reticulata Blanco × Poncirus trifoliata L. Raf.) to Huanglongbing”
e0“field-grown, naturally infected trees and greenhouse-grown, graft-inoculated seedlings”
e4“Despite infection, most US-897 seedlings did not develop leaf symptoms typical for HLB. Foliar symptoms observed in a small number of plants at later stages of the disease were faint and difficult to discern”
Claim · model-written summary
Stem diameter growth in infected US-897 seedlings was only moderately reduced or unaffected, unlike ‘Cleopatra’ seedlings.
- Treatment
- infected US-897 seedlingse5
- Outcome
- growth in stem diametere5
- Direction
- only moderately reduced or unaffectede5
- Comparator
- ‘Cleopatra’ seedlingse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Tolerance of the Trifoliate Citrus Hybrid US-897 (Citrus reticulata Blanco × Poncirus trifoliata L. Raf.) to Huanglongbing”
e5“Contrary to ‘Cleopatra’ seedlings, growth in stem diameter was only moderately reduced or unaffected in infected US-897 seedlings”
Claim · model-written summary
The superior performance of US-897 plants in greenhouse and field locations suggests tolerance of this genotype to Ca. L. asiaticus.
- Material
- US-897e6
- Interactor
- Ca . L. asiaticuse6pathogen
- Outcome
- tolerance of this genotypee6
- Setting
- greenhouse and field locationse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Tolerance of the Trifoliate Citrus Hybrid US-897 (Citrus reticulata Blanco × Poncirus trifoliata L. Raf.) to Huanglongbing”
e6“The superior performance of US-897 plants in greenhouse and field locations suggest tolerance of this genotype to Ca . L. asiaticus”
The same questions in other papers
infection · growth · CitrusPositive and negative results
1 paper in the same direction as this paper · 7 in the opposite direction
- negative
- negative
- negative
5 papers more in this group
See all 9 papers →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.