Abstract
Paradox (Juglans hindsii × J. regia), the dominant rootstock used in California, USA walnut production, has many desirable horticultural characteristics, but is highly susceptible to crown gall. Crown gall, caused by the bacterium Agrobacterium tumefaciens, is not consistently controlled with soil fumigation. This observation, in conjunction with observations of galls occurring in above ground grafting wounds, led to the hypothesis that A. tumefaciens inoculum may be endophytic in walnut seedlings. Paradox seeds collected directly from commercial Paradox mother trees (i.e., Juglans hindsii) were free of A. tumefaciens. Sampling conducted at multiple times during seed production revealed that seed-borne A. tumefaciens populations increased as a function of contact time with the orchard floor. In greenhouse experiments, seeds inoculated with A. tumefaciens produce seedlings with galls at the crown and/or roots in the absence of artificial wounding. Endophytic populations of A. tumefaciens were also found in shoot and root tissue. These data suggest that A. tumefaciens inoculum may exist as a resident endophyte and that timely seed collection, limiting contact with the orchard floor, may be an important first step in preventing crown gall disease of walnut.
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Claims 6
Claim · model-written summary
Seed-borne A. tumefaciens populations increased with contact time with the orchard floor during seed production.
- Taxon
- Paradox (Juglans hindsii × J. regia)
Juglans hindsiie2 - Treatment
- contact time with the orchard floore1
- Interactor
- A. tumefaciens
Agrobacterium tumefaciense1pathogen - Outcome
- seed-borne A. tumefaciens populationse1
- Direction
- increasede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Sampling conducted at multiple times during seed production revealed that seed-borne A. tumefaciens populations increased as a function of contact time with the orchard floor”
e2“Paradox (Juglans hindsii × J. regia)”
Claim · model-written summary
Paradox seeds collected from commercial mother trees were free of A. tumefaciens.
- Taxon
- Paradox (Juglans hindsii × J. regia)Juglans hindsiie2
- Organ / stage
- seedse1
- Interactor
- A. tumefaciensAgrobacterium tumefaciense1pathogen
- Outcome
- free of A. tumefaciense1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Paradox seeds collected directly from commercial Paradox mother trees (i.e., Juglans hindsii) were free of A. tumefaciens”
e2“Paradox (Juglans hindsii × J. regia)”
Claim · model-written summary
Seeds inoculated with A. tumefaciens produced seedlings with galls at the crown and/or roots in greenhouse experiments without artificial wounding.
- Taxon
- Paradox (Juglans hindsii × J. regia)Juglans hindsiie2
- Treatment
- seeds inoculated with A. tumefaciense1
- Interactor
- A. tumefaciensAgrobacterium tumefaciense1pathogen
- Outcome
- galls at the crown and/or rootse1
- Qualifier
- in the absence of artificial woundinge1
- Setting
- greenhouse experimentse1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In greenhouse experiments, seeds inoculated with A. tumefaciens produce seedlings with galls at the crown and/or roots in the absence of artificial wounding”
e2“Paradox (Juglans hindsii × J. regia)”
Claim · model-written summary
Endophytic A. tumefaciens populations were found in shoot and root tissue.
- Taxon
- Paradox (Juglans hindsii × J. regia)Juglans hindsiie2
- Organ / stage
- shoot and root tissuee1
- Interactor
- A. tumefaciensAgrobacterium tumefaciense1pathogen
- Outcome
- Endophytic populations of A. tumefaciense1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Endophytic populations of A. tumefaciens were also found in shoot and root tissue”
e2“Paradox (Juglans hindsii × J. regia)”
Claim · model-written summary
A. tumefaciens inoculum may exist as a resident endophyte in walnut seedlings.
- Taxon
- Paradox (Juglans hindsii × J. regia)Juglans hindsiie2
- Interactor
- A. tumefaciensAgrobacterium tumefaciense1pathogen
- Outcome
- resident endophytee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“These data suggest that A. tumefaciens inoculum may exist as a resident endophyte”
e2“Paradox (Juglans hindsii × J. regia)”
Claim · model-written summary
Timely seed collection and limiting seed contact with the orchard floor may be an important first step in preventing crown gall disease of walnut.
Verbatim
e1“timely seed collection, limiting contact with the orchard floor, may be an important first step in preventing crown gall disease of walnut”
The same questions in other papers
Agrobacterium tumefaciens · pest · Juglans hindsiiResults agree
1 paper in the same direction as this paper
- negative
inoculation · pest · Juglans hindsiiResults agree
1 paper in the same direction as this paper
- negative
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.