Abstract
A gnotobiotic bioassay, using potato plantlets derived from single-node explants and grown in test tubes containing potato nodal cutting medium (PNCM), was found to be highly useful for investigations of direct growth promotion by a nonfluorescent Pseudomonas sp. strain PsJN. Strain PsJN was used to optimize and evaluate this bioassay for purposes of screening other rhizosphere bacteria and identification of Tn5 mutants of strain PsJN deficient in growth-promoting properties. The selection of potato cultivar used in this bioassay was critical, as growth promotion of potatoes by strain PsJN was cultivar specific. Inoculated plantlets of cultivars Norchip, Kennebec, Shepody, and Chaleur showed, in root dry weight, a five- to eight-fold increase, two- to three-fold increase, no response, and a decrease of 50%, respectively. Haulm dry weight followed similar trends but was not as consistent an indicator of growth promotion. Bioassay results were not altered to any extent by minor changes in PNCM composition or by slight changes in temperature and light conditions. A rapid method for preparation of bacterial suspensions and inoculation of explants was developed. Inoculation of three explants taken from 6-week-old stock plantlets of cv. Kennebec for each Tn5 transconjugate of strain PsJN (total of 1500 transconjugates) enabled the elimination of 93% of those isolates that retained growth-promoting activity. The remaining 7% of isolates were retested and seven were confirmed to have lost growth-promoting ability. Bacteria from different genera were also screened with this bioassay. None of these bacteria increased the growth of potato plantlets, but several inhibited root and haulm growth.Key words: plant growth-promoting rhizobacteria, gnotobiotic, tissue culture, nonfluorescent pseudomonad, bacterium, potato.
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Claims 11
Claim · model-written summary
The gnotobiotic potato bioassay was highly useful for testing growth promotion by PsJN.
- Taxon
- potato
Solanum tuberosume0 - Interactor
- Pseudomonas sp. strain PsJN
Pseudomonas sp.e0other - Outcome
- highly useful for investigations of direct growth promotione0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A gnotobiotic bioassay, using potato plantlets derived from single-node explants and grown in test tubes containing potato nodal cutting medium (PNCM), was found to be highly useful for investigations of direct growth promotion by a nonfluorescent Pseudomonas sp. strain PsJN.”
Claim · model-written summary
PsJN increased root dry weight five- to eight-fold in Norchip.
- Taxon
- potatoesSolanum tuberosume1
- Material
- Norchipe0
- Treatment
- Inoculatede0
- Interactor
- strain PsJNe1other
- Outcome
- root dry weighte0
- Direction
- increasee0
- Value
- five- to eight-folde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculated plantlets of cultivars Norchip, Kennebec, Shepody, and Chaleur showed, in root dry weight, a five- to eight-fold increase, two- to three-fold increase, no response, and a decrease of 50%, respectively.”
e1“growth promotion of potatoes by strain PsJN was cultivar specific”
Claim · model-written summary
PsJN increased root dry weight two- to three-fold in Kennebec.
- Taxon
- potatoesSolanum tuberosume1
- Material
- Kennebece0
- Treatment
- Inoculatede0
- Interactor
- strain PsJNe1other
- Outcome
- root dry weighte0
- Direction
- increasee0
- Value
- two- to three-folde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculated plantlets of cultivars Norchip, Kennebec, Shepody, and Chaleur showed, in root dry weight, a five- to eight-fold increase, two- to three-fold increase, no response, and a decrease of 50%, respectively.”
e1“growth promotion of potatoes by strain PsJN was cultivar specific”
Claim · model-written summary
Shepody root dry weight did not respond to PsJN inoculation.
- Taxon
- potatoesSolanum tuberosume1
- Material
- Shepodye0
- Treatment
- Inoculatede0
- Interactor
- strain PsJNe1other
- Outcome
- root dry weighte0
- Direction
- no responsee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculated plantlets of cultivars Norchip, Kennebec, Shepody, and Chaleur showed, in root dry weight, a five- to eight-fold increase, two- to three-fold increase, no response, and a decrease of 50%, respectively.”
e1“growth promotion of potatoes by strain PsJN was cultivar specific”
Claim · model-written summary
PsJN reduced Chaleur root dry weight by 50%.
- Taxon
- potatoesSolanum tuberosume1
- Material
- Chaleure0
- Treatment
- Inoculatede0
- Interactor
- strain PsJNe1other
- Outcome
- root dry weighte0
- Direction
- decreasee0
- Value
- 50%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculated plantlets of cultivars Norchip, Kennebec, Shepody, and Chaleur showed, in root dry weight, a five- to eight-fold increase, two- to three-fold increase, no response, and a decrease of 50%, respectively.”
e1“growth promotion of potatoes by strain PsJN was cultivar specific”
Claim · model-written summary
Haulm dry weight followed root trends but was less consistent as an indicator.
- Taxon
- potatoesSolanum tuberosumt0
- Outcome
- Haulm dry weighte0
- Comparator
- growth promotione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Haulm dry weight followed similar trends but was not as consistent an indicator of growth promotion.”
t0“potatoes”
Claim · model-written summary
Minor medium, temperature and light changes did not materially change bioassay results.
- Taxon
- potatoesSolanum tuberosumt0
- Outcome
- Bioassay resultse0
- Direction
- not alterede0
- Comparator
- minor changes in PNCM compositione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Bioassay results were not altered to any extent by minor changes in PNCM composition or by slight changes in temperature and light conditions.”
t0“potatoes”
Claim · model-written summary
Screening eliminated 93% of transconjugates retaining growth-promotion activity.
- Taxon
- potatoesSolanum tuberosumt0
- Outcome
- eliminatione0
- Value
- 93%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“enabled the elimination of 93% of those isolates that retained growth-promoting activity”
t0“potatoes”
Claim · model-written summary
Seven retested isolates were confirmed to have lost growth-promoting ability.
- Taxon
- potatoesSolanum tuberosumt0
- Outcome
- lost growth-promoting abilitye0
- Value
- sevene0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“seven were confirmed to have lost growth-promoting ability”
t0“potatoes”
Claim · model-written summary
Other bacterial genera did not increase potato plantlet growth.
- Taxon
- potatoSolanum tuberosume0
- Treatment
- Bacteria from different generae1
- Outcome
- growth of potato plantletse0
- Direction
- None of these bacteria increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“None of these bacteria increased the growth of potato plantlets”
e1“Bacteria from different genera were also screened with this bioassay.”
Claim · model-written summary
Several other bacterial isolates inhibited potato root and haulm growth.
- Taxon
- potatoSolanum tuberosume0
- Treatment
- Bacteria from different generae1
- Outcome
- root and haulm growthe0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“None of these bacteria increased the growth of potato plantlets, but several inhibited root and haulm growth.”
e1“Bacteria from different genera were also screened with this bioassay.”
The same questions in other papers
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inoculation · growth · Solanum tuberosum (potato)Positive and negative results
81 papers in the same direction as this paper · 22 in the opposite direction
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100 papers more in this group
See all 104 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.