Abstract
Pseudomonas syringae pv. tomato, the causal agent of bacterial speck of tomato, and the plant growth-promoting bacterium Azospirillum brasilense were inoculated onto tomato plants, either alone, as a mixed culture, or consecutively. The population dynamics in the rhizosphere and foliage, the development of bacterial speck disease, and their effects on plant growth were monitored. When inoculated onto separate plants, the A. brasilense population in the rhizosphere of tomato plants was 2 orders of magnitude greater than the population of P. syringae pv. tomato (10(7) versus 10(5) CFU/g [dry weight] of root). Under mist chamber conditions, the leaf population of P. syringae pv. tomato was 1 order of magnitude greater than that of A. brasilense (10(7) versus 10(6) CFU/g [dry weight] of leaf). Inoculation of seeds with a mixed culture of the two bacterial strains resulted in a reduction of the pathogen population in the rhizosphere, an increase in the A. brasilense population, the prevention of bacterial speck disease development, and improved plant growth. Inoculation of leaves with the mixed bacterial culture under mist conditions significantly reduced the P. syringae pv. tomato population and significantly decreased disease severity. Challenge with P. syringae pv. tomato after A. brasilense was established in the leaves further reduced both the population of P. syringae pv. tomato and disease severity and significantly enhanced plant development. Both bacteria maintained a large population in the rhizosphere for 45 days when each was inoculated separately onto tomato seeds (10(5) to 10(6) CFU/g [dry weight] of root). However, P. syringae pv. tomato did not survive in the rhizosphere in the presence of A. brasilense. Foliar inoculation of A. brasilense after P. syringae pv. tomato was established on the leaves did not alleviate bacterial speck disease, and A. brasilense did not survive well in the phyllosphere under these conditions, even in a mist chamber. Several applications of a low concentration of buffered malic acid significantly enhanced the leaf population of A. brasilense (>10(8) CFU/g [dry weight] of leaf), decreased the population of P. syringae pv. tomato to almost undetectable levels, almost eliminated disease development, and improved plant growth to the level of uninoculated healthy control plants. Based on our results, we propose that A. brasilense be used in prevention programs to combat the foliar bacterial speck disease caused by P. syringae pv. tomato.
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Claims 16
Claim · model-written summary
A. brasilense rhizosphere population exceeded P. syringae by two orders of magnitude.
- Taxon
- tomato
Solanum lycopersicume0 - Interactor
- A. brasilense
Azospirillum brasilensee0symbiont - Second interactor
- P. syringae pv. tomato
Pseudomonas syringae pv. tomatoe0pathogen - Outcome
- A. brasilense population in the rhizospheree0
- Direction
- greatere0
- Value
- 2 orders of magnitudee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A. brasilense population in the rhizosphere of tomato plants was 2 orders of magnitude greater than the population of P. syringae pv. tomato (10(7) versus 10(5) CFU/g [dry weight] of root)”
Claim · model-written summary
P. syringae leaf population exceeded A. brasilense by one order under mist.
- Taxon
- TomatoSolanum lycopersicumt0
- Interactor
- P. syringae pv. tomatoPseudomonas syringae pv. tomatoe0pathogen
- Second interactor
- A. brasilenseAzospirillum brasilensee0symbiont
- Outcome
- leaf population of P. syringae pv. tomatoe0
- Direction
- greatere0
- Value
- 1 order of magnitudee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“leaf population of P. syringae pv. tomato was 1 order of magnitude greater than that of A. brasilense”
t0“Protection of Tomato Seedlings”
Claim · model-written summary
Mixed seed inoculation reduced pathogen rhizosphere population.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- Inoculation of seeds with a mixed culture of the two bacterial strainse0
- Outcome
- pathogen population in the rhizospheree0
- Direction
- reductione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculation of seeds with a mixed culture of the two bacterial strains resulted in a reduction of the pathogen population in the rhizosphere”
t0“Protection of Tomato Seedlings”
Claim · model-written summary
Mixed seed inoculation increased A. brasilense population.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- mixed culturee0
- Interactor
- A. brasilenseAzospirillum brasilensee0symbiont
- Outcome
- A. brasilense populatione0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculation of seeds with a mixed culture of the two bacterial strains resulted in a reduction of the pathogen population in the rhizosphere, an increase in the A. brasilense population”
t0“Protection of Tomato Seedlings”
Claim · model-written summary
Mixed seed inoculation prevented bacterial speck and improved growth.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- mixed culturee0
- Outcome
- bacterial speck disease development, and improved plant growthe0
- Direction
- improvede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculation of seeds with a mixed culture of the two bacterial strains resulted in a reduction of the pathogen population in the rhizosphere, an increase in the A. brasilense population, the prevention of bacterial speck disease development, and improved plant growth”
t0“Protection of Tomato Seedlings”
Claim · model-written summary
Mixed foliar inoculation reduced P. syringae population and disease severity.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- Inoculation of leaves with the mixed bacterial culturee0
- Interactor
- P. syringae pv. tomatoPseudomonas syringae pv. tomatoe0pathogen
- Outcome
- P. syringae pv. tomato population and significantly decreased disease severitye0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inoculation of leaves with the mixed bacterial culture under mist conditions significantly reduced the P. syringae pv. tomato population and significantly decreased disease severity”
t0“Protection of Tomato Seedlings”
Claim · model-written summary
Challenge after A. brasilense establishment reduced pathogen population and disease severity.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- Challenge with P. syringae pv. tomato after A. brasilense was established in the leavese0
- Interactor
- P. syringae pv. tomatoPseudomonas syringae pv. tomatoe0pathogen
- Second interactor
- A. brasilenseAzospirillum brasilensee0symbiont
- Outcome
- population of P. syringae pv. tomato and disease severitye0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Challenge with P. syringae pv. tomato after A. brasilense was established in the leaves further reduced both the population of P. syringae pv. tomato and disease severity”
t0“Protection of Tomato Seedlings”
Claim · model-written summary
Challenge after A. brasilense establishment enhanced plant development.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- A. brasilensee0
- Outcome
- plant developmente0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Challenge with P. syringae pv. tomato after A. brasilense was established in the leaves further reduced both the population of P. syringae pv. tomato and disease severity and significantly enhanced plant development”
t0“Protection of Tomato Seedlings”
Claim · model-written summary
Both bacteria maintained large rhizosphere populations for 45 days when separately inoculated.
- Taxon
- tomatoSolanum lycopersicume0
- Outcome
- large population in the rhizospheree0
- Value
- 10(5) to 10(6) CFU/g [dry weight] of roote0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both bacteria maintained a large population in the rhizosphere for 45 days when each was inoculated separately onto tomato seeds (10(5) to 10(6) CFU/g [dry weight] of root)”
Claim · model-written summary
P. syringae did not survive in rhizosphere with A. brasilense.
- Taxon
- TomatoSolanum lycopersicumt0
- Interactor
- P. syringae pv. tomatoPseudomonas syringae pv. tomatoe0pathogen
- Second interactor
- A. brasilenseAzospirillum brasilensee0symbiont
- Outcome
- P. syringae pv. tomato did not survive in the rhizospheree0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“P. syringae pv. tomato did not survive in the rhizosphere in the presence of A. brasilense”
t0“Protection of Tomato Seedlings”
Claim · model-written summary
Late A. brasilense foliar inoculation did not alleviate disease.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- Foliar inoculation of A. brasilensee0
- Interactor
- P. syringae pv. tomatoPseudomonas syringae pv. tomatoe0pathogen
- Second interactor
- A. brasilenseAzospirillum brasilensee0symbiont
- Outcome
- bacterial speck diseasee0
- Direction
- did not alleviatee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Foliar inoculation of A. brasilense after P. syringae pv. tomato was established on the leaves did not alleviate bacterial speck disease”
t0“Protection of Tomato Seedlings”
Claim · model-written summary
Late A. brasilense inoculation did not survive well in the phyllosphere.
- Taxon
- TomatoSolanum lycopersicumt0
- Interactor
- A. brasilenseAzospirillum brasilensee0symbiont
- Outcome
- A. brasilense did not survive well in the phyllospheree0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A. brasilense did not survive well in the phyllosphere under these conditions”
t0“Protection of Tomato Seedlings”
Claim · model-written summary
Buffered malic acid applications increased A. brasilense leaf populations.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- Several applications of a low concentration of buffered malic acide0
- Interactor
- A. brasilenseAzospirillum brasilensee0symbiont
- Outcome
- leaf population of A. brasilensee0
- Direction
- enhancede0
- Value
- >10(8) CFU/g [dry weight] of leafe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Several applications of a low concentration of buffered malic acid significantly enhanced the leaf population of A. brasilense (>10(8) CFU/g [dry weight] of leaf)”
t0“Protection of Tomato Seedlings”
Claim · model-written summary
Buffered malic acid lowered pathogen population nearly to undetectable levels.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- buffered malic acide0
- Interactor
- P. syringae pv. tomatoPseudomonas syringae pv. tomatoe0pathogen
- Outcome
- population of P. syringae pv. tomatoe0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Several applications of a low concentration of buffered malic acid significantly enhanced the leaf population of A. brasilense (>10(8) CFU/g [dry weight] of leaf), decreased the population of P. syringae pv. tomato to almost undetectable levels”
t0“Protection of Tomato Seedlings”
Claim · model-written summary
Buffered malic acid almost eliminated disease and restored growth.
- Taxon
- TomatoSolanum lycopersicumt0
- Treatment
- buffered malic acide0
- Outcome
- disease development, and improved plant growthe0
- Direction
- improvede0
- Comparator
- uninoculated healthy control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Several applications of a low concentration of buffered malic acid significantly enhanced the leaf population of A. brasilense (>10(8) CFU/g [dry weight] of leaf), decreased the population of P. syringae pv. tomato to almost undetectable levels, almost eliminated disease development, and improved plant growth to the level of uninoculated healthy control plants”
t0“Protection of Tomato Seedlings”
Claim · model-written summary
The authors propose A. brasilense for bacterial speck prevention.
- Taxon
- TomatoSolanum lycopersicumt0
- Interactor
- P. syringae pv. tomatoPseudomonas syringae pv. tomatoe0pathogen
- Second interactor
- A. brasilenseAzospirillum brasilensee0symbiont
- Outcome
- A. brasilense be used in prevention programse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“we propose that A. brasilense be used in prevention programs to combat the foliar bacterial speck disease caused by P. syringae pv. tomato”
t0“Protection of Tomato Seedlings”
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