Abstract
Pseudomonas syringae pv. tabaci (Pst) is a hemibiotrophic bacterial pathogen responsible for tobacco wildfire disease. Although considerable research has been conducted on the tobacco plant's tolerance to Pst, the role of light in the responses of the photosystems to Pst infection is poorly understood. This study aimed to elucidate the underlying mechanisms of the reduced photosystem damage in tobacco leaves due to Pst infection under light conditions. Compared to dark conditions, Pst infection under light conditions resulted in less chlorophyll degradation and a smaller decline in photosynthetic function. Although the maximal quantum yield of photosystem II (PSII) and the activity of the photosystem I (PSI) complex decreased as Pst infection progressed, damage to PSI and PSII after infection was reduced under light conditions compared to dark conditions. Pst was 17-fold more abundant in tobacco leaves under dark compared to light conditions at 3 days post inoculation (dpi). Additionally, H2O2 accumulated to a high level in tobacco leaves after Pst infection under light conditions; although to a lesser extent, H2O2 accumulation was also significant under dark conditions. Pretreatment with H2O2 alleviated chlorotic lesions and decreased Pst abundance in tobacco leaves at 3 dpi under dark conditions. MV pretreatment had the same effects under light conditions, whereas 3-(3,4-dichlorophenyl)-1,1-dimethylurea pretreatment aggravated chlorotic lesions and increased the Pst population. These results indicate that chlorotic symptoms and the size of the bacterial population are each negatively correlated with H2O2 accumulation. In other words, light appears to suppress the Pst population in tobacco leaves through the accumulation of H2O2 during infection.
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Claims 15
Claim · model-written summary
Light reduced chlorophyll degradation during Pst infection relative to darkness.
- Taxon
- tobacco
Nicotiana tabacumt0 - Treatment
- light conditionse0
- Interactor
- Pste0pathogen
- Outcome
- chlorophyll degradatione0
- Direction
- lesse0
- Comparator
- dark conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to dark conditions, Pst infection under light conditions resulted in less chlorophyll degradation”
t0“Tobacco Leaves”
Claim · model-written summary
Light reduced the decline in photosynthetic function during Pst infection.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- light conditionse0
- Interactor
- Pste0pathogen
- Outcome
- photosynthetic functione0
- Direction
- smaller declinee0
- Comparator
- dark conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to dark conditions, Pst infection under light conditions resulted in less chlorophyll degradation and a smaller decline in photosynthetic function”
t0“Tobacco Leaves”
Claim · model-written summary
PSII maximal quantum yield declined as infection progressed.
- Taxon
- tobaccoNicotiana tabacumt0
- Interactor
- Pste0pathogen
- Outcome
- maximal quantum yield of photosystem II (PSII)e0
- Direction
- decreasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the maximal quantum yield of photosystem II (PSII) and the activity of the photosystem I (PSI) complex decreased as Pst infection progressed”
t0“Tobacco Leaves”
Claim · model-written summary
PSI complex activity declined as infection progressed.
- Taxon
- tobaccoNicotiana tabacumt0
- Interactor
- Pste0pathogen
- Outcome
- activity of the photosystem I (PSI) complexe0
- Direction
- decreasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the maximal quantum yield of photosystem II (PSII) and the activity of the photosystem I (PSI) complex decreased as Pst infection progressed”
t0“Tobacco Leaves”
Claim · model-written summary
Light reduced postinfection damage to PSI and PSII relative to darkness.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- light conditionse0
- Outcome
- damage to PSI and PSIIe0
- Direction
- reducede0
- Comparator
- dark conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“damage to PSI and PSII after infection was reduced under light conditions compared to dark conditions”
t0“Tobacco Leaves”
Claim · model-written summary
Pst was 17-fold more abundant in tobacco leaves in darkness at 3 dpi.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- darke0
- Interactor
- Pste0pathogen
- Outcome
- Pst was 17-fold more abundant in tobacco leavese0
- Direction
- more abundante0
- Value
- 17-folde0
- Comparator
- light conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pst was 17-fold more abundant in tobacco leaves under dark compared to light conditions at 3 days post inoculation (dpi)”
t0“Tobacco Leaves”
Claim · model-written summary
Infection under light caused high H2O2 accumulation.
- Taxon
- tobaccoNicotiana tabacumt0
- Interactor
- Pste0pathogen
- Outcome
- H2O2 accumulatede0
- Direction
- high levele0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“H2O2 accumulated to a high level in tobacco leaves after Pst infection under light conditions”
t0“Tobacco Leaves”
Claim · model-written summary
Infection in darkness also significantly increased H2O2 accumulation, to a lesser extent.
- Taxon
- tobaccoNicotiana tabacumt0
- Outcome
- H2O2 accumulatione0
- Setting
- dark conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“H2O2 accumulation was also significant under dark conditions”
t0“Tobacco Leaves”
Claim · model-written summary
H2O2 pretreatment alleviated chlorotic lesions in darkness.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- Pretreatment with H2O2e0
- Outcome
- chlorotic lesionse0
- Direction
- alleviatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pretreatment with H2O2 alleviated chlorotic lesions and decreased Pst abundance in tobacco leaves at 3 dpi under dark conditions”
t0“Tobacco Leaves”
Claim · model-written summary
H2O2 pretreatment decreased Pst abundance in darkness at 3 dpi.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- Pretreatment with H2O2e0
- Interactor
- Pste0pathogen
- Outcome
- Pst abundancee0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pretreatment with H2O2 alleviated chlorotic lesions and decreased Pst abundance in tobacco leaves at 3 dpi under dark conditions”
t0“Tobacco Leaves”
Claim · model-written summary
MV pretreatment alleviated lesions and decreased Pst abundance in light.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- MV pretreatmente0
- Outcome
- same effectse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“MV pretreatment had the same effects under light conditions”
t0“Tobacco Leaves”
Claim · model-written summary
DCMU pretreatment aggravated chlorotic lesions.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- 3-(3,4-dichlorophenyl)-1,1-dimethylurea pretreatmente0
- Outcome
- chlorotic lesionse0
- Direction
- aggravatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“3-(3,4-dichlorophenyl)-1,1-dimethylurea pretreatment aggravated chlorotic lesions”
t0“Tobacco Leaves”
Claim · model-written summary
DCMU pretreatment increased the Pst population.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- 3-(3,4-dichlorophenyl)-1,1-dimethylurea pretreatmente0
- Interactor
- Pste0pathogen
- Outcome
- Pst populatione0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“3-(3,4-dichlorophenyl)-1,1-dimethylurea pretreatment aggravated chlorotic lesions and increased the Pst population”
t0“Tobacco Leaves”
Claim · model-written summary
Chlorotic symptoms and bacterial population size were negatively correlated with H2O2 accumulation.
- Taxon
- tobaccoNicotiana tabacumt0
- Compound
- H2O2e0
- Outcome
- chlorotic symptoms and the size of the bacterial populatione0
- Direction
- negatively correlatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“chlorotic symptoms and the size of the bacterial population are each negatively correlated with H2O2 accumulation”
t0“Tobacco Leaves”
Claim · model-written summary
The authors infer that light suppresses Pst through H2O2 accumulation.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- lighte0
- Interactor
- Pste0pathogen
- Compound
- H2O2e0
- Outcome
- Pst populatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“light appears to suppress the Pst population in tobacco leaves through the accumulation of H2O2 during infection”
t0“Tobacco Leaves”
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