Abstract
Saline-alkaline stress is one of several major abiotic stresses in crop production. Exogenous spermidine (Spd) can effectively increase tomato saline-alkaline stress resistance by relieving membrane lipid peroxidation damage. However, the mechanism through which exogenous Spd pre-treatment triggers the tomato antioxidant system to resist saline-alkaline stress remains unclear. Whether H2O2 and polyamine oxidase (PAO) are involved in Spd-induced tomato saline-alkaline stress tolerance needs to be determined. Here, we investigated the role of PAO and H2O2 in exogenous Spd-induced tolerance of tomato to saline-alkaline stress. Results showed that Spd application increased the expression and activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), and the ratio of reduced ascorbate (AsA) and glutathione (GSH) contents under saline-alkaline stress condition. Exogenous Spd treatment triggered endogenous H2O2 levels, SlPAO4 gene expression, as well as PAO activity under normal conditions. Inhibiting endogenous PAO activity by 1,8-diaminooctane (1,8-DO, an inhibitor of polyamine oxidase) significantly reduced H2O2 levels in the later stage. Moreover, inhibiting endogenous PAO or silencing the SlPAO4 gene increased the peroxidation damage of tomato leaves under saline-alkaline stress. These findings indicated that exogenous Spd treatment stimulated SlPAO4 gene expression and increased PAO activity, which mediated the elevation of H2O2 level under normal conditions. Consequently, the downstream antioxidant system was activated to eliminate excessive ROS accumulation and relieve membrane lipid peroxidation damage and growth inhibition under saline-alkaline stress. In conclusion, PAO triggered H2O2-mediated Spd-induced increase in the tolerance of tomato to saline-alkaline stress.
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Claims 7
Claim · model-written summary
Spermidine raised SOD, CAT and APX expression and activity under saline alkaline stress.
- Taxon
- tomato
Solanum lycopersicumt0 - Treatment
- Spd applicatione0
- Outcome
- expression and activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX)e0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Spd application increased the expression and activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX)”
t0“Tomato Seedlings”
Claim · model-written summary
Spermidine raised GR expression and activity and reduced ascorbate and glutathione ratio.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- Spd applicatione1
- Outcome
- glutathione reductase (GR), and the ratio of reduced ascorbate (AsA) and glutathione (GSH) contentse0
- Direction
- increasede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“glutathione reductase (GR), and the ratio of reduced ascorbate (AsA) and glutathione (GSH) contents under saline-alkaline stress condition”
t0“Tomato Seedlings”
e1“Spd application increased the expression and activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX)”
e2“Spd application increased the expression and activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX)”
Claim · model-written summary
Spermidine increased endogenous hydrogen peroxide under normal conditions.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- Exogenous Spd treatmente0
- Outcome
- endogenous H2O2 levelse0
- Direction
- triggerede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenous Spd treatment triggered endogenous H2O2 levels, SlPAO4 gene expression, as well as PAO activity under normal conditions”
t0“Tomato Seedlings”
Claim · model-written summary
Spermidine induced SlPAO4 expression and PAO activity under normal conditions.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- Exogenous Spd treatmente0
- Gene
- SlPAO4e0
- Outcome
- SlPAO4 gene expression, as well as PAO activitye0
- Direction
- triggerede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenous Spd treatment triggered endogenous H2O2 levels, SlPAO4 gene expression, as well as PAO activity under normal conditions”
t0“Tomato Seedlings”
Claim · model-written summary
PAO inhibition lowered later hydrogen peroxide levels.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- Inhibiting endogenous PAO activity by 1,8-diaminooctanee0
- Gene
- PAOe0
- Outcome
- H2O2 levelse0
- Direction
- reducede0
- Qualifier
- in the later stagee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inhibiting endogenous PAO activity by 1,8-diaminooctane (1,8-DO, an inhibitor of polyamine oxidase) significantly reduced H2O2 levels in the later stage”
t0“Tomato Seedlings”
Claim · model-written summary
PAO inhibition increased tomato leaf peroxidation damage under stress.
- Taxon
- tomatoSolanum lycopersicume0
- Treatment
- inhibiting endogenous PAOe0
- Gene
- PAOe0
- Outcome
- peroxidation damage of tomato leavese0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“inhibiting endogenous PAO or silencing the SlPAO4 gene increased the peroxidation damage of tomato leaves under saline-alkaline stress”
Claim · model-written summary
SlPAO4 silencing increased tomato leaf peroxidation damage under stress.
- Taxon
- tomatoSolanum lycopersicume0
- Treatment
- silencing the SlPAO4 genee0
- Gene
- SlPAO4e0
- Outcome
- peroxidation damage of tomato leavese0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“silencing the SlPAO4 gene increased the peroxidation damage of tomato leaves under saline-alkaline stress”
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