Abstract
Excess active oxygen is generated during the hypersensitive reaction (HR), an incompatible reaction of plants to bacterial pathogens. During HR, lipid peroxidation correlates chronologically with production of the oxygen species, superoxide (O(2) (.-)). However, O(2) (.-) may not be the active oxygen species that initiates lipid peroxidation. Evidence from other systems suggest that O(2) (.-) is converted to the hydroxyl radical (HO(.)) before lipid peroxidation is initiated. Until recently, HO(.) could not be detected directly in vivo. This study utilizes a newly reported method to directly detect and quantify the formation of HO(.)in vivo. Dimethyl sulfoxide (DMSO), used as a molecular probe, is oxidized by HO(.), forming the stable compound methanesulfinic acid. The methanesulfinic acid can be easily extracted from plant tissues and measured with a colorimetric assay. This study demonstrates significant increases in HO(.) concentration after simultaneous infiltration of cucumber (Cucumis sativa L.) plants with paraquat and DMSO. The concentration of HO(.) did not increase significantly when cucumber plants were infiltrated simultaneously with the HR-inducing bacteria, Pseudomonas syringae pv. pisi, and with DMSO. Lipid peroxidation, however, could be measured at times when HO(.) was not detectable. It appears that HO(.) is not generated during bacteria-induced HR; therefore, HO(.) is not responsible for the initiation of lipid peroxidation.
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Claims 4
Claim · model-written summary
Paraquat and DMSO infiltration significantly increased hydroxyl radical concentration in cucumber.
- Taxon
- cucumber (Cucumis sativa L.)
Cucumis sativuse0 - Treatment
- simultaneous infiltration of cucumber (Cucumis sativa L.) plants with paraquat and DMSOe0
- Outcome
- HO(.) concentratione0
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significant increases in HO(.) concentration after simultaneous infiltration of cucumber (Cucumis sativa L.) plants with paraquat and DMSO”
Claim · model-written summary
Infiltration with Pseudomonas syringae pv. pisi and DMSO did not significantly increase cucumber hydroxyl radical concentration.
- Taxon
- cucumber plantsCucumis sativuse0
- Treatment
- infiltrated simultaneously with the HR-inducing bacteria, Pseudomonas syringae pv. pisi, and with DMSOe0
- Interactor
- Pseudomonas syringae pv. pisi
Pseudomonas syringae pv. pisie0pathogen - Outcome
- concentration of HO(.)e0
- Direction
- did not increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The concentration of HO(.) did not increase significantly when cucumber plants were infiltrated simultaneously with the HR-inducing bacteria, Pseudomonas syringae pv. pisi, and with DMSO.”
Claim · model-written summary
Lipid peroxidation was measurable when hydroxyl radical was undetectable.
- Taxon
- cucumber plantsCucumis sativuse1
- Outcome
- Lipid peroxidatione0
- Qualifier
- at times when HO(.) was not detectablee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Lipid peroxidation, however, could be measured at times when HO(.) was not detectable.”
e1“cucumber plants”
Claim · model-written summary
The authors inferred that hydroxyl radical is absent during bacteria-induced hypersensitive response and does not initiate lipid peroxidation.
- Taxon
- cucumber plantsCucumis sativuse1
- Outcome
- initiation of lipid peroxidatione0
- Qualifier
- HO(.) is not generated during bacteria-induced HRe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It appears that HO(.) is not generated during bacteria-induced HR; therefore, HO(.) is not responsible for the initiation of lipid peroxidation.”
e1“cucumber plants”
The same questions in other papers
inoculation · molecular: metabolites · Cucumis sativus (cucumber)Positive and negative results
22 in the opposite direction
- positive
- positive
- positive
19 papers more in this group
See all 23 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.