Abstract
Out of 1,343 mutant lines of rice mutated by sodium azide from the parental Japonica-type variety ‘Tainung 67’ (TNG67), a paraquat-susceptible line 1192 and a paraquat-tolerant line 72 were selected using whole seedlings at the four-leaf stage and leaf segments at the tillering stage as test materials. Further selection from progenies of these two mutant lines yielded the susceptible 1192-11 (S) and tolerant 72-16 (T), which were studied herein. Chlorophyll fluorescence, electrolyte leakage, and lipid peroxidation were measured for leaf segments of rice following treatment with 0.1 mM paraquat. A comparison of these responses among the three rice lines (TNG67, 72-16, and 1192-11), revealed a higher tolerance to paraquat in the tolerant mutant line 72-16 and the parental variety TNG67 than in the susceptible mutant 1192-11. Analysis of the antioxidative system in paraquat-treated leaf segments showed that the reduced form of glutathione (GSH) and the ratio of GSH to total glutathione increased by 3.5-fold within 6 h after treatment (HAT) and up to 5-fold 9 HAT in the T line, as compared with the S line. In view of the high activities of both dehydroascorbate reductase (DHAR) and glutathione reductase (GR) in paraquat-treated leaves of TNG67 and the T line, the antioxidative effect of the ascorbate–glutathione cycle is hereby proposed to play an essential role in paraquat tolerance of rice. Pretreatment of rice segments with spermine enhanced DHAR and GR activities as well as paraquat tolerance of the S line. These results suggest that the activity of ascorbate–glutathione cycle induced by spermine is involved in rice tolerance to this herbicide. Although kinetics studies showed no significant difference among the three rice lines in paraquat inhibition of GR, a lower affinity of enzyme to substrate (K m ) in TNG67 and the T line and a higher maximal reaction rate (V max ) in the T line for the oxidized glutathione substrate (GSSG) were detected. These observations further implicate the importance of glutathione reductase in paraquat tolerance of rice.
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Claims 11
Claim · model-written summary
Rice lines 72-16 and TNG67 showed higher tolerance to paraquat than susceptible mutant 1192-11 after 0.1 mM paraquat treatment.
- Taxon
- rice
Oryza sativae2 - Material
- 72-16e1
- Treatment
- 0.1 mM paraquate2
- Outcome
- tolerance to paraquate1
- Direction
- highere1
- Comparator
- susceptible mutant 1192-11e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“a higher tolerance to paraquat in the tolerant mutant line 72-16 and the parental variety TNG67 than in the susceptible mutant 1192-11”
e2“Chlorophyll fluorescence, electrolyte leakage, and lipid peroxidation were measured for leaf segments of rice following treatment with 0.1 mM paraquat”
Claim · model-written summary
In the T line, GSH and the GSH to total glutathione ratio increased 3.5-fold within 6 h after paraquat treatment compared with the S line.
- Taxon
- riceOryza sativae2
- Material
- T linee3
- Treatment
- 0.1 mM paraquate2
- Outcome
- reduced form of glutathione (GSH) and the ratio of GSH to total glutathionee3
- Direction
- increasede3
- Value
- 3.5-folde3
- Qualifier
- within 6 h after treatment (HAT)e3
- Comparator
- S linee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“Chlorophyll fluorescence, electrolyte leakage, and lipid peroxidation were measured for leaf segments of rice following treatment with 0.1 mM paraquat”
e3“the reduced form of glutathione (GSH) and the ratio of GSH to total glutathione increased by 3.5-fold within 6 h after treatment (HAT) and up to 5-fold 9 HAT in the T line, as compared with the S line”
Claim · model-written summary
In the T line, GSH and the GSH to total glutathione ratio increased up to 5-fold at 9 HAT compared with the S line.
- Taxon
- riceOryza sativae2
- Material
- T linee3
- Treatment
- 0.1 mM paraquate2
- Outcome
- reduced form of glutathione (GSH) and the ratio of GSH to total glutathionee3
- Direction
- increasede3
- Value
- up to 5-folde3
- Qualifier
- 9 HATe3
- Comparator
- S linee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“Chlorophyll fluorescence, electrolyte leakage, and lipid peroxidation were measured for leaf segments of rice following treatment with 0.1 mM paraquat”
e3“the reduced form of glutathione (GSH) and the ratio of GSH to total glutathione increased by 3.5-fold within 6 h after treatment (HAT) and up to 5-fold 9 HAT in the T line, as compared with the S line”
Claim · model-written summary
High DHAR and GR activities in paraquat-treated leaves of TNG67 and the T line suggest that the ascorbate-glutathione cycle plays an essential role in paraquat tolerance of rice.
- Taxon
- riceOryza sativae4
- Gene
- dehydroascorbate reductase (DHAR) and glutathione reductase (GR)e4
- Outcome
- paraquat tolerancee4
- Qualifier
- ascorbate–glutathione cyclee4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“the high activities of both dehydroascorbate reductase (DHAR) and glutathione reductase (GR) in paraquat-treated leaves of TNG67 and the T line, the antioxidative effect of the ascorbate–glutathione cycle is hereby proposed to play an essential role in paraquat tolerance of rice”
Claim · model-written summary
Pretreatment of rice segments with spermine enhanced DHAR and GR activities.
- Taxon
- riceOryza sativae5
- Treatment
- sperminee5
- Outcome
- DHAR and GR activitiese5
- Direction
- enhancede5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“Pretreatment of rice segments with spermine enhanced DHAR and GR activities as well as paraquat tolerance of the S line”
Claim · model-written summary
Pretreatment with spermine enhanced paraquat tolerance of the S line.
- Taxon
- riceOryza sativae5
- Material
- S linee5
- Treatment
- sperminee5
- Outcome
- paraquat tolerance of the S linee5
- Direction
- enhancede5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“Pretreatment of rice segments with spermine enhanced DHAR and GR activities as well as paraquat tolerance of the S line”
Claim · model-written summary
Spermine-induced ascorbate-glutathione cycle activity is suggested to be involved in rice tolerance to paraquat.
- Taxon
- riceOryza sativae6
- Treatment
- sperminee6
- Outcome
- rice tolerance to this herbicidee6
- Qualifier
- ascorbate–glutathione cycle induced by sperminee6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“the activity of ascorbate–glutathione cycle induced by spermine is involved in rice tolerance to this herbicide”
Claim · model-written summary
Kinetic studies showed no significant difference among the three rice lines in paraquat inhibition of GR.
- Taxon
- riceOryza sativae7
- Material
- three rice linese7
- Outcome
- paraquat inhibition of GRe7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“kinetics studies showed no significant difference among the three rice lines in paraquat inhibition of GR”
Claim · model-written summary
The enzyme showed a lower affinity to the oxidized glutathione substrate in TNG67 and the T line.
- Taxon
- riceOryza sativae0
- Material
- TNG67e1
- Compound
- GSSGe1
- Outcome
- affinity of enzyme to substratee1
- Direction
- lowere1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“1,343 mutant lines of rice”
e1“a lower affinity of enzyme to substrate (K m ) in TNG67 and the T line and a higher maximal reaction rate (V max ) in the T line for the oxidized glutathione substrate (GSSG) were detected”
Claim · model-written summary
The T line showed a higher maximal reaction rate for the oxidized glutathione substrate (GSSG).
- Taxon
- riceOryza sativae0
- Material
- T linee1
- Compound
- GSSGe1
- Outcome
- maximal reaction ratee1
- Direction
- highere1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“1,343 mutant lines of rice”
e1“a lower affinity of enzyme to substrate (K m ) in TNG67 and the T line and a higher maximal reaction rate (V max ) in the T line for the oxidized glutathione substrate (GSSG) were detected”
Claim · model-written summary
Glutathione reductase is implicated as important for paraquat tolerance of rice.
- Taxon
- riceOryza sativae2
- Gene
- glutathione reductasee2
- Outcome
- paraquat tolerancee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“These observations further implicate the importance of glutathione reductase in paraquat tolerance of rice”
The same questions in other papers
spermine · disease · Oryza sativa (rice)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
spermine · physiology: antioxidant enzymes · Oryza sativa (rice)Results agree
1 paper in the same direction as this paper
- positive
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.