Abstract
Water stress accelerates the generation of reactive oxygen species, which trigger a cascade of antioxidative defence mechanisms comprising enzymatic and nonenzymatic antioxidants. The aim of this study was to investigate the oxidative damage and the antioxidative defence systems in seedlings of the water stress-tolerant (B71) and the sensitive (B59) inbred lines of sunflower (Helianthus annuus L.) in response to water stress and rewatering. In addition, we characterised the transcriptomic profile associated with enzymatic antioxidative defence. An elevated electrolyte leakage in B59 indicated increased plasmatic membrane permeability, which correlated with greater sensitivity to water stress. In response to water stress, both lines showed an increase in malondialdehyde and H2O2 content but these increases were more noticeable in the sensitive line. In both lines, an increase in enzymatic activity (e.g. peroxidase and ascorbate peroxidase) was not sufficient to overcome the H2O2 accumulation triggered by water stress. Upon water stress, the overall expression level of genes associated with the enzymatic antioxidant system increased in B71 and decreased in B59, which showed downregulated levels of most genes in the shoots. The general profile of phenolic compounds was clearly different between organs and between inbred lines. The B59 line activated nonenzymatic antioxidant responses to counteract the oxidative stress caused by water stress. The tolerance of B71 to water stress could be associated with compensatory antioxidant mechanisms based on the expression of genes encoding enzyme components of the ascorbate-glutathione and redoxin cycles, which contributed to explaining, at least partly, the response of this line.
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Claims 8
Claim · model-written summary
B59 had elevated electrolyte leakage correlated with greater water stress sensitivity.
- Taxon
- sunflower (Helianthus annuus L.)
Helianthus annuust0 - Material
- B59e0
- Outcome
- electrolyte leakagee0
- Direction
- elevatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“An elevated electrolyte leakage in B59 indicated increased plasmatic membrane permeability, which correlated with greater sensitivity to water stress.”
t0“sunflower (Helianthus annuus L.)”
Claim · model-written summary
Water stress increased malondialdehyde and H2O2 contents in both lines, more markedly in B59.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuust0
- Treatment
- water stresse1
- Outcome
- malondialdehyde and H2O2 contente0
- Direction
- increasee0
- Qualifier
- more noticeable in the sensitive linee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In response to water stress, both lines showed an increase in malondialdehyde and H2O2 content but these increases were more noticeable in the sensitive line.”
t0“sunflower (Helianthus annuus L.)”
e1“Upon water stress, the overall expression level of genes associated with the enzymatic antioxidant system increased in B71”
Claim · model-written summary
Antioxidant enzyme activity increased in both lines but did not overcome H2O2 accumulation.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuust0
- Treatment
- water stresse1
- Gene
- peroxidase and ascorbate peroxidasee0
- Outcome
- enzymatic activitye0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In both lines, an increase in enzymatic activity (e.g. peroxidase and ascorbate peroxidase) was not sufficient to overcome the H2O2 accumulation triggered by water stress.”
t0“sunflower (Helianthus annuus L.)”
e1“Upon water stress, the overall expression level of genes associated with the enzymatic antioxidant system increased in B71”
Claim · model-written summary
Water stress increased overall antioxidant gene expression in B71.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuust0
- Material
- B71e0
- Treatment
- water stresse1
- Outcome
- overall expression level of genes associated with the enzymatic antioxidant systeme0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Upon water stress, the overall expression level of genes associated with the enzymatic antioxidant system increased in B71”
t0“sunflower (Helianthus annuus L.)”
e1“Upon water stress, the overall expression level of genes associated with the enzymatic antioxidant system increased in B71”
Claim · model-written summary
Water stress decreased overall antioxidant gene expression in B59, with most shoot genes downregulated.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuust0
- Material
- B59e0
- Treatment
- water stresse1
- Outcome
- levels of most genes in the shootse0
- Direction
- downregulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“decreased in B59, which showed downregulated levels of most genes in the shoots”
t0“sunflower (Helianthus annuus L.)”
e1“Upon water stress, the overall expression level of genes associated with the enzymatic antioxidant system increased in B71”
Claim · model-written summary
Phenolic compound profiles differed between organs and inbred lines.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuust0
- Outcome
- general profile of phenolic compoundse0
- Direction
- differente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The general profile of phenolic compounds was clearly different between organs and between inbred lines.”
t0“sunflower (Helianthus annuus L.)”
Claim · model-written summary
B59 activated nonenzymatic antioxidant responses under water stress.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuust0
- Material
- B59e0
- Treatment
- water stresse1
- Outcome
- nonenzymatic antioxidant responsese0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The B59 line activated nonenzymatic antioxidant responses to counteract the oxidative stress caused by water stress.”
t0“sunflower (Helianthus annuus L.)”
e1“Upon water stress, the overall expression level of genes associated with the enzymatic antioxidant system increased in B71”
Claim · model-written summary
B71 water stress tolerance may be linked to antioxidant mechanisms involving ascorbate-glutathione and redoxin cycle genes.
- Taxon
- sunflower (Helianthus annuus L.)Helianthus annuust0
- Material
- B71e0
- Outcome
- tolerance of B71 to water stresse0
- Qualifier
- compensatory antioxidant mechanismse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The tolerance of B71 to water stress could be associated with compensatory antioxidant mechanisms based on the expression of genes encoding enzyme components of the ascorbate-glutathione and redoxin cycles”
t0“sunflower (Helianthus annuus L.)”
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See all 20 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.