Abstract
BACKGROUND AND AIMS: Abiotic stresses stimulate formation of active oxygen species in plant tissues. Among antioxidant mechanisms, H2O2 detoxication by ascorbate peroxidases (APX) plays an important role. Several APX isoforms exist in plant cells, and they have rarely been studied separately. The aim of this work was to study changes in cytosolic, peroxisomal, stromatic and thylakoid APX gene expression in response to progressive drought, rapid desiccation and application of exogenous abscisic acid in the leaves of cowpea (Vigna unguiculata) plants. METHODS: Two cowpea (V. unguiculata) cultivars, 'EPACE-1' which is drought-tolerant and '1183'which is drought-sensitive, were submitted to drought stress by withholding irrigation. Detached leaves were air-dried or treated with exogenous abscisic acid. APX cDNAs were isolated by PCR and cloned in plasmid vectors. Changes in gene expression were studied using reverse-transcription PCR. KEY RESULTS: Four new V. unguiculata cDNAs encoding putative cytosolic, peroxisomal and chloroplastic (stromatic and thylakoidal) APX were isolated and characterized. In response to the different treatments, higher increases in steady-state transcript levels of the cytoplasmic and peroxisomal APX genes were observed in '1183' compared with 'EPACE-1'. On the other hand, the expression of the chloroplastic APX genes was stimulated earlier in the tolerant cultivar when submitted to progressive drought. CONCLUSIONS: Water deficit induced differences in transcript accumulation of APX genes between the two cultivars that were related to their respective tolerance to drought. Chloroplastic APX genes responded early to progressive water deficit in the tolerant plant, suggesting a capacity to efficiently detoxify active oxygen species at their production site. The more sensitive '1183' was also able to respond to drought by activating its whole set of APX genes.
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Claims 6
Claim · model-written summary
Four cowpea cDNAs encoding putative cytosolic, peroxisomal and chloroplastic APX were isolated and characterized.
- Taxon
- V. unguiculata
Vigna unguiculatae0 - Gene
- APXe0
- Outcome
- cDNAs encoding putative cytosolic, peroxisomal and chloroplastic (stromatic and thylakoidal) APXe0
- Value
- Foure0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Four new V. unguiculata cDNAs encoding putative cytosolic, peroxisomal and chloroplastic (stromatic and thylakoidal) APX were isolated and characterized.”
t0“Cowpea”
Claim · model-written summary
Cytoplasmic and peroxisomal APX transcript levels increased more in 1183 than in EPACE-1 after treatment.
- Taxon
- CowpeaVigna unguiculatat0
- Material
- '1183'e0
- Gene
- APXe0
- Outcome
- steady-state transcript levels of the cytoplasmic and peroxisomal APX genese0
- Direction
- higher increasese0
- Comparator
- 'EPACE-1'e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“higher increases in steady-state transcript levels of the cytoplasmic and peroxisomal APX genes were observed in '1183' compared with 'EPACE-1'.”
t0“Cowpea”
Claim · model-written summary
Chloroplastic APX expression was stimulated earlier in the tolerant cultivar under progressive drought.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- progressive droughte0
- Gene
- APXe0
- Outcome
- expression of the chloroplastic APX genese0
- Direction
- stimulated earliere0
- Qualifier
- tolerant cultivare0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the expression of the chloroplastic APX genes was stimulated earlier in the tolerant cultivar when submitted to progressive drought.”
t0“Cowpea”
Claim · model-written summary
Water deficit caused cultivar differences in APX transcript accumulation related to drought tolerance.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- Water deficite0
- Gene
- APXe0
- Outcome
- transcript accumulation of APX genese0
- Qualifier
- related to their respective tolerance to droughte0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Water deficit induced differences in transcript accumulation of APX genes between the two cultivars that were related to their respective tolerance to drought.”
t0“Cowpea”
Claim · model-written summary
Early chloroplastic APX response in the tolerant cultivar suggests capacity to detoxify active oxygen species at their production site.
- Taxon
- CowpeaVigna unguiculatat0
- Gene
- APXe0
- Outcome
- capacity to efficiently detoxify active oxygen speciese0
- Qualifier
- at their production sitee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chloroplastic APX genes responded early to progressive water deficit in the tolerant plant, suggesting a capacity to efficiently detoxify active oxygen species at their production site.”
t0“Cowpea”
Claim · model-written summary
The sensitive 1183 cultivar activated its whole set of APX genes in response to drought.
- Taxon
- CowpeaVigna unguiculatat0
- Material
- '1183'e0
- Treatment
- droughte0
- Gene
- APXe0
- Outcome
- activating its whole set of APX genese0
- Direction
- activatinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The more sensitive '1183' was also able to respond to drought by activating its whole set of APX genes.”
t0“Cowpea”
The same questions in other papers
drought · physiology: antioxidant enzymes · Vigna unguiculata (cowpea)Results agree
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See all 7 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.