Abstract
The plant hormone abscisic acid (ABA) plays important roles in seed maturation and dormancy and in adaptation to a variety of environmental stresses. An effort to engineer plants with elevated ABA levels and subsequent stress tolerance is focused on the genetic manipulation of the cleavage reaction. It has been shown in bean (Phaseolus vulgaris) that the gene encoding the cleavage enzyme (PvNCED1) is up-regulated by water stress, preceding accumulation of ABA. Transgenic wild tobacco (Nicotiana plumbaginifolia Viv.) plants were produced that overexpress the PvNCED1 gene either constitutively or in an inducible manner. The constitutive expression of PvNCED1 resulted in an increase in ABA and its catabolite, phaseic acid (PA). When the PvNCED1 gene was driven by the dexamethasone (DEX)-inducible promoter, a transient induction of PvNCED1 message and accumulation of ABA and PA were observed in different lines after application of DEX. Accumulation of ABA started to level off after 6 h, whereas the PA level continued to increase. In the presence of DEX, seeds from homozygous transgenic line TN1 showed a 4-d delay in germination. After spraying with DEX, the detached leaves from line TN1 had a drastic decrease in their water loss relative to control leaves. These plants also showed a marked increase in their tolerance to drought stress. These results indicate that it is possible to manipulate ABA levels in plants by overexpressing the key regulatory gene in ABA biosynthesis and that stress tolerance can be improved by increasing ABA levels.
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Claims 9
Claim · model-written summary
Constitutive expression of PvNCED1 increased ABA and phaseic acid levels in Nicotiana plumbaginifolia.
- Taxon
- Nicotiana plumbaginifolia
Nicotiana plumbaginifoliat0 - Treatment
- constitutive expression of PvNCED1e1
- Gene
- PvNCED1e1
- Outcome
- ABA and its catabolite, phaseic acid (PA)e1
- Direction
- increasee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nicotiana plumbaginifolia”
e1“The constitutive expression of PvNCED1 resulted in an increase in ABA and its catabolite, phaseic acid (PA)”
Claim · model-written summary
After application of DEX, PvNCED1 message was transiently induced and ABA and PA accumulated in different lines.
- Taxon
- Nicotiana plumbaginifoliaNicotiana plumbaginifoliat0
- Treatment
- application of DEXe2
- Gene
- PvNCED1e2
- Outcome
- accumulation of ABA and PAe2
- Direction
- increaseinferrede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nicotiana plumbaginifolia”
e2“When the PvNCED1 gene was driven by the dexamethasone (DEX)-inducible promoter, a transient induction of PvNCED1 message and accumulation of ABA and PA were observed in different lines after application of DEX”
Claim · model-written summary
Accumulation of ABA started to level off after 6 h in the transgenic tobacco.
- Taxon
- Nicotiana plumbaginifoliaNicotiana plumbaginifoliat0
- Outcome
- Accumulation of ABAe3
- Qualifier
- after 6 he3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nicotiana plumbaginifolia”
e3“Accumulation of ABA started to level off after 6 h”
Claim · model-written summary
The PA level continued to increase after ABA accumulation levelled off in the transgenic tobacco.
- Taxon
- Nicotiana plumbaginifoliaNicotiana plumbaginifoliat0
- Outcome
- PA levele4
- Direction
- continued to increasee4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nicotiana plumbaginifolia”
e4“whereas the PA level continued to increase”
Claim · model-written summary
In the presence of DEX, seeds of homozygous transgenic line TN1 showed a 4-day delay in germination.
- Taxon
- Nicotiana plumbaginifoliaNicotiana plumbaginifoliat0
- Material
- homozygous transgenic line TN1e5
- Organ / stage
- seedse5
- Treatment
- the presence of DEXe5
- Outcome
- germinatione5
- Direction
- delaye5
- Value
- 4-d delaye5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nicotiana plumbaginifolia”
e5“In the presence of DEX, seeds from homozygous transgenic line TN1 showed a 4-d delay in germination”
Claim · model-written summary
After DEX spraying, detached leaves of line TN1 had a drastic decrease in water loss relative to control leaves.
- Taxon
- Nicotiana plumbaginifoliaNicotiana plumbaginifoliat0
- Material
- line TN1e6
- Organ / stage
- detached leavese6
- Treatment
- spraying with DEXe6
- Outcome
- water losse6
- Direction
- decreasee6
- Comparator
- control leavese6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nicotiana plumbaginifolia”
e6“After spraying with DEX, the detached leaves from line TN1 had a drastic decrease in their water loss relative to control leaves”
Claim · model-written summary
Transgenic tobacco plants showed a marked increase in tolerance to drought stress.
- Taxon
- Nicotiana plumbaginifoliaNicotiana plumbaginifoliat0
- Treatment
- drought stresse7
- Outcome
- tolerance to drought stresse7
- Direction
- increasee7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nicotiana plumbaginifolia”
e7“These plants also showed a marked increase in their tolerance to drought stress”
Claim · model-written summary
Manipulating ABA levels in tobacco plants is possible by overexpressing the key regulatory gene of ABA biosynthesis.
- Taxon
- Nicotiana plumbaginifoliaNicotiana plumbaginifoliat0
- Gene
- key regulatory gene in ABA biosynthesise0
- Outcome
- manipulate ABA levels in plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nicotiana plumbaginifolia”
e0“These results indicate that it is possible to manipulate ABA levels in plants by overexpressing the key regulatory gene in ABA biosynthesis”
Claim · model-written summary
Stress tolerance can be improved by increasing ABA levels.
- Taxon
- Nicotiana plumbaginifoliaNicotiana plumbaginifoliat0
- Compound
- ABAe1
- Outcome
- stress tolerance can be improvede1
- Qualifier
- by increasing ABA levelse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Nicotiana plumbaginifolia”
e1“stress tolerance can be improved by increasing ABA levels”