Abstract
Important functions of the plant hormone abscisic acid (ABA) in stress reactions, growth and photosynthetic processes are extensively studied in the model plant Arabidopsis thaliana. This paper investigates the importance of Moco-sulphurase ABA3 and aldehyde oxidase (AO) on ABA-biosynthesis in Populus × canescens. ABA3 is essential for activation of the molybdenum enzymes AO and xanthine dehydrogenase (XDH). AO itself catalyzes the last step in ABA-biosynthesis. Generation of transgenic poplar plants altered in ABA3 and AO-activity using RNAi knock down and overexpression was performed. Whereas RNAi-AO plants show a specific loss of AO activity, the RNAi-ABA3 plants has a strongly reduced activity of both molybdenum enzymes: AO and XDH. Constructs of AO and ABA3-promoters fused to β-glucuronidase provide the basis to investigate transcriptional regulation of ABA-biosynthetic processes under stress conditions. Application of high salt concentrations and different drought stress intensities does change the endogenous AO or XDH neither on the side of transcription nor on protein activity. On phytohormone level however, water loss leads to increased ABA-amounts regardless of whether transgenic or wildtype plants are studied. Salt application resulted in higher ABA-levels in all analyzed plant lines. The down regulation of AO in the two different RNAi-plant lines strongly prevented a wildtype-like increase of ABA-levels. Whereas the WT plants accumulated up to 6000 ng ABA g-1 FW-1 after 16 h of salt stress exposure, plants of the RNAi lines revealed a markedly lower increase of only up to 2000 ng ABA g-1 FW-1. Opposing to these observations, ABA-levels increased during drought without any influence by the RNAi-effect. These results revealed that although stresses did not result in a visible increased AO-activity, ABA-production was influenced by AO and ABA3 at least under salinity.
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Claims 11
Claim · model-written summary
RNAi-AO poplar specifically lost AO activity.
- Taxon
- Populus × canescens
Populus tremula ×Populus albae2 - Material
- RNAi-AO plantse0
- Treatment
- RNAi-AOe0
- Gene
- AOe0
- Outcome
- AO activitye0
- Direction
- losse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RNAi-AO plants show a specific loss of AO activity”
t0“Poplar Plants”
e2“in Populus × canescens”
Claim · model-written summary
RNAi-ABA3 poplar had strongly reduced AO activity.
- Material
- RNAi-ABA3 plantse0
- Treatment
- RNAi-ABA3e0
- Gene
- AOe0
- Outcome
- activity of both molybdenum enzymes: AO and XDHe0
- Direction
- reducede0
PopulusNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RNAi-ABA3 plants has a strongly reduced activity of both molybdenum enzymes: AO and XDH”
t0“Poplar Plants”
Claim · model-written summary
RNAi-ABA3 poplar had strongly reduced XDH activity.
- Material
- RNAi-ABA3 plantse0
- Treatment
- RNAi-ABA3e0
- Gene
- XDHe0
- Outcome
- activity of both molybdenum enzymes: AO and XDHe0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RNAi-ABA3 plants has a strongly reduced activity of both molybdenum enzymes: AO and XDH”
t0“Poplar Plants”
Claim · model-written summary
High salt and drought did not change AO transcription or protein activity.
- Treatment
- high salt concentrationse0
- Gene
- AOe0
- Outcome
- transcription nor on protein activitye0
- Direction
- does changee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Application of high salt concentrations and different drought stress intensities does change the endogenous AO or XDH neither on the side of transcription nor on protein activity”
t0“Poplar Plants”
Claim · model-written summary
High salt and drought did not change XDH transcription or protein activity.
- Treatment
- different drought stress intensitiese0
- Gene
- XDHe0
- Outcome
- transcription nor on protein activitye0
- Direction
- does changee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Application of high salt concentrations and different drought stress intensities does change the endogenous AO or XDH neither on the side of transcription nor on protein activity”
t0“Poplar Plants”
Claim · model-written summary
Water loss increased ABA amounts in transgenic and wildtype poplar.
- Treatment
- water losse0
- Outcome
- ABA-amountse0
- Direction
- increasede0
- Qualifier
- regardless of whether transgenic or wildtype plants are studiede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“water loss leads to increased ABA-amounts regardless of whether transgenic or wildtype plants are studied”
t0“Poplar Plants”
Claim · model-written summary
Salt increased ABA levels in all analyzed poplar lines.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Salt application resulted in higher ABA-levels in all analyzed plant lines”
t0“Poplar Plants”
Claim · model-written summary
AO downregulation in RNAi lines limited the salt-induced ABA increase.
- Treatment
- down regulation of AOe0
- Gene
- AOe0
- Outcome
- increase of ABA-levelse0
- Direction
- preventede0
- Comparator
- wildtypee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The down regulation of AO in the two different RNAi-plant lines strongly prevented a wildtype-like increase of ABA-levels”
t0“Poplar Plants”
Claim · model-written summary
Salt-stressed WT poplar accumulated up to 6000 ng ABA g-1 FW-1 after 16 hours.
- Material
- WT plantse0
- Outcome
- ABAe0
- Value
- 6000 ng ABA g-1 FW-1e0
- Qualifier
- after 16 h of salt stress exposuree0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“WT plants accumulated up to 6000 ng ABA g-1 FW-1 after 16 h of salt stress exposure”
t0“Poplar Plants”
Claim · model-written summary
Salt-stressed RNAi poplar showed an increase of only up to 2000 ng ABA g-1 FW-1.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“plants of the RNAi lines revealed a markedly lower increase of only up to 2000 ng ABA g-1 FW-1”
t0“Poplar Plants”
Claim · model-written summary
Drought increased ABA levels regardless of the RNAi effect.
- Treatment
- droughte0
- Outcome
- ABA-levelse0
- Direction
- increasede0
- Qualifier
- without any influence by the RNAi-effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ABA-levels increased during drought without any influence by the RNAi-effect”
t0“Poplar Plants”
The same questions in other papers
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- positive
- positive
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See all 11 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.