Abstract
Despite numerous physiological studies addressing the interactions between brassinosteroids (BRs) and auxins, little is known about the underlying molecular mechanisms. We studied the expression of IAA5 and IAA19 in response to treatment with indole acetic acid (IAA) or brassinolide (BL), the most active BR. Exogenous IAA induced these genes quickly and transiently, whereas exogenous BL induced them gradually and continuously. We also found that a fusion of DR5, a synthetic auxin response element, with the GUS (beta-glucuronidase) gene was induced with similar kinetics to those of the IAA5 and IAA19 genes in response to both IAA and BL treatment of transgenic plants. These results suggest that the IAA genes are induced by BL, at least in part, via the activation of the auxin response element. Endogenous IAA levels per gram fresh weight did not increase when seedlings of Arabidopsis wild type (WT) or the BR-deficient mutant det2 were treated with BL. Furthermore, the levels of IAA transcripts were lower in the det2 mutant than in the WT, even though endogenous IAA levels per gram fresh weight were higher in the det2 mutant than in the WT. In conclusion, the lack of evidence for auxin-mediated activation of early auxin-inducible genes in response to BL suggests that the BR and auxin signaling pathways independently activate the transcriptional system of the IAA and DR5-GUS genes.
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Claims 9
Claim · model-written summary
IAA rapidly and transiently induced IAA5 and IAA19.
- Taxon
- Arabidopsis
Arabidopsist0 - Treatment
- Exogenous IAAe0
- Gene
- IAA5t1
- Outcome
- these genese0
- Direction
- inducede0
- Qualifier
- quickly and transientlye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis”
t1“IAA5, IAA19”
e0“Exogenous IAA induced these genes quickly and transiently”
Claim · model-written summary
BL gradually and continuously induced IAA5 and IAA19.
- Taxon
- ArabidopsisArabidopsist1
- Treatment
- exogenous BLe0
- Gene
- IAA5, IAA19t0
- Outcome
- induced theme0
- Direction
- inducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“IAA5, IAA19”
t1“Arabidopsis”
e0“exogenous BL induced them gradually and continuously”
Claim · model-written summary
IAA induced DR5-GUS with kinetics similar to IAA5 and IAA19.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- IAAe0
- Gene
- DR5e0
- Outcome
- GUS (beta-glucuronidase) genee0
- Direction
- inducede0
- Comparator
- IAA5 and IAA19 genese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis”
e0“DR5, a synthetic auxin response element, with the GUS (beta-glucuronidase) gene was induced with similar kinetics to those of the IAA5 and IAA19 genes in response to both IAA and BL treatment of transgenic plants”
Claim · model-written summary
BL induced DR5-GUS with kinetics similar to IAA5 and IAA19.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- BL treatmente0
- Gene
- DR5e0
- Outcome
- GUS (beta-glucuronidase) genee0
- Direction
- inducede0
- Comparator
- IAA5 and IAA19 genese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis”
e0“DR5, a synthetic auxin response element, with the GUS (beta-glucuronidase) gene was induced with similar kinetics to those of the IAA5 and IAA19 genes in response to both IAA and BL treatment of transgenic plants”
Claim · model-written summary
BL did not raise endogenous IAA levels in wild type or det2 seedlings.
- Taxon
- ArabidopsisArabidopsise0
- Material
- wild type (WT) or the BR-deficient mutant det2e0
- Treatment
- BLe0
- Outcome
- Endogenous IAA levels per gram fresh weighte0
- Direction
- did not increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Endogenous IAA levels per gram fresh weight did not increase when seedlings of Arabidopsis wild type (WT) or the BR-deficient mutant det2 were treated with BL”
Claim · model-written summary
det2 had lower IAA transcript levels than wild type.
- Taxon
- ArabidopsisArabidopsist0
- Material
- det2 mutante0
- Outcome
- levels of IAA transcriptse0
- Direction
- lowere0
- Comparator
- WTe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis”
e0“the levels of IAA transcripts were lower in the det2 mutant than in the WT”
Claim · model-written summary
det2 had higher endogenous IAA levels than wild type.
- Taxon
- ArabidopsisArabidopsist0
- Material
- det2 mutante0
- Outcome
- endogenous IAA levels per gram fresh weighte0
- Direction
- highere0
- Comparator
- WTe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis”
e0“endogenous IAA levels per gram fresh weight were higher in the det2 mutant than in the WT”
Claim · model-written summary
BL appears to activate IAA genes partly through an auxin response element.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- BLe0
- Gene
- IAA genese0
- Outcome
- IAA genes are inducede0
- Qualifier
- via the activation of the auxin response elemente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis”
e0“IAA genes are induced by BL, at least in part, via the activation of the auxin response element”
Claim · model-written summary
The authors infer independent BR and auxin activation of IAA and DR5-GUS transcription.
- Taxon
- ArabidopsisArabidopsist0
- Gene
- IAA and DR5-GUS genese0
- Outcome
- transcriptional system of the IAA and DR5-GUS genese0
- Qualifier
- BR and auxin signaling pathways independently activatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis”
e0“BR and auxin signaling pathways independently activate the transcriptional system of the IAA and DR5-GUS genes”
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See all 12 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.