Abstract
Together, auxin and cytokinin regulate many of the processes that are critical to plant growth, development, and environmental responsiveness. We have previously shown that exogenous auxin regulates cytokinin biosynthesis in Arabidopsis thaliana. In this work, we show that, conversely, the application or induced ectopic biosynthesis of cytokinin leads to a rapid increase in auxin biosynthesis in young, developing root and shoot tissues. We also show that reducing endogenous cytokinin levels, either through the induction of CYTOKININ OXIDASE expression or the mutation of one or more of the cytokinin biosynthetic ISOPENTENYLTRANSFERASE genes leads to a reduction in auxin biosynthesis. Cytokinin modifies the abundance of transcripts for several putative auxin biosynthetic genes, suggesting a direct induction of auxin biosynthesis by cytokinin. Our data indicate that cytokinin is essential, not only to maintain basal levels of auxin biosynthesis in developing root and shoot tissues but also for the dynamic regulation of auxin biosynthesis in response to changing developmental or environmental conditions. In combination with our previous work, the data suggest that a homeostatic feedback regulatory loop involving both auxin and cytokinin signaling acts to maintain appropriate auxin and cytokinin concentrations in developing root and shoot tissues.
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Claims 6
Claim · model-written summary
Applied or ectopically synthesized cytokinin rapidly increased auxin biosynthesis in developing roots and shoots.
- Taxon
- Arabidopsis
Arabidopsist0 - Organ / stage
- young, developing root and shoot tissuese0
- Treatment
- application or induced ectopic biosynthesis of cytokinine0
- Outcome
- auxin biosynthesise0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the application or induced ectopic biosynthesis of cytokinin leads to a rapid increase in auxin biosynthesis in young, developing root and shoot tissues.”
t0“Arabidopsis”
Claim · model-written summary
CYTOKININ OXIDASE induction reduced auxin biosynthesis.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- induction of CYTOKININ OXIDASE expressione0
- Gene
- CYTOKININ OXIDASEe0
- Outcome
- auxin biosynthesise0
- Direction
- reductione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reducing endogenous cytokinin levels, either through the induction of CYTOKININ OXIDASE expression or the mutation of one or more of the cytokinin biosynthetic ISOPENTENYLTRANSFERASE genes leads to a reduction in auxin biosynthesis.”
t0“Arabidopsis”
Claim · model-written summary
Mutation of cytokinin biosynthetic ISOPENTENYLTRANSFERASE genes reduced auxin biosynthesis.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- mutation of one or more of the cytokinin biosynthetic ISOPENTENYLTRANSFERASE genese0
- Gene
- ISOPENTENYLTRANSFERASEe0
- Outcome
- auxin biosynthesise0
- Direction
- reductione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“reducing endogenous cytokinin levels, either through the induction of CYTOKININ OXIDASE expression or the mutation of one or more of the cytokinin biosynthetic ISOPENTENYLTRANSFERASE genes leads to a reduction in auxin biosynthesis.”
t0“Arabidopsis”
Claim · model-written summary
Cytokinin changed transcript abundance of putative auxin biosynthetic genes.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- Cytokinine0
- Gene
- putative auxin biosynthetic genese0
- Outcome
- abundance of transcripts for several putative auxin biosynthetic genese0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cytokinin modifies the abundance of transcripts for several putative auxin biosynthetic genes, suggesting a direct induction of auxin biosynthesis by cytokinin.”
t0“Arabidopsis”
Claim · model-written summary
The authors infer that cytokinin maintains basal auxin biosynthesis and dynamically regulates it.
- Taxon
- ArabidopsisArabidopsist0
- Organ / stage
- developing root and shoot tissuese0
- Compound
- cytokinine0
- Outcome
- basal levels of auxin biosynthesise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cytokinin is essential, not only to maintain basal levels of auxin biosynthesis in developing root and shoot tissues but also for the dynamic regulation of auxin biosynthesis in response to changing developmental or environmental conditions.”
t0“Arabidopsis”
Claim · model-written summary
The authors propose a homeostatic feedback loop involving auxin and cytokinin signaling to maintain hormone concentrations.
- Taxon
- ArabidopsisArabidopsist0
- Organ / stage
- developing root and shoot tissuese0
- Outcome
- appropriate auxin and cytokinin concentrationse0
- Qualifier
- homeostatic feedback regulatory loope0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a homeostatic feedback regulatory loop involving both auxin and cytokinin signaling acts to maintain appropriate auxin and cytokinin concentrations in developing root and shoot tissues.”
t0“Arabidopsis”
The same questions in other papers
class · physiology: hormones · ArabidopsisPositive and negative results
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