Abstract
Leaves and flowers begin life as outgrowths from the edges of shoot apical meristems. Stem cell divisions in the meristem center replenish cells that are incorporated into organ primordia at the meristem periphery and leave the meristem. Organ boundaries, regions of limited growth that separate forming organs from the meristem, serve to isolate these two domains and are critical for coordination of organogenesis and meristem maintenance. Boundary formation and maintenance are poorly understood processes, despite the identification of a number of boundary-specific transcription factors. Here we provide genetic and biochemical evidence that the Arabidopsis thaliana transcription factor lateral organ boundaries (LOB) negatively regulates accumulation of the plant steroid hormone brassinosteroid (BR) in organ boundaries. We found that ectopic expression of LOB results in reduced BR responses. We identified BAS1, which encodes a BR-inactivating enzyme, as a direct target of LOB transcriptional activation. Loss-of-function lob mutants exhibit organ fusions, and this phenotype is suppressed by expression of BAS1 under the LOB promoter, indicating that BR hyperaccumulation contributes to the lob mutant phenotype. In addition, LOB expression is BR regulated; therefore, LOB and BR form a feedback loop to modulate local BR accumulation in organ boundaries to limit growth in the boundary domain.
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Claims 8
Claim · model-written summary
LOB negatively regulates brassinosteroid accumulation in organ boundaries.
- Taxon
- Arabidopsis thaliana
Arabidopsis thalianae0 - Organ / stage
- organ boundariese0
- Gene
- lateral organ boundaries (LOB)e0
- Compound
- brassinosteroid (BR)e0
- Outcome
- accumulation of the plant steroid hormone brassinosteroid (BR)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the Arabidopsis thaliana transcription factor lateral organ boundaries (LOB) negatively regulates accumulation of the plant steroid hormone brassinosteroid (BR) in organ boundaries”
Claim · model-written summary
Ectopic LOB expression reduces BR responses.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Treatment
- ectopic expression of LOBe0
- Gene
- LOBe0
- Outcome
- BR responsese0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ectopic expression of LOB results in reduced BR responses”
e1“the Arabidopsis thaliana transcription factor lateral organ boundaries (LOB) negatively regulates accumulation of the plant steroid hormone brassinosteroid (BR) in organ boundaries”
Claim · model-written summary
BAS1 is a direct target of LOB transcriptional activation.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Gene
- BAS1e0
- Outcome
- a direct target of LOB transcriptional activatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We identified BAS1, which encodes a BR-inactivating enzyme, as a direct target of LOB transcriptional activation”
e1“the Arabidopsis thaliana transcription factor lateral organ boundaries (LOB) negatively regulates accumulation of the plant steroid hormone brassinosteroid (BR) in organ boundaries”
Claim · model-written summary
Loss-of-function lob mutants show organ fusions.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Material
- lob mutantse0
- Outcome
- organ fusionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Loss-of-function lob mutants exhibit organ fusions”
e1“the Arabidopsis thaliana transcription factor lateral organ boundaries (LOB) negatively regulates accumulation of the plant steroid hormone brassinosteroid (BR) in organ boundaries”
Claim · model-written summary
BAS1 expression under the LOB promoter suppresses organ fusions in lob mutants.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae2
- Material
- lob mutantse1
- Treatment
- expression of BAS1 under the LOB promotere0
- Gene
- BAS1e0
- Outcome
- organ fusionse1
- Direction
- suppressede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“this phenotype is suppressed by expression of BAS1 under the LOB promoter”
e1“Loss-of-function lob mutants exhibit organ fusions”
e2“the Arabidopsis thaliana transcription factor lateral organ boundaries (LOB) negatively regulates accumulation of the plant steroid hormone brassinosteroid (BR) in organ boundaries”
Claim · model-written summary
The suppression suggests BR hyperaccumulation contributes to the lob fusion phenotype.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Compound
- BRe0
- Outcome
- lob mutant phenotypee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“BR hyperaccumulation contributes to the lob mutant phenotype”
e1“the Arabidopsis thaliana transcription factor lateral organ boundaries (LOB) negatively regulates accumulation of the plant steroid hormone brassinosteroid (BR) in organ boundaries”
Claim · model-written summary
LOB expression is regulated by BR.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Gene
- LOBe0
- Compound
- BRe0
- Outcome
- LOB expressione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“LOB expression is BR regulated”
e1“the Arabidopsis thaliana transcription factor lateral organ boundaries (LOB) negatively regulates accumulation of the plant steroid hormone brassinosteroid (BR) in organ boundaries”
Claim · model-written summary
LOB and BR form a feedback loop that modulates local BR accumulation and limits boundary growth.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Gene
- LOBe0
- Compound
- BRe0
- Outcome
- growth in the boundary domaine0
- Qualifier
- feedback loope0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“LOB and BR form a feedback loop to modulate local BR accumulation in organ boundaries to limit growth in the boundary domain”
e1“the Arabidopsis thaliana transcription factor lateral organ boundaries (LOB) negatively regulates accumulation of the plant steroid hormone brassinosteroid (BR) in organ boundaries”
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See all 16 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.