Abstract
Organ initiation requires the specification of a group of founder cells at the flanks of the shoot apical meristem and the creation of a functional boundary that separates the incipient primordia from the remainder of the meristem. Organ development is closely linked to the downregulation of class I KNOTTED1 LIKE HOMEOBOX (KNOX) genes and accumulation of auxin at sites of primordia initiation. Here, we show that Arabidopsis thaliana JAGGED LATERAL ORGANS (JLO), a member of the LATERAL ORGAN BOUNDARY DOMAIN (LBD) gene family, is required for coordinated organ development in shoot and floral meristems. Loss of JLO function results in ectopic expression of the KNOX genes SHOOT MERISTEMLESS and BREVIPEDICELLUS (BP), indicating that JLO acts to restrict KNOX expression. JLO acts in a trimeric protein complex with ASYMMETRIC LEAVES2 (AS2), another LBD protein, and AS1 to suppress BP expression in lateral organs. In addition to its role in KNOX regulation, we identified a role for AS2 in regulating PINFORMED (PIN) expression and auxin transport from embryogenesis onwards together with JLO. We propose that different JLO and AS2 protein complexes, possibly also comprising other LBD proteins, coordinate auxin distribution and meristem function through the regulation of KNOX and PIN expression during Arabidopsis development.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Alleles
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Arabidopsis / anatomy & histology
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Arabidopsis / genetics*
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Arabidopsis / growth & development
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Arabidopsis / metabolism
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Arabidopsis Proteins / genetics
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Arabidopsis Proteins / metabolism*
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Biological Transport
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Down-Regulation
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Gene Dosage
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Gene Expression Regulation, Plant / genetics*
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Indoleacetic Acids / metabolism*
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Meristem / anatomy & histology
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Meristem / genetics
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Meristem / growth & development
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Meristem / metabolism
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Models, Molecular
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Mutation
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Phenotype
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Plant Components, Aerial / anatomy & histology
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Plant Components, Aerial / genetics
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Plant Components, Aerial / growth & development
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Plant Components, Aerial / metabolism
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Plant Roots / anatomy & histology
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Plant Roots / genetics
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Plant Roots / growth & development
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Plant Roots / metabolism
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Protein Interaction Mapping
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Protein Multimerization
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Protein Structure, Tertiary
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Repressor Proteins / genetics
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Repressor Proteins / metabolism*
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Seedlings / anatomy & histology
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Seedlings / genetics
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Seedlings / growth & development
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Seedlings / metabolism
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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Up-Regulation
Substances
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AS2 protein, Arabidopsis
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ASYMMETRIC LEAVES1 protein, Arabidopsis
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Arabidopsis Proteins
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Indoleacetic Acids
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JAGGED LATERAL ORGANS protein, Arabidopsis
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Repressor Proteins
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Transcription Factors