1. Arabidopsis Class I KNOTTED-Like Homeobox Proteins Act Downstream in the IDA-HAE/HSL2 Floral Abscission Signaling Pathway
- Author
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Grethe-Elisabeth Stenvik, Ane Kjersti Vie, Marcel C.G. Proveniers, Reidunn B. Aalen, Atle M. Bones, Véronique Pautot, Melinka A. Butenko, Chun-Lin Shi, Department of Molecular Biosciences [Oslo], Faculty of Mathematics and Natural Sciences [Oslo], University of Oslo (UiO)-University of Oslo (UiO), Department of Biology [Trondheim], Norwegian University of Science and Technology [Trondheim] (NTNU), Institut Jean-Pierre Bourgin (IJPB), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Dept Biol, Fac Sci, Utrecht University [Utrecht], Research Council of Norway [175238/S10, 178049], Department of Biology [Trondheim] (IBI NTNU), and Norwegian University of Science and Technology (NTNU)-Norwegian University of Science and Technology (NTNU)
- Subjects
0106 biological sciences ,EXPRESSION ,[SDV.SA]Life Sciences [q-bio]/Agricultural sciences ,MAP Kinase Signaling System ,Recombinant Fusion Proteins ,Mutant ,Arabidopsis ,Plant Science ,Flowers ,Protein Serine-Threonine Kinases ,01 natural sciences ,03 medical and health sciences ,INFLORESCENCE-DEFICIENT ,Abscission ,LEAF ,CELL-SEPARATION PROCESSES ,Gene Expression Regulation, Plant ,Arabidopsis thaliana ,PLANTS ,Promoter Regions, Genetic ,Research Articles ,030304 developmental biology ,ORGAN ABSCISSION ,Genetics ,Regulation of gene expression ,Homeodomain Proteins ,0303 health sciences ,biology ,THALIANA ,Arabidopsis Proteins ,Genetic Complementation Test ,fungi ,food and beverages ,Cell Biology ,biology.organism_classification ,Floral organ abscission ,Plants, Genetically Modified ,Cell biology ,Phenotype ,GENE BREVIPEDICELLUS ,Mutation ,Homeobox ,RECEPTOR KINASE ,Signal transduction ,KNOX HOMEODOMAIN ,010606 plant biology & botany ,Transcription Factors - Abstract
Floral organ abscission in Arabidopsis thaliana is regulated by the putative ligand-receptor system comprising the signaling peptide INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) and the two receptor-like kinases HAESA and HAESA-LIKE2. The IDA signaling pathway presumably activates a MITOGEN-ACTIVATED PROTEIN KINASE (MAPK) cascade to induce separation between abscission zone (AZ) cells. Misexpression of IDA effectuates precocious floral abscission and ectopic cell separation in latent AZ cell regions, which suggests that negative regulators are in place to prevent unrestricted and untimely AZ cell separation. Through a screen for mutations that restore floral organ abscission in ida mutants, we identified three new mutant alleles of the KNOTTED-LIKE HOMEOBOX gene BREVIPEDICELLUS (BP)/KNOTTED-LIKE FROM ARABIDOPSIS THALIANA1 (KNAT1). Here, we show that bp mutants, in addition to shedding their floral organs prematurely, have phenotypic commonalities with plants misexpressing IDA, such as enlarged AZ cells. We propose that BP/KNAT1 inhibits floral organ cell separation by restricting AZ cell size and number and put forward a model whereby IDA signaling suppresses BP/KNAT1, which in turn allows KNAT2 and KNAT6 to induce floral organ abscission.
- Published
- 2011
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