title: ATH1 and KNAT2 proteins act together in regulation of plant inflorescence architecture.
abstract: The inflorescence of flowering plants is a highly organized structure, not only contributing to plant reproductive processes, but also constituting an important part of the entire plant morphology. Previous studies have revealed that the class-I KNOTTED1-like homeobox (KNOX) genes BREVIPEDICELLUS (BP or KNAT1), KNAT2, and KNAT6 play essential roles in inflorescence architecture. Pedicel morphology is known to contribute greatly to inflorescence architecture, and BP negatively regulates KNAT2 and KNAT6 to ensure that pedicels have a normal upward-pointing orientation. These findings indicate that a genetic network exists in controlling pedicel orientation, but how this network functions in the developmental process remains elusive. Here it is reported that the ARABIDOPSIS THALIANA HOMEOBOX GENE1 (ATH1) gene, which belongs to the BELL1-like homeodomain gene family, is a new member participating in regulating pedicel orientation in the class-I KNOX network. In a genetic screening for suppressors of isoginchaku-2D, a gain-of-function ASYMMETRIC LEAVES2 mutant that displays downward-pointing pedicels, a suppressor mutant was obtained. Characterization of this mutant revealed that the mutation corresponds to ATH1. Genetic analysis indicated that ATH1 acts mainly in the KNAT2 pathway. Yeast two-hybrid and bimolecular fluorescence complementation assays demonstrated that ATH1 physically interacts with KNAT2. The data indicate that the ATH1-KNAT2 complex acts redundantly with KNAT6, both of which are negatively regulated by BP during pedicel development.
authors.affiliation: National Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Limin
authors.initials: L
authors.lastname: Pi
authors.forename: Hai
authors.initials: H
authors.lastname: Huang
authors.forename: Lin
authors.initials: L
authors.lastname: Xu
mesh_terms: D017360:Arabidopsis / Q000033:anatomy & histology* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D056626:Inflorescence / Q000033:anatomy & histology* / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D018398:Homeodomain Proteins; C092213:KNAT2 protein, Arabidopsis; C092852:KNAT5 protein, Arabidopsis; C491111:KNAT6 protein, Arabidopsis; D014157:Transcription Factors