The vacuole occupies most of the volume of plant cells; thus the tonoplast marker deltaTIP-GFP delineates cell shape, for example, in epidermis. This permits rapid identification of mutants. Using this strategy, we identified the cell shape phenotype 1 (csp-1) mutant in Arabidopsis thaliana. Beyond an absence of lobes in pavement cells, phenotypes included reduced trichome branching, altered leaf serrations and stem branching, and increased stomatal density. This result from a point mutation in AtTPS6 encoding a conserved amino-terminal domain thought to catalyze trehalose-6-phosphate synthesis and a carboxy-terminal phosphatase domain is catalyzing a two-step conversion to trehalose. Expression of AtTPS6 in the yeast mutants tps1 (encoding a synthase domain) and tps2 (synthase and phosphatase domains) indicates that AtTPS6 is an active trehalose synthase. AtTPS6 fully complemented defects in csp-1. Mutations in Class I genes (AtTPS1-4) indicate a role in regulating starch storage, resistance to drought and inflorescence architecture. Class II genes (AtTPS5 - AtTPS11) encode multi-functional enzymes having synthase and phosphatase activites. We show that Class II AtATPS6 regulates plant architecture, the shape of epidermal pavement cells and the branching of trichomes. Thus, beyond a role in development, we demonstrate that the Class II gene AtTPS6 is important for controlling cellular morphogenesis.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|