Triptychon (TRY) Protein Accumulation in the Roots of Mutant Auxinresistant 1 (axr1) Arabidopsis thaliana

Plant root hairs play an essential role in water and nutrient uptake. CAPRICE (CPC) family transcription factors act to induce root hairs in Arabidopsis thaliana. Previously, using a proteasome inhibitor assay, we proposed that the CPC family protein TRIPTYCHON (TRY) was degraded through the ubiquitin/26S proteasome pathway. The Auxin resistant 1 (AXR1) gene encodes the ubiquitin-activating enzyme E1. In this study, to further investigate the mechanism of TRY degradation, we introduced a CPCp:TRY-GFP construct into axr1-3 A. thaliana mutants. The CPCp:TRY-GFP transgenic plant showed weak TRY-GFP fluorescence while the CPCp:TRY-GFP in axr1-3 transgenic plant showed strong TRY-GFP fluorescence. These results support the suggestion that TRY is degraded by the ubiquitin/26S proteasome mechanism.