Arabidopsis Upright Rosette (the Uro) Gene Regulation Of Plant Morphological Structure Built

The Arabidopsis Semi-dominant mutant, upright rosettes (uro), was obtained from a T-DNA insertional mutant library. In comparison to wide-type (WT) plants, the uro mutant displays pleiotropic phenotypes including loss of apical dominance, soft and thickening of shoot stem, altered numbers of petals and stamens and abnormally fused organs. Further ananlyses show that uro mutant has more secondary shoot branching than WT plants, and a delayed vascular differentiation, lacking interfascicular fiber formation in stem.The loss of apical dominance and the defects in vascular development and interfascicular fiber formation suggest that the URO function might be associated with auxin-mediated plant development. We introduced a DR5::GUS construct into the uro background, and observed the altered GUS staining patterns. We also found that free IAA content was reduced obviously in uro mutant by IAA immuno-localization. Furthermore, GH3-likes genes was upregulated distinctly in the uro mutant. We therefore propose that the URO gene may play an important role in the auxin regulatory pathway through regulation of GH3-like genes.The URO gene has been cloned that encodes a C2H2 transcription factor. RT-PCR analysis revealed that URO is expressed in all tissues examined with strong expression in stem. In the uro mutant, URO showed similar gene expression pattern to that of the wild-type, but the transcript levels were apparently enhanced. Overexpression of URO driven by a 35S promoter resulted in transgenic plants staying at the cotyledon stage without further growth. Taken together, our results suggest that URO plays a critical role in IAA-mediated regulation of plant development.