Function And Expression Pattern Inquiry Of URO,a Auxin Metabolize Regulation Gene In Arabidopsis

The Arabidopsis semi-dominant leaf mutant, upright rosette (uro), was obtained from a T-DNA insertion-population. The seedling of uro have a phenotype of upright-growing rosette leaves, when grown up, it displays pleiotropic phenotypes including loss of apical dominance, interfascicular fiber development anomaly, the number of lateral branch increased, softening and thicking of shoot stem.Our previously results show that the overexpression of URO gene in mutant caused these auxin-related phenotypes, because the gene alter IAA homeostasis throught control the proportion of free and conjugated IAA. It was found that the uro mutant needed less water than wild type. In order to study whether the uro mutant increased drought tolerance than wild-type and how to improve, mutant was observed under drought stress. At the same time, other studies were carried on. The water content of detached shoots and water loss rate was measured. The sensitivity of mutant to exogenous ABA, the development of root and trichome distribution was investigated, and the content of MDA was determination. The preliminary analysis shows that the senescence of uro mutant delayed that was caused enhancing drought tolerance.To further study the functions of URO genes, the analysis of gene expression patterns of URO, we connect gene promoter with GUS reporter, then transgenic wild type Arabidopsis thaliana.It was obtained that the URO gene major expressed in vegetative growth stage. The main function of URO has some connection with the vegetative growth.This study proved that the uro mutant has enhanced drought tolerance than wild type. We have studied the possible drought tolerance mechanism of uro mutant and analysis the URO gene expression pattern. The results indicate that the URO gene may involved in Arabidopsis vegetative development process through free IAA concentration regulation. The overexpression of URO gene in mutant caused an increase in the free IAA concentration. This change can enhance drought tolerance because the enhancement of vegetative growth can delay the senescence of uro mutant.