Overexpression Of Arabidopsis URO Gene Leads To Secondary Cell Wall Development Retarded And Resist To Abiotic Stress

The Arabidopsis UPRIGHT ROSETTE (URO) gene encodes a single C2H2zinc finger protein,belongs to the plant specific transcriptional factor. Overexpression of it reveals a homeostatic control for indole-3-acetic acid (IAA), In addition, its gain-of-function mutant uro displays pleiotropic phenotypes including loss of apical dominance, softening and thicking of shoot stem, interfascicular fiber development anomaly, resistence to dehydration and vegetative growth prolong.Our results indicate that overexpression of the URO gene inhibits the secondary cell wall development, URO-overexpress transgnic plants and uro mutant exhibit retarded secondary xylem fiber and interfiber cells. moreover, the vessel cells show weak fluorescence light, and smaller cells than wild type (ler). Molecular analysis show that URO gene acts as a upstream transcription factor to inhibit entire secondary cell wall transcription network genes and cellulose and lignin synthesis genes.Our studies have shown that uro mutant can resist drought and NaCl stress.To further uncover the mechanisms underlying abiotic tolerence of uro mutant, we investigate the URO expression under ABA and Mannitol. ABA and Mannitol inbibit the URO gene expression.This indicates that URO pathway is mutual antagonism of the ABA pathway. In addtion, uro mutant are not tolerant to oxidative stress. Moerover, uro mutant displays enhancement of vegetative growth and delaying the senescence. Together, these results demonstrate that overexpression of URO gene make uro mutant resist to drought by delaying the plant senescence mediated by ABA.We generated transgenic Arabidopsis plants with URO and its homolog genes under pYAB3promotor to illustrate gene function redundcy, we have obtained the T1transgnic plants, further studies will be investigated for their function.