The Preliminary Study On The Function Of AtPUB9 In Arabidopsis

The ubiquitination is one of the important mechanisms of posttranscriptional modification for eukaryotic proteins.The specificity of substrate s in the ubiquitination is determined by ubiquitin ligase,which is important for plants enduring the biotic and abiotic stresses.In order to explore the function of AtPUB9 in Arabidopsis,we analyzed the role of AtPUB9 in the seed germination and seedling growth,via ABA-inhibited process of Arabidopsis.The main results are summarized as follows:1.The lost-of-function mutant of AtPUB9,pub9 mutant,did not show obvious phenotype under normal growth conditions.However,when treated with ABA,the seed germination and seedling growth of pub9 mutants are remarkably different from those of the wild-type(WT),such as,increased ABA-sensitivity was scored with the pub9 mutants.2.Overexpression(OE)of AtPUB9,could enhance the resistence of ABA,descreased ABA-sensitivity showed in the seed germination and seedling growth of plants of OE lines.3.Other than the stage of seed germination and seedling growth,there were not significant differences in the adult plant development,when compared the OE lines with the WT plants.4.The expression patterns of AtPUB9 in Arabidopsis tissues were analyzed.Combined with the q RT-PCR,it was observed that the highest expression level of PUB9 was detected in the young seedlings.Localizations of cytoplasm and the nucleus were observed by analyzing the expressions of PUB9-YFP.5.The 5-day seedlings were treated with different hormones and abiotic stress,respectively,and GUS staining and q RT-PCR detection showed that the expression of AtPUB9 was enhanced by ABA,Na Cl and mannitol.6.Under the conditions of high salinity and osmosis,the seed germination and the elongation of roots of 5-day-old seedlings were significantly inhibited.However,these stress conditions did not have much effect to the growth of OE lines.