Abstract:Caragana intermedia is an important sandfixing shrub in northwest arid area with drought, cold and salinealkali resistance. Excellent stress resistant candidate genes screened from it could provide good gene resources for genetic engineering of forest and forage species. In this study, the full length cDNA sequence of CiPUB22 (plant Ubox 22) had been mined from the transcriptome library constructed in our laboratory using drought stressed seedlings of C. intermedia. The CiPUB22 gene contained 1 260 bp open reading frame (ORF) which encoding 419 amino acids. Quantitative real time PCR analysis showed that the expression levels of CiPUB22 were significantly increased and reached the highest level, which was 12, 35 and 7 times of the control at 1 h after dehydration, NaCl and ABA treatments, respectively. After drought treatment, the relative expression of CiPUB22 was significantly increased and reached the highest level at 12 d, which was 2.5 times more than that of the control. The results indicated that the transcription of CiPUB22 was induced by abiotic stress. Furthermore, expression vector pCanGCiPUB22 was constructed and transformed into the wildtype Arabidopsis. Homozygous transgenic Arabidopsis overexpressing CiPUB22 were generated for further analysis. Seed germination assay showed that CiPUB22 transgenic lines germinated slower than that of wildtype on medium containing 150 mmol/L NaCl, 400 mmol/L mannitol or 1 μmol/L ABA. These results indicated that CiPUB22 decreased tolerance of the transgenic Arabidopsis to salt and osmotic treatments during seed germination.