Cloning Of Three SnRK Genes And Genetic Transformation Of Poplar

SNF1-related protein kinase(SnRK) is a Serine / threonine protein kinase. SnRK genes are capable of mediating signals initiated during drought , salt and cold stress, play important roles in transducing stress signals,increasing protein synthesization and regulating signal transduction. Using the poplar genome database,we cloned three SnRK genes in poplar, and compeleted the transformation of poplar. It would be useful for the development of the gene engineering in genetic improvement of poplar to clone SnRK genes in poplar and develop transgenic polpar.The main conclusions of this study were as following:1 Three SnRK genes were cloned from Populus trichocarpa,designated as PtSnRK-1 ,PtSnRK-2 and PtSnRK-3 respectively. Bioinformatics analysis of PtSnRK genes showed that the ORF of PtSnRK-1 was 1356bp and encoded for a polypeptide of 451 amino acids, 50.22KD molecular weight. The ORF of PtSnRK-2 was 1329bp and encoded for a polypeptide of 442 amino acids, 49.22KD molecular weight. The ORF of PtSnRK-3 was 1320bp and encoded for a polypeptide of 439 amino acids, 48.89KD molecular weight. All of the three PtSnRK genes had conserved protein kinase domain and NAF domain.2 Overexpression vectors pH35GS::PtSnRK-1,pH35GS::PtSnRK-2 and pH35GS: PtSnRK-3 were constructed using gateway cloning technology,and then transfered the three genes into Populus×euramericana cv.'Nanlin895'and Populus tremula×P. tremuloides Michx-clone T89 respectively mediated by Agrobacterium tumefaciems. Transgenic poplars were selected to survive on the culture medium with antibiotics,which includes Populus×euramericana cv.'Nanlin895'and Populus tremula×P. tremuloides Michx-clone T89 with single PtSnRK-1,PtSnRK-2 and PtSnRK-3 gene. The molecular biological tests and plant physiological analysis were carried out to verify these transgenic poplars.3 The three genes had been integrated into poplar genome and could express excessively,which verified by PCR and real time RT-PCR. The result of physiological analysis such as chloroplast content,SOD activity MDA content and leaf relative water content indicated that the drought-resistance and salt-resistance ability of transgenic poplars with PtSnRK genes were extremely enhanced.