| The plant bZIP transcription factor（TF）genes are widely involved in abiotic stress responses,such as salt,cold,drought and low energy stresses.A total of 96 bZIP TFs were identified in the poplar genome by bioinformatic analysis.According to their gene structure,these bZIP TFs could be grouped into 12 subclades,including A to S subfamilies.The expression patterns under salt stress for the S subfamily were analyzed by q RT-PCR.The data clearly reveled that some members in the S subfamily showed response to salt stress.Therefore,we selected one member in the S subfamily for further anlaysis.The gene ID for this member is Potri.002G196200 which is corresponding to AtbZIP 53 in Arabidopsis thaniala.With homology cloing strategy,the DNA sequence of bZIP53 was obtained from poplar cv.Nanlin895.There is no intron in poplar bZIP53 gene and its conding DNA sequence（CDS）is 435bp that encodes 145 amino acid.When comparing the protein sequence of bZIP53 from poplar cv.Nanlin895 with the reference genome and A.thaliana genome,the similarities are 97%and 80%,respectively.The evolutionary analysis showed that poplar bZIP53 tends to cluster with AtbZIP53.Accrding to above analyses,poplar bZIP53 would have similar functions with AtbZIP53.To further characterization of poplar bZIP53,the expression profiles of this genes were investigated under different types of abiotic stresses.Our data clearly revevled that poplar bZIP53 strongly responed to low energy and salt stress induction.However,this genes didn`t show response to ABA treatment.To further characterization of poplar bZIP53,overexpression（OE）transgenic lines were produced for A.thaliana.Totally,two homozygous T3 generation lines with OE poplar bZIP53 for A.thaliana were obtained.With phenotyping assay,the 3 OE T3lines showed reduced seed germination rate and increased salt tolerance when coparing with wild type（WT）.In poplar,OE and IE lines were generated for poplar cv.Nanlin895 and Shanxinyang,respectively.The cuttings of Nanlin895 OE lines showed reduced ability of adventitious rooting comparing with the WT in the normal growth condition（the cuttings were cultured in woody plant medium）.Meanwhile the cuttings of Shanxinyang IE lines also showed reduced ability of adventitious rooting comparing with the WT in the induced growth condition（the cuttings were cultured in woody plant medium containging a given concentration of estradiol）.These results might indicate that the bZIP53transcription factors were involved in salt tolerance and adventitious rootting regulation.In conclusion,we were able to produce some plant materials for further functional characterization of the poplar bZIP transcription factors.Our results also indicated that the bZIP53 transcription factor was a key regulator for poplar salt tolerance and adventitious rootting regulation. |
