Study On Function And Expression Profiles Of WRKY Transcription Factor In Carica Papaya L

Plants have multiple mechansims to adopt abiotic and biotic stresses in their natural habitat. In the research of the reaction between plant and environment, the regulation of transcriptional level in palnt gene have been paid more and more attention.The study on transcription factor (TF) have been a key point in the research of plant gene.WRKY transcription factor plays a very significant role in the plant to respond various of abiotic and biotic stresses. We need to segregate different WRKY transcription factors and identify their fuction in plant,which is a significant pathway to explain the mechanism of plant resisting stress.In this study,we identified45putative amonia sequence of Carica Papaya WRKY transcription factor in the SUPERFAMILY database,then we built a local papaya databases, data of which come from genebank database.We found45coding sequence(CDS) of Carica Papaya WRKY transcription factor by using tblastn. We used real-time PCR to detect the gene expression levels after stess inducing. According to the result of expression profiles of13Carica Papaya WRKY transcription factors,we chose one WRKY gene to analyse its fucnion,which has a great variation at expression levels. The main results as followed:l.In Carica Papaya we found45WRKY transcription factors and their putative coding sequence.There are56significant WRKY domains in50proteins founded in the SUPERFAMILY database.We identify45WRKY transcription factors and their putative amonia sequence after homology analysis and eliminating redundancy.Then45putative coding sequence of Carica Papaya WRKY transcription factor were identified by using tblastn tool in the Carica Papaya genome.2.After the stess induction of salicylic acid(SA),low temperature,drought,wound and pathogeny,we get the expression profiles of13Carica Papaya WRKY transcription factor gene.By using Real-time PCR,we analyse the transcriptional levles of13WRKY gene to detect the gene expression diversity.The result shows that most of13Carica Papaya WRKY transcription factor are induced by adopt abiotic or biotic stresses except TF1.102, otherwise TF12.199, TF807.3and TF9.35are induced by both. The result shows that most of13Carica Papaya WRKY transcription factor play a positive role in response to abiotic and biotic stresses.3. The full-length cDNA of TF807.3were cloned successfully.In the result of expression profiles of Carica Papaya WRKY transcription factor,we choose one WRKY gene to clone it,which has a great variation at expression levels.By using RT-PCR,we get one558bp gene,which have one WRKY motif.We identify its protein conservative structural domain and make sure that it is one of Carica Papaya WRKY family,callde TF807.3.4.We carried out the agrobacterium transient expression expriment in papaya.The TF807.3is transient over-expression and the expression levels of pathogenesis-related gene SGT1and RAR1are up-regulation.The agrobacterium contained the plant over-expression vector pCAMBIA3300-TF807.3was injected into cotyledons.After3days the the expression levels of pathogenesis-related gene SGT1and RAR1were deteced by real-time PCR.The result showed that SGT1and RAR1were up-regulation by2.4times and4.5times respectively. This suggested that TF807.3plays a role in response to SGT1å'ŒRAR1related resistance pathway.