Responsed Of WRKY Transcription Factor In Green Peach Aphid Feeding Of Peach RM3 [Prunus Persica Var.densa]

The green peach aphid(GPA)(Myzus persicae Sülzer),one of the most serious pests of peach,is capable of feeding on young leaves and fruits.Aphid feeding causes leafs curling,reduced leafs photosynthesis and fruit quality.Spraying insecticides is the primary method of controlling GPAs in peach orchards.In recent years,continuous use of insecticides has led to resistance to most classes of insecticides,which makes aphid control more difficult.WRKYs are one of the largest transcription factor families(TFs)in higher plants.The WRKY transcription factors have been extensively studied in response to biotic and abiotic stresses.Previous studies performed by our research group have suggested that some WRKY genes in aphid-resistant peach Rm3 response to aphid feeding.However,it is still unclear the specific role of WRKY transcription factors in peach Rm3 response to aphid feeding.Transcriptome analyses showed that twenty-two WRKY genes were differently expressed between the aphid-resistant peach ‘07-15-36' and aphid-susceptible peach ‘07-15-38' with aphid feeding at different time points(0 h,3 h,6 h,9 h,12 h,24 h,48 h and 72 h).In this study,six WRKYs(PpWRKY8,11,12,13,25 and 31)which were significantly up-regulated in aphid-resistant peach ‘07-15-36' with aphid feeding were selected from twenty-two WRKY genes.In this study,six differentially expressed genes,PpWRKY8,11,12,13,25 and 31,were selected to identify the role of WRKYs in the formation of Rm3 aphid resistant pathway through subcellular localization and Arabidopsis genetic transformation.The main results of this study are as follows:1.In this study,1714 genes were differently expressed in aphid-resistant peach ‘07-15-36' and aphid-susceptible peach ‘07-15-38' with aphid feeding.The results of Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis showed that the DEGs were enriched in MAPK signaling pathway,plant pathogen interaction pathway,terpene synthesis pathway,secondary metabolite synthesis pathway and flavonoid synthesis pathway.WRKY transcription factor plays an important role downstream of the pathway in the plant pathogen-pathogen interaction pathway,and participates in the plant disease resistance response by directly regulating the expression of some resistance-related genes.A total of 86 differential genes were enriched in terpenoid and flavonoid synthesis pathways,among them 54 genes had W-Box in their promoter regions.2.We found that PpWRKY8 has two WRKY domains with a zinc finger motif of C2H2,and belongs to the group I WRKY transcription factor.PpWRKY11,12,13,25 and 31 all contained a highly conserved WRKY domain and a C2HC-type zinc finger structure,which belong to group II WRKY transcription factors.Promoter cis-acting elements prediction indentified several elements responsive to light,phytohormone,abiotic and biotic stresses.It can be speculated that WRKY transcription factors play a very important role in the response of peach to various abiotic and biotic stresses.3.Subcellular localization showed that PpWRKY8,11,12,13,25 and 31 were mainly localized in the nucleus.Plant overexpression vectors pCAMBIA3301-PpWRKY8,11,12,13,25 and 31 were constructed and transformed into a wild-type Arabidopsis by Agrobacterium-mediated leaf disc transformation.In this study,transgenic Arabidopsis lines were confirmed by PCR,indicating that the WRKY genes were integrated into Arabidopsis genome.Five transgenic lines were obtained from PpWRKY12,three from PpWRKY8,nine from PpWRKY31,one from PpWRKY25,five from PpWRKY11,and five from PpWRKY13.