Bioinformatics And Expression Analysis In Dormancy Of WRKY Transcription Factor In Peach

The dormancy is an important state for perennial behaviour in which meristem activity ceased and insensitive to growth-promoting signals. At present, the research on the dormancy mechanism has been studied in the field of multiple species.The WRKY family as one of the10 largest families of transcription factors predominant exits in plant is considered as plant-specific and plays crucial roles in regulation of plant growth and development. Existing research shows that part of the WRKY transcription factors associated with dormancy.In our study, based on the recently released peach whole-genome sequences we identified 60 candidate WRKY genes. Compared with these in Arabidopsis, the putative genes were classified into three groups, group â…¡ was further divided into five subgroups. Their chromosomal location and gene structure were analyzed, too. Phylogenetic analysis demonstrated the relationship and evolution between peach and Arabidopsis. Finally, we had an elaborate analysis of the expression of the WRKY transcription factors in dormancy. In addition, we validated several WRKY genes are associated with dormancy.The main results are divided into the following five aspects:1. To identify the WRKY family in peach, two different approaches were performed.Finally, 60 non-redundant putative WRKY genes in total were identified in peach compared to75 genes in Arabidopsis genome. The size, molecular weight and isoeletric point of the WRKY genes vary from each other.Ppb022557 m molecular weight is 82187.8 D and ppa026260 m molecular weight is 9048.56;The isoelectric point ranged from 4.7326 to12.2608.2. To evaluate the phylogenetic relationship of the WRKY gene in peach and classify them within the established subfamilies, a total of 134 amino acid sequences of the WRKY domain including 60 sequences from peach and 73 sequences from Arabidopsis were investigated. Based on the phylogenetic tree, the WRKY genes in peach were divided intothree groups(Pp WRKYâ… , Pp WRKYâ…¡, Pp WRKYâ…¢) as those in Arabidopsis. Pp WRKYâ…¡was further classified into five subgroups(Pp WRKYâ…¡a,Pp WRKYâ…¡b,Pp WRKYâ…¡c,Pp WRKYâ…¡d, Pp WRKYâ…¡e). Pp WRKYâ…¡ was the largest group among three groups.3. The WRKY genes are uneven distributed throughout all 8 chromosomes and have no relationship with the length of chromosomes in peach.Chr6 includes the maximum number of the WRKY genes(thirteen genes accounting for 21.3% of the total)followed by Chr1 contains11 genes,whereas Chr7 includes the minimum number(one gene).Based on the exact position of the WRKY genes on peach chromosomes 1 to 8,from top to bottom and the classification of the transcription factors, the nomenclature of Pp WRKYs was finished.Finally, according to the WRKY transcription factors in the chromosome location and grouping of naming, namely Pp WRKY1 to Pp WRKY60.4. In this study,56 genes were analysed. It is obvious that most of the genes in the WRKY family of peach posses intron according to phylogenetic relationship with gene families. In total, the gene structures were consistent with the phylogenetic tree. Numerous gene structures have relationship with the classification especially in group â…¡e and â…¡d, most genes in them only have CDS sequence,without introns and UTR region.5. In this study,34 genes were choosed for q RT-PCR, which distribute in every group.We used eight stages during dormancy to analyse the expression of putative WRKY genes.The results reveal the expression of the genes varied from each other.Pp WRKY59 expression quantity is relatively low, suggests that endodormancy may have some effect;Pp WRKY9,Pp WRKY12, Pp WRKY23, Pp WRKY24, Pp WRKY48, Pp WRKY49, Pp WRKY51, Pp WRKY55 expression quantity is relatively high, and the expression quantity is relatively low in ecodormancy, speculated that it may be associated with the dormancy.