Identification And Preliminary Function Prediction Of PpTOPP4 Gene Family Members

Peach tree is one of the fruit trees with economic importance in China.Due to the vigorous growth of peach trees,frequent pruning or spraying of growth inhibitors is needed to control the growth of peach trees during cultivation,which not only increases the difficulty of orchard management,increases labor costs,but also causes a waste of tree nutrition.In order to reduce the investment of manpower and material resources and reduce the environmental pollution caused by chemical reagents,it is particularly of great significance to cultivate excellent peach varieties which are convenient for tree management.As a result,to make an analysis of the regulation mechanism of internode length of peach branches will be conductive to cultivate new peach varieties which meet the requirements of dwarfing cultivation.What is made a study for the subject is the TOPP4 gene regulating the phosphorylation of peach growth inhibitor protein DELLA.According to the published peach genome,four PpTOPP4 genes were identified in peach genome.The transcription levels of PpTOPP4 in different tissue of Prunus persica 'Qiumihong'(QMH)were analyzed.The function of PpTOPP4 gene family members was verified.The main results of the tests are as follows:1?Analyzing the sequence of PpTOPP4 family members:four peach TOPP4 genes,named PpTOPP4-1,PpTOPP4-2,PpTOPP4-3 and PpTOPP4-4 were identified accoding the published peach genome database.Four PpTOPP4 genes have a CDS region with a length of 1111 bp,1060 bp,1022 bp and 1008 bp.respectively,and encode 316,342,320 and 325 amino acids.Based on multiple sequence alignment,it's found that PpTOPP4 gene family members have a high sequence similarity with 9 TOPPs members in Arabidopsis thaliana.Phylogenetic tree analysis showed that PpTOPP4-1 was closely clustered with AtTOPP4.2?Analyzing the tissue-specific expression pattern and the subcellular localization of PpTOPP4 gene:it was analyzed that the transcription levels of PpTOPP4 genes in different tissues of QMH,including peach flower,fruit,upper stem,middle stem,lower stem,leaf and peach kernel were detected respectively.The results showed that the four members of the PpTOPP4 gene family had transcripts in each of the tested tissues,and all of them had the highest transcription level in flowers of QMH.PpTOPP4-1 and PpTOPP4-2 have very similar expression patterns in multiple tissues.The expression vector of PpTOPP4-1-GFP,PpTOPP4-3-GFP and PpTOPP4-4-GFP was constructed by homologous recombination,and the tobacco was injected with Agrobacterium tumefaciens containg the four expression vector.The green fluorescent was detected using laser confocal microscope and showed that all members of the PpTOPP4 gene family were co-expressed in the nuclear membrane.3?Functional verification of PpTOPP4 gene family members:over-expression of three TOPP4 genes in Arabidopsis thaliana by agrobacterium tumefaciens dipping method.It's showed based on the results that the height of transgenic lines overexpressing PpTOPP4-1 and PpTOPP4-4 at 18 days was significantly shorter than that of wild type,and transgenic lines overexpressing4-3 was significantly higher than that of wild type.At 45 days,there was no significant difference in plant height between the three over-expressed lines and the wild type.With the basis of the above results,we believe that PpTOPP4-1,PpTOPP4-3 and PpTOPP4-4 can affect the bolting time of Arabidopsis thaliana and then affect the plant height at the early development stage of Arabidopsis,while there is no significant effect on the final height of Arabidopsis.