Expression Analysis And Functional Exploration Of PpNAC56 And PpNAC72 Related To Peach Fruit Maturity Date

Peach belongs to the family Rosaceae,genus Prunus and is one of important economic fruit tree in China.Due to the putrescibility and poor storability of peach fruit,the supply time in every year is very short..Breeding cultivars with different maturity date will lengthen the supply time of peach fruit effectively.Therefore,the maturity date of peach fruit is an improtant economic trait and one of the important targets of breeding.It is great significant for breeding by genetic transformation to research the gene regulating the mature date of peach fruit and peach marker-assisted breeding.(1)To verify 11 molecular marker related to maturity date of peach fruit,199 peach cultivars were collected.Among the 11 markers,only NAC72-Indel marker could well distinguish extremely early and late maturity varieties.It means that Pp NAC72 could to be a candistage gene associated with peach maturity date.(2)Two NAC genes(Pp NAC72 and Pp NAC56)with a spacer sequence of 19,863 bp was identified in peach NAC72-Indel locus.In addition,NOR locus in tomato and ETHQV6.3 locus in melon,related to fruit maturity,also contain two NAC genes which are highly homologous to Pp NAC72 and Pp NAC56,respectively.It means that two tandem genes,Pp NAC72 and Pp NAC56,may be conserved mechanism regulating maturity date of peach fruit.(3)The coding sequences of Pp NAC72 and Pp NAC56 were cloned and sequencing.There no difference between Pp NAC56 and reference sequence;two trancripts of Pp NAC72 were identified.One(Pp NAC72m)of the transcripts has a 9 bp insertion compared with reference genome sequence.The transcript levels of Pp NAC72 and Pp NAC56 were analyzed in three cultivars with different maturity stage.The results showed that the highest transcript level of Pp NAC72 gene was detected during the stage close to fruit maturity in three cultivars.Pp NAC56 always keeps a higher transcript level compared with Pp NAC72.It suggested that Pp NAC72 regulates the fruit maturity of peach directly.(4)The autoactivition of Pp NAC56,Pp NAC72 and Pp NAC72 m and the protein interaction between the three NACs have been analyzed.The three NAC transcription factors have been discovered the transcriptional activation activity,so should find the transcriptional activation domain of Pp NAC72 and Pp NAC56 before carried out the interactions between protein experiment.There is a need for further test and verification of whether there is any interaction between Pp NAC72 and Pp NAC56.(5)Build the over-expression vector of Pp NAC72,Pp NAC72 m and Pp NAC56 and three vectors wered transfromed into tomato ‘A57'cotyledon and hypocotyl using the method of agrobacterium mediated.Although no transgenic lines have been sreened now but which also laid the foundation of further studying gene functions of three NAC transcription factors.