Isolation And Mobility Analysis Of NAC Gene Family In Japanese Apricot

As an important horticultural technology,grafting technology is widely used in seedling raising and high grafting of fruit trees.The interaction between rootstock and scion is not only related to hormone and nutrient transport,but also to the long-distance transport of macromolecules such as mRNA.It has been proved that RNA can be used as a systematic signal molecule for long-distance transport through grafting,thus regulating gene expression and affecting plant growth and development.In this study,the NAC gene family of Prunus mume was identified by bioinformatics,and its tissue-specific expression was analyzed by real-time fluorescence quantitative PCR.Then,the PmNAC32 gene was isolated from Prunus mume cultivar ’Longyan’;PmNAC32 overexpressing tobacco lines were constructed and grafted with wild-type tobacco to study the long-distance transmission characteristics of PmNAC32 gene mRNA and its regulatory role.The main findings are as follows:1.Bioinformatics analysis showed that there were 106 members of NAC gene family in Prunus mume genome,which were divided into 12 subgroups according to their phylogenetic characteristics.Most of the PmNAC genes encode acidic amino acids,and most of the NAC proteins are hydrophilic proteins.The secondary structure of the protein is mainly composed of irregular curl.Subcellular localization prediction showed that NAC protein was a typical nuclear protein.Tissue expression analysis showed that NAC genes were expressed in different tissues,and the differences in expression characteristics indicated that they might have many different biological functions.2.PmNAC32 gene was isolated from ’Longyan’,and its structure and function were analyzed by bioinformatics method.The results showed that the full-length CDS of PmNAC32 gene was 969 bp,encoding 322 amino acids.The protein was stable,hydrophilic and non-secretory.There was no transmembrane movement in the cell,and random curl was used as the main component of the protein.The PmNAC32 protein N-terminal contains a conserved NAM domain,which is a typical NAC protein.Phylogenetic analysis showed that PmNAC32 protein was most closely related to peach NAC and might have similar functions.3.The over-expression vector of PmNAC32 gene was constructed and transformed into tobacco by Agrobacterium tumefaciens,and the transgenic lines of PmNAC32 were obtained.The over-expression of PmNAC32 could make tobacco blossoms early and accelerate the aging rate of leaves.The grafting of transgenic tobacco and wild type tobacco showed that the scion PmNAC32 mRNA could be transferred to rootstock and the rootstock PmNAC32 mRNA could be transferred to scion,indicating that PmNAC32 mRNA had two-way long-distance transmission in transgenic tobacco grafting system.In addition,the grafting of transgenic tobacco as rootstock could advance the flowering stage and premature senescence of leaves of wild-type scion,which further verified that PmNAC32 mRNA could be transferred from rootstock to scion by grafting,thus regulating scion characters.