The Cloning And Analysis Of Wax Metabolism Related Gene During Storage Of Blueberry

Blueberry(Ericaceae,Vaccinium spp.)is perennial shrub fruit tree.Blueberry fruit is not resistant to storage and its harvest period is short,resulting in limited commercial value.Wax is one of the structures of the cuticle on terrestrial plants’ outer epidermis.Wax will change differently with different storage conditions on postharvest fruit.At the same time,wax has an impact on the quality of fruit,including the apparent integrity,water loss,softening and resistance to pests and diseases.Therefore,wax is an important factor that cannot be ignored during fruit postharvest storage.In order to prevent the quality deterioration of blueberry fruit during postharvest storage,the quality changes and wax changes of wax-rich ’Brightwell’ as well as wax-poor ’Legacy’fruits during storage at 25 °C and relative humidity 80 % were studied.The wax composition and related gene changes during storage were analyzed by transcriptome and GC-MS technique.Besides,the full-length cloning and functional analysis of the selected genes were carried out.The main results are as follows :(1)’Brightwell’ and ’Legacy’ were stored at 25 °C and 80 % relative humidity for8 days to study their physiological changes as well as changes in epidermal wax structure and composition.The results showed that the water loss rate and decay rate of’Brightwell’ fruit were significantly lower than those of ’Legacy’,TSS,TA and wax morphological integrity were higher than those of ’Legacy’,and there was no significant difference in hardness.The difference in water loss rate between two varieties during storage may be related to the content of terpenoids.The content of alkanes and esters was significantly negatively correlated with the decay rate,the content of ketones was significantly negatively correlated with TA and TSS,and the content of esters and aldehydes was significantly positively correlated with TSS.It is speculated that high humidity is the reason why the wax morphology of ’Brightwell’ and ’Legacy’ changed from complete to incomplete during storage.The difference in aldehydes and ketones between two varieties is the main reason for the difference in wax morphology between the varieties.(2)The DEGs of two varieties during storage were screened by transcriptome technology.The GO enrichment analysis of DEGs showed that the number of DEGs related to β-amyrin synthase in ’Brightwell’ was higher than that in ’Legacy’ during storage.In the KEGG enrichment analysis of DEGs,the wax-related metabolic pathways involved in the storage process of two varieties were glyceride metabolic pathways,and the pathways enriched in the variety differences were linoleic acid metabolism as well as fatty acid degradation and extension.In the correlation network between DEMs and DEGs,for the top ten DEMs of | log10 Foldchange |,DEGs during storage and DEGs of variety differences mainly played a negative regulatory role.(3)Screening and studying the DEGs that react on the main components of blueberry wax in transcriptome,four full-length CDS were cloned: VcKCS6,VcKCS10,Vc CYP716A340 and Vc CYP716A403.Bioinformatics,spatiotemporal expression pattern and subcellular localization analysis of these four genes were carried out.The results showed that VcKCS6 and VcKCS10 were located in the cytoplasm,VcKCS6 was related to Dl KCS6(Diospyros lotus),and VcKCS10 was an independent evolutionary branch of KCS family.VcKCS6 was mainly expressed in blueberry roots and fruit epidermis at S2 stage,and VcKCS10 was mainly expressed in fruit epidermis at S5 stage.It was speculated that two gene products were related to the synthesis of VLCFAs in cells at this stage.Vc CYP716A340 and Vc CYP716A403 are located in the endoplasmic reticulum.Vc CYP716A403 is closely related to MICYP716A80(Maesa lanceolata).Vc CYP716A340 is an independent evolutionary branch of the CYP716 A subfamily.Vc CYP716A340 was mainly expressed in the roots of blueberry and the fruit epidermis of S4 period,while Vc CYP716A403 was mainly expressed in the fruit epidermis of S4 period,which was speculated to be related to the synthesis of ursolic acid and oleanolic acid in the cells of this period.