Study On Quality Formation And Anthocyanin Metabolism Of Blueberry (Vaccinium Corymbosum L.) Fruit

The introduction of blueberries in Fujian Province for many years,the cultivation area is also widely distributed.In this experiment,the South American highbush blueberry 'FLS03' introduced to Xiamen was studied to analyze.In this study,the quality-related,antioxidant enzyme activities and key enzyme activities of anthocyanin synthesis in blueberry fruit ripening were determined.The correlation between total anthocyanins and other physiological indicators was analyzed by qualitative and quantitative determination of anthocyanins.The transcriptomes of the green,red and blue stages fruits were sequenced.The relationship between gene expression of anthocyanin-related genes,its enzymatic activity and anthocyanin accumulation was analyzed.Through the joint analysis,the process of anthocyanin synthesis in blueberry fruit was preliminarily discussed.The results are as follows:1.The fruits of green,pink,red,purple and blue stage(20,30,40,50 and 60 d after flowering)were used as study materials to determine the quality-related.The results showed that TAC continued to accumulate with the blueberry fruit maturing,the main species of anthocyanins are different in different periods of fruit.The main anthocyanins was cyanidin in the green fruit stage.The main anthocyanin was delphinidin in the red fruit stage,but found the main anthocyanin was malvidin in the blue fruit stage.After analyzing,delphinidin was the most important anthocyanin in blueberry,followed by mallow pigment.The results of antioxidants showed that TFC,TAC with TPC were significantly positively correlated at developmental stages of blueberry.POD and PPO oxidize phenolic compounds to hydrazine during tissue aging.POD can promote the oxidation of phenolic substances,the formation of ethylene and the increase of respiratory intensity.During the aging process,the content of phenolic substances was related to POD or PPO activity,but there was not significantly correlation during fruit growth.2.The enzyme activities of PAL,CHI,ANS and DFR in anthocyanin synthesis were determined.The results showed that with the maturity of blueberry fruit,CHI enzyme activity increased slowly from red fruit to blue fruit stage,the ANS enzyme activity decreased in the early stage,but it began to rise from red fruit stage to the blueberry matured.At this time,it was synergistic with the accumulation of anthocyanins,indicating that ANS and CHI are likely key enzymes for the synthesis of anthocyanins in blueberry fruits.3.Total RNA were extracted from the green,red and blue fruit of blueberry were transcriptome sequenced.In the constructed transcriptome database,68 uingenes involved in the anthocyanin biosynthesis pathway were found in the blueberry fruits.After combining with FPKM,log2 Ratio and other screening conditions,[PAL(CL3766.Contig1_All),CHS(CL177.Contig3_All),CHI(CL8506.Contig1_All),F3H(CL1218.Contig1_All),DFR(CL9744.Contig1_All),ANS(Unigene 14830_All)] were selected to use as candidate genes.4.We analyzed the expression levels of anthocyanin biosynthesisrelated genes through qRT-PCR.The results showed that structure genes in the pink fruit performed the highest expression level in the five periods,which was consistent with the anthocyanin accumulation.Genes ANS and CHS showed a high abundance expression levels during fruit coloration and might play important roles in anthocyanin biosynthesis.5.Based on transcriptome database,the full-length sequences of the coding regions of PAL,CHS,F3 H,DFR and ANS genes were successfully cloned by RT-PCR and sequence analysis methods.Bioinformatics analysis was found that these genes contain their own typical conserved domains.After combining with multiple sequence alignment and phylogenetic tree analysis,CHS,F3 H,DFR and ANS were species-specific,while PAL evolution was conservative.