Transcriptional Regulation Mechanism Of Terpenoids,Phenolic Acids And Flavonoids Metabolites In Ziziphus Jujuba Mill.cv.Goutou Jujube Fruit

Jujube is a medicinal and edible food.Flavonoids,terpenes and phenolic acids are the bioactive components in jujube fruit.Their synthesis and accumulation are closely related to the medicinal value,edible value and post-harvest storage of jujube fruit during fruit growth and development.These contents are also the important indicator for evaluating fruit quality and functionality.Their biosynthesis and accumulation are regulated by transcription factors and key gene.These bioactive components accumulation rule and main regulatory mechanism have not yet been elucidated in jujube fruit.The elucidation of the relevant metabolic regulation mechanism has important theoretical guidance and practical significance for improving the quality and functionality of jujube fruit.Here,the white-ripening Stage 1,half-red Stage 2,full red fruit Stage 3 and softening Stage 4 during the fruit ripening process of Goutou jujube were analyzed by extensive targeting of metabolomics and transcriptome.The analyze explored on the metabolites accumulation and rule regulation mechanism of flavonoids,terpenoids,and phenolic acid during the ripening period of jujube fruits.The results as following:(1)603 metabolites were detected in Goutou jujube fruit by metabolome,which belonged to 12 categories.Among them,there are 77 kinds of flavonoid metabolites,71 kinds of phenolic acid metabolites,and 53 kinds of terpenoid metabolites.Tannins and quinones are the least metabolized,with only three of each.(2)Stage 1-Stage 2 had the most differential metabolites,there are 217 differential metabolites,125 differential metabolites were up-regulated,and 92 differential metabolites were down-regulated.Stage 2-Stage 3 had 139 differential metabolites,78 were downregulated and 61 were up-regulated.Metabolite composition differences decreased gradually with deeper maturation and decreased metabolic activity.Stage 3-Stage 4metabolite composition was relatively stable with only 85 differential metabolites,of which 41 metabolites were up-regulated and 44 were down-regulated.(3)Most of the detected flavonoid metabolites were high in Stage 2 and Stage 3,terpenoid metabolites were high in the Stage 1 and Stage 2,and phenolic acid metabolites were all high in the periods have high expression.Among the flavonoid metabolites,quercetin 3-O-neohesperidin was the highest in Stage 1 and Stage 2,and the highest content in Stage 3 was quercetin-3-O-rutinoside.Cortex-3-O-(4’-O-glucosyl)rhamnoside was highest at Stage 4.The highest content of phenolic acid metabolites in Stage 1,Stage3,and Stage 4 was 4-nitrophenol,and the content of α-hydroxycinnamic acid in Stage 2was the highest.The terpenoid metabolite 2α,19α-dihydroxy-3-oxursop-12-ene-28-acid was the most abundant terpenoid in the four periods.(4)59 transcription factors were screened by transcriptome-metabolome association analysis,belonging to 24 transcription factor families.Twenty CYP450 family members belong to CYP71 family,CYP72 family and CYP86 family.Zj NAC-3,Zjb HLH-2,Zjb HLH-3,Zj NAC-2,Zj MYB-5 were screened out as key genes in the regulation of flavonoids,phenolic acids and terpenoids metabolism,Zj MYB-1,Zj MYB-4,Zj MYB-2,Zj MYB-8,Zj AP2,Zj ERF-1,Zj NAC-1,Zjb HLH-4 are specific transcription factors regulating flavonoid metabolites,Zj ERF-4 is a specific transcription factor regulating terpenoid metabolites,Zj ERF-3,Zj MYB-7,Zj MYB-6 is a related transcription factor that is uniquely regulated by phenolic compounds.(5)In the CYP450 family,Zj P450-1 and Zj P450-6 are the key genes in the synthesis of three types of metabolites,and the key genes in the synthesis of phenolic acid metabolites are Zj P450-8,Zj P450-10,Zj P450-20,Zj P450-11;regulation Flavonoid metabolite synthesis P450 s include Zj P450-2,Zj P450-3,Zj P450-4,Zj P450-5,Zj P450-12,Zj P450-13,Zj P450-14,Zj P450-15,Zj P450-17;terpenoid metabolite synthesis specific P450 s There are Zj P450-19,Zj P450-16.Through the analysis of the metabolome and transcriptome of Goutou jujube fruit at different maturity stages,the key genes in the regulation of flavonoids,phenolic acids and terpenoids synthesis were identified.These metabolites accumulation rule was preliminarily revealed in Goutou jujube.These findings are conducive to promoting the research of Goutou jujube and the development of Goutou jujube industry in northern Shaanxi.This research also provides a reference for the quality improvement and variety selection of Goutou jujube by molecular-assisted breeding strategies in the future.