Changes Of Flavor Substances And Expressions Of Related Genes In The Development Process Of Chinese Olive Fruit

The paper was aimed to investigate the effect of phenolic compounds on the flavor of Chinese olive[Canarium album(Lour.)Raeusch]using'Chang ying'?'Qing lanl' as materials to determine substances including total soluble solids(TSS),soluble sugar,titratable acid(TA),tannin,flavone and polyphenol.In the meanwhile,to investigate the flavor formation mechanism combining with the transcriptome sequencing in order to obtain the metabolic pathways about the main substances,to clone the differentially expressed genes and determine their expressions during the whole growth and development periods.The paper provided a theoretical and practical basis for the selection of Chinese olive varieties and the improvement of fruit quality.The results were as follows:1.The changes of fruit favor in 'Chang ying'and 'Qing lanl' during growing development:'Chang ying' and 'Qing lanl' which had same shape,showed the same change on content of sugar' and acid,while phenolic compounds had big differences.The volume and flavor substances were accumulated among 50-110 d after flowering,and the phenolic appeared a small reduction among 70-90 d after flowering in'Qing lanl'.The content of soluble solids and sugar had accumulation while the others were decreased among 110-170 d after flowering.'Chang ying' had better to harvest at 110 d after flowering for good flavor,'Qing lanl' at 170 d.The results showed that the flavor formation of Chinese olive had a little relationship with sugar and acid,which was closely related to phenolic compounds.After flowering about 110 d was the key period to study the formation of Chinese olive flavor.2.Based on the phenylalanine metabolic,four metabolism pathways of phenolic substances in the transcriptome sequencing was integrated,and 20 differentially expressed genes were found as follows:HCT?CHI?FLS?C3H?C4H?PAL?POD?4CL?F5H?C3M?CPS??-DX??-glc?F3H?TAT?HPPD?AOS?CAD and hbd gene.The paper obtained the open reading frame(ORF)of 20 differentially expressed genes using RT-PCR cloning technology,and made a series of predictive analyses on the proteins encoded by related genes.Results showed that:The sequence lengths of related genes were between 663-3582 bp.The proteins encoded by CAD?hbd gene were hydrophobic proteins,the others were hydrophilic proteins.The proteins encoded by HCT?CHI?FLS?PAL?4CL?F5H?C3M?CPS??-glc?F3H?TAT?HPPD?CAD gene were acidity,the others were alkalinity.The proteins encoded by CPSs?CPSl?AOS gene were located in the chloroplast site.The proteins encoded by CHI?F3H?HPPD gene had no transmembrane protein,the others contained more than one transmembrane structures with cross-membrane function.The proteins encoded by related genes were composed of the alpha helix?the angle of rotation and so on,and had near relationships with Citrus sinensis?Mangifera indica and Durio zibethinus.3.The paper determined expressions of 20 related genes by qRT-PCR technology in 'Chang ying' and 'Qing lanl' fruit during the whole growth and development periods,and analyzed their correlation with the trend of phenolics substance content.Results showed that:The difference of phenolic substance content in two varieties was the result of the interaction of multiple genes in phenylalanine metabolism pathway.The gene expressions in condensed tannins,flavonoids synthesis metabolism branch were higher in 'Chang ying' during the whole periods,especially the phenolics synthesis stage(50-110 d after flowering),meanwhile in lignin and citric acid metabolism branch were higher in 'Qing lanl'.The correlation analysis concluded that the synthesis metabolic pathways of flavonoids and condensation tannins might be the key branches of the metabolism of Chinese olive phenols,HPPD?POD?CPSs?FLS?F3H?4CL?CHI?PALgene might be the key genes for the flavor of Chinese olive.