树莓果实糖酸积累规律OA

Taking flori-cane raspberry'Caroline'and primo-cane raspberry'Autumn Bliss'as test materials,sugar and acid components,key enzyme activities,and gene expression levels at different developmental stages of the fruits,as well as the sugar and acid composition of mature fruits from 36 varieties were measured,in order to analyze the accumulation patterns and regulatory mechanisms of sugars and acids in raspberry fruits,thereby providing a reference for future molecular breeding strategies aimed at cultivating high-quality raspberry varieties.The results showed that,in'Caroline',glucose,sucrose,sorbitol,and total sugar contents increased initially and then decreased,while fructose exhibited continuous accumulation;in'Autumn Bliss',glucose,fructose,and total sugar demonstrated sustained increases,whereas sorbitol and sucrose displayed an initial rise followed by decline.Both cultivars exhibited similar trends for malic acid content,citric acid content,and total acid content,characterized by an initial increase and decrease subsequently.Activity of SPS and expression of RiSPS gene peaked at the color-turning stage and reached minimal levels at the red fruit stage in both cultivars.Activity of PFK and expression of RiPFK gene showed a continuous increasing in'Caroline'.In'Autumn Bliss',activity of PFK exhibited an increase-decrease-increase pattern,while the expression of RiPFK increased continuously.Activity of CS progressively increased in'Caroline',while in'Autumn Bliss',it decreased from the green fruit to white fruit stage then rising.Activity of NAD-MDH increased steadily in both cultivars,corresponding with the expression profiles of RiMDH and RiCS,aligning with enzyme activity dynamics.Among the 36 varieties,reducing sugars accounted for 77.5％of total sugar,while citric acid accounted for 95.9％of total acid,indicating that reducing sugars and citric acid are the predominant accumulating components in raspberry fruits.