类球红细菌代谢产物对杨梅生长和果实品质的影响OA

To investigate the effects of Rhodobacter sphaeroides metabolites on fruit quality of Chinese bayberry,Myrica rubra Dongkui was used as the experimental material.The concentrated metabolites diluted 50-,100-,and 200-fold were applied via root irrigation during the fruit expansion stage,with water treatment as the control.The effects of each treatment on spring shoot growth and fruit quality of Chinese bayberry were compared and analyzed,and the active components in the metabolites were detected using non-targeted metabolomics and hormone quantitative analysis.The results showed that compared with the control,none of the treatments significantly affected spring shoot length,spring shoot diameter,or leaf SPAD value,but they significantly(p<0.05)increased leaf thickness and single fruit weight.Among them,the 50-fold and 200-fold dilution treatments increased single fruit weight by 35.64％and 38.70％,respectively.Regarding fruit quality,all treatments significantly increased soluble solids content,with the 100-fold dilution treatment showing the greatest increase(2.11 percentage points).The 200-fold dilution treatment significantly increased total sugar content,while the 50-fold dilution treatment significantly reduced titratable acid content,thereby significantly increasing the sugar-acid ratio.In addition,the 100-fold dilution treatment significantly increased total flavonoid content in fruit by 45.83％.Metabolite analysis revealed that the metabolites of Rhodobacter sphaeroides contained γ-aminobutyric acid(0.90 µg·mL-1)and relatively high concentrations of auxins(e.g.,indolepropionic acid at 79.33 ng·mL-1).In conclusion,the metabolites of Rhodobacter sphaeroides can synergistically improve the flavor and nutritional quality of Chinese bayberry by regulating the sugar-acid metabolic network and promoting the accumulation of functional components.This effect may be related to the synergistic regulation of γ-aminobutyric acid and auxins present in the metabolites.This study provides a theoretical basis and practical reference for the application of microbial metabolites in high-quality cultivation of Chinese bayberry.