Microbial biofertilizers increase fruit aroma content of Fragaria × ananassa by improving photosynthetic efficiency

Fragaria × ananassa is a widely-consumed fruit worldwide, valued for its pleasant flavor and nutritional properties. However, its lack of fragrance, unlike wild strawberries, results in customer dissatisfaction. In this study, we tested whether the biofertilizer Saccharomyces cerevisiae can enhance the aroma of strawberry. We used different fertilization methods, namely, mycorrhizal fertilization (MF) and foliar fertilization (FF), to investigate the effects of S. cerevisiae on various characteristics of F. ananassa. The results showed that the application of yeast under MF significantly increased the amount of soluble sugars and total volatiles. However, no significant difference was detected in the anthocyanin content. The amount of total volatiles in fruits under different treatments was 18.17 (MF), 11.78 (FF), and 9.51 (control) μg·g−1 fresh weight (FW). The main volatiles obtained from the fruits under MF, FF, and control treatments were esters (51.45%, 44.39%, and 29.39%, respectively), alcohols (35.93%, 28.77%, and 6.58%, respectively), and aldehydes (5.86%, 18.31%, and 62.88%, respectively). The photosynthetic rate and intercellular CO2 concentration were significantly influenced by the utilization of yeast strains. The MF treatment with yeast resulted in higher photosynthetic rate, and the plants from the FF treatment recording the highest intercellular CO2 concentration. Integrating the data of metabolites, it was suggested that S. cerevisiae, by generating CO2, promotes photosynthesis, leading to the increased sugar content in the fruits, which subsequently enhances the content of 3(2H)-Furanone, 4-methoxy-2, 5-dimethyl (DMMF) and phenylalanine-derived volatiles.