Strawberry (Fragaria ananassa) is a widely grown horticultural crop, which exists in red, yellow, and white varieties. In recent years, the white-fleshed strawberry variety has gained more attention from consumers for its unique taste and appearance, but a comprehensive understanding of the molecular processes governing the ripening of white-fleshed strawberries remains undisclosed. In this study, based on the joint analysis of physiology, metabolome, and transcriptome, researchers screened and identified the key metabolites that were highly correlated to the maturation of white-fleshed strawberry (cv. 'snow-white', SW for short) fruits.
In contrast to red-fleshed strawberries, SW fruits exhibited three main ripening stages during the maturation, accompanied by increases in total soluble solid and total sugar and declines in total anthocyanin and total acid. Metabolomic analysis identified 832 differential accumulated metabolites (DAMs) at the secondary level of LC-MS/MS, and further investigations suggested that the increase in sucrose, citric acid, and epicatechin levels potentially plays a role in the ripening process of SW fruits. Furthermore, abscisic acid and methyl jasmonate were recognized as the primary phytohormones involved in the production of these metabolites. The enrichment analysis of RNA-Seq data revealed that the differentially expressed genes (DEGs) were primarily attributed to the pathways of 'Starch and sucrose metabolism' and 'Plant hormone signal transduction' but were undetected in 'Flavonoid biosynthesis' at the late ripening stage.
Moreover, the de novo biosynthesis pathway, WGCNA, and Pearson correlation analysis indicated a direct relationship between FaSPS1, FaSPP1, and FaSPP2 with sucrose, FaPEPC1, FaV-PPase2, and FaV-PPase3 with citric acid, and Fa4CL2, Fa4CL3, and FaANR1 with anthocyanin. Further analysis revealed a co-expression of MYBs, bHLHs, NACs, and WRKYs with the structural genes mentioned. Overall, the findings uncovered a molecular mechanism regulating the maturation of white-fleshed strawberries, providing valuable insights for enhancing the flavor of white-fleshed strawberries through the gene-editing technique.
Xu, L.; Chen, X.; Wang, Q.; Zhao, M.; Qiao, Y.; Xie, Z.; Sun, C.; Sun, M.; Cai, W. Metabolomic and Transcriptomic Analysis Revealed the Maturation Mechanism of White-Fleshed Strawberry. Agronomy 2024, 14, 2860. https://doi.org/10.3390/agronomy14122860
Source: MDPI