The diversity of fruit color in sweet cherry (Prunus avium L.) has been attributed to the presence of either anthocyanin or carotenoid. We profiled the anthocyanin and carotenoid metabolites to investigate the different pigments and the underlying regulatory mechanisms of differential expression genes (DEGs) between red and yellow fruits of sweet cherry. We profiled two cultivars, ‘Jiangnanhong’(JNH, red fruits) and ‘Chaoyang’(CY, yellow fruits) to establish their anthocyanin and carotenoid metabolites by LC-MS/MS and transcriptome analysis by RNA-seq to test the difference in gene expression and metabolic substances between the two varieties. Cyanidin-3-O-rutinoside was the most different pigment between two cultivars, the content of which in red fruit was significantly higher than in the yellow one during the whole ripening stage (stage 3 and stage 4). The total carotenoid content in the two color types of fruits was close, but the content in yellow fruit was shown to be more stable after harvest. Based on the transcriptome data, the heatmap of selected structural DEGs showed that all of the anthocyanin genes expressed significantly higher levels in red fruits than that in yellow fruits. Two unigenes encoding chalcone synthase (CHS) and UDP glucose-flavonoid 3-O-glucosyltransferase (UFGT) were expressed 1134.58 and 1151.24 times higher in red than in yellow fruits at stage 4, respectively. Correlation analysis showed that anthocyanin genes in JNH were negatively correlated with those in CY; by contrast, there were some strong correlations observed between the two cultivars in carotenoid genes. Thus, the coloration of sweet cherry was mainly attributed to anthocyanin-related genes.

Sweet cherry (Prunus avium L.), renowned for its vibrant color and distinctive flavor, enjoys widespread popularity and is planted in temperate climates. This study investigated four short-chilling requirement cultivars in southeast China, which is known as a subtropical climate region, and determined several key fruit qualities, such as color, size, weight, and nutrient attributes (e.g., vitamin C, soluble sugar, organic acid, protein, gibberellin, and brassinolide) at four maturities due to the climate’s effect on the fruit color and the main color substance: anthocyanin accumulation. Therefore, the color index (a*, b*, and L*) and anthocyanin content were determined, and the anthocyanin-related gene expression was quantitative and analyzed using WGCNA. The results showed that the red variety, ‘Jiangnanhong’, exhibited the highest fruit weight and diameter as well as the greatest concentration of cyanidin-3-rutinoside (C3R). Conversely, the yellow variety, ‘Chaoyang 1’, demonstrated higher L* and b* values along with a greater vitamin C content. The research confirmed that C3R is the predominant anthocyanin present in sweet cherries during ripening. Additionally, three genes—LOC110744862, LOC110749842, and LOC110753376—were identified as playing crucial roles in anthocyanin biosynthesis. Anthocyanins significantly influence both the visual appeal and nutritional quality of the fruit. These results provide a theoretical foundation for understanding the differences among sweet cherry varieties in southeast China.

Gibberellin (GA) is an important plant hormone that is involved in various physiological processes during plant development. Sweet cherries planted in southern China have always encountered difficulty in bearing fruit. In recent years, gibberellin has successfully solved this problem, but there has also been an increase in malformed fruits. This study mainly explores the mechanism of malformed fruit formation in sweet cherries. By analyzing the synthesis pathway of gibberellin using metabolomics and transcriptomics, the relationship between gibberellin and the formation mechanism of deformed fruit was preliminarily determined. The results showed that the content of GA₃ in malformed fruits was significantly higher than in normal fruits. The differentially expressed genes in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were mainly enriched in pathways such as “plant hormone signal transduction”, “diterpenoid biosynthesis”, and “carotenoid biosynthesis”. Using Quantitative Real-Time Reverse Transcription PCR (qRT-PCR) analysis, the gibberellin hydrolase gene GA2ox and gibberellin synthase genes GA20ox and GA3ox were found to be significantly up-regulated. Therefore, we speculate that the formation of malformed fruits in sweet cherries may be related to the accumulation of GA₃. This lays the foundation for further research on the mechanism of malformed sweet cherry fruits.

Sweet cherry (Prunus avium L.) is popular with the public because of its bright color and unique taste. In order to determine the changes of fruit quality of sweet cherry in southern China, the fruit quality of sweet cherry in southern China was analyzed. The results showed that the red variety 'JNH' had the largest single fruit weight and diameter, and the highest content of C3R. The yellow variety 'CY' has higher L* value, b* value and Vitamin C content. It was determined in this experiment that the main anthocyanin content in sweet cherry fruits during the ripening period was C3R. LOC110744862, LOC110749842 and LOC110753376, which participate in anthocyanin biosynthesis, were finally screened. Anthocyanin plays an important role in the fruit appearance and nutritional quality. The results provided a theoretical basis for the differences among sweet cherry varieties in southern China.