Starch is one of the most important storage carbohydrates in plants. Kiwifruit typically accumulate large amounts of starch during development. The fruit retain starch until commercial maturity, and its postharvest degradation is essential for consumer acceptance. The activity of genes related to starch degradation has, however, rarely been investigated. Based on the kiwifruit genome sequence and previously reported starch degradation-related genes, 17 novel genes were isolated and the relationship between their expression and starch degradation was examined using two sets of materials: ethylene-treated (100 µL/L, 20 °C; ETH) vs. control (20 °C; CK) and controlled atmosphere stored (CA, 5% CO₂ + 2% O₂, 0 °C) vs. normal atmosphere in cold storage (NA, 0 °C). Physiological analysis indicated that ETH accelerated starch degradation and increased soluble solids content (SSC) and soluble sugars (glucose, fructose and sucrose), while CA inhibited starch reduction compared with NA. Using these materials, expression patterns of 24 genes that may contribute to starch degradation (seven previously reported and 17 newly isolated) were analyzed. Among the 24 genes, AdAMY1, AdAGL3 and AdBAM3.1/3L/9 were significantly induced by ETH and positively correlated with starch degradation. Furthermore, these five genes were also inhibited by CA, conforming the likely involvement of these genes in starch degradation. Thus, the present study has identified the genes with potential for involvement in starch degradation in postharvest kiwifruit, which will be useful for understanding the regulation of kiwifruit starch content and metabolism.

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.

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 most different pigments and the underlying regulatory mechanisms of differential expression genes (DEGs) between red and yellow fruits of sweet cherry. Profiled the two cultivars,‘Jiangnanhong’(JNH, red fruits) and‘Chaoyang’(CY, yellow fruits) anthocyanin and carotenoid metabolites by LC-MS/MS and transcriptome analysis by RNA-seq to test the difference of 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 yellow one during the whole ripening stage (stage 3 and stage 4). Total carotenoid content in the two color types of fruits were close, but the content in yellow fruit showed 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) 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 that in CY, contrastly, there were some strong correlations were observed between 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.

This study aimed to characterize carotenoid profiles and unravel the genetic mechanisms underlying flesh color variation in white and yellow-fleshed peaches, with a focus on the hybrid cultivar ‘ZY29’ derived from two white-fleshed parents (‘Yulu’ and ‘Hujing Honey Dew’). Using UPLC-APCI-MS/MS, we quantified carotenoids in the pericarp (exocarp) and flesh (mesocarp) of parental and hybrid fruits. Results showed that ‘ZY29’ accumulated significantly higher levels of β-carotene and lutein compared to its white-fleshed parents. Transcriptome analysis revealed upregulation of carotenoid biosynthesis genes (PSY, LCYB, and ZDS) and downregulation of the carotenoid cleavage gene CCD4 in ‘ZY29’, explaining enhanced carotenoid accumulation. Integrative metabolome-transcriptome analysis identified core regulatory networks associated with metabolic shifts, including transcription factors (MYB and WRKY). These findings provide novel insights into the molecular basis of yellow flesh formation in peaches, offering potential targets (PSY and LCYB) and metabolic markers (β-carotene and lutein) for breeding nutritionally enriched cultivars. These findings contribute to a better understanding of the genetic factors and parental regulatory mechanisms involved in the formation of yellow flesh color in peaches. Our results have important implications for breeding new peach varieties with desirable color and nutritional qualities and may provide valuable insights for future research in this area.