Comparative metabolomic analysis reveals nutritional properties and pigmentation mechanism of tea-scented rosehips.

BACKGROUND: The fruits of the genus Rosa, commonly known as rosehips, have attracted significant attention owing to their rich content of various bioactive compounds. However, their utility is generally secondary to the ornamental appeal of their flowers. This study aimed to explore the quality differences among tea-scented rosehips found in Yunnan, China, including those of Rosa odorata var. odorata (RO), Rosa odorata var. gigantea (RG), and Rosa yangii (RY). Morphological characteristics, chemical composition, and antioxidant activity of their fruits were evaluated. RESULTS: The study revealed significant variability in composition and biological activities based on fruit color. RO exhibited the highest levels of polyphenols, flavonoids, anthocyanins, carotenoids, and vitamin C, with the strongest antioxidant activity (10.99 µmol Trolox·g-1 ), followed by RG (7.91 µmol Trolox·g-1 ) and RY (6.52 µmol Trolox·g-1 ). This supports RO's potential as a functional food source. Untargeted metabolomics identified and quantified 502 metabolites, with flavonoids (171) and phenolic acids (147) as the main metabolites. The differential metabolites among the fruits are primarily enriched for flavonoid biosynthesis and phenylpropanoid biosynthesis pathways. Insights into color formation supported the role of anthocyanins, flavones, and flavonols in fruit color variation. CONCLUSION: Tea-scented rosehips offer vibrant colors and high nutritional value with potent biological activities. Rosa odorata var. odorata stands out as a functional food source owing to its rich bioactive compounds. These findings lay the groundwork for utilizing rosehips in functional foods, health supplements, and food additives, emphasizing the practical and beneficial applications of Rosa spp. independent of their ornamental value. © 2023 Society of Chemical Industry.

Widely Targeted Metabolic Profiling Reveals Differences in Polyphenolic Metabolites during Rosa xanthina f. spontanea Fruit Development and Ripening.

Rose hips are rich in various nutrients and have long been used for food and medicinal purposes. Owing to the high phenolic content, rose hips can be used as natural antioxidants. In this study, ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to conduct a widely targeted metabolomics analysis on the polyphenolic components of Rosa xanthina f. spontanea in three ripening stages: unripe, half-ripe and fully ripe fruit. A total of 531 polyphenol metabolites were detected, including 220 phenolic acids, 219 flavonoids, 50 tannins and 42 lignans and coumarins. There were 160 differential metabolites between unripe and half-ripe rose hips (61 downregulated and 99 upregulated) and 157 differential metabolites between half-ripe and fully ripe rose hips (107 downregulated and 50 upregulated). The results of our study not only greatly enrich the chemical composition database of rose hips but also provide metabolomics information on the changes in polyphenolic metabolism during fruit development for the first time, which will help select the optimal harvest time of rose hips to achieve better quality.

Dissecting the Genome-Wide Evolution and Function of R2R3-MYB Transcription Factor Family in Rosa chinensis.

Rosa chinensis, an important ancestor species of Rosa hybrida, the most popular ornamental plant species worldwide, produces flowers with diverse colors and fragrances. The R2R3-MYB transcription factor family controls a wide variety of plant-specific metabolic processes, especially phenylpropanoid metabolism. Despite their importance for the ornamental value of flowers, the evolution of R2R3-MYB genes in plants has not been comprehensively characterized. In this study, 121 predicted R2R3-MYB gene sequences were identified in the rose genome. Additionally, a phylogenomic synteny network (synnet) was applied for the R2R3-MYB gene families in 35 complete plant genomes. We also analyzed the R2R3-MYB genes regarding their genomic locations, Ka/Ks ratio, encoded conserved motifs, and spatiotemporal expression. Our results indicated that R2R3-MYBs have multiple synteny clusters. The RcMYB114a gene was included in the Rosaceae-specific Cluster 54, with independent evolutionary patterns. On the basis of these results and an analysis of RcMYB114a-overexpressing tobacco leaf samples, we predicted that RcMYB114a functions in the phenylpropanoid pathway. We clarified the relationship between R2R3-MYB gene evolution and function from a new perspective. Our study data may be relevant for elucidating the regulation of floral metabolism in roses at the transcript level.

Distribution of 45S rDNA in Modern Rose Cultivars (Rosa hybrida), Rosa rugosa, and Their Interspecific Hybrids Revealed by Fluorescence in situ Hybridization.

To elucidate the evolutionary dynamics of the location and number of rDNA loci in the process of polyploidization in the genus Rosa, we examined 45S rDNA sites in the chromosomes of 6 modern rose cultivars (R. hybrida), 5 R. rugosa cultivars, and 20 hybrid progenies by fluorescence in situ hybridization. Variation in the number of rDNA sites in parents and their interspecific hybrids was detected. As expected, 4 rDNA sites were observed in the genomes of 4 modern rose cultivars, while 3 hybridization sites were observed in the 2 others. Two expected rDNA sites were found in 2 R. rugosa cultivars, while in the other 3 R. rugosa cultivars 4 sites were present. Among the 20 R. hybrida × R. rugosa offspring, 13 carried the expected number of rDNA sites, and 1 had 6 hybridization sites, which exceeded the expected number by far. The other 6 offspring had either 2 or 3 hybridization sites, which was less than expected. Differences in the number of rDNA loci were observed in interspecific offspring, indicating that rDNA loci exhibit instability after distant hybridization events. Abnormal chromosome pairing may be the main factor explaining the variation in rDNA sites during polyploidization.