Search Results (5)

Camellia drupifera, a valuable woody oil crop, holds significant ecological, economic, and medicinal importance. Its seed maturation involves intricate physiological changes, particularly the interplay between oil biosynthesis and sugar metabolism. This study investigates sugar accumulation and the expression dynamics of sugar metabolism-related unigenes during three key developmental stages of C. drupifera fruit: the nutrient synthesis stage (NS), fat accumulation stage (FA), and maturation stage (MS). The findings reveal distinct differences in sugar content and regulatory mechanisms across the stages. The NS stage emerges as a critical period for sugar metabolism, characterized by peak levels of soluble sugars and fructose alongside a significantly elevated expression of sugar metabolism-related unigenes. The significant correlation between sucrose content and gene expression suggests a crucial role of carbohydrates in fruit maturation. Transcriptomic analysis identified key differentially expressed unigenes (DEGs) in sugar metabolism pathways, which qRT-PCR further validated. These results offer novel insights into the molecular mechanisms regulating sugar metabolism during C. drupifera fruit development. At the same time, it provides a theoretical basis for the genetic improvement and effective utilization of other oil crops, supporting their broader agricultural and industrial applications. Full article

Oil–tea camellia has a long history of cultivation and utilization, with a history of more than 2000 years. In China, it is the main woody oil crop with high economic value and a national resource with unique characteristics. Concurrently, it is also known as one of the four major woody oil crops in the world. However, the genetic background of Camellia drupifera Lour. on Hainan Island in China is still unclear, and there is a great lack of systematic genetic characterization, which seriously hinders the development and utilization of oil–tea camellia germplasm resources and genetic improvement on Hainan Island. To analyze the genetic diversity and kinship between C. drupifera and its related species, this study utilized SSR molecular marker technology to genotype 160 individuals from 23 populations. A total of 137 alleles were amplified from the 14 polymorphic primers, with an average of 9.786. The average number of effective alleles and that of Shannon’s information index for each locus were 1.865 and 0.633, respectively, suggesting that the screened SSR markers presented a moderately high level of polymorphism. Additionally, the mean observed heterozygosity (0.915) was greater than the mean expected heterozygosity (0.450), indicating an excess of heterozygotes in the tested population. The results of the principal component analysis (PCA), molecular variation analysis of variance (AMOVA) and population structure analysis were generally consistent; specifically, there was a high degree of individual heterozygosity within the population, and genetic variation occurred primarily among individuals within the population (90%) but rarely among groups (10%). Additionally, the UPGMA clustering divided the 160 germplasm resources into four major clades, and C. drupifera was principally grouped in two distinct branches; meanwhile, Camellia gauchowensis was also mainly clustered in these two clades. Camellia oleifera individuals were chiefly concentrated in other independent branches. It can be speculated that C. drupifera is genetically close to C. gauchowensis, but genetically distant from C. oleifera. This study can provide the scientific basis for the identification, collection, preservation, evaluation, and innovative utilization of oil–tea camellia. Full article

Camellia drupifera is mainly used in forestry for its high-value industrial products; however, limited information is available on its transcriptome. This study aimed to construct a full-length transcriptome sequence based on the PacBio sequencing platform for various plant parts of C. drupifera, including flower buds, leaves, leaf buds, branches, the pericarp, and seed kernels. The transcriptomes were annotated with 23,207 genes, with 58 subgroups in the GO classification. The KEGG database revealed 10,407 genes involved in the metabolic pathway analysis, with 68,192 coding sequences, 3352 TF families, 48,541 SSRs, 1421 IncRNAs, and 2625 variable shears predicted. The transcriptomes of different parts were analyzed and compared. The majority of differentially expressed genes (DEGs) were found between the pericarp and seed kernels, followed by leaves and the pericarp with 5662 DEGs, and flower buds and leaf buds with 1616 DEGs. GO and KEGG enrichment analyses showed that KEGG differential genes were significant in microbial metabolism, carbon metabolism, and other functions. The data annotation and analysis of the full-length transcriptome and the comparative analysis between different plant parts provided a theoretical basis for studying gene function, metabolic pathway regulation, and gene expression analysis in KEGG. Full article

Camellia drupifera is an important woody oil plant in South China, renowned for its seed oil that is rich in unsaturated fatty acids and possesses significant antioxidant, anti-cancer, and immune-enhancing properties. The low fruit-setting rate of C. drupifera is influenced by multiple factors, including flowering stage climate, flowering habits, pollination biology, soil conditions, and self-incompatibility. Among these, large-scale pure forest plantations are the primary cause of the low fruit-setting rate. Although previous studies have explored the impact of self-incompatibility on fruit-setting in C. drupifera, research on the dynamic changes of endogenous substances during the flowering stage in pure forest environments remains limited. Research findings indicate that tannase activity is relatively high in the pistils of C. drupifera, creating a favorable environment for pollen tube growth. Plant hormones such as indole-3-acetic acid (IAA), cytokinin (CTK), gibberellin (GA), and ethylene (ETH) regulate the development and aging of floral organs through complex interactions. Specifically, high levels of IAA in the pistil promote pollen tube growth, while changes in ETH and ABA are closely related to the aging of floral organs. Under oxidative stress conditions, high levels of H₂O₂ in the pistil may contribute to self-incompatibility. The activity of superoxide dismutase (SOD) in the floral organs during the flowering stage is significantly higher compared to peroxidase (POD) and catalase (CAT), highlighting the critical role of SOD in regulating oxidative stress during this stage. This study provides new insights into the changes in endogenous substances in the floral organs of C. drupifera during the flowering stage. It offers theoretical references for understanding its sexual reproduction process and for the application of plant growth regulators to improve fruit setting. Full article

Aluminum (Al) affects the yield of forest trees in acidic soils. The oil tea plant (Camellia drupifera Lour.) has high Al tolerance, with abundant phenolic compounds in its leaves, especially flavonoid compounds. The role of these flavonoids in the Al resistance of oil tea plants is unclear. In this metabolomic study of C. drupifera under Al stress, ultra-pressure liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) was utilized to identify metabolites, while principal component analysis, cluster analysis, and orthogonal partial least squares discriminant analysis were applied to analyze the data on the flavonoid metabolites. The leaf morphology of C. drupifera revealed significant damage by excess aluminum ions under each treatment compared with the control group. Under Al stress at 2 mmol/L (GZ2) and 4 mmol/L (GZ4), the total flavonoid content in C. drupifera leaves reached 24.37 and 35.64 mg/g, respectively, which are significantly higher than the levels measured in the control group (CK) (p < 0.01). In addition, we identified 25 upregulated and 5 downregulated metabolites in the GZ2 vs. CK comparison and 31 upregulated and 7 downregulated flavonoid metabolites in GZ4 vs. CK. The results demonstrate that different levels of Al stress had a significant influence on the metabolite profile of C. drupifera. It was found that the abundance of the 24 differential flavonoid metabolites was gradually elevated with increasing concentrations of Al stress, including catechin, epicatechin, naringenin-7-glucoside, astilbin, taxifolin, miquelianin, quercitrin, and quercimeritrin. Moreover, the most significant increase in antioxidant activity (about 30%) was observed in C. drupifera precultured in leaf extracts containing 7.5 and 15 μg/mL of active flavonoids. The qRT-PCR results showed that the expression levels of key genes involved in the synthesis of flavonoids were consistent with the accumulation trends of flavonoids under different concentrations of Al. Therefore, our results demonstrate the key role of flavonoid compounds in the oil tea plant C. drupifera in response to Al stress, which suggests that flavonoid metabolites in C. drupifera, as well as other aluminum-tolerant plants, may help with detoxifying aluminum. Full article