Camellia Species Research Articles

Comparative Genomic Analysis Uncovers the Chloroplast Genome Variation and Phylogenetic Relationships of Camellia Species.

Camellia is the largest genus in the family Theaceae. Due to phenotypic diversity, frequent hybridization, and polyploidization, an understanding of the phylogenetic relationships between Camellia species remains challenging. Comparative chloroplast (cp) genomics provides an informative resource for phylogenetic analyses of Camellia. In this study, 12 chloroplast genome sequences from nine Camellia species were determined using Illumina sequencing technology via de novo assembly. The cp genome sizes ranged from 156,545 to 157,021 bp and were organized into quadripartite regions with the typical angiosperm cp genomes. Each genome harbored 87 protein-coding, 37 transfer RNA, and 8 ribosomal RNA genes in the same order and orientation. Differences in long and short sequence repeats, SNPs, and InDels were detected across the 12 cp genomes. Combining with the complete cp sequences of seven other species in the genus Camellia, a total of nine intergenic sequence divergent hotspots and 14 protein-coding genes with high sequence polymorphism were identified. These hotspots, especially the InDel (~400 bp) located in atpH-atpI region, had sufficient potential to be used as barcode markers for further phylogenetic analysis and species identification. Principal component and phylogenetic analysis suggested that regional constraints, rather than functional constraints, strongly affected the sequence evolution of the cp genomes in this study. These cp genomes could facilitate the development of new molecular markers, accurate species identification, and investigations of the phylogenomic relationships of the genus Camellia.

Fatty acids and nutritional components of the seed oil from Wangmo red ball Camellia oleifera grown in the low-heat valley of Guizhou, China

Wangmo red ball Camellia oleifera is the main Camellia species cultivated for oil in the low-heat valley of Guizhou, China. In this study, we evaluated the comprehensive nutritional value of Wangmo C. oleifera seed oil through fatty acid and nutritional component analyses. Twenty excellent Wangmo C. oleifera plants with stable yield and disease resistance were selected from the Camellia oleifera germplasm resource garden in the low-heat valley site of Guizhou University. The unit crown yield, fatty acid content of the seed oil, fatty acid composition and functional nutrients were determined, and the oil quality was comprehensively evaluated using principal component analysis. The fatty acid content of C. oleifera seed oil was 35.03–53.47%, suggesting likely popularization and wide application prospects. The fatty acids included SFAs, MUFAs and PUFAs, and the oleic acid content was 80%, indicating a highly stable and nutritious oil. The oil was also rich in carotenoids, polyphenols, flavonoids, β-sitosterol, squalene and α-Ve, with average content of 7.404 mg/kg, 16.062 mg/kg, 0.401 g/100 g, 265.087 mg/kg, 129.315 mg/kg and 21.505 mg/100 g, respectively. However, the correlations among the nutritional indices were weak. PCA showed that germplasms GH7, GH43, GH28, GH8 and GH31 exhibited the top five nutritional qualities. The rankings in this study provide data for identifying excellent Wangmo C. oleifera plants with high nutritional quality. Additionally, this study provides a valuable reference for the research and development of high-end edible oil and a theoretical basis for the development of economic forest species in low-heat valley areas across the world.

DNA Barcode Identification of New Yellow Camellia Species: Endangered Plant Species in North Vietnam

DNA Barcode Identification of New Yellow Camellia Species: Endangered Plant Species in North Vietnam

Comprehensive lipidomics analysis reveals the changes in lipid profile of camellia oil affected by insect damage.

Information on changes in lipid composition of seed oils under biotic stresses is scare. The camellia weevil, Curculio chinensis (Coleoptera: Curculionidae) as a notorious seed predator of Camellia species, has caused huge economic losses in China. Lipidomics is used in this study to reveal the lipid composition of camellia oil and its changes after insect damage. 278 lipids including glycerolipids (GL) (221), glycerophospholipids (GP) (34), fatty acyls (FA) (13), sphingolipids (SP) (8), prenol lipids (PR) (1) and sterol lipids (ST) (1) were determined in camellia oils. Insect damage had a significant impact on lipids, particularly FA and GL. Ten significantly different lipids [FFA(18:2), FFA(24:6), TG(14:1/18:2/18:2), TG(16:0/23:0/18:2), TG(20:1/24:1/18:2), TG(18:2/24:0/18:2), TG(16:3/18:2/22:5), PI(16:1/18:1), PE(16:0/18:1), PE(18:1/18:2)] were identified as potential biomarkers for distinguishing oil extracted from non-infested oilseeds and oil from infested oilseeds. We also detected four most important metabolic pathways by bioinformatics analysis to explore the mechanisms underlying changes. Our findings may be useful for future camellia oil production and may provide new insight into improving of nutritional quality of camellia oil.

A new species of Coccomyces from oak leaves in Fodingshan National Nature Reserve in China

Specimens of Coccomyces on Quercus (Cyclobalanopsis, Fagaceae) collected from Fodingshan National Nature Reserve in Guizhou Province, China, were identified as a new species and named Coccomyces fodingshanensis. A multi-gene phylogenetic analysis (ITS, LSU, mtSSU) showed that the new species is closely related to Coccomyces sinensis on Camellia species but differed by subrounded ascomata and fagaceous host.

Anti-inflammatory/anti-oxidant properties and the UPLC-QTOF/MS-based metabolomics discrimination of three yellow camellia species

The species of Camellia nitidissima Chi (CC) and C. euphlebia Merr. ex Sealy (CE) are two most important plant sources for commercialized herbal tea (Jinhuacha) worldwide. However, some other species of camellia genus are also sold as alternatives in market due to the great commercial value. In this study, the similarity and difference of CC and CE as well as C.insularis (CI) are comprehensively compared both in chemistry and pharmacology. Based on the ultraperformance liquid chromatography coupled with a hybrid quadrupole orthogonal time-of-flight mass spectrometer(UPLC-QTOF-MS) analysis, a sequential-optimization based new statistical model has been developed by combining the untargeted metabolomics and fingerprint analyses, and successfully applied for chemical pattern recognition and discrimination of three yellow camellias species. The results indicated that CC, CE and CI could be well discriminated with the optimized chemical combination including quercetin-3-O-rhamnoside (C2), okicamelliaside (C4), Kaempferol 7-O-rhamnoside (C6), Corymboside (C9), asiatic acid-glc-rha-xyl (C11) and 3′-methy-4′-glucoside-ellagic acid (C14). Moreover, the 30 % ethanolic extracts of yellow camellias species presented the optimal activities on anti-inflammation/anti-oxidation in LPS-stimulated Raw264.7 macrophages dose-dependently. The averaged 50 % inhibitory concentrations (IC50) on NO production were 754.68 ± 50.96, 1182.39 ± 22.10, 1527.83 ± 106.24 μg(herb)/mL, and ROS production were 311.70 ± 26.57, 332.64 ± 25.46, 917.60 ± 41.36 μg(herb)/mL for CC, CE and CI, respectively. The results indicated a certain similarity of CC and CE, as well as their significant difference from CI.

Assessment of free and bound phenolics in the flowers and floral organs of two Camellia species flower and their antioxidant activities

Camellia flowers are an important oil source containing abundant phenolic compounds. The free and bound phenolic, flavonoid, and proanthocyanidin fractions and their antioxidant activity were investigated in Camellia oleifera flowers and Camellia polyodonta flowers, stamens, and petals. Phenolic compounds in C. oleifera were studied using high-resolution liquid chromatography-mass spectrometry, which revealed 85 phenolics, including flavonols > ellagitannins > procyanidins > phenolic acids > flavanone > organic acids. Free fractions contributed more greatly to phenolic content and antioxidant capacity than bound fractions in all samples. The highest total phenolics (138.96 mg GAE/g DW), total flavonoids (423.20 mg RE/g DW), and total proanthocyanidins (61.08 mg PB2E/g DW) were obtained in the C. polyodonta flowers, which also exhibited the highest total antioxidant activity. In terms of individual phenolic components, C. polyodonta possessed the highest content of procyanidin B2, procyanidin B4, procyanidin C1, and epicatechin, while C. oleifera displayed the highest content of flavonoids such as quercitrin and afzelin, particularly in the petals. These results implied that Camellia flowers are important natural sources of active components for use in the food industry.

Contrasting Adaptation Mechanisms of Golden Camellia Species to Different Soil Habitats Revealed by Nutrient Characteristics

Golden Camellia species are highly specific to certain soil environments. Most species are only native to calcareous soils in karst regions, except for a few that grow only in acidic soils. Our aim is to elucidate the adaptation mechanisms of the species of calcareous-soil golden Camellia (CSC) and acidic-soil golden Camellia (ASC) to habitat soils through plant–soil nutrient characteristics and their relationships. We investigated 30 indices for soils and plants. Compared with ASC, CSC had more fertile soil, while their plant tissues exhibited stronger Ca, P, and Mn and weaker K storage, which may be important mechanisms for adapting to habitat soils. However, ASC showed a higher biological absorption coefficient (BAC) for nutrients, which may contribute to the adaptation of ASC to relatively barren acidic soils. Both CSC and ASC showed much higher BAC and accumulation of Ca than other nutrients. We also found that the concentrations of nutrients in the different tissues varied considerably between species. Correlation analysis revealed 135 significant relationships between the 30 indices, with the soil pH and soil Ca levels being the most important factors influencing the nutrient uptake network. This information helps in understanding the adaptation mechanisms of karst plants to habitat soils.

Research on some agrochemical and soil characteristics of yellow camellia species in the Vu Quang National Park, Ha Tinh Province

Outward investment policy has been an important part of China's reform and opening-up since 1978. However, it has really made major breakthroughs since China stepped up the implementation of its “going out” strategy in the early years of the twenty-first century. Through preferential policies and measures on tax, financial and monetary reform, aid to countries, establishment of an investment support fund, and reform of administrative procedures, China is constantly expanding its investment to foreign countries, becoming one of the world’s leading countries in this field. China's investment development strategy has had a certain impact on Vietnam - China economic relations in the period 2010-2020. It has contributed to promoting Chinese investment in Vietnam, enhancing trade cooperation between the two countries; but on the other hand, it also makes the trade balance unbalanced, causing some limitations and inadequacies in the process of Chinese investment in Vietnam.

Impact of Cold Stress on Leaf Structure, Photosynthesis, and Metabolites in Camellia weiningensis and C. oleifera Seedlings

Camellia weiningensis Y. K. Li. sp. nov. (CW) is an endemic oil-tea species in Guizhou province, distributed in the alpine karst area, which exhibits cold resistance and better economic characters than C. oleifera (CO). The mechanism of cold response in CW seedlings has not been studied in depth. Herein, we performed anatomical, physiological, and metabolic analyses to assess the impact of cold stress on leaf structure, photosynthesis, and metabolites in CW and CO seedlings. Anatomical analysis of leaves showed CW seedlings had greater leaf and palisade thicknesses, tissue structure tightness, and palisade-spongy tissue ratio to enhance chilling stress (4 °C) tolerance, but freezing stress (−4 °C) caused loosening of the leaf tissue structure in both CW and CO seedlings. Photosynthetic analysis showed a reduction in the chlorophyll (Chl) fluorescence (Fv/Fm) and photosynthetic parameters under freezing stress in both CW and CO seedlings. Cold stress increased the abscisic acid (ABA) contents in both the Camellia species, and CW exhibited the highest ABA content under −4 °C treatment. Additionally, the indole-3-acetic acid (IAA) content was also increased in CW in response to cold stress. An obviously distinct metabolite composition was observed for CW and CO under different temperatures, and significantly changed metabolites (SCMs) were enriched under freezing stress. Prenol lipids, organooxygen compounds, and fatty acyls were the main metabolites in the two Camellia species in response to cold stress. The top key SCMs, such as medicoside G, cynarasaponin F, yuccoside C, and methionyl-proline were downregulated under freezing stress in both CW and CO. The contents of some key metabolites associated with sugar metabolism, such as UDP-glucose, UDP-D-apiose, and fructose 6-phosphate, were higher in CW than in CO, which may contribute to enhancing the cold resistance in CW. Our findings are helpful in explaining how CW adapt to alpine karst cold environments, and will provide a reference for cold tolerance improvement and application of stress-resistant breeding of Camellia in alpine and cold areas.

THREATS TO GOLDEN-FLOWERED CAMELLIAS ALONG HON GIAO PASS

The identification, documentation, and discussion of the main threats affecting the golden-flowered Camellia species endemic to Hon Giao Pass are discussed. Observations, published literature, and collations of data accumulated from field trips throughout Vietnam since 1999 are analyzed and researched for the preparation of the article. The major anthropogenic risk factors affecting the golden-flowered Camellia species and their habitats on the Dalat Plateau and along the Hon Giao Pass are named and reviewed. These risk factors include habitat loss due to population growth, logging, habitat fragmentation and degradation, poaching, collection of wild plant species, fire, and the construction of dams and their associated water impoundments.

YELLOW CAMELLIAS: A REVIEW OF CHEMICAL CONSTITUENTS AND BIOLOGICAL ACTIVITIES

To date, 69 species of yellow Camellia have been found in South China and Vietnam, and they have attracted substantial attention from scientists. Chemical and biological studies have only been carried out on a few species, with the main focus on the Chinese species Camellia nitidissima, but have shown that the main active ingredients of these yellow camellia species include flavonoids, phenolic compounds, saponins, triterpenoids, phytosterols, essential oils, amino acids, and polysaccharides. Many pharmacological studies have proved that the total extracts, fractions, and isolated substances from yellow camellia species possess antioxidant, anticancer, hypolipidemic, hypoglycemic, antiallergic, hepatoprotective, neuroprotective, anxiolytic, and antidepressant activities. This review systematically summarizes recent research results in order to provide a comprehensive and up-to-date understanding of the chemical composition and biological activities of yellow camellia species, creating a basis for research of the yellow camellia species in Vietnam and development of new products from this source.

CsMYB184 regulates caffeine biosynthesis in tea plants.

CsMYB184 regulates caffeine biosynthesis in tea plants.

Development of Novel Polymorphic Microsatellite Markers and Their Application for Closely Related Camellia (Theaceae) Species

Development of Novel Polymorphic Microsatellite Markers and Their Application for Closely Related Camellia (Theaceae) Species

THE DIVERSITY OF YELLOW CAMELLIAS IN THE CENTRAL HIGHLANDS, VIETNAM

The Central Highlands (Tây Nguyên) is a center of yellow camellia diversity in Vietnam and the world. The Central Highlands contains 18 of Vietnam’s yellow camellia species, accounting for 37% of yellow camellia species in Vietnam and 28% of yellow camellia species worldwide. Moreover, all 18 yellow camellia species in the Central Highlands are endemic to Vietnam. The camellias of the Central Highlands belong to nine sections, accounting for 75% of the world. The yellow colors occur in three groups: pale yellow, yellow, and yellow with compound colors. The yellow camellia distribution is dispersed at 500–1600 m elevation in evergreen broadleaf forests and mixed wood-bamboo forests.

A TAXONOMIC KEY FOR YELLOW CAMELLIAS IN THE CENTRAL HIGHLANDS OF VIETNAM

Eighteen yellow Camellia species are found in the Central Highlands of Vietnam. Their morphological characteristics are described and illustrated. Based on the morphological characteristics of the leaves, flowers, and fruit, a dichotomous key has been constructed.

Comparative Analysis of Purine Alkaloids and Main Quality Components of the Three Camellia Species in China.

Tea (Camellia sinensis var. sinensis) is a widely consumed caffeine-containing beverage, however the Camellia genus also includes other species, which are consumed as tea in their local growing regions. Presently, HPLC analysis assessed 126 unique Camellia germplasms belonging to three Camellia species, C. sinensis var. pubilimba Chang (Csp), C. gymnogyna Chang (CgC) and C. crassicolumna Chang (CcC). Theobromine was the predominant purine alkaloid in all species, representing over 90% of purine alkaloids in Csp and CgC, and 50% in CcC. Significant variability existed in purine alkaloid patterns both between and within species, and some germplasms possessed highly unique alkaloid profiles. Sensory evaluation and quality composition analysis of green tea products produced from the three Camellia species suggested their unsuitability for use in tea production due to their unpalatable flavor. The results of this study revealed the differences in purine alkaloids and main quality components between Camellia species and tea, which contributed to understand why tea, rather than other Camellia species, has become a popular beverage in the world after long-term artificial selection. In addition, unique alkaloid profiles suggest usefulness of these germplasm resources in future breeding of decaffeinated tea plant varieties and alkaloid metabolism research.

Comparison of the Chloroplast Genome Sequences of 13 Oil-Tea Camellia Samples and Identification of an Undetermined Oil-Tea Camellia Species From Hainan Province.

The comparison of chloroplast genome (cpDNA) sequences among different plant species is an important source of plant molecular phylogenetic data. In this paper, the cpDNA sequences of 13 different oil-tea camellia samples were compared to identify an undetermined oil-tea camellia species from Hainan Province. The cpDNA of the samples was sequenced and resequenced, and divergence hotspots and simple sequence repeat (SSR) variations were analyzed. Bayesian inference (BI) and maximum-likelihood (ML) phylogenetic trees were constructed based on the full cpDNA sequences. The cpDNA sequences were 156512∼157089 bp in length and had the circular tetrad structure typical of angiosperms. The inverted repeats (IRs) of different species included varying contractions and expansions. The cpDNA sequences of the samples of the undetermined species of oil-tea camellia from Hainan Province and Camellia gauchowensis from Xuwen County were identical. In total, 136 genes were annotated, including 91 protein-coding genes (PCGs), 37 tRNA genes and 8 rRNA genes. The GC content of the cpDNA was 37.3%. The small single-copy (SSC)/IR boundary was rich in variation. Divergence hotspots were mainly located in the intergenic space (IGS) and coding sequences (CDSs), and there were obvious differences in divergence hotspots among species. The same divergence hotspots were found in Camellia vietnamensis, Camellia gauchowensis and the undetermined species of oil-tea camellia from Hainan Province. A total of 191∼198 SSR loci were detected. Most of the SSRs included A or T, and the distribution of SSRs in the cpDNA was uneven. Different species shared common SSRs and exhibited unique SSRs. Based on the full cpDNA sequences, the evolutionary relationships of different species of Camellia were well identified. The thirteen samples were classified into 2 clades and 6 subclades, and the different sections of Camellia clustered on the same branch in 2 clades and 2 subclades. Camellia vietnamensis was more closely related to the undetermined species of oil-tea camellia from Hainan Province and the sample of Camellia gauchowensis from Xuwen County than to the sample of Camellia gauchowensis from Luchuan County. Camellia osmantha was closely related to Camellia gauchowensis and Camellia vietnamensis. In conclusion, the cpDNA of different oil-tea camellia species has a conserved tetrad structure with certain length polymorphisms. SSRs are expected to be developed as “barcodes” or “identity cards” for species identification. SSR variations and other factors result in abundant divergence hotspots in the CDSs and IGS (one non-CDS region), indicating that full cpDNA sequences can be used for the species identification and phylogenetic analysis of Camellia. Accordingly, the undetermined species of oil-tea camellia from Hainan Province is likely Camellia vietnamensis, Camellia vietnamensis and Camellia gauchowensis may be the same species, and additional genetic evidence is needed to determine whether Camellia osmantha is a new independent species. The previous division of related sections of Camellia may need readjustment based on full cpDNA sequences.

Complete chloroplast genome of a cultivated oil camellia species, Camellia gigantocarpa

Camellia gigantocarpa Hu et T. C. Huang, belonging to the Theaceae family, is an excellent landscape tree species with high ornamental value. It is also an important woody oil-bearing plant with high economic value. This study reports the first complete chloroplast genome sequence of C. gigantocarpa (GenBank accession number: MZ054232). Its whole chloroplast genome is 156,953 bp long with an overall GC content of 37.31%, which is composed of a large single copy region (86,631 bp), a small single copy region (18,402 bp), and a pair of inverted repeat regions (25,960 bp each). A total of 135 genes were predicted in this genome, namely eight ribosomal RNA genes, 37 transfer RNA genes, and 90 protein-coding genes. Based on maximum likelihood analysis results, we found that the Camellia species are clustered into a distinct branch, and the phylogenetic relationships among C. gigantocarpa, C. crapnelliana, and C. kissii were the closest.

Paclobutrazol Modulates Endogenous Level of Phytohormones in Inducing Early Flowering in Camellia tamdaoensis Hakoda et Ninh, a Golden Camellia Species

Golden camellia flowers are treasured for their unique yellow color and bioactive chemical compounds. Because of its high market demand, there is strong interest in inducing early flowering in golden camellias for earlier harvest. Previously, we have successfully induced flowering in Camelia chrysantha (Hu) Tuyama juvenile grafted plants and seedlings with paclobutrazol (PBZ). During this study, we investigated the efficacy of PBZ on C. tamdaoensis juvenile rooted cuttings. C. tamdaoensis is a yellow-flowering camellia species that is native to Vietnam and valued by the local population. It was found that applications of 100 and 200 ppm PBZ generated an average of 13 and 30 flowers per 5-year-old plant, respectively. None of the control plants flowered. The average flower diameter was 17.2 cm for 100-ppm-induced flowers and 26.0 cm for 200-ppm-induced flowers. The dynamics of various phytohormones (indoleacetic acid, abscisic acid, salicylic acid, and jasmonic acid) were altered by PBZ treatment. It is suggested that low indoleacetic acid, high abscisic acid, and jasmonic acid and a gradual increase in salicylic acid benefit floral initiation of golden camellias. The study provided the first insight regarding the action mechanism of PBZ for the initiation of camellia flowering.