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Camellia japonica, an evergreen ornamental plant in the Theaceae family, has a natural range that is now shrinking. This is evident by the fact that the species is on the verge of extinction in Laoshan Mountain (Qingdao), the northernmost area of China known to have a natural population of C. japonica. Little is known about the genetic diversity and relationships among cultivated and wild C. japonica populations. One hundred and eighty samples of six C. japonica populations were tested for genetic diversity with simple sequence repeat (SSR) markers; these included three cultivated populations, two natural populations in Qingdao, and one natural population in Daqingshan. The average values of polymorphism information content (PIC), expected heterozygosity (He), and Shannon’s information index (I) were 0.5849, 0.6385 and 1.3170, respectively, indicating that C. japonica has a high genetic diversity. The genetic diversities of the six populations in rank order were as follows: Daqingshan > Zhongshan Park > Changmenyan Island > Daguan Island > Botanical Garden > May Fourth Square. The geographical isolation of the islands had no significant influence on the genetic diversity of C. japonica. Clustering results showed that the six C. japonica populations could be grouped into three categories, and most populations were clustered according to their geographical origin and genetic background. These results also reconfirmed that the C. japonica (Naidong) population in Qingdao originated from Changmenyan Island. Genetic variation was highest within populations (89%), indicating that C. japonica can be protected at the population level. These findings will prove useful for the genetic analysis, protection, and horticultural use of C. japonica.

Camellia japonica is a woody flower with high ornamental and economic value used for landscaping and as a pot plant. Floral colors are among the most important ornamental traits of flower plants, particularly multicolored flowers. The C. japonica cultivar ‘Joy Kendrick’ has multicolored flowers; the corolla is pink with darker red stripes, but the molecular mechanism underlying this trait is unknown. Here, pigment analysis showed that there are more anthocyanins accumulate in red petal regions than in pink areas, which may be key to formation of red stripes. Furthermore, transcriptome analysis revealed that anthocyanin biosynthesis, modification, and transporter genes are highly expressed in red stripes, consistent with the observed anthocyanin accumulation. In addition, many plant hormone signal transduction genes, particularly auxin, may contribute to the regulation of red stripe formation. This study provides broad insights into pigment accumulation and the regulatory mechanisms underlying floral color formation in C. japonica, and lays a foundation for breeding new C. japonica varieties.

A new positive-strand RNA virus genome was discovered in Camellia japonica plants. The complete genome of the virus is 12,570 nt in size, excluding the poly(A) tail, and contains one large open reading frame (ORF1) and two small open reading frames (ORF2, ORF3). ORF1 and ORF2 are homologous to sequences of waikaviruses, while ORF3 has no relatives in the databases. ORF1 encodes a putative polyprotein precursor that is putatively processed into eight smaller proteins, as in typical waikaviruses. Comprehensive analysis, including BLAST searches, genome organization and pairwise sequence comparisons, and phylogeny reconstructions, invariably placed the virus with the waikaviruses. Furthermore, due to lower amino acid sequence identity to known waikaviruses than the threshold species demarcation cutoff, this virus may represent a new species in the genus Waikavirus, family Secoviridae, and we have tentatively named it “camellia virus A” (CamVA). Finally, a field survey was conducted to assess the occurrence of CamVA in camellias and its associated symptoms.

З використанням двох різних процедур екстракції одержано вісім етанольних екстрактів із листя рослин Magnolia × soulangeana Soul.-Bod., Magnolia kobus та двох зразків Camellia japonica L. За допомогою високоефективної рідинної хроматографії, методу Фоліна—Чокальтеу і DPPH тесту вивчено склад та антиоксидантні властивості одержаних екстрактів. Показано, що основними складовими екстрактів магнолій є глікозиди кверцетину та похідні оксикоричних кислот, тоді як у екстрактах камелій переважають катехіни і похідні оксибензойних кислот. Склад екстрактів залежить не тільки від виду рослини, а й від способу екстрагування; загалом, екстракти, одержані при температурі 60 °С та під дією ультразвуку, мають більший вміст поліфенолів, ніж екстракти, отримані кип’ятінням рослинного матеріалу у 70 %-му етанолі при ~85 °C; загальна кількість фенольних сполук у екстрактах змінювалась у діапазоні 50—150 мг/л. Виявлено, що, попри значну різницю у вмісті фенолів, всі екстракти мають дуже високу антиоксидантну активність як у тесті Фоліна—Чокальтеу, так і в реакції з DPPH радикалами. Показано, що екстракти мають загальний фенольний індекс 1,5—7,5, а протягом 30 хв реакції сім з восьми екстрактів інгібують понад 50 % радикалів DPPH навіть після розведення у 10 разів. Екстракт камелії з найвищими антиоксидантними властивостями було протестовано як добавку до біодизелю, що має запобігти його окисненню під час зберігання. Стабільність біодизелю, одержаного з Camelina sativa (L.) Crantz, досліджували за прискореною процедурою при 43 °C протягом чотирьох тижнів, критерієм окиснення біопалива слугувало його кислотне число. Попередні результати показали, що екстракт камелії може бути ефективним антиоксидантним агентом — запобіжником окиснення біодизелю. Using two different extraction procedures, eight ethanol plants extracts are obtained from the leaves of Magnolia × soulangeana Soul.-Bod., Magnolia kobus, and two samples of Camellia japonica L. The composition and antioxidant properties of the extracts are studied by means of high performance liquid chromatography, the Folin— Ciocalteu method, and DPPH test. Hydroxycinnamic acids and quercetin glicosides are found to be the main constituents of Magnolia extracts, while hydroxybenzoic acids and catechin derivatives prevailed in Camelia extracts. The composition of the extracts was also affected by extraction procedures; in general, the extracts obtained at 60 °C under ultrasonic treatment contained phenolic compounds of a higher quantity than the extracts prepared by boiling the leaves in 70 % ethanol at ~85 °C; the overall amount of phenolic compounds in the extracts was in a range of 50-150 mg/l. In spite of significant distinctions in the content of phenols, all the extracts were found to possess a very high antioxidant activity in both Folin—Ciocalteu and DPPH assays. The extracts were found to have the total phenolic index of 1.5-7.5. During 30 min of the reaction, seven of eight extracts inhibited more than 50 % of DPPH radicals under standard test conditions, even being diluted by 10 times. The extract of Camellia japonica L. with the highest antioxidant ability was also tested as an additive to stabilize the biodiesel against oxidation. The stability of biodiesel prepared from Camelina sativa (L.) Crantz was studied according to accelerated procedure at 43 °C for four weeks, with the changes in the acid value of the samples being the criteria of fuel oxidation. The preliminary results showed that Camellia extract may be a promising stabilizing additive to reduce the biodiesel oxidation.

Camellia japonica L. is a flowering tree with several medicinal and cosmetic applications. Here, we investigated the efficacy of C. japonica placenta extract (CJPE) as a potential therapeutic agent for promotion of hair growth and scalp health by using various in vitro and in vivo assays. Moreover, we performed transcriptome analysis to examine the relative expression of human follicle dermal papilla cells (HFDPC) in response to CJPE by RNA‐sequencing (RNA‐seq). In vitro assays revealed upregulation of the expression of hair growth marker genes in HFDPC after CJPE treatment. Moreover, in vivo clinical tests with 42 adult female participants showed that a solution containing 0.5% CJPE increased the moisture content of the scalp and decreased the scalp's sebum content, dead scalp keratin, and erythema. Furthermore, RNA‐seq analysis revealed key genes in HFDPC which are associated with CJPE. Interestingly, genes associated with lipid metabolism and cholesterol efflux were upregulated. Genes upregulated by CJPE are associated with several hormones, including parathyroid, adrenocorticotropic hormone, α‐melanocyte‐stimulating hormone (alpha‐MSH), and norepinephrine, which are involved in hair follicle biology. Furthermore, some upregulated genes are associated with the regulation of axon guidance. In contrast, many genes downregulated by CJPE are associated with structural components of the cytoskeleton. In addition, CJPE suppressed genes associated with muscle structure and development. Taken together, this study provides extensive evidence that CJPE may have potential as a therapeutic agent for scalp treatment and hair growth promotion., Here, we examined the efficacy of C. japonica placenta extract (CJPE) as a potential therapeutic agent for promotion of hair growth and scalp health by using various in vitro and in vivo assays. Moreover, we conducted transcriptome analysis to examine the relative expression of human follicle dermal papilla cells in response to CJPE by RNA‐sequencing.

The species of the genus Camellia arise in southeast Asia, with 80 percent of the species coming from China. These include economically important C. sinensis (Tea) and C. oleifera (oil) and the decorative C. japonica, C. reticulata and C. sasanqua etc.As camellias had been cultivated for very long time, and had been developed as much popular throughout the world, a very large number of camellias had been cultivated. So far, over 23,000 cultivars, with nearly 45,000 cultivar names including synonyms, have been registered or published. In order to strengthen the system of validity by prior publication, prevent further duplication when selecting names for new cultivars, and assist in clearing up some of the confusion that still clings to a few of the old cultivar names, it is urgently needed to have a dataset to include all camellia cultivars in the long history throughout the world.The camellia cultivar Names were widely collected from books and journals and new registrations through the world, and reviewed by experts in the online working platform, the Database of International Camellia Register. After treating some important issues existed in camellia names, especially those plenty of re-used names and diacritical marks etc. in Japanese cultivars, a dataset of Camellia names was summarized from the year of 1253 to 2019 throughout the world (Table 1). So far totally 45,210 cultivar names were released by different countries, including 23,887 accepted names and 21,323 synonyms or other names. Excluding 3,944 names believed extinct, totally 19,944 cultivar names are present used. Among camellia cultivars, most of them (23,449) were for ornamental, 429 for tea, 228 for oil. Most cultivars (ca. 76.10%) were from C. japonica and its hybrids (19,050), around 5.73% cultivars were from C. sasanqua and its hybrids (1,434), and about 5.72% were from C. reticulata and its hybrids (1,432). Top five origin countries are USA (7,502 cultivars), Japan (6,592), Italy (2,833), China (2,066) and Australia (1,216). After analyzing the relationship of cultivar numbers in different years and countries, the development history of Camellia had close related with those of countries in the world. It is the most comprehensive dataset in the genus Camellia throughout the world managed by International Camellia Registration team, which will facilitate quick reference and scientific naming for breeders, and utilization of camellias through the Belt and Road Initiative.

In Camellia japonica callus culture, the effects of light quality on the accumulation of phenolic compounds were examined. To this end, the calli were cultured under three monochrome [white (W), red (R), and blue (B)] and two mixed [red/blue (RB) and red/green/blue (RGB)] light sources. After 4 weeks of culture, fresh and dry callus weights were determined, and phenolic content was analyzed using high-performance liquid chromatography. We also examined the effects of RGB light on calli derived from four origins (leaf: CL; root: CR; petal: CP; and ovary: CO). Total phenolic and flavonoid content and DPPH radical scavenging activity were highest in calli exposed to RB and RGB. Catechin was detected only in calli exposed to mixed light (RB and RGB). Interestingly, red pigmentation development in CL and CR calli after 2 weeks of culture and organogenic calli in CR and CP samples was observed. Furthermore, expression of the phenylalanine ammonia lyase and chalcone synthase genes was found to be higher in the CR line than in other lines, and total phenolic and flavonoid content was also higher in the CR and CP lines. The findings of the present study revealed that the accumulation of phenolics and flavonoids in callus tissue varies depending on light quality, which stimulates cell division, and may thus affect the proliferation and organogenesis of C. japonica callus. We also established that the effects of light on red pigment expression and the accumulation of bioactive compounds are dependent on the tissue origin of callus material.

The family Sclerotiniaceae includes important phytopathogens, such as Botrytis cinerea and Sclerotinia sclerotiorum, that activate plant immune responses to facilitate infection propagation. The mechanisms of plant resistance to these necrotrophic pathogens are still poorly understood. To discover mechanisms of resistance, we used the Ciborinia camelliae (Sclerotiniaceae)–Camellia spp. pathosystem. This fungus induces rapid infection of the blooms of susceptible cultivar Nicky Crisp (Camellia japonica × Camellia pitardii var. pitardii), while Camellia lutchuensis is highly resistant. Genome-wide analysis of gene expression in resistant plants revealed fast modulation of host transcriptional activity 6 h after ascospore inoculation. Ascospores induced the same defense pathways in the susceptible Camellia cultivar but much delayed and coinciding with disease development. We next tested the hypothesis that differences in defense timing influences disease outcome. We induced early defense in the susceptible cultivar using methyl jasmonate and this strongly reduced disease development. Conversely, delaying the response in the resistant species, by infecting it with actively growing fungal mycelium, increased susceptibility. The same plant defense pathways, therefore, contribute to both resistance and susceptibility, suggesting that defense timing is a critical factor in plant health, and resistance against necrotrophic pathogens may occur during the initial biotrophy-like stages.

Plants of the genus Camellia are widely cultivated throughout the world as ornamentals because of their bright and large flowers. The widely cultivated varieties are mainly derived from the mutant lines and hybrid progenies of Camellia japonica Linn. and Camellia reticulata Lindl. While their geographical distributions and environmental adaptabilities are significantly different, no systematic comparison has been conducted between these two species. To investigate differences in how these plants have adapted to their environments, we measured photosynthesis and 20 leaf functional traits of C. japonica and C. reticulata grown under the same conditions. Compared with C. japonica, C. reticulata showed higher values for light saturation point, light-saturated photosynthetic rate, leaf dry mass per unit area and stomatal area, but lower values for apparent quantum efficiency, leaf size, stomatal density and leaf nitrogen content per unit mass. Stomatal area was positively correlated with light-saturated photosynthetic rate and light saturation point, but negatively correlated with stomatal density. The differences between C. reticulata and C. japonica were mainly reflected in their adaptations to light intensity and leaf morphological traits. C. reticulata is better adapted to high light intensity than C. japonica. This difference is related to the two species' differing life forms. Thus, leaf morphological traits have played an important role in the light adaptation of C. reticulata and C. japonica, and might be first noticed and selected during the breeding process. These findings will contribute to the cultivation of camellia plants.

One large contig with high sequence similarity to Asian prunus virus 2 was identified by high-throughput sequencing from a camellia (Camellia japonica) tree with ringspot symptoms. The complete genome of this new virus was determined to be 8829 nucleotides long, excluding the 3' poly(A) tail. Its genome organization resembles that of known foveaviruses but contains an additional open reading frame in the 3'-terminal region. Phylogenetic analysis also places this virus with members of the genus Foveavirus in the family Betaflexiviridae in the same subgroup. The virus, which is provisionally named "camellia ringspot-associated virus 4″, shares 50-56% nucleotide sequence identity with other foveaviruses and should represent a new species in the genus.

This study aimed to screen for plants with antimicrobial potential among the evergreen woody species of South Korea that are used for horticulture and landscaping and to provide basic information about plants with proven antimicrobial activity to underpin future research. The plant materials were extracted under various conditions, and the antimicrobial activities of the extracts were evaluated by agar diffusion assay. The screening tests demonstrated that the crude extracts of 43 species had inhibitory effects against S. aureus. The inhibitory activities of four species (Elaeocarpus sylvestris, Camellia japonica, Cleyera japonica, and Quercus salicina) were relatively higher than that of the synthetic antimicrobial agents methylparaben and phenoxyethanol. The highest inhibitory activity was observed with the leaf extracts (extracted with methanol for 30 minutes) of E. sylvestris, based on induction of the largest inhibition zone of 23.3 mm in size. In addition, solvent fractions of E. sylvestris were evaluated. The largest inhibitory zone of 23.1 mm was observed for the n-butanol fraction, which is likely to contain effective compounds that exhibit inhibitory activity against S. aureus. In contrast, n-hexane and residual aqueous fractions showed no antimicrobial activity. Overall, our findings confirm that evergreen woody plants native to South Korea have potential antimicrobial activity.

В статье приводится краткое описание анемоновидных сортов камелии японской, которое включает: форму цветка, окраску, размер, сроки цветения, форму кроны, а также параметры листьев., The article provides a brief description of anemone-like varieties of Japanese camellia, which includes: flower shape, color, size, flowering time, crown shape, as well as leaf parameters.

Frogs can be added to a list of different raw materials which have sustainable economic value to their producers. Therefore, the biochemical attributes of the frogs require further scientific scrutiny. The major objective of the current study is to investigate some biochemical compositions of edible portions of Pelophylax ridibundus (Pallas, 1771) grown in different conditions. The wild frogs, semicultured frogs, and cultured frogs were investigated regarding female and male specimens, leading to six groups that were determined to investigate the biochemical features of frogs. The results show that they (all frogs in all six groups) have low lipid contents (p < 0.05). The protein contents of the frogs varied in the range of 10.54%–16.10%. The lowest ash contents were found in semicultured male and female frogs. The average moisture contents were roughly 80% for all specimens. The major fatty acids were C16:0, C18:0, C18:1n9, C18:2n6, and C20:4n6 for wild, semicultured, and cultured frogs, respectively, for both sexes, showing their respective amounts varied among groups. All in all, the results show that there exist some differences in the nutritional content of frogs grown in different conditions in terms of the analyzed parameters.

Negative air ion (NAI) has been widely recognized to be regulated by plant photosynthesis. However, their quantified relationship had seldom been validated. In this study, plant photosynthesis-related traits (including leaf area-specific photosynthesis An, transpiration rates El, stomatal conductance gs, photosynthetic electron transport rate ETR) and leaf area-specific NAI (NAIc) were measured to qualify their relations with ten different species in a thermostat. Sap flow measurement was conducted on 15 individuals of Camellia japonica L. in an open-top chamber (OTC) to inverse sap flow based-stomatal conductance (GSf), as a proxy of whole individual photosynthesis. We also conducted gas exchange measurements on these individuals and compared them with their GSf. Three micro-meteorological parameters, including air temperature (Ta), relative humidity (RH) and radiation (Ra) and NAI were synchronously monitored with sap flow measurement. Significant differences were observed in NAIc among the 10 species, and was highly determined by their An, El and gs. However, since RH in the thermostat was stable at 70%, we could concluded that the NAIc difference among species was determined by the gs-related photosynthesis, rather than the El- related transpiration. In the OTC experiment, before the C. japonica individuals were moved in, Ta, RH and Ra accounted for 89% of the total NAI variation. However, after the C. japonica were moved in, the contribution of the three parameters decreased to 40%, and the new model only provided 46% of NAI variation. Since gs and An of C. japonica individuals were well explained by the GSf (R2 = 0.94 and 0.91 respectively), which proved GSf a good proxy of gs and An. GSf during the daytime was then considered in the model, and 76.88% of NAI variances were accounted. Even though some limitations such as the disturbance of air quantity index (AQI) still exist in our study, we provided a more efficient way to inverse the NAI dynamics in the region of vegetation.

CBFs belong to the ERF subfamily of the AP2 supergene family and often play an important role in the cold acclimation of temperate plants. However, the role of CBFs in Camellia japonica (Naidong), the only Camellia japonica population found in the temperate zones of China, remains unclear. It is very important to study the genetic composition of C. japonica (Naidong) to adapt to low temperature for Camellia species. Using full-length transcriptome data, we identified four CjCBF genes that respond to cold stress and analyzed their evolutionary relationships, domains, and expression patterns. The phylogeny of CBFs of 19 angiosperms divided the genes into three categories, and the four CjCBFs belong to a small subcluster. The strong response of CjCBF1 to cold treatment and its sustained high level of expression indicated that it plays an important role in the process of cold acclimation. A yeast two-hybrid assay revealed an interaction between CjCBF1, CjCBF2, and CjCBF5, and subcellular localization confirmed this finding. The expression of CjCBFs was tissue-specific: CBF1 was mainly expressed in leaves, and CBF3 was mainly expressed in stem. The responses of the four CjCBFs to drought and high temperature and the effect of light were also characterized. Our study provides new insight into the role of CBFs in the cold response in C. japonica (Naidong).

Bird pollination can vary spatially in response to spatial fluctuations in flowering even within plant populations. In this study, we examined the hypothesis that the spatial variation in bird pollination may induce mitigating effects, which maintains or increases genetic diversity of pollen pools at local sites with low flowering densities. To test this hypothesis, we analyzed the landscape-level genetic effects within a population of Camellia japonica on the pollen pools accepted by individuals in two reproductive years by using genotypes at eight microsatellite loci of 1323 seeds from 19 seed parents. Regression analyses using the quadratic models of correlated paternity between pollen pools against spatial distances between the seed-parent pairs revealed not only local pollination but also some amount of long-distance pollen dispersal. The genetic diversity of pollen pools accepted by seed parents tended to be negatively related to the densities of flowering individuals near the seed parents during winter (when the effective pollination of C. japonica is mediated mostly by Zosterops japonica). We show that the low density of flowering individuals may induce the expansion of the foraging areas of Z. japonica and consequently increase the genetic diversity of pollen pools. This spatial variation in bird pollination may induce the mitigating effects on the C. japonica population. The comparisons between the two study years indicate that the overall pattern of bird pollination and the genetic effects described here, including the mitigating effects, may be stable over time., ファイル公開：2020/07/01

The aim of this study was to compare the two in vitro culture systems callus and adventitious root by investigating the biomass and phenolic compounds in calli and adventitious roots induced from four different explants (leaf, root, petal, and ovary) in Camellia japonica. The biomass of calli and adventitious roots was examined after 4 and 8 weeks of cultivation, respectively, and 22 phenolic compounds were analyzed using high-performance liquid chromatography (HPLC). The biomass of the ovary-derived calli (2.0 g･mass-1) was 1.5-fold that of the leaf-derived calli. The dry weight (DW) was highest in ovary-derived calli; however, the highest dry matter content was obtained from leaf-derived calli. Differences in the investigated characteristics depended on the callus origin. In adventitious roots, the highest biomass was achieved in the leaf-derived adventitious root system; its fresh weight was 2.3-fold (89 mg･ea-1) higher, and its DW was 1.8-fold (16 mg･ea-1) higher than those of ovary-derived adventitious root system. Active cell division was detected in petal-derived lines in both the calli and adventitious roots. Results of the HPLC analysis revealed that the total content of 22 phenolic compounds was highest in ovary-derived calli and ovary-derived adventitious roots. Our experiments confirmed that the calli and adventitious roots of C japonica have different cytological characteristics and bioactive compounds depending on the explant origin. In addition, callus culture was a more suitable system than adventitious root for producing phenolic compounds when the duration of the culture period and biomass were considered.

Fruit patterning involves the cooperation of multiple processes, including metabolic change, cell differentiation, and cell expansion. The FRUITFUL (FUL) and SHATTERPROOF1/2 (SHPs) MADS-box genes are master regulators directing fruit patterning in several eudicots. However, the regulatory mechanisms of the FUL–SHP network in different fruit types remain unclear. Here, we characterized the functions of an ortholog (CjPLE) of SHPs from Camellia japonica. We showed that CjPLE was predominantly expressed in stamen and carpel tissues during the early stage of floral development and that transcripts were abundant in the pericarp tissues during fruit development. The ectopic expression of CjPLE in Arabidopsis caused enhanced development of the carpels, whereas no defects in floral identity were observed. To investigate the downstream targets of CjPLE, overexpression transformants were analysed through a callus transformation system in Camellia azalea. We examined the expression levels of potential downstream target genes and found that two previously identified APETALA1-like genes (CjAPL1/2) were significantly up-regulated. We showed that CjPLE directly bound to the CArG motifs in the promoter region of CjAPL1 (the FUL ortholog). Taken together, our results reveal a possible positive regulation of FUL by SHP in the control of fruit development in Camellia.

Camellia japonica bee pollen is one of the major types of bee pollen in China and exhibits antioxidant and anti-inflammatory activities. The aims of our study were to evaluate the effects and the possible mechanism of Camellia japonica bee pollen polyphenols on the treatment of hyperuricemia induced by potassium oxonate (PO). The results showed that Camellia japonica bee pollen ethyl acetate extract (CPE-E) owned abundant phenolic compounds and strong antioxidant capabilities. Administration with CPE-E for two weeks greatly reduced serum uric acid and improved renal function. It inhibited liver xanthine oxidase (XOD) activity and regulated the expression of urate transporter 1 (URAT1), glucose transporter 9 (GLUT9), organic anion transporter 1 (OAT1), organic cation transporter 1 (OCT1) and ATP-binding cassette superfamily gmember 2 (ABCG2) in kidneys. Moreover, CPE-E suppressed the activation of the toll-like receptor 4/myeloid differentiation factor 88/nuclear factor-κB (TLR4/MyD88/NF-κB) signaling pathway and nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome in PO-treated mice, and related inflammatory cytokines were reduced. CPE-E also modulated gut microbiota structure, showing that the abundance of Lactobacillus and Clostridiaceae increased in hyperuicemic mice. This study was conducted to explore the protective effect of CPE-E on hyperuricemia and provide new thoughts for the exploitation of Camellia japonica bee pollen.

Camellia japonica petals are colorful, rich in anthocyanins, and possess important ornamental, edible, and medicinal value. However, the regulatory mechanism of anthocyanin accumulation in C. japonica is still unclear. In this study, an integrative analysis of the metabolome and transcriptome was conducted in five C. japonica cultivars with different petal colors. Overall, a total of 187 flavonoids were identified (including 25 anthocyanins), and 11 anthocyanins were markedly differentially accumulated among these petals, contributing to the different petal colors in C. japonica. Moreover, cyanidin-3-O-(6″-O-malonyl) glucoside was confirmed as the main contributor to the red petal phenotype, while cyanidin-3-O-rutinoside, peonidin-3-O-glucoside, cyanidin-3-O-glucoside, and pelargonidin-3-O-glucoside were responsible for the deep coloration of the C. japonica petals. Furthermore, a total of 12,531 differentially expressed genes (DEGs) and overlapping DEGs (634 DEGs) were identified by RNA sequencing, and the correlation between the expression level of the DEGs and the anthocyanin content was explored. The candidate genes regulating anthocyanin accumulation in the C. japonica petals were identified and included 37 structural genes (especially CjANS and Cj4CL), 18 keys differentially expressed transcription factors (such as GATA, MYB, bHLH, WRKY, and NAC), and 16 other regulators (mainly including transporter proteins, zinc-finger proteins, and others). Our results provide new insights for elucidating the function of anthocyanins in C. japonica petal color expression.

Medicinal plants have been used since antiquity to cure illnesses and injuries. In the last few decades, natural compounds extracted from plants have garnered the attention of scientists and the Camellia species are no exception. Several species and cultivars are widespread in Asia, namely in China, Japan, Vietnam and India, being also identified in western countries like Portugal. Tea and oil are the most valuable and appreciated Camellia subproducts extracted from Camellia sinensis and Camellia oleifera, respectively. The economic impact of these species has boosted the search for additional information about the Camellia genus. Many studies can be found in the literature reporting the health benefits of several Camellia species, namely C. sinensis, C. oleifera and Camellia japonica. These species have been highlighted as possessing antimicrobial (antibacterial, antifungal, antiviral) and antitumoral activity and as being a huge source of polyphenols such as the catechins. Particularly, epicatechin (EC), epigallocatechin (EGC), epicatechin-3-gallate (ECG), and specially epigallocatechin-3-gallate (EGCG), the major polyphenols of green tea. This paper presents a detailed review of Camellia species’ antioxidant properties and biological activity.