<Emphasis Type="Italic">Camellia cattienensis</Emphasis>: a new species of <Emphasis Type="Italic">Camellia</Emphasis> (sect. <Emphasis Type="Italic">Archaecamellia</Emphasis>: Theaceae) from Vietnam

A new species of the genus Camellia L. (Theaceae, Theoideae) is described and illustrated under the name C. cattienensis. This species occurs in the rainforest vegetation of Lam Dong Province, Vietnam. A discussion of the morphological characters distinguishing this new species from related Camellia species is presented. Morphological evidence supports a transitional taxonomic placement in Camellia sect. Archaecamellia Sealy. This placement is justified by C. cattienensis exhibiting some morphological characteristics also found in sects Stereocarpus (Pierre) Sealy and Piquetia (Pierre) Sealy.     

Leaf morphology and anatomy of Camellia section Camellia (Theaceae)

The delimitations of species in Camellia section Camellia have been disputed for many years, resulting from uncertain relationships among species. Leaf morphological and anatomical characters for 54 species and three varieties in this section were investigated to reveal the relationships. Principal component analysis and cluster analysis were conducted using the transformed data for quantitative and qualitative characters from leaf morphology and anatomy. Combining the results of statistical analysis with comparative leaf characters of morphology and anatomy, we discussed the taxonomic treatment of section Camellia by Chang compared with that of Ming and we conclude that section Camellia consists of c. 50 species. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 456–476.     

Camellia curryana and C. longii spp. nov. (Theaceae) from Vietnam

Two species of Camellia L. (Theaceae) are described here as new: C. curryana and C. longii. The new species were discovered in the southern Annamite Mountains of Vietnam and are endemic to tropical rainforest remnants that occur at altitudes between 1500 and 1700 m a.s.l. Camellia curryana possesses almost sessile, unevenly circular, two whorled, white‐cream and proximally yellowish flowers, proximally joined outer stamens, three styles and mature fruit that dehisces into three parts, or longitudinally into two halves. Camellia longii has campanulate or almost campanulate, intensely dark orange to red flowers with uneven whitish margins, 5–6 petals and 3–2 petaloids, filaments that are united with the petals and one another, a diamond shaped ovary and compound 5–6 styles that are connate at the base.     

Unravelling Diaporthe species associated with Camellia

The genus Diaporthe (syn. Phomopsis) comprises important pathogens, endophytes or saprobes with diverse host associations and worldwide distribution. Phomopsis theae is the first and hitherto the only recorded Diaporthe species on Camellia in China. The aim of this study was to investigate the Diaporthe species associated with symptomatic and asymptomatic tissues of Camellia spp. from several provinces in China. Eighty-three strains were isolated in the present study. Based on the multi-locus (ITS, HIS, TEF1, TUB) phylogenetic analyses and phenotypic characters, four novel species (D. apiculata Y.H. Gao & L. Cai, D. compacta Y.H. Gao & L. Cai, D. oraccinii Y.H. Gao & L. Cai, D. penetriteum Y.H. Gao & L. Cai), and three known species (D. discoidispora, D. hongkongensis, D. ueckerae) were identified. Five strains were assigned to D. amygdali species complex and 17 strains to D. eres species complex respectively, but they could not be further identified to species level using current multi-locus phylogenetic analysis and morphological characters. Of the identified species, D. compacta and D. discoidispora are only known as endophytes. Diaporthe hongkongensis is the dominant species on Camellia, accounting for 53.3% of the frequency of occurrence. Diaporthe lithocarpus is synonymized with D. hongkongensis; D. miriciae is synonymized with D. ueckerae. Our study revealed a high diversity of undescribed Diaporthe species on Camellia.     

Concerted and birth-and-death evolution of 26S ribosomal DNA in Camellia L.

Background and AimsThe ribosomal DNA (rDNA) gene family, encoding ribosomal RNA (rRNA), has long been regarded as an archetypal example illustrating the model of concerted evolution. However, controversy is arising, as rDNA in many eukaryotic species has been proved to be polymorphic. Here, a metagenomic strategy was applied to detect the intragenomic polymorphism as well as the evolutionary patterns of 26S rDNA across the genus Camellia.MethodsDegenerate primer pairs were designed to amplify the 26S rDNA fragments from different Camellia species. The amplicons were then paired-end sequenced on the Illumina MiSeq platform.Key ResultsAn extremely high level of rDNA polymorphism existed universally in Camellia. However, functional rDNA was still the major component of the family, and was relatively conserved among different Camellia species. Sequence variations mainly came from rRNA pseudogenes and favoured regions that are rich in GC. Specifically, some rRNA pseudogenes have existed in the genome for a long time, and have even experienced several expansion events, which has greatly enriched the abundance of rDNA polymorphism.Conclusions Camellia represents a group in which rDNA is subjected to a mixture of concerted and birth-and-death evolution. Some rRNA pseudogenes may still have potential functions. Conversely, when released from selection constraint, they can evolve in the direction of decreasing GC content and structural stability through a methylation-induced process, and finally be eliminated from the genome.     

Comparative Chloroplast Genomes of Camellia Species

Background

Camellia , comprising more than 200 species, is a valuable economic commodity due to its enormously popular commercial products: tea leaves, flowers, and high-quality edible oils. It is the largest and most important genus in the family Theaceae. However, phylogenetic resolution of the species has proven to be difficult. Consequently, the interspecies relationships of the genus Camellia are still hotly debated. Phylogenomics is an attractive avenue that can be used to reconstruct the tree of life, especially at low taxonomic levels.

Methodology/Principal Findings

Seven complete chloroplast (cp) genomes were sequenced from six species representing different subdivisions of the genus Camellia using Illumina sequencing technology. Four junctions between the single-copy segments and the inverted repeats were confirmed and genome assemblies were validated by PCR-based product sequencing using 123 pairs of primers covering preliminary cp genome assemblies. The length of the Camellia cp genome was found to be about 157kb, which contained 123 unique genes and 23 were duplicated in the IR regions. We determined that the complete Camellia cp genome was relatively well conserved, but contained enough genetic differences to provide useful phylogenetic information. Phylogenetic relationships were analyzed using seven complete cp genomes of six Camellia species. We also identified rapidly evolving regions of the cp genome that have the potential to be used for further species identification and phylogenetic resolution.

Conclusions/Significance

In this study, we wanted to determine if analyzing completely sequenced cp genomes could help settle these controversies of interspecies relationships in Camellia . The results demonstrate that cp genome data are beneficial in resolving species definition because they indicate that organelle-based “barcodes”, can be established for a species and then used to unmask interspecies phylogenetic relationships. It reveals that phylogenomics based on cp genomes is an effective approach for achieving phylogenetic resolution between Camellia species.     

Polyspora huongiana sp. nov. (Theaceae) from Vietnam and notes on related species

A new species of Polyspora Sweet (Theaceae) endemic to the Bidoup‐Nui Ba National Park, Lam Dong Province, Vietnam, is described and illustrated: Polyspora huongiana Orel, Curry & Luu. The newly described species has variably shaped, coriaceous, narrowly elliptical leaves, terminal, pedicellate, mostly solitary, rather fleshy, dark pink to red flowers, with petals in two whorls; a columnar, seamlessly fused style with 3–5 apical lobes; persistent bracteoles; and a superior 3–4 (–5) chambered ovary. The morphological evidence supports taxonomic placement in the genus Polyspora. A new name is provided and new combinations are made for some other species in the region.     

Phylogenetics of global Camellia (Theaceae) based on three nuclear regions and its implications for systematics and evolutionary history

Camellia contains tea, oil camellia, and camellias which benefit people globally. Its infrageneric classification is, however, controversial and unstable, and former phylogenetic analyses failed to yield robust and consistent trees. Here, we aimed to reconstruct a robust phylogenetic tree, date all clades and discuss the evolutionary history of Camellia. Emphasizing the taxonomically comprehensive sampling rather than more DNA data, orthologous nuclear RPB2 introns 11–15 and 23, and waxy were sequenced for 99 taxa of Camellia to reconstruct its phylogenetic history. Ten clades are identified in Camellia: Camellia II, Camelliopsis, Corallina, Furfuracea, Heterogenea, Paracamellia, Piquetia, Stereocarpus, Thea and Yellow camellias II. Camellia grijsii and C. shensiensis are not closely related with other oil camellias that form the clade Paracamellia. Sections Camelliopsis and Theopsis together form the clade Camelliopsis, while clade Furfuracea consists of sect. Furfuracea and C. hongkongensis. Camellia connata is separated from C. lanceolata but nested in the clade Heterogenea, and C. longissima is nested in the clade Thea, suggesting a new germplasm for tea breeding. Molecular dating using four fossil calibration points suggests that the crown age of Camellia is 39.5 Ma with clade Corallina probably the earliest infrageneric clade to diversify and the most widespread clade, Paracamellia, the latest. Our findings provide new insights into the phylogenetic relationships, systematics and evolutionary history of Camellia.     

<Emphasis Type="Italic">Camellia nanningensis</Emphasis> sp. nov.: the earliest fossil wood record of the genus <Emphasis Type="Italic">Camellia</Emphasis> (Theaceae) from East Asia

A new species Camellia nanningensis was described on the basis of well-preserved mummified wood from the upper Oligocene Yongning Formation of Nanning Basin in Guangxi Province, South China. This represents the most ancient fossil wood assigned to Camellia, and the earliest fossil record of the family Theaceae in China. This fossil material shows that Camellia occurred in China as early as the late Oligocene, suggesting more ancient radiation of this genus than estimated by molecular dating.     

Taxonomic treatments of Camellia (Theaceae) species with secretory structures based on integrated leaf characters

Multivariate analysis of leaf shape, anatomy, and Fourier-transform infrared (FTIR) data of 27 Camellia species with secretory structures (sects. Archecamellia, Stereocarpus, Furfuracea, Chrysantha), together with three species from related genera, Gordonia and Tutcheria (Theacea), was conducted to clarify some taxonomic problems. Our results show that crystals occurring in adaxial epidermal cells are firstly observed in Chrysantha species, and the secretory structures described are in fact cork warts. Furthermore, we introduce a form coefficient (F _c) to assess the shape of epidermal cells, since they are usually irregular and difficult to describe. Pearson correlation analysis indicates that F _c is useful to assess epidermal cell shape. Principal component analysis (PCA) of leaf shape indicates that two species from section Archecamellia and two species from section Stereocarpus are significantly different from those in section Furfuracea. Cluster analysis of FTIR data visualizes the degree of affinity among the 30 species examined here, which is consistent with the cluster analysis (CA) of anatomical data, as illustrated in the dendrogram. Therefore, our study indicates that integrated leaf characters based on leaf shape, anatomy, and FTIR data are useful in the taxonomic treatment of Camellia species with secretory structures. Taxonomic controversies among the Camellia species with secretory structures could thus be successfully addressed using only a few intact or small portions of leaves. Moreover, our results tend to support that Chrysantha species should not be merged into section Archecamellia, and that section Heterogenea should not be recognized in taxonomic treatments of Camellia species with secretory structures.     

Chemical Studies of Camellia Family

In the course of chemotaxonomical works of Camellia family, a new phenolic substance was found in the methanol extract of the young leaves of Cleyera ochnaceae D. C. This was named “Sakakin” which is a glycoside composed of orcinol and d-glucose. The structure was proved to be 3-hydroxy-5-β-d-glucopyranosidoxy-toluene, and has been confirmed by synthesis.     

Co-occurrence of Pseudocercospora species and rhytismatalean ascomycetes on maple and camellia in Taiwan

A new species of Pseudocercospora on leaves of Acer albopurpurascens, a maple endemic to Taiwan, is described. The fungus sporulated on leaf spots caused by Vladracula annuliformis (Rhytismatales). Pseudocercospora camelliicola and Coccomyces sinensis on leaves of Camellia cultivars are recorded for the first time for Taiwan and described and illustrated in detail. In contrast to the situation on maple, both fungal species on camellia caused conspicuous breakage of the epidermis during sporulation, which is discussed in connection with fungal succession during leaf litter decomposition.     

Isolation and characterization of 15 microsatellite markers from wild tea plant (Camellia taliensis) using FIASCO method

Camellia taliensis is one of the most important wild tea plants in China, especially in Yunnan Province. In this study, we described the development of 15 microsatellite markers from the genome of C. taliensis using the protocol of fast isolation by AFLP of sequences containing repeats (FIASCO). Polymorphism of each locus was assessed in 24 samples collected from six wild populations of C. taliensis. The average allele number of the microsatellites was four per locus, ranging from 2 to 7. The observed and expected heterozygosities varied from 0.076 to 0.5833 and from 0.1560 to 0.6917, respectively. Cross-species amplification in other three tea plants showed eleven of them holding promise for sister species. These polymorphic SSR markers would be useful tools for population genetics studies and assessing genetic variations to establish conservation strategy, molecular identification and molecular breeding on this tea plant and its allied species and varieties in section Thea genus Camellia.     

A Contribution to the Pollen Morphology of Camellia (Theaceae)

The pollen morphology and ultrastructure of 20 species of Camellia (Theaceae) representing the four subgenera were examined. The pollen is tricolporate, spherical to slightly oblate or prolate, with scabrate to rugulate exine sculpturing. The tectum is traversed by perforations that vary in diameter. Pollen wall structure is tectate-columellate, the columellae fused to a footlayer. Endexine is present in all of the taxa examined. The greatest variation was observed in pollen size.     

Saussurea baoxingensis sp. nov. (Compositae,Cardueae) from Sichuan,China

Saussurea baoxingensis Y. S. Chen (Compositae, Cardueae), a new species of snow lotus from the Sichuan province, China is described and illustrated. It belongs to subgenus Amphilaena and is allied to S. muliensis. Morphological characteristics that distinguish the new species from S. muliensis are presented and discussed.     

石灰土和酸性土生境下金花茶组植物叶片钙形态差异

为探究不同生境下金花茶组植物的叶片钙形态特征，该研究以10种石灰土生境和4种酸性土生境的金花茶为对象，测定了其生境土壤的钙含量和pH值，以及该生境下金花茶组植物叶中的硝酸钙和氯化钙、水溶性有机酸钙、果胶酸钙、磷酸钙和碳酸钙、草酸钙、硅酸钙和总钙的含量。结果表明：(1)石灰土生境的土壤钙含量和土壤pH均极显著(P<0.01)高于酸性土。(2)在石灰土生境中，金花茶组植物的叶钙形态以草酸钙(41.17%)为主，而在酸性土生境中则以果胶酸钙(43.10%)为主，除硝酸钙和氯化钙、果胶酸钙外，石灰土金花茶的各叶钙形态和总钙含量均极显著(P<0.01)高于酸性土金花茶。(3)相关性分析结果显示，大部分叶钙形态含量与土壤pH和土壤钙含量呈极显著(P<0.01)正相关，表明土壤环境对金花茶组植物叶钙形态特征具有重要影响。(4)单因素方差分析结果显示，各叶钙形态含量在物种间存在极显著(P<0.01)差异，表明金花茶组植物在物种分化过程中叶钙形态特征具有多样性。(5)基于叶钙形态特征的聚类分析显示，14种金花茶可归为3大类。总体而言，不同生境背景下金花茶组植物的叶钙形态差异可能是...     

Biosynthesis of Purine Alkaloids in Camellia Plants

The metabolism of [8-¹⁴C]adenine and [8-¹⁴C]hypoxanthine infour species of Camellia plants was investigated in relationto the synthesis of purine alkaloids, caffeine and theobromine.Young leaves of C. sinensis had the ability to synthesize caffeine,but in C. irrawadiensis, these labelled precursors were incorporatedinto theobromine, not caffeine. No synthesis of purine alkaloidscould be detected in C. japonica and C. sasanqua leaves. Conventional"salvage" and degradation pathways of purines were present inall species of Camellia plants examined. ¹ Present address: Research Center, Mitsubishi Chemical IndustriesLtd., 1000 Kamisida-cho, Midori-ku, Yokohama, 227 Japan. (Received September 29, 1986; Accepted January 22, 1987)