Genus Cornus Research Articles

Therapeutic Potential of Cornus Genus: Navigating Phytochemistry, Pharmacology, Clinical Studies, and Advanced Delivery Approaches.

The genus Cornus (Cornaceae) plants are widely distributed in Europe, southwest Asia, North America, and the mountains of Central America, South America, and East Africa. Cornus plants exhibit antimicrobial, antioxidative, antiproliferative, cytotoxic, antidiabetic, anti-inflammatory, neuroprotective and immunomodulatory activities. These plants are exploited to possess various phytoconstituents such as triterpenoids, iridoids, anthocyanins, tannins and flavonoids. Pharmacological research and clinical investigations on various Cornus species have advanced significantly in recent years. Over the past few decades, a significant amount of focus has also been made into developing new delivery systems for Cornus mas and Cornus officinalis. This review focuses on the morphological traits, ethnopharmacology, phytochemistry, pharmacological activities and clinical studies on extracts and active constituents from plants of Cornus genus. The review also highlights recent novel delivery systems for Cornus mas and Cornus officinalis extractsto promote sustained and targeted delivery in diverse disorders. The overwhelming body of research supports the idea that plants from the genus Cornus have therapeutic potentialand can be investigated in the future for treatingseveral ailments.

Characteristics and phylogenetic analysis of the complete chloroplast genome of Cornus hongkongensis Hemsl. 1888 (Cornaceae)

Cornus hongkongensis Hemsl. 1888, native to Hong Kong, belongs to the subgenus Syncarpea within the Cornus genus of the Cornaceae family. The complete chloroplast genome of C. hongkongensis spans 156,954 bp, comprising four subregions: a large single-copy region (86,290 bp), a small single-copy region (18,394 bp), and a pair of inverted repeats (26,135 bp). Within the chloroplast genome of C. hongkongensis, we identified 113 unique genes, including 80 protein-encoding genes, four ribosomal RNA (rRNA) genes, and 30 transfer RNA (tRNA) genes. Phylogenetic analysis based on the complete chloroplast genome of 30 related taxa of the Cornus genus indicates that C. hongkongensis has not formed a monophyletic lineage. Analyses of sequence divergence found three intergenic regions including rps19-rpl22, ccsA-ndhD, and atpH-atpI, exhibiting a high degree of variations. The first chloroplast genome of C. hongkongensis was reported in this work contributes to the enrichment of genomic data for the genus Cornus.

Karyotype evolution of the Asterids insights from the first genome sequences of the family Cornaceae.

Cornaceae is a core representative family in Cornales, the earliest branching lineage in the Asterids on the life tree of angiosperms. This family includes the only genus Cornus, a group of ~55 species. These species occur widely in Northern Hemisphere and have been used as resources for horticultural ornaments, medicinal and industrial manufacturing. However, no any genome sequences are available for this family. Here, we reported a chromosome-level genome for Cornus controversa. This was generated using high-fidelity plus Hi-C sequencing, and totally ~771.80 Mb assembled sequences and 39,886 protein-coding genes were obtained. We provided evidence for a whole-genome duplication event (WGD) unique to C. controversa. The evolutionary features of this genome indicated that the expanded and unique genes might have contributed to response to stress, stimulus and defense. By using chromosome-level syntenic blocks shared between eight living genomes, we found high degrees of genomic diversification from the ancestral core-eudicot genome to the present-day genomes, suggesting an important role of WGD in genomic plasticity that leads to speciation and diversification. These results provide foundational insights on the evolutionary history of Cornaceae, as well as on the Asterids diversification.

New data on the genus Cornus L. (Cornaceae) in the Bulgarian Miocene flora

New data on the distribution of species of the genus Cornus on the territory of Bulgaria during the Miocene are presented. The species C. megaphylla was found for the first time in the middle Miocene flora from Satovcha (SW Bulgaria). So far, this species has been established in the middle Miocene flora from Ruzhintsi (NW Bulgaria). A revision of the species C. distans from the Satovcha paleoflora as Cornus aff. alba has also been made. A new finding of a leaf imprint from the Satovcha local paleoflora proves that the fossil material has the closest morphological features to the recent species C. alba.

The morphology and internal structure of dogwood (Cornus L.) endocarps in the taxonomy and phylogeny of the genus.

The genus Cornus is known for its complicated taxonomy and extreme polymorphism. Currently, dogwoods are classified into four morphological groups reflected in four phylogenetic clades: blue- or white-fruited dogwoods (BW), cornelian cherries (CC), big-bracted dogwoods (BB), and dwarf dogwoods (DW). The present study is a continuation of a series of papers that started with the examination of the endocarp morphological diversity among BW species. The endocarps of 22 Cornus species were studied according to their morphology, internal structure, and sculpture; the aim was to evaluate the taxonomic importance of the examined characters and check whether endocarp differentiation supports the published phylogenies, according to which the relationships within the genus are indicated as (BW(CC(DW-BB))). Among the quantitative characters, the endocarp’s length, thickness, and width, its length/width ratio, and the number of vascular bundles on its surface were considered taxonomically important. Regarding the qualitative characters, the taxonomic significance of the stone shape, the endocarp apex and base outline, the position of vascular bundles on the endocarp surface, and the presence of the apical cavity and distinct furrow on the endocarp side walls was proved. Additionally, the uniform qualitative characters having a 100% share of a given character state were identified. Cornelian cherries and dwarf dogwoods were characterised by the presence of four uniform characters. In the big-bracted group, two uniform characters were found. Blue- or white-fruited species were the most heterogeneous, with no uniform characters. Regarding the endocarp’s internal structure, the presence of secretory cavities in the endocarp wall and in the septa, the presence of crystals in the outer endocarp, the number of cell layers in the transition sclereid zone, and the primary and secondary sculptures were found to be taxonomically significant. Additionally, the comparative analyses of dogwood endocarps found the following parameters to be useful: the germination valve thickness, the ratio of endocarp wall thickness to endocarp diameter, and the septum’s width and structure. Due to the great differentiation of the examined characters, it was difficult to verify the research hypothesis unambiguously. The calculated similarity coefficients of the endocarps’ qualitative and quantitative characters revealed the highest morphological similarity of endocarps between DW and BB groups, supporting the phylogenetic relationships based on molecular evidence. The number of vascular bundles on the endocarp surface was the character that supported this similarity the most. The similarity coefficients calculated separately for qualitative characters showed the closest similarity between groups CC-DW. However, these results do not directly reflect any of the published phylogenies.

New alien taxa of the genus Cornus (Cornaceae) recorded in Lithuania and Latvia

Plants of the genus Cornus are valued for their ornamental qualities, are often grown in gardens, parks, or other public plantings, and form various shelterbelts. This increases the likelihood that these bird-dispersed plants will escape from their sites. This paper provides information on the first record of C. mas in Lithuania in 2021 at two sites. This species is currently considered a casual alien species, but may become locally naturalised in the future. This study confirmed that C. sericea is widespread in Lithuania, and the oldest herbarium specimen of the species was collected in 1997. Cornus sericea, like C. alba, is naturalised and potentially invasive in Lithuania. The alien subspecies of C. sanguinea (C. sanguinea subsp. australis) was found for the first time in Lithuania and Latvia in 2018. Available data show that this subspecies is naturalised in both countries, and its abundance in some areas in Lithuania indicates that it may become an invasive plant. The paper discusses dispersal vectors, occupied habitats, and the potential for spreading three alien Cornus taxa.

Evolutionary trade-offs in the chemical defense of floral and fruit tissues across genus Cornus.

Defense investment in plant reproductive structures is relatively understudied compared to the defense of vegetative organs. Here the evolution of chemical defenses in reproductive structures is examined in light of the optimal defense, apparency, and resource availability hypotheses within the genus Cornus using a phylogenetic comparative approach in relation to phenology and native habitat environmental data. Individuals representing 25 Cornus species were tracked for reproductive phenology over a full growing season at the Arnold Arboretum of Harvard University. Floral, fruit, and leaf tissue was sampled to quantify defensive chemistry as well as fruit nutritional traits relevant to bird dispersal. Native habitat environmental characteristics were estimated using locality data from digitized herbarium records coupled with global soil and climate data sets. The evolution of later flowering was correlated with increased floral tannins, and the evolution of later fruiting was correlated with increased total phenolics. Leaves were found to contain the highest tannin activity, while inflorescences contained the highest total flavonoids. Multiple aspects of fruit defensive chemistry were correlated with fruit nutritional traits. Floral and fruit defensive chemistry were evolutionarily correlated with aspects of native habitat temperature, precipitation, and soil characteristics. Results provide tentative support for the apparency hypothesis with respect to both flower and fruit phenology, while relative concentrations of secondary metabolites across organs provide mixed support for the optimal defense hypothesis. The evolution of reproductive defense with native habitat provides, at best, mixed support for the resource availability hypothesis.

Biometric characteristics of fruits and leaves of Cornus officinalis Siebold et Zucc. genotypes in the M.M. Gryshko National Botanical Garden of the NAS of Ukraine

In the context of global climate change, the current strategy of agroeconomics focuses on the introduction of unique plant species and the selection of new commercially important cultivars adapted to the dramatic weather changes. Cornus officinalis (Cornaceae) has Chinese origin, its reintroduction at the M.M. Gryshko National Botanical Garden, National Academy of Sciences of Ukraine started in 1993.
 The objectives of this research were: to investigate the biometric parameters of fruits and leaves of C. officinalis genotypes, C. officinalis × C. mas hybrid ‘Etude’ and genotype from the grafting C. officinalis on C. mas under cultivation in the M.M. Gryshko National Botanical Garden, National Academy of Sciences of Ukraine, and to determine the degree of adaptation of C. officinalis to the climatic conditions of Ukraine (in particular, Right-Bank Forest Steppe) for selection of promising genotypes for further breeding work.
 Material and methods. We used: a) 26-year-old maternal plant obtained from a two-year-old seedling in 1993 received from the nursery “Northwoods Wholesale Nursery” Mollala (Oregon, USA), where it was grown as an ornamental plant; b) seedlings of the maternal plant; c) cultivar Etude, which is an artificial hybrid from crossing C. officinalis × C. mas; and d) genotype obtained from grafting C. officinalis on C. mas. In our experiment, the maternal plant is indicated as G-01, while other plants – as G-02–G-08 genotypes. We determined the biometric parameters of the fruit (length, diameter, and weight), endocarp (length, diameter, and weight), pedicel (length and thickness), leaf blade (length, width, and the number of lateral veins) and petiole (length, width, and thickness). We examined the dynamics of fruit and endocarp formation during the season (genotypes G-01–G-03 and G-05) and compared the biometric characteristics of the fruit of genotypes G-01–G-05 from crops of two years, 2010 and 2018, which were most favorable in weather conditions. We have processed quantitative data in the PAST 2.10 software. The differences between the samples were estimated using the Tukey-Kramer test. The degree of variability was determined by the coefficient of variation. To assess the level of variability, we used the classification of Mamaev (1975).
 Results. We have found that the largest fruits in 2010 were observed in the genotype G-01 and the smallest – in the genotype G-03. The coefficient of variation of the linear parameters of the fruit and endocarp was in the range 5.7–10.1 %; the level of variability was very low or low. The variability of fruit weight and endocarp was high; the coefficient of variation was from 7.0 up to 28.3 %. The amplitude of the linear parameters of the leaf was wide (coefficient of variation was from 9.8 to 31.0 %). The cultivar Etude differed from other C. officinalis genotypes in size and weight of (M = 1800 mg, max = 2400 mg) and a much wider amplitude of variation in the length (17.9–22.6 vs. 14.3–18.2 mm) of the fruit. The largest leaves were in the genotypes G-08 and G-01, and the smallest – in the genotype G-02. The cultivar Etude did not differ so much by the mean leaf morphometric indices and number of veins, but it demonstrated one of the broadest leaf blades (51.5 mm).
 Conclusions. The data obtained in this study is important for the commercial use of C. officinalis and the cultivar Etude as food and medicinal plant, as well as for breeding in climatic conditions of Ukraine and analysis of hybridization features in the genus Cornus in general.

The Evolution of Functional Traits in Plants: Is the Giant Still Sleeping?

The Evolution of Functional Traits in Plants: Is the Giant Still Sleeping?

Cornus mas and Cornus Officinalis-Analogies and Differences of Two Medicinal Plants Traditionally Used.

Among 65 species belonging to the genus Cornus only two, Cornus mas L. and Cornus officinalis Sieb. et Zucc. (Cornaceae), have been traditionally used since ancient times. Cornus mas (cornelian cherry) is native to southern Europe and southwest Asia, whereas C. officinalis (Asiatic dogwood, cornel dogwood) is a deciduous tree distributed in eastern Asia, mainly in China, as well as Korea and Japan. Based on the different geographic distribution of the closely related species but clearly distinct taxa, the ethnopharmacological use of C. mas and C. officinalis seems to be independently originated. Many reports on the quality of C. mas fruits were performed due to their value as edible fruits, and few reports compared their physicochemical properties with other edible fruits. However, the detailed phytochemical profiles of C. mas and C. officinalis, in particular fruits, have never been compared. The aim of this review was highlighting the similarities and differences of phytochemicals found in fruits of C. mas and C. officinalis in relation to their biological effects as well as compare the therapeutic use of fruits from both traditional species. The fruits of C. mas and C. officinalis are characterized by the presence of secondary metabolites, in particular iridoids, anthocyanins, phenolic acids and flavonoids. However, much more not widely known iridoids, such as morroniside, as well as tannins were detected particularly in fruits of C. officinalis. The referred studies of biological activity of both species indicate their antidiabetic and hepatoprotective properties. Based on the available reports antihyperlipidemic and anticoagulant activity seems to be unique for extracts of C. mas fruits, whereas antiosteoporotic and immunomodulatory activities were assigned to preparations of C. officinalis fruits. In conclusion, the comparison of phytochemical composition of fruits from both species revealed a wide range of similarities as well as some constituents unique for cornelian cherry or Asiatic dogwood. Thus, these phytochemicals are considered the important factor determining the biological activity and justifying the use of C. mas and C. officinalis in the traditional European and Asiatic medicine.

Whole-genome duplication and molecular evolution in Cornus L. (Cornaceae) - Insights from transcriptome sequences.

The pattern and rate of genome evolution have profound consequences in organismal evolution. Whole-genome duplication (WGD), or polyploidy, has been recognized as an important evolutionary mechanism of plant diversification. However, in non-model plants the molecular signals of genome duplications have remained largely unexplored. High-throughput transcriptome data from next-generation sequencing have set the stage for novel investigations of genome evolution using new bioinformatic and methodological tools in a phylogenetic framework. Here we compare ten de novo-assembled transcriptomes representing the major lineages of the angiosperm genus Cornus (dogwood) and relevant outgroups using a customized pipeline for analyses. Using three distinct approaches, molecular dating of orthologous genes, analyses of the distribution of synonymous substitutions between paralogous genes, and examination of substitution rates through time, we detected a shared WGD event in the late Cretaceous across all taxa sampled. The inferred doubling event coincides temporally with the paleoclimatic changes associated with the initial divergence of the genus into three major lineages. Analyses also showed an acceleration of rates of molecular evolution after WGD. The highest rates of molecular evolution were observed in the transcriptome of the herbaceous lineage, C. canadensis, a species commonly found at higher latitudes, including the Arctic. Our study demonstrates the value of transcriptome data for understanding genome evolution in closely related species. The results suggest dramatic increase in sea surface temperature in the late Cretaceous may have contributed to the evolution and diversification of flowering plants.

Cretaceous origin of dogwoods: an anatomically preserved Cornus (Cornaceae) fruit from the Campanian of Vancouver Island.

BackgroundCornaceae consists of 58 species, all within the genus Cornus. The Cenozoic record of Cornus is extensive and well documented. Molecular divergence-time studies suggest that crown-group Cornus may have originated by the Late Cretaceous. However, there has been no formal report of Cornus from Cretaceous deposits. Here, we characterize a permineralized fossil fruit assignable to Cornus subg. Cornus from the Upper Cretaceous (Campanian) Shelter Point locality of Vancouver Island, British Columbia, Canada.MethodsSerial sections of the specimen were made using the cellulose acetate peel technique. Peels were mounted onto microscope slides and studied by light microscopy.ResultsThe fossil fruit consists of a tri-locular woody endocarp with dorsal germination valves. The locules are sub-triangular to ellipsoidal in transverse section and are separated by thin septa. Endocarp tissue consists of elongated and isodiametric sclereids and secretory cavities. Internal vascular tissue was not observed, but is interpreted to have been located along the outer periphery of the septa for some length, common in many cornalean taxa. There is one seed in each locule, one of which was found to have endosperm and a dicotyledonous embryo.DiscussionWoody endocarps with germination valves, without central vascular bundles, and with one seed per locule are characteristic of several families within the order Cornales. The interpreted vascular pattern and presence of secretory cavities indicates that the fossil fruit is assignable to Cornus subg. Cornus. Comparative analysis suggests that the fossil is most similar to Cornus piggae, a species described from the Paleocene of North Dakota. This fossil is the first evidence of crown-group Cornaceae from the Cretaceous and sheds light on both the plesiomorphic fruit characters and the timing of the initial diversification of the family and basal asterid lineage, Cornales.

Red osier dogwood (Cornus sericea L.) - a new invasive species in Slovenian flora

The Red osier dogwood (Cornus sericea L.) is a popular North American ornamental shrub, often planted also in Slovenia. Subspontaneous occurrence of the species in Slovenia is known for two decades, but only in recent years, we can recognize it as an invasive species. The Red osier dogwood is currently known from numerous localities in the wider city area of Ljubljana and also from two sites in the Gorenjska region. It occurs in wetland habitats, particularly in the vicinity of settlements, where the shrub is planted for ornamental purposes. To limit the invasion of the Red osier dogwood, timely measures should be taken. We also publish the updated determination key for the genus Cornus in Slovenia.

Three New Cultivars of Cornus kousa: Empire, Pam’s Mountain Bouquet, and Red Steeple

The genus Cornus contains 58 species of trees, shrubs, and herbs that are mostly distributed throughout the northern hemisphere (Xiang et al., 2006). Flowering dogwood (C. florida), kousa dogwood (C. kousa), and their interspecific hybrids are considered the most popular and economically significant members of the genus in the nursery and landscape industries. These deciduous trees are valued for their spring display of pink, red, or white bracts, brilliant-red fall foliage, and exfoliating bark. Retail and wholesale sales of dogwood in the United States account for over $30 million dollars annually with 73.1% of these sales coming from eight states [Maryland, Minnesota, New Jersey, North Carolina, Ohio, Oregon, Pennsylvania, and Tennessee (U.S. Dept. of Agriculture–National Agricultural Statistics Service, 2010)]. Sales in Tenneessee account for 21.9% of total sales of deciduous flowering trees, making it an important crop for the state’s economy. Additionally, six counties in Tennessee produce substantial amounts of 1-year-old liners that are sold to out-of-state nurseries for finishing and resale. In nursery production, a liner refers to a small tree that is transplanted and allowed to become a larger tree for sale by wholesale or retail outlets. These liners ultimately supply 80% of the country’s dogwoods (Simmons, 2002). Large-bracted dogwoods are widely grown throughout midtemperate regions of eastern North America, both in the wild and as coveted ornamental trees in urban and suburban landscapes. Across this range, flowering dogwoods have been severely affected by dogwood anthracnose [Discula destructiva (Redlin, 1991)] and powdery mildew [Erysiphe pulchra (Li et al., 2009)]. Because of the importance of dogwoods to the U.S. agricultural economy, an improvement program was initiated over 20 years ago at the University of Tennessee to develop disease-resistant cultivars of dogwoods. These efforts have resulted in the release of the first flowering dogwood cultivar (Appalachian Spring) with resistance to dogwood anthracnose (Windham et al., 1998) and three powdery mildew resistant cultivars: Jean’s Appalachian Snow, Karen’s Appalachian Blush, and Kay’s Appalachian Mist (Windham et al., 2003). Cornus kousa is more tolerant to anthracnose and powdery mildew than C. florida (Holmes and Hibben, 1989; Ranney et al., 1995). Hybrids between these two species are generally more vigorous than typical plants of either parent species and have field resistance or tolerance to dogwood anthracnose and powdery mildew (Ranney et al., 1995). There are over 100 named cultivars of C. kousa and many cultivars are the result of either selection of open-pollinated seedlings or spontaneous sports rather than systematic breeding (Cappiello and Shadow, 2005). The objective of this project was to evaluate 400 seedlings of C. kousa for disease resistance and horticultural traits such as color, degree of overlap, size of bracts, tree form, and bark and leaf characteristics. From these, three genotypes were selected for development and release.

Quantitative and qualitative differences in morphological traits of endocarps revealed between Cornus L. species

The genus Cornus encompasses a wide range of attractive wild taxa, often used as ornamental plants in landscaping. The aim of this investigation was to highlight the quantitative and qualitative diversity within endocarp morphological traits apparent among 15 Cornus species representing different geographical and phylogenetic groups. Seventeen morphological traits of Cornus endocarps were evaluated in 185 Cornus collections originating from the Northern Hemisphere. To explore structure in our dataset and reduce its complexity, several multivariate statistical analyses (i.e., PCA, MANOVA, ANOVA, and analysis of contingency tables) were employed. Two clearly distinct sample groups were observed after the PCA, reflecting a high level of taxonomic division of analyzed species, i.e., subgenera: Mesomora and Kraniopsis. The study highlights qualitative and/or quantitative characters that partitioned (1) groups of species or some individual species, (2) geographical groups, and (3) cultivated and wild collections. Results of trait validation are presented in identification keys. A partial congruence was detected between our results and a currently available species level phylogeny of the genus Cornus. The morphology of Cornus endocarps is of taxonomic importance and provides a key for species identification. The existence of only subtle morphological differences between some closely related taxa does not sufficiently explain their species status. The applicability of our results to the previously published morphological records is limited, mainly due to vague terminology. Considerably more work will need to be done to determine the effect of cultivation on qualitative reproductive traits of Cornus species.

Inflorescences: concepts, function, development and evolution

Inflorescences are complex structures with many functions. At anthesis they present the flowers in ways that allow for the transfer of pollen and optimization of the plant's reproductive success. During flower and fruit development they provide nutrients to the developing flowers and fruits. At fruit maturity they support the fruits prior to dispersal, and facilitate effective fruit and seed dispersal. From a structural point of view, inflorescences have played important roles in systematic and phylogenetic studies. As functional units they facilitate reproduction, and are largely shaped by natural selection. The papers in this Special Issue bridge the gap between structural and functional approaches to inflorescence evolution. They include a literature review of inflorescence function, an experimental study of inflorescences as essential contributors to the display of flowers, and two papers that present new methods and concepts for understanding inflorescence diversity and for dealing with terminological problems. The transient model of inflorescence development is evaluated in an ontogenetic study, and partially supported. Four papers present morphological and ontogenetic studies of inflorescence development in monophyletic groups, and two of these evaluate the usefulness of Hofmeister's Rule and inhibitory fields to predict inflorescence structure. In the final two papers, Bayesian and Monte-Carlo methods are used to elucidate inflorescence evolution in the Panicoid grasses, and a candidate gene approach is used in an attempt to understand the evolutionary genetics of inflorescence evolution in the genus Cornus (Cornaceae). Taken as a whole, the papers in this issue provide a glimpse of contemporary approaches to the study of the structure, development, and evolution of inflorescences, and suggest fruitful new directions for research.

Transfer of Cornus florida and C. kousa Simple Sequence Repeats to Selected Cornus (Cornaceae) Species

Cross-species transferability of simple sequence repeats (SSRs) is common and allows SSRs isolated from one species to be applied to closely related species, increasing the use of previously isolated SSRs. The genus Cornus consists of 58 species that are ecologically and economically important. SSRs have previously been isolated from C. florida and C. kousa. In this study, 36 SSRs were tested on taxa from 18 Cornus species and hybrids for cross-species transferability and genetic diversity was calculated for each locus using polymorphism information content (PIC). Cross-species transferability of SSR loci was higher in more closely related species and PIC values were high. Evidence was found for conserved primer sites as determined by the amplification of SSR loci in the taxa examined. Polymerase chain reaction products were cloned and sequenced for three SSR loci (CF48, CF59, and CF124) and all individuals sequenced contained the appropriate repeat. Phylogenetic relationships of 14 Cornus species were inferred using nucleotide sequences of SSR locus CF48. The most parsimonious tree resulting from this analysis was in concordance with phylogenies based on matK and internal transcribed spacer sequences. The SSR loci tested in this study will be useful in future breeding, population, and genetic studies within Cornus.

Molecular evolution of PISTILLATA-like genes in the dogwood genus Cornus (Cornaceae)

The MADS-box gene family encodes critical regulators determining floral organ development. Understanding evolutionary patterns and processes of MADS-box genes is an important step toward unraveling the molecular basis of floral morphological evolution. In this study, we investigated the evolution of PI-like genes of the MADS-box family in the dogwood genus Cornus (Cornaceae). Cornus is a eudicot lineage in the asterids clade, and is intriguing in evolving petaloid bract morphology in two major lineages within the genus. The gene genealogy reconstructed using genomic DNA and cDNA sequences suggests multiple PI-like gene duplication events in Cornus. An ancient duplication event resulted in two ancient paralogs, CorPI-A and CorPI-B, which have highly diverged intron regions. Duplication of CorPI-A further resulted in two paralogs in one subgroup of Cornus, the BW group that does not produce modified bracts. Most species analyzed were found to contain more than one copy of the PI-like gene with most copies derived recently within species. Estimation and comparison of d N/d S ratios revealed relaxed selection in the PI-like gene in Cornus in comparison with the gene in the closely related outgroups Alangium and Davidia, and in other flowering plants. Selection also differed among major gene copies, CorPI-A and CorPI-B, and among different morphological subgroups of Cornus. Variation in selection pressures may indicate functional changes in PI-like genes after gene duplication and among different lineages. Strong positive selection at three amino acid sites of CorPI was also detected from a region critical for dimerization activity. Total substitution rates of the CorPI gene also differ among lineages of Cornus, showing a trend similar to that found in d N/d S ratios. We also found that the CorPI-A copy contains informative phylogenetic information when compared across species of Cornus.

Lipid peroxidation, cyclooxygenase enzyme and tumor cell proliferation inhibitory compounds in Cornus kousa fruits

The genus Cornus is well known for its medicinal properties. Bioassay-guided isolation and characterization of C. kousa fruits afforded kaempferol 3-O-rhamnoside (1), myricetin 3-O-rhamnoside (2), kaempferol 3-O-glucoside (3), cornin (4) and stenophyllin (5) in addition to ursolic acid and beta-sitosterol. These compounds are isolated for the first time from C. kousa. Compounds 1-5 inhibited Fe(2+) catalyzed lipid peroxidation by 63%, 57%, 61%, 53%, and 51%, at 23, 22, 23, 129, and 108 microM, respectively. Similarly, they inhibited COX-1 and -2 enzymes activities by 24% and 47%, 40% and 37%, 20% and 37%, 52% and 63%, and 48% and 55% respectively, at 231, 215, 226, 258, and 217 microM, respectively. At 129 microM, compound 4 displayed growth inhibition of HCT-116 (colon), MCF-7 (breast), NCI-H460 (lung), SF-268 (central nervous system CNS), and AGS (stomach) human tumor cell lines by 31%, 29%, 40%, 9%, and 28%, respectively. Similarly, compound 5 inhibited the growth of colon, breast, lung, CNS, and stomach tumor cell lines by 0%, 27%, 35%, 16%, and 27%, respectively, at 108 microM.

(290) Analysis of Genetic Diversity in Selected Cornus Species Using SSR Markers

The genus Cornus consists of many species, of which C. florida, C. kousa, C. mas, and C. stolonifera are four main ornamental species in North America, Asia, and Europe. For example, over 200 cultivars of C. florida alone have been developed for the nursery industry. Microsatellite loci, or SSR, are useful markers for studying genetic diversity and for creating linkage maps of the various species. The objective of this study was to investigate the genetic diversity between these four Cornus species and eight hybrids. Evaulation of the diversity will be useful in assessing the selection pressure of breeders and/or genetic drift of these dogwood cultivars/lines. Fifteen SSR primer pairs were selected to examine 56 Cornus cultivars and/or lines of the four species and hybrids. The study included 28 C. florida cultivars and lines, 15 C. kousa cultivars and lines, four C. stolonifera cultivars, one cultivar of C. mass and eight hybrids between various Cornus species. An exceptionally high level of diversity was detected among the 56 entries in both the number and size range of SSR alleles. A total of 95 alleles with an average of 7.8 alleles per loci were detected among these 56 genotypes. These selected Cornus cultivars and/or lines could be clustered into four to six subgroups. Some Cornus species were integrated into other species groups, suggesting gene flow between species via the breeding or evolution. SSR markers can contribute to the exploitation of genetic diversity for existing Cornus germplasm. For further study, examination of more SSR loci could explain more completely the diversity among these Cornus cultivars and lines.