Rose Flowers-A Delicate Perfume or a Natural Healer?

Plants from the Rosacea family are rich in natural molecules with beneficial biological properties, and they are widely appreciated and used in the food industry, perfumery, and cosmetics. In this review, we are considering Rosa damascena Mill., Rosa alba L., Rosa centifolia L., and Rosa gallica L. as raw materials important for producing commercial products, analyzing and comparing the main biological activities of their essential oils, hydrolates, and extracts. A literature search was performed to find materials describing (i) botanical characteristics; (ii) the phytochemical profile; and (iii) biological properties of the essential oil sand extracts of these so called "old roses" that are cultivated in Bulgaria, Turkey, India, and the Middle East. The information used is from databases PubMed, Science Direct, and Google Scholar. Roses have beneficial healing properties due to their richness of beneficial components, the secondary metabolites as flavonoids (e.g., flavones, flavonols, anthocyanins), fragrant components (essential oils, e.g., monoterpenes, sesquiterpenes), and hydrolysable and condensed tannins. Rose essential oils and extracts with their therapeutic properties-as respiratory antiseptics, anti-inflammatories, mucolytics, expectorants, decongestants, and antioxidants-are able to act as symptomatic prophylactics and drugs, and in this way alleviate dramatic sufferings during severe diseases.

Molecular Evidences for the Interactions of Auxin, Gibberellin, and Cytokinin in Bent Peduncle Phenomenon in Rose (Rosa sp.).

In roses (Rosa sp.), peduncle morphology is an important ornamental feature. The common physiological abnormality known as the bent peduncle phenomenon (BPP) seriously decreases the quality of rose flowers and thus the commercial value. Because the molecular mechanisms underlying this condition are poorly understood, we analysed the transcriptional profiles and cellular structures of bent rose peduncles. Numerous differentially expressed genes involved in the auxin, cytokinin, and gibberellin signaling pathways were shown to be associated with bent peduncle. Paraffin sections showed that the cell number on the upper sides of bent peduncles was increased, while the cells on the lower sides were larger than those in normal peduncles. We also investigated the large, deformed sepals that usually accompany BPP and found increased expression level of some auxin-responsive genes and decreased expression level of genes that are involved in cytokinin and gibberellin synthesis in these sepals. Furthermore, removal of the deformed sepals partially relieved BPP. In summary, our findings suggest that auxin, cytokinin, and gibberellin all influence the development of BPP by regulating cell division and expansion. To effectively reduce BPP in roses, more efforts need to be devoted to the molecular regulation of gibberellins and cytokinins in addition to that of auxin.

A high-quality genome sequence of Rosa chinensis to elucidate ornamental traits.

Rose is the world's most important ornamental plant, with economic, cultural and symbolic value. Roses are cultivated worldwide and sold as garden roses, cut flowers and potted plants. Roses are outbred and can have various ploidy levels. Our objectives were to develop a high-quality reference genome sequence for the genus Rosa by sequencing a doubled haploid, combining long and short reads, and anchoring to a high-density genetic map, and to study the genome structure and genetic basis of major ornamental traits. We produced a doubled haploid rose line ('HapOB') from Rosa chinensis 'Old Blush' and generated a rose genome assembly anchored to seven pseudo-chromosomes (512 Mb with N50 of 3.4 Mb and 564 contigs). The length of 512 Mb represents 90.1-96.1% of the estimated haploid genome size of rose. Of the assembly, 95% is contained in only 196 contigs. The anchoring was validated using high-density diploid and tetraploid genetic maps. We delineated hallmark chromosomal features, including the pericentromeric regions, through annotation of transposable element families and positioned centromeric repeats using fluorescent in situ hybridization. The rose genome displays extensive synteny with the Fragaria vesca genome, and we delineated only two major rearrangements. Genetic diversity was analysed using resequencing data of seven diploid and one tetraploid Rosa species selected from various sections of the genus. Combining genetic and genomic approaches, we identified potential genetic regulators of key ornamental traits, including prickle density and the number of flower petals. A rose APETALA2/TOE homologue is proposed to be the major regulator of petal number in rose. This reference sequence is an important resource for studying polyploidization, meiosis and developmental processes, as we demonstrated for flower and prickle development. It will also accelerate breeding through the development of molecular markers linked to traits, the identification of the genes underlying them and the exploitation of synteny across Rosaceae.

Genomic and transcriptomic sequencing of Rosa hybrida provides microsatellite markers for breeding, flower trait improvement and taxonomy studies.

BACKGROUND: Rosa hybrida is a valuable ornamental, food and medicinal crop worldwide, but with relatively limited molecular marker resources, especially for flower-specific markers. In this study, we performed genomic and floral transcriptomic sequencing of modern rose. We obtained comprehensive nucleotide information, from which numerous potential simple sequence repeat (SSR) markers were identified but were found to have high rates of amplification failure and PCR product redundancy. RESULTS: We applied a filtering strategy for BLAST analysis with the assembled genomic sequence and identified 124,591 genomic and 2,292 EST markers with unique annealing sites. These markers had much greater reliability than those obtained before filtering. Additional BLAST analysis against the transcriptomic sequences uncovered 5225 genomic SSRs associated with 4100 transcripts, 2138 of which were associated with functional genes that were annotated against the non-redundant database. More than 90% of these newly developed molecular markers were polymorphic, based on PCR using a subset of SSRs to analyze tetraploid modern rose accessions, diploid Rosa species and one strawberry accession. The relationships among Rosa species determined by cluster analysis (based on these results) were in agreement with modern rose breeding history, whereas strawberry was isolated in a separate cluster, as expected. CONCLUSIONS: Our results provide valuable molecular-genetic tools for rose flower trait improvement, breeding and taxonomy. Importantly, we describe a reproducible organ-specific strategy for molecular marker development and selection in plants, which can be applied to other crops.

Rose Prickles and Asparagus Spines--Different Hook Structures as Attachment Devices in Climbing Plants.

Functional morphology and biomechanical properties of hook structures functioning as attachment devices in the leaning climbers Rosa arvensis, Rosa arvensis 'Splendens', Asparagus falcatus and Asparagus setaceus are analysed in order to investigate the variability in closely related species as well as convergent developments of hook structure and properties in distant systematic lineages (monocots and dicots). Prickles and spines were characterised by their size, orientation and the maximum force measured at failure in mechanical tests performed with traction forces applied at different angles. In Rosa arvensis and Rosa arvensis 'Splendens' three types of prickles differing largely in geometrical and mechanical properties are identified (prickles of the wild species and two types of prickles in the cultivar). In prickles of Rosa arvensis no particular orientation of the prickle tip is found whereas in the cultivar Rosa arvensis 'Splendens' prickles gradually gain a downward-orientation due to differential growth in the first weeks of their development. Differences in mechanical properties and modes of failure are correlated to geometrical parameters. In Asparagus falcatus and Asparagus setaceus spines are composed of leaf tissue, stem tissue and tissue of the axillary bud. Between species spines differ in size, orientation, distribution along the stem, tissue contributions and mechanical properties. The prickles of Rosa arvensis and its cultivar and the spines of the studied Asparagus species have several traits in common: (1) a gradual change of cell size and cell wall thickness, with larger cells in the centre and smaller thick-walled cells at the periphery of the hooks, (2) occurrence of a diversity of shape and geometry within one individual, (3) failure of single hooks when submitted to moderate mechanical stresses (Fmax/basal area < 35 N/mm²) and (4) failure of the hooks without severe stem damage (at least in the tested wild species).

The non-native plant Rosa multiflora expresses shade avoidance traits under low light availability.

UNLABELLED: • PREMISE OF THE STUDY: Shade tolerance is a key trait promoting invasive plant performance in forest interiors. Rosa multiflora is a problematic invasive shrub in the northeastern United States, occurring in edge habitats and encroaching into forests. Our objective was to evaluate the shade tolerance of R. multiflora to assess how ecophysiological traits may facilitate its spread into forest interiors.• METHODS: In the field, we documented shrub and seed bank density, fecundity, phenology, and seasonal photosynthetic rates of R. multiflora in contrasting light environments. In the greenhouse, we exposed seedlings to simulated canopy treatments by altering spectral quantity and quality, mimicking habitats ranging from open fields to forest interiors.• KEY RESULTS: In the field, shrub density and fecundity of R. multiflora sharply increased with light availability. However, no differences were observed between forest edge and interior seed banks. Rosa multiflora initiated leaf growth earlier and retained leaves longer than canopy vegetation and tended to have higher photosynthetic rates in spring and fall. In the greenhouse, plants displayed shade-avoidance traits, decreasing relative growth rate and reducing branching, while increasing elongation and showing no change in light response curve parameters.• CONCLUSIONS: In deciduous forest understories, R. multiflora appears to make use of a lengthened growing season in spring and fall, and therefore, substantial growth and spread through intact forests appears dependent on canopy gaps. Management should focus on reducing edge populations to reduce spread into the interior and on monitoring newly created canopy gaps.

Pleistocene glaciations, demographic expansion and subsequent isolation promoted morphological heterogeneity: A phylogeographic study of the alpine Rosa sericea complex (Rosaceae).

While most temperate plants probably underwent glacial constriction to refugia and interglacial expansion, another type of interglacial refugia might have existed to maintain alpine plants during warm periods. To test this hypothesis, we applied phylogeographic methods to 763 individuals (62 populations) which belong to 7 taxonomically difficult species of the Rosa sericea complex distributed in alpine regions of the temperate and subtropical zones in eastern Asia. We used three chloroplast (cp) DNA fragments (trnL-trnF, ndhF-rpl32 and ndhJ-trnF) approximately 3,100 bp and nuclear microsatellite (nSSR) on eight sites to determine whether cold tolerant plants experienced expansion during the Pleistocene. The neutral test and mismatch distribution analysis (MDA) indicated that whole populations and major lineages of the Qinghai-Tibet Plateau (QTP) underwent expansion during the middle to late Pleistocene. Environmental niche modeling (ENM) indicates more suitable habitats during the Last Glacial Maximum (LGM) than at present. We concluded that the demographic history of R. sericea, which diverged in the middle Pleistocene, was mostly affected by climatic oscillations instead of by geographical barriers. The low genetic divergence, as well as the weak phylogenetic structure in the R. sericea complex both support treating this complex as a single taxon.

Genetic variation, heritability and genotype by environment interaction of morphological traits in a tetraploid rose population.

BACKGROUND: Global trade has ensured that the ornamental horticulture continues to grow worldwide, with rose hybrids being the most economically important genus (Rosa x hybrida). Due to changes in global trade and an increase in energy costs the ornamental industry has seen a shift in the production and sale of flowers from the US and Europe alone to production in Africa and Latin America. As Kenya is a major exporter of roses to Europe we studied the genetic variation and heritability of specific morphological traits in a tetraploid population grown in the Netherlands and in Kenya. The aim was to estimate genotype by environment interaction (G × E) and to investigate the implications of (G × E) for rose breeding. RESULTS: A tetraploid rose population (K5) from a cross between two tetraploid parents was field tested over two seasons in the Netherlands (summer and winter) and two locations in Kenya (Nairobi and Njoro). Ten traits were compared per genotype across the four environments. There were differences in trait association across the four environments showing that the traits were partially influenced by the environment. The traits that had a low ratio of σ(2) ge/σ(2) g also showed a high value for heritability. For the traits number of petals, prickles on petioles, prickles on stems the interaction is minimal. For the traits chlorophyll content, stem width and side shoots we observed a much higher interaction ratio of 0.83, 1.43 and 3.13 respectively. The trait number of petals had the highest heritability of 0.96 and the lowest σ(2) ge/σ(2) g ratio (0.08). The trait number of side shoots (SS) with the lowest heritability (0.40) also had the highest σ(2) ge/σ(2) g ratio of 3.13. CONCLUSION: Attained by this experiment showed that we have different magnitudes of non-crossover G × E interactions. For the traits number of petals, prickles on stems and prickles on petioles with a low interaction and high heritability, selection can be done at any of the environments. Thus, these traits can be confirmed at the breeding site. For the traits stem width, side shoots and chlorophyll content that had a higher interaction selection for or against these traits should be done at the production location or at least be verified there.

Spectral effects of supplementary lighting on the secondary metabolites in roses, chrysanthemums, and campanulas.

To investigate the effect of the light spectrum on photosynthesis, growth, and secondary metabolites Rosa hybrida 'Scarlet', Chrysanthemum morifolium 'Coral Charm', and Campanula portenschlagiana 'BluOne' were grown at 24/18°C day/night temperature under purpose-built LED arrays yielding approximately 200 µmol m(-2)s(-1) at plant height for 16 h per day. The four light treatments were (1) 40% Blue/60% Red, (2) 20% Blue/80% Red, (3) 100% Red, and (4) 100% White (Control). The plant height was smallest in 40% Blue/60% Red in roses and chrysanthemums, while the biomass was smallest in the white control in roses and in 100% Red in chrysanthemums. The total biomass was unaffected by the spectrum in campanulas, while the leaf area was smallest in the 40% Blue/60% Red treatment. In 100% Red curled leaves and other morphological abnormalities were observed. Increasing the blue to red ratio increased the stomatal conductance though net photosynthesis was unaffected, indicating excess stomatal conductance in some treatments. With higher blue light ratio all phenolic acids and flavonoids increased. In view of the roles of these secondary metabolites as antioxidants, anti-pathogens, and light protectants, we hypothesize that blue light may predispose plants to better cope with stress.

Kernel methods for phenotyping complex plant architecture.

The Quantitative Trait Loci (QTL) mapping of plant architecture is a critical step for understanding the genetic determinism of plant architecture. Previous studies adopted simple measurements, such as plant-height, stem-diameter and branching-intensity for QTL mapping of plant architecture. Many of these quantitative traits were generally correlated to each other, which give rise to statistical problem in the detection of QTL. We aim to test the applicability of kernel methods to phenotyping inflorescence architecture and its QTL mapping. We first test Kernel Principal Component Analysis (KPCA) and Support Vector Machines (SVM) over an artificial dataset of simulated inflorescences with different types of flower distribution, which is coded as a sequence of flower-number per node along a shoot. The ability of discriminating the different inflorescence types by SVM and KPCA is illustrated. We then apply the KPCA representation to the real dataset of rose inflorescence shoots (n=1460) obtained from a 98 F1 hybrid mapping population. We find kernel principal components with high heritability (>0.7), and the QTL analysis identifies a new QTL, which was not detected by a trait-by-trait analysis of simple architectural measurements. The main tools developed in this paper could be use to tackle the general problem of QTL mapping of complex (sequences, 3D structure, graphs) phenotypic traits.

Foliar abscisic acid content underlies genotypic variation in stomatal responsiveness after growth at high relative air humidity.

BACKGROUND AND AIMS: Stomata formed at high relative air humidity (RH) respond less to abscisic acid (ABA), an effect that varies widely between cultivars. This study tested the hypotheses that this genotypic variation in stomatal responsiveness originates from differential impairment in intermediates of the ABA signalling pathway during closure and differences in leaf ABA concentration during growth. METHODS: Stomatal anatomical features and stomatal responsiveness to desiccation, feeding with ABA, three transduction elements of its signalling pathway (H2O2, NO, Ca(2+)) and elicitors of these elements were determined in four rose cultivars grown at moderate (60 %) and high (90 %) RH. Leaf ABA concentration was assessed throughout the photoperiod and following mild desiccation (10 % leaf weight loss). KEY RESULTS: Stomatal responsiveness to desiccation and ABA feeding was little affected by high RH in two cultivars, whereas it was considerably attenuated in two other cultivars (thus termed sensitive). Leaf ABA concentration was lower in plants grown at high RH, an effect that was more pronounced in the sensitive cultivars. Mild desiccation triggered an increase in leaf ABA concentration and equalized differences between leaves grown at moderate and high RH. High RH impaired stomatal responses to all transduction elements, but cultivar differences were not observed. CONCLUSIONS: High RH resulted in decreased leaf ABA concentration during growth as a result of lack of water deficit, since desiccation induced ABA accumulation. Sensitive cultivars underwent a larger decrease in leaf ABA concentration rather than having a higher ABA concentration threshold for inducing stomatal functioning. However, cultivar differences in stomatal closure following ABA feeding were not apparent in response to H2O2 and downstream elements, indicating that signalling events prior to H2O2 generation are involved in the observed genotypic variation.

Smaller stomata require less severe leaf drying to close: a case study in Rosa hydrida.

Stomata formed at high relative air humidity (RH) close less as leaf dries; an effect that varies depending on the genotype. We here quantified the contribution of each stomatal response characteristic to the higher water loss of high RH-grown plants, and assessed the relationship between response characteristics and intraspecific variation in stomatal size. Stomatal size (length multiplied by width), density and responsiveness to desiccation, as well as pore dimensions were analyzed in ten rose cultivars grown at moderate (60%) or high (85%) RH. Leaf morphological components and transpiration at growth conditions were also assessed. High growth RH resulted in thinner (11%) leaves with larger area. A strong positive genetic correlation of daytime and nighttime transpiration at either RH was observed. Stomatal size determined pore area (r=0.7) and varied by a factor of two, as a result of proportional changes in length and width. Size and density of stomata were not related. Following desiccation, high RH resulted in a significantly lower (6-19%) decline of transpiration in three cultivars, whereas the relative water content (RWC) of high RH-expanded leaflets was lower (29-297%) in seven cultivars. The lower RWC of these leaflets was caused by (a) higher (33-72%) stable transpiration and/or (b) lower (12-143%) RWC at which this stable transpiration occurred, depending on the cultivar. Stomatal size was significantly correlated with both characteristics (r=0.5 and -0.7, respectively). These results indicate that stomatal size explains much of the intraspecific variation in the regulation of transpiration upon water deprivation on rose.

A comprehensive analysis of the physiological and anatomical components involved in higher water loss rates after leaf development at high humidity.

To better understand the poor regulation of water loss after leaf development at high relative air humidity (RH), the relative importance of the physiological and anatomical components was analyzed focusing on cultivars with a contrasting sensitivity to elevated RH. The stomatal responsiveness to three closing stimuli (desiccation, abscisic acid feeding, light/dark transition), as well as several stomatal features (density, index, size and pore dimensions) and the cuticular transpiration rate (CTR) were determined in four rose cultivars, grown under moderate (60%) and high (95%) RH. Moreover, the effects of changes in stomatal density and pore dimensions on the stomatal conductance (gs) were quantified using a modified version of the Brown and Escombe equation. Higher water loss, as a result of plant growth at high RH, was primarily caused by an increase in residual gs, and to a lesser extent due to higher CTR. It was estimated that in leaflets subjected to desiccation the enhanced gs in high RH- as compared to moderate RH-grown plants was mostly due to poor stomatal functionality and to a lesser extent the combined result of higher stomatal density and longer pore length. It is concluded that the reduced degree and, specially, the reduced rate of stomatal closure are the primary causes of the large genotypic variation in the control of water loss in high RH-grown plants. Furthermore, it was found that although changes in stomatal length have no influence on stomatal functionality, changed anatomical features per se represent a significant and direct contribution to the increased water loss.

[Effects of plant growth regulators on cutting propagation of Rosa laevigata].

OBJECTIVE: To explore the optimal plant growth regulator and its suitable concentration for the cutting propagation of Rosa laevigata. METHODS: The cuttings were dealt with 6 kinds of plant growth regulators (IAA,IBA, NAA, PP333, 2, 4-D and ABT) at different concentrations (100, 200 and 500 mg/L) for 50 seconds. After 30 days growth, by analysis of variance and multiple comparisons,the most suitable cutting propagation method for Rosa laevigata was found. RESULTS: Under the same condition, different concentration of different kinds of plant growth regulators had different effects on cutting propagation of Rosa laevigata. Generally speaking,cuttings soaked with 200 mg/L PP333 for 50 seconds was the best,with the high multiple effectiveness index and average root number (12.42); Cuttings soaked with 200 mg/L IBA for 50 seconds also had significant effects, with the second high multiple effectiveness index and the highest survival rate (96.67%). CONCLUSION: 200 mg/L PP333 can promote cutting propagation of Rosa laevigata best.

RhNAC2 and RhEXPA4 are involved in the regulation of dehydration tolerance during the expansion of rose petals.

Dehydration inhibits petal expansion resulting in abnormal flower opening and results in quality loss during the marketing of cut flowers. We constructed a suppression subtractive hybridization library from rose (Rosa hybrida) flowers containing 3,513 unique expressed sequence tags and analyzed their expression profiles during cycles of dehydration. We found that 54 genes were up-regulated by the first dehydration, restored or even down-regulated by rehydration, and once again up-regulated by the second dehydration. Among them, we identified a putative NAC family transcription factor (RhNAC2). With transactivation activity of its carboxyl-terminal domain in yeast (Saccharomyces cerevisiae) cell and Arabidopsis (Arabidopsis thaliana) protoplast, RhNAC2 belongs to the NAC transcription factor clade related to plant development in Arabidopsis. A putative expansin gene named RhEXPA4 was also dramatically up-regulated by dehydration. Silencing RhNAC2 or RhEXPA4 in rose petals by virus-induced gene silencing significantly decreased the recovery of intact petals and petal discs during rehydration. Overexpression of RhNAC2 or RhEXPA4 in Arabidopsis conferred strong drought tolerance in the transgenic plants. RhEXPA4 expression was repressed in RhNAC2-silenced rose petals, and the amino-terminal binding domain of RhNAC2 bound to the RhEXPA4 promoter. Twenty cell wall-related genes, including seven expansin family members, were up-regulated in Arabidopsis plants overexpressing RhNAC2. These data indicate that RhNAC2 and RhEXPA4 are involved in the regulation of dehydration tolerance during the expansion of rose petals and that RhEXPA4 expression may be regulated by RhNAC2.

Identification of diacylglycerol acyltransferase inhibitors from Rosa centifolia petals.

Diacylglycerol acyltransferase (DGAT) catalyzes the final step of triacylglycerol (TAG) synthesis, and is considered as a potential target to control hypertriglyceridemia or other metabolic disorders. In this study, we found that the extract of rose petals suppressed TAG synthesis in cultured cells, and that the extract showed DGAT inhibitory action in a dose-dependent manner. Fractionation of the rose extract revealed that the DGAT inhibitory substances in the extract were ellagitannins; among them rugosin B, and D, and eusupinin A inhibited DGAT activity by 96, 82, and 84% respectively, at 10 µM. These substances did not inhibit the activities of other hepatic microsomal enzymes, glucose-6-phosphatase and HMG-CoA reductase, or pancreatic lipase, suggesting that ellagitannins inhibit DGAT preferentially. In an oral fat load test using mice, postprandial plasma TAG increase was suppressed by rose extract; TAG levels 2 h after the fat load were significantly lower in mice administered a fat emulsion containing rose extract than in control mice (446.3 ± 33.1 vs 345.3 ± 25.0 mg/dL, control vs rose extract group; P < 0.05). These results suggest that rose ellagitannins or rose extract could be beneficial in controlling lipid metabolism and used to improve metabolic disorders.

Quantitative trait loci for flowering time and inflorescence architecture in rose.

The pattern of development of the inflorescence is an important characteristic in ornamental plants, where the economic value is in the flower. The genetic determinism of inflorescence architecture is poorly understood, especially in woody perennial plants with long life cycles. Our objective was to study the genetic determinism of this characteristic in rose. The genetic architectures of 10 traits associated with the developmental timing and architecture of the inflorescence, and with flower production were investigated in a F(1) diploid garden rose population, based on intensive measurements of phenological and morphological traits in a field. There were substantial genetic variations in inflorescence development traits, with broad-sense heritabilities ranging from 0.82 to 0.93. Genotypic correlations were significant for most (87%) pairs of traits, suggesting either pleiotropy or tight linkage among loci. However, non-significant and low correlations between some pairs of traits revealed two independent developmental pathways controlling inflorescence architecture: (1) the production of inflorescence nodes increased the number of branches and the production of flowers; (2) internode elongation connected with frequent branching increased the number of branches and the production of flowers. QTL mapping identified six common QTL regions (cQTL) for inflorescence developmental traits. A QTL for flowering time and many inflorescence traits were mapped to the same cQTL. Several candidate genes that are known to control inflorescence developmental traits and gibberellin signaling in Arabidopsis thaliana were mapped in rose. Rose orthologues of FLOWERING LOCUS T (RoFT), TERMINAL FLOWER 1 (RoKSN), SPINDLY (RoSPINDLY), DELLA (RoDELLA), and SLEEPY (RoSLEEPY) co-localized with cQTL for relevant traits. This is the first report on the genetic basis of complex inflorescence developmental traits in rose.

[Interspecific hybridization in wild roses (Rosa L. sect. Caninae DC.)].

Variability of morphological characters and Inter Simple Sequence Repeat (ISSR) markers is studied in a mixed multispecies sympatric growth of wild roses in Lugansk province of Ukraine. Several methods of data analysis are used, such as Principal Coordinates Analysis, cluster analysis (UPGMA), and Bayesian analyses of population structure with the Structure 2.2 and NewHybrids programs. The results indicate that there are four species growing at the site, viz. R. canina, R. villosa, R. dimorpha, and R. podolica, as well as various hybrids between them. The hybrid nature of the specimens is confirmed by molecular data, however they are not intermediate between the parental species as to their morphology. The hybrids either coincide morphologically with one of the parents, or demonstrate novel combinations of diagnostic characters.

Tinkering with the C-function: a molecular frame for the selection of double flowers in cultivated roses.

BACKGROUND: Roses have been cultivated for centuries and a number of varieties have been selected based on flower traits such as petal form, color, and number. Wild-type roses have five petals (simple flowers), whereas high numbers of petals (double flowers) are typical attributes of most of the cultivated roses. Here, we investigated the molecular mechanisms that could have been selected to control petal number in roses. METHODOLOGY/PRINCIPAL FINDINGS: We have analyzed the expression of several candidate genes known to be involved in floral organ identity determination in roses from similar genetic backgrounds but exhibiting contrasting petal numbers per flower. We show that the rose ortholog of AGAMOUS (RhAG) is differentially expressed in double flowers as compared to simple flowers. In situ hybridization experiments confirm the differential expression of RhAG and demonstrate that in the double-flower roses, the expression domain of RhAG is restricted toward the center of the flower. Conversely, in simple-flower roses, RhAG expression domain is wider. We further show that the border of RhAG expression domain is labile, which allows the selection of rose flowers with increased petal number. Double-flower roses were selected independently in the two major regions for domestication, China and the peri-Mediterranean areas. Comparison of RhAG expression in the wild-type ancestors of cultivated roses and their descendants both in the European and Chinese lineages corroborates the correlation between the degree of restriction of RhAG expression domain and the number of petals. Our data suggests that a restriction of RhAG expression domain is the basis for selection of double flowers in both the Chinese and peri-Mediterranean centers of domestication. CONCLUSIONS/SIGNIFICANCE: We demonstrate that a shift in RhAG expression domain boundary occurred in rose hybrids, causing double-flower phenotype. This molecular event was selected independently during rose domestication in Europe/Middle East and in China.

Antioxidative activities of white rose flower extract and pharmaceutical advantages of its hexane fraction via free radical scavenging effects.

In this study, we determined the antioxidant activities of two different solvent fractions(butanol and hexane) obtained from white Rosa rugosa flowers by employing various assays such as 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, and nitric oxide (NO) scavenging and inhibition activity in S-nitroso-N-acetylpenicillamine (SNAP) in the RAW264.7 model. In addition, more advanced antioxidant assays were conducted, including lipid peroxidation, hydroxyl radical-mediated oxidation, DNA fragmentation, apoptosis, and cell growth. The results revealed that the hexane fraction, which contained a significant amount of polyphenols and volatile components, had excellent antioxidant potency and could scavenge free radicals of DPPH and ABTS. Interestingly, the hexane fraction inhibited lipid peroxidation to almost the same degree as a chemical antioxidant. In the NO assay, the hexane fraction effectively scavenged free radicals at all dose ranges and is expected to inhibit NO production in mammalian cells. The hexane fraction effectively prevented oxidative damage, which was induced by Cu2+/H2O2, to target proteins at lower concentrations (>1 microg x mL(-1)). The DNA fragmentation and the cell-level assays suggest that the hexane fraction may play a crucial role in inhibiting peroxynitrite and H2O2 attack. Based on the findings described in this study, the hexane fraction holds promise for use as a novel pharmaceutical antioxidant.