Centaurea rupestris L.: Cytogenetics, Essential Oil Chemistry and Biological Activity

Centaurea species are used in eastern Mediterranean ethnopharmacology due to variety of bioactive compounds they comprise. Aim of this work was to characterize the Centaurea rupestris L. hydrodistilled essential oil chemical composition and test its biological activity: antimicrobial effect, antioxidant potential and inhibition of cholinesterases. Plant material authentication was by chromosome number counting and genome size assessment with the flow cytometry. Hydrodistilled essential oils were characterized using gas chromatography/mass spectrometry technique GC-MS and GC-FID. The antimicrobial effect was tested using disk diffusion and microdilution methods, antioxidant potential was tested with DPPH and FRAP methods and cholinesterases inhibition was tested with Ellman method. Genome size for C. rupestris species: sample A presented 2C=3.60 (0.10) pg and sample B 2C=3.62 (0.08) pg. The chromosome number was 2n=20 for both samples. The main essential oil constituents in isolated sample A oil, detected with GC-MS and GC-FID were: germacrene D (24.3 %), heptacosane (14.4 %), phytol (6.7 %), β-caryophyllene (5.0 %) and pentacosane (4.5 %). Sample B essential oil had the main constituents: hexadecanoic acid (18.7 %), heptacosane (13.8 %), α-linolenic acid (11.8 %), nonacosane (7.8 %) and germacrene D (5.4 %). Both samples of oil showed broad spectrum antimicrobial effect with good activity against emerging Gram-positive and Gram-negative opportunistic pathogens and pathogenic fungi which indicates the pharmaceutical potential of the C. rupestris essential oil. This work is licensed under a Creative Commons Attribution 4.0 International License

Genome size and chromosome number of Micromeria acropolitana (Lamiaceae), a steno-endemic from Greece

Abstract. The chromosome number 2n = 30, and nuclear DNA amount 2C = 0.79 pg, are determined for the first time for Micromeria acropolitana, a rare and endangered species from the Acropolis in Athens, Greece. The plant was considered extinct but rediscovered in 2006, a hundred years later. Its current status in the original habitat is assessed, and proposals for ensuring its survival presented

Flow cytometry as tool in plant sciences, with emphasis on genome size and ploidy level assessment

Flow cytometry has become the method of choice to measure the DNA content (genome size) in plants. Ease of sample preparation, fast acquisition, and accurate measurements have made the method popular in the domains of plant cell biology, systematics, evolution, genetics and biotechnology. Although the cell wall is a problem when isolating plant cells, cytometry remains a powerful tool in plant sciences. Based on our 30-years’ experience in this field, this review will focus at first on genome size measurement using simply isolated nuclei: the good practice for acquisition, nuclei isolation, appropriate buffers, kind of tissues to use. The second part will briefly review what kind of measurements it is possible to make in plant cytometry, and for what purpose: base composition, ploidy level, cell cycle, endoreplication, seed screening, and nuclei/chromosomes sorting. We will address troubleshooting. The commonly-used mathematic tools will be discussed

Evolutionary implications of heterochromatin and rDNA in chromosome number and genome size changes during dysploidy: a case study in Reichardia genus

In this study we showed that constitutive heterochromatin, GC-rich DNA and rDNA are implicated in chromosomal rearrangements during the basic chromosome number changing (dysploidy) in Reichardia genus. This small Mediterranean genus comprises 8-10 species and presents three basic chromosome numbers (x = 9, 8 and 7). To assess genome evolution and differentiation processes, studies were conducted in a dysploid series of six species: R. dichotoma, R. macrophylla and R. albanica (2n = 18), R. tingitana and R. gaditana (2n = 16), and R. picroides (2n = 14). The molecular phylogeny reconstruction comprised three additional species (R. crystallina and R. ligulata, 2n = 16 and R. intermedia, 2n = 14). Our results indicate that the way of dysploidy is descending. During this process, a positive correlation was observed between chromosome number and genome size, rDNA loci number and pollen size, although only the correlation between chromosome number and genome size is still recovered significant once considering the phylogenetic effect. Fluorescent in situ hybridisation also evidenced changes in number, position and organisation of two rDNA families (35S and 5S), including the reduction of loci number and, consequently, reduction in the number of secondary constrictions and nuclear organising regions from three to one per diploid genome. The potential mechanisms of chromosomal and genome evolution, strongly implicating heterochromatin, are proposed and discussed, with particular consideration for Reichardia genus

Nuclear and chloroplast DNAs reveal diverse origins and mis-identifications of Juniperus cultivars from Windsor Gardens, UK, Part 3 of 3

Ploidy was determined for 15 plants labeled as Juniperus squamata at the Windsor Gardens, UK and revealed 12 were tetraploids (2n=4x=44) and 3 were diploids (2n=2x=22). nrDNA (ITS) and cp DNA sequencing the tetraploids found: 4 J. squamata (4x); 4 J. tibetica (4x) x J. squamata (4x); 2 J. sabina var. balkanensis (4x) x J. squamata (4x); and one J. chinensis var. sargentii (4x) x J. squamata (4x). Sequencing the 3 diploids revealed: 2 J. pingii (2x) x J. pingii (2x); and 1 J. pingii (2x)? x J. komarovii(2x)? Ploidy analyses of 18 additional cultivars, putatively from Juniperus davurica, J. recurva, J. rushforthiana, J. sabina, and J. virginiana revealed 6 diploids, 5 triploids and 7 tetraploids. Cultivar \u27Musgrave\u27 (4x), by DNA, was identical to J. xpfitzeriana \u27Wilhelm Pfitzer\u27 (4x). The DNA of the 5 triploids were all nearly identical to J. xpfitzeriana \u27Wilhelm Pfitzer\u27 (4x). \u27Tamariscifolia\u27 and \u27Variegata\u27 both had J. sabina var. sabina as their maternal parent, but the first had J. sabina var. balkanensis as the male parent and the second had J. sabina var. sabina as the male parent. Thus, \u27Tamariscifolia\u27 is the first discovery of a J. sabina var. balkanensis x J. s. var. sabina hybrid in cultivation. None of the 3 \u27davurica\u27 cultivars proved to be J. davurica, but rather J. chinensis var. procumbens x J. chinensis var. sargentii. Cultivars J. indica and recurva \u27densa\u27 were shown to be J. indica var. caespitosa. recurva \u27 Embley Park\u27 appears to be J. coxii x J. squamata var. wilsonii. J. wallichiana (=J. indica) 15460 was found to be J. rushforthiana, whereas J. wallichiana (15487) was discovered to be J. indica x J. rushforthiana. Cultivar virginiana \u27cannaertii\u27 was shown to be J. virginiana. Botanic gardens provide a great opportunity for species to hybridize with other species that are not in contact in nature. The species care and suitable habitat provided in a garden setting, as well as vegetative propagation methods have allowed the preservation of those rare hybrids). Identification of juniper hybrids and variants is quite imprecise. DNA barcoding of cultivated plants in botanic gardens would greatly facilitate the recognition, study and utilization of rare hybrids and somatic mutations

Discovery of Juniperus sabina var. balkanensis R. P. Adams and A. N. Tashev in Macedonia, Bosnia-Herzegovina, Croatia and Central and Southern Italy and relictual polymorphisms found in nrDNA

Additional analyses of trnS-trnG and nrDNA from specimens from Bosnia-Herzegovina, southern and central, Italy, Croatia and Macedonia revealed the presence of J. sabina var. balkanensis in these areas west of the previously known populations in Greece, Bulgaria and western Turkey. Careful chromatogram analysis of eight (8) polymorphic sites in nrDNA revealed that nearly all of the populations of both var. balkanensis and var. sabina contained from 2 to 8 polymorphic sites. For these 8 heterozygous sites, two exclusive patterns were found in J. sabina. One type (GGACCCAG) was found in 16/62 plants and type 2 (ACGACAGT) was found in 4/62 plants. The majority of the plants examined (42/62) were heterozygous for 1 to 8 sites. These two nrDNA types appear to have arisen via hybridization with a J. thurifera ancestor. The two types appear in both v. sabina and v. balkanensis populations. Extant putative hybrids appear to have formed by crosses between present day type 1 and type 2 nrDNA

Polyploidy in the Conifer Genus Juniperus: An Unexpectedly High Rate

Recent research suggests that the frequency of polyploidy may have been underestimated in gymnosperms. One notable example is in the conifer genus Juniperus, where there are already a few reports of polyploids although data are still missing for most species. In this study, we evaluated the extent of polyploidy in Juniperus by conducting the first comprehensive screen across nearly all of the genus. Genome size data from fresh material, together with chromosome counts, were used to demonstrate that genome sizes estimated from dried material could be used as reliable proxies to uncover the extent of ploidy diversity across the genus. Our analysis revealed that 16 Juniperus taxa were polyploid, with tetraploids and one hexaploid being reported. Furthermore, by analyzing the genome size and chromosome data within a phylogenetic framework we provide the first evidence of possible lineage-specific polyploidizations within the genus. Genome downsizing following polyploidization is moderate, suggesting limited genome restructuring. This study highlights the importance of polyploidy in Juniperus, making it the first conifer genus and only the second genus in gymnosperms where polyploidy is frequent. In this sense, Juniperus represents an interesting model for investigating the genomic and ecological consequences of polyploidy in conifers

Recent updates and developments to plant genome size databases

Two plant genome size databases have been recently updated and/or extended: the Plant DNA C-values database (http://data.kew.org/cvalues), and GSAD, the Genome Size in Asteraceae database (http://www.asteraceaegenomesize.com). While the first provides information on nuclear DNA contents across land plants and some algal groups, the second is focused on one of the largest and most economically important angiosperm families, Asteraceae. Genome size data have numerous applications: they can be used in comparative studies on genome evolution, or as a tool to appraise the cost of whole-genome sequencing programs. The growing interest in genome size and increasing rate of data accumulation has necessitated the continued update of these databases. Currently, the Plant DNA C-values database (Release 6.0, Dec. 2012) contains data for 8510 species, while GSAD has 1219 species (Release 2.0, June 2013), representing increases of 17 and 51%, respectively, in the number of species with genome size data, compared with previous releases. Here we provide overviews of the most recent releases of each database, and outline new features of GSAD. The latter include (i) a tool to visually compare genome size data between species, (ii) the option to export data and (iii) a webpage containing information about flow cytometry protocols

ORGANISATION DU GENOME ET RELATIONS EVOLUTIVES ENTRE QUELQUES ESPECES DU GENRE QUERCUS

LES ANALYSES DE DIVERSITE, AINSI QUE LES ETUDES D'ECOLOGIE MOLECULAIRE, MENEES SUR LES CHENES ONT CLAIREMENT MIS EN EVIDENCE LA COMPLEXITE SYSTEMATIQUE AU SEIN DU GENRE QUERCUS. COMME DANS BEAUCOUP DE COMPLEXES D'ESPECES LA DELIMITATION BIOLOGIQUE DES ESPECES N'EST PAS TRANCHEE. EN EFFET, DES INTROGRESSIONS ET DE FLUX DE GENES IMPORTANTS ENTRE ESPECES ONT ETE DECRITS. CEPENDANT, MALGRE LES FLUX DE GENES, LA DIFFERENCIATION AU NIVEAU MORPHOLOGIQUE ENTRE ESPECES RESTE VALIDE. AINSI, ON PEUT CITER UNE ABSENCE REMARQUABLE DE COINCIDENCE ENTRE LA DIFFERENCIATION AU NIVEAU PHENOTYPIQUE ET LA DIFFERENCIATION AU NIVEAU GENETIQUE. CETTE ETUDE EST UNE CONTRIBUTION A LA COMPREHENSION DE LA DIFFERENCIATION INTERSPECIFIQUE ET DES RELATIONS PHYLOGENETIQUES AU SEIN DE CE GENRE. ELLE EST BASEE SUR L'ANALYSE DE L'ORGANISATION DU GENOME AU NIVEAU CHROMOSOMIQUE AINSI QU'AU NIVEAU MOLECULAIRE. UN PANEL DE ONZE ESPECES REPRESENTATIVES DES DIFFERENTS GROUPES PHYLOGENETIQUES ET GEOGRAPHIQUES A ETE ANALYSE. UNE ORGANISATION TRES CONSERVEE DES MARQUEURS D'EVOLUTION CHROMOSOMIQUE (L'HETEROCHROMATINE ET LES GENES RIBOSOMIQUES) A ETE REVELE TOUT EN CONFIRMANT UNE STABILITE CARYOTYPIQUE (LES CARACTERES MORPHOLOGIQUES DES CHROMOSOMES) ET GENOMIQUE (TAILLE DU GENOME) AU SEIN DU GENRE. CETTE REMARQUABLE UNIFORMITE CHROMOSOMIQUE CONSTITUE UN BON EXEMPLE DE SPECIATION SANS REARRANGEMENTS CHROMOSOMIQUES IMPORTANTS. UNE DIFFERENCIATION INTERSPECIFIQUE A ETE RECHERCHEE AU NIVEAU MOLECULAIRE ENTRE DEUX CHENES, Q. ROBUR ET Q. SUBER, EN COMPARANT LEURS GENOMES PAR LA TECHNIQUE REPRESENTATIONAL DIFFERENCE ANALYSIS. DES SEQUENCES DIVERGENTES ENTRE LES DEUX ESPECES APPARTIENNENT A LA FRACTION REPETEE DISPERSEE DU GENOME LIEE AUX RETROTRANSPOSONS. LES RESULTATS FONT L'OBJET D'INTERPRETATION SE PLACANT RESOLUMENT DANS LA POLEMIQUE AUTOUR DE LA SPECIATION DANS LE GENRE QUERCUS. AU-DELA DES RESULTATS RELATIFS A LA DIFFERENCIATION GENOMIQUE, UNE PARTIE DE LA THESE ETUDIE LE POLYMORPHISME DES REGIONS D'ORGANISATEURS NUCLEOLAIRES (NORS), OU SE SITUENT LES GENES CODANT POUR L'ARNR 18S-26S. L'ORIGINE DE LA VARIATION DE LA TAILLE DU NOR EST DUE A LA DECONDENSATION DE LA CHROMATINE RIBOSOMIQUES. L'ETUDE DU DEGRE DE DECONDENSATION NOUS A PERMIS DE SUGGERER UN MODELE D'ORGANISATION STRUCTURALE DE CE LOCUS, ET DE DISCUTER LA DYNAMIQUE DE L'ACTIVITE TRANSCRIPTIONNELLE. ON A SUGGERE QUE LE COMPORTEMENT DE LA CHROMATINE RIBOSOMIQUE DE CE LOCUS CORRESPOND AU MECANISME DE COMPACTION DE LA CHROMATINE NECESSAIRE POUR L'INACTIVATION.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Origine et évolution du génome au sein du complexe d'espèces d'Ipomoea batatas (L.) Lam, la patate douce

Résumé françaisRésumé anglaisORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF