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The genus Dyckia (Bromeliaceae) comprises more than 150 terrestrial or epilithic species with a strongly xeromorphic habit. Most of its members belong to the azonal rock vegetation of Neotropical savannas and forests of Brazil and adjacent countries. Dyckia is relatively species-rich compared with its closest relatives Encholirium (27 species) and Deuterocohnia (17 species). Here, we present the first molecular phylogenetic analysis of Dyckia using DNA sequence data from six plastid loci ( matK gene, rps16 intron, petD intron, rpl32- trnL, rps16- trnK and trnD- trnT) and a portion of the nuclear gene phyC. A total of 124 accessions were included, corresponding to 79 taxa from six genera. Phylogenetic trees were generated using parsimony, likelihood and Bayesian methods. DNA sequence variation among Dyckia species turned out to be extremely low, and phylogenies were poorly resolved. The monophyly of Dyckia is supported, whereas evidence is provided that Encholirium is paraphyletic. Based on a dated plastid DNA tree, Dyckia experienced a recent radiation starting around 2.9 million years ago. Four major clades could be identified that roughly correspond to the geographic origin of the samples. A parsimony network based on plastid DNA haplotypes shows a star-like pattern, indicating recent range expansions. Our data are compatible with a scenario where Dyckia and Encholirium diverged in northeastern Brazil, whereas one lineage of Dyckia dispersed to southern Brazil from where a rapid colonization of suitable habitats was initiated. We discuss our results in relation to species delimitation in Dyckia. [ABSTRACT FROM AUTHOR]

Pisum sativum was one of the first plants for which the mitotic karyotype was recognized and the karyogram assembled. These achievements were required owing to the physical mapping of P. sativum, providing data for evolutionary approaches and breeding programs. In spite of significant advances, precise morphometric characterization of chromosomes and karyogram assembly of P. sativum have become a topical problem. The present study proposes an unambiguous classification for the chromosomes of P. sativum, based on classical cytogenetic rules and chromosomal DNA amount. Cytogenetic procedure yielded mitotic cells showing morphologically preserved and stoichiometrically stained chromosomes. Twelve mitotic cells were selected, and the mean values for total, short- and long-arm lengths and DNA amount were measured for each chromosome. Chromosomal DNA amount fully correlated with total chromosome length, whose value proportionally decreases with the amount of DNA. Considering these data, all seven chromosomes could be unambiguously identified, yielding a new cytogenetic classification for P. sativum chromosomes. Moreover, the chromosome pairs were ordered according to the classical cytogenetic rule for assembly of karyograms. Since P. sativum is considered a model plant, it was possible to correlate the newly outlined karyotype with other cytogenetic data and linkage groups. [ABSTRACT FROM AUTHOR]

Crocussativus L. is a sterile species (3 n) whose origin has not been yet clarified. A lot of morphological studies supported the theory that it would have been originated from the evolution, or the hybridization, of other Crocus exemplars, especially C. thomasii, C. hadriaticus and C. cartwrightianus. Crocus sativus stigmas are saffron raw source but, because of their high economic value, sometimes this spice is adulterated. By the application of the DNA barcode technique, we analyzed different Crocus species genomes and we partially clarified some aspects of the phylogeny of this genus: in particular, C. sativus possible genetic derivation was elucidated. Our results also showed that different C. sativus species might have evolved by independent events, probably due to several geographical pressures. We demonstrated that barcoding method, usually adopted for interspecific taxonomic identification, could be also applied to intraspecific and population studies. Finally, we proposed this molecular approach as scientific tool able to discriminate and certificate saffron authenticity. [ABSTRACT FROM AUTHOR]

Dianthus polylepis complex consists of two already known endemic species, Dianthus polylepis and D. binaludensis, in Khorassan-Kopetdagh floristic province. The taxonomic position of these species has long been debated. The aim of the present study is to shed light on the evolutionary relationships of the members of the complex using morphological and molecular data. In morphological study, firstly, 56 vegetative and floral characters were measured on 33 specimens of the both species. Multivariate analyses were performed on 25 (out of 56) significantly discriminating morphological traits. In molecular study, we sequenced alleles obtained from a region between 2nd and 6th exons of the gene coding for the enzyme dihydroflavonol 4-reductase copy1 (DFR1). Morphological results show that most of a priori identified accessions were not grouped in a posteriori classification. It is difficult to discriminate D. polylepis from D. binaludensis in morphological continuum among the accessions. Results obtained from the molecular data indicated no monophyly for the members of the D. polylepis complex. Consistency between the morphological and molecular results shows that D. polylepis and D. binaludensis were not morphologically and molecularly well differentiated. Therefore, we propose a new combination as D. polylepis subsp. binaludensis. [ABSTRACT FROM AUTHOR]

Recent studies have proposed a monophyletic circumscription of Filago and a new subgeneric treatment for this genus. The aim of this study was to analyse the nuclear genome size in a phylogenetic framework in order to evaluate the systematic significance of this trait to provide insights into the dynamics of genome size evolution and to assess relationships among DNA content, specific life and ecological features within the study group. A holoploid genome size of 76 samples corresponding to 27 taxa was determined using flow cytometry, which represents the first estimates of genome size in Bombycilaena, Filago, Ifloga and Logfia. Chromosome counts were performed for six species. Parsimony and Bayesian analysis of ITS, ETS and rpl32- trnL intergenic spacer sequence data were used to construct molecular phylogenetic trees. The evolution of genome size was investigated troughout the Brownian motion model with the three scaling parameters λ, κ and δ. The mean 2 C-value in the Filago group is relatively low (1.3644 ± 0.0079 pg) and homogeneous among species. A high degree of congruence was found between genome size distribution and the major phylogenetic lineages obtained. The generally accepted assumption that annual, ephemeral and autogamous species show low genome sizes was confirmed. Also the relatively high DNA contents found for a couple of species could be correlated with their highly specific ecological requirements. Phylogeny seems to represent the most important factor explaining the pattern of DNA amount variation in the Filago group. The DNA amount does not seem to be strongly influenced by selection. [ABSTRACT FROM AUTHOR]