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The large intergenic spacer (IGS) region of rDNA is a valuable DNA sequence because it contains the signals for transcription and processing of rRNAs. In this study, we sequenced and analyzed the complete nucleotide of rDNA IGS region of pomegranate for the first time. This IGS sequence was 3,712 bp in length with GC content of 67.8 %. The sequence analysis indicated that the spacer could be divided into three main regions: a central repetitive region and two flanking unique domains on on both sides of the central area. Central region is composed of two repeat families (A and B), and the third region contained two short direct repeats (C1 and C2). By comparisons with the IGS sequence of other plant species and computer-aided searches, we determined the putative transcription initiation and termination sites, and the large number of methylable sites. The presence of some conserved motifs in this region may play an important role in regulation of rRNA transcription. Taken together, the pomegranate IGS revealed the complex structure. However, its organization and structure are similar to most other rDNA spacers studied. [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]

Almonds and peaches are among the most economically important fruit crops in subtropical and temperate regions. Questions regarding the origin and domestication of the crop species, interspecific relationships, and evolutionary patterns of fruits have remained unanswered due to the lack of phylogenetic data of Prunus subgenus Amygdalus, in which both almond and peach are classified. Twenty-two species of subg. Amygdalus were included in phylogenetic analyses of plastid ndhF- rpl32, rpL16, trnH- psbA, trnL- trnF, trnQ- 5′ rps16, and trnS- trnG and nuclear s6pdh genes to investigate the circumscription of subg. Amygdalus, phylogenetic relationships among the species, and implication for mesocarp and endocarp evolution. Prunus subg. Amygdalus is best circumscribed to include both almonds and peaches, comprising two sections, Amygdalus and Persica. Species traditionally placed close to almonds, such as P. tenella, P. petunnikowii, P. triloba, and P. pedunculata, should be excluded from subg. Amygdalus. Characteristics used to diagnose subg. Amygdalus, such as dry, splitting mesocarp and the ornamentation of endocarp evolved multiple times in Prunus; thus classification based solely on these morphological characters produces a taxonomic scheme that might not represent common ancestry. A dry, splitting mesocarp is likely to be ancestral for the common ancestor of subg. Amygdalus, and the fleshy, non-splitting mesocarp found in peaches was derived from the dry, splitting mesocarp, presumably by domestication and selection for a fleshy fruit in China. Very low genetic divergence among cultivated almond and its close relatives might be associated with gene flow and/or rapid speciation within the group. [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]

The genome size of 265 plants and the GC content of 126 plants from 63 populations of the Cyanus triumfetti and Cyanus montanus groups, collected across the Carpathians, Pannonia, Bohemian Massif, and Western and Dinaric Alps were determined by PI and DAPI flow cytometry. Variation of the nuclear DNA content among homoploid species, and intraspecific and interpopulation variation were confirmed in simultaneous analyses. The 2 C-value at the diploid level (the C. triumfetti group) varied from 2.53 for Cyanus dominii subsp. sokolensis to 3.06 pg for C. triumfetti s.s. (1.21-fold range). At the tetraploid level (the C. montanus group), the 2 C-value varied from 5.19 for Cyanus mollis to 5.84 pg for C. montanus (1.13-fold range). High intraspecific and interpopulation variation in the amount of nuclear DNA in the C. triumfetti group correlates with the extensive morphological variation found in this group. Significant between-species differences in genome size indicate that this attribute may be used as a supportive taxonomic marker for both of the groups studied. The GC content varied by 2.93 %, from 39.46 % for ' Cyanus axillaris' to 40.61 % for Cyanus adscendens; this character is of no value for taxonomic purposes. Genome size of the studied populations is significantly higher in southern parts of the distribution area and at higher elevations. Plants with smaller genomes tend to occur in dry areas at low altitudes with high diurnal and annual temperature oscillations. The GC content of the populations studied is significantly correlated with longitude, increasing from east to west; and plants with GC-rich genomes are concentrated in the coldest areas with low minimum temperatures. [ABSTRACT FROM AUTHOR]