Chromosome identification in the Andean common bean accession G19833 (Phaseolus vulgaris L., Fabaceae)

Characterization of all chromosomes of the Andean G19833 bean genotype was carried out by fluorescent in situ hybridization. Eleven single-copy genomic sequences, one for each chromosome, two BACs containing subtelomeric and pericentromeric repeats and the 5S and 45S ribosomal DNA (rDNA) were used as probes. Comparison to the Mesoamerican accession BAT93 showed little divergence, except for additional 45S rDNA sites in four chromosome pairs. Altogether, the results indicated a relative karyotypic stability during the evolution of the Andean and Mesoamerican gene pools of P. vulgaris

Epigenetic analyses and the distribution of repetitive DNA and resistance genes reveal the complexity of common bean (Phaseolus vulgaris L., Fabaceae) Heterochromatin

The common bean (Phaseolus vulgaris L.) is the main representative of its genus and one of most important sources of proteins in African and Latin American countries. Although it is a species with a small genome, its pericentromeric and subtelomeric heterochromatin fractions are interspersed with single-copy sequences and active genes, suggesting a less compartmentalized genome organization. The present study characterized its chromatin fractions, associating the distribution of repetitive sequences and resistance genes with histone and DNA epigenetic modifications with and without biotic stress. Immunostaining with H3K4me3 and H4K5ac were generally associated with euchromatic regions, whereas H3K9me2, H3K27me1, and 5mC preferentially labeled the pericentromeric heterochromatin. The 45S rDNA and centromeric DNA sequences were hypomethylated as were most of the terminal heterochromatic blocks. The largest of them, which is associated with resistance genes, was also hypomethylated after the plants were infected with virulent and avirulent strains of the fungus Colletotrichum lindemuthianum, suggesting no correlation with control of resistance gene expression. The results highlighted the differences between subtelomeric and pericentromeric heterochromatin as well as variation within the pericentromeric heterochromatin. (C) 2014 S. Karger AG, Base

Waltheria marielleae (Byttnerioideae, Malvaceae), a new species from north-eastern Brazil supported by morphological and phylogenetic evidence

Waltheria marielleae is a new species of Malvaceae endemic to north-eastern Brazil that occurs only in the states of Pernambuco and Alagoas, in areas of Atlantic Forest and Caatinga. It is characterized by cinereous leaves, axillary and sessile to subsessile inflorescences, pallid yellow corollas with apically eciliate petals and fan-plumose stigmas. Material and methods – DNA was extracted from leaf tissue and the markers matK, ndhF, and ITS were amplified using universal primers, with PCR products purified and sequenced. Phylogenetic analysis was performed, including DNA sequences obtained from GenBank. Morphological studies were based on the analysis of specimens deposited in seven herbaria and specimens collected in Pernambuco state, Brazil. Results – Waltheria marielleae is morphologically and phylogenetically related to pantropical W. indica and W. ackermanniana, with these three species forming a well-supported clade. Overall, phylogenetic molecular analysis suggests the monophyly of Waltheria, with the two currently proposed sections also being monophyletic, and Melochia as its sister group. The new species is assessed here as Endangered, according to IUCN criteria. In addition, we formally present new occurrences of W. ackermanniana and W. rotundifolia. Conclusion – In this study, a complete morphological description, illustration, distribution map, and phylogenetic tree are provided for Waltheria marielleae. This species is compared with morphologically and phylogenetically related species (W. ackermanniana, W. indica, and W. rotundifolia) and an identification key to the species occurring in Alagoas and Pernambuco is provided.Fil: Silva Coutinho, Thales. Universidade Federal de Pernambuco; BrasilFil: Sader, Mariela Analía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Pedrosa Harand, Andrea. Universidade Federal de Pernambuco; BrasilFil: Alves, Marccus. Universidade Federal de Pernambuco; Brasi

Plastome sequencing of South American Podocarpus species reveals low rearrangement rates despite ancient gondwanan disjunctions

Background: Historical reconstructions within Podocarpaceae have provided valuable information to disentangle biogeographic scenarios that begun 65 Mya. However, early molecular phylogenies of Podocarpaceae failed to agree on the intergeneric relationships within the family. The aims of this study were to test whether plastome organization is stable within the genus Podocarpus, to estimate the selective regimes affecting plastome protein-coding genes, and to strengthen our understanding of the phylogenetic relationships and biogeographic history. Methods and Results: We sequenced the plastomes of four South American species from Patagonia, southern Yungas, and Brazilian subtropical forests. We compared their plastomes to those published from Brazil, Africa, New Zealand, and Southeast Asia, along with representatives from other genera within Podocarpaceae as outgroups. The four newly sequenced plastomes ranged in size between 133,791 bp and 133,991 bp. Gene content and order among chloroplasts from South American, African and Asian Podocarpus were conserved and different from the plastome of P. totara, from New Zealand. Most genes showed substitution patterns consistent with a conservative selective regime. Phylogenies inferred from either complete sequences or protein coding regions were mostly congruent with previous studies, but showed earlier branching of P. salignus, P. totara and P. sellowii. Conclusions: Highly similar and conserved plastomes of African, South American and Asian species suggest that P. totara plastome should be revised and compared to other species from Oceanic distribution. Furthermore, given such structural conservation, we suggest plastome sequencing is not useful to test whether genomic order can be climatically or geologically structured.Fil: Quiroga, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Zattara, Eduardo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Souza, Gustavo. Universidade Federal de Pernambuco; BrasilFil: Pedrosa Harand, Andrea. Universidad Federal Rural Pernambuco; BrasilFil: Premoli Il'grande, Andrea Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Complex rearrangements are involved in Cephalanthera (Orchidaceae) chromosome evolution

The genus Cephalanthera is an excellent plant group for karyotype evolution studies because it exhibits a dysploid series and bimodal karyotypes. With the aim of understanding their chromosomal and phylogenetic relationships, rRNA genes and the Arabidopsis-type telomeric sequence were mapped by fluorescence in-situ hybridization (FISH), and the rDNA intergenic spacer (ITS) was sequenced for the first time in three European species: C. longifolia (2n = 4x = 32), C. damasonium (2n = 4x = 36) and C. rubra (2n = 4x = 44). One 45S and three 5S rDNA sites are observed in C. longifolia, one 45S and two 5S sites in C. damasonium, and two 45S and one 5S site in C. rubra. Telomeric signals were observed at every chromosome end in all three species and C. damasonium also displays interstitial signals on three chromosome pairs. In agreement with chromosome data, molecular analyses support C. longifolia and C. damasonium as closely related taxa, while C. rubra stands apart. Possible pathways of karyotype evolution are discussed in reference to a previous hypothesis. The results indicate that complex chromosomal rearrangements, possibly involving Robertsonian fusions and fissions, loss of telomeric repeats, gain or loss of rDNA sites and other heterochromatic sequences and inversions, may have contributed to generating the present-day karyotypes.Fil: Moscone, Eduardo Alberto. Universidad de Viena; Austria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Samuel, Rosabelle. Universidad de Viena; AustriaFil: Schwarzacher, Trude. University of Leicester; Reino UnidoFil: Schweizer, Dieter. Universidad de Viena; AustriaFil: Pedrosa-Harand, Andrea. Universidad de Viena; Austri