Nelson Ivo Matzenbacher

AFLP Phylogeny of South American Species of Hypochaeris (Asteraceae, Lactuceae)

Abstract Hypochaeris is thought to have arrived in South America by dispersal over the Atlantic Ocean from NW Africa during the Pliocene or Pleistocene. We used amplified fragment length polymorphism (AFLP) to unravel specific limits and relationships in the South American group of Hypochaeris (c. 45 species). The Moroccan endemic Hypochaeris angustifolia, which is sister to the entire South American group, was used as outgroup. Our AFLP analysis comprises 415 individuals from 32 South American species and is based on six primer combinations with 670 fragments scored. It provides important information for the delimitation of species and detection of closely related species pairs or groups. Most species are monophyletic and supported with > 90% bootstrap proportion. Hybridization is suggested between Hypochaeris chillensis and H. microcephala in Brazil. The internal nodes (or “backbone”) of the tree are not highly supported, but six major phylogenetic groups (also showing similarity in distribution and growth form) center around Hypochaeris apargioides, H. chondrilloides, H. microcephala, H. pampasica, H. sessiliflora, and H. tenuifolia. These results suggest that rapid migration into different geographical regions played an important role in the initial diversification of Hypochaeris in South America.

Investigation of the essential oil from eight species of Baccharis belonging to sect. Caulopterae (Asteraceae, Astereae): a taxonomic approach

Essential oils of B. articulata, B. crispa, B. microcephala, Baccharis milleflora, B. myriocephala, B. stenocephala, B. trimera and B. usterii, all of sect. Caulopterae, have been analyzed by GC and GC/MS. Despite the morphological similarity among these species, differences in composition of their essential oil obtained by hydrodistillation and hexane extract could be observed. Special attention was given to Baccharis trimera and B. crispa since their differentiation during early stages is not possible due to the absence of synflorescences. Carquejyl acetate is suggested as a marker for Baccharis trimera, and a fast method of detection of this compound is given.

Chromosomal organization and phylogenetic relationships in Hypochaeris species (Asteraceae) from Brazil

The association of cytogenetic and molecular techniques has contributed to the analysis of chromosome organization and phylogeny in plants. The fluorochrome GC-specific CMA 3 , fluorescent in situ hybridization (FISH) and RAPD (Random Amplified Polymorphic DNA) markers were used to investigate chromosome structure and genetic relationships in Hypochaeris (Asteraceae). Seven species native to South America, and two species introduced from Europe (H. glabra and Hypochaeris sp) were studied. FISH with rDNA probes identified one or two loci of 18S-5.8S-25S rDNA in the South American Hypochaeris species and one locus in the European species. Only one 5S rDNA locus was seen in all species studied. Blocks of GC-rich heterochromatin (CMA-positive bands) associated to 18S-5.8S-25SrDNA loci were detected in all species investigated. Co-location of 5S rDNA and CMA bands was also observed, except for three South American species and Hypochaeris sp. In two South American species, additional CMA bands not related to rDNA were observed on the long arm of chromosome 2, near to the centromere. Hypochaeris glabra exhibited additional CMA-positive signals distributed at pericentromeric regions, on the short arms of all chromosomes. A total of 122 RAPD markers were used to determine the genetic relationships among species. The level of polymorphism was very high, revealing two genetic groups comprising the South American and the European species, thus supporting a previous hypothesis of monophyly of the South American Hypochaeris species. The coefficients of genetic similarity between European and South American species were 0.35, on average. Polymorphism was also high within the two groups. The genetic associations observed with RAPD markers were consistent with chromosome characteristics. Species carrying similar distribution of 45S rDNA loci and CMA-positive signals were included in the same group revealed by RAPDs. Cytogenetic and molecular data support the view that not only chromosome rearrangements, but also changes in DNA sequence took place during the diversification of the South American Hypochaeris species.

Composition of essential oils and secretory structures of Baccharis anomala, B. megapotamica and B. ochracea

The chemical composition of the essential oils and the anatomical structures of the aerial parts from Baccharis anomala, B. megapotamica and B. ochracea growing in Brazil were studied. The volatile constituents isolated by hydrodistillation were analyzed by gas chromatograph coupled to a mass spectrometer detector (GC-MSD) and gas chromatograph coupled to a flame ionization detector (GC-FID). The botanical material was fixed, sectioned and prepared according to light and scanning microtechniques. The essential oil from B. anomala yielded 0.18% and showed α-acorenol (16.0%), spathulenol (13.3%) and caryophyllene oxide (12.1%) as the main components. Spathulenol (28.0% and 37.1%) and caryophyllene oxide (20.4% and 30.8%) represented the major constituents of the essential oils from B. megapotamica (yield = 0.17%) and B. ochracea (yield = 0.18%), respectively. The leaves and stems of these Baccharis species showed non-glandular trichomes and secretory ducts. Glandular trichomes were also found on the vegetative aerial parts of B. megapotamica

O progresso da pesquisa sobre o gênero Baccharis, Asteraceae: I - Estudos botânicos

Baccharis is an important genus of the Asteraceae family, which comprises about 500 American species, including 120 species from Brazil. Several authors such as De Candolle, Baker, Heering, Cuatrecasas, Ariza Espinar, Barroso and Giuliano have attempted to elaborate an adequate genus division in subgenera and sections. Baccharis species are economically important since they help to prevent erosion and are employed as ornamental plants, although they can become weeds of difficult control in grazing and poison to the cattle. However, in the folk medicine, many species are relevant and have been studied, aiming to contribute to their morpho-anatomical and quality control knowledge.

Chromosomal polymorphism in 12 populations of Mikania micrantha (Compositae)

Mikania micrantha is a climbing perennial weed of the family Asteraceae, with a vast distribution from South America to south of the United States. This species is widely distributed throughout Brazil, where it shows little morphological variation. Mitotic chromosomes of 12 populations of M. micrantha derived from several Brazilian sites were studied using Feulgen staining and C-banding. The populations included eight diploid (2n = 36 and 42) and four tetraploid (2n = 72) cytotypes. Chromosome numbers of 2n = 36 and 2n = 42 are reported for the first time for M. micrantha. These populations had a secondary constriction in the middle of the larger arm of chromosome pair 1, following the same pattern described for all Mikania species analyzed so far. Numerical and structural variation of the chromosomes was quite common among the karyotypes and nearly all cytotypes differed from each other in some aspect. Most of the chromosomal differentiation may be attributed to inversions and addition or deletion of DNA fragments. C-banding, applied to three of the 12 populations, also revealed polymorphism in the distribution of heterochromatin. Additionally, one to 14 supernumerary or B-chromosomes were observed. The Bs were detected in six of the 12 populations and varied in size, number, and structure among karyotypes and also among cells of the same root meristem. The B chromosomes were also heterochromatic, showing a C-banding pattern similar to the A chromosomes, and suggesting that they may be derived from the chromosomes of the A complement.

Characterization, genomic organization and chromosomal distribution of Ty1-copia retrotransposons in species of Hypochaeris (Asteraceae)

This study aims to analyze the diversity of Ty1-copia retrotransposons in 18 taxa of Hypochaeris, including two Old World species H. maculata (2n=2x=10) and H. angustifolia (2n=2x=8), and representatives of the South American species (16 accessions of 15 species; all 2n=2x=8). Analysis of 380 PCR-amplified sequences, corresponding to a conserved domain of the subset of Ty1-copia reverse transcriptase (rt) gene amplifiable with degenerate standard primers, showed high levels of intra- and interspecific heterogeneity. Nucleotide diversity (Pi) of the copia fragments was high in all species and varied from 0.229 (H. angustifolia) to 0.412 (H. chillensis). Higher sequence heterogeneity correlates positively with larger genome size among analyzed species. Phylogenetic analyses of amplified fragments revealed different patterns of intraspecific heterogeneity within species, with most sequences forming one well-supported main clade while a few sequences fall into small clades or are left ungrouped. The combined analysis of all sequences revealed the presence of three main clades and showed that highly diverged species contain closely related Tyl-copia group retrotransposons. One of the main clades includes rt sequences of all South American species and three sequences of their putative ancestor, H. angustifolia, but no sequence of the Old World H. maculata. FISH with copia retrotransposons in four Hypochaeris species, including H. maculata and H. angustifolia and New World H. apargioides and H. spathulata, revealed differences in the chromosomal distribution between the two groups. In Old World species copia retroelements are distributed over the whole length of the chromosomes, excluding rDNA sites and some centromeres. In the South American species the two largest chromosome pairs are enriched in copia, while most of the long arms of the two small pairs of chromosomes are devoid of these elements. The patterns of heterogeneity and chromosomal distribution of Ty1-copia retrotransposons in Hypochaeris are discussed in the context of the origin, genome evolution and organization of the South American species.

Chemical composition of volatiles from male and female specimens of Baccharis trimera collected in two distant regions of southern brazil: a comparative study using chemometrics

GC/MS/FID analyses of volatile compounds from cladodes and inflorescences from male and female specimens of Baccharis trimera (Less.) DC. collected in the states of Parana and Santa Catarina, Brazil, showed that carquejyl acetate was the primary volatile component (38% to 73%), while carquejol and ledol were identified in lower concentrations. Data were subjected to hierarchical cluster analysis and principal component analysis, which confirmed that the chemical compositions of all samples were similar. The results presented here highlight the occurrence of the same chemotype of B. trimera in three southern states of Brazil.

Screening of Brazilian plants for the presence of peroxides

Chloroform or dichloromethane extracts of 357 southern Brazilian plant species were tested for the presence of peroxides by thinlayer chromatography, using the spray reagent from Huber & Frohlke. From the species tested, 71 (20%) showed positive results and most of them (56%) are Asteraceae species. The species tested were mainly from Asteraceae, but 55 more families were screened, in a total of 77 genera surveyed.

Distribution of coumarins in the tribe Plucheeae, genus Pterocaulon

gilsane@farmacia.ufrgs.br; 2) PPG-Botanica, ICBS, 91509-900 Porto Alegre, RS, Brazil, fax (051) 33167670; 3) Grupo Metabolomica, LCQUI/CCT, Universidade Estadual do Norte Fluminense, 28015-620 Campos dos Goytacazes, RJ, Brazil; 4) Faculte de Pharmacie, Universite de Picardie Jules Verne, 80037 Amiens, France. Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 572-574, November-December, 2007. Original article submitted August 1, 2006.