Phylogeny of Celastraceae Subfamily Salacioideae and Tribe Lophopetaleae Inferred from Morphological Characters and Nuclear and Plastid Genes

The phylogeny of Celastraceae subfamily Salacioideae (ca. 255 species in the Old and New World tropics) and tribe Lophopetaleae (ca. 29 species in southern Asia and the Austral-Pacific) was inferred using morphological characters together with plastid (matK, trnL-F) and nuclear (ITS and 26S rDNA) genes. Brassiantha, a monotypic genus endemic to New Guinea, is inferred to be more closely related to the clade of Dicarpellum (New Caledonia) and Hypsophila (Queensland, Australia) than it is to Hippocrateoideae or Salacioideae. This unambiguously supported resolution indicates that a nectary disk positioned outside the stamens has been convergently derived in these two lineages. The clade of Kokoona and Lophopetalum is resolved as more closely related to Breria and Elaeodendron than it is to Hippocrateoideae or Salacioideae. Sarawakodendron, a monotypic genus endemic to Borneo, is resolved as sister to Salacioideae. Salacioideae are inferred to have an Old World origin that was followed by a single successful radiation within Central and South America. We infer that capsular fruits are primitive within the clade of Hippocrateoideae + Sarawakodendron + Salacioideae, with berries a synapomorphy for Salacioideae. Based on the resolution of Sarawakodendron as sister to Salacioideae, we hypothesize that the filaments of Sarawakodendron arils are homologous to the spiral filaments in the mucilagenous pulp of Salacioideae.

Phylogeny of Celastraceae subfamily Hippocrateoideae inferred from morphological characters and nuclear and plastid loci

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The floral nectary of Hymenaea stigonocarpa (Fabaceae, caesalpinioideae): Structural aspects during floral development

Background and Aims Considering that few studies on nectary anatomy and ultrastructure are available for chiropterophilous flowers and the importance of Hymenaea stigonocarpa in natural 'cerrado' communities, the present study sought to analyse the structure and cellular modifications that take place within its nectaries during the different stages of floral development, with special emphasis on plastid dynamics.Methods For the structural and ultrastructural studies the nectary was processed as per usual techniques and studied under light, scanning and transmission electron microscopy. Histochemical tests were employed to identify the main metabolites on nectary tissue and secretion samples.Key Results The floral nectary consists of the inner epidermis of the hypanthium and vascularized parenchyma. Some evidence indicates that the nectar release occurs via the stomata. The high populations of mitochondria, and their juxtaposition with amyloplasts, seem to be related to energy needs for starch hydrolysis. Among the alterations observed during the secretory phase, the reduction in the plastid stromatic density and starch grain size are highlighted. When the secretory stage begins, the plastid envelope disappears and a new membrane is formed, enclosing this region and giving rise to new vacuoles. After the secretory stage, cellular structures named 'extrastomatic bodies' were observed and seem to be related to the nectar resorption.Conclusions Starch hydrolysis contributes to nectar formation, in addition to the photosynthates derived directly from the phloem. In these nectaries, the secretion is an energy-requiring process. During the secretion stage, some plastids show starch grain hydrolysis and membrane rupture, and it was observed that the region previously occupied by this organelle continued to be reasonably well defined, and gave rise to new vacuoles. The extrastomatic bodies appear to be related to the resorption of uncollected nectar.

Can sieve-element plastids in Panicum maximum (Poaceae) leaves act in the blockage of injured sieve-tube elements?

The ultrastructural features and the plastid changes caused by sample preparation were studied in sieve elements of Panicum maximum leaves. Samples of expanded leaves, taken near the ligule region, were fixed and processed by common light and transmission electron microscopy methods. In mature sieve-tube elements, the protoplast is electron-translucent and plastids are the most frequent organelles. Mitochondria and smooth endoplasmic reticulum segments are also visible and occupy a parietal position within the cell. The plastids are globular and show electron-dense proteinaceous inclusions in the stroma. The protein crystals are predominantly cuneate, but thin crystalloids and amorphous and/or filamentous proteins also occur. The presence of intact plastids plus others in different phases of plastid envelope rupture were interpreted as evidence that this rupture is a normal event in response to injury. This plastid envelope rupture is possibly activated by the release of pressure in the sieve-tube element. After plastid membrane vesiculation, the stroma and the protein crystals are dispersed within the sieve-element ground cytoplasm. The vesicles originating from the plastid envelope move to one cell pole, while protein crystalloids move to the opposite pole and agglomerate in the sieve-plate region. Our findings indicate that these protein crystalloids, which deposit in the sieve plate, may act in sieve-plate pores occlusion, preventing the release of phloem sap, similar to the role of P-protein in dicotyledons. (c) 2008 Elsevier GmbH. All rights reserved.

Delimitation of the Segregate Genera of Maytenus s. l. (Celastraceae) Based on Morphological and Molecular Characters

Maytenus s. l. (including Gymnosporia) is a morphologically diverse genus of about 300 species that is widely distributed in the tropics and subtropics of both the Old and New Worlds. Its delimitation has been extensively debated and despite the segregation of Gymnosporia, Maytenus s. s. remains a heterogeneous, polyphyletic group. To delimit natural segregate genera we increased taxon sampling and generated sequences from two nuclear gene regions (ITS and 26S rDNA) and two plastid loci (matK and trnL-F) to analyze together with morphological characters. Both Moya and Tricerma were found to be nested within the New World Maytenus and are recognized as synonyms of Maytenus s. s.. In contrast, the three New World species of Gymnosporia are recognized as a new genus that is closely related to Gyminda. Haydenia is erected for these three species: H. gentryi, H. haberiana, and H. urbaniana. One or more previously proposed or novel genera are required to accommodate the systematically difficult African Maytenus. Putterlickia, and most likely Gloveria, are nested within Gymnosporia and should be synonymized with that genus. New binomials are required for four Chinese and one Rapan species of Gymnosporia that have been previously treated only as Maytenus: Gymnosporia austroyunnanensis, G. confertiflora, G. dongfangensis, G. guangxiensis, and G. pertinax. Austral-Pacific Maytenus are transferred to Denhamia, requiring eight new binomials: Denhamia bilocularis, D. cunninghamii, D. cupularis, D. disperma, D. fasciculiflora, D. ferdinandii, D. fournieri, and D. silvestris. Existing intrageneric classifications of Gymnosporia and Maytenus s. s. were not supported in their entirety. Gymnosporia is inferred to have had an African origin followed by dispersals to Madagascar, southeast Asia and the Austral-Pacific.

Phylogenetic relationships in Kumanoa (Batrachospermales, Rhodophyta) species in Brazil with the proposal of Kumanoa amazonensis sp nov.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Molecular systematics of Thorea (Rhodophyta, Thoreales) species in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sequenciamento de DNA de nova geração e suas aplicações na genômica de plantas

As plataformas de sequenciamento de nova geração são uma alternativa poderosa para estudos de genômica estrutural e funcional. Na genômica de plantas, os trabalhos com as novas plataformas têm sido destinados ao sequenciamento de transcritos, ressequenciamento ou sequenciamento de novo de genomas plastidiais. Neste trabalho, são detalhadas as tecnologias das plataformas mais utilizadas atualmente, bem como é revisada a aplicação dessas tecnologias na genômica estrutural e funcional de plantas.

Phylogenetic relationship of Sirodotia species (Batrachospermales, Rhodophyta) in North and South America

Sequence data from the RUBISCO large subunit (rbcL) plastid gene and nuclear small-subunit ribosomal DNA (SSU rDNA) were examined for five samples of Sirodotia delicatula from southeastern Brazil. Data from six North American samples previously identified as S. huillensis and S. suecica were also included in the analysis. Molecular data supported the continued recognition of these three species as separate entities, although one of the North American collections was misidentified. These results were shown to be congruent with morphology, chromosome number and geographic distribution. S. delicatula is more closely related to S. huillensis, both occurring in tropical-subtropical regions, than either to S. suecica with a temperate-boreal distribution. There was little rbcL variation within S. delicatula from Brazil and Costa Rica (the latter a collection previously identified as S. huillensis), with the six samples sequenced diverging from each other by 0-8 bp (0-0.67%). SSU rDNA data set did not provide sufficient resolution to infer phylogenetic relationships among the species of this group due to the low rates of variation (5 bp). Sirodotia was a well-supported clade (100% bootstrap or 1.00 a posteriori probability) based on rbcL sequences. Thus, the results confirm that Sirodotia is a monophyletic group within the Batrachospermales and we continue to recognize it at the generic level. The species S. delicatula, S. huillensis and S. suecica are morphologically and genetically distinct.

PHYLOGENETIC AFFINITIES of "CHANTRANSIA" STAGES IN MEMBERS of THE BATRACHOSPERMALES and THOREALES (RHODOPHYTA)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Contrasting intra versus interspecies DNA sequence variation for representatives of the Batrachospermales (Rhodophyta): Insights from a DNA barcoding approach

Sixty-five accessions of the species-rich freshwater red algal order Batrachospermales were characterized through DNA sequencing of two regions: the mitochondrial cox1 gene (664 bp), which is proposed as the DNA barcode for red algae, and the UPA (universal plastid amplicon) marker (370 bp), which has been recently identified as a universally amplifying region of the plastid genome. upgma phenograms of both markers were consistent in their species-level relationships, although levels of sequence divergence were very different. Intraspecific variation of morphologically identified accessions for the cox1 gene ranged from 0 to 67 bp (divergences were highest for the two taxa with the greatest number of accessions; Batrachospermum helminthosum and Batrachospermum macrosporum); while in contrast, the more conserved universal plastid amplicon exhibited much lower intraspecific variation (generally 0-3 bp). Comparisons to previously published mitochondrial cox2-3 spacer sequences for B. helminthosum indicated that the cox1 gene and cox2-3 spacer were characterized by similar levels of sequence divergence, and phylogeographic patterns based on these two markers were consistent. The two taxa represented by the largest numbers of specimens (B. helminthosum and B. macrosporum) have cox1 intraspecific divergence values that are substantially higher than previously reported, but no morphological differences can be discerned at this time among the intraspecific groups revealed in the analyses. DNA barcode data, which are based on a short fragment of an organellar genome, need to be interpreted in conjunction with other taxonomic characters, and additional batrachospermalean taxa need to be analyzed in detail to be able to draw generalities regarding intraspecific variation in this order. Nevertheless, these analyses reveal a number of batrachospermalean taxa worthy of more detailed DNA barcode study, and it is predicted that such research will have a substantial effect on the taxonomy of species within the Batrachospermales in the future.

MOLECULAR PHYLOGENY of THE GENUS KUMANOA (BATRACHOSPERMALES, RHODOPHYTA)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Biosynthetic origin of the isoprene units in chromenes of Piper aduncum (Piperaceae)

Metabolic studies involving the incorporation of [1-13C]-D- glucose into intact leaves of Piper aduncum (Piperaceae) have indicated that both the mevalonate (MVA) and the pyruvate-triose (MEP) non-mevalonate pathways are implicated in the biosynthesis of isoprene moieties present in methyl 2,2-dimethyl-2H-1-chromene-6-carboxylate (1) and methyl 2,2-dimethyl-8- (3′-methyl-2′-butenyl)-2H-1-chromene-6-carboxylate (2). The pattern of incorporation of label from [1-13C]-D-glucose into these chromenes was determined by quantitative 13C NMR spectroscopy. The results confirmed that biosynthetic compartment of 1 and 2 could either be the plastid and/ or the cytosol or, possibly, an additional compartment such as the plastid inter-membrane space. ©2007 Sociedade Brasileira de Química.

Phylogeographic Structure And Outbreeding Depression Reveal Early Stages Of Reproductive Isolation In The Neotropical Orchid Epidendrum Denticulatum

Phylogeographic studies provide an important framework for investigating the mechanisms operating during the earliest stages of speciation, as reproductive barriers can be examined among divergent lineages in a geographic context. We investigated the evolution of early stages of intrinsic postmating isolation among different populations and lineages of Epidendrum denticulatum, a Neotropical orchid distributed across different biomes in South America. We estimated genetic diversity and structure for both nuclear and plastid markers, using a haplotype network, differentiation tests, Bayesian assignment analysis, and divergence time estimates of the main lineages. Reproductive barriers among divergent lineages were examined by analyzing seed viability following reciprocal crossing experiments. Strong plastid phylogeographic structure was found, indicating that E. denticulatum was restricted to multiple refuges during South American forest expansion events. In contrast, significant phylogeographic structure was not found for nuclear markers, suggesting higher gene flow by pollen than by seeds. Large asymmetries in seed set were observed among different plastid genetic groups, suggesting the presence of polymorphic genic incompatibilities associated with cytonuclear interactions. Our results confirm the importance of phylogeographic studies associated with reproductive isolation experiments and suggest an important role for outbreeding depression during the early stages of lineage diversification. © 2013 The Society for the Study of Evolution.

Diversidade específica e de hábitat dos Cosmarium de parede lisa (Zygnemaphyceae) do estado de São Paulo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)