The genome of the domesticated apple (Malus × domestica Borkh.)

We report a high-quality draft genome sequence of the domesticated apple (Malus × domestica). We show that a relatively recent (>50 million years ago) genome-wide duplication (GWD) has resulted in the transition from nine ancestral chromosomes to 17 chromosomes in the Pyreae. Traces of older GWDs partly support the monophyly of the ancestral paleohexaploidy of eudicots. Phylogenetic reconstruction of Pyreae and the genus Malus, relative to major Rosaceae taxa, identified the progenitor of the cultivated apple as M. sieversii. Expansion of gene families reported to be involved in fruit development may explain formation of the pome, a Pyreae-specific false fruit that develops by proliferation of the basal part of the sepals, the receptacle. In apple, a subclade of MADS-box genes, normally involved in flower and fruit development, is expanded to include 15 members, as are other gene families involved in Rosaceae-specific metabolism, such as transport and assimilation of sorbitol.

Two new species of Saxifraga (Saxifragaceae) from Southwestern China

Two new species, Saxifraga xiaozhongdianensis J. T. Pan and S. ludingensis J. T. Pan, from the Saxifragaceae in China are described and illustrated. Of these, S. xiaozhongdianensis is endemic to Zhongdian, Yunnan, and is related to S. brachyphylla Franchet. It differs from S. brachyphylla in the sepals adaxially dark brown glandular-villose and the petals basally subauriculate. Saxifraga ludingensis occurs in Luding, Sichuan, and is very similar to S. egregioides J. T. Pan and S. stellariifolia Franchet. It differs from S. egregioides in the stems brown glandular-villose, the cauline leaves adaxially brown glandular-villose, the sepals spreading in anthesis and abaxially brown glandular-villose, and the petals 5-veined. It differs from S. stellariifolia in the leaves cordate and abaxially glabrous, the sepals abaxially brown glandular-villose, and the petals 4-callose and 5-veined. Saxifraga xiaozhongdianensis and S. ludingeasis are apparently endemic to western China and belong to Saxifraga sect. Ciliatae Haworth, emend. J. T. Pan.

Floral organogenesis and development of two taxa of the Solanaceae - Anisodus tanguticus and Atropa belladonna

Floral organogenesis and development of two Solanaceae species, Anisodus tanguticus and Atropa belladonna, were studied by using scanning electron microscopy (SEM) as part of a project on systematics and evolution in the tribe Hyoscyameae. These two species share the following common characters of floral organ initiation and development: (1) initiation of the floral organs in the two species follows Hofmeister's rule; (2) the mode of corolla tube development belongs to the "late sympetaly" type, namely, petals are initiated separately and later become joined by fusion of their basal meristem, then rise together and form a corolla tube; (3) primordia of the floral appendages are initiated in a pentamerous pattern and acropetal order: sepals are initiated first, followed by the petals and stamens, and finally the carpels. The whorl of five stamen primordia forms almost simultaneously and originates opposite the sepal primordia, but initiation of the sepal primordia shows different modes in the two species. The sepal primordia of Anisodus tanguticus have simultaneously whorled initiation, while those of Atropa belladonna have helical initiation. The systematic significance of the present results in the genera Anisodus and Atropa is discussed in this paper.

Systematics and floral evolution of the Dialiinae (Caesalpinioideae), a diverse lineage of tropical legumes

Le clade Dialiinae représente l’une des premières lignées de la sous-famille Caesalpinioideae des Leguminosae. Il se compose de 17 genres (environ 90 espèces), avec des taxons qui sont répandus dans toutes les régions tropicales du monde. Morphologiquement, le groupe comprend un assemblage divers de taxons qui peut représenter une «phase expérimentale» dans l’évolution florale des légumineuses. Différents représentants du clade présentent de la poly-, mono-, et asymétrie, et semblent avoir subi un haut degré de perte d’organe, produisant, dans certains cas, des fleurs extrêmement réduites qui sont à peine reconnaissables comme appartenant à la famille des légumineuses. Afin d’obtenir une image plus claire de l’évolution florale du clade Dialiinae, une phylogénie bien résolue et bien soutenue est nécessaire. Dans le but de créer une telle phylogénie, un total de 37 échantillons d’ADN des Dialiinae a été séquencé pour deux régions chloroplastiques, soit rps16 et trnL. De plus, une étude morphologique complète a été réalisée. Un total de 135 caractères végétatifs et reproductifs a été évalué pour 79 espèces de Dialiinae et pour quatre groupes externes. Les analyses phylogénétiques ont d’abord été effectuées sur un groupe restreint de taxons pour lesquels les trois types de données étaient disponibles. Les nœuds fortement soutenus de cette phylogénie ont ensuite été utilisés comme contrainte pour une seconde analyse de parcimonie avec les données morphologiques d’un ensemble plus important de taxons. Les caractères morphologiques ont été optimisés sur l’un des arbres les plus parcimonieux de cette seconde analyse. Un certain nombre de nouvelles relations au niveau de l’espèce ont été résolues, créant une image plus claire quant à l’évolution de la forme florale dans le temps, particulièrement pour les genres Labichea et Dialium. En plus de leur morphologie florale mature diverse, les Dialiinae sont également très variables dans leur ontogénèse florale, affichant à la fois la perte et la suppression des organes, et présentant une variété de modes d’initiation d’organes. Afin de construire une image plus complète du développement floral et de l’évolution dans ce clade, l’ontogénèse florale de plusieurs espèces non documentées à ce jour a été étudiée. La série complète du développement a été compilée pour six espèces de Dialiinae; quatre de Dialium, ainsi que Poeppigia procera et Mendoravia dumaziana. Le mode et le moment de l’initiation des organes étaient pour la plupart uniforme pour toutes les espèces de Dialium étudiés. Tant pour ce qui est des gains ou des pertes d’organes chez Dialium, une tendance est apparente – l’absence d’organe abaxial. Que ce soit pour les sépales ou les étamines, les gains se produisent toujours en position médiane adaxiale, tandis que les étamines et les pétales perdus sont toujours les organes les plus ventraux. Les taxons étudiés ici illustrent le manque apparent de canalisation du développement observé chez les Caesalpinioideae. Cette plasticité ontogénétique est le reflet de la diversité morphologique au niveau des fleurs tel qu’observée dans l’ensemble de la sous-famille. Une des espèces de Dialiinae, Apuleia leiocarpa, produit une inflorescence andromonoïque, une caractéristique qui est unique en son clade et rare dans les légumineuses dans son ensemble. La microscopie optique et électronique ont été utilisées pour entreprendre une étude détaillée de la morphologie florale de ce taxon. On a constaté que tandis que les fleurs hermaphrodites produisent un seul carpelle et deux étamines, les fleurs staminées produisent trois étamines sans toutefois montrer signe de développement du carpelle. Les inflorescences semblent produire près de quatre fois plus de fleurs staminées que de fleurs hermaphrodites, lesquelles occupent toujours la position centrale de l’inflorescence cymeuse. Ce ratio élevé mâle/bisexuel et la détermination précoce du sexe chez Apuleia sont rares chez les Caesalpinioideae, ce qui suggère que l’andromonoecie se développe dans ce genre comme un moyen d’accroître la dispersion du pollen plutôt qu’en réponse à des limitations de ressources.

Systematics and evolution of the genus Deuterocohnia Mez (Bromeliaceae)

The present study investigates the systematics and evolution of the Neotropical genus Deuterocohnia Mez (Bromeliaceae). It provides a comprehensive taxonomic revision as well as phylogenetic analyses based on chloroplast and nuclear DNA sequences and presents a hypothesis on the evolution of the genus. A broad morphological, anatomical, biogeographical and ecological overview of the genus is given in the first part of the study. For morphological character assessment more than 700 herbarium specimens from 39 herbaria as well as living plant material in the field and in the living collections of botanical gardens were carefully examined. The arid habitats, in which the species of Deuterocohnia grow, are reflected by the morphological and anatomical characters of the species. Important characters for species delimitation were identified, like the length of the inflorescence, the branching order, the density of flowers on partial inflorescences, the relation of the length of the primary bracts to that of the partial inflorescence, the sizes of floral bracts, sepals and petals, flower colour, the presence or absence of a pedicel, the curvature of the stamina and the petals during anthesis. After scrutinizing the nomenclatural history of the taxa belonging to Deuterocohnia – including the 1992 syonymized genus Abromeitiella – 17 species, 4 subspecies and 4 varieties are accepted in the present revision. Taxonomic changes were made in the following cases: (I) New combinations: A. abstrusa (A. Cast.) N. Schütz is re-established – as defined by Castellanos (1931) – and transfered to D. abstrusa; D. brevifolia (Griseb.) M.A. Spencer & L.B. Sm. includes accessions of the former D. lorentziana (Mez) M.A. Spencer & L.B. Sm., which are not assigned to D. abstrusa; D. bracteosa W. Till is synonymized to D. strobilifera Mez; D. meziana Kuntze ex Mez var. carmineo-viridiflora Rauh is classified as a subspecies of D. meziana (ssp. carmineo-viridiflora (Rauh) N. Schütz); D. pedicellata W. Till is classified as a subspecies of D. meziana (ssp. pedicellata (W. Till) N. Schütz); D. scapigera (Rauh & L. Hrom.) M.A. Spencer & L.B. Sm ssp. sanctae-crucis R. Vásquez & Ibisch is classified as a species (D. sanctae-crucis (R. Vásquez & Ibisch) N. Schütz); (II) New taxa: a new subspecies of D. meziana Kuntze ex Mez is established; a new variety of D. scapigera is established; (the new taxa will be validly published elsewhere); (III) New type: an epitype for D. longipetala was chosen. All other species were kept according to Spencer and Smith (1992) or – in the case of more recently described species – according to the protologue. Beside the nomenclatural notes and the detailed descriptions, information on distribution, habitat and ecology, etymology and taxonomic delimitation is provided for the genus and for each of its species. An key was constructed for the identification of currently accepted species, subspecies and varieties. The key is based on easily detectable morphological characters. The former synonymization of the genus Abromeitiella into Deuterocohnia (Spencer and Smith 1992) is re-evalutated in the present study. Morphological as well as molecular investigations revealed Deuterocohnia incl. Abromeitiella as being monophyletic, with some indications that a monophyletic Abromeitiella lineage arose from within Deuterocohnia. Thus the union of both genera is confirmed. The second part of the present thesis describes and discusses the molecular phylogenies and networks. Molecular analyses of three chloroplast intergenic spacers (rpl32-trnL, rps16-trnK, trnS-ycf3) were conducted with a sample set of 119 taxa. This set included 103 Deuterocohnia accessions from all 17 described species of the genus and 16 outgroup taxa from the remainder of Pitcairnioideae s.str. (Dyckia (8 sp.), Encholirium (2 sp.), Fosterella (4 sp.) and Pitcairnia (2 sp.)). With its high sampling density, the present investigation by far represents the most comprehensive molecular study of Deuterocohnia up till now. All data sets were analyzed separately as well as in combination, and various optimality criteria for phylogenetic tree construction were applied (Maximum Parsimony, Maximum Likelihood, Bayesian inferences and the distance method Neighbour Joining). Congruent topologies were generally obtained with different algorithms and optimality criteria, but individual clades received different degrees of statistical support in some analyses. The rps16-trnK locus was the most informative among the three spacer regions examined. The results of the chloroplast DNA analyses revealed a highly supported paraphyly of Deuterocohnia. Thus, the cpDNA trees divide the genus into two subclades (A and B), of which Deuterocohnia subclade B is sister to the included Dyckia and Encholirium accessions, and both together are sister to Deuterocohnia subclade A. To further examine the relationship between Deuterocohnia and Dyckia/Encholirium at the generic level, two nuclear low copy markers (PRK exon2-5 and PHYC exon1) were analysed with a reduced taxon set. This set included 22 Deuterocohnia accessions (including members of both cpDNA subclades), 2 Dyckia, 2 Encholirium and 2 Fosterella species. Phylogenetic trees were constructed as described above, and for comparison the same reduced taxon set was also analysed at the three cpDNA data loci. In contrast to the cpDNA results, the nuclear DNA data strongly supported the monophyly of Deuterocohnia, which takes a sister position to a clade of Dyckia and Encholirium samples. As morphology as well as nuclear DNA data generated in the present study and in a former AFLP analysis (Horres 2003) all corroborate the monophyly of Deuterocohnia, the apparent paraphyly displayed in cpDNA analyses is interpreted to be the consequence of a chloroplast capture event. This involves the introgression of the chloroplast genome from the common ancestor of the Dyckia/ Encholirium lineage into the ancestor of Deuterocohnia subclade B species. The chloroplast haplotypes are not species-specific in Deuterocohnia. Thus, one haplotype was sometimes shared by several species, where the same species may harbour different haplotypes. The arrangement of haplotypes followed geographical patterns rather than taxonomic boundaries, which may indicate some residual gene flow among populations from different Deuteroccohnia species. Phenotypic species coherence on the background of ongoing gene flow may then be maintained by sets of co-adapted alleles, as was suggested by the porous genome concept (Wu 2001, Palma-Silva et al. 2011). The results of the present study suggest the following scenario for the evolution of Deuterocohnia and its species. Deuterocohnia longipetala may be envisaged as a representative of the ancestral state within the genus. This is supported by (1) the wide distribution of this species; (2) the overlap in distribution area with species of Dyckia; (3) the laxly flowered inflorescences, which are also typical for Dyckia; (4) the yellow petals with a greenish tip, present in most other Deuterocohnia species. The following six extant lineages within Deuterocohnia might have independently been derived from this ancestral state with a few changes each: (I) D. meziana, D. brevispicata and D. seramisiana (Bolivia, lowland to montane areas, mostly reddish-greenish coloured, very laxly to very densely flowered); (II) D. strobilifera (Bolivia, high Andean mountains, yellow flowers, densely flowered); (III) D. glandulosa (Bolivia, montane areas, yellow-greenish flowers, densely flowered); (IV) D. haumanii, D. schreiteri, D. digitata, and D. chrysantha (Argentina, Chile, E Andean mountains and Atacama desert, yellow-greenish flowers, densely flowered); (V) D. recurvipetala (Argentina, foothills of the Andes, recurved yellow flowers, laxly flowered); (VI) D. gableana, D. scapigera, D. sanctae-crucis, D. abstrusa, D. brevifolia, D. lotteae (former Abromeitiella species, Bolivia, Argentina, higher Andean mountains, greenish-yellow flowers, inflorescence usually simple). Originating from the lower montane Andean regions, at least four lineages of the genus (I, II, IV, VI) adapted in part to higher altitudes by developing densely flowered partial inflorescences, shorter flowers and – in at least three lineages (II, IV, VI) – smaller rosettes, whereas species spreading into the lowlands (I, V) developed larger plants, laxly flowered, amply branched inflorescences and in part larger flowers (I).

Intra-individual variation of flowers in Gunnera subgenus Panke (Gunneraceae) and proposed apomorphies for Gunnerales

A study of inflorescence and flower development in 12 species from four of the six subgenera of Gunnera (Gunneraceae) was carried out. In the species of subgenus Panke, initiation of floral apices along the partial inflorescences is acropetal but ends up in the late formation of a terminal flower, forming a cyme at maturity. The terminal flower is the largest and the most complete in terms of merosity and number of whorls and thus it is the most diagnostic in terms of species-level taxonomy. The lateral flowers undergo a basipetal gradient of organ reduction along the inflorescence, ranging from bisexual flowers (towards the distal region) to functionally (i.e. with staminodia) and structurally female flowers (towards the proximal region). Our results show that the terminal structure in Gunnera is a flower rather than a pseudanthium. The terminal flower is disymmetric, dimerous and bisexual, representing the common bauplan for Gunnera flowers. It has a differentiated perianth with two sepals and two alternate petals, the latter opposite the stamens and carpels. Comparisons with other members of the core eudicots with labile floral construction are addressed. We propose vegetative and floral putative synapomorphies for the sister-group relationship between Gunneraceae and Myrothamnaceae. (C) 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160, 262-283.

HAWAIIAN SKIRT: an F-box gene that regulates organ fusion and growth in arabidopsis

A fast neutron-mutagenized population of Arabidopsis ( Arabidopsis thaliana) Columbia-0 wild-type plants was screened for floral phenotypes and a novel mutant, termed hawaiian skirt ( hws), was identified that failed to shed its reproductive organs. The mutation is the consequence of a 28 bp deletion that introduces a premature amber termination codon into the open reading frame of a putative F-box protein ( At3g61590). The most striking anatomical characteristic of hws plants is seen in flowers where individual sepals are fused along the lower part of their margins. Crossing of the abscission marker, Pro(PGAZAT):beta-glucuronidase, into the mutant reveals that while floral organs are retained it is not the consequence of a failure of abscission zone cells to differentiate. Anatomical analysis indicates that the fusion of sepal margins precludes shedding even though abscission, albeit delayed, does occur. Spatial and temporal characterization, using Pro(HWS):beta-glucuronidase or Pro(HWS):green fluorescent protein fusions, has identified HWS expression to be restricted to the stele and lateral root cap, cotyledonary margins, tip of the stigma, pollen, abscission zones, and developing seeds. Comparative phenotypic analyses performed on the hws mutant, Columbia-0 wild type, and Pro(35S):HWS ectopically expressing lines has revealed that loss of HWS results in greater growth of both aerial and below-ground organs while overexpressing the gene brings about a converse effect. These observations are consistent with HWS playing an important role in regulating plant growth and development.

Floral ontogeny in Polygalaceae and its bearing on the homologies of keeled flowers in Fabales

Keeled flowers are characteristic of many species of Polygalaceae (tribe Polygaleae), in which there is often a distinctive crest located at the abaxial petal. This study of floral ontogeny across the entire family highlights potential suites of characters that relate to the evolution of keeled and crested flowers. One character suite encompasses interconnected transformations of the lateral perianth organs acting as an evolutionary module: bracteoles, lateral sepals (with delayed initiation and petaloid appearance), and lateral petals (suppressed or lost). The plastochron between initiation of the lateral sepals and that of the other sepals is relatively long in the tribe Polygaleae, in which the calyx is usually heteromorphic. By contrast, in the petal whorl, the difference between a zygomorphic and an actinomorphic corolla involves organ suppression rather than heterochrony. Four primary androecial patterns are identified in the family, and the gynoecium ranges between syncarpous‐bicarpellate and multicarpellate. Stigma diversity is based on two primary morphological types: one in which the papillate stigmatic surfaces lie close together, the other in which they are physically separated. The floral ontogeny of Polygalaceae is considered alongside comparative data available for other members of the order Fabales, and hypotheses to account for the similarities and differences between keeled flowers are discussed.

Mass spectrometry imaging of glucosinolates in arabidopsis flowers and siliques

Glucosinolates are multi-functional plant secondary metabolites which play a vital role in plant defence and are, as dietary compounds, important to human health and livestock well-being. Knowledge of the tissue-specific regulation of their biosynthesis and accumulation is essential for plant breeding programs. Here, we report that in Arabidopsis thaliana, glucosinolates are accumulated differentially in specific cells of reproductive organs. Using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI), distribution patterns of three selected compounds, 4-methylsulfinylbutyl (glucoraphanin), indol-3-ylmethyl (glucobrassicin), and 4-benzoyloxybutyl glucosinolates, were mapped in the tissues of whole flower buds, sepals and siliques. The results show that tissue localization patterns of aliphatic glucosinolate glucoraphanin and 4-benzoyloxybutyl glucosinolate were similar, but indole glucosinolate glucobrassicin had different localisation, indicating a possible difference in function. The high resolution images obtained by a complementary approach, cryo-SEM Energy Dispersive X-ray analysis (cryo-SEM-EDX), confirmed increased concentration of sulphur in areas with elevated amounts of glucosinolates, and allowed identifying the cell types implicated in accumulation of glucosinolates. High concentration of sulphur was found in S-cells adjacent to the phloem in pedicels and siliques, indicating the presence of glucosinolates. Moreover, both MALDI MSI and cryo-SEM-EDX analyses indicated accumulation of glucosinolates in cells on the outer surface of the sepals, suggesting that a layer of glucosinolate-accumulating epidermal cells protects the whole of the developing flower, in addition to the S-cells, which protect the phloem. This research demonstrates the high potential of MALDI MSI for understanding the cell-specific compartmentation of plant metabolites and its regulation.

Taxonomic survey of Paepalanthus section Diphyomene (Eriocaulaceae)

Paepalanthus is the largest genus in Eriocaulaceae, comprising about 400 species distributed mainly throughout the Neotropics. Through phylogenetic studies it has been demonstrated that the genus is polyphyletic, although many of its infrageneric categories are monophyletic. In an attempt to clarify the nomenclature and classification of Paepalanthus, we present a taxonomic survey of Paepalanthus section Diphyomene. This group consists of 10 species restricted to South America and is defined by inflorescences being arranged in the form of a tribotryum with terminal dibotryum, a terminal basic unit and pherophylls subtending the lateral dibotrya. Further important distinguishing characteristics are dimerous flowers, pistillate flowers with dolabriform sepals, bifid stigmatic branches and absent staminodes, and staminate flowers with an elongated anthophore. We hereby propose 19 new synonyms, six lectotypifications, one new status, one neotypification and one epitypification.

Croton campanulatus (Euphorbiaceae s.s.), a new species from the Brazilian Atlantic rain forest

Croton campanulatus, a new species from southeastern Brazil in the states of Minas Gerais and Rio de Janeiro, is here described and illustrated. Morphological data indicate that this species belongs to Croton section Cleodora based on its arborescent habit, pistillate flowers with imbricate sepals, reduced petals, and multifid styles that are fused at the base.

Molecular phylogenetics and character evolution of the ""sacaca"" clade: Novel relationships of Croton section Cleodora (Euphorbiaceae)

Phylogenetic relationships of Croton section Cleodora (Klotzsch) Baill. were evaluated using the nuclear ribosomal ITS and the chloroplast trnl-F and trnH-psbA regions. Our results show a strongly supported clade containing most previously recognized section Cleodora species, plus some other species morphologically similar to them. Two morphological synapomorphies that support section Cleodora as a clade include pistillate flowers in which the sepals overlap to some degree, and styles that are connate at the base to varying degrees. The evolution of vegetative and floral characters that have previously been relied on for taxonomic decisions within this group are evaluated in light of the phylogenetic hypotheses. Within section Cleodora there are two well-supported clades, which are proposed here as subsections (subsection Sphaerogyni and subsection Spruceani). The resulting phylogenetic hypothesis identifies the closest relatives of the medicinally important and essential oil-rich Croton cajucara Benth. as candidates for future screening in phytochemical and pharmacological studies. (C) 2011 Elsevier Inc. All rights reserved.

Morfologia floral e biologia reprodutiva de genótipos de aceroleira

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

Estruturas secretoras de mucilagem em Hibiscus pernambucensis Arruda (Malvaceae): distribuição, caracterização morfoanatômica e histoquímica

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

Coléteres dendróides em Alibertia sessilis (Vell.) K. Schum., uma espécie não-nodulada de Rubiaceae

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