119 research outputs found

    Ancestral chemotypes of cultivated grapevine with resistance to Botryosphaeriaceae-related dieback allocate metabolism towards bioactive stilbenes

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    - Grapevine trunk diseases have devastating consequences on vineyards worldwide. European wild grapevines (Vitis vinifera subs. sylvestris) from the last viable population in Germany along the Rhine river showed variable degrees of resistance against Neofusicoccum parvum (strain Bt‐67), a fungus associated with Botryosphaeriaceae‐related dieback. - Representative genotypes from different subclades of this population were mapped with respect to their ability to induce wood necrosis, as well as their defence responses in a controlled inoculation system. - The difference in colonization patterns could be confirmed by cryo‐scanning electron microscopy, while there was no relationship between vessel diameter and infection success. Resistant lines accumulated more stilbenes, that were in addition significantly partitioned to nonglycosylated viniferin trimers. By contrast, the susceptible genotypes accumulated less stilbenes with a significantly higher proportion of glycosylated piceid. - We suggest a model in which in the resistant genotypes phenylpropanoid metabolism is channelled rapidly and specifically to the bioactive stilbenes. Our study specifies a resistant chemotype against grapevines trunk diseases and paves a way to breed for resistance against grapevine Botryosphaeriaceae‐related dieback

    A new Late Agenian (MN2a, Early Miocene) fossil assemblage from Wallenried (Molasse Basin, Canton Fribourg, Switzerland)

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    Excavations of two fossiliferous layers in the Wallenried sand- and marl pit produced a very diversified vertebrate fauna. New material allows the reassessment of the taxonomic position of the ruminant taxa Andegameryx andegaviensis and endemic Friburgomeryx wallenriedensis. An emended diagnosis for the second species is provided and additional material of large and small mammals, as well as ectothermic vertebrates, is described. The recorded Lagomorpha show interesting morphological deviations from other Central European material, and probably represent a unique transitional assemblage with a co-occurrence of Titanomys, Lagopsis and Prolagus. Rodentia and Eulipotyphla belong to typical and well-known species of the Agenian of the Swiss Molasse Basin. Abundant small mammal teeth have allowed us to pinpoint the biostratigraphic age of Wallenried to late MN2a. The biostratigraphic age conforms to data derived from the charophyte assemblages and confirms the oldest occurrence of venomous snake fangs. The palaeoenvironmental context is quite complex. Sedimentary structures and fauna (fishes, frogs, salamanders, ostracods) are characteristic for a humid, lacustrine environment within a flood plain system

    Re-Evaluation of Sinocastor (Rodentia: Castoridae) with Implications on the Origin of Modern Beavers

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    The extant beaver, Castor, has played an important role shaping landscapes and ecosystems in Eurasia and North America, yet the origins and early evolution of this lineage remain poorly understood. Here we use a geometric morphometric approach to help re-evaluate the phylogenetic affinities of a fossil skull from the Late Miocene of China. This specimen was originally considered Sinocastor, and later transferred to Castor. The aim of this study was to determine whether this form is an early member of Castor, or if it represents a lineage outside of Castor. The specimen was compared to 38 specimens of modern Castor (both C. canadensis and C. fiber) as well as fossil specimens of C. fiber (Pleistocene), C. californicus (Pliocene) and the early castorids Steneofiber eseri (early Miocene). The results show that the specimen falls outside the Castor morphospace and that compared to Castor, Sinocastor possesses a: 1) narrower post-orbital constriction, 2) anteroposteriorly shortened basioccipital depression, 3) shortened incisive foramen, 4) more posteriorly located palatine foramen, 5) longer rostrum, and 6) longer braincase. Also the specimen shows a much shallower basiocciptal depression than what is seen in living Castor, as well as prominently rooted molars. We conclude that Sinocastor is a valid genus. Given the prevalence of apparently primitive traits, Sinocastor might be a near relative of the lineage that gave rise to Castor, implying a possible Asiatic origin for Castor

    Sugar and abscisic acid signaling orthologs are activated at the onset of ripening in grape

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    The onset of ripening involves changes in sugar metabolism, softening, and color development. Most understanding of this process arises from work in climacteric fruits where the control of ripening is predominately by ethylene. However, many fruits such as grape are nonclimacteric, where the onset of ripening results from the integration of multiple hormone signals including sugars and abscisic acid (ABA). In this study, we identified ten orthologous gene families in Vitis vinifera containing components of sugar and ABA-signaling pathways elucidated in model systems, including PP2C protein phosphatases, and WRKY and homeobox transcription factors. Gene expression was characterized in control- and deficit-irrigated, field-grown Cabernet Sauvignon. Sixty-seven orthologous genes were identified, and 38 of these were expressed in berries. Of the genes expressed in berries, 68% were differentially expressed across development and/or in response to water deficit. Orthologs of several families were induced at the onset of ripening, and induced earlier and to higher levels in response to water deficit; patterns of expression that correlate with sugar and ABA accumulation during ripening. Similar to field-grown berries, ripening phenomena were induced in immature berries when cultured with sucrose and ABA, as evidenced by changes in color, softening, and gene expression. Finally, exogenous sucrose and ABA regulated key orthologs in culture, similar to their regulation in the field. This study identifies novel candidates in the control of nonclimacteric fruit ripening and demonstrates that grape orthologs of key sugar and ABA-signaling components are regulated by sugar and ABA in fleshy fruit

    Molecular phylogeny and timing of diversification in Alpine Rhithrogena (Ephemeroptera: Heptageniidae).

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    BACKGROUND: Larvae of the Holarctic mayfly genus Rhithrogena Eaton, 1881 (Ephemeroptera, Heptageniidae) are a diverse and abundant member of stream and river communities and are routinely used as bio-indicators of water quality. Rhithrogena is well diversified in the European Alps, with a number of locally endemic species, and several cryptic species have been recently detected. While several informal species groups are morphologically well defined, a lack of reliable characters for species identification considerably hampers their study. Their relationships, origin, timing of speciation and mechanisms promoting their diversification in the Alps are unknown. RESULTS: Here we present a species-level phylogeny of Rhithrogena in Europe using two mitochondrial and three nuclear gene regions. To improve sampling in a genus with many cryptic species, individuals were selected for analysis according to a recent DNA-based taxonomy rather than traditional nomenclature. A coalescent-based species tree and a reconstruction based on a supermatrix approach supported five of the species groups as monophyletic. A molecular clock, mapped on the most resolved phylogeny and calibrated using published mitochondrial evolution rates for insects, suggested an origin of Alpine Rhithrogena in the Oligocene/Miocene boundary. A diversification analysis that included simulation of missing species indicated a constant speciation rate over time, rather than any pronounced periods of rapid speciation. Ancestral state reconstructions provided evidence for downstream diversification in at least two species groups. CONCLUSIONS: Our species-level analyses of five gene regions provide clearer definitions of species groups within European Rhithrogena. A constant speciation rate over time suggests that the paleoclimatic fluctuations, including the Pleistocene glaciations, did not significantly influence the tempo of diversification of Alpine species. A downstream diversification trend in the hybrida and alpestris species groups supports a previously proposed headwater origin hypothesis for aquatic insects

    Uma promenade nos trópicos: os barões do café sob as palmeiras-imperiais, entre o Rio de Janeiro e São Paulo

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    This paper proposes to discuss the transformation of urban landscapes in the Paraíba River Valley as members of the coffee elite emerged in this area and a specific landscape configuration was projected there based on the use of imperial palms (Roystonea oleracea). Chronologically speaking, the paper covers a period from 1808 to 1911; with regard to space, it focuses on the stretch between Rio de Janeiro and São Paulo, with a closer look at the case of the city of Lorena (SP), so as to encompass all the changes that took place in this region from the introduction to the decline of coffee growing as an economic activity. The urban changes during this period were accompanied by the advent and consolidation of landscapes typical of the society of coffee growers: streets lined with palm trees, a token of their close connections with the royal court, a display of their adherence to "Frenchified customs". Such configurations were used to characterize public areas and raise them to the same status as the new buildings that gradually replaced those built in colonial style. The paper is structured around three key moments, namely: the introduction of imperial palms in Rio de Janeiro and their association with the idea of nobility and rank, and consequently with neoclassical architecture, which was brought to the colony by the 1816 French Mission; the dissemination of the use of imperial palms as a landscaping resource typical of public spaces from the royal court to the capital of São Paulo, particularly by the coffee barons during the second period of monarchic rule; and, finally, the hypothesis that the use of imperial palms to embellish public areas in São Paulo may have been introduced by a Lorena citizen associated with the coffee elite, albeit later, when Brazil was already a republic.O presente trabalho propõe-se a discutir a transformação da paisagem urbana das cidades vale-paraibanas, a partir do estabelecimento de uma elite ligada à cultura do café nessa região e do surgimento de uma configuração paisagística específica, apoiada na utilização da palmeira-imperial (Roystonea oleracea). Seu recorte cronológico abrange o período entre 1808 e 1911, enquanto espacialmente seu foco direciona-se para o eixo Rio de Janeiro-São Paulo, com estudo mais aproximado do caso da cidade de Lorena, São Paulo, de modo a cobrir as transformações aí ocorridas desde a chegada do café até o esgotamento dessa cultura. Acompanhando as transformações urbanas do período, surgiram e consolidaram-se exemplos paisagísticos próprios da sociedade do café: ruas arborizadas com renques de palmeiras, a demonstrar a proximidade com a Corte, a sinalizar os novos "modos afrancesados". Utilizaram-se tais configurações com o propósito de qualificar os logradouros públicos, a fim de equipará-los aos novos edifícios que substituíam aqueles da tradição colonial. O texto desenvolve-se em três momentos principais: a introdução da palmeira-imperial no Rio de Janeiro, sua vinculação à idéia de nobreza e classe, e conseqüente aproximação com a arquitetura neoclássica trazida pela Missão Francesa de 1816; a difusão de sua utilização como recurso paisagístico qualificador dos espaços públicos desde a Corte até a capital paulista, principalmente pelo baronato do Segundo Império; e, finalmente, a possibilidade de sua introdução nos espaços públicos paulistanos ter sido viabilizada por um lorenense, vinculado à elite cafeeira, embora já sob a República
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