Cumulative individual seed production in the polycarpic Caesalpinia gilliesii (Fabaceae): effects of temporal variability in floral display, plant density and pollination

In polycarpic species, floral display size and density of conspecific neighbours are time variable as well as their effects on pollination and fecundity. Here, we address how individual pollinator-dependent seed production responds to changes in floral display size and the density of flowering conspecific neighbours. Using path analysis, we disentangle the partial effects of floral display size, the density of flowering neighbours and pollination intensity on the total seed output of the partially self-compatible shrub Caesalpinia gilliesii during three consecutive reproductive seasons. We also modelled the effects of temporal variability in floral offer and pollination intensity (as the coefficient of variation) on cumulative seed production over the study period. Floral display size had either positive or negative effects on pollination intensity in different reproductive seasons, but conspecific density had no significant effect within each season. However, cumulative seed production increased under lower temporal variability in conspecific density. Our results suggest that, because of the dynamic nature of floral offer in a polycarpic species, the temporal changes in floral display size and density may counteract each other reducing the risk of successive pollination failures and increasing seed production over time.Fil: Calviño, Ana Alejandra. 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: Ashworth, Lorena. 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: Galetto, Leonardo. 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; Argentin

Loss of YABBY2-Like Gene Expression May Underlie the Evolution of the Laminar Style in Canna and Contribute to Floral Morphological Diversity in the Zingiberales.

The Zingiberales is an order of tropical monocots that exhibits diverse floral morphologies. The evolution of petaloid, laminar stamens, staminodes, and styles contributes to this diversity. The laminar style is a derived trait in the family Cannaceae and plays an important role in pollination as its surface is used for secondary pollen presentation. Previous work in the Zingiberales has implicated YABBY2-like genes, which function in promoting laminar outgrowth, in the evolution of stamen morphology. Here, we investigate the evolution and expression of Zingiberales YABBY2-like genes in order to understand the evolution of the laminar style in Canna. Phylogenetic analyses show that multiple duplication events have occurred in this gene lineage prior to the diversification of the Zingiberales. Reverse transcription-PCR in Canna, Costus, and Musa reveals differential expression across floral organs, taxa, and gene copies, and a role for YABBY2-like genes in the evolution of the laminar style is proposed. Selection tests indicate that almost all sites in conserved domains are under purifying selection, consistent with their functional relevance, and a motif unique to monocot YABBY2-like genes is identified. These results contribute to our understanding of the molecular mechanisms underlying the evolution of floral morphologies

Specialisation in pollen collection, pollination interactions and phenotypic variation of the oil-collecting bee Chalepogenus cocuccii

Bee pollen gathering from a few related plant species is a specialisation known as oligolecty. Although it is an extended phenomenon, it has been scarcely explored in oil-collecting bees. At the geographic level, there is little information about oligolecty persistence and also about phenotypic variation of bees related with abiotic factors. We studied the pollen collection specialisation of the oil-collecting bee Chalepogenus cocuccii, its pollination interactions and phenotypic variation across its distribution range, by analyses of pollen loads, field observations and morphometric measurements. Observations and pollen analyses showed that across its distribution range, C. cocuccii preferred Nierembergia flowers not only for oil but also for pollen. We found two bee-morphotypes, though phenotypic variation was not related to abiotic variables. We postulate that C. cocuccii is a narrowly oligolectic species, phenotypically and ecologically specialised in Nierembergia.Fil: Maubecin, Constanza Clara. 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: Boero, María Lourdes. 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: Sersic, Alicia Noemi. 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; Argentin

Biología de especies australes: Opuntia quimilo K. Schum.

Opuntia quimilo K. Schum. pertenece a la familia Cactaceae Juss. Esta familia, presenta una distribución geográfica restringida al continente Americano, a excepción de Rhipsalis baccifera (J.S. Muell.) Stearn, que vive en Sri Lanka, África tropical, Madagascar, islas Comores, Seychelles y Mascarenes, y se considera dudosamente nativa de estas zonas (Anderson, 2001). La familia cuenta con aproximadamente 93 géneros y 1400 especies y su principal centro de diversificación es México (Judd et al., 2002; Guzman et al., 2003). El género Opuntia Mill. se encuentra incluido dentro de la subfamilia Opuntioideae, presenta 19 géneros y 350 especies ampliamente diversificada en formas y hábitats que ocupan (Hunt et al., 2006). Según estudios filogenéticos recientes, el origen de esta subfamilia se postula para el centro oeste de Sudamérica (Griffith & Portert, 2009). Opuntia, con 191 especies, es el género más numeroso dentro de la familia (Anderson, 2001). Se halla naturalizado en Australia y Sudáfrica y se encuentra distribuido desde el nivel del mar y hasta los 4700 m de altura en los andes del Perú (Nobel, 1988). Los géneros de Opuntia más afines filogenéticamente son Tacinga Britton & Rose y Brasiliopuntia A. Berger (Griffith & Portert, 2009). La etimología del nombre Opuntia hace referencia a Opus, cuidad de Grecia donde se supone que crecían plantas cactiformes; quimilo: hace referencia a su nombre vulgar (Sérsic et al., 2007). Opuntia quimilo es conocida vulgarmente como «quimilo», «quimil» y «quimilí» (Trevisson & Demaio, 2006).Fil: Nattero, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad Nacional de Córdoba. Facultad de Cs.exactas Físicas y Naturales. Departamento de Fisiología. Cátedra de Introducción A la Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Malerba, Romina Celeste. Universidad Nacional de Córdoba. Facultad de Cs.exactas Físicas y Naturales. Departamento de Fisiología. Cátedra de Introducción A la Biología; Argentin

Dynamin recruitment and membrane scission at the neck of a clathrin-coated pit

Dynamin, the GTPase required for clathrin-mediated endocytosis, is recruited to clathrin-coated pits in two sequential phases. The first is associated with coated pit maturation; the second, with fission of the membrane neck of a coated pit. Using gene-edited cells that express dynamin2-EGFP instead of dynamin2 and live-cell TIRF imaging with single-molecule EGFP sensitivity and high temporal resolution, we detected the arrival of dynamin at coated pits and defined dynamin dimers as the preferred assembly unit. We also used live-cell spinning-disk confocal microscopy calibrated by single-molecule EGFP detection to determine the number of dynamins recruited to the coated pits. A large fraction of budding coated pits recruit between 26 and 40 dynamins (between 1 and 1.5 helical turns of a dynamin collar) during the recruitment phase associated with neck fission; 26 are enough for coated vesicle release in cells partially depleted of dynamin by RNA interference. We discuss how these results restrict models for the mechanism of dynamin-mediated membrane scission

Biparental inbreeding depression, genetic relatedness and progeny vigor in a wind-pollinated treeline species in Argentina

Spatially restricted gene flow and resulting spatial genetic structure are generally considered as being the primary controlling factors in the dynamics of biparental inbreeding depression in a wide range of plant species. However, wind-pollinated angiosperm trees have not been adequately studied in this respect. The present study analyses the relationships between parental genetic similarity, outcrossing distances and progeny vigour in Polylepis australis (Rosaceae), a wind-pollinated treeline species endemic to Argentina. We investigated whether spatial genetic structuring occurs in anthropogenically fragmented P. australis woodlands of the Córdoba Mountains. We also performed a controlled crossing experiment using pollen collected from different distances. Genetic variability (using RAPD-PCR) and vigour (survival and N metabolism capacity) of the resulting progeny were contrasted with progeny from unmanipulated flowers. We found a continuous decrease in parental genetic similarity with spatial distance among mates and an increase in genetic variability, survival and N metabolism capacity in the progeny produced from pollen at increasing distances. However, our further results suggest fragment connectivity in P. australis through effective long-distance pollen-mediated gene flow with no effective inbreeding depression problems observed under present day conditions.Fil: Seltmann, Peggy. Martin-Luther-University Halle-Wittenberg; AlemaniaFil: Hensen, Isabell. Martin-Luther-University Halle-Wittenberg; AlemaniaFil: Renison, Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Wesche, Karsten. University of Göttingen; AlemaniaFil: Ploch, Sebastián. University of Hohenheim; AlemaniaFil: Rondan Dueñas, Juan. Universidad Nacional de Córdoba; ArgentinaFil: Cocucci, Andrea Aristides. 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: Jung, Klaus. Helmholtz Centre for Environmental Research-UFZ; Alemani

The importance of oligosulfides in the attraction of fly pollinators to the brood-site deceptive species Jaborosa rotacea (Solanaceae).

Premise of research. Brood-site deceptive flowers use dishonest signals?especially floral odors that mimic oviposition substrates?to attract and deceive saprophilous insects to pollinate them. In this work, we recorded the pollinators of the sapromyiophilous species Jaborosa rotacea (Solanaceae) endemic to southern South America. Then, we characterized the floral volatiles of this species, and finally, we carried out field experiments to decouple the effects of scent and color as attractants for saprophilous flies. Methodology. We made direct observations of pollinators in a natural population of J. rotacea.We characterized floral volatiles by means of gas chromatography?mass spectrometry. Subsequently, we used a mixture of 2 oligosulfides (dimethyl disulfide and dimethyl trisulfide), which our analyses revealed were the main constituents of the floral scent ofJ. rotacea, as baits to determine the attractiveness of this olfactory signal to flies in a geographical region whereJ. rotaceais not present. Finally, we used the same foul-scented baits in arrays of artificial flowers resembling those of J. rotacea to assess the dual importance of olfactory and visual cues in fly attraction. Pivotal results. Pollination of J. rotaceaoccurs when saprophilous flies belonging to the families Calliphoridae, Muscidae, and Sarcophagidae?with similar body dimensions to the anther-stigma distance in these flowers?acquire and deposit pollen in the flowers in a nototribic mode. Our chemical analyses revealed that J. rotacea floral scent is chemically simple and features 2 oligosulfide compounds (dimethyl disulfide and dimethyl trisulfide) commonly found in carrion-mimicking flowers. We found that saprophilous flies belonging to the same families that we recorded as pollinators of J. rotaceain its native South American habitat were attracted to foul-scented baits in temperate North America. The flies? visitation frequencies (recorded as approaches and landings on the artificial flowers) depended significantly on the presence of the foul-scented baits. Conclusions. These results support the hypothesis that oligosulfides are universally effective signals by which deceptive flowers may effect pollen dispersal by attracting flies that use carrion or carnivore feces as brood sites. Keywords:brood-site deceptive flowers, Diptera, Jaborosa rotacea, oligosulfides, scent mimicry, Solanaceae.Fil: More, Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina;Fil: Cocucci, Andrea Aristides. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina;Fil: Raguso, Robert A.. Cornell University; Estados Unidos de América

Actin and dynamin2 dynamics and interplay during clathrin-mediated endocytosis.

Clathrin-mediated endocytosis (CME) involves the recruitment of numerous proteins to sites on the plasma membrane with prescribed timing to mediate specific stages of the process. However, how choreographed recruitment and function of specific proteins during CME is achieved remains unclear. Using genome editing to express fluorescent fusion proteins at native levels and live-cell imaging with single-molecule sensitivity, we explored dynamin2 stoichiometry, dynamics, and functional interdependency with actin. Our quantitative analyses revealed heterogeneity in the timing of the early phase of CME, with transient recruitment of 2-4 molecules of dynamin2. In contrast, considerable regularity characterized the final 20 s of CME, during which ∼26 molecules of dynamin2, sufficient to make one ring around the vesicle neck, were typically recruited. Actin assembly generally preceded dynamin2 recruitment during the late phases of CME, and promoted dynamin recruitment. Collectively, our results demonstrate precise temporal and quantitative regulation of the dynamin2 recruitment influenced by actin polymerization

Comparative anatomy of elaiophores and oil secretion in the genus Gomesa (Orchidaceae)

Oils are atypical floral rewards in Orchidaceae, and are produced by epidermal glands called elaiophores. Flowers of many members of the sub-tribe Oncidiinae either produce oil or mimic oil-producing flowers of Malpighiaceae. We focus our research on three species of Gomesa, namely, G. flexuosa, G. riograndensis and G. varicosa in order to investigate the presence of elaiophores, their micromorphology and internal structure and the process of oil secretion. Elaiophores were located using Sudan III, and their internal and external features examined using light and scanning electron microscopy, respectively. The presence of elaiophores was confirmed for regions of calli that are prominent and exposed. In all three species, the secretory tissue comprised a single layer of epidermal cells, together with some parenchymatous, subsecretory cells. Epidermal cells were isodiametric or palisade-like, with dense cytoplasm, small vacuoles and prominent nuclei. Gomesa flexuosa differs from the other species investigated in that it bears intermediate elaiophores (i.e. epithelial and possessing unicellular, secretory trichomes). Based on the absence of a distended cuticle, we propose that oil possibly passes through the wall and cuticle as small lipid moieties. In addition, some evolutionary trends in the elaiophores in the genus Gomesa are suggested.Fil: Gomiz, Natalia Elva. Universidad de Buenos Aires. Facultad de Agronomia; ArgentinaFil: Torretta, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion; ArgentinaFil: Aliscioni, Sandra Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion; Argentin