371 research outputs found

    Systemic fungal endophytes and ploidy level in Festuca vivipara populations in North European Islands

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    Exploring the regional pattern of variation in traits driven by symbiotic interactions may provide insights to understand the evolutionary processes that operate over plant populations. Polyploidy, which is associated with fitness improvement, is expected to increase with latitude and altitude. However, it has never been explored in relation with the occurrence of epichloid fungal endophytes in plants. Both, variation in ploidy level and in the incidence of fungal endophytes, are known to occur in species of fine fescues. Here, we surveyed the occurrence of systemic fungal endophytes in natural Festuca vivipara populations in North European islands. In addition, we identified the fungal species associated with this grass and determined the predominant ploidy level for each population. Endophytes were found in four of six, two of three, and one of three populations for Faroe Islands, Iceland and Great Britain, respectively. With an average low incidence level of 15 % in infected populations, there was no relationship between infection level and either latitude or altitude. The phylogenetic analysis based on sequences ITS and the tub2 genes, supports that the endophytic species is EpichloA &lt;&lt; festucae, the same as in other fine fescues. We found no variation in ploidy level as all the plants were tetraploid (4X) with 28 chromosomes, a pattern which contrasts with the variation reported in previous antecedents. Our results suggest that apart from low and variable benefits of the endophyte to the plants, there would be a complex dynamics between epichloid endophytes and species of the fine fescue complex which merits further studies.</p

    Fast Indexes for Gapped Pattern Matching

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    We describe indexes for searching large data sets for variable-length-gapped (VLG) patterns. VLG patterns are composed of two or more subpatterns, between each adjacent pair of which is a gap-constraint specifying upper and lower bounds on the distance allowed between subpatterns. VLG patterns have numerous applications in computational biology (motif search), information retrieval (e.g., for language models, snippet generation, machine translation) and capture a useful subclass of the regular expressions commonly used in practice for searching source code. Our best approach provides search speeds several times faster than prior art across a broad range of patterns and texts.Comment: This research is supported by Academy of Finland through grant 319454 and has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Actions H2020-MSCA-RISE-2015 BIRDS GA No. 69094

    Data on litter quality of host grass plants with and without fungal endophytes

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    Certain Pooideae species form persistent symbiosis with fungal endophytes of Epichloë genus. Although endophytes are known to impact the ecology and evolution of host species, their effects on parameters related with quality of plant biomass has been elusive. This article provides information about parameters related with the quality of plant litter biomass of two important grass species (Schedonorus phoenix and Schedonorus pratensis) affected by the symbiosis with fungal endophytes (Epichloë coenophiala and Epichloë uncinata, respectively). Four population origins of S. phoenix and one of S. pratensis were included. Mineral, biochemical and structural parameters were obtained from three samples per factors combination [species (and population origin)×endophyte]. This data can be potentially used in other studies which, by means of 'data reanalyzing' or meta-analysis, attempt to find generalizations about endophyte effects on host plant litter biomass. The present data is associated with the research article "Role of foliar fungal endophytes on litter decomposition among species and population origins" (Gundel et al., In preparation) [1]

    Do dividends signal future earnings in the Nordic stock markets?

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    We study the informational content of dividends on three Nordic civil law markets, where other simultaneous but blurring motives for dividends may be weaker. Using aggregate data on real earnings per share and payout ratios, long time series from 1969 to 2010, and methodologies which address problems of endogeneity, non-stationarity and autocorrelation (including a Vector Error Correction Model approach), we find evidence on dividend signaling in Nordic markets. However, we also find heterogeneity in the relationship between dividends and earnings on markets similar in many respects, suggesting that even small variations in the institutional surroundings may be important for the results
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