7 research outputs found

    Unravelling hybridization in Phytophthora using phylogenomics and genome size estimation

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    The genus Phytophthora comprises many economically and ecologically important plant pathogens. Hybrid species have previously been identified in at least six of the 12 phylogenetic clades. These hybrids can potentially infect a wider host range and display enhanced vigour compared to their progenitors. Phytophthora hybrids therefore pose a serious threat to agriculture as well as to natural ecosystems. Early and correct identification of hybrids is therefore essential for adequate plant protection but this is hampered by the limitations of morphological and traditional molecular methods. Identification of hybrids is also important in evolutionary studies as the positioning of hybrids in a phylogenetic tree can lead to suboptimal topologies. To improve the identification of hybrids we have combined genotyping-by-sequencing (GBS) and genome size estimation on a genus-wide collection of 614 Phytophthora isolates. Analyses based on locus- and allele counts and especially on the combination of species-specific loci and genome size estimations allowed us to confirm and characterize 27 previously described hybrid species and discover 16 new hybrid species. Our method was also valuable for species identification at an unprecedented resolution and further allowed correct naming of misidentified isolates. We used both a concatenation- and a coalescent-based phylogenomic method to construct a reliable phylogeny using the GBS data of 140 non-hybrid Phytophthora isolates. Hybrid species were subsequently connected to their progenitors in this phylogenetic tree. In this study we demonstrate the application of two validated techniques (GBS and flow cytometry) for relatively low cost but high resolution identification of hybrids and their phylogenetic relations.info:eu-repo/semantics/publishedVersio

    Utilization of plant secondary metabolites for plant protection

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    AbstractIn the past two decades, the need for a new concept in agriculture has emerged. The new “Greener revolution” should rely on the implementation of sustainable practices in crop production and the achievement of increased yields under the conditions of reduction of water, fertilizer, and pesticide use. The utilization of plant secondary metabolites is viewed by many authors as а possible alternative to synthetic chemicals. Bioactive botanical compounds can be obtained from plants in the form of extracts, essential oils (EO), or both. There are four main groups of plant secondary metabolites depending on their chemical structure: terpenes, phenolics, nitrogen-, and sulfur-containing compounds. A growing body of publications is devoted to the pesticidal properties of various secondary metabolites obtained from plants. The botanical families Meliaceae, Rutaceae, Asteraceae, Annonaceae, Labiatae, and Canellaceae include the most valuable species that are rich in secondary metabolites. The strong fumigant properties of the EOs from many plant species make them attractive in different Integrated Post-Harvest Pest Management systems. Suitable carriers for EOs delivery can be designed using nanoencapsulation. On a worldwide scale, the main botanical insecticides that are commercially available at present are Pyrethrum, Azadirachtin from Neem, and EOs from various plant species. Among the botanicals with considerable antimicrobial activity, there are some successfully authorized and developed commercial phenolics, terpenes, and alkaloids. Among the proven active substances are cinnamaldehyde, l-glutamic acid and gamma-aminobutyric acid, Jojoba oil, еssential oils, and others

    Plant extracts and Trichoderma spp: possibilities for implementation in agriculture as biopesticides

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    AbstractThe overuse of agrochemicals and development of pesticide resistance in plant pathogens is a main challenge in conventional agriculture. The use of biopesticides based on natural substances is recognized as an effective alternative of conventional pesticides. Besides the beneficial microorganisms, some plant species can be a source of microbiologically active compounds. Among the most promising are Origanum vulgare ssp. hirtum, Centaurea finazzeri, Achillea crithmifolia, Artemisia spp, Thymus pulegioides, Tanacetum parthenium, Clinopodium vulgare, Salvia sclarea, Lavandula officinalis and Mentha piperita. The filamentous fungi from genus Trichoderma are some of the most studied biocontrol agents because of their versatile mode of action. They employ several different strategies to combat plant pathogens, like direct mycoparasitism, production of enzymes and antibiotic substances, competition, ability to induce resistance in plants to a variety of stresses. Cost-effective cultivation and mass production of Trichoderma sp. biomass and formulations will allow utilization of locally available low-cost materials, such as different wastes and by-products that could be used as a growth substrate for production of adequate biomass containing effective propagules with or without minimal adjustments to the composition of cultivation media. This review outlines the two major mass production methods - solid and liquid state fermentation of Trichoderma spp. The possibilities for development of novel products for the bioindustry are highlighted

    Data from: Unravelling hybridization in Phytophthora using phylogenomics and genome size estimation

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    The genus Phytophthora comprises many economically and ecologically important plant pathogens. Hybrid species have previously been identified in at least six of the 12 phylogenetic clades. These hybrids can potentially infect a wider host range and display enhanced vigour compared to their progenitors. Phytophthora hybrids therefore pose a serious threat to agriculture as well as to natural ecosystems. Early and correct identification of hybrids is therefore essential for adequate plant protection but this is hampered by the limitations of morphological and traditional molecular methods. Identification of hybrids is also important in evolutionary studies as the positioning of hybrids in a phylogenetic tree can lead to suboptimal topologies. To improve the identification of hybrids we have combined genotyping-by-sequencing (GBS) and genome size estimation on a genus-wide collection of 614 Phytophthora isolates. Analyses based on locus- and allele counts and especially on the combination of species-specific loci and genome size estimations allowed us to confirm and characterize 27 previously described hybrid species and discover 16 new hybrid species. Our method was also valuable for species identification at an unprecedented resolution and further allowed correct naming of misidentified isolates. We used both a concatenation- and a coalescent-based phylogenomic method to construct a reliable phylogeny using the GBS data of 140 non-hybrid Phytophthora isolates. Hybrid species were subsequently connected to their progenitors in this phylogenetic tree. In this study we demonstrate the application of two validated techniques (GBS and flow cytometry) for relatively low cost but high resolution identification of hybrids and their phylogenetic relations

    From leaf to continent: The multi-scale distribution of an invasive cryptic pathogen complex on oak

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    The spatial distribution and niche differentiation of three closely related species (Erysiphe alphitoides, Erysiphe quercicola and Erysiphe hypophylla) causing oak powdery mildew was studied at scales ranging from the European continent, where they are invasive, to a single leaf. While E. alphitoides was dominant at all scales, E. quercicola and E. hypophylla had restricted geographic, stand and leaf distributions. The large-scale distributions were likely explained by climatic factors and species environmental tolerances, with E. quercicola being more frequent in warmer climates and E. hypophylla in colder climates. The extensive sampling and molecular analyses revealed the cryptic invasion of E. quercicola in nine countries from which it had not previously been recorded. The presence of the three species was also strongly affected by host factors, such as oak species and developmental stage. Segregation patterns between Erysiphe species were observed at the leaf scale, between and within leaf surfaces, suggesting competitive effects
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