Transgenic potato plants have been produced that express and secrete the foreign bacteriophage T4... more Transgenic potato plants have been produced that express and secrete the foreign bacteriophage T4 lysozyme. The chimeric barley a-amylase signal peptide — T4 lysozyme gene is driven by the CaMV 35S promoter. Low level expression can be detected at mRNA and protein level. Subcellular localization analysis demonstrates secretion of the foreign protein to the intercellular spaces. Biological in vitro and greenhouse experiments demonstrate that tuber maceration following inoculation with Erwinia carotovora atroseptica in transgenic tissue is significantly reduced in comparison to control tissues. Moreover, explants from inoculated transgenic tuber pieces show sprouting and growth without development of disease symptoms. Expression and secretion of the foreign lysozyme obviously leads to a reduced susceptibility of the transgenic potato plants towards the phytopathogenic bacterium.
First publications of successful Agrobacterium-mediated transformation of tobacco were published ... more First publications of successful Agrobacterium-mediated transformation of tobacco were published more than 30 years ago. Protocols for Agrobacterium-based transformation as well as biolistic bombardment and PEG transformation of protoplasts are available for more than 150 plant species from various plant families. Also for many Populus species and hybrids, adapted transformation protocols have been published. The standard protocol for Agrobacterium-mediated transformation of different Populus genotypes is the leaf-disc method. Here, we first describe the transfer of genes into poplar by using the Agrobacterium-based leaf disc methods. In addition, alternative basic transformation methods, namely, biolistic bombardment and PEG transformation of protoplasts, are also described. Further, we present improved poplar transformation protocols by simplifying the transformation procedure and optimizing tissue preparation and plant regeneration.
Embryogenesis and plant regeneration have been obtained from isolated immature pollen of two popl... more Embryogenesis and plant regeneration have been obtained from isolated immature pollen of two poplar hybrids (Populus nigra L. x hybrid 'Aue1' and 'Aue2'). In total, 1487 calli or embryos, respectively, larger than 1 mm were generated in a 2-year study. By using a cytokinin containing induction medium, on average 19 calli per responsive immature catkin were formed. Additional supplementation with auxin in 2002 increased the frequency to 72 calli per catkin. Microsatellite marker analyses confirmed haploid origin in most regenerants studied. So far six out of eight obtained regenerative callus lines have maintained their haploid level up to 24 months of development. A number of haploid and doubled haploid plants of different lines are available and have been transferred to soil.
A progeny of 130 F1individuals of an interspecific cross between Populus tremula L. and Populus t... more A progeny of 130 F1individuals of an interspecific cross between Populus tremula L. and Populus tremuloides Michx. was used for genetic mapping of linkage group XIX with SSR markers based on the Populus trichocarpa Torr. & A. Gray genome sequence. Several fully sex-linked SSR markers were identified and mapped to a central position on the male P. tremuloides map of linkage group XIX. For the SSR markers tested here, the position on the assembled P. trichocarpa genome sequence is known, allowing sex-linked markers to be assigned to the central region of scaffold/chromosome 19 of P. trichocarpa. The sex linkage of the SSR markers was validated in other P. tremula × P. tremuloides crosses and also tested in Populus alba L. and Populus nigra L.
AFZ, der Wald: allgemeine Forstzeitschrift für Waldwirtschaft und Umweltvorsorge, 2012
Diverse Pappelarten, -hybride und -klone konnen inzwischen anhand von molekularen Markern identif... more Diverse Pappelarten, -hybride und -klone konnen inzwischen anhand von molekularen Markern identifiziert und voneinander unterschieden werden. Pappeln aus verschiedenen Klonsammlungen und Mutterquartieren wurden mithilfe dieser Marker auf ihre Identitat mit dem Ergebnis uberpruft, dass einige Pappelhybride und Klone nicht das sind, was sie laut Etikettierung sein sollten. Jahrzehnte zuchterischer Arbeit haben hier ihre Spuren hinterlassen. Die eingeschlichenen Fehler konnen jetzt mithilfe der molekularen Marker aufgedeckt und korrigiert werden
Plants harbour a wide range of leaf‐feeding insects whose survival and fitness are influenced by ... more Plants harbour a wide range of leaf‐feeding insects whose survival and fitness are influenced by both energy‐rich molecules and phytochemicals in the host foliage. Yet, how leaf host chemical diversity and insect microbiota—key factors in ecological and physiological processes—impact insect nutrition and fitness are still poorly understood. To study the effects of leaf metabolic composition on insect herbivory resistance and performance, we fed the larvae of the specialist herbivory Tortrix viridana with leaves of susceptible and resistant Quercus robur trees that are characterized by contrasting metabolomes. We analysed the larval performance and mortality, the metabolomes in plant leaves, and in the insects' saliva and faeces by non‐targeted metabolomics. Using chemometrics, mass difference network analysis and metabarcoding, we show the metabolome changes and chemical reactions associated with the different diets as well as their impact on insect fitness and gut microbiota. In the saliva and faeces of larvae, plant secondary metabolites (e.g. flavonoids) persisted more the insect digestion while compounds from primary metabolism were more depleted. In addition, metabolic reactions within the larvae indicated different degradation pathways used on the two plant metabolic types (syn. metabotypes), including sulfation and sulfonation. We show that feeding insects with resistant oak leaves, enriched in secondary metabolites and depleted in primary metabolites, impaired insect performance and mortality. Although the insects' gut microbiota was slightly different upon the contrasting diets, overall, it was fairly stable. Despite the impact of host chemicals on herbivores, larvae were generally highly efficient in nutrient assimilation (feed conversion ratios of 3.3–3.6) and able to minimize plant defences (78% of secondary metabolites were converted, broken down or sequestrated). The comparison of the oak metabotypes showed how the foliar composition of resistant oaks affected insect fitness by influencing their digestion. Herbivores feeding on resistant oaks were less efficient due to their lower ability to metabolize and detoxify higher levels of host phytochemicals, whereas those on susceptible oaks were more efficient as they could degrade the host metabolome. This study highlights the importance of the oak leaf chemical composition to insect digestion and fitness of a specialized herbivore. Read the free Plain Language Summary for this article on the Journal blog.
AFZ, der Wald: allgemeine Forstzeitschrift für Waldwirtschaft und Umweltvorsorge, 2019
Pfl anzenschadlinge und eingeschleppte Krankheiten stellen eine wachsende Bedrohung fur die Stabi... more Pfl anzenschadlinge und eingeschleppte Krankheiten stellen eine wachsende Bedrohung fur die Stabilitat von heimischen Waldokosystemen dar. Die klassische Forstpfl anzenzuchtung verfugt aber nur uber eingeschrankte Mittel, sich kurzfristig diesen Herausforderungen zu stellen, da meistens die dafur erforderlichen resistenten Baume fehlen. Die Forderung von Resistenzen durch erworbene individuelle Immunitat („Pragung“) hat ein groses Potenzial fur die Rettung bedrohter Baumarten.
Transgenic potato plants have been produced that express and secrete the foreign bacteriophage T4... more Transgenic potato plants have been produced that express and secrete the foreign bacteriophage T4 lysozyme. The chimeric barley a-amylase signal peptide — T4 lysozyme gene is driven by the CaMV 35S promoter. Low level expression can be detected at mRNA and protein level. Subcellular localization analysis demonstrates secretion of the foreign protein to the intercellular spaces. Biological in vitro and greenhouse experiments demonstrate that tuber maceration following inoculation with Erwinia carotovora atroseptica in transgenic tissue is significantly reduced in comparison to control tissues. Moreover, explants from inoculated transgenic tuber pieces show sprouting and growth without development of disease symptoms. Expression and secretion of the foreign lysozyme obviously leads to a reduced susceptibility of the transgenic potato plants towards the phytopathogenic bacterium.
First publications of successful Agrobacterium-mediated transformation of tobacco were published ... more First publications of successful Agrobacterium-mediated transformation of tobacco were published more than 30 years ago. Protocols for Agrobacterium-based transformation as well as biolistic bombardment and PEG transformation of protoplasts are available for more than 150 plant species from various plant families. Also for many Populus species and hybrids, adapted transformation protocols have been published. The standard protocol for Agrobacterium-mediated transformation of different Populus genotypes is the leaf-disc method. Here, we first describe the transfer of genes into poplar by using the Agrobacterium-based leaf disc methods. In addition, alternative basic transformation methods, namely, biolistic bombardment and PEG transformation of protoplasts, are also described. Further, we present improved poplar transformation protocols by simplifying the transformation procedure and optimizing tissue preparation and plant regeneration.
Embryogenesis and plant regeneration have been obtained from isolated immature pollen of two popl... more Embryogenesis and plant regeneration have been obtained from isolated immature pollen of two poplar hybrids (Populus nigra L. x hybrid 'Aue1' and 'Aue2'). In total, 1487 calli or embryos, respectively, larger than 1 mm were generated in a 2-year study. By using a cytokinin containing induction medium, on average 19 calli per responsive immature catkin were formed. Additional supplementation with auxin in 2002 increased the frequency to 72 calli per catkin. Microsatellite marker analyses confirmed haploid origin in most regenerants studied. So far six out of eight obtained regenerative callus lines have maintained their haploid level up to 24 months of development. A number of haploid and doubled haploid plants of different lines are available and have been transferred to soil.
A progeny of 130 F1individuals of an interspecific cross between Populus tremula L. and Populus t... more A progeny of 130 F1individuals of an interspecific cross between Populus tremula L. and Populus tremuloides Michx. was used for genetic mapping of linkage group XIX with SSR markers based on the Populus trichocarpa Torr. & A. Gray genome sequence. Several fully sex-linked SSR markers were identified and mapped to a central position on the male P. tremuloides map of linkage group XIX. For the SSR markers tested here, the position on the assembled P. trichocarpa genome sequence is known, allowing sex-linked markers to be assigned to the central region of scaffold/chromosome 19 of P. trichocarpa. The sex linkage of the SSR markers was validated in other P. tremula × P. tremuloides crosses and also tested in Populus alba L. and Populus nigra L.
AFZ, der Wald: allgemeine Forstzeitschrift für Waldwirtschaft und Umweltvorsorge, 2012
Diverse Pappelarten, -hybride und -klone konnen inzwischen anhand von molekularen Markern identif... more Diverse Pappelarten, -hybride und -klone konnen inzwischen anhand von molekularen Markern identifiziert und voneinander unterschieden werden. Pappeln aus verschiedenen Klonsammlungen und Mutterquartieren wurden mithilfe dieser Marker auf ihre Identitat mit dem Ergebnis uberpruft, dass einige Pappelhybride und Klone nicht das sind, was sie laut Etikettierung sein sollten. Jahrzehnte zuchterischer Arbeit haben hier ihre Spuren hinterlassen. Die eingeschlichenen Fehler konnen jetzt mithilfe der molekularen Marker aufgedeckt und korrigiert werden
Plants harbour a wide range of leaf‐feeding insects whose survival and fitness are influenced by ... more Plants harbour a wide range of leaf‐feeding insects whose survival and fitness are influenced by both energy‐rich molecules and phytochemicals in the host foliage. Yet, how leaf host chemical diversity and insect microbiota—key factors in ecological and physiological processes—impact insect nutrition and fitness are still poorly understood. To study the effects of leaf metabolic composition on insect herbivory resistance and performance, we fed the larvae of the specialist herbivory Tortrix viridana with leaves of susceptible and resistant Quercus robur trees that are characterized by contrasting metabolomes. We analysed the larval performance and mortality, the metabolomes in plant leaves, and in the insects' saliva and faeces by non‐targeted metabolomics. Using chemometrics, mass difference network analysis and metabarcoding, we show the metabolome changes and chemical reactions associated with the different diets as well as their impact on insect fitness and gut microbiota. In the saliva and faeces of larvae, plant secondary metabolites (e.g. flavonoids) persisted more the insect digestion while compounds from primary metabolism were more depleted. In addition, metabolic reactions within the larvae indicated different degradation pathways used on the two plant metabolic types (syn. metabotypes), including sulfation and sulfonation. We show that feeding insects with resistant oak leaves, enriched in secondary metabolites and depleted in primary metabolites, impaired insect performance and mortality. Although the insects' gut microbiota was slightly different upon the contrasting diets, overall, it was fairly stable. Despite the impact of host chemicals on herbivores, larvae were generally highly efficient in nutrient assimilation (feed conversion ratios of 3.3–3.6) and able to minimize plant defences (78% of secondary metabolites were converted, broken down or sequestrated). The comparison of the oak metabotypes showed how the foliar composition of resistant oaks affected insect fitness by influencing their digestion. Herbivores feeding on resistant oaks were less efficient due to their lower ability to metabolize and detoxify higher levels of host phytochemicals, whereas those on susceptible oaks were more efficient as they could degrade the host metabolome. This study highlights the importance of the oak leaf chemical composition to insect digestion and fitness of a specialized herbivore. Read the free Plain Language Summary for this article on the Journal blog.
AFZ, der Wald: allgemeine Forstzeitschrift für Waldwirtschaft und Umweltvorsorge, 2019
Pfl anzenschadlinge und eingeschleppte Krankheiten stellen eine wachsende Bedrohung fur die Stabi... more Pfl anzenschadlinge und eingeschleppte Krankheiten stellen eine wachsende Bedrohung fur die Stabilitat von heimischen Waldokosystemen dar. Die klassische Forstpfl anzenzuchtung verfugt aber nur uber eingeschrankte Mittel, sich kurzfristig diesen Herausforderungen zu stellen, da meistens die dafur erforderlichen resistenten Baume fehlen. Die Forderung von Resistenzen durch erworbene individuelle Immunitat („Pragung“) hat ein groses Potenzial fur die Rettung bedrohter Baumarten.
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