The biotrophic fungus Ustilago maydis infects corn and induces the formation of tumors. In order for the fungus to proliferate in the infected tissue, U. maydis has to redirect the metabolism of the host to the site of infection. We wish to elucidate how this is accomplished. To this end we will perform transcript profiling during the time course of infection for both, the fungus and the maize plant. This will be complemented by metabolome analysis of different tissues during infection as well as by apoplastic fluid analysis. The goals will be to identify the carbon sources taken up by the fungus during biotrophic growth, to identify the transporters required for uptake, determine their specificity and elucidate how these carbon sources are provided by the plant. Fungal mutants affected in discrete stages of pathogenic development will be included in these studies. Likely candidate genes for carbon uptake/supply as well as for redirecting host metabolism will be functionally characterized by generating knockouts in the fungus and by isolating plants carrying mutations in respective genes or by generating transgenic plants expressing RNAi constructs.
This project is aimed at the characterization of the systemic reprogramming in barley, which modulates the compatible interaction with the biotrophic leaf pathogen Blumeria graminis f.sp. hordei upon root infestation with the mutualistic endophyte Piriformospora indica. We have recently shown that the basidiomycete P. indica - upon successful establishment in the roots - reprograms barley to salt stress tolerance, resistance to root diseases and higher yield (Waller et al., 2005). Successful powdery mildew infections in barley leaves are also disturbed by the mutualistic fungus. These processes are associated with a strong change in plant metabolism, especially with a drastic alteration of leaf and root antioxidants. On the basis of these findings we will perform an in-depth analysis of the barley metabolome (B6) and transcriptome (B7) with two specific foci: First, to elucidate the process of establishment of the mutualistic fungus within the barley roots; second, to characterize elements of the systemic response in leaves leading to an interruption or failure of compatibility processes required for successful establishment of biotrophic leaf pathogens like Blumeria. New gene candidates will be pre-selected systematically for their regulatory role in compatibility by means of transiently transformed barley leaves upon Blumeria inoculation. Stable transgenic barley and maize lines (B3) generated with verified gene candidates and genes identified by other projects (A1, A2, B5, B6) will be tested with Blumeria and P. indica. By comparing candidate genes in the different plant - microbe systems, we will identify common regulatory processes, metabolites and metabolic networks implicated in compatibility including those required for successful interactions with mutualistic fungi.
SUNBIOPATH - towards a better sunlight to biomass conversion efficiency in microalgae - is an integrated program of research aimed at improving biomass yields and valorisation of biomass for two Chlorophycean photosynthetic microalgae, Chlamydomonas reinhardtii and Dunaliella salina. Biomass yields will be improved at the level of primary processes that occur in the chloroplasts (photochemistry and sunlight capture by the light harvesting complexes) and in the cell (biochemical pathways and signalling mechanisms that influence ATP synthesis). Optimal growth of the engineered microalgae will be determined in photobioreactors, and biomass yields will be tested using a scale up approach in photobioreactors of different sizes (up to 250 L), some of which being designed and built during SUNBIOPATH. Biomethane production will be evaluated. Compared to other biofuels, biomethane is attractive because the yield of biomass to fuel conversion is higher. Valorisation of biomass will also be achieved through the production of biologicals. Significant progress has been made in the development of chloroplast genetic engineering in microalgae such as Chlamydomonas, however the commercial exploitation of this technology still requires additional research. SUNBIOPATH will address the problem of maximising transgenic expression in the chloroplast and will develop a robust system for chloroplast metabolic engineering by developing methodologies such as inducible expression and trans-operon expression. A techno economic analysis will be made to evaluate the feasibility of using these algae for the purposes proposed (biologicals production in the chloroplast and/or biomethane production) taking into account their role in CO2 mitigation.
Based on the Ac/Ds two element transposition system from maize an activation tagging approach is suggested for the hybrid aspen (Populus tremula x tremuloides) line -Esch5-. The proposed approach is based on results obtained from our earlier work on the genetic transfer of the maize transposable element Ac and its functional analysis in hybrid and pure aspen lines. It was shown that the Ac element is active in aspen and reintegrates elsewhere in genomic regions in high frequency. However, a two element transposon tagging system where Ac and Ds are put together in crosses is not feasible in trees due to the in part long vegetative phases. To overcome this barrier, an inducible two element Ac/ATDs element system is suggested to induce activation tagged variants following two independent transformation steps. In combination with a 35S enhancer tetramer and outward facing two CaMV 35S promoter located near both ends of the ATDs element, expression of genes can be elevated which are located adjacent to the new integration site of the element. As selective marker for ATDs transposition, both knocking-out the expression of a phenotypic marker (rolC gene) and a negative selection marker gene (tms) are considered. Thus, the transposition can easily be screened in primary transgenic lines.
Establishment of modified genes If genes from genetically modified plants were to be passed on to their wild relatives, there could be serious ecological consequences, particularly if these genes were to become established in the genomes of wild plants. So far, little is known about these processes. Background One possible risk associated with genetically modified crop plants is the propagation of their genes through cross-breeding with closely related species. Scientists are seeking to assess whether resistance could be transferred from crop plants to weeds in this way and subsequently propagated in the weeds. If this was the case, these weeds would also become resistant to diseases or herbicides, an undesirable side effect. Objectives Hybrids of transgenic wheat and a close relative, jointed goatgrass (Aegilops cylindrica), will be grown under greenhouse conditions to generate information on the propagation of modified genes and whether they can become established in the genome of a wild species over several generations. The ecological consequences of this type of gene transfer will be investigated as part of the field trial with transgenic wheat (cf. Keller project I). Methods A first generation of transgenic wheat and jointed goatgrass hybrids will be bred in a greenhouse trial. Subsequent generations will be studied to see how the transgenic sequences from the wheat are passed on in the hybrids and how active they are. In addition, the ecological consequences will be assessed in a field trial. Significance There is already considerable information about the risk of cross-breeding between transgenic crop plants and their wild relatives, but little is known about the ecological consequences. The project closes this gap by investigating how the modified genes from transgenic wheat can be inherited in cross-breeding with goatgrass and whether the resulting plants have new ecological traits such as undesirable resistance.
Mit der weltweiten Nutzung von Insektiziden stieg die Anzahl an resistenten Insekten-Arten bis 2006 auf etwa 550 Arten an. Selbst bei gezielter Anwendung von Insektiziden - zur Bekämpfung von Schädlingen in der Landwirtschaft zum Schutz der Ernten und zur Bekämpfung von Krankheitsüberträgern - kommen neben Zielorganismen auch Nicht-Zielorganismen in Kontakt mit den Wirkstoffen. Auf diese Weise entwickeln neben Zielorganismen, wie z.B. der Weißen Fliege, auch Nicht-Zielorganismen, wie z.B. die Taufliege Drosophila melanogaster, Resistenzen. Zu den weit verbreiteten Mechanismen, die Resistenzen bei Insekten auslösen, zählen sowohl die enzymatische Detoxifizierung als auch die Zielort-Unempfindlichkeit. Im ersten Fall begründet sich die Resistenz auf der Tatsache, dass das entsprechende Insekt über ein Enzym verfügt, das in der Lage ist, das betreffende Insektizid mit ausreichend hoher Geschwindigkeit zu Metaboliten umzusetzen, die eine geringere insektizide Wirkung aufweisen. Auf genetischer Ebene bedeutet das, (...) Das Projekt beschäftigt sich mit der P450-Monooxygenase CYP6G1 aus der Taufliege Drosophila melanogaster. Aus genetischen Studien ist bekannt, dass das Cyp6g1-Gen in resistenten Drosophila-Stämmen überexprimiert wird. Eine künstliche Überexpression von Cyp6g1 in Fliegen eines suszeptiblen Drosophila-Stamms führte zur Insektizid-Resistenz. Es wird vermutet, dass das CYP6G1-Enzym die Resistenz des Insekts bewirkt, indem bestimmte Insektizide, wie z.B. Imidacloprid und DDT, durch Metabolisierung detoxifiziert werden. Diese Hypothese soll im Projekt geprüft werden. P450-transgene Tabak-Zellsuspensionskulturen haben sich in unserer Arbeitsgruppe als geeignete in vivo-Systeme zur Untersuchung der Metabolismuskapazität von P450-Enzymen erwiesen. Der gleiche Ansatz wird beim CYP6G1 aus Drosophila melanogaster verfolgt. Im ersten Schritt werden Tabak-Zellsuspensionskulturen mit der cDNA-Sequenz des Cyp6g1 stabil transformiert. Mit den Cyp6g1-transgenen und den unmodifizierten Tabak-Kulturen werden nachfolgend Metabolismusexperimente durchgeführt, wobei z.B. Imidacloprid oder DDT (jeweils in 14C-markierter Form) eingesetzt werden. Durch Vergleich der nicht-transgenen mit der transgenen Tabak-Zellsuspensionskultur kann dann auf die Metabolismusaktivität des CYP6G1-Enzyms bezüglich des eingesetzten Insektizids geschlossen werden. Wichtige Metaboliten können identifiziert und isoliert werden. Der Nachweis, dass das heterolog exprimierte CYP6G1-Enzym das entsprechende Insektizid zu Verbindungen umsetzt, die keine insektizide Wirkung mehr zeigen, stellt dann das letzte Glied in der Beweiskette zur Ursache dieser Insektizid-Resistenz in Drosophila melanogaster dar. Die Prozedur ist analog auf andere Resistenz-Gene (Metabolismus-bedingt) anwendbar. Die resultierenden Erkenntnisse können im günstigen Fall genutzt werden, um (neue) Insektizide zu finden, die vom Resistenzmechanismus unberührt bleiben und deshalb der bestehenden Resistenz entgegenwirken.
Im Rahmen eines Vorlaeuferprojektes (TMWFK FKZ: B305-95001) wurde gezeigt, dass unter den Bedingungen des Bienendarms fremde DNA von Endosymbionten aufgenommen werden kann. Fragmente des PAT-Gens konnten auch nach laengerer Passage ausserhalb des Bienendarms nachgewiesen werden. Im vorliegenden Projekt soll geklaert werden, ob tatsaechlich eine Kopie des Transgens in den untersuchten Mikroorganismen vorlag. Dazu werden weiterfuehrende Untersuchungen an den Proben durchgefuehrt. Durch Sequenzanalyse der PCR-Fragmente soll zunaechst abgesichert werden, in welcher Form die aufgenommenen DNA-Fragmente im Genom der Mikroorganismen vorliegen. Parallel zur Analyse auf die Uebertragung des PAT-Gens soll auch die Moeglichkeit der Uebertragung eines natuerlichen pflanzlichen Gens als Bezug untersucht werden. Diese Arbeiten werden durch die Analyse von Endosymbiontenproben aus Langzeitversuchen ergaenzt, in denen gezeigt werden soll, ob eine laengere Exposition mit transgenen Pollen zu einem Anstieg der Genuebertragung fuehrt.
Glufosinat (oder Phosphinotricin) ist ein vergleichsweise modernes Herbizid, das seit etwa 25 Jahren in Gebrauch ist. Bei der Verbindung handelt es sich um eine Aminosäure; üblicherweise bezeichnet man das DL-Racemat als Glufosinat, das L-Enantiomer als Phosphinothricin. Die Verbindung ist Teilstruktur eines von den Pilzen Streptomyces viridochromogenes und Streptomyces hygroscopicus produzierten natürlichen Antibiotikums (Tripeptid: L-Alanin-L-Alanin-L-Phosphinothricin). Neben seiner antibakteriellen Wirkung zeigt Glufosinat eine nicht-selektive herbizide Wirkung. Der antibakterielle und herbizide Effekt geht nur vom L-Enantiomer aus; das D-Enantiomer ist inaktiv. Sowohl Glufosinat (Racemat) als auch das Tripeptid (Bialaphos oder Bilanaphos; mit L-Enantiomer) werden als Herbizide vermarktet. Die herbizide Wirkung von Phosphinothricin beruht auf einer Inhibition der Glutaminsynthetase. Glufosinat weist günstige ökotoxikologische Eigenschaften auf, z.B. bezüglich Versickerung, Abbau sowie Toxizität gegenüber Tier und Mensch. Auf Grund dieser Eigenschaften ist Glufosinat ein geeigneter Kandidat zur Herstellung gentechnisch modifizierter Herbizid-resistenter Pflanzen, um Glufosinat auch selektiv - im Nachauflauf - einsetzen zu können. Dazu wurden verschiedene Spezies, wie z.B. die Zuckerrübe, mit dem bar-Gen aus Streptomyces hygroscopicus transformiert. Das bar-Gen codiert für eine Phosphinothricin-N-acetyltransferase, die Phosphinothricin zum nicht herbizid-wirksamen, stabilen N-Acetylderivat umsetzt. Bei entsprechend hoher Expression des bar-Gens resultiert eine Glufosinat-resistente Pflanze. Ein Ziel unseres Forschungsvorhabens war es, den Metabolismus von Glufosinat und der einzelnen Enantiomere (L- und D-Phyosphinothricin) in transgenen und nicht transgenen Pflanzenzellkulturen zu untersuchen. Die transgenen Kulturen, die von der Zuckerrübe (Beta vulgaris) stammten, waren mit dem bar-Gen transformiert, exprimierten demnach die Phosphinothricin-N-acetyltransferase. Sie wurden aus entsprechenden Sprosskulturen initiiert. Daneben wurden nicht-transgene Kulturen von Zuckerrübe, Karotte (Daucus carota), Fingerhut (Digitalis purpurea) und Stechapfel (Datura stramonium) untersucht. In einer zweiten Versuchsserie wurden abgetrennte Sprosse und Blätter von 20 Wildpflanzen auf den Metabolismus von Glufosinat untersucht. Es sollte überprüft werden, ob qualitative und quantitative Unterschiede im Umsatz des Herbizids im Pflanzenreich vorkommen und möglicherweise eine natürliche (teilweise) Resistenz gegenüber Glufosinat existiert. Schließlich wurde das Schicksal des Herbizids im Boden (Abbau, Versickerung) nach Aufbringung des Wirksstoffs in einer handelsüblichen Formulierung auf ein bewachsenes Versuchsfeld im Freiland untersucht.
What impact does transgenic maize have on soil fertility? Among the factors that determine soil fertility is the diversity of the bacteria living in it. This is in turn affected by the form of agriculture practiced on the land. What role do transgenic plants play in this interaction? Background Soil fertility is the product of the interactions between the parental geological material from which the soil originated, the climate and colonization by soil organisms. Soil organisms and their diversity play a major role in soil fertility, and these factors can be affected by the way the soil is managed. The type of farming, i.e. how fertilizers and pesticides are used, has a major impact on the fertility of the soil. It is known that the complex interaction of bacterial diversity and other soil properties regulates the efficacy of plant resistance. But little is known about how transgenic plants affect soil fertility. Objectives The project will investigate selected soil processes as indicators for how transgenic maize may possibly alter soil fertility. The intention is in particular to establish whether the soil is better able to cope with such effects if it contains a great diversity of soil bacteria. Methods Transgenic maize will be planted in climate chambers containing soils managed in different ways. The soil needed for these trials originates from open field trials that have been used for decades to compare various forms of organic and conventional farming. These soils differ, for example, in the way they have been treated with pesticides and fertilizers and thus also with respect to their diversity of bacteria. The trial with transgenic maize will measure various parameters: the number of soil bacteria and the diversity of their species, the quantity of a small number of selected nutrients and the decomposition of harvest residues. It will be possible to conclude from this work how transgenic plants affect soil fertility. Significance The project will create an important basis for developing risk assessments that incorporate the effects of transgenic plants on soil fertility.
How does fungal resistance of transgenic wheat behave in the open? Fungi, and most particularly mildew, cause enormous losses in wheat harvests. To overcome this, wheat was genetically engineered to resist mildew. But there is still very little information about how this resistance functions in open cultivation. Background Mildew and other fungi cause tremendous damage in wheat production, necessitating the use of sprayed crop-protection products. It has been possible to use genetic engineering to overcome this problem by incorporating a specific barley gene in the wheat genome. This gene produces proteins that degrade the cell walls of fungi and destroy the pests. Little is known, though, about the efficacy of this method in open cultivation or the conceivable risks. Objectives The project aims to investigate how fungal resistance in genetically modified wheat behaves in the open. The aim is to measure the efficacy of this resistance against fungal diseases and to assess the potential benefit for agriculture. Methods The efficacy of mildew resistance will be investigated in three successive years as part of the field trial with transgenic wheat (cf. Keller project I). Among other things, the activity of the resistance genes and the productivity of the wheat lines will be measured. Parallel trials will check the results of the field trial under greenhouse conditions. Significance Plants behave differently in the greenhouse and in the open. It is therefore necessary to test the action of the additional resistance genes in field trials. This project will evaluate both resistance to true mildew and resistance to other pathogenic fungi.
| Origin | Count |
|---|---|
| Bund | 30 |
| Type | Count |
|---|---|
| Förderprogramm | 30 |
| License | Count |
|---|---|
| offen | 30 |
| Language | Count |
|---|---|
| Deutsch | 16 |
| Englisch | 24 |
| Resource type | Count |
|---|---|
| Keine | 26 |
| Webseite | 4 |
| Topic | Count |
|---|---|
| Boden | 26 |
| Lebewesen & Lebensräume | 30 |
| Luft | 23 |
| Mensch & Umwelt | 30 |
| Wasser | 23 |
| Weitere | 30 |