Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
Seit Februar 2021 bietet Wolfgang Brandt, ehemaliger Leiter der Arbeitsgruppe Computerchemie am IPB, sein Citizen Science-Projekt zur Pilzbestimmung an. Dafür hat er in regelmäßigen Abständen öffentliche Vorträge zur Vielfalt…
Walter, M. H.; Floß, D. S.; Hans, J.; Fester, T.; Strack, D.;Apocarotenoid biosynthesis in arbuscular mycorrhizal roots: Contributions from methylerythritol phosphate pathway isogenes and tools for its manipulationPhytochemistry68130-138(2007)DOI: 10.1016/j.phytochem.2006.09.032
During colonization by arbuscular mycorrhizal (AM) fungi plant roots frequently accumulate two types of apocarotenoids (carotenoid cleavage products). Both compounds, C14 mycorradicin and C13 cyclohexenone derivatives, are predicted to originate from a common C40 carotenoid precursor. Mycorradicin is the chromophore of the “yellow pigment” responsible for the long-known yellow discoloration of colonized roots. The biosynthesis of apocarotenoids has been investigated with a focus on the two first steps of the methylerythritol phosphate (MEP) pathway catalyzed by 1-deoxy-d-xylulose 5-phosphate synthase (DXS) and 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR). In Medicago truncatula and other plants the DXS2 isogene appears to be specifically involved in the AM-mediated accumulation of apocarotenoids, whereas in the case of DXR a single gene contributes to both housekeeping and mycorrhizal (apo)carotenoid biosynthesis. Immunolocalization of DXR in mycorrhizal maize roots indicated an arbuscule-associated protein deposition, which occurs late in arbuscule development and accompanies arbuscule degeneration and breakdown. The DXS2 isogene is being developed as a tool to knock-down apocarotenoid biosynthesis in mycorrhizal roots by an RNAi strategy. Preliminary results from this approach provide starting points to suggest a new kind of function for apocarotenoids in mycorrhizal roots.
Publikation
Fester, T.; Lohse, S.; Halfmann, K.;“Chromoplast” development in arbuscular mycorrhizal rootsPhytochemistry6892-100(2007)DOI: 10.1016/j.phytochem.2006.09.034
The accumulation of apocarotenoids in arbuscular mycorrhizal (AM) roots suggests a dramatic reorganization of the plastids responsible for the biosynthesis of these compounds. This review describes the cytological and biochemical characterization of this phenomenon. The results presented suggest that plastids are key organelles for the establishment of the symbiotic interface of the AM symbiosis. In addition, a complex interplay of various plant cell components during the different functional phases of this interface is suggested. Arbuscule degradation appears to be of particular interest, as it correlates with the formation of the most extensive plastid structures and with apocarotenoid accumulation.
Publikation
Fester, T.; Hause, B.;Drought and symbiosis – why is abscisic acid necessary for arbuscular mycorrhiza?New Phytol.175383-386(2007)DOI: 10.1111/j.1469-8137.2007.02171.x
Lohse, S.; Hause, B.; Hause, G.; Fester, T.;FtsZ Characterization and Immunolocalization in the Two Phases of Plastid Reorganization in Arbuscular Mycorrhizal Roots of Medicago truncatulaPlant Cell Physiol.471124-1134(2006)DOI: 10.1093/pcp/pcj083
We have analyzed plastid proliferation in root cortical cells of Medicago truncatula colonized by arbuscular mycorrhizal (AM) fungi by concomitantly labeling fungal structures, root plastids, a protein involved in plastid division (FtsZ1) and a protein involved in the biosynthesis of AM-specific apocarotenoids. Antibodies directed against FtsZ1 have been generated after heterologous expression of the respective gene from M. truncatula and characterization of the gene product. Analysis of enzymatic activity and assembly experiments showed similar properties of this protein when compared with the bacterial proteins. Immunocytological experiments allowed two phases of fungal and plastid development to be clearly differentiated and plastid division to be monitored during these phases. In the early phase of arbuscule development, lens-shaped plastids, intermingled with the arbuscular branches, divide frequently. Arbuscule degradation, in contrast, is characterized by large, tubular plastids, decorated by a considerable number of FtsZ division rings.