Unser 10. Leibniz Plant Biochemistry Symposium am 7. und 8. Mai war ein großer Erfolg. Thematisch ging es in diesem Jahr um neue Methoden und Forschungsansätze der Naturstoffchemie. Die exzellenten Vorträge über Wirkstoffe…
Omanische Heilpflanze im Fokus der Phytochemie IPB-Wissenschaftler und Partner aus Dhofar haben jüngst die omanische Heilpflanze Terminalia dhofarica unter die phytochemische Lupe genommen. Die Pflanze ist reich an…
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…
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.
Publikation
Fortes, A. M.; Miersch, O.; Lange, P. R.; Malhó, R.; Testillano, P. S.; Risueño, M. d. C.; Wasternack, C.; Pais, M. S.;Expression of Allene Oxide Cyclase and Accumulation of Jasmonates during Organogenic Nodule Formation from Hop (Humulus lupulus var. Nugget) InternodesPlant Cell Physiol.461713-1723(2005)DOI: 10.1093/pcp/pci187
A crucial step in the biosynthesis of jasmonic acid (JA) is the formation of its stereoisomeric precursor, cis-(+)-12-oxophytodienoic acid (OPDA), which is catalyzed by allene oxide cyclase (AOC, EC 5.3.99.6). A cDNA of AOC was isolated from Humulus lupulus var. Nugget. The ORF of 765 bp encodes a 255 amino acid protein, which carries a putative chloroplast targeting sequence. The recombinant protein without its putative chloroplast target sequence showed significant AOC activity. Previously we demonstrated that wounding induces organogenic nodule formation in hop. Here we show that the AOC transcript level increases in response to wounding of internodes, peaking between 2 and 4 h after wounding. In addition, Western blot analysis showed elevated levels of AOC peaking 24 h after internode inoculation. The AOC increase was accompanied by increased JA levels 24 h after wounding, whereas OPDA had already reached its highest level after 12 h. AOC is mostly present in the vascular bundles of inoculated internodes. During prenodule and nodule formation, AOC levels were still high. JA and OPDA levels decreased down to 10 and 118 pmol (g FW)–1, respectively, during nodule formation, but increased during plantlet regeneration. Double immunolocalization analysis of AOC and Rubisco in connection with lugol staining showed that AOC is present in amyloplasts of prenodular cells and in the chloroplasts of vacuolated nodular cells, whereas meristematic cells accumulated little AOC. These data suggest a role of AOC and jasmonates in organogenic nodule formation and plantlet regeneration from these nodules.
Publikation
Schaarschmidt, S.; Qu, N.; Strack, D.; Sonnewald, U.; Hause, B.;Local Induction of the alc Gene Switch in Transgenic Tobacco Plants by AcetaldehydePlant Cell Physiol.451566-1577(2004)DOI: 10.1093/pcp/pch177
The alc promoter system, derived from the filamentous fungi Aspergillus nidulans, allows chemically regulated gene expression in plants and thereby the study of gene function as well as metabolic and developmental processes. In addition to ethanol, this system can be activated by acetaldehyde, described as the physiological inducer in A. nidulans. Here, we show that in contrast to ethanol, acetaldehyde allows tissue-specific activation of the alc promoter in transgenic tobacco plants. Soil drenching with aqueous acetaldehyde solutions at a concentration of 0.05% (v/v) resulted in the rapid and temporary induction of the alc gene expression system exclusively in roots. In addition, the split root system allows activation to be restricted to the treated part of the root. The temporary activation of the alc system by soil drenching with acetaldehyde could be prolonged over several weeks by subsequent applications at intervals of 7 d. This effect was demonstrated for the root-specific induction of a yeast-derived apoplast-located invertase under the control of the alcohol-inducible promoter system. In leaves, which exhibit a lower responsiveness to acetaldehyde than roots, the alc system was induced in the directly treated tissue only. Thus, acetaldehyde can be used as a local inducer of the alc gene expression system in tobacco plants.
Publikation
Doll, J.; Hause, B.; Demchenko, K.; Pawlowski, K.; Krajinski, F.;A Member of the Germin-Like Protein Family is a Highly Conserved Mycorrhiza-Specific Induced GenePlant Cell Physiol.441208-1214(2003)DOI: 10.1093/pcp/pcg153
A Medicago truncatula cDNA encoding a germin-like protein (GLP) was isolated from a suppression subtractive hybridization cDNA library enriched for arbuscular mycorrhiza (AM)-induced genes. The MtGLP1 amino acid sequence shows some striking differences to previously described plant GLP sequences and might therefore represent a new subgroup of this multigene family. The MtGlp1 mRNA was strongly induced in roots and root cultures colonized by the AM fungus Glomus intraradices. Whereas MtGlp1 is strongly induced in AM, no transcripts of the gene were detected in non-infected roots or in roots after infection with the oomycete root pathogen Aphanomyces euteiches or with Rhizobia. Increased phosphate levels during fertilization also could not stimulate MtGlp1 transcription. Hence, MtGlp1 induction seems to be an AM-specific phenomenon. In situ hybridization showed that MtGlp1 is localized in arbuscule containing cells. A putative orthologue of this AM-specific GLP gene could be localized in a second legume Lotus japonicus, indicating that the regulation of a member of the GLP family belongs to a conserved mechanism in AM regulation in different plant species.