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Publications - Cell and Metabolic Biology

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Publications

Scheler, U.; Brandt, W.; Porzel, A.; Rothe, K.; Manzano, D.; Božić, D.; Papaefthimiou, D.; Balcke, G. U.; Henning, A.; Lohse, S.; Marillonnet, S.; Kanellis, A. K.; Ferrer, A.; Tissier, A.; Elucidation of the biosynthesis of carnosic acid and its reconstitution in yeast Nat. Commun. 7, 12942, (2016) DOI: 10.1038/ncomms12942

Rosemary extracts containing the phenolic diterpenes carnosic acid and its derivative carnosol are approved food additives used in an increasingly wide range of products to enhance shelf-life, thanks to their high anti-oxidant activity. We describe here the elucidation of the complete biosynthetic pathway of carnosic acid and its reconstitution in yeast cells. Cytochrome P450 oxygenases (CYP76AH22-24) from Rosmarinus officinalis and Salvia fruticosa already characterized as ferruginol synthases are also able to produce 11-hydroxyferruginol. Modelling-based mutagenesis of three amino acids in the related ferruginol synthase (CYP76AH1) from S. miltiorrhiza is sufficient to convert it to a 11-hydroxyferruginol synthase (HFS). The three sequential C20 oxidations for the conversion of 11-hydroxyferruginol to carnosic acid are catalysed by the related CYP76AK6-8. The availability of the genes for the biosynthesis of carnosic acid opens opportunities for the metabolic engineering of phenolic diterpenes, a class of compounds with potent anti-oxidant, anti-inflammatory and anti-tumour activities.
Publications

Fester, T.; Lohse, S.; Halfmann, K.; “Chromoplast” development in arbuscular mycorrhizal roots Phytochemistry 68, 92-100, (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.
Publications

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 truncatula Plant Cell Physiol. 47, 1124-1134, (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.
Publications

Lohse, S.; Schliemann, W.; Ammer, C.; Kopka, J.; Strack, D.; Fester, T.; Organization and Metabolism of Plastids and Mitochondria in Arbuscular Mycorrhizal Roots of Medicago truncatula Plant Physiol. 139, 329-340, (2005) DOI: 10.1104/pp.105.061457

Colonization of root cortical cells by arbuscular mycorrhizal fungi leads to marked cytological changes of plastids and mitochondria. Plastids in particular are forming tubular extensions partially connecting individual organelles in a network-like way. These cytological changes correspond to an increased need for plastid and mitochondrial products during establishment and functioning of the symbiosis. The analysis of metabolite and transcript levels in mycorrhizal and nonmycorrhizal roots from Medicago truncatula revealed concomitant changes regarding a number of metabolic pathways. Our results indicate the activation of the mitochondrial tricarboxylic acid cycle and of plastid biosynthetic pathways producing fatty acids, amino acids, and apocarotenoids. These observations provide a general overview of structural and metabolic changes of plastids and mitochondria during colonization of root cortical cells by arbuscular mycorrhizal fungi.
Publications

Fester, T.; Schmidt, D.; Lohse, S.; Walter, M. H.; Giuliano, G.; Bramley, P. M.; Fraser, P. D.; Hause, B.; Strack, D.; Stimulation of carotenoid metabolism in arbuscular mycorrhizal roots Planta 216, 148-154, (2002) DOI: 10.1007/s00425-002-0917-z

Development of arbuscular mycorrhizal roots is correlated with accumulation of various isoprenoids, i.e. acyclic C14 polyene 'mycorradicin' and C13 cyclohexenone derivatives. We present data indicating a strong stimulation of carotenoid metabolism in such roots. Carotenoid profiling revealed mycorrhiza-specific accumulation of ζ-carotene in Zea mays and Medicago truncatula. Precursor accumulation after inhibition of phytoene desaturase (Pds) activity by norflurazon indicated an increased phytoene biosynthetic capacity in mycorrhizal roots of all species analyzed. Nicotiana tabacum plants transformed with a PDS promoter-GUS construct showed a cell-specific induction of PDS promoter activity in root cells containing arbuscules. Mycorradicin biosynthesis and, partially, mycorrhization were impaired in maize mutants deficient in carotenoid biosynthesis. These data indicate that (1) mycorradicin is probably synthesized via a C40 precursor carotenoid, (2) carotenoid biosynthesis is induced in mycorrhizal roots, (3) induction occurs, at least partially, at the transcriptional level, and (4) that this may play a functional role during mycorrhization.
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