zur Suche springenzur Navigation springenzum Inhalt springen

Publikationen - Stoffwechsel- und Zellbiologie

Sortieren nach: Erscheinungsjahr Typ der Publikation

Zeige Ergebnisse 91 bis 100 von 480.

Preprints

Ordon, J.; Bressan, M.; Kretschmer, C.; Dall'Osto, L.; Marillonnet, S.; Bassi, R.; Stuttmann, J.; Optimized Cas9 expression systems for highly efficient Arabidopsis genome editing facilitate isolation of complex alleles in a single generation bioRxiv (2018) DOI: 10.1101/393439

Genetic resources for the model plant Arabidopsis comprise mutant lines defective in almost any single gene in reference accession Columbia. However, gene redundancy and/or close linkage often render it extremely laborious or even impossible to isolate a desired line lacking a specific function or set of genes from segregating populations. Therefore, we here evaluated strategies and efficiencies for the inactivation of multiple genes by Cas9-based nucleases and multiplexing. In first attempts, we succeeded in isolating a mutant line carrying a 70 kb deletion, which occurred at a frequency of ~1.6% in the T2 generation, through PCR-based screening of numerous individuals. However, we failed to isolate a line lacking Lhcb1 genes, which are present in five copies organized at two loci in the Arabidopsis genome. To improve efficiency of our Cas9-based nuclease system, regulatory sequences controlling Cas9 expression levels and timing were systematically compared. Indeed, use of DD45 and RPS5a promoters improved efficiency of our genome editing system by approximately 25-30-fold in comparison to the previous ubiquitin promoter. Using an optimized genome editing system with RPS5a promoter-driven Cas9, putatively quintuple mutant lines lacking detectable amounts of Lhcb1 protein represented approximately 30% of T1 transformants. These results show how improved genome editing systems facilitate the isolation of complex mutant alleles, previously considered impossible to generate, at high frequency even in a single (T1) generation.
Publikation

Xu, H.; Lybrand, D.; Bennewitz, S.; Tissier, A.; Last, R. L.; Pichersky, E.; Production of trans-chrysanthemic acid, the monoterpene acid moiety of natural pyrethrin insecticides, in tomato fruit Metab. Eng. 47, 271-278, (2018) DOI: 10.1016/j.ymben.2018.04.004

The pyrethrum plant, Tanacetum cinerariifolium (Asteraceae) synthesizes a class of compounds called pyrethrins that have strong insecticidal properties but are safe to humans. Class I pyrethrins are esters of the monoterpenoid trans-chrysanthemic acid with one of three jasmonic-acid derived alcohols. We reconstructed the trans-chrysanthemic acid biosynthetic pathway in tomato fruits, which naturally produce high levels of the tetraterpene pigment lycopene, an isoprenoid which shares a common precursor, dimethylallyl diphosphate (DMAPP), with trans-chrysanthemic acid. trans-Chrysanthemic acid biosynthesis in tomato fruit was achieved by expressing the chrysanthemyl diphosphate synthase gene from T. cinerariifolium, encoding the enzyme that uses DMAPP to make trans-chrysanthemol, under the control of the fruit specific promoter PG, as well as an alcohol dehydrogenease (ADH) gene and aldehyde dehydrogenase (ALDH) gene from a wild tomato species, also under the control of the PG promoter. Tomato fruits expressing all three genes had a concentration of trans-chrysanthemic acid that was about 1.7-fold higher (by weight) than the levels of lycopene present in non-transgenic fruit, while the level of lycopene in the transgenic plants was reduced by 68%. Ninety seven percent of the diverted DMAPP was converted to trans-chrysanthemic acid, but 62% of this acid was further glycosylated. We conclude that the tomato fruit is an alternative platform for the biosynthesis of trans-chrysanthemic acid by metabolic engineering.
Publikation

Wasternack, C.; Hause, B.; A Bypass in Jasmonate Biosynthesis – the OPR3-independent Formation Trends Plant Sci. 23, 276-279, (2018) DOI: 10.1016/j.tplants.2018.02.011

For the first time in 25 years, a new pathway for biosynthesis of jasmonic acid (JA) has been identified. JA production takes place via 12-oxo-phytodienoic acid (OPDA) including reduction by OPDA reductases (OPRs). A loss-of-function allele, opr3-3, revealed an OPR3-independent pathway converting OPDA to JA.
Publikation

Vogt, T.; Unusual spermine-conjugated hydroxycinnamic acids on pollen: function and evolutionary advantage J. Exp. Bot. 69, 5311-5315, (2018) DOI: 10.1093/jxb/ery359

Conjugates between polyamines and hydroxycinnamic acids are found on the pollen surface of all higher plants, both mono- and dicots. But we don’t know why they are there. Delporte et al. (2018) have now shown that in the tapetum of the Asteraceae (sunflower family) a new type of BAHD-acyltransferase is expressed, able to transfer coenzyme A-activated coumaric acid to all four primary and secondary amine groups of the polyamine spermine. In the case of chicory this sequential addition results in a fully substituted tetracoumaroyl–spermine conjugate and points to an evolutionary advantage of these functionally enigmatic compounds.
Publikation

van Aubel, G.; Serderidis, S.; Ivens, J.; Clinkemaillie, A.; Legrève, A.; Hause, B.; Van Cutsem, P.; Oligosaccharides successfully thwart hijacking of the salicylic acid pathway by Phytophthora infestans in potato leaves Plant Pathol. 67, 1901-1911, (2018) DOI: 10.1111/ppa.12908

Potato growing is severely threatened by the late blight agent Phytophthora infestans, which is usually controlled by massive amounts of fungicides. While variety resistance is often bypassed by the pathogen, the plant innate immunity opens the way to new biological plant protection tools e.g. the COS‐OGA elicitor. This oligosaccharide composition mimics the interaction between plants and fungal pathogens as it combines chitosan oligomers (COS) with pectin‐derived oligogalacturonides (OGA).Two different COS‐OGA elicitors were evaluated against potato late blight: FytoSave® mainly efficient against powdery mildews and FytoSol, a new composition still under development. Next to the evaluation of their protective effect, a comparative study of plant defense induction was performed focusing on the effect of repeated sprayings as well as on the stimulation of salicylic acid (SA), jasmonic acid and ethylene‐related pathways during the biotrophic and the necrotrophic growth stages of the pathogen.The FytoSave® elicitor strongly increased the SA content but failed to induce a sufficient protection against late blight while FytoSol maintained or even decreased the free SA content in presence of P. infestans and was completely efficient. Surprisingly, the necrotrophic development of P. infestans occurred along with a strong leaf accumulation of free SA and SA‐related transcripts. It may represent an attempt by P. infestans to divert plant defenses for its own benefit. Preventive sprayings with FytoSol but not FytoSave® completely impeded this hijacking. FytoSol seemed to keep the SA pathway under control, thereby preventing its diversion by P. infestans.
Publikation

Tissier, A.; Plant secretory structures: more than just reaction bags Curr. Opin. Biotech. 49, 73-79, (2018) DOI: 10.1016/j.copbio.2017.08.003

Plants have a remarkable capacity for the production of a wide range of metabolites. Much has been reported and reviewed on the diversity of these metabolites and how it is achieved, for example through the evolution of enzyme families. In comparison, relatively little is known on the extraordinary metabolic productivity of dedicated organs where many of these metabolites are synthesized and accumulate. Plant glandular trichomes are such specialized metabolite factories, for which recent omics analyses have shed new light on the adaptive metabolic strategies that support high metabolic fluxes. In photosynthetic trichomes such as those of the Solanaceae, these include CO2 refixation and possibly C4-like metabolism which contribute to the high productivity of these sink organs.
Publikation

Tannert, M.; May, A.; Ditfe, D.; Berger, S.; Balcke, G. U.; Tissier, A.; Köck, M.; Pi starvation-dependent regulation of ethanolamine metabolism by phosphoethanolamine phosphatase PECP1 in Arabidopsis roots J. Exp. Bot. 69, 467-481, (2018) DOI: 10.1093/jxb/erx408

A universal plant response to phosphorus deprivation is the up-regulation of a diverse array of phosphatases. As reported recently, the AtPECP1 gene encodes a phosphatase with in vitro substrate specificity for phosphoethanolamine and phosphocholine. The putative substrates suggested that AtPECP1 is related to phospholipid metabolism; however, the biological function of AtPECP1 is as yet not understood. In addition, whereas lipid remodelling processes as part of the phosphorus starvation response have been extensively studied, knowledge of the polar head group metabolism and its regulation is lacking. We found that AtPECP1 is expressed in the cytosol and exerts by far its strongest activity in roots of phosphate-starved plants. We established a novel LC-MS/MS-based method for the quantitative and simultaneous measurement of the head group metabolites. The analysis of Atpecp1 null mutants and overexpression lines revealed that phosphoethanolamine, but not phosphocholine is the substrate of AtPECP1 in vivo. The impact on head group metabolite levels is greatest in roots of both loss-of-function and gain-of-function transgenic lines, indicating that the biological role of AtPECP1 is mainly restricted to roots. We suggest that phosphoethanolamine hydrolysis by AtPECP1 during Pi starvation is required to down-regulate the energy-consuming biosynthesis of phosphocholine through the methylation pathway.
Publikation

Stauder, R.; Welsch, R.; Camagna, M.; Kohlen, W.; Balcke, G. U.; Tissier, A.; Walter, M. H.; Strigolactone Levels in Dicot Roots Are Determined by an Ancestral Symbiosis-Regulated Clade of the PHYTOENE SYNTHASE Gene Family Front. Plant Sci. 9, 255, (2018) DOI: 10.3389/fpls.2018.00255

Strigolactones (SLs) are apocarotenoid phytohormones synthesized from carotenoid precursors. They are produced most abundantly in roots for exudation into the rhizosphere to cope with mineral nutrient starvation through support of root symbionts. Abscisic acid (ABA) is another apocarotenoid phytohormone synthesized in roots, which is involved in responses to abiotic stress. Typically low carotenoid levels in roots raise the issue of precursor supply for the biosynthesis of these two apocarotenoids in this organ. Increased ABA levels upon abiotic stress in Poaceae roots are known to be supported by a particular isoform of phytoene synthase (PSY), catalyzing the rate-limiting step in carotenogenesis. Here we report on novel PSY3 isogenes from Medicago truncatula (MtPSY3) and Solanum lycopersicum (SlPSY3) strongly expressed exclusively upon root interaction with symbiotic arbuscular mycorrhizal (AM) fungi and moderately in response to phosphate starvation. They belong to a widespread clade of conserved PSYs restricted to dicots (dPSY3) distinct from the Poaceae-PSY3s involved in ABA formation. An ancient origin of dPSY3s and a potential co-evolution with the AM symbiosis is discussed in the context of PSY evolution. Knockdown of MtPSY3 in hairy roots of M. truncatula strongly reduced SL and AM-induced C13 α-ionol/C14 mycorradicin apocarotenoids. Inhibition of the reaction subsequent to phytoene synthesis revealed strongly elevated levels of phytoene indicating induced flux through the carotenoid pathway in roots upon mycorrhization. dPSY3 isogenes are coregulated with upstream isogenes and downstream carotenoid cleavage steps toward SLs (D27, CCD7, CCD8) suggesting a combined carotenoid/apocarotenoid pathway, which provides “just in time”-delivery of precursors for apocarotenoid formation.
Publikation

Bennewitz, S.; Bergau, N.; Tissier, A.; QTL Mapping of the Shape of Type VI Glandular Trichomes in Tomato Front. Plant Sci. 9, 1421, (2018) DOI: 10.3389/fpls.2018.01421

Glandular trichomes contribute to the high resistance of wild tomato species against insect pests not only thanks to the metabolites they produce but also because of morphological and developmental features which support the high production of these defense compounds. In Solanum habrochaites, type VI trichomes have a distinct spherical shape and a large intercellular storage cavity where metabolites can accumulate and are released upon breaking off of the glandular cells. In contrast, the type VI trichomes of S. lycopersicum have a four-leaf clover shape corresponding to the four glandular cells and a small internal cavity with limited capacity for storage of compounds. To better characterize the genetic factors underlying these trichome morphological differences we created a back-cross population of 116 individuals between S. habrochaites LA1777 and S. lycopersicum var. cerasiforme WVa106. A trichome score that reflects the shape of the type VI trichomes allowing the quantification of this trait was designed. The scores were distributed normally across the population, which was mapped with a total of 192 markers. This resulted in the identification of six quantitative trait locus (QTLs) on chromosomes I, VII, VII, and XI. The QTL on chromosome I with the highest LOD score was confirmed and narrowed down to a 500 gene interval in an advanced population derived from one of the back-cross lines. Our results provide the foundation for the genetic dissection of type VI trichome morphology and the introgression of these trichome traits into cultivated tomato lines for increased insect resistance.
Publikation

Akaberi, S.; Wang, H.; Claudel, P.; Riemann, M.; Hause, B.; Hugueney, P.; Nick, P.; Grapevine fatty acid hydroperoxide lyase generates actin-disrupting volatiles and promotes defence-related cell death J. Exp. Bot. 69, 2883-2896, (2018) DOI: 10.1093/jxb/ery133

Fatty acid hydroperoxides can generate short-chained volatile aldehydes that may participate in plant defence. A grapevine hydroperoxide lyase (VvHPL1) clustering to the CYP74B class was functionally characterized with respect to a role in defence. In grapevine leaves, transcripts of this gene accumulated rapidly to high abundance in response to wounding. Cellular functions of VvHPL1 were investigated upon heterologous expression in tobacco BY-2 cells. A C-terminal green fluorescent protein (GFP) fusion of VvHPL1 was located in plastids. The overexpression lines were found to respond to salinity stress or the bacterial elicitor harpin by increasing cell death. This signal-dependent mortality response was mitigated either by addition of exogenous jasmonic acid or by treatment with diphenyleneiodonium (DPI), an inhibitor of NADPH oxidases. By feeding different substrates to recombinantly expressed enzyme, VvHPL1 could also be functionally classified as true 13-HPL. The cognate products generated by this 13-HPL were cis-3-hexenal and trans-2-hexenal. Using a GFP-tagged actin marker line, one of these isomeric products, cis-3-hexenal, was found specifically to elicit a rapid disintegration of actin filaments. This response was not only observed in the heterologous system (tobacco BY-2), but also in a grapevine cell strain expressing this marker, as well as in leaf discs from an actin marker grape used as a homologous system. These results are discussed in the context of a role for VvHPL1 in a lipoxygenase-dependent signalling pathway triggering cell death-related defence that bifurcates from jasmonate-dependent basal immunity.
  • Die Leibniz-Gemeinschaft
  • Digitalisierung in der Landwirtschaft
  • Martin-Luther Universität Halle
IPB Mainnav Search