@article{AnnunziataApeltCarilloetal.2017,
  author    = {Annunziata, Maria Grazia and Apelt, Federico and Carillo, Petronia and Krause, Ursula and Feil, Regina and Mengin, Virginie and Lauxmann, Martin A. and Koehl, Karin and Nikoloski, Zoran and Stitt, Mark and Lunn, John Edward},
  title     = {Getting back to nature: a reality check for experiments in controlled environments},
  series = {Journal of experimental botany},
  volume    = {68},
  journal   = {Journal of experimental botany},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0022-0957},
  doi       = {10.1093/jxb/erx220},
  pages     = {4463 -- 4477},
  year      = {2017},
  abstract  = {Irradiance from sunlight changes in a sinusoidal manner during the day, with irregular fluctuations due to clouds, and light-dark shifts at dawn and dusk are gradual. Experiments in controlled environments typically expose plants to constant irradiance during the day and abrupt light-dark transitions. To compare the effects on metabolism of sunlight versus artificial light regimes, Arabidopsis thaliana plants were grown in a naturally illuminated greenhouse around the vernal equinox, and in controlled environment chambers with a 12-h photoperiod and either constant or sinusoidal light profiles, using either white fluorescent tubes or light-emitting diodes (LEDs) tuned to a sunlight-like spectrum as the light source. Rosettes were sampled throughout a 24-h diurnal cycle for metabolite analysis. The diurnal metabolite profiles revealed that carbon and nitrogen metabolism differed significantly between sunlight and artificial light conditions. The variability of sunlight within and between days could be a factor underlying these differences. Pairwise comparisons of the artificial light sources (fluorescent versus LED) or the light profiles (constant versus sinusoidal) showed much smaller differences. The data indicate that energy-efficient LED lighting is an acceptable alternative to fluorescent lights, but results obtained from plants grown with either type of artificial lighting might not be representative of natural conditions.},
  language  = {en}
}
@phdthesis{Dethloff2013,
  author    = {Dethloff, Frederik},
  title     = {In vivo 13C stable isotope tracing of single leaf development in the cold},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-70486},
  school      = {Universit{\"a}t Potsdam},
  year      = {2013},
  abstract  = {Measuring the metabolite profile of plants can be a strong phenotyping tool, but the changes of metabolite pool sizes are often difficult to interpret, not least because metabolite pool sizes may stay constant while carbon flows are altered and vice versa. Hence, measuring the carbon allocation of metabolites enables a better understanding of the metabolic phenotype. The main challenge of such measurements is the in vivo integration of a stable or radioactive label into a plant without perturbation of the system. To follow the carbon flow of a precursor metabolite, a method is developed in this work that is based on metabolite profiling of primary metabolites measured with a mass spectrometer preceded by a gas chromatograph (Wagner et al. 2003; Erban et al. 2007; Dethloff et al. submitted). This method generates stable isotope profiling data, besides conventional metabolite profiling data. In order to allow the feeding of a 13C sucrose solution into the plant, a petiole and a hypocotyl feeding assay are developed. To enable the processing of large numbers of single leaf samples, their preparation and extraction are simplified and optimised. The metabolite profiles of primary metabolites are measured, and a simple relative calculation is done to gain information on carbon allocation from 13C sucrose. This method is tested examining single leaves of one rosette in different developmental stages, both metabolically and regarding carbon allocation from 13C sucrose. It is revealed that some metabolite pool sizes and 13C pools are tightly associated to relative leaf growth, i.e. to the developmental stage of the leaf. Fumaric acid turns out to be the most interesting candidate for further studies because pool size and 13C pool diverge considerably. In addition, the analyses are also performed on plants grown in the cold, and the initial results show a different metabolite pool size pattern across single leaves of one Arabidopsis rosette, compared to the plants grown under normal temperatures. Lastly, in situ expression of REIL genes in the cold is examined using promotor-GUS plants. Initial results suggest that single leaf metabolite profiles of reil2 differ from those of the WT.},
  language  = {en}
}
@article{FichtnerBarbierAnnunziataetal.2020,
  author    = {Fichtner, Franziska and Barbier, Francois F. and Annunziata, Maria Grazia and Feil, Regina and Olas, Justyna Jadwiga and M{\"u}ller-R{\"o}ber, Bernd and Stitt, Mark and Beveridge, Christine A. and Lunn, John Edward},
  title     = {Regulation of shoot branching in arabidopsis by trehalose 6-phosphate},
  series = {New phytologist : international journal of plant science},
  volume    = {229},
  journal   = {New phytologist : international journal of plant science},
  number    = {4},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0028-646X},
  doi       = {10.1111/nph.17006},
  pages     = {2135 -- 2151},
  year      = {2020},
  abstract  = {Trehalose 6-phosphate (Tre6P) is a sucrose signalling metabolite that has been implicated in regulation of shoot branching, but its precise role is not understood. We expressed tagged forms of TREHALOSE-6-PHOSPHATE SYNTHASE1 (TPS1) to determine where Tre6P is synthesized in arabidopsis (Arabidopsis thaliana), and investigated the impact of localized changes in Tre6P levels, in axillary buds or vascular tissues, on shoot branching in wild-type and branching mutant backgrounds. TPS1 is expressed in axillary buds and the subtending vasculature, as well as in the leaf and stem vasculature. Expression of a heterologous Tre6P phosphatase (TPP) to lower Tre6P in axillary buds strongly delayed bud outgrowth in long days and inhibited branching in short days. TPP expression in the vasculature also delayed lateral bud outgrowth and decreased branching. Increased Tre6P in the vasculature enhanced branching and was accompanied by higher expression of FLOWERING LOCUS T (FT) and upregulation of sucrose transporters. Increased vascular Tre6P levels enhanced branching in branched1 but not in ft mutant backgrounds. These results provide direct genetic evidence of a local role for Tre6P in regulation of axillary bud outgrowth within the buds themselves, and also connect Tre6P with systemic regulation of shoot branching via FT.},
  language  = {en}
}
@misc{FichtnerBarbierAnnunziataetal.2020,
  author    = {Fichtner, Franziska and Barbier, Francois F. and Annunziata, Maria Grazia and Feil, Regina and Olas, Justyna Jadwiga and M{\"u}ller-R{\"o}ber, Bernd and Stitt, Mark and Beveridge, Christine A. and Lunn, John Edward},
  title     = {Regulation of shoot branching in arabidopsis by trehalose 6-phosphate},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {4},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-56956},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-569564},
  pages     = {19},
  year      = {2020},
  abstract  = {Trehalose 6-phosphate (Tre6P) is a sucrose signalling metabolite that has been implicated in regulation of shoot branching, but its precise role is not understood. We expressed tagged forms of TREHALOSE-6-PHOSPHATE SYNTHASE1 (TPS1) to determine where Tre6P is synthesized in arabidopsis (Arabidopsis thaliana), and investigated the impact of localized changes in Tre6P levels, in axillary buds or vascular tissues, on shoot branching in wild-type and branching mutant backgrounds. TPS1 is expressed in axillary buds and the subtending vasculature, as well as in the leaf and stem vasculature. Expression of a heterologous Tre6P phosphatase (TPP) to lower Tre6P in axillary buds strongly delayed bud outgrowth in long days and inhibited branching in short days. TPP expression in the vasculature also delayed lateral bud outgrowth and decreased branching. Increased Tre6P in the vasculature enhanced branching and was accompanied by higher expression of FLOWERING LOCUS T (FT) and upregulation of sucrose transporters. Increased vascular Tre6P levels enhanced branching in branched1 but not in ft mutant backgrounds. These results provide direct genetic evidence of a local role for Tre6P in regulation of axillary bud outgrowth within the buds themselves, and also connect Tre6P with systemic regulation of shoot branching via FT.},
  language  = {en}
}
@phdthesis{Junker2004,
  author    = {Junker, Bj{\"o}rn H.},
  title     = {Sucrose breakdown in the potato tuber},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0001673},
  school      = {Universit{\"a}t Potsdam},
  year      = {2004},
  abstract  = {In dieser Arbeit wurden verschiedene Ans{\"a}tze verfolgt, um das Verst{\"a}ndnis des Saccharose-zu-St{\"a}rke Stoffwechselweges in sich entwickelnden Kartoffelknollen zu untersuchen. Zun{\"a}chst wurde ein induzierbares Genexpressions-System aus dem Schimmelpilz Aspergillus nidulans f{\"u}r die Untersuchung des Metabolismus von Kartoffelknollen optimiert. Es wurde herausgefunden, dass dieses sogenannte alc system schneller auf Acetaldehyd reagiert als auf Ethanol, und dass Acetaldehyd weniger Seiteneffekte auf den Metabolismus hat. Die optimalen Induktionsbedingungen wurden dann benutzt um die Effekte einer zeitlich kontrollierten zytosolischen Expression einer Hefe-Invertase auf den Metabolismus der Kartoffelknolle zu untersuchen. Die beobachteten Unterschiede zwischen induzierter und konstitutiver Expression der Invertase f{\"u}hrten zu der Feststellung, dass die Glycolyse erst induziert wird nachdem ein ATP-Mangel durch erh{\"o}htes Saccharose-Cycling kreiert wurde. Weiterhin lassen die Ergebnisse darauf schließen, dass Maltose in der Kartoffelknolle eher ein Produkt der Kondensation zweier Glucose-Einheiten ist statt ein Produkt des St{\"a}rke-Abbaus zu sein. Im zweiten Teil dieser Arbeit wurde gezeigt, dass die Expression einer Hefe-Invertase in der Vakuole von Kartoffelknollen {\"a}hnliche Effekte auf deren Metabolismus hat wie die Expression des gleichen Enzymes im Apoplasten. Diese Beobachtung ist ein weiterer Beleg f{\"u}r die Pr{\"a}senz eines Mechanismus, bei dem Saccharose mittels Endozytose in die Vakuole aufgenommen wird anstatt {\"u}ber Transporter direkt ins Zytosol aufgenommen zu werden. Zum Schluß wird ein kinetisches Modell des Saccharose-Abbaus vorgestellt, das in der Lage ist diesen Teil des Stoffwechsels der Kartoffelknolle quantitativ zu simulieren. Weiterhin kann dieses Modell die metabolischen Effekte der Einf{\"u}hrung einer Hefe-Invertase in das Zytosol von Kartoffelknollen mit erstaunlicher Pr{\"a}zision vorhersagen. Zusammengefasst zeigen die Ergebnisse dieser Arbeit, dass induzierbare Genexpression sowie Computermodelle von Stoffwechselwegen n{\"u}tzliche Hilfsmittel f{\"u}r eine Verbesserung des Verst{\"a}ndnisses des Pflanzenmetabolismus sind.},
  language  = {en}
}
@article{MorenoCurtidorAnnunziataGuptaetal.2020,
  author    = {Moreno Curtidor, Catalina and Annunziata, Maria Grazia and Gupta, Saurabh and Apelt, Federico and Richard, Sarah Isabel and Kragler, Friedrich and M{\"u}ller-R{\"o}ber, Bernd and Olas, Justyna Jadwiga},
  title     = {Physiological profiling of embryos and dormant seeds in two Arabidopsis accessions reveals a metabolic switch in carbon reserve accumulation},
  series = {Frontiers in plant science},
  volume    = {11},
  journal   = {Frontiers in plant science},
  publisher = {Frontiers Media},
  address   = {Lausanne},
  issn      = {1664-462X},
  doi       = {10.3389/fpls.2020.588433},
  pages     = {14},
  year      = {2020},
  abstract  = {In flowering plants, sugars act as carbon sources providing energy for developing embryos and seeds. Although most studies focus on carbon metabolism in whole seeds, knowledge about how particular sugars contribute to the developmental transitions during embryogenesis is scarce. To develop a quantitative understanding of how carbon composition changes during embryo development, and to determine how sugar status contributes to final seed or embryo size, we performed metabolic profiling of hand-dissected embryos at late torpedo and mature stages, and dormant seeds, in two Arabidopsis thaliana accessions with medium [Columbia-0 (Col-0)] and large [Burren-0 (Bur-0)] seed sizes, respectively. Our results show that, in both accessions, metabolite profiles of embryos largely differ from those of dormant seeds. We found that developmental transitions from torpedo to mature embryos, and further to dormant seeds, are associated with major metabolic switches in carbon reserve accumulation. While glucose, sucrose, and starch predominantly accumulated during seed dormancy, fructose levels were strongly elevated in mature embryos. Interestingly, Bur-0 seeds contain larger mature embryos than Col-0 seeds. Fructose and starch were accumulated to significantly higher levels in mature Bur-0 than Col-0 embryos, suggesting that they contribute to the enlarged mature Bur-0 embryos. Furthermore, we found that Bur-0 embryos accumulated a higher level of sucrose compared to hexose sugars and that changes in sucrose metabolism are mediated by sucrose synthase (SUS), with SUS genes acting non-redundantly, and in a tissue-specific manner to utilize sucrose during late embryogenesis.},
  language  = {en}
}