@misc{ApriyantoCompartFettke2022,
  author    = {Apriyanto, Ardha and Compart, Julia and Fettke, J{\"o}rg},
  title     = {A review of starch, a unique biopolymer - structure, metabolism and in planta modifications},
  series = {Plant science : an international journal of experimental plant biology},
  volume    = {318},
  journal   = {Plant science : an international journal of experimental plant biology},
  publisher = {Elsevier Science},
  address   = {Amsterdam [u.a.]},
  issn      = {0168-9452},
  doi       = {10.1016/j.plantsci.2022.111223},
  pages     = {8},
  year      = {2022},
  abstract  = {Starch is a complex carbohydrate polymer produced by plants and especially by crops in huge amounts. It consists of amylose and amylopectin, which have alpha-1,4-and alpha-1,6-linked glucose units. Despite this simple chemistry, the entire starch metabolism is complex, containing various (iso)enzymes/proteins. However, whose interplay is still not yet fully understood. Starch is essential for humans and animals as a source of nutrition and energy. Nowadays, starch is also commonly used in non-food industrial sectors for a variety of purposes. However, native starches do not always satisfy the needs of a wide range of (industrial) applications. This review summarizes the structural properties of starch, analytical methods for starch characterization, and in planta starch modifications.},
  language  = {en}
}
@article{ApriyantoCompartZimmermannetal.2022,
  author    = {Apriyanto, Ardha and Compart, Julia and Zimmermann, Vincent and Alseekh, Saleh and Fernie, Alisdair and Fettke, J{\"o}rg},
  title     = {Indication that starch and sucrose are biomarkers for oil yield in oil palm (Elaeis guineensis Jacq.)},
  series = {Food chemistry},
  volume    = {393},
  journal   = {Food chemistry},
  publisher = {Elsevier},
  address   = {New York, NY [u.a.]},
  issn      = {0308-8146},
  doi       = {10.1016/j.foodchem.2022.133361},
  pages     = {11},
  year      = {2022},
  abstract  = {Oil palm (Elaeis guineensis Jacq.) is the most productive oil-producing crop per hectare of land. The oil that accumulates in the mesocarp tissue of the fruit is the highest observed among fruit-producing plants. A comparative analysis between high-, medium-, and low-yielding oil palms, particularly during fruit development, revealed unique characteristics. Metabolomics analysis was able to distinguish accumulation patterns defining of the various developmental stages and oil yield. Interestingly, high- and medium-yielding oil palms exhibited substantially increased sucrose levels compared to low-yielding palms. In addition, parameters such as starch granule morphology, granule size, total starch content, and starch chain length distribution (CLD) differed significantly among the oil yield categories with a clear correlation between oil yield and various starch parameters. These results provide new insights into carbohydrate and starch metabolism for biosynthesis of oil palm fruits, indicating that starch and sucrose can be used as novel, easy-to-analyze, and reliable biomarker for oil yield.},
  language  = {en}
}
@article{OrzechowskiSitnickaGrabowskaetal.2021,
  author    = {Orzechowski, Slawomir and Sitnicka, Dorota and Grabowska, Agnieszka and Compart, Julia and Fettke, J{\"o}rg and Zdunek-Zastocka, Edyta},
  title     = {Effect of short-term cold treatment on carbohydrate metabolism in potato leaves},
  series = {International journal of molecular sciences},
  volume    = {22},
  journal   = {International journal of molecular sciences},
  number    = {13},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1422-0067},
  doi       = {10.3390/ijms22137203},
  pages     = {17},
  year      = {2021},
  abstract  = {Plants are often challenged by an array of unfavorable environmental conditions. During cold exposure, many changes occur that include, for example, the stabilization of cell membranes, alterations in gene expression and enzyme activities, as well as the accumulation of metabolites. In the presented study, the carbohydrate metabolism was analyzed in the very early response of plants to a low temperature (2 degrees C) in the leaves of 5-week-old potato plants of the Russet Burbank cultivar during the first 12 h of cold treatment (2 h dark and 10 h light). First, some plant stress indicators were examined and it was shown that short-term cold exposure did not significantly affect the relative water content and chlorophyll content (only after 12 h), but caused an increase in malondialdehyde concentration and a decrease in the expression of NDA1, a homolog of the NADH dehydrogenase gene. In addition, it was shown that the content of transitory starch increased transiently in the very early phase of the plant response (3-6 h) to cold treatment, and then its decrease was observed after 12 h. In contrast, soluble sugars such as glucose and fructose were significantly increased only at the end of the light period, where a decrease in sucrose content was observed. The availability of the monosaccharides at constitutively high levels, regardless of the temperature, may delay the response to cold, involving amylolytic starch degradation in chloroplasts. The decrease in starch content, observed in leaves after 12 h of cold exposure, was preceded by a dramatic increase in the transcript levels of the key enzymes of starch degradation initiation, the alpha-glucan, water dikinase (GWD-EC 2.7.9.4) and the phosphoglucan, water dikinase (PWD-EC 2.7.9.5). The gene expression of both dikinases peaked at 9 h of cold exposure, as analyzed by real-time PCR. Moreover, enhanced activities of the acid invertase as well as of both glucan phosphorylases during exposure to a chilling temperature were observed. However, it was also noticed that during the light phase, there was a general increase in glucan phosphorylase activities for both control and cold-stressed plants irrespective of the temperature. In conclusion, a short-term cold treatment alters the carbohydrate metabolism in the leaves of potato, which leads to an increase in the content of soluble sugars.},
  language  = {en}
}
@article{SinghCompartALRawietal.2022,
  author    = {Singh, Aakanksha and Compart, Julia and AL-Rawi, Shadha Abduljaleel and Mahto, Harendra and Ahmad, Abubakar Musa and Fettke, J{\"o}rg},
  title     = {LIKE EARLY STARVATION 1 alters the glucan structures at the starch granule surface and thereby influences the action of both starch-synthesizing and starch-degrading enzymes},
  series = {The plant journal},
  volume    = {111},
  journal   = {The plant journal},
  number    = {3},
  publisher = {Wiley-Blackwell},
  address   = {Oxford},
  issn      = {0960-7412},
  doi       = {10.1111/tpj.15855},
  pages     = {819 -- 835},
  year      = {2022},
  abstract  = {For starch metabolism to take place correctly, various enzymes and proteins acting on the starch granule surface are crucial. Recently, two non-catalytic starch-binding proteins, pivotal for normal starch turnover in Arabidopsis leaves, namely, EARLY STARVATION 1 (ESV1) and its homolog LIKE EARLY STARVATION 1 (LESV), have been identified. Both share nearly 38\% sequence homology. As ESV1 has been found to influence glucan phosphorylation via two starch-related dikinases, alpha-glucan, water dikinase (GWD) and phosphoglucan, water dikinase (PWD), through modulating the surface glucan structures of the starch granules and thus affecting starch degradation, we assess the impact of its homolog LESV on starch metabolism. Thus, the 65-kDa recombinant protein LESV and the 50-kDa ESV1 were analyzed regarding their influence on the action of GWD and PWD on the surface of the starch granules. We included starches from various sources and additionally assessed the effect of these non-enzymatic proteins on other starch-related enzymes, such as starch synthases (SSI and SSIII), starch phosphorylases (PHS1), isoamylase and beta-amylase. The data obtained indicate that starch phosphorylation, hydrolyses and synthesis were affected by LESV and ESV1. Furthermore, incubation with LESV and ESV1 together exerted an additive effect on starch phosphorylation. In addition, a stable alteration of the glucan structures at the starch granule surface following treatment with LESV and ESV1 was observed. Here, we discuss all the observed changes that point to modifications in the glucan structures at the surface of the native starch granules and present a model to explain the existing processes.},
  language  = {en}
}
@misc{LiApriyantoFloresCastellanosetal.2022,
  author    = {Li, Xiaoping and Apriyanto, Ardha and Flores Castellanos, Junio and Compart, Julia and Muntaha, Sidratul Nur and Fettke, J{\"o}rg},
  title     = {Dpe2/phs1 revealed unique starch metabolism with three distinct phases characterized by different starch granule numbers per chloroplast, allowing insights into the control mechanism of granule number regulation by gene co-regulation and metabolic profiling},
  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    = {1286},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-57125},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-571250},
  pages     = {16},
  year      = {2022},
  abstract  = {An Arabidopsis mutant lacking both the cytosolic Disproportionating enzyme 2 (DPE2) and the plastidial glucan Phosphorylase 1 (PHS1) revealed a unique starch metabolism. Dpe2/phs1 has been reported to have only one starch granule number per chloroplast when grown under diurnal rhythm. For this study, we analyzed dpe2/phs1 in details following the mutant development, and found that it showed three distinct periods of granule numbers per chloroplast, while there was no obvious change observed in Col-0. In young plants, the starch granule number was similar to that in Col-0 at first, and then decreased significantly, down to one or no granule per chloroplast, followed by an increase in the granule number. Thus, in dpe2/phs1, control over the starch granule number is impaired, but it is not defective in starch granule initiation. The data also indicate that the granule number is not fixed, and is regulated throughout plant growth. Furthermore, the chloroplasts revealed alterations during these three periods, with a partially strong aberrant morphology in the middle phase. Interestingly, the unique metabolism was perpetuated when starch degradation was further impaired through an additional lack of Isoamylase 3 (ISA3) or Starch excess 4 (SEX4). Transcriptomic studies and metabolic profiling revealed the co-regulation of starch metabolism-related genes and a clear metabolic separation between the periods. Most senescence-induced genes were found to be up-regulated more than twice in the starch-less mature leaves. Thus, dpe2/phs1 is a unique plant material source, with which we may study starch granule number regulation to obtain a more detailed understanding.},
  language  = {en}
}
@article{LiApriyantoFloresCastellanosetal.2022,
  author    = {Li, Xiaoping and Apriyanto, Ardha and Flores Castellanos, Junio and Compart, Julia and Muntaha, Sidratul Nur and Fettke, J{\"o}rg},
  title     = {Dpe2/phs1 revealed unique starch metabolism with three distinct phases characterized by different starch granule numbers per chloroplast, allowing insights into the control mechanism of granule number regulation by gene co-regulation and metabolic profiling},
  series = {Frontiers in Plant Science},
  journal   = {Frontiers in Plant Science},
  publisher = {Frontiers},
  address   = {Lausanne, Schweiz},
  issn      = {1664-462X},
  doi       = {10.3389/fpls.2022.1039534},
  pages     = {1 -- 16},
  year      = {2022},
  abstract  = {An Arabidopsis mutant lacking both the cytosolic Disproportionating enzyme 2 (DPE2) and the plastidial glucan Phosphorylase 1 (PHS1) revealed a unique starch metabolism. Dpe2/phs1 has been reported to have only one starch granule number per chloroplast when grown under diurnal rhythm. For this study, we analyzed dpe2/phs1 in details following the mutant development, and found that it showed three distinct periods of granule numbers per chloroplast, while there was no obvious change observed in Col-0. In young plants, the starch granule number was similar to that in Col-0 at first, and then decreased significantly, down to one or no granule per chloroplast, followed by an increase in the granule number. Thus, in dpe2/phs1, control over the starch granule number is impaired, but it is not defective in starch granule initiation. The data also indicate that the granule number is not fixed, and is regulated throughout plant growth. Furthermore, the chloroplasts revealed alterations during these three periods, with a partially strong aberrant morphology in the middle phase. Interestingly, the unique metabolism was perpetuated when starch degradation was further impaired through an additional lack of Isoamylase 3 (ISA3) or Starch excess 4 (SEX4). Transcriptomic studies and metabolic profiling revealed the co-regulation of starch metabolism-related genes and a clear metabolic separation between the periods. Most senescence-induced genes were found to be up-regulated more than twice in the starch-less mature leaves. Thus, dpe2/phs1 is a unique plant material source, with which we may study starch granule number regulation to obtain a more detailed understanding.},
  language  = {en}
}
@article{CompartLiFettke2021,
  author    = {Compart, Julia and Li, Xiaoping and Fettke, J{\"o}rg},
  title     = {Starch-A complex and undeciphered biopolymer},
  series = {Journal of plant physiology : biochemistry, physiology, molecular biology and biotechnology of plants},
  volume    = {258},
  journal   = {Journal of plant physiology : biochemistry, physiology, molecular biology and biotechnology of plants},
  publisher = {Elsevier},
  address   = {M{\"u}nchen},
  issn      = {0176-1617},
  doi       = {10.1016/j.jplph.2021.153389},
  pages     = {258 -- 259},
  year      = {2021},
  abstract  = {Starch is a natural storage carbohydrate in plants and algae. It consists of two relatively simple homo-biopolymers, amylopectin and amylose, with only alpha-1,4 and alpha-1,6 linked glucosyl units. Starch is an essential source of nutrition and animal food, as well as an important raw material for industry. However, despite increasing knowledge, detailed information about its structure and turnover are largely lacking. In the last decades, most data were generated using bulk experiments, a method which obviously presents limitations regarding a deeper understanding of the starch metabolism. Here, we discuss some unavoidable questions arising from the existing data. We focus on a few examples related to starch biosynthesis, degradation, and structure where these limitations strongly emerge. Closing these knowledge gaps will also be extremely important for taking the necessary steps in order to set up starch-providing crops for the challenges of the ongoing climate changes, as well as for increasing the usability of starches for industrial applications by biotechnology.},
  language  = {en}
}
@article{MuntahaLiCompartetal.2022,
  author    = {Muntaha, Sidratul Nur and Li, Xiaoping and Compart, Julia and Apriyanto, Ardha and Fettke, J{\"o}rg},
  title     = {Carbon pathways during transitory starch degradation in Arabidopsis differentially affect the starch granule number and morphology in the dpe2/phs1 mutant background},
  series = {Plant physiology and biochemistry : an official journal of the Federation of European Societies of Plant Physiology},
  volume    = {180},
  journal   = {Plant physiology and biochemistry : an official journal of the Federation of European Societies of Plant Physiology},
  publisher = {Elsevier},
  address   = {Paris},
  issn      = {0981-9428},
  doi       = {10.1016/j.plaphy.2022.03.033},
  pages     = {35 -- 41},
  year      = {2022},
  abstract  = {The Arabidopsis knockout mutant lacking both the cytosolic disproportionating enzyme 2 (DPE2) and the plastidial phosphorylase (PHS1) had a dwarf-growth phenotype, a reduced and uneven distribution of starch within the plant rosettes, and a lower starch granule number per chloroplast under standard growth conditions. In contrast, a triple mutant impaired in starch degradation by its additional lack of the glucan, water dikinase (GWD) showed improved plant growth, a starch-excess phenotype, and a homogeneous starch distribution. Furthermore, the number of starch granules per chloroplast was increased and was similar to the wild type. We concluded that ongoing starch degradation is mainly responsible for the observed phenotype of dpe2/phs1. Next, we generated two further triple mutants lacking either the phosphoglucan, water dikinase (PWD), or the disproportionating enzyme 1 (DPE1) in the background of the double mutant. Analysis of the starch metabolism revealed that even minor ongoing starch degradation observed in dpe2/phs1/pwd maintained the double mutant phenotype. In contrast, an additional blockage in the glucose pathway of starch breakdown, as in dpe2/phs1/ dpe1, resulted in a nearly starch-free phenotype and massive chloroplast degradation. The characterized mutants were discussed in the context of starch granule formation.},
  language  = {en}
}