TY - JOUR A1 - Liu, Qingting A1 - Li, Xiaoping A1 - Fettke, Jörg T1 - Starch granules in Arabidopsis thaliana mesophyll and guard cells show similar morphology but differences in size and number JF - International journal of molecular sciences N2 - Transitory starch granules result from complex carbon turnover and display specific situations during starch synthesis and degradation. The fundamental mechanisms that specify starch granule characteristics, such as granule size, morphology, and the number per chloroplast, are largely unknown. However, transitory starch is found in the various cells of the leaves of Arabidopsis thaliana, but comparative analyses are lacking. Here, we adopted a fast method of laser confocal scanning microscopy to analyze the starch granules in a series of Arabidopsis mutants with altered starch metabolism. This allowed us to separately analyze the starch particles in the mesophyll and in guard cells. In all mutants, the guard cells were always found to contain more but smaller plastidial starch granules than mesophyll cells. The morphological properties of the starch granules, however, were indiscernible or identical in both types of leaf cells. KW - starch granules KW - starch granule number per chloroplast KW - starch morphology KW - mesophyll cell KW - guard cell KW - LCSM KW - Arabidopsis thaliana KW - starch granule initiation KW - starch metabolism Y1 - 2021 U6 - https://doi.org/10.3390/ijms22115666 SN - 1422-0067 SN - 1661-6596 VL - 22 IS - 11 PB - Molecular Diversity Preservation International CY - Basel ER - TY - GEN A1 - Liu, Qingting A1 - Li, Xiaoping A1 - Fettke, Jörg T1 - Starch granules in Arabidopsis thaliana mesophyll and guard cells show similar morphology but differences in size and number T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Transitory starch granules result from complex carbon turnover and display specific situations during starch synthesis and degradation. The fundamental mechanisms that specify starch granule characteristics, such as granule size, morphology, and the number per chloroplast, are largely unknown. However, transitory starch is found in the various cells of the leaves of Arabidopsis thaliana, but comparative analyses are lacking. Here, we adopted a fast method of laser confocal scanning microscopy to analyze the starch granules in a series of Arabidopsis mutants with altered starch metabolism. This allowed us to separately analyze the starch particles in the mesophyll and in guard cells. In all mutants, the guard cells were always found to contain more but smaller plastidial starch granules than mesophyll cells. The morphological properties of the starch granules, however, were indiscernible or identical in both types of leaf cells. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1143 KW - starch granules KW - starch metabolism KW - starch granule initiation KW - starch granule number per chloroplast KW - starch morphology KW - mesophyll cell KW - guard cell KW - LCSM KW - Arabidopsis thaliana Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-511067 SN - 1866-8372 IS - 1143 ER - TY - JOUR A1 - Apriyanto, Ardha A1 - Compart, Julia A1 - Fettke, Jörg T1 - A review of starch, a unique biopolymer - structure, metabolism and in planta modifications JF - Plant science : an international journal of experimental plant biology N2 - 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. KW - starch KW - starch structure KW - starch surface KW - starch modifications; KW - analytics Y1 - 2022 U6 - https://doi.org/10.1016/j.plantsci.2022.111223 SN - 0168-9452 SN - 1873-2259 VL - 318 PB - Elsevier Science CY - Amsterdam [u.a.] ER - TY - GEN A1 - Liu, Qingting A1 - Zhou, Yuan A1 - Fettke, Jörg T1 - Starch granule size and morphology of Arabidopsis thaliana starch-related mutants analyzed during diurnal rhythm and development T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Transitory starch plays a central role in the life cycle of plants. Many aspects of this important metabolism remain unknown; however, starch granules provide insight into this persistent metabolic process. Therefore, monitoring alterations in starch granules with high temporal resolution provides one significant avenue to improve understanding. Here, a previously established method that combines LCSM and safranin-O staining for in vivo imaging of transitory starch granules in leaves of Arabidopsis thaliana was employed to demonstrate, for the first time, the alterations in starch granule size and morphology that occur both throughout the day and during leaf aging. Several starch-related mutants were included, which revealed differences among the generated granules. In ptst2 and sex1-8, the starch granules in old leaves were much larger than those in young leaves; however, the typical flattened discoid morphology was maintained. In ss4 and dpe2/phs1/ss4, the morphology of starch granules in young leaves was altered, with a more rounded shape observed. With leaf development, the starch granules became spherical exclusively in dpe2/phs1/ss4. Thus, the presented data provide new insights to contribute to the understanding of starch granule morphogenesis. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1245 KW - starch metabolism KW - starch granule KW - starch granule size KW - starch granule morphology KW - LCSM KW - Arabidopsis thaliana Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-550291 SN - 1866-8372 VL - 26 SP - 1 EP - 9 PB - Universitätsverlag Potsdam CY - Potsdam ET - 19 ER - TY - JOUR A1 - Liu, Qingting A1 - Zhou, Yuan A1 - Fettke, Jörg T1 - Starch granule size and morphology of Arabidopsis thaliana starch-related mutants analyzed during diurnal rhythm and development JF - Molecules : a journal of synthetic chemistry and natural product chemistry / Molecular Diversity Preservation International N2 - Transitory starch plays a central role in the life cycle of plants. Many aspects of this important metabolism remain unknown; however, starch granules provide insight into this persistent metabolic process. Therefore, monitoring alterations in starch granules with high temporal resolution provides one significant avenue to improve understanding. Here, a previously established method that combines LCSM and safranin-O staining for in vivo imaging of transitory starch granules in leaves of Arabidopsis thaliana was employed to demonstrate, for the first time, the alterations in starch granule size and morphology that occur both throughout the day and during leaf aging. Several starch-related mutants were included, which revealed differences among the generated granules. In ptst2 and sex1-8, the starch granules in old leaves were much larger than those in young leaves; however, the typical flattened discoid morphology was maintained. In ss4 and dpe2/phs1/ss4, the morphology of starch granules in young leaves was altered, with a more rounded shape observed. With leaf development, the starch granules became spherical exclusively in dpe2/phs1/ss4. Thus, the presented data provide new insights to contribute to the understanding of starch granule morphogenesis. KW - starch metabolism KW - starch granule KW - starch granule size KW - starch granule morphology KW - LCSM KW - Arabidopsis thaliana Y1 - 2021 U6 - https://doi.org/10.3390/molecules26195859 SN - 1420-3049 VL - 26 SP - 1 EP - 9 PB - MDPI CY - Basel, Schweiz ET - 19 ER - TY - JOUR A1 - Malinova, Irina A1 - Kössler, Stella A1 - Orawetz, Tom A1 - Matthes, Ulrike A1 - Orzechowski, Slawomir A1 - Koch, Anke A1 - Fettke, Jörg T1 - Identification of two Arabidopsis thaliana plasma membrane transporters able to transport glucose 1-phosphate JF - Plant & cell physiology N2 - Primary carbohydrate metabolism in plants includes several sugar and sugar-derivative transport processes. Over recent years, evidences have shown that in starch-related transport processes, in addition to glucose 6-phosphate, maltose, glucose and triose-phosphates, glucose 1-phosphate also plays a role and thereby increases the possible fluxes of sugar metabolites in planta. In this study, we report the characterization of two highly similar transporters, At1g34020 and At4g09810, in Arabidopsis thaliana, which allow the import of glucose 1-phosphate through the plasma membrane. Both transporters were expressed in yeast and were biochemically analyzed to reveal an antiport of glucose 1-phosphate/phosphate. Furthermore, we showed that the apoplast of Arabidopsis leaves contained glucose 1-phosphate and that the corresponding mutant of these transporters had higher glucose 1-phosphate amounts in the apoplast and alterations in starch and starch-related metabolism. KW - apoplast KW - Arabidopsis thaliana KW - glucose 1-phosphate transport KW - starch metabolism KW - sugar transport Y1 - 2020 U6 - https://doi.org/10.1093/pcp/pcz206 SN - 0032-0781 SN - 1471-9053 VL - 61 IS - 2 SP - 381 EP - 392 PB - Oxford University Press CY - Oxford ER - TY - JOUR A1 - Compart, Julia A1 - Li, Xiaoping A1 - Fettke, Jörg T1 - Starch-A complex and undeciphered biopolymer JF - Journal of plant physiology : biochemistry, physiology, molecular biology and biotechnology of plants N2 - 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. KW - Starch KW - Starch structure KW - Organization model KW - Starch metabolism KW - Analytical limitations Y1 - 2021 U6 - https://doi.org/10.1016/j.jplph.2021.153389 SN - 0176-1617 SN - 1618-1328 VL - 258 SP - 258 EP - 259 PB - Elsevier CY - München ER - TY - JOUR A1 - Singh, Aakanksha A1 - Compart, Julia A1 - AL-Rawi, Shadha Abduljaleel A1 - Mahto, Harendra A1 - Ahmad, Abubakar Musa A1 - Fettke, Jörg T1 - 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 JF - The plant journal N2 - 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. KW - starch KW - starch metabolism KW - starch surface structure KW - Arabidopsis KW - thaliana Y1 - 2022 U6 - https://doi.org/10.1111/tpj.15855 SN - 0960-7412 SN - 1365-313X VL - 111 IS - 3 SP - 819 EP - 835 PB - Wiley-Blackwell CY - Oxford ER - TY - JOUR A1 - Li, Xiaoping A1 - Apriyanto, Ardha A1 - Flores Castellanos, Junio A1 - Compart, Julia A1 - Muntaha, Sidratul Nur A1 - Fettke, Jörg T1 - 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 JF - Frontiers in Plant Science N2 - 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. KW - LCSM KW - RNA-Seq KW - metabolic-profiling KW - starch granule number regulation KW - starch initiation KW - starch degradation Y1 - 2022 U6 - https://doi.org/10.3389/fpls.2022.1039534 SN - 1664-462X SP - 1 EP - 16 PB - Frontiers CY - Lausanne, Schweiz ER - TY - JOUR A1 - Orzechowski, Slawomir A1 - Sitnicka, Dorota A1 - Grabowska, Agnieszka A1 - Compart, Julia A1 - Fettke, Jörg A1 - Zdunek-Zastocka, Edyta T1 - Effect of short-term cold treatment on carbohydrate metabolism in potato leaves JF - International journal of molecular sciences N2 - 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. KW - cold stress KW - alpha-glucan KW - water dikinase KW - phosphoglucan water dikinase KW - chloroplast isolation KW - glucan phosphorylase KW - acid invertase Y1 - 2021 U6 - https://doi.org/10.3390/ijms22137203 SN - 1422-0067 VL - 22 IS - 13 PB - MDPI CY - Basel ER -