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 - Merida, Angel A1 - Fettke, Jörg T1 - Starch granule initiation in Arabidopsis thaliana chloroplasts JF - The plant journal N2 - The initiation of starch granule formation and the mechanism controlling the number of granules per plastid have been some of the most elusive aspects of starch metabolism. This review covers the advances made in the study of these processes. The analyses presented herein depict a scenario in which starch synthase isoform 4 (SS4) provides the elongating activity necessary for the initiation of starch granule formation. However, this protein does not act alone; other polypeptides are required for the initiation of an appropriate number of starch granules per chloroplast. The functions of this group of polypeptides include providing suitable substrates (maltooligosaccharides) to SS4, the localization of the starch initiation machinery to the thylakoid membranes, and facilitating the correct folding of SS4. The number of starch granules per chloroplast is tightly regulated and depends on the developmental stage of the leaves and their metabolic status. Plastidial phosphorylase (PHS1) and other enzymes play an essential role in this process since they are necessary for the synthesis of the substrates used by the initiation machinery. The mechanism of starch granule formation initiation in Arabidopsis seems to be generalizable to other plants and also to the synthesis of long-term storage starch. The latter, however, shows specific features due to the presence of more isoforms, the absence of constantly recurring starch synthesis and degradation, and the metabolic characteristics of the storage sink organs. KW - starch granules KW - starch metabolism KW - starch granule initiation KW - starch KW - granule number per chloroplast KW - starch morphology KW - Arabidopsis thaliana Y1 - 2021 U6 - https://doi.org/10.1111/tpj.15359 SN - 0960-7412 SN - 1365-313X VL - 107 IS - 3 SP - 688 EP - 697 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Fettke, Jörg A1 - Leifels, Lydia A1 - Brust, Henrike A1 - Herbst, Karoline A1 - Steup, Martin T1 - Two carbon fluxes to reserve starch in potato (Solanum tuberosum L.) tuber cells are closely interconnected but differently modulated by temperature JF - Journal of experimental botany N2 - Parenchyma cells from tubers of Solanum tuberosum L. convert several externally supplied sugars to starch but the rates vary largely. Conversion of glucose 1-phosphate to starch is exceptionally efficient. In this communication, tuber slices were incubated with either of four solutions containing equimolar [U-C-14]glucose 1-phosphate, [U-C-14]sucrose, [U-C-14]glucose 1-phosphate plus unlabelled equimolar sucrose or [U-C-14]sucrose plus unlabelled equimolar glucose 1-phosphate. C-14-incorporation into starch was monitored. In slices from freshly harvested tubers each unlabelled compound strongly enhanced C-14 incorporation into starch indicating closely interacting paths of starch biosynthesis. However, enhancement disappeared when the tubers were stored. The two paths (and, consequently, the mutual enhancement effect) differ in temperature dependence. At lower temperatures, the glucose 1-phosphate-dependent path is functional, reaching maximal activity at approximately 20 degrees C but the flux of the sucrose-dependent route strongly increases above 20 degrees C. Results are confirmed by in vitro experiments using [U-C-14]glucose 1-phosphate or adenosine-[U-C-14]glucose and by quantitative zymograms of starch synthase or phosphorylase activity. In mutants almost completely lacking the plastidial phosphorylase isozyme(s), the glucose 1-phosphate-dependent path is largely impeded. Irrespective of the size of the granules, glucose 1-phosphate-dependent incorporation per granule surface area is essentially equal. Furthermore, within the granules no preference of distinct glucosyl acceptor sites was detectable. Thus, the path is integrated into the entire granule biosynthesis. In vitro C-14-incorporation into starch granules mediated by the recombinant plastidial phosphorylase isozyme clearly differed from the in situ results. Taken together, the data clearly demonstrate that two closely but flexibly interacting general paths of starch biosynthesis are functional in potato tuber cells. KW - glucose 1-phosphate KW - phosphorylase KW - potato tubers KW - starch KW - starch synthase Y1 - 2012 U6 - https://doi.org/10.1093/jxb/ers014 SN - 0022-0957 VL - 63 IS - 8 SP - 3011 EP - 3029 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Compart, Julia A1 - Singh, Aakanksha A1 - Fettke, Jörg A1 - Apriyanto, Ardha T1 - Customizing starch properties BT - a review of starch modifications and their applications JF - Polymers N2 - Starch has been a convenient, economically important polymer with substantial applications in the food and processing industry. However, native starches present restricted applications, which hinder their industrial usage. Therefore, modification of starch is carried out to augment the positive characteristics and eliminate the limitations of the native starches. Modifications of starch can result in generating novel polymers with numerous functional and value-added properties that suit the needs of the industry. Here, we summarize the possible starch modifications in planta and outside the plant system (physical, chemical, and enzymatic) and their corresponding applications. In addition, this review will highlight the implications of each starch property adjustment. KW - starch KW - starch modification KW - in planta modification KW - physical modification KW - chemical modification KW - enzymatic modification KW - starch application Y1 - 2023 U6 - https://doi.org/10.3390/polym15163491 SN - 2073-4360 VL - 15 IS - 16 PB - MDPI CY - Basel ER - TY - JOUR A1 - Brust, Henrike A1 - Orzechowski, Slawomir A1 - Fettke, Jörg T1 - Starch and Glycogen Analyses BT - Methods and Techniques JF - Biomolecules N2 - For complex carbohydrates, such as glycogen and starch, various analytical methods and techniques exist allowing the detailed characterization of these storage carbohydrates. In this article, we give a brief overview of the most frequently used methods, techniques, and results. Furthermore, we give insights in the isolation, purification, and fragmentation of both starch and glycogen. An overview of the different structural levels of the glucans is given and the corresponding analytical techniques are discussed. Moreover, future perspectives of the analytical needs and the challenges of the currently developing scientific questions are included KW - starch KW - glycogen KW - analytics Y1 - 2020 U6 - https://doi.org/10.3390/biom10071020 SN - 2218-273X VL - 10 IS - 7 PB - MDPI CY - Basel ER - TY - JOUR A1 - Apriyanto, Ardha A1 - Compart, Julia A1 - Zimmermann, Vincent A1 - Alseekh, Saleh A1 - Fernie, Alisdair A1 - Fettke, Jörg T1 - Indication that starch and sucrose are biomarkers for oil yield in oil palm (Elaeis guineensis Jacq.) JF - Food chemistry N2 - 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. KW - carbohydrate KW - mesocarp KW - metabolites KW - oil palm KW - oil yield KW - sucrose; KW - starch Y1 - 2022 U6 - https://doi.org/10.1016/j.foodchem.2022.133361 SN - 0308-8146 SN - 1873-7072 VL - 393 PB - Elsevier CY - New York, NY [u.a.] ER - TY - JOUR A1 - Apriyanto, Ardha A1 - Compart, Julia A1 - Fettke, Jörg T1 - Transcriptomic analysis of mesocarp tissue during fruit development of the oil palm revealed specific isozymes related to starch metabolism that control oil yield JF - Frontiers in plant science N2 - The oil palm (Elaeis guineensis Jacq.) produces a large amount of oil from the fruit. However, increasing the oil production in this fruit is still challenging. A recent study has shown that starch metabolism is essential for oil synthesis in fruit-producing species. Therefore, the transcriptomic analysis by RNA-seq was performed to observe gene expression alteration related to starch metabolism genes throughout the maturity stages of oil palm fruit with different oil yields. Gene expression profiles were examined with three different oil yields group (low, medium, and high) at six fruit development phases (4, 8, 12, 16, 20, and 22 weeks after pollination). We successfully identified and analyzed differentially expressed genes in oil palm mesocarps during development. The results showed that the transcriptome profile for each developmental phase was unique. Sucrose flux to the mesocarp tissue, rapid starch turnover, and high glycolytic activity have been identified as critical factors for oil production in oil palms. For starch metabolism and the glycolytic pathway, we identified specific gene expressions of enzyme isoforms (isozymes) that correlated with oil production, which may determine the oil content. This study provides valuable information for creating new high-oil-yielding palm varieties via breeding programs or genome editing approaches. KW - starch KW - oil yield KW - fruit development KW - gene expression KW - RNA-seq KW - and palm KW - oil KW - Elaeis guineensis Jacq Y1 - 2023 U6 - https://doi.org/10.3389/fpls.2023.1220237 SN - 1664-462X VL - 14 PB - Frontiers Media CY - Lausanne ER -