1
|
Li X, Ahmad AM, Zhong Y, Ding L, Blennow A, Fettke J. Starch phosphorylation regulates starch granule morphological homogeneity in Arabidopsis thaliana. PLANT PHYSIOLOGY 2024; 194:2600-2615. [PMID: 38060678 PMCID: PMC10980398 DOI: 10.1093/plphys/kiad656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 11/13/2023] [Indexed: 04/01/2024]
Abstract
Starch granule morphological homogeneity presents a gap in starch research. Transitory starch granules in wild-type plants are discoid, regardless of species. Notably, while the shape of starch granules can differ among mutants, it typically remains homogeneous within a genotype. We found an Arabidopsis thaliana mutant, dpe2sex4, lacking both the cytosolic disproportionating enzyme 2 (DPE2) and glucan phosphatase SEX4, showing an unprecedented bimodal starch granule diameter distribution when grown under a light/dark rhythm. dpe2sex4 contained 2 types of starch granules: large granules and small granules. In contrast to the double starch initiation in wheat (Triticum aestivum) endosperm, where A-type granules are initiated first and B-type granules are initiated later, dpe2sex4 small and large granules developed simultaneously in the same chloroplast. Compared with the large granules, the small granules had more branched amylopectin and less surface starch-phosphate, thus having a more compact structure that may hinder starch synthesis. During plant aging, the small granules barely grew. In in vitro experiments, fewer glucosyl residues were incorporated in small granules. Under continuous light, dpe2sex4 starch granules were morphologically homogeneous. Omitting the dark phase after a 2-wk light/dark cycle by moving plants into continuous light also reduced morphological variance between these 2 types of granules. These data shed light on the impact of starch phosphorylation on starch granule morphology homogeneity.
Collapse
Affiliation(s)
- Xiaoping Li
- Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Potsdam-Golm 14776, Germany
| | - Abubakar Musa Ahmad
- Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Potsdam-Golm 14776, Germany
| | - Yuyue Zhong
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg C 1871, Denmark
| | - Li Ding
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg C 1871, Denmark
| | - Andreas Blennow
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg C 1871, Denmark
| | - Joerg Fettke
- Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Potsdam-Golm 14776, Germany
| |
Collapse
|
2
|
Ren X, Chen L, Deng L, Zhao Q, Yao D, Li X, Cong W, Zang Z, Zhao D, Zhang M, Yang S, Zhang J. Comparative transcriptomic analysis reveals the molecular mechanism underlying seedling heterosis and its relationship with hybrid contemporary seeds DNA methylation in soybean. FRONTIERS IN PLANT SCIENCE 2024; 15:1364284. [PMID: 38444535 PMCID: PMC10913200 DOI: 10.3389/fpls.2024.1364284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 01/31/2024] [Indexed: 03/07/2024]
Abstract
Heterosis is widely used in crop production, but phenotypic dominance and its underlying causes in soybeans, a significant grain and oil crop, remain a crucial yet unexplored issue. Here, the phenotypes and transcriptome profiles of three inbred lines and their resulting F1 seedlings were analyzed. The results suggest that F1 seedlings with superior heterosis in leaf size and biomass exhibited a more extensive recompilation in their transcriptional network and activated a greater number of genes compared to the parental lines. Furthermore, the transcriptional reprogramming observed in the four hybrid combinations was primarily non-additive, with dominant effects being more prevalent. Enrichment analysis of sets of differentially expressed genes, coupled with a weighted gene co-expression network analysis, has shown that the emergence of heterosis in seedlings can be attributed to genes related to circadian rhythms, photosynthesis, and starch synthesis. In addition, we combined DNA methylation data from previous immature seeds and observed similar recompilation patterns between DNA methylation and gene expression. We also found significant correlations between methylation levels of gene region and gene expression levels, as well as the discovery of 12 hub genes that shared or conflicted with their remodeling patterns. This suggests that DNA methylation in contemporary hybrid seeds have an impact on both the F1 seedling phenotype and gene expression to some extent. In conclusion, our study provides valuable insights into the molecular mechanisms of heterosis in soybean seedlings and its practical implications for selecting superior soybean varieties.
Collapse
Affiliation(s)
- Xiaobo Ren
- Faculty of Agronomy, Jilin Agricultural University, Changchun, China
| | - Liangyu Chen
- Faculty of Agronomy, Jilin Agricultural University, Changchun, China
- Zhanjiang City Key Laboratory for Tropical Crops Genetic Improvement, South Subtropical Crops Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, China
| | - Lin Deng
- Faculty of Agronomy, Jilin Agricultural University, Changchun, China
| | - Qiuzhu Zhao
- Faculty of Agronomy, Jilin Agricultural University, Changchun, China
| | - Dan Yao
- College of Life Science, Jilin Agricultural University, Changchun, China
| | - Xueying Li
- Faculty of Agronomy, Jilin Agricultural University, Changchun, China
| | - Weixuan Cong
- Faculty of Agronomy, Jilin Agricultural University, Changchun, China
| | - Zhenyuan Zang
- Faculty of Agronomy, Jilin Agricultural University, Changchun, China
| | - Dingyi Zhao
- Faculty of Agronomy, Jilin Agricultural University, Changchun, China
| | - Miao Zhang
- Faculty of Agronomy, Jilin Agricultural University, Changchun, China
| | - Songnan Yang
- Faculty of Agronomy, Jilin Agricultural University, Changchun, China
| | - Jun Zhang
- Faculty of Agronomy, Jilin Agricultural University, Changchun, China
- National Crop Variety Approval and Characteristic Identification Station, Jilin Agricultural University, Changchun, China
| |
Collapse
|
3
|
Sharma M, Abt MR, Eicke S, Ilse TE, Liu C, Lucas MS, Pfister B, Zeeman SC. MFP1 defines the subchloroplast location of starch granule initiation. Proc Natl Acad Sci U S A 2024; 121:e2309666121. [PMID: 38190535 PMCID: PMC10801857 DOI: 10.1073/pnas.2309666121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 12/07/2023] [Indexed: 01/10/2024] Open
Abstract
Starch is one of the major carbohydrate storage compounds in plants. The biogenesis of starch granules starts with the formation of initials, which subsequently expand into granules. Several coiled-coil domain-containing proteins have been previously implicated with the initiation process, but the mechanisms by which they act remain largely elusive. Here, we demonstrate that one of these proteins, the thylakoid-associated MAR-BINDING FILAMENT-LIKE PROTEIN 1 (MFP1), specifically determines the subchloroplast location of initial formation. The expression of MFP1 variants "mis"-targeted to specific locations within chloroplasts in Arabidopsis results in distinctive shifts in not only how many but also where starch granules are formed. Importantly, "re" localizing MFP1 to the stromal face of the chloroplast's inner envelope is sufficient to generate starch granules in this aberrant position. These findings provide compelling evidence that a single protein MFP1 possesses the capacity to direct the initiation and biosynthesis machinery of starch granules.
Collapse
Affiliation(s)
- Mayank Sharma
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Melanie R Abt
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Simona Eicke
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Theresa E Ilse
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Chun Liu
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Miriam S Lucas
- Scientific Center for Optical and Electron Microscopy, ETH Zurich, 8093 Zurich, Switzerland
| | - Barbara Pfister
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - Samuel C Zeeman
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, 8092 Zurich, Switzerland
| |
Collapse
|
4
|
Vandromme C, Spriet C, Putaux JL, Dauvillée D, Courseaux A, D'Hulst C, Wattebled F. Further insight into the involvement of PII1 in starch granule initiation in Arabidopsis leaf chloroplasts. THE NEW PHYTOLOGIST 2023; 239:132-145. [PMID: 37010093 DOI: 10.1111/nph.18923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 03/25/2023] [Indexed: 06/02/2023]
Abstract
The control of starch granule initiation in plant leaves is a complex process that requires active enzymes like Starch Synthase 4 and 3 (SS4 or SS3) and several noncatalytic proteins such as Protein Involved in starch Initiation 1 (PII1). In Arabidopsis leaves, SS4 is the main enzyme that control starch granule initiation, but in its absence, SS3 partly fulfills this function. How these proteins collectively act to control the initiation of starch granules remains elusive. PII1 and SS4 physically interact, and PII1 is required for SS4 to be fully active. However, Arabidopsis mutants lacking SS4 or PII1 still accumulate starch granules. Combining pii1 KO mutation with either ss3 or ss4 KO mutations provide new insights of how the remaining starch granules are synthesized. The ss3 pii1 line still accumulates starch, while the phenotype of ss4 pii1 is stronger than that of ss4. Our results indicate first that SS4 initiates starch granule synthesis in the absence of PII1 albeit being limited to one large lenticular granule per plastid. Second, that if in the absence of SS4, SS3 is able to initiate starch granules with low efficiency, this ability is further reduced with the additional absence of PII1.
Collapse
Affiliation(s)
- Camille Vandromme
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Corentin Spriet
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, US 41 - UAR 2014 - PLBS, F-59000, Lille, France
| | - Jean-Luc Putaux
- Univ. Grenoble Alpes, CNRS, CERMAV, F-38000, Grenoble, France
| | - David Dauvillée
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Adeline Courseaux
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Christophe D'Hulst
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Fabrice Wattebled
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| |
Collapse
|
5
|
Li X, Apriyanto A, Castellanos JF, Compart J, Muntaha SN, Fettke J. 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. FRONTIERS IN PLANT SCIENCE 2022; 13:1039534. [PMID: 36407636 PMCID: PMC9667719 DOI: 10.3389/fpls.2022.1039534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 10/14/2022] [Indexed: 06/16/2023]
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.
Collapse
|
6
|
Ying Y, Xu F, Zhang Z, Tappiban P, Bao J. Dynamic Change in Starch Biosynthetic Enzymes Complexes during Grain-Filling Stages in BEIIb Active and Deficient Rice. Int J Mol Sci 2022; 23:ijms231810714. [PMID: 36142619 PMCID: PMC9501056 DOI: 10.3390/ijms231810714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 09/06/2022] [Accepted: 09/07/2022] [Indexed: 11/16/2022] Open
Abstract
Starch is the predominant reserve in rice (Oryza sativa L.) endosperm, which is synthesized by the coordinated efforts of a series of starch biosynthetic-related enzymes in the form of a multiple enzyme complex. Whether the enzyme complex changes during seed development is not fully understood. Here, we investigated the dynamic change in multi-protein complexes in an indica rice variety IR36 (wild type, WT) and its BEIIb-deficient mutant (be2b) at different developmental stages. Gel permeation chromatography (GPC) and Western blotting analysis of soluble protein fractions revealed most of the enzymes except for SSIVb were eluted in smaller molecular weight fractions at the early developing stage and were transferred to higher molecular weight fractions at the later stage in both WT and be2b. Accordingly, protein interactions were enhanced during seed development as demonstrated by co-immunoprecipitation analysis, suggesting that the enzymes were recruited to form larger protein complexes during starch biosynthesis. The converse elution pattern from GPC of SSIVb may be attributed to its vital role in the initiation step of starch synthesis. The number of protein complexes was markedly decreased in be2b at all development stages. Although SSIVb could partially compensate for the role of BEIIb in protein complex formation, it was hard to form a larger protein complex containing over five proteins in be2b. In addition, other proteins such as PPDKA and PPDKB were possibly present in the multi-enzyme complexes by proteomic analyses of high molecular weight fractions separated from GPC. Two putative protein kinases were found to be potentially associated with starch biosynthetic enzymes. Collectively, our findings unraveled a dynamic change in the protein complex during seed development, and potential roles of BEIIb in starch biosynthesis via various protein complex formations, which enables a deeper understanding of the complex mechanism of starch biosynthesis in rice.
Collapse
Affiliation(s)
- Yining Ying
- Institute of Nuclear Agriculture Science, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
| | - Feifei Xu
- Institute of Nuclear Agriculture Science, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
| | - Zhongwei Zhang
- Institute of Nuclear Agriculture Science, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
| | - Piengtawan Tappiban
- Institute of Nuclear Agriculture Science, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
| | - Jinsong Bao
- Institute of Nuclear Agriculture Science, College of Agriculture and Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
- Hainan Institute of Zhejiang University, Hainan Yazhou Bay Seed Lab, Yazhou Bay Science and Technology City, Yazhou District, Sanya 572025, China
- Correspondence: ; Tel.: +86-571-86971932
| |
Collapse
|
7
|
Muntaha SN, Li X, Compart J, Apriyanto A, Fettke J. Carbon pathways during transitory starch degradation in Arabidopsis differentially affect the starch granule number and morphology in the dpe2/phs1 mutant background. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 180:35-41. [PMID: 35378390 DOI: 10.1016/j.plaphy.2022.03.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/24/2022] [Accepted: 03/26/2022] [Indexed: 06/14/2023]
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.
Collapse
Affiliation(s)
- Sidratul Nur Muntaha
- Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Building 20, Potsdam-Golm, Germany
| | - Xiaoping Li
- Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Building 20, Potsdam-Golm, Germany
| | - Julia Compart
- Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Building 20, Potsdam-Golm, Germany
| | - Ardha Apriyanto
- Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Building 20, Potsdam-Golm, Germany
| | - Joerg Fettke
- Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Building 20, Potsdam-Golm, Germany.
| |
Collapse
|
8
|
Apriyanto A, Compart J, Fettke J. A review of starch, a unique biopolymer - Structure, metabolism and in planta modifications. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 318:111223. [PMID: 35351303 DOI: 10.1016/j.plantsci.2022.111223] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/02/2022] [Accepted: 02/16/2022] [Indexed: 06/14/2023]
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 α-1,4- and α-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.
Collapse
Affiliation(s)
- Ardha Apriyanto
- Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Building 20, 14476 Potsdam-Golm, Germany
| | - Julia Compart
- Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Building 20, 14476 Potsdam-Golm, Germany
| | - Joerg Fettke
- Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Building 20, 14476 Potsdam-Golm, Germany.
| |
Collapse
|
9
|
Figueroa CM, Asencion Diez MD, Ballicora MA, Iglesias AA. Structure, function, and evolution of plant ADP-glucose pyrophosphorylase. PLANT MOLECULAR BIOLOGY 2022; 108:307-323. [PMID: 35006475 DOI: 10.1007/s11103-021-01235-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 12/15/2021] [Indexed: 05/25/2023]
Abstract
This review outlines research performed in the last two decades on the structural, kinetic, regulatory and evolutionary aspects of ADP-glucose pyrophosphorylase, the regulatory enzyme for starch biosynthesis. ADP-glucose pyrophosphorylase (ADP-Glc PPase) catalyzes the first committed step in the pathway of glycogen and starch synthesis in bacteria and plants, respectively. Plant ADP-Glc PPase is a heterotetramer allosterically regulated by metabolites and post-translational modifications. In this review, we focus on the three-dimensional structure of the plant enzyme, the amino acids that bind the regulatory molecules, and the regions involved in transmitting the allosteric signal to the catalytic site. We provide a model for the evolution of the small and large subunits, which produce heterotetramers with distinct catalytic and regulatory properties. Additionally, we review the various post-translational modifications observed in ADP-Glc PPases from different species and tissues. Finally, we discuss the subcellular localization of the enzyme found in grain endosperm from grasses, such as maize and rice. Overall, this work brings together research performed in the last two decades to better understand the multiple mechanisms involved in the regulation of ADP-Glc PPase. The rational modification of this enzyme could improve the yield and resilience of economically important crops, which is particularly important in the current scenario of climate change and food shortage.
Collapse
Affiliation(s)
- Carlos M Figueroa
- Instituto de Agrobiotecnología del Litoral, Universidad Nacional del Litoral, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Bioquímica y Ciencias Biológicas, Santa Fe, Argentina
| | - Matías D Asencion Diez
- Instituto de Agrobiotecnología del Litoral, Universidad Nacional del Litoral, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Bioquímica y Ciencias Biológicas, Santa Fe, Argentina
| | - Miguel A Ballicora
- Department of Chemistry and Biochemistry, Loyola University Chicago, Chicago, IL, USA.
| | - Alberto A Iglesias
- Instituto de Agrobiotecnología del Litoral, Universidad Nacional del Litoral, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Bioquímica y Ciencias Biológicas, Santa Fe, Argentina.
| |
Collapse
|
10
|
Bürgy L, Eicke S, Kopp C, Jenny C, Lu KJ, Escrig S, Meibom A, Zeeman SC. Coalescence and directed anisotropic growth of starch granule initials in subdomains of Arabidopsis thaliana chloroplasts. Nat Commun 2021; 12:6944. [PMID: 34836943 PMCID: PMC8626487 DOI: 10.1038/s41467-021-27151-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 11/01/2021] [Indexed: 12/29/2022] Open
Abstract
Living cells orchestrate enzyme activities to produce myriads of biopolymers but cell-biological understanding of such processes is scarce. Starch, a plant biopolymer forming discrete, semi-crystalline granules within plastids, plays a central role in glucose storage, which is fundamental to life. Combining complementary imaging techniques and Arabidopsis genetics we reveal that, in chloroplasts, multiple starch granules initiate in stromal pockets between thylakoid membranes. These initials coalesce, then grow anisotropically to form lenticular granules. The major starch polymer, amylopectin, is synthesized at the granule surface, while the minor amylose component is deposited internally. The non-enzymatic domain of STARCH SYNTHASE 4, which controls the protein's localization, is required for anisotropic growth. These results present us with a conceptual framework for understanding the biosynthesis of this key nutrient.
Collapse
Affiliation(s)
- Léo Bürgy
- Institute of Molecular Plant Biology, ETH Zurich, 8092, Zurich, Switzerland
| | - Simona Eicke
- Institute of Molecular Plant Biology, ETH Zurich, 8092, Zurich, Switzerland
| | - Christophe Kopp
- Laboratory for Biological Geochemistry, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Camilla Jenny
- Institute of Molecular Plant Biology, ETH Zurich, 8092, Zurich, Switzerland
| | - Kuan Jen Lu
- Institute of Molecular Plant Biology, ETH Zurich, 8092, Zurich, Switzerland
| | - Stephane Escrig
- Laboratory for Biological Geochemistry, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Anders Meibom
- Laboratory for Biological Geochemistry, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Centre for Advanced Surface Analysis, University of Lausanne, Lausanne, Switzerland
| | - Samuel C Zeeman
- Institute of Molecular Plant Biology, ETH Zurich, 8092, Zurich, Switzerland.
| |
Collapse
|
11
|
Mérida A, Fettke J. Starch granule initiation in Arabidopsis thaliana chloroplasts. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:688-697. [PMID: 34051021 DOI: 10.1111/tpj.15359] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/14/2021] [Accepted: 05/22/2021] [Indexed: 06/12/2023]
Abstract
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.
Collapse
Affiliation(s)
- Angel Mérida
- Institute of Plant Biochemistry and Photosynthesis (IBVF), Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Sevilla (US), Avda Américo Vespucio, 49, Sevilla, 41092, Spain
| | - Joerg Fettke
- Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Building 20, Potsdam-Golm, 14476, Germany
| |
Collapse
|
12
|
Hawkins E, Chen J, Watson-Lazowski A, Ahn-Jarvis J, Barclay JE, Fahy B, Hartley M, Warren FJ, Seung D. STARCH SYNTHASE 4 is required for normal starch granule initiation in amyloplasts of wheat endosperm. THE NEW PHYTOLOGIST 2021; 230:2371-2386. [PMID: 33714222 DOI: 10.1111/nph.17342] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 03/05/2021] [Indexed: 05/26/2023]
Abstract
Starch granule initiation is poorly understood at the molecular level. The glucosyltransferase, STARCH SYNTHASE 4 (SS4), plays a central role in granule initiation in Arabidopsis leaves, but its function in cereal endosperms is unknown. We investigated the role of SS4 in wheat, which has a distinct spatiotemporal pattern of granule initiation during grain development. We generated TILLING mutants in tetraploid wheat (Triticum turgidum) that are defective in both SS4 homoeologs. The morphology of endosperm starch was examined in developing and mature grains. SS4 deficiency led to severe alterations in endosperm starch granule morphology. During early grain development, while the wild-type initiated single 'A-type' granules per amyloplast, most amyloplasts in the mutant formed compound granules due to multiple initiations. This phenotype was similar to mutants deficient in B-GRANULE CONTENT 1 (BGC1). SS4 deficiency also reduced starch content in leaves and pollen grains. We propose that SS4 and BGC1 are required for the proper control of granule initiation during early grain development that leads to a single A-type granule per amyloplast. The absence of either protein results in a variable number of initiations per amyloplast and compound granule formation.
Collapse
Affiliation(s)
- Erica Hawkins
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Jiawen Chen
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | | | | | | | - Brendan Fahy
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Matthew Hartley
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | | | - David Seung
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| |
Collapse
|
13
|
Chen J, Hawkins E, Seung D. Towards targeted starch modification in plants. CURRENT OPINION IN PLANT BIOLOGY 2021; 60:102013. [PMID: 33677239 DOI: 10.1016/j.pbi.2021.102013] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 01/23/2021] [Accepted: 01/24/2021] [Indexed: 06/12/2023]
Abstract
Genetic approaches to modify starch in crops have been limited by our knowledge of starch biosynthesis. Recent advances in Arabidopsis have revealed key genetic components determining the size, shape and number of granules in a plastid. This has opened the doors to new discoveries on granule initiation in crop species. In parallel, advances in genomic resources and gene editing technologies allow targeted manipulation of starch biosynthesis genes in isogenic crop backgrounds. Such technologies have been successfully deployed to alter starch composition, and can now be used to modify other starch traits. This will allow the complex relationships between starch structure and physicochemical properties to be elucidated, which will facilitate the rational manipulation of starches in crops.
Collapse
Affiliation(s)
- Jiawen Chen
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Erica Hawkins
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - David Seung
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
| |
Collapse
|
14
|
Compart J, Li X, Fettke J. Starch-A complex and undeciphered biopolymer. JOURNAL OF PLANT PHYSIOLOGY 2021; 258-259:153389. [PMID: 33652172 DOI: 10.1016/j.jplph.2021.153389] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/01/2021] [Accepted: 02/04/2021] [Indexed: 06/12/2023]
Abstract
Starch is a natural storage carbohydrate in plants and algae. It consists of two relatively simple homo-biopolymers, amylopectin and amylose, with only α-1,4 and α-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.
Collapse
Affiliation(s)
- Julia Compart
- Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Building 20, 14476, Potsdam-Golm, Germany
| | - Xiaoping Li
- Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Building 20, 14476, Potsdam-Golm, Germany
| | - Joerg Fettke
- Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Building 20, 14476, Potsdam-Golm, Germany.
| |
Collapse
|
15
|
Tetlow IJ, Bertoft E. A Review of Starch Biosynthesis in Relation to the Building Block-Backbone Model. Int J Mol Sci 2020; 21:E7011. [PMID: 32977627 PMCID: PMC7582286 DOI: 10.3390/ijms21197011] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/15/2020] [Accepted: 09/16/2020] [Indexed: 01/31/2023] Open
Abstract
Starch is a water-insoluble polymer of glucose synthesized as discrete granules inside the stroma of plastids in plant cells. Starch reserves provide a source of carbohydrate for immediate growth and development, and act as long term carbon stores in endosperms and seed tissues for growth of the next generation, making starch of huge agricultural importance. The starch granule has a highly complex hierarchical structure arising from the combined actions of a large array of enzymes as well as physicochemical self-assembly mechanisms. Understanding the precise nature of granule architecture, and how both biological and abiotic factors determine this structure is of both fundamental and practical importance. This review outlines current knowledge of granule architecture and the starch biosynthesis pathway in relation to the building block-backbone model of starch structure. We highlight the gaps in our knowledge in relation to our understanding of the structure and synthesis of starch, and argue that the building block-backbone model takes accurate account of both structural and biochemical data.
Collapse
Affiliation(s)
- Ian J. Tetlow
- Department of Molecular and Cellular Biology, College of Biological Science, University of Guelph, Guelph, ON N1G 2W1, Canada
| | | |
Collapse
|
16
|
Abt MR, Zeeman SC. Evolutionary innovations in starch metabolism. CURRENT OPINION IN PLANT BIOLOGY 2020; 55:109-117. [PMID: 32428846 DOI: 10.1016/j.pbi.2020.03.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/29/2020] [Accepted: 03/02/2020] [Indexed: 05/23/2023]
Abstract
The traditional view of starch metabolism has focused on the multiplicity of enzymes and enzyme isoforms contributing to the production of the constituent polymers, amylopectin and amylose. However, knowledge of these enzymes has not provided a full insight into many aspects of starch biosynthesis. This enzyme-centered view has recently been augmented by the discovery and characterization of novel proteins with proposed regulatory, scaffolding, and interactive roles. This begins to reveal an unprecedented level of complexity beyond mere glucan biosynthesis, enabling us to envisage how starch granules are initiated and grow into specific forms, allowing it to serve biological roles beyond just carbohydrate storage. This review focuses on very recent findings in this vibrant field, highlighting the evolutionary novelty.
Collapse
Affiliation(s)
- Melanie R Abt
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, Universitätstrasse 2, 8092 Zurich, Switzerland
| | - Samuel C Zeeman
- Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, Universitätstrasse 2, 8092 Zurich, Switzerland.
| |
Collapse
|
17
|
Smith AM, Zeeman SC. Starch: A Flexible, Adaptable Carbon Store Coupled to Plant Growth. ANNUAL REVIEW OF PLANT BIOLOGY 2020; 71:217-245. [PMID: 32075407 DOI: 10.1146/annurev-arplant-050718-100241] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Research in the past decade has uncovered new and surprising information about the pathways of starch synthesis and degradation. This includes the discovery of previously unsuspected protein families required both for processes and for the long-sought mechanism of initiation of starch granules. There is also growing recognition of the central role of leaf starch turnover in making carbon available for growth across the day-night cycle. Sophisticated systems-level control mechanisms involving the circadian clock set rates of nighttime starch mobilization that maintain a steady supply of carbon until dawn and modulate partitioning of photosynthate into starch in the light, optimizing the fraction of assimilated carbon that can be used for growth. These discoveries also uncover complexities: Results from experiments with Arabidopsis leaves in conventional controlled environments are not necessarily applicable to other organs or species or to growth in natural, fluctuating environments.
Collapse
Affiliation(s)
| | - Samuel C Zeeman
- Institute of Plant Molecular Biology, ETH Zürich, 8092 Zürich, Switzerland
| |
Collapse
|
18
|
Chia T, Chirico M, King R, Ramirez-Gonzalez R, Saccomanno B, Seung D, Simmonds J, Trick M, Uauy C, Verhoeven T, Trafford K. A carbohydrate-binding protein, B-GRANULE CONTENT 1, influences starch granule size distribution in a dose-dependent manner in polyploid wheat. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:105-115. [PMID: 31633795 DOI: 10.1093/jxb/erz405] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 08/29/2019] [Indexed: 05/19/2023]
Abstract
In Triticeae endosperm (e.g. wheat and barley), starch granules have a bimodal size distribution (with A- and B-type granules) whereas in other grasses the endosperm contains starch granules with a unimodal size distribution. Here, we identify the gene, BGC1 (B-GRANULE CONTENT 1), responsible for B-type starch granule content in Aegilops and wheat. Orthologues of this gene are known to influence starch synthesis in diploids such as rice, Arabidopsis, and barley. However, using polyploid Triticeae species, we uncovered a more complex biological role for BGC1 in starch granule initiation: BGC1 represses the initiation of A-granules in early grain development but promotes the initiation of B-granules in mid grain development. We provide evidence that the influence of BGC1 on starch synthesis is dose dependent and show that three very different starch phenotypes are conditioned by the gene dose of BGC1 in polyploid wheat: normal bimodal starch granule morphology; A-granules with few or no B-granules; or polymorphous starch with few normal A- or B-granules. We conclude from this work that BGC1 participates in controlling B-type starch granule initiation in Triticeae endosperm and that its precise effect on granule size and number varies with gene dose and stage of development.
Collapse
Affiliation(s)
| | | | - Rob King
- Rothamsted Research, West Common, Harpenden, UK
| | | | | | - David Seung
- John Innes Centre, Norwich Research Park, Norwich, UK
| | | | - Martin Trick
- John Innes Centre, Norwich Research Park, Norwich, UK
| | | | | | | |
Collapse
|
19
|
Lloyd JR. The A to B of starch granule formation in wheat endosperm. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:1-3. [PMID: 31841166 PMCID: PMC6913706 DOI: 10.1093/jxb/erz414] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
This article comments on: Chia T, Chirico M, King R et al. 2019. A carbohydrate-binding protein, B-granule content 1 influences starch granule-size distribution in a dose dependent manner in polyploid wheat. Journal of Experimental Botany 70, 105–115.
Collapse
Affiliation(s)
- James R Lloyd
- Department of Genetics, Institute for Plant Biotechnology, University of Stellenbosch, Stellenbosch, South Africa
- Correspondence:
| |
Collapse
|
20
|
Vandromme C, Kasprowicz A, Courseaux A, Trinel D, Facon M, Putaux JL, D’Hulst C, Wattebled F, Spriet C. NegFluo, a Fast and Efficient Method to Determine Starch Granule Size and Morphology In Situ in Plant Chloroplasts. FRONTIERS IN PLANT SCIENCE 2019; 10:1075. [PMID: 31552073 PMCID: PMC6746253 DOI: 10.3389/fpls.2019.01075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 08/07/2019] [Indexed: 06/10/2023]
Abstract
Starch granules that accumulate in the plastids of plants vary in size, shape, phosphate, or protein content according to their botanical origin. Depending on their size, the applications in food and nonfood industries differ. Being able to master starch granule size for a specific plant, without alteration of other characteristics (phosphate content, protein content, etc.), is challenging. The development of a simple and effective screening method to determine the size and shape of starch granules in a plant population is therefore of prime interest. In this study, we propose a new method, NegFluo, that combines negative confocal autofluorescence imaging in leaf and machine learning (ML)-based image analysis. It provides a fast, automated, and easy-to-use pipeline for both in situ starch granule imaging and its morphological analysis. NegFluo was applied to Arabidopsis leaves of wild-type and ss4 mutant plants. We validated its accuracy by comparing morphological quantifications using NegFluo and state-of-the-art methods relying either on starch granule purification or on preparation-intensive electron microscopy combined with manual image analysis. NegFluo thus opens the way to fast in situ analysis of starch granules.
Collapse
Affiliation(s)
- Camille Vandromme
- Univ. Lille, CNRS, UMR8576 – UGSF – Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Angelina Kasprowicz
- Univ. Lille, CNRS, UMR8576 – UGSF – Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Adeline Courseaux
- Univ. Lille, CNRS, UMR8576 – UGSF – Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Dave Trinel
- Univ. Lille, CNRS, UMR8576 – UGSF – Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Maud Facon
- Univ. Lille, CNRS, UMR8576 – UGSF – Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | | | - Christophe D’Hulst
- Univ. Lille, CNRS, UMR8576 – UGSF – Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Fabrice Wattebled
- Univ. Lille, CNRS, UMR8576 – UGSF – Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Corentin Spriet
- Univ. Lille, CNRS, UMR8576 – UGSF – Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| |
Collapse
|
21
|
Cakir B, Tian L, Crofts N, Chou HL, Koper K, Ng CY, Tuncel A, Gargouri M, Hwang SK, Fujita N, Okita TW. Re-programming of gene expression in the CS8 rice line over-expressing ADPglucose pyrophosphorylase induces a suppressor of starch biosynthesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 97:1073-1088. [PMID: 30523657 DOI: 10.1111/tpj.14180] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 11/23/2018] [Accepted: 11/27/2018] [Indexed: 05/02/2023]
Abstract
The CS8 transgenic rice (Oryza sativa L.) lines expressing an up-regulated glgC gene produced higher levels of ADPglucose (ADPglc), the substrate for starch synthases. However, the increase in grain weight was much less than the increase in ADPglc levels suggesting one or more downstream rate-limiting steps. Endosperm starch levels were not further enhanced in double transgenic plants expressing both glgC and the maize brittle-1 gene, the latter responsible for transport of ADPglc into the amyloplast. These studies demonstrate that critical processes within the amyloplast stroma restrict maximum carbon flow into starch. RNA-seq analysis showed extensive re-programming of gene expression in the CS8 with 2073 genes up-regulated and 140 down-regulated. One conspicuous gene, up-regulated ~15-fold, coded for a biochemically uncharacterized starch binding domain-containing protein (SBDCP1) possessing a plastid transit peptide. Confocal microscopy and transmission electron microscopy analysis confirmed that SBDCP1 was located in the amyloplasts. Reciprocal immunoprecipitation and pull-down assays indicated an interaction between SBDCP1 and starch synthase IIIa (SSIIIa), which was down-regulated at the protein level in the CS8 line. Furthermore, binding by SBDCP1 inhibited SSIIIa starch polymerization activity in a non-competitive manner. Surprisingly, artificial microRNA gene suppression of SBDCP1 restored protein expression levels of SSIIIa in the CS8 line resulting in starch with lower amylose content and increased amylopectin chains with a higher degree of polymerization. Collectively, our results support the involvement of additional non-enzymatic factors such as SBDCP in starch biosynthesis.
Collapse
Affiliation(s)
- Bilal Cakir
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA
| | - Li Tian
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA
| | - Naoko Crofts
- Faculty of Bioresource Science, Akita Prefectural University, Shimoshinjo-Nakano, Akita-City, 010-0195, Japan
| | - Hong-Li Chou
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA
| | - Kaan Koper
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA
| | - Chun-Yeung Ng
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA
| | - Aytug Tuncel
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA
| | - Mahmoud Gargouri
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA
| | - Seon-Kap Hwang
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA
| | - Naoko Fujita
- Faculty of Bioresource Science, Akita Prefectural University, Shimoshinjo-Nakano, Akita-City, 010-0195, Japan
| | - Thomas W Okita
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA
| |
Collapse
|
22
|
Findinier J, Laurent S, Duchêne T, Roussel X, Lancelon-Pin C, Cuiné S, Putaux JL, Li-Beisson Y, D'Hulst C, Wattebled F, Dauvillée D. Deletion of BSG1 in Chlamydomonas reinhardtii leads to abnormal starch granule size and morphology. Sci Rep 2019; 9:1990. [PMID: 30760823 PMCID: PMC6374437 DOI: 10.1038/s41598-019-39506-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 01/03/2019] [Indexed: 11/09/2022] Open
Abstract
Chlamydomonas reinhardtii represents an ideal model microbial system to decipher starch metabolism. In this green algae, in cells growing in photosynthetic conditions, starch mainly accumulates as a sheath surrounding the pyrenoid while in cells subjected to a nutrient starvation, numerous starch granules are filling up the plastid stroma. The mechanisms underlying and regulating this switch from photosynthetic to storage starch metabolisms are not known. In this work, we have isolated a Chlamydomonas mutant strain containing a deletion in chromosome 2 which displays abnormal starch granule distribution. Under nitrogen starvation, this strain contains an additional starch granules population. These granules are twice as big as the wild-type granules and display characteristics of photosynthetic starch. Genetic and functional complementation analyses allowed us to identify the gene responsible for this original phenotype which was called BSG1 for "Bimodal Starch Granule". Possible roles of BSG1 in starch metabolism modifications during the transition from photosynthetic to starved growth conditions are discussed.
Collapse
Affiliation(s)
- Justin Findinier
- University Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Sylvain Laurent
- University Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Thierry Duchêne
- University Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Xavier Roussel
- University Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | | | - Stéphan Cuiné
- CEA, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, F-13108, Saint-Paul-lez-Durance, France
| | - Jean-Luc Putaux
- University Grenoble Alpes, CNRS, CERMAV, F-38000, Grenoble, France
| | - Yonghua Li-Beisson
- CEA, Institut de Biologie Environnementale et de Biotechnologie, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, F-13108, Saint-Paul-lez-Durance, France
| | - Christophe D'Hulst
- University Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - Fabrice Wattebled
- University Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France
| | - David Dauvillée
- University Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000, Lille, France.
| |
Collapse
|
23
|
Luo Y, Aoyama S, Fukao Y, Chiba Y, Sato T, Yamaguchi J. Involvement of the membrane-localized ubiquitin ligase ATL8 in sugar starvation response in Arabidopsis. PLANT BIOTECHNOLOGY (TOKYO, JAPAN) 2019; 36:107-112. [PMID: 31768111 PMCID: PMC6847778 DOI: 10.5511/plantbiotechnology.19.0328a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 03/28/2019] [Indexed: 05/11/2023]
Abstract
As major components of the ubiquitin system, ubiquitin ligases mediate the transfer of ubiquitin to specific target substrates, thereby playing important roles in regulating a wide range of cellular processes. The Arabidopsis Tóxicos en Levadura (ATL) family is a group of plant-specific RING-type ubiquitin ligases with N-terminal transmembrane-like domains. To date, 91 ATL isoforms have been identified in the Arabidopsis genome, with some reported to regulate plant responses to environmental stresses. However, the functions of most ATLs remain unclear. This study showed that ATL8 is a sugar starvation response gene and that ATL8 expression was significantly increased by sugar starvation conditions but repressed by exogenous sugar supply. The ATL8 protein was found to possess ubiquitin ligase activity in vitro and to localize to membrane-bound compartments in plant cells. In addition, Starch Synthase 4 was identified as a putative interactor with ATL8, suggesting that ATL8 may be involved in modulating starch accumulation in response to sugar availability. These findings suggest that ATL8 functions as a membrane-localized ubiquitin ligase likely to be involved in the adaptation of Arabidopsis plants to sugar starvation stress.
Collapse
Affiliation(s)
- Yongming Luo
- Faculty of Science and Graduate School of Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Shoki Aoyama
- Faculty of Science and Graduate School of Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Yoichiro Fukao
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Shiga 525-8577, Japan
| | - Yukako Chiba
- Faculty of Science and Graduate School of Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Takeo Sato
- Faculty of Science and Graduate School of Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Junji Yamaguchi
- Faculty of Science and Graduate School of Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| |
Collapse
|