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Liu Y, Xi W, Wang X, Li H, Liu H, Li T, Hou J, Liu X, Hao C, Zhang X. TabHLH95-TaNF-YB1 module promotes grain starch synthesis in bread wheat. J Genet Genomics 2023; 50:883-894. [PMID: 37062449 DOI: 10.1016/j.jgg.2023.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 04/03/2023] [Accepted: 04/06/2023] [Indexed: 04/18/2023]
Abstract
Starch is the most abundant substance in wheat (Triticum aestivum L.) endosperm and provides the major carbohydrate energy for human daily life. Starch synthesis-related (SSR) genes are believed to be spatiotemporally specific, but their transcriptional regulation remains unclear in wheat. Here, we investigate the role of the basic helix-loop-helix (bHLH) transcription factor TabHLH95 in starch synthesis. TabHLH95 is preferentially expressed in the developing grains in wheat and encodes a nucleus localized protein without autoactivation activity. The Tabhlh95 knockout mutants display smaller grain size and less starch content than wild type, whereas overexpression of TabHLH95 enhances starch accumulation and significantly improves thousand grain weight. Transcriptome analysis reveals that the expression of multiple SSR genes is significantly reduced in the Tabhlh95 mutants. TabHLH95 binds to the promoters of ADP-glucose pyrophosphorylase large subunit 1 (AGPL1-1D/-1B), AGPL2-5D, and isoamylase (ISA1-7D) and enhances their transcription. Intriguingly, TabHLH95 interacts with the nuclear factor Y (NF-Y) family transcription factor TaNF-YB1, thereby synergistically regulating starch synthesis. These results suggest that the TabHLH95-TaNF-YB1 complex positively modulates starch synthesis and grain weight by regulating the expression of a subset of SSR genes, thus providing a good potential approach for genetic improvement of grain productivity in wheat.
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Affiliation(s)
- Yunchuan Liu
- Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture and Rural Affairs/The National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Wei Xi
- Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture and Rural Affairs/The National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China; State Key Laboratory of Aridland Crop Science (Gansu Agricultural University)/Gansu Provincial Key Laboratory of Crop Improvement & Germplasm Enhancement, Lanzhou, Gansu 730070, China; College of Agronomy, Gansu Agricultural University, Lanzhou, Gansu 730070, China
| | - Xiaolu Wang
- Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture and Rural Affairs/The National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Huifang Li
- Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture and Rural Affairs/The National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Hongxia Liu
- Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture and Rural Affairs/The National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Tian Li
- Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture and Rural Affairs/The National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jian Hou
- Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture and Rural Affairs/The National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xu Liu
- Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture and Rural Affairs/The National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
| | - Chenyang Hao
- Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture and Rural Affairs/The National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
| | - Xueyong Zhang
- Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture and Rural Affairs/The National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
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2
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Boehlein SK, Pfister B, Hennen-Bierwagen TA, Liu C, Ritter M, Hannah LC, Zeeman SC, Resende MFR, Myers AM. Soluble and insoluble α-glucan synthesis in yeast by enzyme suites derived exclusively from maize endosperm. PLANT PHYSIOLOGY 2023; 193:1456-1478. [PMID: 37339339 PMCID: PMC10517254 DOI: 10.1093/plphys/kiad358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 04/28/2023] [Accepted: 05/23/2023] [Indexed: 06/22/2023]
Abstract
Molecular mechanisms that distinguish the synthesis of semi-crystalline α-glucan polymers found in plant starch granules from the synthesis of water-soluble polymers by nonplant species are not well understood. To address this, starch biosynthetic enzymes from maize (Zea mays L.) endosperm were isolated in a reconstituted environment using yeast (Saccharomyces cerevisiae) as a test bed. Ninety strains were constructed containing unique combinations of 11 synthetic transcription units specifying maize starch synthase (SS), starch phosphorylase (PHO), starch branching enzyme (SBE), or isoamylase-type starch debranching enzyme (ISA). Soluble and insoluble branched α-glucans accumulated in varying proportions depending on the enzyme suite, with ISA function stimulating distribution into the insoluble form. Among the SS isoforms, SSIIa, SSIII, and SSIV individually supported the accumulation of glucan polymer. Neither SSI nor SSV alone produced polymers; however, synergistic effects demonstrated that both isoforms can stimulate α-glucan accumulation. PHO did not support α-glucan production by itself, but it had either positive or negative effects on polymer content depending on which SS or a combination thereof was present. The complete suite of maize enzymes generated insoluble particles resembling native starch granules in size, shape, and crystallinity. Ultrastructural analysis revealed a hierarchical assembly starting with subparticles of approximately 50 nm diameter that coalesce into discrete structures of approximately 200 nm diameter. These are assembled into semi-crystalline α-glucan superstructures up to 4 μm in length filling most of the yeast cytosol. ISA was not essential for the formation of such particles, but their abundance was increased dramatically by ISA presence.
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Affiliation(s)
- Susan K Boehlein
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32601, USA
| | - Barbara Pfister
- Institute of Molecular Plant Biology, ETH Zurich, Zurich 8092, Switzerland
| | - Tracie A Hennen-Bierwagen
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Chun Liu
- Institute of Molecular Plant Biology, ETH Zurich, Zurich 8092, Switzerland
| | - Maximilian Ritter
- Institute for Building Materials, Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Zurich 8093, Switzerland
| | - L Curtis Hannah
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32601, USA
| | - Samuel C Zeeman
- Institute of Molecular Plant Biology, ETH Zurich, Zurich 8092, Switzerland
| | - Marcio F R Resende
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32601, USA
| | - Alan M Myers
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
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3
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Chen J, Watson-Lazowski A, Kamble NU, Vickers M, Seung D. Gene expression profile of the developing endosperm in durum wheat provides insight into starch biosynthesis. BMC PLANT BIOLOGY 2023; 23:363. [PMID: 37460981 DOI: 10.1186/s12870-023-04369-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 07/11/2023] [Indexed: 07/20/2023]
Abstract
BACKGROUND Durum wheat (Triticum turgidum subsp. durum) is widely grown for pasta production, and more recently, is gaining additional interest due to its resilience to warm, dry climates and its use as an experimental model for wheat research. Like in bread wheat, the starch and protein accumulated in the endosperm during grain development are the primary contributors to the calorific value of durum grains. RESULTS To enable further research into endosperm development and storage reserve synthesis, we generated a high-quality transcriptomics dataset from developing endosperms of variety Kronos, to complement the extensive mutant resources available for this variety. Endosperms were dissected from grains harvested at eight timepoints during grain development (6 to 30 days post anthesis (dpa)), then RNA sequencing was used to profile the transcriptome at each stage. The largest changes in gene expression profile were observed between the earlier timepoints, prior to 15 dpa. We detected a total of 29,925 genes that were significantly differentially expressed between at least two timepoints, and clustering analysis revealed nine distinct expression patterns. We demonstrate the potential of our dataset to provide new insights into key processes that occur during endosperm development, using starch metabolism as an example. CONCLUSION We provide a valuable resource for studying endosperm development in this increasingly important crop species.
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Affiliation(s)
- Jiawen Chen
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Alexander Watson-Lazowski
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
- Harper Adams University, Newport, Shropshire, TF10 8NB, UK
| | | | - Martin Vickers
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - David Seung
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
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4
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Kang X, Gao W, Cui B, El-Aty AMA. Structure and genetic regulation of starch formation in sorghum (Sorghum bicolor (L.) Moench) endosperm: A review. Int J Biol Macromol 2023; 239:124315. [PMID: 37023877 DOI: 10.1016/j.ijbiomac.2023.124315] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 03/27/2023] [Accepted: 03/30/2023] [Indexed: 04/08/2023]
Abstract
This review focuses on the structure and genetic regulation of starch formation in sorghum (Sorghum bicolor (L.) Moench) endosperm. Sorghum is an important cereal crop that is well suited to grow in regions with high temperatures and limited water resources due to its C4 metabolism. The endosperm of sorghum kernels is a rich source of starch, which is composed of two main components: amylose and amylopectin. The synthesis of starch in sorghum endosperm involves multiple enzymatic reactions, which are regulated by complex genetic and environmental factors. Recent research has identified several genes involved in the regulation of starch synthesis in sorghum endosperm. In addition, the structure and properties of sorghum starch can also be influenced by environmental factors such as temperature, water availability, and soil nutrients. A better understanding of the structure and genetic regulation of starch formation in sorghum endosperm can have important implications for the development of sorghum-based products with improved quality and nutritional value. This review provides a comprehensive summary of the current knowledge on the structure and genetic regulation of starch formation in sorghum endosperm and highlights the potential for future research to further improve our understanding of this important process.
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Affiliation(s)
- Xuemin Kang
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China; School of Food Science and Engineering, Qilu University of Technology, Shandong Academy of Sciences, Jinan, Shandong 250353, China; Department of Food Science and Engineering, Shandong Agricultural University, Taian 271018, China
| | - Wei Gao
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China; School of Food Science and Engineering, Qilu University of Technology, Shandong Academy of Sciences, Jinan, Shandong 250353, China
| | - Bo Cui
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China; School of Food Science and Engineering, Qilu University of Technology, Shandong Academy of Sciences, Jinan, Shandong 250353, China; Department of Food Science and Engineering, Shandong Agricultural University, Taian 271018, China.
| | - A M Abd El-Aty
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China; Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, 12211 Giza, Egypt; Department of Medical Pharmacology, Medical Faculty, Ataturk University, 25240 Erzurum, Turkey
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5
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Ning L, Wang Y, Shi X, Zhou L, Ge M, Liang S, Wu Y, Zhang T, Zhao H. Nitrogen-dependent binding of the transcription factor PBF1 contributes to the balance of protein and carbohydrate storage in maize endosperm. THE PLANT CELL 2023; 35:409-434. [PMID: 36222567 PMCID: PMC9806651 DOI: 10.1093/plcell/koac302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Fluctuations in nitrogen (N) availability influence protein and starch levels in maize (Zea mays) seeds, yet the underlying mechanism is not well understood. Here, we report that N limitation impacted the expression of many key genes in N and carbon (C) metabolism in the developing endosperm of maize. Notably, the promoter regions of those genes were enriched for P-box sequences, the binding motif of the transcription factor prolamin-box binding factor 1 (PBF1). Loss of PBF1 altered accumulation of starch and proteins in endosperm. Under different N conditions, PBF1 protein levels remained stable but PBF1 bound different sets of target genes, especially genes related to the biosynthesis and accumulation of N and C storage products. Upon N-starvation, the absence of PBF1 from the promoters of some zein genes coincided with their reduced expression, suggesting that PBF1 promotes zein accumulation in the endosperm. In addition, PBF1 repressed the expression of sugary1 (Su1) and starch branching enzyme 2b (Sbe2b) under normal N supply, suggesting that, under N-deficiency, PBF1 redirects the flow of C skeletons for zein toward the formation of C compounds. Overall, our study demonstrates that PBF1 modulates C and N metabolism during endosperm development in an N-dependent manner.
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Affiliation(s)
| | | | - Xi Shi
- Institute of Crop Germplasm and Biotechnology, Jiangsu Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, 210014, China
| | - Ling Zhou
- Institute of Crop Germplasm and Biotechnology, Jiangsu Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, 210014, China
| | - Min Ge
- Institute of Crop Germplasm and Biotechnology, Jiangsu Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, 210014, China
| | - Shuaiqiang Liang
- Institute of Crop Germplasm and Biotechnology, Jiangsu Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, 210014, China
| | - Yibo Wu
- Institute of Crop Germplasm and Biotechnology, Jiangsu Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, 210014, China
| | - Tifu Zhang
- Institute of Crop Germplasm and Biotechnology, Jiangsu Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, 210014, China
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6
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Hershberger J, Tanaka R, Wood JC, Kaczmar N, Wu D, Hamilton JP, DellaPenna D, Buell CR, Gore MA. Transcriptome-wide association and prediction for carotenoids and tocochromanols in fresh sweet corn kernels. THE PLANT GENOME 2022; 15:e20197. [PMID: 35262278 DOI: 10.1002/tpg2.20197] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 01/23/2022] [Indexed: 06/14/2023]
Abstract
Sweet corn (Zea mays L.) is consistently one of the most highly consumed vegetables in the United States, providing a valuable opportunity to increase nutrient intake through biofortification. Significant variation for carotenoid (provitamin A, lutein, zeaxanthin) and tocochromanol (vitamin E, antioxidants) levels is present in temperate sweet corn germplasm, yet previous genome-wide association studies (GWAS) of these traits have been limited by low statistical power and mapping resolution. Here, we employed a high-quality transcriptomic dataset collected from fresh sweet corn kernels to conduct transcriptome-wide association studies (TWAS) and transcriptome prediction studies for 39 carotenoid and tocochromanol traits. In agreement with previous GWAS findings, TWAS detected significant associations for four causal genes, β-carotene hydroxylase (crtRB1), lycopene epsilon cyclase (lcyE), γ-tocopherol methyltransferase (vte4), and homogentisate geranylgeranyltransferase (hggt1) on a transcriptome-wide level. Pathway-level analysis revealed additional associations for deoxy-xylulose synthase2 (dxs2), diphosphocytidyl methyl erythritol synthase2 (dmes2), cytidine methyl kinase1 (cmk1), and geranylgeranyl hydrogenase1 (ggh1), of which, dmes2, cmk1, and ggh1 have not previously been identified through maize association studies. Evaluation of prediction models incorporating genome-wide markers and transcriptome-wide abundances revealed a trait-dependent benefit to the inclusion of both genomic and transcriptomic data over solely genomic data, but both transcriptome- and genome-wide datasets outperformed a priori candidate gene-targeted prediction models for most traits. Altogether, this study represents an important step toward understanding the role of regulatory variation in the accumulation of vitamins in fresh sweet corn kernels.
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Affiliation(s)
- Jenna Hershberger
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell Univ., Ithaca, NY, 14853, USA
| | - Ryokei Tanaka
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell Univ., Ithaca, NY, 14853, USA
| | - Joshua C Wood
- Dep. of Crop & Soil Sciences, Univ. of Georgia, Athens, GA, 30602, USA
| | - Nicholas Kaczmar
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell Univ., Ithaca, NY, 14853, USA
| | - Di Wu
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell Univ., Ithaca, NY, 14853, USA
| | - John P Hamilton
- Dep. of Crop & Soil Sciences, Univ. of Georgia, Athens, GA, 30602, USA
| | - Dean DellaPenna
- Dep. of Biochemistry and Molecular Biology, Michigan State Univ., East Lansing, MI, 48824, USA
| | - C Robin Buell
- Dep. of Crop & Soil Sciences, Univ. of Georgia, Athens, GA, 30602, USA
| | - Michael A Gore
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell Univ., Ithaca, NY, 14853, USA
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7
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He S, Hao X, Wang S, Zhou W, Ma Q, Lu X, Chen L, Zhang P. Starch synthase II plays a crucial role in starch biosynthesis and the formation of multienzyme complexes in cassava storage roots. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:2540-2557. [PMID: 35134892 DOI: 10.1093/jxb/erac022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 02/02/2022] [Indexed: 06/14/2023]
Abstract
Starch is a glucose polymer synthesized by green plants for energy storage and is crucial for plant growth and reproduction. The biosynthesis of starch polysaccharides is mediated by members of the large starch synthase (SS) protein superfamily. Here, we showed that in cassava storage roots, soluble starch synthase II (MeSSII) plays an important role in starch biosynthesis and the formation of protein complexes with other starch biosynthetic enzymes by directly interacting with MeSSI, MeSBEII, and MeISAII. MeSSII-RNAi cassava lines showed increased amylose content and reduced biosynthesis of the intermediate chain of amylopectin (B1 type) in their storage roots, leading to altered starch physicochemical properties. Furthermore, gel permeation chromatography analysis of starch biosynthetic enzymes between wild type and MeSSII-RNAi lines confirmed the key role of MeSSII in the organization of heteromeric starch synthetic protein complexes. The lack of MeSSII in cassava also reduced the capacity of MeSSI, MeSBEII, MeISAI, and MeISAII to bind to starch granules. These findings shed light on the key components of the starch biosynthesis machinery in root crops.
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Affiliation(s)
- Shutao He
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xiaomeng Hao
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Shanshan Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Wenzhi Zhou
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Qiuxiang Ma
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xinlu Lu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Luonan Chen
- Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Key Laboratory of Systems Health Science of Zhejiang Province, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China
- Guangdong Institute of Intelligence Science and Technology, Hengqin, Zhuhai, Guangdong, China
| | - Peng Zhang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
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8
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Yu B, Xiang D, Mahfuz H, Patterson N, Bing D. Understanding Starch Metabolism in Pea Seeds towards Tailoring Functionality for Value-Added Utilization. Int J Mol Sci 2021; 22:8972. [PMID: 34445676 PMCID: PMC8396644 DOI: 10.3390/ijms22168972] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 08/16/2021] [Accepted: 08/16/2021] [Indexed: 11/17/2022] Open
Abstract
Starch is the most abundant storage carbohydrate and a major component in pea seeds, accounting for about 50% of dry seed weight. As a by-product of pea protein processing, current uses for pea starch are limited to low-value, commodity markets. The globally growing demand for pea protein poses a great challenge for the pea fractionation industry to develop new markets for starch valorization. However, there exist gaps in our understanding of the genetic mechanism underlying starch metabolism, and its relationship with physicochemical and functional properties, which is a prerequisite for targeted tailoring functionality and innovative applications of starch. This review outlines the understanding of starch metabolism with a particular focus on peas and highlights the knowledge of pea starch granule structure and its relationship with functional properties, and industrial applications. Using the currently available pea genetics and genomics knowledge and breakthroughs in omics technologies, we discuss the perspectives and possible avenues to advance our understanding of starch metabolism in peas at an unprecedented level, to ultimately enable the molecular design of multi-functional native pea starch and to create value-added utilization.
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Affiliation(s)
- Bianyun Yu
- Aquatic and Crop Resource Development Research Centre, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9, Canada; (D.X.); (H.M.); (N.P.)
| | - Daoquan Xiang
- Aquatic and Crop Resource Development Research Centre, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9, Canada; (D.X.); (H.M.); (N.P.)
| | - Humaira Mahfuz
- Aquatic and Crop Resource Development Research Centre, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9, Canada; (D.X.); (H.M.); (N.P.)
- Department of Biology, Faculty of Science, University of Ottawa, 30 Marie Curie, Ottawa, ON K1N 6N5, Canada
| | - Nii Patterson
- Aquatic and Crop Resource Development Research Centre, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9, Canada; (D.X.); (H.M.); (N.P.)
| | - Dengjin Bing
- Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, 6000 C and E Trail, Lacombe, AB T4L 1W1, Canada;
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9
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Su B, Zhang X, Li L, Abbas S, Yu M, Cui Y, Baluška F, Hwang I, Shan X, Lin J. Dynamic spatial reorganization of BSK1 complexes in the plasma membrane underpins signal-specific activation for growth and immunity. MOLECULAR PLANT 2021; 14:588-603. [PMID: 33524551 DOI: 10.1016/j.molp.2021.01.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 01/26/2021] [Accepted: 01/26/2021] [Indexed: 05/25/2023]
Abstract
Growth and immunity are opposing processes that compete for cellular resources, and proper resource allocation is crucial for plant survival. BSK1 plays a key role in the regulation of both growth and immunity by associating with BRI1 and FLS2, respectively. However, it remains unclear how two antagonistic signals co-opt BSK1 to induce signal-specific activation. Here we show that the dynamic spatial reorganization of BSK1 within the plasma membrane underlies the mechanism of signal-specific activation for growth or immunity. Resting BSK1 localizes to membrane rafts as complexes. Unlike BSK1-associated FLS2 and BRI1, flg22 or exogenous brassinosteroid (BR) treatment did not decrease BSK1 levels at the plasma membrane (PM) but rather induced BSK1 multimerization and dissociation from FLS2/BSK1 or BRI1/BSK1, respectively. Moreover, flg22-activated BSK1 translocated from membrane rafts to non-membrane-raft regions, whereas BR-activated BSK1 remained in membrane rafts. When applied together with flg22, BR suppressed various flg22-induced BSK1 activities such as BSK1 dissociation from FLS2/BSK1, BSK1 interaction with MAPKKK5, and BSK translocation together with MAPKKK5. Taken together, this study provides a unique insight into how the precise control of BSK1 spatiotemporal organization regulates the signaling specificity to balance plant growth and immunity.
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Affiliation(s)
- Bodan Su
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China; College of Biological Sciences & Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Xi Zhang
- College of Biological Sciences & Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Li Li
- College of Biological Sciences & Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Sammar Abbas
- College of Biological Sciences & Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Meng Yu
- College of Biological Sciences & Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Yaning Cui
- College of Biological Sciences & Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - František Baluška
- Institute of Cellular and Molecular Botany, University of Bonn, Bonn, 53115, Germany
| | - Inhwan Hwang
- College of Biological Sciences & Biotechnology, Beijing Forestry University, Beijing 100083, China; Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Xiaoyi Shan
- College of Biological Sciences & Biotechnology, Beijing Forestry University, Beijing 100083, China.
| | - Jinxing Lin
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China; College of Biological Sciences & Biotechnology, Beijing Forestry University, Beijing 100083, China.
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10
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Zou W, Liu K, Gao X, Yu C, Wang X, Shi J, Chao Y, Yu Q, Zhou G, Ge L. Diurnal variation of transitory starch metabolism is regulated by plastid proteins WXR1/WXR3 in Arabidopsis young seedlings. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:3074-3090. [PMID: 33571997 DOI: 10.1093/jxb/erab056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 02/05/2021] [Indexed: 06/12/2023]
Abstract
Transitory starch is the portion of starch that is synthesized during the day in the chloroplast and usually used for plant growth overnight. Here, we report altered metabolism of transitory starch in the wxr1/wxr3 (weak auxin response 1/3) mutants of Arabidopsis. WXR1/WXR3 were previously reported to regulate root growth of young seedlings and affect the auxin response mediated by auxin polar transport in Arabidopsis. In this study the wxr1/wxr3 mutants accumulated transitory starch in cotyledon, young leaf, and hypocotyl at the end of night. WXR1/WXR3 expression showed diurnal variation. Grafting experiments indicated that the WXRs in root were necessary for proper starch metabolism and plant growth. We also found that photosynthesis was inhibited and the transcription level of DIN1/DIN6 (Dark-Inducible 1/6) was reduced in wxr1/wxr3. The mutants also showed a defect in the ionic equilibrium of Na+ and K+, consistent with our bioinformatics data that genes related to ionic equilibrium were misregulated in wxr1. Loss of function of WXR1 also resulted in abnormal trafficking of membrane lipids and proteins. This study reveals that the plastid proteins WXR1/WXR3 play important roles in promoting transitory starch degradation for plant growth over night, possibly through regulating ionic equilibrium in the root.
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Affiliation(s)
- Wenjiao Zou
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Kui Liu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China
| | - Xueping Gao
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Changjiang Yu
- Center for Crop Panomics, College of Agronomy, Qingdao Agricultural University, Qingdao 266109, China
| | - Xiaofei Wang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Junjie Shi
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Yanru Chao
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Qian Yu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
- Center for Crop Panomics, College of Agronomy, Qingdao Agricultural University, Qingdao 266109, China
| | - Gongke Zhou
- Center for Crop Panomics, College of Agronomy, Qingdao Agricultural University, Qingdao 266109, China
| | - Lei Ge
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
- Center for Crop Panomics, College of Agronomy, Qingdao Agricultural University, Qingdao 266109, China
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11
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Blennow A, Skryhan K, Tanackovic V, Krunic SL, Shaik SS, Andersen MS, Kirk H, Nielsen KL. Non-GMO potato lines, synthesizing increased amylose and resistant starch, are mainly deficient in isoamylase debranching enzyme. PLANT BIOTECHNOLOGY JOURNAL 2020; 18:2096-2108. [PMID: 32096588 PMCID: PMC7540516 DOI: 10.1111/pbi.13367] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/31/2020] [Accepted: 02/17/2020] [Indexed: 05/04/2023]
Abstract
Solanum tuberosum potato lines with high amylose content were generated by crossing with the wild potato species Solanum sandemanii followed by repeated backcrossing to Solanum tuberosum lines. The trait, termed increased amylose (IAm), was recessive and present after three generations of backcrossing into S. tuberosum lines (6.25% S. sandemanii genes). The tubers of these lines were small, elongated and irregular with small and misshaped starch granules and high sugar content. Additional backcrossing resulted in less irregular tuber morphology, increased starch content (4.3%-9.5%) and increased amylose content (29%-37.9%) but indifferent sugar content. The amylose in the IAm starch granules was mainly located in peripheral spots, and large cavities were found in the granules. Starch pasting was suppressed, and the digestion-resistant starch (RS) content was increased. Comprehensive microarray polymer profiling (CoMPP) analysis revealed specific alterations of major pectic and glycoprotein cell wall components. This complex phenotype led us to search for candidate IAm genes exploiting its recessive trait. Hence, we sequenced genomic DNA of a pool of IAm lines, identified SNPs genome wide against the draft genome sequence of potato and searched for regions of decreased heterozygosity. Three regions, located on chromosomes 3, 7 and 10, respectively, displayed markedly less heterozygosity than average. The only credible starch metabolism-related gene found in these regions encoded the isoamylase-type debranching enzyme Stisa1. Decreased expression of mRNA (>500 fold) and reduced enzyme activity (virtually absent from IAm lines) supported Stisa1 as a candidate gene for IAm.
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Affiliation(s)
- Andreas Blennow
- Department of Plant and Environmental SciencesUniversity of CopenhagenFrederiksberg CDenmark
| | - Katsiaryna Skryhan
- Department of Plant and Environmental SciencesUniversity of CopenhagenFrederiksberg CDenmark
| | - Vanja Tanackovic
- Department of Plant and Environmental SciencesUniversity of CopenhagenFrederiksberg CDenmark
| | - Susanne L. Krunic
- Department of Plant and Environmental SciencesUniversity of CopenhagenFrederiksberg CDenmark
| | - Shahnoor S. Shaik
- Department of Plant and Environmental SciencesUniversity of CopenhagenFrederiksberg CDenmark
| | | | | | - Kåre L. Nielsen
- Department of Chemistry and BiologyAalborg UniversityAalborgDenmark
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12
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Starch and Glycogen Analyses: Methods and Techniques. Biomolecules 2020; 10:biom10071020. [PMID: 32660096 PMCID: PMC7407607 DOI: 10.3390/biom10071020] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 01/16/2023] Open
Abstract
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.
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13
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Pfister B, Zeeman SC, Rugen MD, Field RA, Ebenhöh O, Raguin A. Theoretical and experimental approaches to understand the biosynthesis of starch granules in a physiological context. PHOTOSYNTHESIS RESEARCH 2020; 145:55-70. [PMID: 31955343 PMCID: PMC7308250 DOI: 10.1007/s11120-019-00704-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 12/19/2019] [Indexed: 06/10/2023]
Abstract
Starch, a plant-derived insoluble carbohydrate composed of glucose polymers, is the principal carbohydrate in our diet and a valuable raw material for industry. The properties of starch depend on the arrangement of glucose units within the constituent polymers. However, key aspects of starch structure and the underlying biosynthetic processes are not well understood, limiting progress towards targeted improvement of our starch crops. In particular, the major component of starch, amylopectin, has a complex three-dimensional, branched architecture. This architecture stems from the combined actions of a multitude of enzymes, each having broad specificities that are difficult to capture experimentally. In this review, we reflect on experimental approaches and limitations to decipher the enzymes' specificities and explore possibilities for in silico simulations of these activities. We believe that the synergy between experimentation and simulation is needed for the correct interpretation of experimental data and holds the potential to greatly advance our understanding of the overall starch biosynthetic process. We furthermore propose that the formation of glucan secondary structures, concomitant with its synthesis, is a previously overlooked factor that directly affects amylopectin architecture through its impact on enzyme function.
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Affiliation(s)
- Barbara Pfister
- Department of Biology, Institute of Molecular Plant Biology, ETH Zurich, 8092, Zurich, Switzerland
| | - Samuel C Zeeman
- Department of Biology, Institute of Molecular Plant Biology, ETH Zurich, 8092, Zurich, Switzerland
| | - Michael D Rugen
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Robert A Field
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Oliver Ebenhöh
- Department of Biology, Institute of Quantitative and Theoretical Biology, Heinrich-Heine University, 40225, Düsseldorf, Germany
- Department of Biology, Cluster of Excellence on Plant Sciences, Institute of Quantitative and Theoretical Biology, Heinrich-Heine University, 40225, Düsseldorf, Germany
| | - Adélaïde Raguin
- Department of Biology, Institute of Quantitative and Theoretical Biology, Heinrich-Heine University, 40225, Düsseldorf, Germany.
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14
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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: 79] [Impact Index Per Article: 19.8] [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.
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Affiliation(s)
| | - Samuel C Zeeman
- Institute of Plant Molecular Biology, ETH Zürich, 8092 Zürich, Switzerland
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15
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Hu S, Sprintall J, Guan C, McPhaden MJ, Wang F, Hu D, Cai W. Deep-reaching acceleration of global mean ocean circulation over the past two decades. SCIENCE ADVANCES 2020; 105:108-123. [PMID: 32076640 DOI: 10.1111/tpj.15043] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 09/21/2020] [Indexed: 05/06/2023]
Abstract
Ocean circulation redistributes Earth's energy and water masses and influences global climate. Under historical greenhouse warming, regional ocean currents show diverse tendencies, but whether there is an emerging trend of the global mean ocean circulation system is not yet clear. Here, we show a statistically significant increasing trend in the globally integrated oceanic kinetic energy since the early 1990s, indicating a substantial acceleration of global mean ocean circulation. The increasing trend in kinetic energy is particularly prominent in the global tropical oceans, reaching depths of thousands of meters. The deep-reaching acceleration of the ocean circulation is mainly induced by a planetary intensification of surface winds since the early 1990s. Although possibly influenced by wind changes associated with the onset of a negative Pacific decadal oscillation since the late 1990s, the recent acceleration is far larger than that associated with natural variability, suggesting that it is principally part of a long-term trend.
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Affiliation(s)
- Shijian Hu
- CAS Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
- Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Janet Sprintall
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA
| | - Cong Guan
- CAS Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
- Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | | | - Fan Wang
- CAS Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
- Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dunxin Hu
- CAS Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
- Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenju Cai
- Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
- CSIRO Oceans and Atmosphere Flagship, Aspendale, Victoria 3195, Australia
- Centre for Southern Hemisphere Oceans Research (CSHOR), CSIRO Oceans and Atmosphere, Hobart, Tasmania 7004, Australia
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16
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Takahashi S, Kumagai Y, Igarashi H, Horimai K, Ito H, Shimada T, Kato Y, Hamada S. Biochemical analysis of a new sugary-type rice mutant, Hemisugary1, carrying a novel allele of the sugary-1 gene. PLANTA 2019; 251:29. [PMID: 31802247 DOI: 10.1007/s00425-019-03321-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 11/29/2019] [Indexed: 06/10/2023]
Abstract
A novel allele of the sugary-1 rice mutant was isolated. The single amino acid change led to isoamylase activity reduction and accumulation of high-molecular-weight phytoglycogen in seeds. A new sugary rice variety with an improved seed appearance has been isolated and designated Hemisugary1. This mutant, which was derived from Japonica-type cultivar Tsugaruroman treated with sodium azide, has about half the isoamylase activity of seeds in the original Tsugaruroman. The mutant also accumulates significant phytoglycogen, albeit approximately 40% of the total phytoglycogen in the existing sugary cultivar Ayunohikari which is defective in its most isoamylase activity. The site of mutation was identified using a re-sequence of the whole genome and a cleaved amplified polymorphic sequence (CAPS) marker. The hemisugary phenotypes of the F2 progeny were entirely consistent with the results of genotyping using the CAPS marker. Segregation analysis of the F2 population showed that the hemisugary phenotype was controlled by a single recessive gene, which was produced by a G → A single nucleotide polymorphism in the sugary-1 gene, resulting in a missense mutation from glycine to aspartic acid at amino acid position 333. Zymogram showed that this amino acid replacement resulted in a decrease in isoamylase activity with a concomitant reduction in the formation of isoamylase complexes. Phytoglycogen molecules from Hemisugary1 seeds were 3.5 times larger and contained more short glucan chains than did Ayunohikari seeds. Our data provide new insights into the relationship between isoamylase structure and phytoglycogen formation.
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Affiliation(s)
- Sumire Takahashi
- Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori, 036-8561, Japan
| | - Yu Kumagai
- Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori, 036-8561, Japan
| | - Hidenari Igarashi
- Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori, 036-8561, Japan
| | - Karin Horimai
- Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori, 036-8561, Japan
| | - Hiroyuki Ito
- Department of Chemical and Biological Engineering, National Institute of Technology, Akita College, 1-1 Iijima-Bunkyo-cho, Akita, 011-8511, Japan
| | - Toru Shimada
- Faculty of Education, Hirosaki University, 1 Bunkyo-cho, Hirosaki, Aomori, 036-8560, Japan
| | - Yoji Kato
- Faculty of Education, Hirosaki University, 1 Bunkyo-cho, Hirosaki, Aomori, 036-8560, Japan
| | - Shigeki Hamada
- Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori, 036-8561, Japan.
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17
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Abstract
sugary enhancer1 (se1) is a naturally occurring mutant allele involved in starch metabolism in maize endosperm. It is a recessive modifier of sugary1 (su1) and commercially important in modern sweet corn breeding, but its molecular identity and mode of action remain unknown. Here, we developed a pair of near-isogenic lines, W822Gse (su1-ref/su1-ref se1/se1) and W822GSe (su1-ref/su1-ref Se1/Se1), that Mendelize the se1 phenotype in an su1-ref background. W822Gse kernels have lower starch and higher water soluble polysaccharide and sugars than W822GSe kernels. Using high-resolution genetic mapping, we found that wild-type Se1 is a gene Zm00001d007657 on chromosome 2 and a deletion of this gene causes the se1 phenotype. Comparative metabolic profiling of seed tissue between these 2 isolines revealed the remarkable difference in carbohydrate metabolism, with sucrose and maltose highly accumulated in the mutant. Se1 is predominantly expressed in the endosperm, with low expression in leaf and root tissues. Differential expression analysis identified genes enriched in both starch biosynthesis and degradation processes, indicating a pleiotropic regulatory effect of se1 Repressed expression of Se1 and Su1 in RNA interference-mediated transgenic maize validates that deletion of the gene identified as Se1 is a true causal gene responsible for the se1 phenotype. The findings contribute to our understanding of starch metabolism in cereal crops.
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18
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Dong Q, Xu Q, Kong J, Peng X, Zhou W, Chen L, Wu J, Xiang Y, Jiang H, Cheng B. Overexpression of ZmbZIP22 gene alters endosperm starch content and composition in maize and rice. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 283:407-415. [PMID: 31128711 DOI: 10.1016/j.plantsci.2019.03.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 02/28/2019] [Accepted: 03/01/2019] [Indexed: 05/23/2023]
Abstract
Starch content and composition are major determinants of yield and quality in maize. In recent years, the major genes for starch metabolism have been cloned in this species. However, the role of transcription factors in regulating the starch metabolism pathway remains unclear. The ZmbZIP22 gene encodes a bZIP transcription factor. In our study, plants overexpressing ZmbZIP22 showed reductions in the size of starch granules, the size and weight of seeds, reduced amylose content, and alterations in the chemical structure of starch granules. Also, overexpression of ZmbZIP22 resulted in increases in the contents of soluble sugars and reducing sugars in transgenic rice and maize. ZmbZIP22 promotes the transcription of starch metabolism genes by binding to their promoters. Screening by yeast one-hybrid assays indicated a possible interaction between ZmbZIP22 and the promoters of eight key starch enzyme genes. Collectively, our results indicated that ZmbZIP22 functions as a negative regulator of starch synthesis, and suggest that this occurs through the regulation of key sugar and starch metabolism genes in maize.
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Affiliation(s)
- Qing Dong
- National Engineering Laboratory of Crop Stress Resistence, Anhui Agricultural University, Hefei, 230036, China; Maize Research Center, Anhui Academy of Agricultural Sciences, Hefei, 230031, China
| | - Qianqian Xu
- National Engineering Laboratory of Crop Stress Resistence, Anhui Agricultural University, Hefei, 230036, China
| | - Jingjing Kong
- National Engineering Laboratory of Crop Stress Resistence, Anhui Agricultural University, Hefei, 230036, China
| | - Xiaojian Peng
- National Engineering Laboratory of Crop Stress Resistence, Anhui Agricultural University, Hefei, 230036, China
| | - Wei Zhou
- National Engineering Laboratory of Crop Stress Resistence, Anhui Agricultural University, Hefei, 230036, China
| | - Long Chen
- National Engineering Laboratory of Crop Stress Resistence, Anhui Agricultural University, Hefei, 230036, China
| | - Jiandong Wu
- National Engineering Laboratory of Crop Stress Resistence, Anhui Agricultural University, Hefei, 230036, China
| | - Yan Xiang
- National Engineering Laboratory of Crop Stress Resistence, Anhui Agricultural University, Hefei, 230036, China
| | - Haiyang Jiang
- National Engineering Laboratory of Crop Stress Resistence, Anhui Agricultural University, Hefei, 230036, China.
| | - Beijiu Cheng
- National Engineering Laboratory of Crop Stress Resistence, Anhui Agricultural University, Hefei, 230036, China.
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19
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Seung D, Smith AM. Starch granule initiation and morphogenesis-progress in Arabidopsis and cereals. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:771-784. [PMID: 30452691 DOI: 10.1093/jxb/ery412] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 11/06/2018] [Indexed: 05/13/2023]
Abstract
Starch, the major storage carbohydrate in plants, is synthesized in plastids as semi-crystalline, insoluble granules. Many organs and cell types accumulate starch at some point during their development and maturation. The biosynthesis of the starch polymers, amylopectin and amylose, is relatively well understood and mostly conserved between organs and species. However, we are only beginning to understand the mechanism by which starch granules are initiated, and the factors that control the number of granules per plastid and the size/shape of granules. Here, we review recent progress in understanding starch granule initiation and morphogenesis. In Arabidopsis, granule initiation requires several newly discovered proteins with specific locations within the chloroplast, and also on the availability of maltooligosaccharides which act as primers for initiation. We also describe progress in understanding granule biogenesis in the endosperm of cereal grains-within which there is large interspecies variation in granule initiation patterns and morphology. Investigating whether this diversity results from differences between species in the functions of known proteins, and/or from the presence of novel, unidentified proteins, is a promising area of future research. Expanding our knowledge in these areas will lead to new strategies for improving the quality of cereal crops by modifying starch granule size and shape in vivo.
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Affiliation(s)
- David Seung
- John Innes Centre, Norwich Research Park, Norwich, UK
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20
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Ramadoss BR, Gangola MP, Agasimani S, Jaiswal S, Venkatesan T, Sundaram GR, Chibbar RN. Starch granule size and amylopectin chain length influence starch in vitro enzymatic digestibility in selected rice mutants with similar amylose concentration. Journal of Food Science and Technology 2018; 56:391-400. [PMID: 30728582 DOI: 10.1007/s13197-018-3500-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 11/01/2018] [Accepted: 11/07/2018] [Indexed: 10/27/2022]
Abstract
In human diet, the products of starch digestion are a major energy source. Starch is stored as water insoluble granules composed of amylose and amylopectin. The susceptibility of starch granule to digestive enzymes is affected by starch granule size, shape, and composition. In this study, starch characteristics and in vitro enzymatic hydrolysis in three rice (Oryza sativa L.) mutants (RSML 184, RSML 278 and RSML 352) with similar amylose concentration (24.3-25.8%) was compared to parent ADT 43 (21.4%). The three mutants had reduced thousand grain weight and starch concentration but higher protein and dietary fiber concentrations. The mutant RSML 352 had small starch granules and reduced short glucan chains [Degree of polymerization (DP) 6-12] compared to the other two mutants (RSML 184 and RSML 278). The mutant RSML 352 had the highest hydrolytic index (HI) and least concentration of resistant starch (RS) compared to the other two mutants and parent rice ADT 43. The two rice mutants (RSML 184 and RSML 278) had reduced HI and increased RS concentration than the parent ADT 43. The results showed that starch granule size and amylopectin structure influence starch enzymatic digestibility and RS concentration.
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Affiliation(s)
- Bharathi Raja Ramadoss
- 1Department of Plant Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8 Canada
| | - Manu Pratap Gangola
- 1Department of Plant Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8 Canada
| | - Somanath Agasimani
- 2University of Agricultural Sciences, Bangalore, Karnataka 560 065 India
| | - Sarita Jaiswal
- 1Department of Plant Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8 Canada
| | - Thiruvengadam Venkatesan
- 3Department of Plant Genetic Resources, Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu 641 003 India
| | - Ganesh Ram Sundaram
- 3Department of Plant Genetic Resources, Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu 641 003 India
| | - Ravindra N Chibbar
- 1Department of Plant Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8 Canada
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21
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Goren A, Ashlock D, Tetlow IJ. Starch formation inside plastids of higher plants. PROTOPLASMA 2018; 255:1855-1876. [PMID: 29774409 DOI: 10.1007/s00709-018-1259-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/03/2018] [Indexed: 05/09/2023]
Abstract
Starch is a water-insoluble polyglucan synthesized inside the plastid stroma within plant cells, serving a crucial role in the carbon budget of the whole plant by acting as a short-term and long-term store of energy. The highly complex, hierarchical structure of the starch granule arises from the actions of a large suite of enzyme activities, in addition to physicochemical self-assembly mechanisms. This review outlines current knowledge of the starch biosynthetic pathway operating in plant cells in relation to the micro- and macro-structures of the starch granule. We highlight the gaps in our knowledge, in particular, the relationship between enzyme function and operation at the molecular level and the formation of the final, macroscopic architecture of the granule.
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Affiliation(s)
- Asena Goren
- Department of Mathematics and Statistics, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Daniel Ashlock
- Department of Mathematics and Statistics, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Ian J Tetlow
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, Guelph, ON, N1G 2W1, Canada.
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22
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Panpetch P, Field RA, Limpaseni T. Heterologous co-expression in E. coli of isoamylase genes from cassava Manihot esculenta Crantz 'KU50' achieves enzyme-active heteromeric complex formation. PLANT MOLECULAR BIOLOGY 2018; 96:417-427. [PMID: 29380100 DOI: 10.1007/s11103-018-0707-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 01/20/2018] [Indexed: 06/07/2023]
Abstract
Cloning of two isoamylase genes, MeISA1 and MeISA2, from cassava (Manihot esculenta Crantz) tubers, accompanied by their co-expression in E. coli demonstrates a requirement for heteromeric complex formation to achieve debranching activity. Starch debranching enzyme (DBE) or isoamylase (ISA) (EC.3.2.1.68), an important enzyme in starch metabolism, catalyses the hydrolysis of α-1,6 glycosidic linkages of amylopectin. Isoforms of ISAs have been reported in higher plants and algae (Fujita et al. in Planta 208:283-293, 1999; Hussain et al. in Plant Cell 15:133-149, 2003; Ishizaki et al. in Agric Biol Chem 47:771-779, 1983; Mouille et al. in Plant Cell 8:1353-1366, 1996). In the current work, cassava ISA genes were isolated from cDNA generated from total RNA from tubers of Manihot esculanta Crantz cultivar KU50. MeISA1 and MeISA2 were successfully amplified and cloned into a pETDuet1 vector. The putative MeISA1 and MeISA2 proteins comprised 763 and 882 amino acids, with substantial similarity to StISA1 and StISA2 from potato (84.4% and 68.9%, respectively). Recombinant MeISA1 and MeISA2 were co-expressed in Escherichia coli SoluBL21 (DE3). HistrapTM-Purified rMeISA1 and rMeISA2 showed approximate molecular weights of 87 and 99 kDa, respectively, by SDS-PAGE. Debranching activity was only detectable in the column fractions where both recombinant ISA isoforms were present. The heteromeric DBE from crude extracts of 4-5 h induced cultures analysed by gel filtration chromatography and western blot showed combinations of rMeISA1 and rMeISA2 at ratios of 1:1 to 4:1. Pooled fractions with DBE activity were used for enzyme characterisation, which showed that the enzyme was specific for amylopectin, with optimum activity at 37 °C and pH 7.0. Enzyme activity was enhanced by Co2+, Mg2+ and Ca2+, but was strongly inhibited by Cu2+. Debranched amylopectin products showed chain length distributions typical of plant DBE.
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Affiliation(s)
- Pawinee Panpetch
- Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Robert A Field
- Department of Biological Chemistry, John Innes Centre, Norwich, NR4 7UH, UK
| | - Tipaporn Limpaseni
- Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
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Functions of maize genes encoding pyruvate phosphate dikinase in developing endosperm. Proc Natl Acad Sci U S A 2017; 115:E24-E33. [PMID: 29255019 DOI: 10.1073/pnas.1715668115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Maize opaque2 (o2) mutations are beneficial for endosperm nutritional quality but cause negative pleiotropic effects for reasons that are not fully understood. Direct targets of the bZIP transcriptional regulator encoded by o2 include pdk1 and pdk2 that specify pyruvate phosphate dikinase (PPDK). This enzyme reversibly converts AMP, pyrophosphate, and phosphoenolpyruvate to ATP, orthophosphate, and pyruvate and provides diverse functions in plants. This study addressed PPDK function in maize starchy endosperm where it is highly abundant during grain fill. pdk1 and pdk2 were inactivated individually by transposon insertions, and both genes were simultaneously targeted by endosperm-specific RNAi. pdk2 accounts for the large majority of endosperm PPDK, whereas pdk1 specifies the abundant mesophyll form. The pdk1- mutation is seedling-lethal, indicating that C4 photosynthesis is essential in maize. RNAi expression in transgenic endosperm eliminated detectable PPDK protein and enzyme activity. Transgenic kernels weighed the same on average as nontransgenic siblings, with normal endosperm starch and total N contents, indicating that PPDK is not required for net storage compound synthesis. An opaque phenotype resulted from complete PPDK knockout, including loss of vitreous endosperm character similar to the phenotype conditioned by o2-. Concentrations of multiple glycolytic intermediates were elevated in transgenic endosperm, energy charge was altered, and starch granules were more numerous but smaller on average than normal. The data indicate that PPDK modulates endosperm metabolism, potentially through reversible adjustments to energy charge, and reveal that o2- mutations can affect the opaque phenotype through regulation of PPDK in addition to their previously demonstrated effects on storage protein gene expression.
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24
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Li Z, Ji K, Zhou J, Ye X, Wang T, Luo X, Huang Y, Cao H, Cui Z, Kong Y. A debranching enzyme IsoM of Corallococcus sp. strain EGB with potential in starch processing. Int J Biol Macromol 2017; 105:1300-1309. [DOI: 10.1016/j.ijbiomac.2017.07.153] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/25/2017] [Accepted: 07/26/2017] [Indexed: 01/30/2023]
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Abstract
The starch-rich endosperms of the Poaceae, which includes wild grasses and their domesticated descendents the cereals, have provided humankind and their livestock with the bulk of their daily calories since the dawn of civilization up to the present day. There are currently unprecedented pressures on global food supplies, largely resulting from population growth, loss of agricultural land that is linked to increased urbanization, and climate change. Since cereal yields essentially underpin world food and feed supply, it is critical that we understand the biological factors contributing to crop yields. In particular, it is important to understand the biochemical pathway that is involved in starch biosynthesis, since this pathway is the major yield determinant in the seeds of six out of the top seven crops grown worldwide. This review outlines the critical stages of growth and development of the endosperm tissue in the Poaceae, including discussion of carbon provision to the growing sink tissue. The main body of the review presents a current view of our understanding of storage starch biosynthesis, which occurs inside the amyloplasts of developing endosperms.
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Review: Amylopectin synthesis and hydrolysis – Understanding isoamylase and limit dextrinase and their impact on starch structure on barley ( Hordeum vulgare ) quality. Trends Food Sci Technol 2017. [DOI: 10.1016/j.tifs.2016.11.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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27
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Nabemoto M, Watanabe R, Ohsu M, Sato K, Otani M, Nakayachi O, Watanabe M. Molecular characterization of genes encoding isoamylase-type debranching enzyme in tuberous root of sweet potato, Ipomoea batatas (L.) Lam. PLANT BIOTECHNOLOGY (TOKYO, JAPAN) 2016; 33:351-359. [PMID: 31274996 PMCID: PMC6587035 DOI: 10.5511/plantbiotechnology.16.0926a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 09/26/2016] [Indexed: 06/09/2023]
Abstract
Isoamylase (ISA) is a starch debranching enzyme that removes α-1,6-glucosidic linkages in α-polyglucans such as amylopectin. From previous studies, plant isoamylases have been shown to play a crucial role in amylopectin biosynthesis; however, little is known about their function in storage root tissues of plants such as cassava, yam and sweet potato. In this study, we isolated cDNA clones and characterized the cDNA nucleotide sequences of three genes (IbISA1, IbISA2, IbISA3) encoding isoamylase from sweet potato (Ipomoea batatas (L.) cv. White Star). Deduced amino acid sequences of the three isolated IbISAs have the specific regions that are highly conserved among the α-amylase family members. The product of IbISA2 is predicted to be enzymatically inactive, like other plant ISA2s, due to replacement of amino acid residues that are important for hydrolytic reaction. qRT-PCR analysis demonstrated that expression of IbISA2 was higher than that of the other two IbISAs (IbISA1 and IbISA3) in tuberous root at 109 days after planting, at which stage of tuberous root was at which stage tuberous roots were almost fully developed almost developed. This expression pattern observed in our experiments was different from that in other sink organs, such as seeds (endosperms), indicating that orchestration of ISA gene expression may depend on the differences in sink organ type between tuberous roots and seeds. The molecular characterization of three IbISA genes and their expression analysis in this study will contribute to further studies on starch biosynthesis in sweet potato, especially in storage root.
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Affiliation(s)
- Moe Nabemoto
- Reseach Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa 921-8836, Japan
- Laboratory of Plant Reproductive Genetics, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Riho Watanabe
- Reseach Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa 921-8836, Japan
| | - Mizuho Ohsu
- Reseach Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa 921-8836, Japan
| | - Kaname Sato
- Reseach Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa 921-8836, Japan
| | - Motoyasu Otani
- Reseach Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa 921-8836, Japan
| | - Osamu Nakayachi
- Reseach Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa 921-8836, Japan
| | - Masao Watanabe
- Laboratory of Plant Reproductive Genetics, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
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Yu T, Li G, Dong S, Liu P, Zhang J, Zhao B. Proteomic analysis of maize grain development using iTRAQ reveals temporal programs of diverse metabolic processes. BMC PLANT BIOLOGY 2016; 16:241. [PMID: 27809771 PMCID: PMC5095984 DOI: 10.1186/s12870-016-0878-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 08/18/2016] [Indexed: 05/20/2023]
Abstract
BACKGROUND Grain development in maize is an essential process in the plant's life cycle and is vital for use of the plant as a crop for animals and humans. However, little is known regarding the protein regulatory networks that control grain development. Here, isobaric tag for relative and absolute quantification (iTRAQ) technology was used to analyze temporal changes in protein expression during maize grain development. RESULTS Maize grain proteins and changes in protein expression at eight developmental stages from 3 to 50 d after pollination (DAP) were performed using iTRAQ-based proteomics. Overall, 4751 proteins were identified; 2639 of these were quantified and 1235 showed at least 1.5-fold changes in expression levels at different developmental stages and were identified as differentially expressed proteins (DEPs). The DEPs were involved in different cellular and metabolic processes with a preferential distribution to protein synthesis/destination and metabolism categories. A K-means clustering analysis revealed coordinated protein expression associated with different functional categories/subcategories at different development stages. CONCLUSIONS Our results revealed developing maize grain display different proteomic characteristics at distinct stages, such as numerous DEPs for cell growth/division were highly expressed during early stages, whereas those for starch biosynthesis and defense/stress accumulated in middle and late stages, respectively. We also observed coordinated expression of multiple proteins of the antioxidant system, which are essential for the maintenance of reactive oxygen species (ROS) homeostasis during grain development. Particularly, some DEPs, such as zinc metallothionein class II, pyruvate orthophosphate dikinase (PPDK) and 14-3-3 proteins, undergo major changes in expression at specific developmental stages, suggesting their roles in maize grain development. These results provide a valuable resource for analyzing protein function on a global scale and also provide new insights into the potential protein regulatory networks that control grain yield and quality.
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Affiliation(s)
- Tao Yu
- State Key Laboratory of Crop Biology and College of Agronomy, Shandong Agricultural University, Taian, 271018 Shandong People’s Republic of China
| | - Geng Li
- State Key Laboratory of Crop Biology and College of Agronomy, Shandong Agricultural University, Taian, 271018 Shandong People’s Republic of China
| | - Shuting Dong
- State Key Laboratory of Crop Biology and College of Agronomy, Shandong Agricultural University, Taian, 271018 Shandong People’s Republic of China
| | - Peng Liu
- State Key Laboratory of Crop Biology and College of Agronomy, Shandong Agricultural University, Taian, 271018 Shandong People’s Republic of China
| | - Jiwang Zhang
- State Key Laboratory of Crop Biology and College of Agronomy, Shandong Agricultural University, Taian, 271018 Shandong People’s Republic of China
| | - Bin Zhao
- State Key Laboratory of Crop Biology and College of Agronomy, Shandong Agricultural University, Taian, 271018 Shandong People’s Republic of China
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29
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Sestili F, Sparla F, Botticella E, Janni M, D'Ovidio R, Falini G, Marri L, Cuesta-Seijo JA, Moscatello S, Battistelli A, Trost P, Lafiandra D. The down-regulation of the genes encoding Isoamylase 1 alters the starch composition of the durum wheat grain. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 252:230-238. [PMID: 27717459 DOI: 10.1016/j.plantsci.2016.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 08/02/2016] [Accepted: 08/04/2016] [Indexed: 05/20/2023]
Abstract
In rice, maize and barley, the lack of Isoamylase 1 activity materially affects the composition of endosperm starch. Here, the effect of this deficiency in durum wheat has been characterized, using transgenic lines in which Isa1 was knocked down via RNAi. Transcriptional profiling confirmed the partial down-regulation of Isa1 and revealed a pleiotropic effect on the level of transcription of genes encoding other isoamylases, pullulanase and sucrose synthase. The polysaccharide content of the transgenic endosperms was different from that of the wild type in a number of ways, including a reduction in the content of starch and a moderate enhancement of both phytoglycogen and β-glucan. Some alterations were also induced in the distribution of amylopectin chain length and amylopectin fine structure. The amylopectin present in the transgenic endosperms was more readily hydrolyzable after a treatment with hydrochloric acid, which disrupted its semi-crystalline structure. The conclusion was that in durum wheat, Isoamylase 1 is important for both the synthesis of amylopectin and for determining its internal structure.
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Affiliation(s)
- Francesco Sestili
- Department of Agricultural and Forestry Sciences DAFNE, University of Tuscia, Via S. Camillo de Lellis, SNC, 01100 Viterbo, Italy.
| | - Francesca Sparla
- Department of Pharmacy and Biotechnology FABIT, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy.
| | - Ermelinda Botticella
- Department of Agricultural and Forestry Sciences DAFNE, University of Tuscia, Via S. Camillo de Lellis, SNC, 01100 Viterbo, Italy.
| | - Michela Janni
- Department of Agricultural and Forestry Sciences DAFNE, University of Tuscia, Via S. Camillo de Lellis, SNC, 01100 Viterbo, Italy; National Research Council CNR-Istituto di Bioscienze e Biorisorse, Via G. Amendola, 165, 70126 Bari, Italy.
| | - Renato D'Ovidio
- Department of Agricultural and Forestry Sciences DAFNE, University of Tuscia, Via S. Camillo de Lellis, SNC, 01100 Viterbo, Italy.
| | - Giuseppe Falini
- Department of Chemistry "G. Ciamician", University of Bologna, Via Selmi 2, 40126 Bologna, Italy.
| | - Lucia Marri
- Carlsberg Research Laboratory, Gamle Carlsberg Vej 10, Copenhagen, V DK-1799, Denmark.
| | - Jose A Cuesta-Seijo
- Carlsberg Research Laboratory, Gamle Carlsberg Vej 10, Copenhagen, V DK-1799, Denmark.
| | - Stefano Moscatello
- National Research Council CNR-Istituto di Biologia Agroambientale e Forestale, Viale Marconi 2, 05010 Porano, TR, Italy.
| | - Alberto Battistelli
- National Research Council CNR-Istituto di Biologia Agroambientale e Forestale, Viale Marconi 2, 05010 Porano, TR, Italy.
| | - Paolo Trost
- Department of Pharmacy and Biotechnology FABIT, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy.
| | - Domenico Lafiandra
- Department of Agricultural and Forestry Sciences DAFNE, University of Tuscia, Via S. Camillo de Lellis, SNC, 01100 Viterbo, Italy.
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30
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Zhu F, Bertoft E, Li G. Morphological, Thermal, and Rheological Properties of Starches from Maize Mutants Deficient in Starch Synthase III. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:6539-6545. [PMID: 27523327 DOI: 10.1021/acs.jafc.6b01265] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Morphological, thermal, and rheological properties of starches from maize mutants deficient in starch synthase III (SSIII) with a common genetic background (W64A) were studied and compared with the wild type. SSIII deficiency reduced granule size of the starches from 16.7 to ∼11 μm (volume-weighted mean). Thermal analysis showed that SSIII deficiency decreased the enthalpy change of starch during gelatinization. Steady shear analysis showed that SSIII deficiency decreased the consistency coefficient and yield stress during steady shearing, whereas additional deficiency in granule-bound starch synthase (GBSS) increased these values. Dynamic oscillatory analysis showed that SSIII deficiency decreased G' at 90 °C during heating and increased it when the paste was cooled to 25 °C at 40 Hz during a frequency sweep. Additional GBSS deficiency further decreased the G'. Structural and compositional bases responsible for these changes in physical properties of the starches are discussed. This study highlighted the relationship between SSIII and some physicochemical properties of maize starch.
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Affiliation(s)
- Fan Zhu
- School of Chemical Sciences, University of Auckland , Private Bag 92019, Auckland 1142, New Zealand
| | - Eric Bertoft
- Department of Food Science and Nutrition, University of Minnesota , 1334 Eckles Avenue, St. Paul, Minnesota 55455, United States
| | - Guantian Li
- School of Chemical Sciences, University of Auckland , Private Bag 92019, Auckland 1142, New Zealand
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31
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Nakagami T, Yoshihara H, Nakamura T, Utsumi Y, Sawada T, Fujita N, Satoh H, Nakamura Y. Biochemical analysis of new type mutants of japonica rice that accumulate water-soluble α-glucans in the endosperm but retain full starch debranching enzyme activities. STARCH-STARKE 2016. [DOI: 10.1002/star.201600159] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Tsuyoshi Nakagami
- Faculty of Bioresource Sciences; Akita Prefectural University; Shimoshinjo-Nakano Akita Japan
| | - Hiroki Yoshihara
- Faculty of Bioresource Sciences; Akita Prefectural University; Shimoshinjo-Nakano Akita Japan
| | - Tetsuhiro Nakamura
- Faculty of Agriculture, Institute of Genetic Resources; Kyushu University; Fukuoka Japan
| | - Yoshinori Utsumi
- Faculty of Bioresource Sciences; Akita Prefectural University; Shimoshinjo-Nakano Akita Japan
| | - Takayuki Sawada
- Faculty of Bioresource Sciences; Akita Prefectural University; Shimoshinjo-Nakano Akita Japan
| | - Naoko Fujita
- Faculty of Bioresource Sciences; Akita Prefectural University; Shimoshinjo-Nakano Akita Japan
| | - Hikaru Satoh
- Faculty of Agriculture, Institute of Genetic Resources; Kyushu University; Fukuoka Japan
| | - Yasunori Nakamura
- Faculty of Bioresource Sciences; Akita Prefectural University; Shimoshinjo-Nakano Akita Japan
- Akita Natural Science Laboratory, Tennoh; Katagami Akita Japan
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32
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Abstract
Starch-rich crops form the basis of our nutrition, but plants have still to yield all their secrets as to how they make this vital substance. Great progress has been made by studying both crop and model systems, and we approach the point of knowing the enzymatic machinery responsible for creating the massive, insoluble starch granules found in plant tissues. Here, we summarize our current understanding of these biosynthetic enzymes, highlighting recent progress in elucidating their specific functions. Yet, in many ways we have only scratched the surface: much uncertainty remains about how these components function together and are controlled. We flag-up recent observations suggesting a significant degree of flexibility during the synthesis of starch and that previously unsuspected non-enzymatic proteins may have a role. We conclude that starch research is not yet a mature subject and that novel experimental and theoretical approaches will be important to advance the field.
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Affiliation(s)
- Barbara Pfister
- Department of Biology, ETH Zurich, 8092, Zurich, Switzerland
| | - Samuel C Zeeman
- Department of Biology, ETH Zurich, 8092, Zurich, Switzerland.
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33
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Kobayashi T, Sasaki S, Utsumi Y, Fujita N, Umeda K, Sawada T, Kubo A, Abe JI, Colleoni C, Ball S, Nakamura Y. Comparison of Chain-Length Preferences and Glucan Specificities of Isoamylase-Type α-Glucan Debranching Enzymes from Rice, Cyanobacteria, and Bacteria. PLoS One 2016; 11:e0157020. [PMID: 27309534 PMCID: PMC4911114 DOI: 10.1371/journal.pone.0157020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 05/22/2016] [Indexed: 01/30/2023] Open
Abstract
It has been believed that isoamylase (ISA)-type α-glucan debranching enzymes (DBEs) play crucial roles not only in α-glucan degradation but also in the biosynthesis by affecting the structure of glucans, although molecular basis on distinct roles of the individual DBEs has not fully understood. In an attempt to relate the roles of DBEs to their chain-length specificities, we analyzed the chain-length distribution of DBE enzymatic reaction products by using purified DBEs from various sources including rice, cyanobacteria, and bacteria. When DBEs were incubated with phytoglycogen, their chain-length specificities were divided into three groups. First, rice endosperm ISA3 (OsISA3) and Eschericia coli GlgX (EcoGlgX) almost exclusively debranched chains having degree of polymerization (DP) of 3 and 4. Second, OsISA1, Pseudomonas amyloderamosa ISA (PsaISA), and rice pullulanase (OsPUL) could debranch a wide range of chains of DP≧3. Third, both cyanobacteria ISAs, Cyanothece ATCC 51142 ISA (CytISA) and Synechococcus elongatus PCC7942 ISA (ScoISA), showed the intermediate chain-length preference, because they removed chains of mainly DP3-4 and DP3-6, respectively, while they could also react to chains of DP5-10 and 7–13 to some extent, respectively. In contrast, all these ISAs were reactive to various chains when incubated with amylopectin. In addition to a great variation in chain-length preferences among various ISAs, their activities greatly differed depending on a variety of glucans. Most strikingly, cyannobacteria ISAs could attack branch points of pullulan to a lesser extent although no such activity was found in OsISA1, OsISA3, EcoGlgX, and PsaISA. Thus, the present study shows the high possibility that varied chain-length specificities of ISA-type DBEs among sources and isozymes are responsible for their distinct functions in glucan metabolism.
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Affiliation(s)
- Taiki Kobayashi
- Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-Nakano, Akita, Japan
| | - Satoshi Sasaki
- Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-Nakano, Akita, Japan
| | - Yoshinori Utsumi
- Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-Nakano, Akita, Japan
| | - Naoko Fujita
- Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-Nakano, Akita, Japan
| | - Kazuhiro Umeda
- Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-Nakano, Akita, Japan
| | - Takayuki Sawada
- Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-Nakano, Akita, Japan
| | - Akiko Kubo
- Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-Nakano, Akita, Japan
| | - Jun-ichi Abe
- Faculty of Agriculture, Kagoshima University, Kagoshima, Japan
| | - Christophe Colleoni
- Unité de Glycobiologie Structurale et Fonctionnelle, Université des Sciences et Technologies de Lille, Villeneuve d’Ascq, France
| | - Steven Ball
- Unité de Glycobiologie Structurale et Fonctionnelle, Université des Sciences et Technologies de Lille, Villeneuve d’Ascq, France
| | - Yasunori Nakamura
- Faculty of Bioresource Sciences, Akita Prefectural University, Shimoshinjo-Nakano, Akita, Japan
- Akita Natural Science Laboratory, Tennoh, Katagami, Akita, Japan
- * E-mail:
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34
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Crofts N, Abe N, Oitome NF, Matsushima R, Hayashi M, Tetlow IJ, Emes MJ, Nakamura Y, Fujita N. Amylopectin biosynthetic enzymes from developing rice seed form enzymatically active protein complexes. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:4469-82. [PMID: 25979995 PMCID: PMC4507757 DOI: 10.1093/jxb/erv212] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Amylopectin is a highly branched, organized cluster of glucose polymers, and the major component of rice starch. Synthesis of amylopectin requires fine co-ordination between elongation of glucose polymers by soluble starch synthases (SSs), generation of branches by branching enzymes (BEs), and removal of misplaced branches by debranching enzymes (DBEs). Among the various isozymes having a role in amylopectin biosynthesis, limited numbers of SS and BE isozymes have been demonstrated to interact via protein-protein interactions in maize and wheat amyloplasts. This study investigated whether protein-protein interactions are also found in rice endosperm, as well as exploring differences between species. Gel permeation chromatography of developing rice endosperm extracts revealed that all 10 starch biosynthetic enzymes analysed were present at larger molecular weights than their respective monomeric sizes. SSIIa, SSIIIa, SSIVb, BEI, BEIIb, and PUL co-eluted at mass sizes >700kDa, and SSI, SSIIa, BEIIb, ISA1, PUL, and Pho1 co-eluted at 200-400kDa. Zymogram analyses showed that SSI, SSIIIa, BEI, BEIIa, BEIIb, ISA1, PUL, and Pho1 eluted in high molecular weight fractions were active. Comprehensive co-immunoprecipitation analyses revealed associations of SSs-BEs, and, among BE isozymes, BEIIa-Pho1, and pullulanase-type DBE-BEI interactions. Blue-native-PAGE zymogram analyses confirmed the glucan-synthesizing activity of protein complexes. These results suggest that some rice starch biosynthetic isozymes are physically associated with each other and form active protein complexes. Detailed analyses of these complexes will shed light on the mechanisms controlling the unique branch and cluster structure of amylopectin, and the physicochemical properties of starch.
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Affiliation(s)
- Naoko Crofts
- Department of Biological Production, Akita Prefectural University, 241-438 Kaidobata-Nishi, Shimoshinjo-Nakano, Akita city, Akita 010-0195, Japan
| | - Natsuko Abe
- Department of Biological Production, Akita Prefectural University, 241-438 Kaidobata-Nishi, Shimoshinjo-Nakano, Akita city, Akita 010-0195, Japan
| | - Naoko F Oitome
- Department of Biological Production, Akita Prefectural University, 241-438 Kaidobata-Nishi, Shimoshinjo-Nakano, Akita city, Akita 010-0195, Japan
| | - Ryo Matsushima
- Institute of Plant Sciences and Resources, Okayama University, Chuo 2-20-1, Kurashiki city, Okayama 710-0046, Japan
| | - Mari Hayashi
- Department of Biological Production, Akita Prefectural University, 241-438 Kaidobata-Nishi, Shimoshinjo-Nakano, Akita city, Akita 010-0195, Japan
| | - Ian J Tetlow
- Department of Molecular and Cellular Biology, College of Biological Science, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Michael J Emes
- Department of Molecular and Cellular Biology, College of Biological Science, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Yasunori Nakamura
- Department of Biological Production, Akita Prefectural University, 241-438 Kaidobata-Nishi, Shimoshinjo-Nakano, Akita city, Akita 010-0195, Japan
| | - Naoko Fujita
- Department of Biological Production, Akita Prefectural University, 241-438 Kaidobata-Nishi, Shimoshinjo-Nakano, Akita city, Akita 010-0195, Japan
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35
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Schwarte S, Wegner F, Havenstein K, Groth D, Steup M, Tiedemann R. Sequence variation, differential expression, and divergent evolution in starch-related genes among accessions of Arabidopsis thaliana. PLANT MOLECULAR BIOLOGY 2015; 87:489-519. [PMID: 25663508 DOI: 10.1007/s11103-015-0293-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 01/26/2015] [Indexed: 06/04/2023]
Abstract
Transitory starch metabolism is a nonlinear and highly regulated process. It originated very early in the evolution of chloroplast-containing cells and is largely based on a mosaic of genes derived from either the eukaryotic host cell or the prokaryotic endosymbiont. Initially located in the cytoplasm, starch metabolism was rewired into plastids in Chloroplastida. Relocation was accompanied by gene duplications that occurred in most starch-related gene families and resulted in subfunctionalization of the respective gene products. Starch-related isozymes were then evolutionary conserved by constraints such as internal starch structure, posttranslational protein import into plastids and interactions with other starch-related proteins. 25 starch-related genes in 26 accessions of Arabidopsis thaliana were sequenced to assess intraspecific diversity, phylogenetic relationships, and modes of selection. Furthermore, sequences derived from additional 80 accessions that are publicly available were analyzed. Diversity varies significantly among the starch-related genes. Starch synthases and phosphorylases exhibit highest nucleotide diversities, while pyrophosphatases and debranching enzymes are most conserved. The gene trees are most compatible with a scenario of extensive recombination, perhaps in a Pleistocene refugium. Most genes are under purifying selection, but disruptive selection was inferred for a few genes/substitutiones. To study transcript levels, leaves were harvested throughout the light period. By quantifying the transcript levels and by analyzing the sequence of the respective accessions, we were able to estimate whether transcript levels are mainly determined by genetic (i.e., accession dependent) or physiological (i.e., time dependent) parameters. We also identified polymorphic sites that putatively affect pattern or the level of transcripts.
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Affiliation(s)
- Sandra Schwarte
- Evolutionary Biology, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Strasse 24-25, Building 26, 14476, Potsdam, Germany,
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36
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Kang G, Peng X, Wang L, Yang Y, Shao R, Xie Y, Ma D, Wang C, Guo T, Zhu Y. Ultrastructural observation of mesophyll cells and temporal expression profiles of the genes involved in transitory starch metabolism in flag leaves of wheat after anthesis. PHYSIOLOGIA PLANTARUM 2015; 153:12-29. [PMID: 24853500 DOI: 10.1111/ppl.12233] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 04/27/2014] [Indexed: 05/08/2023]
Abstract
Transitory starch in cereal plant leaves is synthesized during the day and remobilized at night to provide a carbon source for growth and grain filling, but its mechanistic basis is still poorly understood. The objective of this study is to explore the regulatory mechanism for starch biosynthesis and degradation in plant source organs. Using transmission electron microscopy, we observed that during the day after anthesis, starch granules in mesophyll cells of wheat flag leaves accumulated in chloroplasts and the number of starch granules gradually decreased with wheat leaf growth. During the night, starch granules synthesized in chloroplasts during the day were completely or partially degraded. The transcript levels of 26 starch synthesis-related genes and 16 starch breakdown-related genes were further measured using quantitative real-time reverse transcription polymerase chain reaction. Expression profile analysis revealed that starch metabolism genes were clustered into two groups based on their temporal expression patterns. The genes in the first group were highly expressed and presumed to play crucial roles in starch metabolism. The genes in the other group were not highly expressed in flag leaves and may have minor functions in starch metabolism in leaf tissue. The functions of most of these genes in leaves were further discussed. The starch metabolism-related genes that are predominantly expressed in wheat flag leaves differ from those expressed in wheat grain, indicating that two different pathways for starch metabolism operate in these tissues. This provides specific information on the molecular mechanisms of transitory starch metabolism in higher plants.
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Affiliation(s)
- Guozhang Kang
- The Collaborative Innovation Center of Henan Food Crops, Henan Agricultural University, Zhengzhou, 450002, China
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37
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Zheng Y, Wang Z. The cereal starch endosperm development and its relationship with other endosperm tissues and embryo. PROTOPLASMA 2015; 252:33-40. [PMID: 25123370 DOI: 10.1007/s00709-014-0687-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 08/01/2014] [Indexed: 05/28/2023]
Abstract
The cereal starch endosperm is the central part of endosperm, and it is rich in starch and protein which are the important resources for human food. The starch and protein are separately accumulated in starch granules and protein bodies. Content and configuration of starch granules and protein bodies affect the quality of the starch endosperm. The development of starch endosperm is mediated by genes, enzymes, and hormones, and it also has a close relationship with other endosperm tissues and embryo. This paper reviews the latest investigations on the starch endosperm and will provide some useful information for the future researches on the development of cereal endosperm.
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Affiliation(s)
- Yankun Zheng
- College of Agriculture, Yangzhou University, Yangzhou, 225009, Jiangsu, China
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38
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Park YJ, Nishikawa T, Tomooka N, Nemoto K. Molecular characterization of an isoamylase 1-type starch debranching enzyme (DBEI) in grain amaranth (Amaranthus cruentus L.). Mol Biol Rep 2014; 41:7857-64. [PMID: 25167854 DOI: 10.1007/s11033-014-3679-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 08/19/2014] [Indexed: 10/24/2022]
Abstract
The purpose of this study was to characterize the molecular profile of a starch debranching enzyme (DBE) in grain amaranth. A cDNA clone that encodes a putative DBE was isolated from amaranth perisperm and then sequenced. This amaranth DBE appears to be an ISA1-type DBE (DBEI), based on its substrate specificity and the sequence similarity between the 2,391-bp cDNA clone and ISA1 s from potato and Arabidopsis. The mature DBEI of amaranth consists of 796 amino acids (90.5 kDa). We analyzed the transcript levels of the DBEI gene in amaranth seeds during various developmental stages and in plant tissues by qRT-PCR and RT-PCR analyses. The transcript levels of the DBEI gene rapidly increased at the middle stage of seed maturation. This result indicates that the enzyme encoded by the amaranth DBEI gene plays an important role in starch accumulation throughout the seed during the middle stage of seed development. We detected DBEI transcripts in storage and non-storage tissues. At the six-leaf stage, there were high levels of the DBEI transcripts in leaves, petioles, and the stem, and low levels in the root. Therefore, we suggest that the DBEI expression is not specific to non-storage and/or storage tissues. This summary of the basic characteristics of the DBEI gene will contribute to further studies on starch biosynthesis in Amaranthus.
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Affiliation(s)
- Young-Jun Park
- Graduate School of Agriculture, Shinshu University, 8304 Minamiminowa, Nagano, 399-4598, Japan,
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39
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Sim L, Beeren SR, Findinier J, Dauvillée D, Ball SG, Henriksen A, Palcic MM. Crystal structure of the Chlamydomonas starch debranching enzyme isoamylase ISA1 reveals insights into the mechanism of branch trimming and complex assembly. J Biol Chem 2014; 289:22991-23003. [PMID: 24993830 DOI: 10.1074/jbc.m114.565044] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The starch debranching enzymes isoamylase 1 and 2 (ISA1 and ISA2) are known to exist in a large complex and are involved in the biosynthesis and crystallization of starch. It is suggested that the function of the complex is to remove misplaced branches of growing amylopectin molecules, which would otherwise prevent the association and crystallization of adjacent linear chains. Here, we investigate the function of ISA1 and ISA2 from starch producing alga Chlamydomonas. Through complementation studies, we confirm that the STA8 locus encodes for ISA2 and sta8 mutants lack the ISA1·ISA2 heteromeric complex. However, mutants retain a functional dimeric ISA1 that is able to partly sustain starch synthesis in vivo. To better characterize ISA1, we have overexpressed and purified ISA1 from Chlamydomonas reinhardtii (CrISA1) and solved the crystal structure to 2.3 Å and in complex with maltoheptaose to 2.4 Å. Analysis of the homodimeric CrISA1 structure reveals a unique elongated structure with monomers connected end-to-end. The crystal complex reveals details about the mechanism of branch binding that explains the low activity of CrISA1 toward tightly spaced branches and reveals the presence of additional secondary surface carbohydrate binding sites.
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Affiliation(s)
- Lyann Sim
- Carlsberg Laboratory, Gamle Carlsberg Vej 10, DK-1799 Copenhagen V, Denmark and.
| | - Sophie R Beeren
- Carlsberg Laboratory, Gamle Carlsberg Vej 10, DK-1799 Copenhagen V, Denmark and
| | - Justin Findinier
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR 8576 CNRS-USTL, Bâtiment C9, Cité Scientifique, F-59655 Villeneuve d'Ascq, France
| | - David Dauvillée
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR 8576 CNRS-USTL, Bâtiment C9, Cité Scientifique, F-59655 Villeneuve d'Ascq, France
| | - Steven G Ball
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR 8576 CNRS-USTL, Bâtiment C9, Cité Scientifique, F-59655 Villeneuve d'Ascq, France
| | - Anette Henriksen
- Carlsberg Laboratory, Gamle Carlsberg Vej 10, DK-1799 Copenhagen V, Denmark and
| | - Monica M Palcic
- Carlsberg Laboratory, Gamle Carlsberg Vej 10, DK-1799 Copenhagen V, Denmark and
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40
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Streb S, Zeeman SC. Replacement of the endogenous starch debranching enzymes ISA1 and ISA2 of Arabidopsis with the rice orthologs reveals a degree of functional conservation during starch synthesis. PLoS One 2014; 9:e92174. [PMID: 24642810 PMCID: PMC3958451 DOI: 10.1371/journal.pone.0092174] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Accepted: 02/20/2014] [Indexed: 11/19/2022] Open
Abstract
This study tested the interchangeability of enzymes in starch metabolism between dicotyledonous and monocotyledonous plant species. Amylopectin - a branched glucose polymer - is the major component of starch and is responsible for its semi-crystalline property. Plants synthesize starch with distinct amylopectin structures, varying between species and tissues. The structure determines starch properties, an important characteristic for cooking and nutrition, and for the industrial uses of starch. Amylopectin synthesis involves at least three enzyme classes: starch synthases, branching enzymes and debranching enzymes. For all three classes, several enzyme isoforms have been identified. However, it is not clear which enzyme(s) are responsible for the large diversity of amylopectin structures. Here, we tested whether the specificities of the debranching enzymes (ISA1 and ISA2) are major determinants of species-dependent differences in amylopectin structure by replacing the dicotyledonous Arabidopsis isoamylases (AtISA1 and AtISA2) with the monocotyledonous rice (Oryza sativa) isoforms. We demonstrate that the ISA1 and ISA2 are sufficiently well conserved between these species to form heteromultimeric chimeric Arabidopsis/rice isoamylase enzymes. Furthermore, we were able to reconstitute the endosperm-specific rice OsISA1 homomultimeric complex in Arabidopsis isa1isa2 mutants. This homomultimer was able to facilitate normal rates of starch synthesis. The resulting amylopectin structure had small but significant differences in comparison to wild-type Arabidopsis amylopectin. This suggests that ISA1 and ISA2 have a conserved function between plant species with a major role in facilitating the crystallization of pre-amylopectin synthesized by starch synthases and branching enzymes, but also influencing the final structure of amylopectin.
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Affiliation(s)
- Sebastian Streb
- Institute for Agricultural Sciences, Department of Biology, ETH Zurich, Zurich, Switzerland
- * E-mail:
| | - Samuel C. Zeeman
- Institute for Agricultural Sciences, Department of Biology, ETH Zurich, Zurich, Switzerland
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41
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Wang K, Henry RJ, Gilbert RG. Causal Relations Among Starch Biosynthesis, Structure, and Properties. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s40362-014-0016-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Malinova I, Mahlow S, Alseekh S, Orawetz T, Fernie AR, Baumann O, Steup M, Fettke J. Double knockout mutants of Arabidopsis grown under normal conditions reveal that the plastidial phosphorylase isozyme participates in transitory starch metabolism. PLANT PHYSIOLOGY 2014; 164:907-21. [PMID: 24302650 PMCID: PMC3912115 DOI: 10.1104/pp.113.227843] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 12/01/2013] [Indexed: 05/20/2023]
Abstract
In leaves of two starch-related single-knockout lines lacking either the cytosolic transglucosidase (also designated as disproportionating enzyme 2, DPE2) or the maltose transporter (MEX1), the activity of the plastidial phosphorylase isozyme (PHS1) is increased. In both mutants, metabolism of starch-derived maltose is impaired but inhibition is effective at different subcellular sites. Two constitutive double knockout mutants were generated (designated as dpe2-1×phs1a and mex1×phs1b) both lacking functional PHS1. They reveal that in normally grown plants, the plastidial phosphorylase isozyme participates in transitory starch degradation and that the central carbon metabolism is closely integrated into the entire cell biology. All plants were grown either under continuous illumination or in a light-dark regime. Both double mutants were compromised in growth and, compared with the single knockout plants, possess less average leaf starch when grown in a light-dark regime. Starch and chlorophyll contents decline with leaf age. As revealed by transmission electron microscopy, mesophyll cells degrade chloroplasts, but degradation is not observed in plants grown under continuous illumination. The two double mutants possess similar but not identical phenotypes. When grown in a light-dark regime, mesophyll chloroplasts of dpe2-1×phs1a contain a single starch granule but under continuous illumination more granules per chloroplast are formed. The other double mutant synthesizes more granules under either growth condition. In continuous light, growth of both double mutants is similar to that of the parental single knockout lines. Metabolite profiles and oligoglucan patterns differ largely in the two double mutants.
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43
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Powell PO, Sullivan MA, Sweedman MC, Stapleton DI, Hasjim J, Gilbert RG. Extraction, isolation and characterisation of phytoglycogen from su-1 maize leaves and grain. Carbohydr Polym 2014; 101:423-31. [DOI: 10.1016/j.carbpol.2013.09.061] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 08/13/2013] [Accepted: 09/18/2013] [Indexed: 10/26/2022]
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44
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Lin Q, Facon M, Putaux JL, Dinges JR, Wattebled F, D'Hulst C, Hennen-Bierwagen TA, Myers AM. Function of isoamylase-type starch debranching enzymes ISA1 and ISA2 in the Zea mays leaf. THE NEW PHYTOLOGIST 2013; 200:1009-1021. [PMID: 23952574 DOI: 10.1111/nph.12446] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 07/08/2013] [Indexed: 06/02/2023]
Abstract
Conserved isoamylase-type starch debranching enzymes (ISAs), including the catalytic ISA1 and noncatalytic ISA2, are major starch biosynthesis determinants. Arabidopsis thaliana leaves require ISA1 and ISA2 for physiological function, whereas endosperm starch is near normal with only ISA1. ISA functions were characterized in maize (Zea mays) leaves to determine whether species-specific distinctions in ISA1 primary structure, or metabolic differences in tissues, are responsible for the differing ISA2 requirement. Genetic methods provided lines lacking ISA1 or ISA2. Biochemical analyses characterized ISA activities in mutant tissues. Starch content, granule morphology, and amylopectin fine structure were determined. Three ISA activity forms were observed in leaves, two ISA1/ISA2 heteromultimers and one ISA1 homomultimer. ISA1 homomultimer activity existed in mutants lacking ISA2. Mutants without ISA2 differed in leaf starch content, granule morphology, and amylopectin structure compared with nonmutants or lines lacking both ISA1 and ISA2. The data imply that both the ISA1 homomultimer and ISA1/ISA2 heteromultimer function in the maize leaf. The ISA1 homomultimer is present and functions in the maize leaf. Evolutionary divergence between monocots and dicots probably explains the ability of ISA1 to function as a homomultimer in maize leaves, in contrast to other species where the ISA1/ISA2 heteromultimer is the only active form.
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Affiliation(s)
- Qiaohui Lin
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
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45
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Facon M, Lin Q, Azzaz AM, Hennen-Bierwagen TA, Myers AM, Putaux JL, Roussel X, D’Hulst C, Wattebled F. Distinct functional properties of isoamylase-type starch debranching enzymes in monocot and dicot leaves. PLANT PHYSIOLOGY 2013; 163:1363-75. [PMID: 24027240 PMCID: PMC3813656 DOI: 10.1104/pp.113.225565] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 09/06/2013] [Indexed: 05/20/2023]
Abstract
Isoamylase-type starch debranching enzymes (ISA) play important roles in starch biosynthesis in chloroplast-containing organisms, as shown by the strict conservation of both catalytically active ISA1 and the noncatalytic homolog ISA2. Functional distinctions exist between species, although they are not understood yet. Numerous plant tissues require both ISA1 and ISA2 for normal starch biosynthesis, whereas monocot endosperm and leaf exhibit nearly normal starch metabolism without ISA2. This study took in vivo and in vitro approaches to determine whether organism-specific physiology or evolutionary divergence between monocots and dicots is responsible for distinctions in ISA function. Maize (Zea mays) ISA1 was expressed in Arabidopsis (Arabidopsis thaliana) lacking endogenous ISA1 or lacking both native ISA1 and ISA2. The maize protein functioned in Arabidopsis leaves to support nearly normal starch metabolism in the absence of any native ISA1 or ISA2. Analysis of recombinant enzymes showed that Arabidopsis ISA1 requires ISA2 as a partner for enzymatic function, whereas maize ISA1 was active by itself. The electrophoretic mobility of recombinant and native maize ISA differed, suggestive of posttranslational modifications in vivo. Sedimentation equilibrium measurements showed recombinant maize ISA1 to be a dimer, in contrast to previous gel permeation data that estimated the molecular mass as a tetramer. These data demonstrate that evolutionary divergence between monocots and dicots is responsible for the distinctions in ISA1 function.
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Cenci U, Chabi M, Ducatez M, Tirtiaux C, Nirmal-Raj J, Utsumi Y, Kobayashi D, Sasaki S, Suzuki E, Nakamura Y, Putaux JL, Roussel X, Durand-Terrasson A, Bhattacharya D, Vercoutter-Edouart AS, Maes E, Arias MC, Palcic M, Sim L, Ball SG, Colleoni C. Convergent evolution of polysaccharide debranching defines a common mechanism for starch accumulation in cyanobacteria and plants. THE PLANT CELL 2013; 25:3961-75. [PMID: 24163312 PMCID: PMC3877820 DOI: 10.1105/tpc.113.118174] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Starch, unlike hydrosoluble glycogen particles, aggregates into insoluble, semicrystalline granules. In photosynthetic eukaryotes, the transition to starch accumulation occurred after plastid endosymbiosis from a preexisting cytosolic host glycogen metabolism network. This involved the recruitment of a debranching enzyme of chlamydial pathogen origin. The latter is thought to be responsible for removing misplaced branches that would otherwise yield a water-soluble polysaccharide. We now report the implication of starch debranching enzyme in the aggregation of semicrystalline granules of single-cell cyanobacteria that accumulate both glycogen and starch-like polymers. We show that an enzyme of analogous nature to the plant debranching enzyme but of a different bacterial origin was recruited for the same purpose in these organisms. Remarkably, both the plant and cyanobacterial enzymes have evolved through convergent evolution, showing novel yet identical substrate specificities from a preexisting enzyme that originally displayed the much narrower substrate preferences required for glycogen catabolism.
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Affiliation(s)
- Ugo Cenci
- Université des Sciences et Technologies de Lille, Unité de Glycobiologie Structurale et Fonctionnelle, Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique, Cité Scientifique, 59655 Villeneuve d’Ascq cedex, France
| | - Malika Chabi
- Université des Sciences et Technologies de Lille, Unité de Glycobiologie Structurale et Fonctionnelle, Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique, Cité Scientifique, 59655 Villeneuve d’Ascq cedex, France
| | - Mathieu Ducatez
- Université des Sciences et Technologies de Lille, Unité de Glycobiologie Structurale et Fonctionnelle, Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique, Cité Scientifique, 59655 Villeneuve d’Ascq cedex, France
| | - Catherine Tirtiaux
- Université des Sciences et Technologies de Lille, Unité de Glycobiologie Structurale et Fonctionnelle, Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique, Cité Scientifique, 59655 Villeneuve d’Ascq cedex, France
| | - Jennifer Nirmal-Raj
- Université des Sciences et Technologies de Lille, Unité de Glycobiologie Structurale et Fonctionnelle, Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique, Cité Scientifique, 59655 Villeneuve d’Ascq cedex, France
| | - Yoshinori Utsumi
- Department of Biological Production, Akita Prefectural University, Akita 010-0195, Japan
| | - Daiki Kobayashi
- Department of Biological Production, Akita Prefectural University, Akita 010-0195, Japan
| | - Satoshi Sasaki
- Department of Biological Production, Akita Prefectural University, Akita 010-0195, Japan
| | - Eiji Suzuki
- Department of Biological Production, Akita Prefectural University, Akita 010-0195, Japan
| | - Yasunori Nakamura
- Department of Biological Production, Akita Prefectural University, Akita 010-0195, Japan
| | - Jean-Luc Putaux
- Centre de Recherches sur Les Macromolécules Végétales (Centre National de la Recherche Scientifique), F-38041 Grenoble cedex 9, France (affiliated with Université Joseph Fourier and Member of Institut de Chimie Moléculaire de Grenoble and Insitut Carnot PolyNat)
| | - Xavier Roussel
- Université des Sciences et Technologies de Lille, Unité de Glycobiologie Structurale et Fonctionnelle, Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique, Cité Scientifique, 59655 Villeneuve d’Ascq cedex, France
| | - Amandine Durand-Terrasson
- Centre de Recherches sur Les Macromolécules Végétales (Centre National de la Recherche Scientifique), F-38041 Grenoble cedex 9, France (affiliated with Université Joseph Fourier and Member of Institut de Chimie Moléculaire de Grenoble and Insitut Carnot PolyNat)
| | - Debashish Bhattacharya
- Department of Ecology, Evolution, and Natural Resources, Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, New Jersey 08901
| | - Anne-Sophie Vercoutter-Edouart
- Université des Sciences et Technologies de Lille, Unité de Glycobiologie Structurale et Fonctionnelle, Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique, Cité Scientifique, 59655 Villeneuve d’Ascq cedex, France
| | - Emmanuel Maes
- Université des Sciences et Technologies de Lille, Unité de Glycobiologie Structurale et Fonctionnelle, Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique, Cité Scientifique, 59655 Villeneuve d’Ascq cedex, France
| | - Maria Cecilia Arias
- Université des Sciences et Technologies de Lille, Unité de Glycobiologie Structurale et Fonctionnelle, Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique, Cité Scientifique, 59655 Villeneuve d’Ascq cedex, France
| | | | - Lyann Sim
- Carlsberg Laboratory, Copenhagen V DK-1799, Denmark
| | - Steven G. Ball
- Université des Sciences et Technologies de Lille, Unité de Glycobiologie Structurale et Fonctionnelle, Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique, Cité Scientifique, 59655 Villeneuve d’Ascq cedex, France
| | - Christophe Colleoni
- Université des Sciences et Technologies de Lille, Unité de Glycobiologie Structurale et Fonctionnelle, Unité Mixte de Recherche 8576, Centre National de la Recherche Scientifique, Cité Scientifique, 59655 Villeneuve d’Ascq cedex, France
- Address correspondence to
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Sundberg M, Pfister B, Fulton D, Bischof S, Delatte T, Eicke S, Stettler M, Smith SM, Streb S, Zeeman SC. The heteromultimeric debranching enzyme involved in starch synthesis in Arabidopsis requires both isoamylase1 and isoamylase2 subunits for complex stability and activity. PLoS One 2013; 8:e75223. [PMID: 24098685 PMCID: PMC3787081 DOI: 10.1371/journal.pone.0075223] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 08/10/2013] [Indexed: 11/18/2022] Open
Abstract
Isoamylase-type debranching enzymes (ISAs) play an important role in determining starch structure. Amylopectin – a branched polymer of glucose – is the major component of starch granules and its architecture underlies the semi-crystalline nature of starch. Mutants of several species lacking the ISA1-subclass of isoamylase are impaired in amylopectin synthesis. Consequently, starch levels are decreased and an aberrant soluble glucan (phytoglycogen) with altered branch lengths and branching pattern accumulates. Here we use TAP (tandem affinity purification) tagging to provide direct evidence in Arabidopsis that ISA1 interacts with its homolog ISA2. No evidence for interaction with other starch biosynthetic enzymes was found. Analysis of the single mutants shows that each protein is destabilised in the absence of the other. Co-expression of both ISA1 and ISA2 Escherichia coli allowed the formation of the active recombinant enzyme and we show using site-directed mutagenesis that ISA1 is the catalytic subunit. The presence of the active isoamylase alters glycogen biosynthesis in E. coli, resulting in colonies that stain more starch-like with iodine. However, analysis of the glucans reveals that rather than producing an amylopectin like substance, cells expressing the active isoamylase still accumulate small amounts of glycogen together with a population of linear oligosaccharides that stain strongly with iodine. We conclude that for isoamylase to promote amylopectin synthesis it needs to act on a specific precursor (pre-amylopectin) generated by the combined actions of plant starch synthase and branching enzyme isoforms and when presented with an unsuitable substrate (i.e. E. coli glycogen) it simply degrades it.
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Affiliation(s)
| | | | - Daniel Fulton
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | | | | | - Simona Eicke
- Department of Biology, ETH Zurich, Zurich, Switzerland
| | | | - Steven M. Smith
- School of Chemistry and Biochemistry, University of Western Australia, Crawley, Western Australia, Australia
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Abstract
Starch is the major non-structural carbohydrate in plants. It serves as an important store of carbon that fuels plant metabolism and growth when they are unable to photosynthesise. This storage can be in leaves and other green tissues, where it is degraded during the night, or in heterotrophic tissues such as roots, seeds and tubers, where it is stored over longer time periods. Arabidopsis accumulates starch in many of its tissues, but mostly in its leaves during the day. It has proven to be a powerful genetic system for discovering how starch is synthesised and degraded, and new proteins and processes have been discovered. Such work has major significance for our starch crops, whose yield and quality could be improved by the application of this knowledge. Research into Arabidopsis starch metabolism has begun to reveal how its daily turnover is integrated into the rest of metabolism and adapted to the environmental conditions. Furthermore, Arabidopsis mutant lines deficient in starch metabolism have been employed as tools to study other biological processes ranging from sugar sensing to gravitropism and flowering time control. This review gives a detailed account of the use of Arabidopsis to study starch metabolism. It describes the major discoveries made and presents an overview of our understanding today, together with some as-yet unresolved questions.
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Affiliation(s)
- Sebastian Streb
- Institute of Agricultural Sciences, Department of Biology, ETH
Zurich, Universitätstrasse 2, Zurich, Switzerland
| | - Samuel C. Zeeman
- Institute of Agricultural Sciences, Department of Biology, ETH
Zurich, Universitätstrasse 2, Zurich, Switzerland
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Streb S, Zeeman SC. Starch metabolism in Arabidopsis. THE ARABIDOPSIS BOOK 2012; 10:e0160. [PMID: 23393426 DOI: 10.199/tab.e0160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Starch is the major non-structural carbohydrate in plants. It serves as an important store of carbon that fuels plant metabolism and growth when they are unable to photosynthesise. This storage can be in leaves and other green tissues, where it is degraded during the night, or in heterotrophic tissues such as roots, seeds and tubers, where it is stored over longer time periods. Arabidopsis accumulates starch in many of its tissues, but mostly in its leaves during the day. It has proven to be a powerful genetic system for discovering how starch is synthesised and degraded, and new proteins and processes have been discovered. Such work has major significance for our starch crops, whose yield and quality could be improved by the application of this knowledge. Research into Arabidopsis starch metabolism has begun to reveal how its daily turnover is integrated into the rest of metabolism and adapted to the environmental conditions. Furthermore, Arabidopsis mutant lines deficient in starch metabolism have been employed as tools to study other biological processes ranging from sugar sensing to gravitropism and flowering time control. This review gives a detailed account of the use of Arabidopsis to study starch metabolism. It describes the major discoveries made and presents an overview of our understanding today, together with some as-yet unresolved questions.
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Affiliation(s)
- Sebastian Streb
- Institute of Agricultural Sciences, Department of Biology, ETH Zurich, Universitätstrasse 2, Zurich, Switzerland
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Potent inhibition of starch-synthase by Tris-type buffers is responsible for the perpetuation of the primer myth for starch biosynthesis. Carbohydr Res 2012; 355:28-34. [DOI: 10.1016/j.carres.2012.04.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 04/19/2012] [Accepted: 04/20/2012] [Indexed: 11/22/2022]
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