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Collins HM, Betts NS, Dockter C, Berkowitz O, Braumann I, Cuesta-Seijo JA, Skadhauge B, Whelan J, Bulone V, Fincher GB. Genes That Mediate Starch Metabolism in Developing and Germinated Barley Grain. FRONTIERS IN PLANT SCIENCE 2021; 12:641325. [PMID: 33732278 PMCID: PMC7959180 DOI: 10.3389/fpls.2021.641325] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 01/27/2021] [Indexed: 05/21/2023]
Abstract
Starch is synthesized in the endosperm of developing barley grain, where it functions as the primary source of stored carbohydrate. In germinated grain these starch reserves are hydrolyzed to small oligosaccharides and glucose, which are transported to the embryo to support the growth of the developing seedling. Some of the mobilized glucose is transiently stored as starch in the scutellum of germinated grain. These processes are crucial for early seedling vigor, which is a key determinant of crop productivity and global food security. Several starch synthases (SS), starch-branching enzymes (SBEs), and starch debranching enzymes (isoamylases, ISA), together with a limit dextrinase (LD), have been implicated in starch synthesis from nucleotide-sugar precursors. Starch synthesis occurs both in the developing endosperm and in the scutellum of germinated grain. For the complete depolymerization of starch to glucose, α-amylase (Amy), β-amylase (Bmy), isoamylase (ISA), limit dextrinase (LD), and α-glucosidase (AGL) are required. Most of these enzymes are encoded by gene families of up to 10 or more members. Here RNA-seq transcription data from isolated tissues of intact developing and germinated barley grain have allowed us to identify the most important, specific gene family members for each of these processes in vivo and, at the same time, we have defined in detail the spatio-temporal coordination of gene expression in different tissues of the grain. A transcript dataset for 81,280 genes is publicly available as a resource for investigations into other cellular and biochemical processes that occur in the developing grain from 6 days after pollination.
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Affiliation(s)
- Helen M. Collins
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, Australia
| | - Natalie S. Betts
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, Australia
| | | | - Oliver Berkowitz
- School of Life Sciences and ARC Centre of Excellence in Plant Energy Biology, La Trobe University, Bundoora, VIC, Australia
| | | | | | | | - James Whelan
- School of Life Sciences and ARC Centre of Excellence in Plant Energy Biology, La Trobe University, Bundoora, VIC, Australia
| | - Vincent Bulone
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, Australia
- Adelaide Glycomics, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, Australia
| | - Geoffrey B. Fincher
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, Australia
- *Correspondence: Geoffrey B. Fincher,
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Liu DR, Huang WX, Cai XL. Oligomerization of rice granule-bound starch synthase 1 modulates its activity regulation. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 210:141-50. [PMID: 23849121 DOI: 10.1016/j.plantsci.2013.05.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 05/16/2013] [Accepted: 05/17/2013] [Indexed: 05/23/2023]
Abstract
Granule-bound starch synthase 1 (GBSS1) is responsible for amylose synthesis in cereals, and this enzyme is regulated at the transcriptional and post-transcriptional levels. In this study, we show that GBSS1 from Oryza sativa L. (OsGBSS1) can form oligomers in rice endosperm, and oligomerized OsGBSS1 exhibits much higher specific enzymatic activity than the monomer. A monomer-oligomer transition equilibrium for OsGBSS1 occurs in the endosperm during development. Redox potential is a key factor affecting the oligomer percentage as well as the enzymatic activity of OsGBSS1. Adenosine diphosphate glucose, the direct donor of glucose, also impacts OsGBSS1 oligomerization in a concentration-dependent manner. OsGBSS1 oligomerization is influenced by phosphorylation status, which was strongly enhanced by Mitogen-activated protein kinase (MAPK) and ATP treatment and was sharply weakened by protein phosphatase (PPase) treatment. The activity of OsGBSS1 affects the ratio of amylose to amylopectin and therefore the eating quality of rice. Understanding the regulation of OsGBSS1 activity may lead to the improvement of rice eating quality.
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Affiliation(s)
- De-Rui Liu
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
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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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Zhang X, Szydlowski N, Delvallé D, D'Hulst C, James MG, Myers AM. Overlapping functions of the starch synthases SSII and SSIII in amylopectin biosynthesis in Arabidopsis. BMC PLANT BIOLOGY 2008; 8:96. [PMID: 18811962 PMCID: PMC2566982 DOI: 10.1186/1471-2229-8-96] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Accepted: 09/23/2008] [Indexed: 05/18/2023]
Abstract
BACKGROUND The biochemical mechanisms that determine the molecular architecture of amylopectin are central in plant biology because they allow long-term storage of reduced carbon. Amylopectin structure imparts the ability to form semi-crystalline starch granules, which in turn provides its glucose storage function. The enzymatic steps of amylopectin biosynthesis resemble those of the soluble polymer glycogen, however, the reasons for amylopectin's architectural distinctions are not clearly understood. The multiplicity of starch biosynthetic enzymes conserved in plants likely is involved. For example, amylopectin chain elongation in plants involves five conserved classes of starch synthase (SS), whereas glycogen biosynthesis typically requires only one class of glycogen synthase. RESULTS Null mutations were characterized in AtSS2, which codes for SSII, and mutant lines were compared to lines lacking SSIII and to an Atss2, Atss3 double mutant. Loss of SSII did not affect growth rate or starch quantity, but caused increased amylose/amylopectin ratio, increased total amylose, and deficiency in amylopectin chains with degree of polymerization (DP) 12 to DP28. In contrast, loss of both SSII and SSIII caused slower plant growth and dramatically reduced starch content. Extreme deficiency in DP12 to DP28 chains occurred in the double mutant, far more severe than the summed changes in SSII- or SSIII-deficient plants lacking only one of the two enzymes. CONCLUSION SSII and SSIII have partially redundant functions in determination of amylopectin structure, and these roles cannot be substituted by any other conserved SS, specifically SSI, GBSSI, or SSIV. Even though SSIII is not required for the normal abundance of glucan chains of DP12 to DP18, the enzyme clearly is capable of functioning in production such chains. The role of SSIII in producing these chains cannot be detected simply by analysis of an individual mutation. Competition between different SSs for binding to substrate could in part explain the specific distribution of glucan chains within amylopectin.
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Affiliation(s)
- Xiaoli Zhang
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, USA
- The Ohio State University, Center for Biostatistics, M200 Starling Loving Hall, 320 W. 10th Avenue, Columbus, OH 43210, USA
| | - Nicolas Szydlowski
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR8576 du CNRS, IFR 147, Bâtiment C9, Université des Sciences et Technologies de Lille, 59655 Villeneuve d'Ascq Cedex, France
| | - David Delvallé
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR8576 du CNRS, IFR 147, Bâtiment C9, Université des Sciences et Technologies de Lille, 59655 Villeneuve d'Ascq Cedex, France
| | - Christophe D'Hulst
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR8576 du CNRS, IFR 147, Bâtiment C9, Université des Sciences et Technologies de Lille, 59655 Villeneuve d'Ascq Cedex, France
| | - Martha G James
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, USA
| | - Alan M Myers
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, USA
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Tetlow IJ. Understanding storage starch biosynthesis in plants: a means to quality improvement. ACTA ACUST UNITED AC 2006. [DOI: 10.1139/b06-089] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The many varied uses of starch in food and industrial applications often requires an understanding of its physicochemical properties and the detailed variations in granule structure that underpin these properties. The ability to manipulate storage starch structures depends on understanding the biosynthetic pathway, and in particular, how the many components of the pathway are coordinated and regulated. This article presents a current overview of starch structure and the known enzymes involved in the synthesis of the granule, with an emphasis on how current knowledge on the regulation of the pathway in cereals and other crops may be applied to the production of different functional starches.
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Affiliation(s)
- Ian J. Tetlow
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada (e-mail: )
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Ball SG, Morell MK. From bacterial glycogen to starch: understanding the biogenesis of the plant starch granule. ANNUAL REVIEW OF PLANT BIOLOGY 2003; 54:207-33. [PMID: 14502990 DOI: 10.1146/annurev.arplant.54.031902.134927] [Citation(s) in RCA: 441] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plants, green algae, and cyanobacteria synthesize storage polysaccharides by a similar ADPglucose-based pathway. Plant starch metabolism can be distinguished from that of bacterial glycogen by the presence of multiple forms of enzyme activities for each step of the pathway. This multiplicity does not coincide with any functional redundancy, as each form has seemingly acquired a distinctive and conserved role in starch metabolism. Comparisons of phenotypes generated by debranching enzyme-defective mutants in Escherichia coli and plants suggest that enzymes previously thought to be involved in polysaccharide degradation have been recruited during evolution to serve a particular purpose in starch biosynthesis. Speculations have been made that link this recruitment to the appearance of semicrystalline starch in photosynthetic eukaryotes. Besides the common core pathway, other enzymes of malto-oligosaccharide metabolism are required for normal starch metabolism. However, according to the genetic and physiological system under study, these enzymes may have acquired distinctive roles.
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Affiliation(s)
- Steven G Ball
- Laboratoire de Chimie Biologique, UMR 8576 du CNRS, Université des Sciences et Technologies de Lille, Bâtiment C9-Cité Scientifique, France.
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Cao H, James MG, Myers AM. Purification and characterization of soluble starch synthases from maize endosperm. Arch Biochem Biophys 2000; 373:135-46. [PMID: 10620332 DOI: 10.1006/abbi.1999.1547] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study identified and characterized the soluble starch synthase of maize endosperm that was initially revealed as the SSII activity peak in anion exchange chromatography (J. L. Ozbun et al. (1971) Plant Physiol. 48, 765-769). At least six different genes coding for starch synthases are expressed in maize, although previously it was not known which of these is responsible for the SSII activity peak. The enzyme activity in the SSII peak was neutralized to a large extent by antibodies raised against the product of the Du1 gene, but was not affected by antibodies specific for the other highly expressed soluble starch synthase, zSSI, or for the zSSIIa or zSSIIb isoforms. These data provide direct evidence that Du1 codes for the starch synthase responsible for the SSII activity peak. This starch synthase was purified approximately 350-fold from endosperm extracts. The following enzymatic properties of the SSII activity were determined: temperature optimum, thermostability, pH effects, K(m) for different glucan primers and the glucosyl unit donor ADPGlc, V(max) using various primers, and stimulation by citrate. These properties were compared to those of zSSI purified over 1600-fold from maize endosperm by a parallel procedure. The major differences between the two enzymes were that the SSII activity displayed higher K(m) values for ADPGlc, a distinct temperature range for maximal activity, and different relative activities toward specific exogenous substrates. The purified SSI and SSII activities both were shown to be capable of elongating maltooligosaccharide primers in vitro.
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Affiliation(s)
- H Cao
- Department of Biochemistry, Iowa State University, 2110 Molecular Biology Building, Ames, Iowa, 50011, USA
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