scholarly journals Expression ofE. coliglycogen branching enzyme in anArabidopsismutant devoid of endogenous starch branching enzymes induces the synthesis of starch-like polyglucans

2015 ◽  
Author(s):  
Laura Boyer ◽  
Xavier Roussel ◽  
Adeline Courseaux ◽  
Ofilia Mvundza Ndjindji ◽  
Christine Lancelon-Pin ◽  
...  
Keyword(s):  
Double Mutant ◽  
Starch Synthesis ◽  
Water Soluble ◽  
Relative Importance ◽  
Branching Enzyme ◽  
Limited Impact ◽  
Debranching Enzymes ◽  
Branching Enzymes ◽  
Plant Storage ◽  
Glycogen Branching Enzyme

Starch synthesis requires several enzymatic activities including branching enzymes (BEs) responsible for the formation of α(1→6) linkages. Distribution and number of these linkages are further controlled by debranching enzymes (DBEs) that cleave some of them, rendering the polyglucan water-insoluble and semi-crystalline. Although the activity of BEs and DBEs is mandatory to sustain normal starch synthesis, the relative importance of each in the establishment of the plant storage polyglucan (i.e. water-insolubility, crystallinity, presence of amylose) is still debated. Here, we have substituted the activity of BEs inArabidopsiswith that of theEscherichia coliglycogen branching enzyme (GlgB). The latter is the BE counterpart in the metabolism of glycogen, a highly branched water-soluble and amorphous storage polyglucan. GlgB was expressed in thebe2 be3double mutant ofArabidopsisthat is devoid of BE activity and consequently free of starch. The synthesis of a water-insoluble, partly crystalline, amylose-containing starch-like polyglucan was restored in GlgB-expressing plants, suggesting that BEs origin only have a limited impact on establishing essential characteristics of starch. Moreover, the balance between branching and debranching is crucial for the synthesis of starch, as an excess of branching activity results in the formation of highly branched, water-soluble, poorly crystalline polyglucan.

scholarly journals Maize endosperm-specific transcription factors O2 and PBF network the regulation of protein and starch synthesis

2016 ◽  
Vol 113 (39) ◽  
pp. 10842-10847 ◽  
Author(s):  
Zhiyong Zhang ◽  
Xixi Zheng ◽  
Jun Yang ◽  
Joachim Messing ◽  
Yongrui Wu
Keyword(s):  
Transcription Factors ◽  
Double Mutant ◽  
Starch Content ◽  
Starch Synthesis ◽  
Starch Synthase ◽  
Maize Endosperm ◽  
Protein Levels ◽  
Pyruvate Orthophosphate Dikinase ◽  
Branching Enzymes ◽  
Critical Components

The maize endosperm-specific transcription factors opaque2 (O2) and prolamine-box binding factor (PBF) regulate storage protein zein genes. We show that they also control starch synthesis. The starch content in the PbfRNAi and o2 mutants was reduced by ∼5% and 11%, respectively, compared with normal genotypes. In the double-mutant PbfRNAi;o2, starch was decreased by 25%. Transcriptome analysis reveals that >1,000 genes were affected in each of the two mutants and in the double mutant; these genes were mainly enriched in sugar and protein metabolism. Pyruvate orthophosphate dikinase 1 and 2 (PPDKs) and starch synthase III (SSIII) are critical components in the starch biosynthetic enzyme complex. The expression of PPDK1, PPDK2, and SSIII and their protein levels are further reduced in the double mutants as compared with the single mutants. When the promoters of these genes were analyzed, we found a prolamine box and an O2 box that can be additively transactivated by PBF and O2. Starch synthase IIa (SSIIa, encoding another starch synthase for amylopectin) and starch branching enzyme 1 (SBEI, encoding one of the two main starch branching enzymes) are not directly regulated by PBF and O2, but their protein levels are significantly decreased in the o2 mutant and are further decreased in the double mutant, indicating that o2 and PbfRNAi may affect the levels of some other transcription factor(s) or mRNA regulatory factor(s) that in turn would affect the transcript and protein levels of SSIIa and SBEI. These findings show that three important traits—nutritional quality, calories, and yield—are linked through the same transcription factors.

scholarly journals Soluble Starch Synthase Enzymes in Cereals: An Updated Review

Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1983
Author(s):  
Ahsan Irshad ◽  
Huijun Guo ◽  
Shoaib Ur Rehman ◽  
Xueqing Wang ◽  
Chaojie Wang ◽  
...  
Keyword(s):  
Structural Characteristics ◽  
Starch Synthesis ◽  
Soluble Starch ◽  
Starch Synthase ◽  
Cereal Crops ◽  
Starch Granules ◽  
Starch Structure ◽  
Debranching Enzymes ◽  
Branching Enzymes ◽  
Starch Yield

Cereal crops have starch in their endosperm, which has provided calories to humans and livestock since the dawn of civilization to the present day. Starch is one of the important biological factors which is contributing to the yield of cereal crops. Starch is synthesized by different enzymes, but starch structure and amount are mainly determined by the activities of starch synthase enzymes (SS) with the involvement of starch branching enzymes (SBEs) and debranching enzymes (DBEs). Six classes of SSs are found in Arabidopsis and are designated as soluble SSI-V, and non-soluble granule bound starch synthase (GBSS). Soluble SSs are important for starch yield considering their role in starch biosynthesis in cereal crops, and the activities of these enzymes determine the structure of starch and the physical properties of starch granules. One of the unique characteristics of starch structure is elongated glucan chains within amylopectin, which is by SSs through interactions with other starch biosynthetic enzymes (SBEs and DBEs). Additionally, soluble SSs also have conserved domains with phosphorylation sites that may be involved in regulating starch metabolism and formation of heteromeric SS complexes. This review presents an overview of soluble SSs in cereal crops and includes their functional and structural characteristics in relation to starch synthesis.

scholarly journals Starch metabolism in leaves.

2008 ◽  
Vol 55 (3) ◽  
pp. 435-445 ◽  
Author(s):  
Sławomir Orzechowski
Keyword(s):  
Translational Regulation ◽  
Higher Plants ◽  
Current Knowledge ◽  
Starch Synthesis ◽  
Starch Degradation ◽  
Starch Metabolism ◽  
Debranching Enzymes ◽  
Storage Carbohydrate ◽  
Branching Enzymes ◽  
Diphosphate Glucose

Starch is the most abundant storage carbohydrate produced in plants. The initiation of transitory starch synthesis and degradation in plastids depends mainly on diurnal cycle, post-translational regulation of enzyme activity and starch phosphorylation. For the proper structure of starch granule the activities of all starch synthase isoenzymes, branching enzymes and debranching enzymes are needed. The intensity of starch biosynthesis depends mainly on the activity of AGPase (adenosine 5'-diphosphate glucose pyrophosphorylase). The key enzymes in starch degradation are beta-amylase, isoamylase 3 and disproportionating enzyme. However, it should be underlined that there are some crucial differences in starch metabolism between heterotrophic and autotrophic tissues, e.g. is the ability to build multiprotein complexes responsible for biosynthesis and degradation of starch granules in chloroplasts. The observed huge progress in understanding of starch metabolism was possible mainly due to analyses of the complete Arabidopsis and rice genomes and of numerous mutants with altered starch metabolism in leaves. The aim of this paper is to review current knowledge on transient starch metabolism in higher plants.

scholarly journals Synthesis of Hyperbranched Glycoconjugates by the Combined Action of Potato Phosphorylase and Glycogen Branching Enzyme from Deinococcus geothermalis

Polymers ◽  
2012 ◽  
Vol 4 (1) ◽  
pp. 674-690 ◽  
Author(s):  
Jeroen van der Vlist ◽  
Martin Faber ◽  
Lizette Loen ◽  
Teunis J. Dijkman ◽  
Lia A. T. W. Asri ◽  
...  
Keyword(s):  
Branching Enzyme ◽  
Deinococcus Geothermalis ◽  
Combined Action ◽  
Glycogen Branching Enzyme

Neonatal type IV glycogen storage disease associated with “null” mutations in glycogen branching enzyme 1

2004 ◽  
Vol 145 (5) ◽  
pp. 705-709 ◽  
Author(s):  
Andreas R. Janecke ◽  
Susanne Dertinger ◽  
Uwe-Peter Ketelsen ◽  
Lothar Bereuter ◽  
Burkhard Simma ◽  
...  
Keyword(s):  
Glycogen Storage Disease ◽  
Storage Disease ◽  
Glycogen Storage ◽  
Branching Enzyme ◽  
Type Iv ◽  
Glycogen Branching Enzyme

scholarly journals GLC3 and GHA1 of Saccharomyces cerevisiae are allelic and encode the glycogen branching enzyme.

1992 ◽  
Vol 12 (1) ◽  
pp. 22-29 ◽  
Author(s):  
D W Rowen ◽  
M Meinke ◽  
D C LaPorte
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Glycogen Metabolism ◽  
Striking Difference ◽  
Branching Enzyme ◽  
Yeast Saccharomyces Cerevisiae ◽  
Storage Carbohydrate ◽  
Functional Product ◽  
Cloned Gene ◽  
Transposon Insertions ◽  
Glycogen Branching Enzyme

In the yeast Saccharomyces cerevisiae, glycogen serves as a major storage carbohydrate. In a previous study, mutants with altered glycogen metabolism were isolated on the basis of the altered iodine-staining properties of colonies. We found that when glycogen produced by strains carrying the glc-1p (previously called gha1-1) mutation is stained with iodine, the absorption spectrum resembles that of starch rather than that of glycogen, suggesting that this mutation might reduce the level of branching in the glycogen particles. Indeed, glycogen branching activity was undetectable in extracts from a glc3-1p strain but was elevated in strains which expressed GLC3 from a high-copy-number plasmid. These observations suggest that GLC3 encodes the glycogen branching enzyme. In contrast to glc3-1p, the glc3-4 mutation greatly reduces the ability of yeast to accumulate glycogen. These mutations appear to be allelic despite the striking difference in the phenotypes which they produce. The GLC3 clone complemented both glc3-1p and glc3-4. Deletions and transposon insertions in this clone had parallel effects on its ability to complement glc3-1p and glc3-4. Finally, a fragment of the cloned gene was able to direct the repair of both glc3-1p and glc3-4. Disruption of GLC3 yielded the glycogen-deficient phenotype, indicating that glycogen deficiency is the null phenotype. The glc3-1p allele appears to encode a partially functional product, since it is dominant over glc3-4 but recessive to GLC3. These observations suggest that the ability to introduce branches into glycogen greatly increases the ability of the cell to accumulate that polysaccharide. Northern (RNA) blot analysis identified a single mRNA of 2,300 nucleotides that increased in abundance ca. 20-fold as the culture approached stationary phase. It thus appears that the expression of GLC3 is regulated, probably at the level of transcription.

Glycogen branching enzyme deficiency in adult polyglucosan body disease

1993 ◽  
Vol 33 (1) ◽  
pp. 88-93 ◽  
Author(s):  
Claudio Bruno ◽  
Serenella Servidei ◽  
Sara Shanske ◽  
George Karpati ◽  
Stirling Carpenter ◽  
...  
Keyword(s):  
Enzyme Deficiency ◽  
Branching Enzyme ◽  
Polyglucosan Body ◽  
Adult Polyglucosan Body Disease ◽  
Glycogen Branching Enzyme
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