Nature of the Periplastidial Pathway of Starch Synthesis in the Cryptophyte Guillardia theta

ABSTRACT The nature of the periplastidial pathway of starch biosynthesis was investigated with the model cryptophyte Guillardia theta. The storage polysaccharide granules were shown to be composed of both amylose and amylopectin fractions with a chain length distribution and crystalline organization very similar to those of starch from green algae and land plants. Most starch granules displayed a shape consistent with biosynthesis occurring around the pyrenoid through the rhodoplast membranes. A protein with significant similarity to the amylose-synthesizing granule-bound starch synthase 1 from green plants was found as the major polypeptide bound to the polysaccharide matrix. N-terminal sequencing of the mature protein proved that the precursor protein carries a nonfunctional transit peptide in its bipartite topogenic signal sequence which is cleaved without yielding transport of the enzyme across the two inner plastid membranes. The enzyme was shown to display similar affinities for ADP and UDP-glucose, while the V max measured with UDP-glucose was twofold higher. The granule-bound starch synthase from Guillardia theta was demonstrated to be responsible for the synthesis of long glucan chains and therefore to be the functional equivalent of the amylose-synthesizing enzyme of green plants. Preliminary characterization of the starch pathway suggests that Guillardia theta utilizes a UDP-glucose-based pathway to synthesize starch.

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Competition between Granule Bound Starch Synthase and Starch Branching Enzyme in Starch Biosynthesis

Rice ◽

10.1186/s12284-019-0353-3 ◽

2019 ◽

Vol 12 (1) ◽

Cited By ~ 3

Author(s):

Huaxin Han ◽

Chuantian Yang ◽

Jihui Zhu ◽

Lixia Zhang ◽

Yeming Bai ◽

...

Keyword(s):

Functional Properties ◽

Length Distribution ◽

Soluble Starch ◽

Starch Biosynthesis ◽

Starch Synthase ◽

Size Exclusion ◽

Rice Starch ◽

Rice Varieties ◽

Chain Length Distribution ◽

Granule Bound Starch Synthase

Abstract Background Starch branching enzymes (SBE) and granule-bound starch synthase (GBSS) are two important enzymes for starch biosynthesis. SBE mainly contributes to the formation of side branches, and GBSS mainly contributes for the synthesis of amylose molecules. However, there are still gaps in the understanding of possible interactions between SBE and GBSS. Results Nineteen natural rice varieties with amylose contents up to 28% were used. The molecular structure, in the form of the chain-length distribution (CLDs, the distribution of the number of monomer units in each branch) was measured after enzymatic debranching, using fluorophore-assisted carbohydrate electrophoresis for amylopectin and size- exclusion chromatography for amylose. The resulting distributions were fitted to two mathematical models based on the underlying biosynthetic processes, which express the CLDs in terms of parameters reflecting relevant enzyme activities. Conclusions Finding statistically valid correlations between the values of these parameters showed that GBSSI and SBEI compete for substrates during rice starch biosynthesis, and synthesis of amylose short chains involves several enzymes including GBSSI, SBE and SSS (soluble starch synthase). Since the amylose CLD is important for a number of functional properties such as digestion rate, this knowledge is potentially useful for developing varieties with improved functional properties.

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Pathway of Cytosolic Starch Synthesis in the Model Glaucophyte Cyanophora paradoxa

Eukaryotic Cell ◽

10.1128/ec.00373-07 ◽

2007 ◽

Vol 7 (2) ◽

pp. 247-257 ◽

Cited By ~ 34

Author(s):

Charlotte Plancke ◽

Christophe Colleoni ◽

Philippe Deschamps ◽

David Dauvillée ◽

Yasunori Nakamura ◽

...

Keyword(s):

Starch Synthesis ◽

Length Distribution ◽

Soluble Starch ◽

Land Plant ◽

Starch Synthase ◽

Cyanophora Paradoxa ◽

Chain Length Distribution ◽

Photosynthetic Eukaryotes ◽

A Chain

ABSTRACT The nature of the cytoplasmic pathway of starch biosynthesis was investigated in the model glaucophyte Cyanophora paradoxa. The storage polysaccharide granules are shown to be composed of both amylose and amylopectin fractions, with a chain length distribution and crystalline organization similar to those of green algae and land plant starch. A preliminary characterization of the starch pathway demonstrates that Cyanophora paradoxa contains several UDP-glucose-utilizing soluble starch synthase activities related to those of the Rhodophyceae. In addition, Cyanophora paradoxa synthesizes amylose with a granule-bound starch synthase displaying a preference for UDP-glucose. A debranching enzyme of isoamylase specificity and multiple starch phosphorylases also are evidenced in the model glaucophyte. The picture emerging from our biochemical and molecular characterizations consists of the presence of a UDP-glucose-based pathway similar to that recently proposed for the red algae, the cryptophytes, and the alveolates. The correlative presence of isoamylase and starch among photosynthetic eukaryotes is discussed.

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Natural variation in rice starch synthase IIa affects enzyme and starch properties

Functional Plant Biology ◽

10.1071/fp04009 ◽

2004 ◽

Vol 31 (7) ◽

pp. 671 ◽

Cited By ~ 108

Author(s):

Takayuki Umemoto ◽

Noriaki Aoki ◽

Hongxuan Lin ◽

Yasunori Nakamura ◽

Naoyoshi Inouchi ◽

...

Keyword(s):

Amino Acid ◽

Natural Variation ◽

Oryza Sativa L ◽

Length Distribution ◽

Starch Synthase ◽

Rice Starch ◽

Nucleotide Polymorphisms ◽

Cultivated Rice ◽

Chain Length Distribution ◽

Starch Properties

The natural variation in starch synthase IIa (SSIIa) of rice (Oryza sativa L.) was characterised using near-isogenic lines (NILs). SSIIa is a candidate for the alk gene regulating the alkali disintegration of rice grains, since both genes are genetically mapped at the same position on chromosome 6 and related to starch properties. In this study, we report that the alkali-susceptible cultivar Nipponbare lacked SSIIa activity in endosperm. However, the activity was detected with NILs having the alk allele of alkali-tolerant Kasalath. SSIIa protein was present even in Nipponbare endosperm, but it was not associated with starch granules at the milky stage of endosperm. Three single-nucleotide polymorphisms (SNPs) predicting amino acid substitutions existed between the cDNA sequences of SSIIa of Nipponbare and Kasalath were genotyped with 65 rice cultivars and four wild relatives of cultivated rice. The results obtained explain the potential importance of two of the amino acid residues for starch association of rice SSIIa. An analysis of the chain-length distribution of β-limit dextrin of amylopectin showed that without SSIIa activity, the relative number of A-chains (the short chains without branches) increased and that of B1-chains (the short chains with branches) decreased. This suggests that, given the SSIIa defect, short A-chains could not reach a sufficient length for branching enzymes to act on them to produce B1-chains.

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Analysis of the Functional Interaction of Arabidopsis Starch Synthase and Branching Enzyme Isoforms Reveals that the Cooperative Action of SSI and BEs Results in Glucans with Polymodal Chain Length Distribution Similar to Amylopectin

PLoS ONE ◽

10.1371/journal.pone.0102364 ◽

2014 ◽

Vol 9 (7) ◽

pp. e102364 ◽

Cited By ~ 26

Author(s):

Henrike Brust ◽

Tanja Lehmann ◽

Christophe D'Hulst ◽

Joerg Fettke

Keyword(s):

Chain Length ◽

Length Distribution ◽

Starch Synthase ◽

Branching Enzyme ◽

Functional Interaction ◽

Chain Length Distribution ◽

Cooperative Action ◽

Enzyme Isoforms

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Expression of bacterial starch-binding domains in Arabidopsis increases starch granule size

Functional Plant Biology ◽

10.1071/fp05277 ◽

2006 ◽

Vol 33 (3) ◽

pp. 257 ◽

Cited By ~ 6

Author(s):

Crispin A. Howitt ◽

Sadequr Rahman ◽

Matthew K. Morell

Keyword(s):

Starch Granule ◽

Starch Content ◽

Starch Synthesis ◽

Length Distribution ◽

Renewable Resource ◽

Granule Size ◽

Parental Line ◽

In Planta ◽

Chain Length Distribution ◽

Binding Domains

Starch is a readily renewable resource that is very widely used for food and industrial purposes; however, greater variation in the functional properties of starch would further extend the use of this biodegradable polymer. Genetic engineering may provide a way to produce designer starches that have the desired properties. Starch-binding domains (SBD) from bacterial enzymes that catabolise starches have the ability to bind two helices of starch and thus have the potential to crosslink starch and / or to be used as anchors for other enzymes that can modify starch properties. In a first step towards novel modification of starch we have investigated the effect of expressing SBDs, singly and in tandem, in planta, and targeting them to the chloroplast in the model plant Arabidopsis thaliana (L.) Heynh. Transgenic plants that contained the SBD from the cyclomaltodextrin glucanotransferase (CGTase) of Thermoanaerobacterium thermosulfurigenes in the chloroplast were produced in both the wild type and the starch excess mutant (sex 1-1) backgrounds. Analysis of starch isolated from the chloroplasts of these lines revealed no significant changes in the amylose : amylopectin ratio, the chain-length distribution of debranched amylopectin or the gelatinisation temperature when compared to the parental line. However, significant changes were observed in the starch granule size with the plants expressing the construct having larger granules. The effect was more pronounced in the sex 1-1 background, and expression of two starch-binding domains linked in tandem had an even greater effect. Despite the starch granules being larger in lines expressing the starch-binding domain, no difference was seen in the starch content of the leaves when compared to parental lines. As the presence of the SBDs in the starch granule only altered granule size, and not other granule properties, they may provide an ideal anchor for targeting starch-modifying enzymes to the site of starch synthesis. This will allow the development of novel modifications of starch during synthesis.

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Single-nucleotide polymorphisms in rice starch synthase IIa that alter starch gelatinisation and starch association of the enzyme

Functional Plant Biology ◽

10.1071/fp04214 ◽

2005 ◽

Vol 32 (9) ◽

pp. 763 ◽

Cited By ~ 103

Author(s):

Takayuki Umemoto ◽

Noriaki Aoki

Keyword(s):

Amino Acid ◽

Single Nucleotide Polymorphisms ◽

Oryza Sativa L ◽

Length Distribution ◽

Branch Length ◽

Starch Synthase ◽

Rice Starch ◽

Nucleotide Polymorphisms ◽

Single Nucleotide ◽

Chain Length Distribution

The starch synthase IIa (SSIIa) gene of rice (Oryza sativa L.) has been shown to be the alk gene that controls alkali disintegration of rice grains, although the effects of naturally occurring alk mutant alleles on enzyme function have yet to be determined. We genotyped 60 rice cultivars for two single-nucleotide polymorphisms (SNPs) in rice SSIIa, including one that results in an amino acid substitution. Incorporating data for three other SNPs previously genotyped in rice SSIIa, five haplotypes were found. We analysed the association of these SSIIa haplotypes with the chain-length distribution of amylopectin, the gelatinisation temperature of rice flour, the alkali spreading score, and the starch association of the enzyme. It was determined that two SNPs resulting in amino acid changes close to the C-terminus most likely alter SSIIa both in terms of activity and starch granule association. This in turn alters the branch-length distribution of amylopectin and the gelatinisation properties of starch.

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Wheat genome specific granule-bound starch synthase I differentially influence grain starch synthesis

Carbohydrate Polymers ◽

10.1016/j.carbpol.2014.08.004 ◽

2014 ◽

Vol 114 ◽

pp. 87-94 ◽

Cited By ~ 10

Author(s):

Geetika Ahuja ◽

Sarita Jaiswal ◽

Pierre Hucl ◽

Ravindra N. Chibbar

Keyword(s):

Starch Synthesis ◽

Starch Synthase ◽

Wheat Genome ◽

Grain Starch ◽

Specific Granule ◽

Granule Bound Starch Synthase

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The Heterotrophic Dinoflagellate Crypthecodinium cohnii Defines a Model Genetic System To Investigate Cytoplasmic Starch Synthesis

Eukaryotic Cell ◽

10.1128/ec.00461-07 ◽

2008 ◽

Vol 7 (5) ◽

pp. 872-880 ◽

Cited By ~ 23

Author(s):

Philippe Deschamps ◽

Delphine Guillebeault ◽

Jimi Devassine ◽

David Dauvillée ◽

Sophie Haebel ◽

...

Keyword(s):

Starch Synthesis ◽

Length Distribution ◽

Genetic System ◽

Soluble Starch ◽

Land Plant ◽

Heterotrophic Dinoflagellate ◽

Chain Length Distribution ◽

Crypthecodinium Cohnii ◽

A Chain

ABSTRACT The nature of the cytoplasmic pathway of starch biosynthesis was investigated in the model heterotrophic dinoflagellate Crypthecodinium cohnii. The storage polysaccharide granules were shown to be composed of both amylose and amylopectin fractions with a chain length distribution and crystalline organization very similar to those of green algae and land plant starch. Preliminary characterization of the starch pathway demonstrated that C. cohnii contains multiple forms of soluble starch synthases and one major 110-kDa granule-bound starch synthase. All purified enzymes displayed a marked substrate preference for UDP-glucose. At variance with most other microorganisms, the accumulation of starch in the dinoflagellate occurs during early and mid-log phase, with little or no synthesis witnessed when approaching stationary phase. In order to establish a genetic system allowing the study of cytoplasmic starch metabolism in eukaryotes, we describe the isolation of marker mutations and the successful selection of random recombinant populations after homothallic crosses.

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