Control of Starch Composition and Structure through Substrate Supply in the Monocellular Alga

Koornhuyse, Nathalie van den; Libessart, Nathalie; Delrue, Brigitte; Zabawinski, Christophe; Decq, André; Iglesias, Alberto A.; Carton, Anne; Preiss, Jack; Ball, Steven

doi:10.1074/jbc.271.27.16281

Cited by 93 publications

(60 citation statements)

References 34 publications

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“…Starch accumulation is severely affected in plants that are deficient in ADGase activity. This has been shown in Arabidopsis leaves (Lin et al, 1988a, b), maize endosperm (Weaver et al, 1972), pea cotyledons (Smith et al, 1989), Chlamydomonas (Van den Koornhuyse et al, 1996), and in tubers of potato plants expressing antisense constructs of an ADGase gene (Muller-Rober et al, 1992). The Arabidopsis adg2 mutant has only~5% ADGase activity but accumulates~40% of wild-type starch levels (Lin et al, 1988b).…”

Section: Introductionmentioning

confidence: 84%

Characterization of ADG1, an Arabidopsis locus encoding for ADPG pyrophosphorylase small subunit, demonstrates that the presence of the small subunit is required for large subunit stability

Wang

Lue

et al. 1998

The Plant Journal

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SummaryTwo mutants of Arabidopsis have been isolated that affect ADPG pyrophosphorylase (ADGase) activity. Previously, it has been shown that ADG2 encodes the large subunit of ADGase. This study characterizes the adg1 mutant phenotype and ADG1 gene structure. RNA blot analyses indicate that the adg1-1 mutant accumulates transcripts encoding both the large and small subunits of ADGase, while the adg1-2 mutant accumulates only large subunit transcripts. RFLP analysis and complementation of adg1 mutants with the ADGase small subunit gene demonstrate that ADG1 encodes the small subunit. Sequence analysis indicates that adg1-1 represents a missense mutation within the gene. Western blot analysis confirms that adg1 mutants contain neither the large nor the small subunit proteins, suggesting that the presence of functional small subunits is required for large subunit stability.

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Section: Introductionmentioning

confidence: 84%

Characterization of ADG1, an Arabidopsis locus encoding for ADPG pyrophosphorylase small subunit, demonstrates that the presence of the small subunit is required for large subunit stability

Wang

Lue

et al. 1998

The Plant Journal

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“…Thus, amylose may be more readily synthesized in sex4 granules than in wildtype or sex1 granules. However, other factors such as the supply of substrates are also known to influence amylose synthesis (Van den Koornhuyse et al, 1996;Clarke et al, 1999) and may also contribute to the observed differences.…”

Section: Amylose Content Of Leaf Starchmentioning

confidence: 99%

Starch Synthesis in Arabidopsis. Granule Synthesis, Composition, and Structure

et al. 2002

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The aim of this work was to characterize starch synthesis, composition, and granule structure in Arabidopsis leaves. First, the potential role of starch-degrading enzymes during starch accumulation was investigated. To discover whether simultaneous synthesis and degradation of starch occurred during net accumulation, starch was labeled by supplying 14 CO 2 to intact, photosynthesizing plants. Release of this label from starch was monitored during a chase period in air, using different light intensities to vary the net rate of starch synthesis. No release of label was detected unless there was net degradation of starch during the chase. Similar experiments were performed on a mutant line (dbe1) that accumulates the soluble polysaccharide, phytoglycogen. Label was not released from phytoglycogen during the chase indicating that, even when in a soluble form, glucan is not appreciably degraded during accumulation. Second, the effect on starch composition of growth conditions and mutations causing starch accumulation was studied. An increase in starch content correlated with an increased amylose content of the starch and with an increase in the ratio of granule-bound starch synthase to soluble starch synthase activity. Third, the structural organization and morphology of Arabidopsis starch granules was studied. The starch granules were birefringent, indicating a radial organization of the polymers, and x-ray scatter analyses revealed that granules contained alternating crystalline and amorphous lamellae with a periodicity of 9 nm. Granules from the wild type and the high-starch mutant sex1 were flattened and discoid, whereas those of the high-starch mutant sex4 were larger and more rounded. These larger granules contained "growth rings" with a periodicity of 200 to 300 nm. We conclude that leaf starch is synthesized without appreciable turnover and comprises similar polymers and contains similar levels of molecular organization to storage starches, making Arabidopsis an excellent model system for studying granule biosynthesis.The Arabidopsis leaf is an excellent system in which to study starch granule biosynthesis for several reasons. First, starch accumulates in large amounts over a short period; up to one-half of the carbon assimilated through photosynthesis is stored as starch during the light period. As a consequence, it is possible to analyze the composition and structure of starch made over a period of a few hours by a defined set of enzymes. In contrast, starch synthesis in storage organs occurs over a long developmental period, during which there are usually considerable changes in the complement of starch-synthesizing enzymes (Smith and Martin, 1993; Burton et al., 1995) and in overall cellular conditions. Second, the rate of starch synthesis in leaves can be controlled by altering the irradiance and measured accurately by supplying 14 CO 2 . Third, our knowledge of the complete genome sequence of Arabidopsis and the availability of transposon and T-DNA-tagged populations enables specific knockout mutation...

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“…First, changes in the concentration of ADP-Glc can affect the relative activities of isoforms of starch synthase, and hence starch structure (Van den Koornhuyse et al, 1996;Clarke et al, 1999). GBSS has a much lower affinity for ADPGlc than soluble isoforms, and there appear to be differences between the soluble isoforms in their affinities for this substrate (Clarke et al, 1999;Edwards et al, 1999a;Lloyd et al, 1999a).…”

Section: Plants With Alterations In the Pattern Of Suc Supply To The mentioning

confidence: 99%

Growth Ring Formation in the Starch Granules of Potato Tubers

Pilling

Smith

2003

Plant Physiology

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Starch granules from higher plants contain alternating zones of semicrystalline and amorphous material known as growth rings. The regulation of growth ring formation is not understood. We provide several independent lines of evidence that growth ring formation in the starch granules of potato (Solanum tuberosum) tubers is not under diurnal control. Ring formation is not abolished by growth in constant conditions, and ring periodicity and appearance are relatively unaffected by a change from a 24-h to a 40-h photoperiod, and by alterations in substrate supply to the tuber that are known to affect the diurnal pattern of tuber starch synthesis. Some, but not all, of the features of ring formation are consistent with the involvement of a circadian rhythm. Such a rhythm might operate by changing the relative activities of starch-synthesizing enzymes: Growth ring formation is disrupted in tubers with reduced activity of a major isoform of starch synthase. We suggest that physical as well as biological mechanisms may contribute to the control of ring formation, and that a complex interplay of several factors may by involved.Starch granules from every higher plant species studied so far contain alternating regions of semicrystalline and amorphous material commonly known as growth rings. Growth rings can be observed by light microscopy, by atomic force microscopy, and by scanning and transmission electron microscopy (SEM and TEM) after treatment of granules with acid or degradative enzymes. These methods reveal that the rings represent alternating concentric layers of high/low refractive index, density, crystallinity, and resistance to chemical and enzymatic attack (Badenhuizen, 1939; Badenhuizen, 1959; Buttrose, 1960;Gallant and Guilbot, 1969;Hall and Sayre, 1973; Baker et al., 2001).The origin of growth rings remains obscure. Previous studies have suggested that one of two biological mechanisms could regulate their formation. First, their formation could be under the control of a diurnal rhythm that is dependent on day/night variations in the environment, such as a light/dark regime or alternating temperature cycles. Meyer (1895) hypothesized that growth of the granule follows a diurnal rhythm and that one growth ring is laid down per day. Support for this comes from studies of growth rings in the starch of developing cereal endosperm. Granules from barley (Hordeum vulgare) endosperm were claimed to have one growth ring for each day after their initiation (Buttrose, 1960), and growth rings were not visible in granules from the endosperm of wheat (Triticum aestivum) and barley plants grown in constant light and temperature (Van de Sande-Bakhuyzen, 1925; Buttrose, 1960 Buttrose, , 1962. Rings reappeared in the peripheral regions of granules when plants grown initially in constant conditions were transferred to a day-night regime during the course of granule development (Buttrose, 1962). These observations lead Buttrose (1962) to propose that growth ring formation is controlled by a diurnal rhythm that is dependent on ...

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Control of Starch Composition and Structure through Substrate Supply in the Monocellular Alga

Cited by 93 publications

References 34 publications

Characterization of ADG1, an Arabidopsis locus encoding for ADPG pyrophosphorylase small subunit, demonstrates that the presence of the small subunit is required for large subunit stability

Characterization of ADG1, an Arabidopsis locus encoding for ADPG pyrophosphorylase small subunit, demonstrates that the presence of the small subunit is required for large subunit stability

Starch Synthesis in Arabidopsis. Granule Synthesis, Composition, and Structure

Growth Ring Formation in the Starch Granules of Potato Tubers

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