title: The Starch Granule-Associated Protein EARLY STARVATION1 Is Required for the Control of Starch Degradation in Arabidopsis thaliana Leaves.
abstract: To uncover components of the mechanism that adjusts the rate of leaf starch degradation to the length of the night, we devised a screen for mutant Arabidopsis thaliana plants in which starch reserves are prematurely exhausted. The mutation in one such mutant, named early starvation1 (esv1), eliminates a previously uncharacterized protein. Starch in mutant leaves is degraded rapidly and in a nonlinear fashion, so that reserves are exhausted 2 h prior to dawn. The ESV1 protein and a similar uncharacterized Arabidopsis protein (named Like ESV1 [LESV]) are located in the chloroplast stroma and are also bound into starch granules. The region of highest similarity between the two proteins contains a series of near-repeated motifs rich in tryptophan. Both proteins are conserved throughout starch-synthesizing organisms, from angiosperms and monocots to green algae. Analysis of transgenic plants lacking or overexpressing ESV1 or LESV, and of double mutants lacking ESV1 and another protein necessary for starch degradation, leads us to propose that these proteins function in the organization of the starch granule matrix. We argue that their misexpression affects starch degradation indirectly, by altering matrix organization and, thus, accessibility of starch polymers to starch-degrading enzymes.
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom.
authors.forename: Doreen
authors.initials: D
authors.lastname: Feike
authors.affiliation: Department of Biology, Eidgenössische Technische Hochschule Zürich, CH-8092 Zürich, Switzerland.
authors.forename: David
authors.initials: D
authors.lastname: Seung
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom.
authors.forename: Alexander
authors.initials: A
authors.lastname: Graf
authors.affiliation: Department of Biology, Eidgenössische Technische Hochschule Zürich, CH-8092 Zürich, Switzerland.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Bischof
authors.affiliation: Department of Biology, Eidgenössische Technische Hochschule Zürich, CH-8092 Zürich, Switzerland.
authors.forename: Tamaryn
authors.initials: T
authors.lastname: Ellick
authors.affiliation: Department of Biology, Eidgenössische Technische Hochschule Zürich, CH-8092 Zürich, Switzerland.
authors.forename: Mario
authors.initials: M
authors.lastname: Coiro
authors.affiliation: Department of Biology, Eidgenössische Technische Hochschule Zürich, CH-8092 Zürich, Switzerland.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Soyk
authors.affiliation: Department of Biology, Eidgenössische Technische Hochschule Zürich, CH-8092 Zürich, Switzerland.
authors.forename: Simona
authors.initials: S
authors.lastname: Eicke
authors.affiliation: Department of Biology, Eidgenössische Technische Hochschule Zürich, CH-8092 Zürich, Switzerland.
authors.forename: Tabea
authors.initials: T
authors.lastname: Mettler-Altmann
authors.affiliation: Department of Biology, Eidgenössische Technische Hochschule Zürich, CH-8092 Zürich, Switzerland.
authors.forename: Kuan Jen
authors.initials: KJ
authors.lastname: Lu
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom.
authors.forename: Martin
authors.initials: M
authors.lastname: Trick
authors.affiliation: Department of Biology, Eidgenössische Technische Hochschule Zürich, CH-8092 Zürich, Switzerland.
authors.forename: Samuel C
authors.initials: SC
authors.lastname: Zeeman
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom alison.smith@jic.ac.uk.
authors.forename: Alison M
authors.identifier: 0000-0001-6927-9650
authors.initials: AM
authors.lastname: Smith
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D013213:Starch / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D013213:Starch