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A low-starch barley mutant, risø 16, lacking the cytosolic small subunit of ADP-glucose pyrophosphorylase, reveals the importance of the cytosolic isoform and the identity of the plastidial small subunit.
Plant Physiol. 2003 Feb; 131(2):684-96.PP

Abstract

To provide information on the roles of the different forms of ADP-glucose pyrophosphorylase (AGPase) in barley (Hordeum vulgare) endosperm and the nature of the genes encoding their subunits, a mutant of barley, Risø 16, lacking cytosolic AGPase activity in the endosperm was identified. The mutation specifically abolishes the small subunit of the cytosolic AGPase and is attributable to a large deletion within the coding region of a previously characterized small subunit gene that we have called Hv.AGP.S.1. The plastidial AGPase activity in the mutant is unaffected. This shows that the cytosolic and plastidial small subunits of AGPase are encoded by separate genes. We purified the plastidial AGPase protein and, using amino acid sequence information, we identified the novel small subunit gene that encodes this protein. Studies of the Risø 16 mutant revealed the following. First, the reduced starch content of the mutant showed that a cytosolic AGPase is required to achieve the normal rate of starch synthesis. Second, the mutant makes both A- and B-type starch granules, showing that the cytosolic AGPase is not necessary for the synthesis of these two granule types. Third, analysis of the phylogenetic relationships between the various small subunit proteins both within and between species, suggest that the cytosolic AGPase single small subunit gene probably evolved from a leaf single small subunit gene.

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Authors+Show Affiliations

Johnson PE
John Innes Centre, Norwich Research Park, Colney, Norfolk NR4 7UH, United Kingdom.
Patron NJ
No affiliation info available
Bottrill AR
No affiliation info available
Dinges JR
No affiliation info available
Fahy BF
No affiliation info available
Parker ML
No affiliation info available
Waite DN
No affiliation info available
Denyer K
No affiliation info available

MeSH

Adenosine Diphosphate GlucoseAmino Acid SequenceCytosolDNA, ComplementaryGlucose-1-Phosphate AdenylyltransferaseGlucosyltransferasesHordeumIsoenzymesMicroscopy, Electron, ScanningMolecular Sequence DataMutationNucleotidyltransferasesPhylogenyPlastidsSeedsSequence Analysis, DNASequence Homology, Amino AcidStarch

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

12586892

Citation

Johnson, Philip E., et al. "A Low-starch Barley Mutant, Risø 16, Lacking the Cytosolic Small Subunit of ADP-glucose Pyrophosphorylase, Reveals the Importance of the Cytosolic Isoform and the Identity of the Plastidial Small Subunit." Plant Physiology, vol. 131, no. 2, 2003, pp. 684-96.
Johnson PE, Patron NJ, Bottrill AR, et al. A low-starch barley mutant, risø 16, lacking the cytosolic small subunit of ADP-glucose pyrophosphorylase, reveals the importance of the cytosolic isoform and the identity of the plastidial small subunit. Plant Physiol. 2003;131(2):684-96.
Johnson, P. E., Patron, N. J., Bottrill, A. R., Dinges, J. R., Fahy, B. F., Parker, M. L., Waite, D. N., & Denyer, K. (2003). A low-starch barley mutant, risø 16, lacking the cytosolic small subunit of ADP-glucose pyrophosphorylase, reveals the importance of the cytosolic isoform and the identity of the plastidial small subunit. Plant Physiology, 131(2), 684-96.
Johnson PE, et al. A Low-starch Barley Mutant, Risø 16, Lacking the Cytosolic Small Subunit of ADP-glucose Pyrophosphorylase, Reveals the Importance of the Cytosolic Isoform and the Identity of the Plastidial Small Subunit. Plant Physiol. 2003;131(2):684-96. PubMed PMID: 12586892.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A low-starch barley mutant, risø 16, lacking the cytosolic small subunit of ADP-glucose pyrophosphorylase, reveals the importance of the cytosolic isoform and the identity of the plastidial small subunit. AU - Johnson,Philip E, AU - Patron,Nicola J, AU - Bottrill,Andrew R, AU - Dinges,Jason R, AU - Fahy,Brendan F, AU - Parker,Mary L, AU - Waite,Darren N, AU - Denyer,Kay, PY - 2003/2/15/pubmed PY - 2003/5/24/medline PY - 2003/2/15/entrez SP - 684 EP - 96 JF - Plant physiology JO - Plant Physiol VL - 131 IS - 2 N2 - To provide information on the roles of the different forms of ADP-glucose pyrophosphorylase (AGPase) in barley (Hordeum vulgare) endosperm and the nature of the genes encoding their subunits, a mutant of barley, Risø 16, lacking cytosolic AGPase activity in the endosperm was identified. The mutation specifically abolishes the small subunit of the cytosolic AGPase and is attributable to a large deletion within the coding region of a previously characterized small subunit gene that we have called Hv.AGP.S.1. The plastidial AGPase activity in the mutant is unaffected. This shows that the cytosolic and plastidial small subunits of AGPase are encoded by separate genes. We purified the plastidial AGPase protein and, using amino acid sequence information, we identified the novel small subunit gene that encodes this protein. Studies of the Risø 16 mutant revealed the following. First, the reduced starch content of the mutant showed that a cytosolic AGPase is required to achieve the normal rate of starch synthesis. Second, the mutant makes both A- and B-type starch granules, showing that the cytosolic AGPase is not necessary for the synthesis of these two granule types. Third, analysis of the phylogenetic relationships between the various small subunit proteins both within and between species, suggest that the cytosolic AGPase single small subunit gene probably evolved from a leaf single small subunit gene. SN - 0032-0889 UR - https://www.unboundmedicine.com/medline/citation/12586892/A_low_starch_barley_mutant_risø_16_lacking_the_cytosolic_small_subunit_of_ADP_glucose_pyrophosphorylase_reveals_the_importance_of_the_cytosolic_isoform_and_the_identity_of_the_plastidial_small_subunit_ DB - PRIME DP - Unbound Medicine ER -