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Glucose-1-phosphate transport into protoplasts and chloroplasts from leaves of Arabidopsis
- Source :
- Plant physiology. 155(4)
- Publication Year :
- 2010
-
Abstract
- Almost all glucosyl transfer reactions rely on glucose-1-phosphate (Glc-1-P) that either immediately acts as glucosyl donor or as substrate for the synthesis of the more widely used Glc dinucleotides, ADPglucose or UDPglucose. In this communication, we have analyzed two Glc-1-P-related processes: the carbon flux from externally supplied Glc-1-P to starch by either mesophyll protoplasts or intact chloroplasts from Arabidopsis (Arabidopsis thaliana). When intact protoplasts or chloroplasts are incubated with [U-14C]Glc-1-P, starch is rapidly labeled. Incorporation into starch is unaffected by the addition of unlabeled Glc-6-P or Glc, indicating a selective flux from Glc-1-P to starch. However, illuminated protoplasts incorporate less 14C into starch when unlabeled bicarbonate is supplied in addition to the 14C-labeled Glc-1-P. Mesophyll protoplasts incubated with [U-14C]Glc-1-P incorporate 14C into the plastidial pool of adenosine diphosphoglucose. Protoplasts prepared from leaves of mutants of Arabidopsis that lack either the plastidial phosphorylase or the phosphoglucomutase isozyme incorporate 14C derived from external Glc-1-P into starch, but incorporation into starch is insignificant when protoplasts from a mutant possessing a highly reduced ADPglucose pyrophosphorylase activity are studied. Thus, the path of assimilatory starch biosynthesis initiated by extraplastidial Glc-1-P leads to the plastidial pool of adenosine diphosphoglucose, and at this intermediate it is fused with the Calvin cycle-driven route. Mutants lacking the plastidial phosphoglucomutase contain a small yet significant amount of transitory starch.
- Subjects :
- Chloroplasts
Physiology
Starch
Glucose 1-phosphate
Arabidopsis
Plant Science
macromolecular substances
Glucose-1-Phosphate Adenylyltransferase
Biology
chemistry.chemical_compound
Glycogen phosphorylase
Genetics
Arabidopsis thaliana
Institut für Biochemie und Biologie
Research Articles
Carbon Isotopes
Arabidopsis Proteins
Protoplasts
fungi
Glucosephosphates
food and beverages
Biological Transport
Protoplast
biology.organism_classification
Chloroplast
carbohydrates (lipids)
Plant Leaves
chemistry
Biochemistry
Glucosyltransferases
Mutation
Phosphoglucomutase
lipids (amino acids, peptides, and proteins)
Subjects
Details
- ISSN :
- 15322548
- Volume :
- 155
- Issue :
- 4
- Database :
- OpenAIRE
- Journal :
- Plant physiology
- Accession number :
- edsair.doi.dedup.....1f03c8efc89eeee47c5f9079227acc33