Reduction of the cytosolic phosphoglucomutase in Arabidopsis reveals impact on plant growth, seed and root development, and carbohydrate partitioning.
Phosphoglucomutase (PGM) catalyses the interconversion of glucose 1-phosphate (G1P) and glucose 6-phosphate (G6P) and exists as plastidial (pPGM) and cytosolic (cPGM) isoforms. The plastidial isoform is essential for transitory starch synthesis in chloroplasts of leaves, whereas the cytosolic counterpart is essential for glucose phosphate partitioning and, therefore, for syntheses of sucrose and cell wall components. In Arabidopsis two cytosolic isoforms (PGM2 and PGM3) exist. Both PGM2 and PGM3 are redundant in function as single mutants reveal only small or no alterations compared to wild type with respect to plant primary metabolism. So far, there are no reports of Arabidopsis plants lacking the entire cPGM or total PGM activity, respectively. Therefore, amiRNA transgenic plants were generated and used for analyses of various parameters such as growth, development, and starch metabolism. The lack of the entire cPGM activity resulted in a strongly reduced growth revealed by decreased rosette fresh weight, shorter roots, and reduced seed production compared to wild type. By contrast content of starch, sucrose, maltose and cell wall components were significantly increased. The lack of both cPGM and pPGM activities in Arabidopsis resulted in dwarf growth, prematurely die off, and inability to develop a functional inflorescence. The combined results are discussed in comparison to potato, the only described mutant with lack of total PGM activity.
Plant Physiology, University of Potsdam, Potsdam-Golm, Germany; Biopolymers analytics, University of Potsdam, Potsdam-Golm, Germany.
Irina
I
Malinova
Plant Physiology, Washington State University, Pullman, Washington, United States of America; Department of Botany II, University of Cologne, Cologne, Germany.
Hans-Henning
HH
Kunz
Max-Planck-Institute of Molecular Plant Physiology, Potsdam-Golm, Germany.
Saleh
S
Alseekh
Plant Physiology, University of Potsdam, Potsdam-Golm, Germany.
Karoline
K
Herbst
Max-Planck-Institute of Molecular Plant Physiology, Potsdam-Golm, Germany.
Alisdair R
AR
Fernie
Department of Botany II, University of Cologne, Cologne, Germany.
Markus
M
Gierth
Plant Physiology, University of Potsdam, Potsdam-Golm, Germany; Biopolymers analytics, University of Potsdam, Potsdam-Golm, Germany.
Joerg
J
Fettke
D017360:Arabidopsis / Q000502:physiology*; D050260:Carbohydrate Metabolism; D003600:Cytosol / Q000378:metabolism*; D004789:Enzyme Activation; D007527:Isoenzymes; D055442:Metabolome; D055432:Metabolomics; D010641:Phenotype; D010733:Phosphoglucomutase / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism*; D030821:Plants, Genetically Modified; D012639:Seeds / Q000378:metabolism*; D013213:Starch / Q000378:metabolism
D007527:Isoenzymes; D013213:Starch; D010733:Phosphoglucomutase