Abstract
Screening of transposon-associated mutants of Arabidopsis thaliana for altered starch metabolism resulted in the isolation of a mutant that did not accumulate starch in any tissue or at any developmental stage (starch-free mutant, stf1). Allelism tests with known mutants showed that stf1 represents a new mutant allele of the plastid isoform of the enzyme phosphoglucomutase (PGMp). The mutation was mapped to chromosome 5. An Arabidopsis EST that showed significant homology to the cytosolic isoform of phosphoglucomutase (PGM) from maize was able to complement the mutant phenotype. The Arabidopsis EST was transcribed and translated in vitro and the protein product was efficiently imported into isolated chloroplasts and processed to its mature form. The lack of starch biosynthesis in stf1 is accompanied by the accumulation of soluble sugars. The rate of CO2 assimilation measured in individual leaves was substantially diminished only under conditions of high CO2 and low O2. Remarkably, stf1 exhibits an increase rather than a decrease in total leaf PGM activity, suggesting an induction of the cytosolic isoform(s) in the mutant. The substrate for PGM, glucose 6-phosphate, accumulated in stf1 during the day, resulting in 10-fold higher content than in the wild type at the end of the photoperiod.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
Author information
Authors and Affiliations
Additional information
Received: 4 January 2000 / Accepted: 21 March 2000
Rights and permissions
About this article
Cite this article
Kofler, H., Häusler, R., Schulz, B. et al. Molecular characterisation of a new mutant allele of the plastid phosphoglucomutase in Arabidopsis, and complementation of the mutant with the wild-type cDNA. Mol Gen Genet 263, 978–986 (2000). https://doi.org/10.1007/PL00008698
Issue Date:
DOI: https://doi.org/10.1007/PL00008698