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Many maize inbreds lack an endosperm cytosolic phosphoglucomutase
D Pan1, L I Strelow, O E Nelson
1Laboratory of Genetics, University of Wisconsin, Madison, Wisconsin 53706.
Plant Physiology
|August 1, 1990
Summary
Most maize inbreds show one phosphoglucomutase zone due to lacking a cytosolic isozyme. This absence, however, has no observable effect on plant phenotypes.
Area of Science:
- Plant genetics
- Biochemistry
- Maize molecular biology
Background:
- Phosphoglucomutase (PGM) is a key enzyme in carbohydrate metabolism.
- Isozymes of PGM exist in different cellular compartments, including amyloplasts and cytosol.
- Genetic variation in PGM isozymes can occur within maize (Zea mays L.) inbred lines.
Purpose of the Study:
- To investigate the genetic basis of phosphoglucomutase (PGM) isozyme variation in developing maize endosperms.
- To characterize the cellular localization of different PGM activity zones.
- To determine if the absence of a specific PGM isozyme impacts maize phenotype.
Main Methods:
- Starch gel electrophoresis was used to analyze PGM activity in maize endosperm extracts.
- Enzyme extracts were prepared from developing maize (Zea mays L.) endosperms at 22 days postpollination.
- Comparison of PGM zymograms across different maize inbred lines.
Main Results:
- The majority of maize inbreds displayed a single zone of phosphoglucomutase (PGM) activity.
- This consistent activity corresponds to the amyloplast isozyme.
- A subset of inbreds exhibited two zones, including an absent cytosolic enzyme form.
- The absence of the cytosolic PGM isozyme did not result in discernible phenotypic differences.
Conclusions:
- A common genetic variant in maize (Zea mays L.) leads to the absence of the cytosolic phosphoglucomutase (PGM) isozyme.
- The amyloplast PGM isozyme is essential and present in all tested maize inbreds.
- The lack of cytosolic PGM activity does not appear to affect the overall phenotype of maize plants.