The molecular basis of quantitative genetic variation in central and secondary metabolism in Arabidopsis.
To find the genes controlling quantitative variation, we need model systems where functional information on physiology, development, and gene regulation can guide evolutionary inferences. We mapped quantitative trait loci (QTLs) influencing quantitative levels of enzyme activity in primary and secondary metabolism in Arabidopsis. All 10 enzymes showed highly significant quantitative genetic variation. Strong positive genetic correlations were found among activity levels of 5 glycolytic enzymes, PGI, PGM, GPD, FBP, and G6P, suggesting that enzymes with closely related metabolic functions are coregulated. Significant QTLs were found influencing activity of most enzymes. Some enzyme activity QTLs mapped very close to known enzyme-encoding loci (e.g., hexokinase, PGI, and PGM). A hexokinase QTL is attributable to cis-acting regulatory variation at the AtHXK1 locus or a closely linked regulatory locus, rather than polypeptide sequence differences. We also found a QTL on chromosome IV that may be a joint regulator of GPD, PGI, and G6P activity. In addition, a QTL affecting PGM activity maps within 700 kb of the PGM-encoding locus. This QTL is predicted to alter starch biosynthesis by 3.4%, corresponding with theoretical models, suggesting that QTLs reflect pleiotropic effects of mutant alleles.
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Related Subject Headings
- Restriction Mapping
- Quantitative Trait, Heritable
- Models, Genetic
- Genetic Variation
- Genetic Markers
- Genetic Linkage
- Gene Expression Regulation, Plant
- Gene Expression Regulation, Enzymologic
- Developmental Biology
- Computational Biology
Citation
Published In
DOI
EISSN
ISSN
Publication Date
Volume
Issue
Start / End Page
Related Subject Headings
- Restriction Mapping
- Quantitative Trait, Heritable
- Models, Genetic
- Genetic Variation
- Genetic Markers
- Genetic Linkage
- Gene Expression Regulation, Plant
- Gene Expression Regulation, Enzymologic
- Developmental Biology
- Computational Biology