The biosynthesis of isoprenoids in plants is an important pathway involved in the production of various light absorbing products such as chlorophyll. Although much is known about chlorophyll, questions remain concerning how plants prioritize the partitioning of chlorophyll and carotenoid precursor molecules and how chloroplast development and synthesis is tied to leaf development. Within the plastidial MEP pathway, geranylgeranyl diphosphate synthase 11 (GGPPS) is a major producer of the branchpoint compound GGPP. A point mutation in ggpps11-1 in Arabidopsis thaliana causes a variegated leaf phenotype and altered leaf morphology. We hypothesize that this temperature-dependent variegation is caused by a temperature gradient within the shoot apical meristem that leads to differential activity of GGPPS11 in meristem layers. To test this, we have constructed plasmids to express wild-type GGPPS11 within individual meristem areas using the promoters WUS and AtML1. In addition, leaf morphology and albino sector size were measured under a variety of temperature and light treatments. Temperature significantly impacted leaf and chlorophyll development in the ggpps11-1 mutant. While changing light environments did seem to play a role in controlling the variegation patterns, this was likely a side-effect of temperature changes induced by increased light intensity. It was determined that temperature has a greater influence on leaf development, morphology, variegation patterns and chlorophyll levels in ggpps11-1 compared to irradiance.
|Commitee:||Williams, Jason, Liebl, Faith|
|School:||Southern Illinois University at Edwardsville|
|School Location:||United States -- Illinois|
|Source:||MAI 81/2(E), Masters Abstracts International|
|Subjects:||Plant sciences, Molecular biology, Cellular biology|
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