Poster: Global Change
Abs #
71: Unraveling the connection between starch granule metabolism and acetyl-CoA utilization
|
|
Presenter: |
Foster, Carol M., cmfoster@iastate.edu | Authors | Foster, Carol M. (A) Li, Ling (A) James, Martha G. (B) Myers, Alan M. (B) Wurtele, Eve S. (A) | | Affiliations: |
(A): Department of Botany, Iowa State University
(B): Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University
| |
|
Starch granules accumulate and degrade in leaf chloroplasts during the light and dark phases, respectively, indicating formation of granules is highly regulated throughout the diurnal cycle. Carbohydrate stored in starch granules contributes to many important physiological processes, such as seed germination and seedling growth. However, there is little understanding of the mechanisms involved in starch granule production. Another central metabolite, acetyl-CoA, is also required for many biochemical pathways critical to plant growth and development. ATP citrate lyase (ACL) produces acetyl-CoA from citrate in the cytosol. Transgenic Arabidopsis with decreased levels of ACL activity contain abnormally enlarged starch granules in leaves. To elucidate underlying molecular events involved in utilization of acetyl-CoA during starch metabolism, we used microarray technology to study global gene expression in wild-type and antisense-ACLA1 plants. Leaves were harvested from six-week-old seedlings grown under short day conditions. Total RNA was used to produce labeled cRNAs for hybridization with Affymetrix GeneChips. Data were analyzed using Bioconductor, GeneGobi, and Genespring software packages. Transcript accumulation for genes involved in starch assembly and disassembly oscillated as expected during the diurnal cycle. Differential expression of starch synthases, branching enzymes, debranching enzymes, amylases, disproportionating enzymes, and starch phosphorylases will be discussed. Northern blot analyses and real-time PCR are being used to confirm accumulation patterns of specific transcripts and to support conclusions drawn from our genechip data.
|
|
