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HPLC Analysis of Polyamines in Arabidopsis Thaliana Lines Altered in the Expression of Polyamine Transport

Ariyaratne, Menaka M
http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1404039834

Abstract Details

2014, Master of Science (MS), Bowling Green State University, Biological Sciences.
Polyamines are low molecular weight aliphatic organic compounds with two or more amino groups that are present in all living organisms and are essential for cell viability. Polyamine homeostasis in cells is maintained by their biosynthesis and degradation. Transport might also play an important role in maintaining polyamine homeostasis in plants, but less is known about polyamine transporters at the cellular level. Previous research in our lab has identified and characterized Arabidopsis and rice polyamine preferential uptake transporters (PUTs) that function as high affinity spermidine and low affinity putrescine uptake transporters. Transgenic Arabidopsis plants overexpressing these polyamine transporters showed a delay in flowering, but once they flower they had many more shoots and flowers. We hypothesized that these phenotypic changes were due to accumulation of polyamines. This was tested by quantifying polyamines in three Arabidopsis constructs with changes in the expression of a heterologous gene. All the transgenic plants had elevated soluble and conjugated spermidine levels before the flowering stage. These titers remained high during flowering and seed stages. Results of this study suggest that the delay in flowering observed in the transgenic lines might be due to accumulation of polyamines, especially spermidine that might affect gene expression. Almost all free living eukaryotes synthesize putrescine from ornithine via the enzyme ornithine decarboxylase (ODC), but the ODC gene has been lost from Arabidopsis thaliana and much of the Brassicaceae. Hence, we hypothesized the coexistence of two enzymes, ADC2 and agmatinase in the plastids of Arabidopsis which provide a second biosynthesis pathway for putrescine in plant cells. A yeast system was used to perform a complementation assay to test the plastid model for putrescine biosynthesis. The yeast spe1 mutant that has a disruption in the spe1 gene encoding ODC did not grow in the absence of exogenous putrescine, but after transformation with plasmids containing ADC2 and ARGAH2 genes, the ability to grow on minimal medium lacking polyamines was restored. This result provides evidence for a second putrescine biosynthesis pathway for Arabidopsis and some of Brassicaceae. Existence of plastid-localized putrescine biosynthesis also necessitates the coordinated regulation of putrescine export from this organelle.
Paul Morris, Dr. (Advisor)
Vipaporn Phuntumart, Dr. (Committee Member)
Helen Michaels, Dr. (Committee Member)
57 p.
Biochemistry; Biology; Molecular Biology
Polyamines; HPLC; polyamine transport

Recommended Citations

Citations

  • Ariyaratne, M. M. (2014). HPLC Analysis of Polyamines in Arabidopsis Thaliana Lines Altered in the Expression of Polyamine Transport [Master's thesis, Bowling Green State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1404039834

    APA Style (7th edition)

  • Ariyaratne, Menaka. HPLC Analysis of Polyamines in Arabidopsis Thaliana Lines Altered in the Expression of Polyamine Transport. 2014. Bowling Green State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1404039834.

    MLA Style (8th edition)

  • Ariyaratne, Menaka. "HPLC Analysis of Polyamines in Arabidopsis Thaliana Lines Altered in the Expression of Polyamine Transport." Master's thesis, Bowling Green State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1404039834

    Chicago Manual of Style (17th edition)

bgsu1404039834
2,969
© 2014, some rights reserved.Creative Commons License HPLC Analysis of Polyamines in Arabidopsis Thaliana Lines Altered in the Expression of Polyamine Transport by Menaka M Ariyaratne is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by Bowling Green State University and OhioLINK.