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The Role of PKS1 in Root Phototropism

Kuntz, Ashley L.
http://rave.ohiolink.edu/etdc/view?acc_num=muhonors1177531764

Abstract Details

2007, Bachelor of Science, Miami University, College of Arts and Sciences - Botany.
Acquiring information about the surrounding environment is crucial to the survival of all living organisms including plants. Therefore, an incredible diversity of sensory systems has evolved to recognize and relay incoming environmental stimuli such as light, touch, and gravity. Directed growth-based responses in plants to unilateral stimuli are called tropisms. Specifically, light is a major environmental factor that governs the growth and development of plants. To detect and respond to the varying fluence, wavelength, and direction of light, plants have evolved several types of photoreceptors. The phytochromes, in particular PHYA and PHYB in the flowering plant Arabidopsis thaliana, are two main receptors of red light that play important roles in regulating many of the light-induced responses. Photoperception of red light by these phytochromes triggers specific intracellular signaling pathways that induce selective changes in gene expression. Using microarray technology and quantitative Real-Time PCR (qRT-PCR), we found the gene PKS1 to be up-regulated five-fold in response to red light, providing strong evidence that the phototropic response was activated by red light in roots. In order to confirm conclusively that the gene PKS1 was involved in red light phototropism, experiments with the computer-based feedback imaging system ROTATO were performed. Our phototropic studies of roots using the feedback system ROTATO suggested an interaction between PKS1 and PHYA since the roots of the double mutant pks1phyA had negative curvature. The phyA mutant showed an even greater negative curvature. Furthermore, time course experiments using qRT-PCR found that there was a consistent two-fold increase in PKS1 expression to red light exposure. The phyA mutant showed only a 1.2-fold induction level of PKS1 expression with the use of qRT-PCR. Ultimately, we hypothesize that PKS1 mitigates the role that PHYA has in positive and negative root curvature in response to red light. PHYA was identified as the major component involved in regulating PKS1 gene expression in Arabidopsis.
John Kiss (Advisor)
phototropism; root phototropism; PKS1; red light

Recommended Citations

Citations

  • Kuntz, A. L. (2007). The Role of PKS1 in Root Phototropism [Undergraduate thesis, Miami University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=muhonors1177531764

    APA Style (7th edition)

  • Kuntz, Ashley. The Role of PKS1 in Root Phototropism. 2007. Miami University, Undergraduate thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=muhonors1177531764.

    MLA Style (8th edition)

  • Kuntz, Ashley. "The Role of PKS1 in Root Phototropism." Undergraduate thesis, Miami University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=muhonors1177531764

    Chicago Manual of Style (17th edition)

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© 2007, all rights reserved.
This open access ETD is published by Miami University Honors Theses and OhioLINK.