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Dissertation Information for Stacy Lynn DeBlasio

NAME:
- Stacy Lynn DeBlasio

DEGREE:
- Ph.D.

DISCIPLINE:
- Biology

SCHOOL:
- Indiana University (USA) (2005)

ADVISORS:
- Roger Hangarter

COMMITTEE MEMBERS:
- Roger Innes
- David Kehoe
- William Saxton

MPACT Status: Incomplete - Not_Inspected

Title: Characterization of blue-light induced chloroplast movements in wild-type and pmi (plastid movement impaired) Arabidopsis mutants

Abstract: Photosynthesis is a critical process required for normal plant development. Consequently, plants have evolved responses to maximize light absorption under varying environmental conditions. One such response is light-dependent chloroplast movement. In flowering plants like Arabidopsis thaliana , blue light induces chloroplast movement along the actin cytoskeleton. The intensity of the light determines which direction the chloroplasts move. Chloroplasts exposed to low intensities of light migrate perpendicular to the direction of the light, presumably to optimize absorption by exposing more surface area to the light. Exposure to high light causes chloroplasts to migrate parallel to the light. This response protects the chloroplasts by reducing their exposure to light intensities that are damaging to the proteins involved in photosynthesis. Blue-light-dependant chloroplast movements are mediated by the blue light photoreceptors phototropin1 and phototropin2. The overall goal of my thesis project was to identify and characterize components of the Arabidopsis chloroplast movement pathway so a more complete molecular model of the process could be formed. Photometric analysis of the chloroplast movement responses of various Arabidopsis photoreceptor mutants has revealed new insights into how the phototropins and phytochromes modulate BL-induced chloroplast movements. In addition, Arabidopsis mutants with altered chloroplast movements were isolated through a screening procedure based on using changes in light transmittance through leaves as a reliable indicator of chloroplast relocation. We have designated these mutants pmi for p lastid m ovement i mpaired. I have focused on cloning pmi1 , a mutant that exhibits severely attenuated chloroplast movements under all light conditions tested. Using various molecular techniques such as PCR based mapping and Agrobacterium mediated transformation, I was able to determine that pmi1 plants contain a single point mutation within a gene that encodes a plant-specific protein that is highly conserved among angiosperms. Sequence analysis of the protein suggests that it may be involved in calcium-mediated signal transduction, most likely through protein-protein interactions.

MPACT Scores for Stacy Lynn DeBlasio

A = 0
C = 0
A+C = 0
T = 0
G = 0
W = 0
TD = 0
TA = 0
calculated 2010-09-29 15:07:51

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