Trang Le - AG Matsubara

The circadian clock regulates various physiological and developmental processes in plants to synchronize the timing of these events with favorable phases of environmental cycles. Transcription of ca. 30% of Arabidopsis genes, including those in photosynthesis, responses to light, key metabolic and hormone pathways, is controlled by the clock. Also, leaf growth and hypocotyl elongation are under the circadian control in Arabidopsis plants. While light is the major signal input to entrain the clock, plants are naturally subjected to irregular changes in light environment. Exposure to higher or lower light intensity can induce various acclimatory responses in plants, depending on the intensity, duration and frequency of fluctuation. Recently, it has been shown that Arabidopsis has limited ability to utilize additional light energy during short and strong increase in light intensity (“sunflecks”). Under such conditions, their leaves show pronounced upregulation of defense against photooxidative stress. Furthermore, leaf morphology and shoot architecture change during the acclimation. Taking advantage of the effects of fluctuating light specifically inducing photooxidative defense responses in Arabidopsis, we investigate whether the circadian clock plays a role in regulating or coordinating photosynthetic and growth acclimation to photooxidative stress. Acclimatory responses are currently being studied at multiple levels (transcriptome, metabolites, photosynthesis and growth) in growing leaves (structural and biochemical adjustment) and fully expanded leaves (mainly biochemical adjustment) of wildtype Columbia at different times of the day. In parallel, acclimation patterns are also being analyzed in clock mutants. Following the identification of genes and pathways responding to fluctuating light conditions, future experiments will assess the capacities of mutants and transgenic plants, having alterations in those genes and pathways, to acclimate to photooxidative stress induced by sunflecks. Finally, cross-tolerance between photooxidative stress and other abiotic (e.g. drought) or biotic stress will be examined by using bioinformatics tools as well as physiological phenotyping platforms.

Starting date: 01.09.2012 / PhD student

Thesis committee members: Shizue Matsubara, Peter Jahns, Eva Farré

Mini Academic CV:

  • 2009:
    • Master of Science in Plant Sciences, University of Bonn. Germany. Thesis: Physiological characterization of the chilling sensitive 1 (chs1) mutant of Arabidopsis thaliana.
  • 2007:
    • Bachelor of Science in Biotechnology. Can Tho University. Vietnam. Thesis: Collecting and propagating invitro vegetative shoots from dormant nodes of Phalaenopsis flower stalks.

Trang Le

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Responsible for the content: E-MailDr. Petra Fackendahl