Affiliation
LMU Faculty of Biology - Division of Plant Science
Contact
Division of Plant Science
Großhaderner Straße 2
D-82152 Planegg-Martinsried
Phone:
+49 (0)89 / 2180 - 74750
Email:
kunz@lmu.de
Website:
https://www.en.botanik.bio.lmu.de/research/kunz/index.html
Research Focus
Analysis of putative cyanobacterial thylakoid ion transport proteins for their role in photosynthesis
The light reactions of photosynthesis generate a proton motive force across the thylakoid membrane which is used to generate ATP for cellular metabolism. In plants, the composition and dynamics of the proton motive force are regulated partially by ion flux across the thylakoid mediated by multiple ion transport proteins. Loss-of-function mutants in plants have shown that these proteins are critical for maintaining photosynthesis in natural environments. Surprisingly, our lab has shown that the thylakoid ion transport proteins known from plants are absent in cyanobacteria, where the same proton motive force regulation is expected to be important.
Using a model laboratory cyanobacterium (Synechocystis sp. PCC 6803), the lab has identified proteins likely to be ion transport proteins but which have no previous cellular localization. Stable knockout and fluorescently tagged lines for these proteins have been generated. Using the fluorescently tagged mutants, the student will identify proteins located in the thylakoid membrane using confocal microscopy and cellular membrane fractionation followed by immunoblotting. The knockout mutants for transport proteins located in the thylakoid membrane will then be characterized for alterations in growth (OD and biomass), photosynthesis (photosystem I and photosystem II activities), and cellular element content.
The student will clone the cyanobacterial gene for expression in E. coli and biochemical characterization of the protein’s ion selectivity and regulation. This will be coupled with expression of the transporter in E. coli mutant lines which lack specific ion transport capacity to test for growth recovery.
The identified transport protein will also be cloned into Agrobacterium tumefaciens for transient expression in tobacco. Using chlorophyll fluorescence imaging, the influence of this foreign protein on plant photosynthesis will be determined.
Must have lab skills:
- Capacity to make laboratory stock solutions (e.g. buffers, agar plates, etc.)
- Capability to perform microbiological techniques in order to maintain sterile cultures
- Standard molecular biology techniques for gene cloning
- Protein analysis using gel electrophoresis and immunoblotting
It is not expected that the student has previous knowledge of photosynthesis measurements.
Possible project supervisor:
Dr. Geoffry Davis, Alexander von Humbolt Postdoctoral Fellow in the lab of Professor Hans-Henning Kunz