Dr. Parisa Rahimzadeh Karvansara

One of the long-term goals of photosynthesis research is to understand how photosystem II (PSII) is assembled from its component parts, how it is repaired following damage, and how these processes are affected by the changing environment.

Current models suggest that PSII is assembled in a step-wise manner and requires the participation of accessory factors not found in the final active complex. However, a number of open questions exist. How many factors are crucial for the biogenesis of fully functional photosystems and their antennas and which is their molecular nature and function? What is the sequence in which the assembly factors act? How has PSII assembly evolved to be able to cope with harsh environments that plants experience on land? I use the cyanobacteria Synechocystis sp. PCC 6803, the model plant Arabidopsis thaliana (Arabidopsis), and the model green alga Chlamydomonas reinhardtii (Chlamydomonas) to obtain insights into the evolution of the function of specific assembly factors in PSII biogenesis. Experimentally, I probe PSII assembly using an integrated cell biology approach that involves isolation and characterization of assembly complexes, determination of the structures of PSII assembly, and specific accessory factors. By obtaining a deeper insight into PSII assembly, we aim to provide insight into how the stability of PSII can be improved as well as how the repair process can be accelerated. New findings in this field will be fundamental for strategies to (i) enhance plant photosynthesis in the field or (ii) stabilize PSII for synthetic biology approaches to harness electrons from water.