title: ALTERNATIVE AND CYCLIC ELECTRON TRANSPORT: REGULATION AND ROLE IN PLANT PHOTOSYNTHESIS
reg no: ETF6607
project type: Estonian Science Foundation research grant
subject: 1.5. Biophysics
1.9. Genetics, Physiology and Microbiology
status: accepted
institution: TU Faculty of Biology and Geography
head of project: Agu Laisk
duration: 01.01.2006 - 31.12.2009
description: Correct stoichiometry of the supply of the assimilatory power (ATP) and reducing power (NADPH) is the primary prerequisite for efficient photosynthesis in plants. Recent advances in the structure of the chloroplast ATP synthase suggest the necessary stoichiometry is not guaranteed by linear electron/proton transport from water to CO2. Consequently, additional ATP synthesis must be supported, either by cyclic electron flow around PSI or alternative electron flow to acceptors other than CO2. During our previous grant ETF 5236 we have worked out methods for the measurement of the cyclic and alternative electron flow in leaves. Preliminary experiments suggested cyclic flow exists, but is uncoupled from the proton transport and cannot support ATP synthesis. Alternative electron transport, especially its malate dehydrogenase-supported component seems to play the major role in photosynthesis. In this project we shall investigate the rate and control of the malate dehudrogenase-related alternative electron transport, its relation to CO2 fixation by RuBP carboxylase and adjustment to environmental conditions. Gene silencing techniques will be introduced in the laboratory and the malate dehydrogenase gene will be silenced in Nicotiana benthamianis, with an aim to check the importance of this enzyme in leaf photosynthesis. The roles of the alternative and cyclic electron flow in photosynthesis will be compared.

project group
no name institution position  
1.Irina Bichele 
2.Hillar Eichelmann 
3.Agu LaiskTartu Ülikool 
4.Vello Oja 
5.Evi Padu 
6.Hugo Pettai 
7.Bahtijor Rasulov 
8.Eero Talts