Identification of plant ferredoxin protein partners

PI : Jérémy Couturier (UMR 1136 – Tree/Microorganism Interactions — IAM)

Collaboration :

C. Didierjean (Université de Lorraine, CRM2)
O. Keech (Umeå Plant Science Centre, Suède)
G. Wingsle (Umeå Plant Science Centre, Suède)
S. Lemaire et C. Marchand (Institu de Biologie Physico-Chimique, Paris)

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Context — Ferredoxins are iron-sulfur proteins located at a branch point of organellar metabolism. In chloroplasts, they distribute electrons to metabolic processes as carbon, sulfur and nitrogen assimilation. In mitochondria, ferredoxins participate to the maturation of iron-sulfur proteins and to coenzyme Q or steroid biosynthesis. Ferredoxins recognize their partners by forming electrostastic interactions. This property was exploited for fishing ferredoxin partners by affinity chromatography. However, these experiments have been performed at a time where proteomic facilities were not as developed as now. As ferredoxins are hubs for many aspects of plant physiology and development, understanding their functions is a pre-requisite before thinking to engineer plants with better agronomical yield or improved stress tolerance.

Objective —This project aims at identifying new protein partners of the most abundant chloroplastic ferredoxin and of the two mitochondrial ferredoxins for which such study has never been done.

Approach — This project proposes to combine the ferredoxin trapping approach with more sensitive proteomic technologies that will allow to identify protein partners present in minor amounts and that were not previously identified. The molecular determinants for the most interesting interactions will be further explored by using complementary in vivo and in vitro approaches such as binary yeast two hybrid, bimolecular fluorescence complementation, and/or co-immunoprecipitation coupled to conventional biochemical and biophysical approaches using recombinant proteins.

Expected results and impacts — In a context of climate change and its associated environmental perturbations, this project may provide fundamental knowledge about proteins which are at a metabolic crossroad of carbon, nitrogen and sulfur pathways that are fundamental for plant survey. Therefore we anticipate that in the long run, we may be able from those data to engineer plants better adapted to stress and with better productivity, a key to human nutrition in the future