Function of chloroplast nucleoids in C4 photosynthetic differentiation.

In C4-plants, the separation of photosynthetic functions between highly specialized mesophyll (M) and bundle sheath (BS) chloroplasts allows an efficient CO₂ fixation. Gene networks at the origin of the C4-syndrome remain largely undiscovered particularly at the level of plastid gene expression (PGE). Considering the high differentiation of the photosynthetic apparatus in M and BS chloroplasts, we hypothesize that regulatory factors responsible of C4-specific PGE will act at the level of the nucleoids (plastid protein-DNA-RNA complexes) that regroup proteins implicated in all levels of PGE. The ANR project TOCCATA is coordinated by Wojciech Majeran (Institut des Sciences des Plantes - Paris-Saclay - IPS2, CNRS/INRAE/U-Paris/UPSaclay/UEVE, Gif-sur-Yvette, Organellar Gene Expression), in collaboration with Marie-Laure Martin-Magniette and Guillem Rigail (Genomics Networks (Gnet), IPS2), as well as with Klaas Jan van Wijk (van Wijk Lab. Cornell University, Ithaca, NY, USA). This project aims at revealing C4-specific regulations in a comparative and never undertaken approach combining proteomics and transcriptomics of M and BS nucleoids. This parallel aims to reveal proteins and post-transcriptional mRNA maturation events implicated in C4-diferentiation. Functions and mechanisms of action of candidate proteins will be explored through a reverse genetic analysis.

Octobre 18, 2021