Function of chloroplast nucleoids in C4 photosynthetic differentiation. – TOCCATA

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 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. Our proposal 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 reverse genetic analysis.