Abstract

In all multicellular eukaryotes mechanisms have evolved to regulate gene expression in specific cell types. In plants, this is clearly exemplified by the compartmentation of photosynthesis gene expression between the mesophyll (M) and bundle sheath (BS) cells of C4 species. Good progress has been made towards understanding elements that generate BS specificity in the C4 leaf, but this is not the case for ancestral C3 species that also contain BS cells. I aim to provide insight into how gene expression is restricted to BS cells in C3 plants, and then determine whether these mechanisms have been directly recruited into regulating BS specificity in the C4 system. I will initially focus on three Sulphate transporters and three MYB transcription factors whose transcripts have recently been shown to accumulate preferentially on the ribosomes of BS cells. Once I have defined specific regions that are sufficient to generate gene expression in the BS of A. thaliana, I will investigate if these BS regulators have been recruited by C4 plants to regulate the C4 cycle.