Genome-wide gene expression profiles in response to plastid division perturbations.

Plastids are vital organelles involved in important metabolic functions that directly affect plant growth and development. Plastids divide by binary fission involving the coordination of numerous protein components. A tight control of the plastid division process ensures that: there is a full plastid complement during and after cell division, specialized cell types have optimal plastid numbers; the division rate is modulated in response to stress, metabolic fluxes and developmental status. However, how this control is exerted by the host nucleus is unclear. Here, we report a genome-wide microarray analysis of three accumulation and replication of chloroplasts (arc) mutants that show a spectrum of altered plastid division characteristics. To ensure a comprehensive data set, we selected arc3, arc5 and arc11 because they harbour mutations in protein components of both the stromal and cytosolic division machinery, are of different evolutionary origin and display different phenotypic severities in terms of chloroplast number, size and volume. We show that a surprisingly low number of genes are affected by altered plastid division status, but that the affected genes encode proteins important for a variety of fundamental plant processes.