Plastid translation and plant development
(Read more at Max-Planck-Institut Potsdam-Golm)
Ralph Bock | Max-Planck-Institut Potsdam-Golm
Early genetic work and recent transplastomic experiments have established that the genotype of the plastid influences morphological traits of the plant (such as leaf shape) and that the fidelity of plastid translation is crucial to plant growth and development. Why plant development is dependent on plastid translation, which nuclear genes are targeted by signals originating from plastid protein biosynthesis and which gene(s) on the plastid genome are involved in determining these so-called ‘extraplastidic traits’ is not known. Also, the signals and signaling pathways emanating from the plastid and mediating the extraplastidic responses to plastid translational activity are currently not understood. In general, two models seem plausible:
- The continuous production of plastid proteins is sensed and the information transmitted into the nucleus (e.g. by transient interaction of a translation product with a sensor protein in the plastid envelope).
- Alternatively, a plastid-encoded protein could be directly or indirectly involved in the production of a signaling metabolite that is either membrane-diffusible or actively exported from the plastid
Aims of project 6
Our project aims to define the role of plastid translation for the regulation of nuclear genes and the expression of morphological characters in plants and to identify components of the underlying signaling pathway(s). To this end, the phenotypic consequences of down-regulated plastid translation for leaf and flower development are assessed by a combination of genetic approaches (employing chloroplast transformation technology) and pharmacological approaches with transcript and metabolite profiling techniques. We have devised experimental systems suitable to
- Identify the sets of nuclear genes and metabolic pathways that depend on retrograde signals from plastid translation in Arabidopsis and tobacco,
- Precisely define the role of plastid translation for the expression of morphological traits and
- Identify signaling components (promoter elements, proteins, metabolic signals) in this intracellular communication pathway