Post-transcriptional Control of Chloroplast Gene Expression

Margaret J. Hollingsworth, Ph.D.

Ph.D.: University of Colorado, Boulder

Postdoctoral Work: University of Texas Southwestern Medical Center at Dallas

The long-term goal of the research in my lab is to improve plant function and sustainability, particularly in the face of a changing environment.

We approach this goal from both whole-plant and molecular biology perspectives.

Whole-plant research to determine whether Spiroplasma infection protects crop plants from parasitic nematodes

Plant-parasitic nematodes cause significant crop losses worldwide. Colleagues in the Jaenike lab (University of Rochester) have discovered that a fly species parasitized by a nematode similar to those that destroy plants is protected from the nematodes by a symbiotic bacteria from the genus Spiroplasma (Jaenike et al. 2010). Experiments are in progress to determine whether crop plants can tolerate infection with the particular Spiroplasma species that has been shown to confer nematode resistance in flies. If we find plants in which these bacteria can grow without adversely affecting the plant's function, further experiments are planned to discover whether the Spiroplasma render their plant hosts resistant to plant parasitic nematodes, similar to their effect in flies.

Molecular-level research into post-transcriptional control of chloroplast gene expression

Chloroplast translation is essential for plant survival. Despite this, the factors involved in land plant chloroplast translation are neither well-defined nor well-understood. The goal of these experiments is to better understand the fundamentals of chloroplast translation in land plants.

Land plant chloroplast translation is primarily controlled by the interaction of nuclear-encoded proteins with 5' untranslated regions (5' UTRs) of chloroplast mRNAs. We have discovered that some chloroplast 5' UTR-binding proteins recognize a diverse assortment of chloroplast mRNAs (Robida et al 2002). We have also begun to define phylogenetically conserved elements in chloroplast 5' UTRs that are absolutely required for efficient translation in vivo (Baecker et al 2009). We hypothesize that interactions between these 5' UTR elements and their binding proteins may be responsible for global regulation of chloroplast translation.

J. Jaenike, R. Unckless, S. N. Cockburn, L. M. Boelio, S. J. Perlman (2010) "Adaptation via symbiosis: recent spread of a Drosophila defensive symbiont" Science 329 212-215