Development rooted in interwoven networks

Philip Benfey, Duke University – Dept of Biology
Determining the identity of different cells is central to the development of both plants and animals. In an effort to understand the networks that control cell identity, we have analyzed the gene expression in all cell types as well as in multiple developmental stages within the Arabidopsis root. To acquire global expression profiles we developed technology that uses sorted marked populations of cells with subsequent hybridization of the labeled RNA to genome-wide expression microarrays. We are using experimental methods to identify networks functioning within different cell types and developmental stages under normal laboratory conditions and under different environmental stress conditions. A key aspect of a plant’s ability to explore its below-ground environment is the production of branch or lateral roots. Lateral roots form as repeating units along the root, however the developmental mechanism regulating this process is unknown. We found that cyclic expression pulses of a reporter gene mark the position of future lateral roots by establishing prebranch sites and that prebranch site production is periodic. Further analysis revealed two sets of genes oscillating in opposite phases at the root tip. Genetic studies show that some oscillating transcriptional regulators are required for periodicity in lateral root formation. Finally, we are analyzing the dynamics of growth of physical root networks using novel non-invasive imaging methods and developing mathematical descriptors of root system architecture.
April, 25 2011 | - | Duke University – 329 Soc/Psych

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