Post-doctoral Researcher
Dr. Dereth R. Phillips
A touchy screen...
The gene TCH4 (XTH22), encoding a xyloglucan endotransglycosylase/hydrolase, exhibits an increase transcription rate in response to touch. In order to produce this effect, there must exist a series of molecular intermediaries that transform the mechanical stimulation of the plant into an increase in TCH4 expression. We are currently using a genetic approach to search for these missing molecules.
Expression screen
We monitor TCH4 expression in an Arabidopsis line in which the regulatory region of TCH4 is linked to the gene for firefly luciferase. In the presence of the compound luciferin, these plants glow in response to touch stimuli. We screened pools of EMS-generated mutants of this TCH4::LUC line for those plants exhibiting aberrant levels of luciferase expression. Approximately 40 lines were found to glow to a reproducibly greater extent than the parental TCH4::LUC plants and are currently being subjected to northern blot analysis to monitor their endogenous TCH4 expression.Phenotype screen
Touched plants often appear dwarfed when compared with untouched plants of the same genetic line. Among the mutagenized TCH4::LUC lines discussed above, we have also been collecting plants that remain full-sized in spite of being regularly touched. These plants appear able to circumvent the developmental program usually taken in response to touch. Thanks to their TCH4::LUC marker, we are able to determine if TCH4 regulation in these plants is altered as well.
Goal
Our goal is to elucidate the pathway by which TCH4 transcription rate is increased in response to touch and to determine its relationship to the pathway that governs the developmental response to touch stimuli.
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