Poster: Tropisms

Abs # 414: Transcription profiling of the gps mutants

Presenter:	Hildenbrand, C. Dustin , cash_pudding@hotmail.com
Authors	Hildenbrand, C. Dustin  (A)   Nadella, Vijayanand  (A)   Wyatt, Sarah E (A)
Affiliations:	(A): Ohio University

Gravity is a fundamental stimulus governing plant growth and development. Normally, plant shoots bend up in response to gravistimulation. However, if plants are put on their side at 4^oC, this response is not seen. If returned to room temperature in the upright position, they bend in response to the gravitropic stimulus received in the cold (the gravity persistent signal, or gps response). Utilizing this phenomenon, 3 mutants were isolated that were defective in the early events of signal transduction: the inflorescence stems of gps1 show no gps response, those of gps2 respond, but with the gravity vector, and those of gps3 respond in the correct direction but "overshoot" the predicted position. In order to identify additional components of the gravitropic signal transduction pathway, transcription profiling of the gps mutants was implemented. WT and gps mutants were grown to maturity. Once the inflorescence stems reached ca. 10cm, the plants were gravistimulated at 4^oC for 2h. Plants were then returned to vertical at room temperature, and the inflorescence stem treated with RNAlater (Qiagen) after 5 min to stabilize RNA. Total RNA was then extracted from the elongation zone of the stem and sent to DNA Microarray Facility at University of California, Irvine for labeling and hybridization of the targets to the Affymetrix Genome ATH1 arrays. To control for the effects of the cold temperature alone, additional gps and WT plants were kept vertical at 4^oC for the 2 h period and treated as above. Further analysis of the data obtained will be useful in elucidating the early events of the gravitropic signal transduction pathway. (Supported by ASPB Summer Undergraduate Research Fellowship and an Ohio University Provost Undergraduate Research Fund Award to CDH.)