The gravity persistent signal (gps) mutants are the star of this show. Gravity is a fundamental stimulus governing plant growth and development. Normally, plant shoots bend up in response to being on their side (gravistimulation). However, if plants are put on their side in the cold, they don't bend. But if you return them to room temperature, they bend in response to the cold signal. They "remember". Plants can sense gravity in the cold but cannot respond. The hormone (auxin) that causes bending is not transported properly and, therefore, the plants don't bend. We used this phenomenon to find mutants that were defective in the mechanisms responsible for the signal transduction events linking perception of gravity and the transport of auxin.
Selected Papers :
Nadella, V., Hildenbrand, C.D., and S. E. Wyatt (2006) Transcription profiling of the gps1 mutant of Arabidopsis. Gravitational and Space Biology 20:155-156.
Nadella, V., Shipp, M. J., Muday, G.K, Wyatt, S.E. (2006) Evidence for altered polar and lateral auxin transport in the gravity persistent signal (gps) mutants of Arabidopsis. Plant Cell and Environment 29:682-690. (cover)(link)
Wyatt, S.E., Rashotte, A., Shipp, M.J., Muday, G.K., and Robertson, D. (2002) Mutations in the GPS loci in Arabidopsis disrupt the perception and/or signal transduction of gravitropic stimuli. Plant Physiology 130, 1426-1435. (pdf)