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Specific regulation and localization of very fast gravity regulated genes in Arabidopsis root apex.   J.M. Kimbrough, C.S. Brown1,2  H. Winter Sederoff1 Plant Gravitational Genomics Group, 1Dept. Botany, and 2Kenan Institute for Engineering, Technology &Science, NC State University, Raleigh, NC.

   The transcriptional profile in the Arabidopsis root apex has been investigated using full genome microarrays in a time course throughout the first hour after gravitropic stimulation (reorientation). Following gravitropic stimulation, significant changes in transcript abundance were detected prior to 2 minutes (Kimbrough et al., 2004). We observed a co regulated cluster of transcripts representing 5 functionally diverse genes exhibiting greater than 3 fold up-regulation prior to 2 minutes following reorientation. The molecular and physiological functions of these gene products are unknown. Identification of the transcriptional activators and repressors,  and  the functions of the proteins of those gravity-specific, fast and transiently expressed genes will allow us to link signal transduction events to differential cell elongation and to determine key transcriptional regulators of the gravitropic response. Transcriptional activators that function within the short time we have described must be constitutive components of very early gravitropic signal transduction.

Kimbrough, J., Salinas-Mondragon, R., Boss, W.F., Brown, C.S., Winter Sederoff, H.(2004)  The fast and transient transcriptional network of gravity and mechanical stimulation in the Arabidopsis root apex. Plant Physiol. (In press).

(Supported by NASA: NAG2-1566)