The phytohormone gibberellic acid (GA) is involved in the regulation of important aspects of plant growth and development including germination, stem elongation and the control of flowering time. GA responses require the GA-dependent degradation of the DELLA repressor proteins. DELLA proteins (RGA and GAI in Arabidopsis) belong to the group of GRAS proteins. GRAS proteins have been suggested to act as transcriptional regulators, though direct binding to specific DNA sequences has not been reported yet. Using chromatin immunoprecipitation experiments (ChIP), we have recently demonstrated that the GRAS protein SCARECROWLIKE-14 is recruited to specific DNA sequences by DNA-bound bZIP transcription factors of the TGA family. Having established a reliable ChIP protocol for GRAS proteins we propose to identify target promoters for GAI and RGA using ChIP analysis in combination with the hybridization of ChIP enriched sequences to a tiling promoter array (ChIP-chip). The project has the potential to close an important gap in understanding GA signalling in plants.
DFG Programme
Research Grants
