Role of TCP transcription factors in regulating stomatal development in Arabidopsis thaliana

Rini, Rahiman and On Sun Lau
Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Blk S1A #07-08, 117557, Singapore

Stomatal pores of leaves facilitate gas exchange in plants and their development are controlled by varying environmental signals. In this study, we focused on characterizing the plant-specific TCP (TEOSINTE BRANCHED1, CYCLOIDEA, PROLIFERATING CELL FACTOR) family of transcriptional factors in stomatal development. In a yeast one-hybrid screen, we identified several TCPs as potential transcriptional regulators of STOMAGEN, which encodes a mesophyll-derived secreted peptide that promotes stomatal development. Upon ectopically expressing the TCPs, we found that it dramatically promotes stomatal development in the hypocotyl but only mildly in the cotyledons. This result also correlates with the up-regulation of the STOMAGEN transcripts, specifically in the hypocotyl of the ectopic expression lines. Further, reporter analyses showed that both TCPs and STOMAGEN are expressed in the sub-epidermal tissues of the hypocotyl and are induced by light. Thus, we propose that TCPs function in a tissue-specific manner and up-regulate STOMAGEN expression in the sub-epidermal cells of the hypocotyl to promote stomatal development.