TCP transcription factors regulate the gene network for differentiation of shoot lateral organs in Arabidopsis

Abstract

Plant cells have extraordinary pluripotency, but they are differentiated into a specific organ in a defined position and timing. Arabidopsis TCP3 regulates differentiation of cells in shoot lateral organs. We reported that expression of chimeric TCP3 repressor (TCP3SRDX), which was a dominant negative form of TCP3, induced wavy shaped organs and formation of shoots on cotyledons. Expression of TCP3SRDX induced ectopic expression of boundary-specific genes including CUC genes in association with reduction of accumulation of miR164, whose product cleaves CUC transcripts. To clarify the role of TCP3 in the negative regulation of CUC genes, we used a system for chemical induction of TCP3SRDX in transgenic plants and found that genes downstream of TCP3 are involved in transcription, auxin responses and regulation of chloroplast function. Transient gene expression assay indicated that TCP3SRDX suppressed the promoter activity of these genes. We discuss possible gene network regulated by TCP3.