Activation ofYUCCA5by the Transcription Factor TCP4 Integrates Developmental and Environmental Signals to Promote Hypocotyl Elongation in Arabidopsis.
Cell expansion is an essential process in plant morphogenesis and is regulated by the coordinated action of environmental stimuli and endogenous factors, such as the phytohormones auxin and brassinosteroid. Although the biosynthetic pathways that generate these hormones and their downstream signaling mechanisms have been extensively studied, the upstream transcriptional network that modulates their levels and connects their action to cell morphogenesis is less clear. Here, we show that the miR319-regulated TCP (TEOSINTE BRANCHED1, CYCLODEA, PROLIFERATING CELL FACTORS) transcription factors, notably TCP4, directly activateYUCCA5transcription and integrate the auxin response to a brassinosteroid-dependent molecular circuit that promotes cell elongation inArabidopsis thalianahypocotyls. Furthermore, TCP4 modulates the common transcriptional network downstream to auxin-brassinosteroid signaling, which is also triggered by environmental cues, such as light, to promote cell expansion. Our study linksTCPfunction with the hormone response during cell morphogenesis and shows that developmental and environmental signals converge on a common transcriptional network to promote cell elongation.
Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India.
Krishna Reddy
KR
Challa
Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India.
Pooja
P
Aggarwal
Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India utpal@mcbl.iisc.ernet.in.
Utpal
http://orcid.org/0000-0002-5537-5876
U
Nath