Control of root development by miR396 and GROWTH-REGULATING FACTOR transcription factors

ERCOLI, MA FLORENCIA; BREAKFIELD, NATALIE; COOLS, TOON; PALATNIK, JAVIER F; DEBERNARDI, JUAN MANUEL; SABATINI, MARTIN; BENFEY, PHILIP; RODRIGUEZ, RAMIRO ESTEBAN; MECCHIA, MARTIN; DE VEYLDER, LIEVEN

Buenos Aires

Simposio; Simposio Fronteras en Biociencia 2; 2016

IBIOBA - Max Planck

Plants rely on stem cells for the generation of the different cell types that constitute their body parts. They are located within specific cellular contexts referred to as stem cell niches. While stem cells divide slowly to generate different cell types, their progeny generally undergo rapid, transient amplifying cell divisions to ensure enough cells for organ growth. Later on, cells differentiate to their final size, shape and function. Therefore, a clear gradient is detectable along the root axis which facilitates studies on cell fate determination. During the last years, studies mostly performed with Arabidopsis have uncovered groups of transcription factors, phytohormones and signaling peptides that interact to maintain these consecutive developmental zones.The GROWTH-REGULATING FACTOR(GRF) family of transcription factors is a small gene family found in land plants defined by the presence of the WRC and QLQ protein domains. GRF transcripts are post transcriptionally regulated by microRNA miR396. As a result, these transcription factors are expressed preferentially in proliferating tissues where they promote cell division. Here we describe the role of GRFs and miR396 in root development. We found that the miR396/GRF regulatory module function in transit amplifying cells to repress stem cell-associated genes. Detailed analysis also showed that high miRNA levels affect cell elongation in roots. Altogether, the results provide insights into the participation of the miRNA-GRF regulatory network in root development.