“Regulation of organogenesis and tissue patterning during postembryonic development in Arabidopsis thaliana”

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Thursday 18 January 2018, 11:00 - 12:30

 
ABSTRACT

Plants develop continuously through the formation and growth of organs. Organogenesis after embryogenesis starts with the formation of organ founder cells, which have the developmental potential –pluripotency-of giving rise to all distinct tissues which make up an organ. Positioning and specification of root organ founder cells is dependent on oscillating gene expression, which is part of a developmental clock, the Lateral Root Clock. To gain further insight into morphogenetic regulators of oscillating gene expression and founder cell specification we have generated plants carrying specific cell identity markers and have performed a mutagenesis screen. Analyses of one of these mutants show dependence on auxin import to set gene expression oscillations and indicate additional requirement of the transgolgi network to specify founder cell identity through GTP-dependent proteins. In other of these mutants, which we named potent, many pericycle cells change their identity becoming organ founder cells, which results in overproduction of lateral roots. POTENT is degraded by auxin and interacts with oscillating transcription factors, functioning as a transcriptional repressor. Our results indicate that POTENT integrates auxin signaling into oscillating gene expression through a double repression mechanism to set the pace of organ founder cell positioning.

Following a different approach, we are reconstructing a transcriptional map of postembryonic organogenesis. We have identified markers expressed at specific times of lateral root formation and performed fluorescent activated cell sorting coupled with RNA sequencing. Analysis of these data recapitulates expression of known regulators of lateral root formation and shows involvement of specific cellular functions at certain stages of organogenesis, identifying novel factors. Parallelisms with other morphogenetic mechanisms will be examined.

Location Jozef Schell Seminar Room
Contact Dr Miguel Moreno-Risueño
Center for Plant Biotechnology and Genomics (UPM-INIA)
Department of Biotechnology and Plant Biology
Polytechnic University of Madrid
SPAIN