Hélène Robert-Boisivon, Masaryk University in Brno, Czech Republic
Claudia Köhler, VBSG, SLU
Lecture hall A281, Uppsala BioCentre, Ultuna
14:00 - 15:00
Local auxin biosynthesis: a trigger for embryo patterning in Arabidopsis thaliana

Establishment of embryonic axis foreshadows the main body axis of both adult plants and animals, but underlying mechanisms are considered distinct. Plants utilize directional, cell-to-cell transport of the growth hormone auxin to generate an asymmetric auxin response that specifies embryonic apical-basal axis. The auxin flow directionality depends on the polarized subcellular localization of PIN-FORMED (PIN) auxin transporters. It remains unknown, which mechanisms and spatial cues guide cell polarization and axis orientation in early embryos. I will present novel insights into the formation of embryonic axis in Arabidopsis by the identification of a crucial role of the local tryptophan-dependent auxin biosynthesis. My talk will discuss how precise spatio-temporal control of distinct auxin sources provides a necessary, non-cell autonomous trigger for coordinated cell polarization and subsequent apical-basal axis orientation during embryogenesis, and presumably also other polarization events during postembryonic plant life.