You are receiving this e-mail because you subscribed to our seminars announcements and reminders service at [ https://maillist.psb.ugent.be/mailman/listinfo/seminars | https://maillist.psb.ugent.be/mailman/listinfo/seminars ] . '' Vein Patterning by Coordinated Polar Cell-Behavior '' Prof Enrico Scarpella Department of Biological Sciences University of Alberta CANADA Thursday, April 28, 2022 11:00 To form tissue networks, animal cells migrate along specific directions and interact through proteins protruding from specific segments of their plasma membranes. Plant cells can do neither, yet plants form vein networks. How plants do so is unclear, but the prevailing hypothesis proposes that GNOM — a regulator of membrane trafficking — positions PIN-FORMED auxin transporters to specific segments of the plasma membrane; the resulting cell-to-cell, polar transport of auxin would induce vein formation. Contrary to predictions of the hypothesis, we find that vein formation occurs in the absence of PIN-FORMED auxin transporters; that the residual auxin-transport-independent vein-patterning activity relies on auxin signaling; and that a GNOM -dependent signal acts upstream of both auxin transport and auxin signaling to induce vein formation. Nevertheless, plants inhibited in both auxin transport and auxin signaling still form veins. Patterning of vascular cells into veins is instead prevented in the absence of GNOM function, suggesting the existence of at least one more GNOM -dependent vein-patterning pathway. Our fundings suggest that such a pathway depends on the movement of an auxin-dependent signal through the plasmodesmata (PDs) intercellular channels. PD permeability is high where veins are forming, lowers between veins and nonvascular tissues, but remains high between vein cells. Impaired ability to regulate PD aperture leads to defects in auxin transport and signaling, ultimately leading to vein patterning defects that are enhanced by inhibition of auxin transport or signaling. GNOM controls PD aperture regulation, and simultaneous inhibition of auxin signaling, auxin transport, and regulated PD aperture phenocopies loss of GNOM function. Therefore, veins are patterned by the coordinated action of three GNOM -dependent pathways: auxin signaling, polar auxin transport, and movement of an auxin-dependent signal through PDs. Such control is an unprecedented mechanism of tissue network formation in multicellular organisms. Jozef Schell seminar room Technologiepark 71 - 9052 Invited by Prof Dirk Inzé and Prof Bert De Rybel If you do not wish to receive this information anymore, please unsubscribe from future mailings at [ https://maillist.psb.ugent.be/mailman/listinfo/seminars | https://maillist.psb.ugent.be/mailman/listinfo/seminars ] Genome editing, cutting-edge technology for a sustainable agriculture VIB-UGent Center for Plant Systems Biology Ghent University Technologiepark-Zwijnaarde 71 9052 Ghent-Belgium Phone: +32(0)9 331 38 00 [ http://www.psb.vib-ugent.be/ | https://www.psb.ugent.be/ ]