Cell-by-cell dissection of phloem development links a maturation gradient to cell specialization
Pawel Roszak, Jung‐ok Heo, Bernhard Blob, Koichi Toyokura, Yuki Sugiyama, María Angels de Luis Balaguer, Winnie Lau, Fiona Hamey, Jacopo Cirrone, Ewelina Madej, Alida Melissa Bouatta, Xin Wang, Marjorie Guichard, Robertas Ursache, Hugo Tavares, Kevin Verstaen, Jos R. Wendrich, Charles W. Melnyk, Yoshihisa Oda, Dennis Shasha, Sebastian E. Ahnert, Yvan Saeys, Bert De Rybel, Renze Heidstra, Ben Scheres, Guido Großmann, Ari Pekka Mähönen, Philipp Denninger, Berthold Göttgens, Rosangela Sozzani, Kenneth D. Birnbaum, Ykä Helariutta
Abstract
root. PHLOEM EARLY DNA-BINDING-WITH-ONE-FINGER (PEAR) transcription factors mediate lineage bifurcation by activating guanosine triphosphatase signaling and prime a transcriptional differentiation program. This program is initially repressed by a meristem-wide gradient of PLETHORA transcription factors. Only the dissipation of PLETHORA gradient permits activation of the differentiation program that involves mutual inhibition of early versus late meristem regulators. Thus, for phloem development, broad maturation gradients interface with cell-type-specific transcriptional regulators to stage cellular differentiation.