Seminar Dr Yohan Coudert

Phyllotaxis, the regular arrangement of leaves around stems, is one of the most striking natural patterns and primary determinant of plant architecture. Similar phyllotactic patterns have been described in bryophytes and vascular plants, the two major land plant lineages. However, phylogenetic evidence and the fossil record suggests that leaves or leaf-like organs evolved multiple times independently during bryophyte and vascular plant diversification, implying that phyllotaxis arose by convergence in both lineages. Deciphering how the periodic emergence of leaves is coordinated in space and time at the apex of growing shoots is an enigma that has puzzled biologists, mathematicians and physicists for centuries. Most studies investigating the cellular and molecular basis of phyllotaxis have focused on ferns and angiosperms, leaving the mechanisms underpinning phyllotaxis in bryophytes largely unknown. In bryophytes, phyllotaxis arises from a single apical stem cell, raising questions about how asymmetric divisions of a single apical cell create phyllotactic patterns and whether associated genetic processes are shared across lineages. To address this fundamental problem, we use the moss Physcomitrium patens as a model system. I will present the quantitative imaging tools that we have developed to characterize phyllotaxis at multiple scales, both in wild-type and mutant genetic backgrounds, and discuss how these approaches have allowed us to pinpoint the molecular regulation of phyllotaxis patterning in moss.

Yohan Coudert, "Signalisation hormonale et développement" SIGNAL, RDP, Lyon

Invitation:  Patrick Laufs
"Transcription Factors and Architecture" FTA team


In connection with the research developed at the Institute Jean-Pierre Bourgin for Plant Sciences.