Seminar Dr Hirotaka Kato

Plant cells are immobile due to their rigid cell walls, and thus the regulation of the cell division plane is crucial for tissue organization and morphogenesis. The plant hormone auxin plays key roles in the transition from symmetric to asymmetric divisions, yet the complexity of auxin signaling in angiosperms hinders our understanding of how auxin controls cell division orientation. To address this, we use the liverwort Marchantia polymorpha, which has low genetic redundancy and occupies a key evolutionary position as a bryophyte that diverged from vascular plants about 450 million years ago. M. polymorpha possesses a minimal yet functional auxin signaling system that orchestrates diverse developmental processes, making it an ideal model for studying the evolution of auxin-mediated development [1-3]. Comparative transcriptome analyses across bryophytes and ferns identified WIP, an auxin-responsive transcription factor gene conserved in land plants [4]. Genetic studies revealed that WIP regulates the density of gemma cup formation by forming a negative feedback loop with the auxin biosynthesis pathway. In addition, we isolated an air-chamberless mutant, zunberabo (zun), whose causal gene encodes a TON1-recruiting motif (TRM) protein, a known regulator of cell division plane control in angiosperms. Confocal imaging showed that zun exhibits abnormal apical cell morphology and division patterns. Notably, both gemma cups and air chambers arise from the dorsal epidermis of the thallus, and previous studies suggest that the regulation of the cell division plane contributes to the fate determination of these organs. In this seminar, I will present our recent findings and discuss possible links between auxin signaling, cell division plane regulation, and organ fate specification in land plants.

Reférences 
1 -  H Kato et al., Auxin-Mediated Transcriptional System with a Minimal Set of Components Is Critical for Morphogenesis through the Life Cycle in Marchantia polymorpha. PLoS Genet 11, e1005084. 2015. doi: https://doi.org/10.1371/journal.pgen.1005084
2 -  H Kato et al., The Roles of the Sole Activator-Type Auxin Response Factor in Pattern Formation of Marchantia polymorpha. Plant Cell Physiol 58, 1642-1651. 2017. doi: https://doi.org/10.1093/pcp/pcx095
3 - H Kato et al., Design principles of a minimal auxin response system. Nat Plants 6, 473-482. 2020. doi: https://doi.org/10.1038/s41477-020-0662-y
4 - S K Mutte, H Kato et al., Origin and evolution of the nuclear auxin response system. Elife 7, e33399. 2018. doi: https://elifesciences.org/articles/33399 

Hirotaka Kato, Hirotaka Kato's Lab, Ehime University, Matsuyama, Japan

Invitation : David Bouchez

"Spatial Control of Cell Division" SPACE team


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