Design principles of a minimal auxin response system ($) (BioRxiv)

Auxin signaling components are evolutionarily conserved across the land plants and the duplication events in these regulators enabled complexity in development. Auxin regulated developmental programming occurs through the ARF (AUXIN RESPONSE FACTORS) transcriptional factors. Marchantia polymorpha serves as an ideal system to understand ARF activity owing to its simpler genome complexity. In their previous work, Weijer’s Lab has shown the importance of the three ARF protein in Mpolymorpha development. In this paper, Kato et al., have identified the mechanism by which A-ARF and B-ARF define developmental programming by regulating the expression of downstream auxin-responsive genes. Until recently the precise mechanism by which the class B- ARFs can repress gene expression is unknown. Using M. polymorpha, the authors have shown that B-ARF can act antagonistically by binding to A-ARF target sites. This resolves one more piece in the large puzzle of auxin signaling and activation of gene expression for plant development. Summary by Suresh Damodaran. bioRxiv, DOI :