title: Recruitment and remodeling of an ancient gene regulatory network during land plant evolution.
abstract: The evolution of multicellular organisms was made possible by the evolution of underlying gene regulatory networks. In animals, the core of gene regulatory networks consists of kernels, stable subnetworks of transcription factors that are highly conserved in distantly related species. However, in plants it is not clear when and how kernels evolved. We show here that RSL (ROOT HAIR DEFECTIVE SIX-LIKE) transcription factors form an ancient land plant kernel controlling caulonema differentiation in the moss Physcomitrella patens and root hair development in the flowering plant Arabidopsis thaliana. Phylogenetic analyses suggest that RSL proteins evolved in aquatic charophyte algae or in early land plants, and have been conserved throughout land plant radiation. Genetic and transcriptional analyses in loss of function A. thaliana and P. patens mutants suggest that the transcriptional interactions in the RSL kernel were remodeled and became more hierarchical during the evolution of vascular plants. We predict that other gene regulatory networks that control development in derived groups of plants may have originated in the earliest land plants or in their ancestors, the Charophycean algae.
authors.affiliation: Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom.
authors.forename: Nuno D
authors.initials: ND
authors.lastname: Pires
authors.forename: Keke
authors.initials: K
authors.lastname: Yi
authors.forename: Holger
authors.initials: H
authors.lastname: Breuninger
authors.forename: Bruno
authors.initials: B
authors.lastname: Catarino
authors.forename: Benoît
authors.initials: B
authors.lastname: Menand
authors.forename: Liam
authors.initials: L
authors.lastname: Dolan
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics*; D019068:Bryopsida / Q000235:genetics*; D019143:Evolution, Molecular; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D053263:Gene Regulatory Networks / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D010802:Phylogeny; D018517:Plant Roots / Q000235:genetics / Q000502:physiology; D016415:Sequence Alignment; D013045:Species Specificity
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; C520581:RSL1 protein, Arabidopsis
keywords: auxin; bHLH; gametophyte; protonema; sporophyte