title: The role of bZIP transcription factors in green plant evolution: adaptive features emerging from four founder genes.
abstract: BACKGROUND
  Transcription factors of the basic leucine zipper (bZIP) family control important processes in all eukaryotes. In plants, bZIPs are regulators of many central developmental and physiological processes including photomorphogenesis, leaf and seed formation, energy homeostasis, and abiotic and biotic stress responses. Here we performed a comprehensive phylogenetic analysis of bZIP genes from algae, mosses, ferns, gymnosperms and angiosperms.
  
  
  RESULTS
  We identified 13 groups of bZIP homologues in angiosperms, three more than known before, that represent 34 Possible Groups of Orthologues (PoGOs). The 34 PoGOs may correspond to the complete set of ancestral angiosperm bZIP genes that participated in the diversification of flowering plants. Homologous genes dedicated to seed-related processes and ABA-mediated stress responses originated in the common ancestor of seed plants, and three groups of homologues emerged in the angiosperm lineage, of which one group plays a role in optimizing the use of energy.
  
  
  CONCLUSIONS
  Our data suggest that the ancestor of green plants possessed four bZIP genes functionally involved in oxidative stress and unfolded protein responses that are bZIP-mediated processes in all eukaryotes, but also in light-dependent regulations. The four founder genes amplified and diverged significantly, generating traits that benefited the colonization of new environments.
authors.affiliation: Centro de Biologia Molecular e Engenharia Genética, Departamento de Genética e Evolução, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, Brazil.
authors.forename: Luiz Gustavo Guedes
authors.initials: LG
authors.lastname: Corrêa
authors.forename: Diego Mauricio
authors.initials: DM
authors.lastname: Riaño-Pachón
authors.forename: Carlos Guerra
authors.initials: CG
authors.lastname: Schrago
authors.forename: Renato Vicentini
authors.initials: RV
authors.lastname: dos Santos
authors.forename: Bernd
authors.initials: B
authors.lastname: Mueller-Roeber
authors.forename: Michel
authors.initials: M
authors.lastname: Vincentz
mesh_terms: D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000502:physiology*; D019143:Evolution, Molecular; D018703:Founder Effect; D005788:Gene Pool; D017343:Genes, Plant; D006580:Genetic Carrier Screening; D014644:Genetic Variation; D019684:Magnoliopsida / Q000235:genetics; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology*; D010944:Plants / Q000145:classification / Q000235:genetics*
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D010940:Plant Proteins