title: Auxin signaling in algal lineages: fact or myth?
abstract: Auxin is of major importance throughout the life cycle of a plant, affecting several physiological and developmental processes, such as cell expansion and division. However, the evolutionary time point at which auxin became involved in such diverse processes is currently unclear. Despite some controversy, numerous reports demonstrate the presence of auxin in algal lineages and its effects on algal development, suggesting an early evolutionary origin of auxin-dependent mechanisms. Here, we review these reports and discuss in silico analyses of auxin signaling components. It seems that, at least in microalgae, the assumed major components of auxin signaling in land plants are absent. However, these microalgae might have alternative auxin signaling pathways that could account for their responses to auxin.
authors.affiliation: Center for Plant Molecular Biology (ZMBP), Developmental Genetics, Tübingen University, Auf der Morgenstelle 3, D-72076 Tübingen, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Lau
authors.forename: Ning
authors.initials: N
authors.lastname: Shao
authors.forename: Ralph
authors.initials: R
authors.lastname: Bock
authors.forename: Gerd
authors.initials: G
authors.lastname: Jürgens
authors.forename: Ive
authors.initials: I
authors.lastname: De Smet
mesh_terms: D020418:Algal Proteins / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D056890:Eukaryota / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D010944:Plants / Q000145:classification / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
chemical_list: D020418:Algal Proteins; D007210:Indoleacetic Acids; D010940:Plant Proteins