title: Strigolactones inhibit caulonema elongation and cell division in the moss Physcomitrella patens.
abstract: In vascular plants, strigolactones (SLs) are known for their hormonal role and for their role as signal molecules in the rhizosphere. SLs are also produced by the moss Physcomitrella patens, in which they act as signaling factors for controlling filament extension and possibly interaction with neighboring individuals. To gain a better understanding of SL action at the cellular level, we investigated the effect of exogenously added molecules (SLs or analogs) in moss growth media. We used the previously characterized Ppccd8 mutant that is deficient in SL synthesis and showed that SLs affect moss protonema extension by reducing caulonema cell elongation and mainly cell division rate, both in light and dark conditions. Based on this effect, we set up bioassays to examine chemical structure requirements for SL activity in moss. The results suggest that compounds GR24, GR5, and 5-deoxystrigol are active in moss (as in pea), while other analogs that are highly active in the control of pea branching show little activity in moss. Interestingly, the karrikinolide KAR1, which shares molecular features with SLs, did not have any effect on filament growth, even though the moss genome contains several genes homologous to KAI2 (encoding the KAR1 receptor) and no canonical homologue to D14 (encoding the SL receptor). Further studies should investigate whether SL signaling pathways have been conserved during land plant evolution.
authors.affiliation: Institut Jean-Pierre Bourgin, UMR1318 Institut National de la Recherche Agronomique-AgroParisTech, Versailles, France.
authors.forename: Beate
authors.initials: B
authors.lastname: Hoffmann
authors.affiliation: Institut Jean-Pierre Bourgin, UMR1318 Institut National de la Recherche Agronomique-AgroParisTech, Versailles, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Proust
authors.affiliation: Institut Jean-Pierre Bourgin, UMR1318 Institut National de la Recherche Agronomique-AgroParisTech, Versailles, France.
authors.forename: Katia
authors.initials: K
authors.lastname: Belcram
authors.affiliation: Institut Jean-Pierre Bourgin, UMR1318 Institut National de la Recherche Agronomique-AgroParisTech, Versailles, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Labrune
authors.affiliation: Institut Jean-Pierre Bourgin, UMR1318 Institut National de la Recherche Agronomique-AgroParisTech, Versailles, France,; Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles, UPR2301 CNRS, Gif-sur-Yvette, France.
authors.forename: François-Didier
authors.initials: FD
authors.lastname: Boyer
authors.affiliation: Institut Jean-Pierre Bourgin, UMR1318 Institut National de la Recherche Agronomique-AgroParisTech, Versailles, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Rameau
authors.affiliation: Institut Jean-Pierre Bourgin, UMR1318 Institut National de la Recherche Agronomique-AgroParisTech, Versailles, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Bonhomme
mesh_terms: D044002:Bryophyta / Q000187:drug effects* / Q000254:growth & development; D035264:Flowers / Q000187:drug effects / Q000254:growth & development; D007783:Lactones / Q000737:chemistry / Q000494:pharmacology*; D008027:Light; D009154:Mutation; D059828:Plant Cells / Q000187:drug effects* / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: C528323:5-deoxystrigol; C507382:GR24 compound; D007783:Lactones; D010937:Plant Growth Regulators; D010940:Plant Proteins