title: Structure-function relations of strigolactone analogs: activity as plant hormones and plant interactions.
abstract: Strigolactones (SLs) have several functions as signaling molecules in their interactions with symbiotic arbuscular mycorrhizal (AM) fungi and the parasitic weeds Orobanche and Striga. SLs are also a new class of plant hormone regulating plant development. In all three organisms, a specific and sensitive receptor-mediated perception system is suggested. By comparing the activity of synthetic SL analogs on Arabidopsis root-hair elongation, Orobanche aegyptiaca seed germination, and hyphal branching of the AM fungus Glomus intraradices, we found that each of the tested organisms differs in its response to the various examined synthetic SL analogs. Structure-function relations of the SL analogs suggest substitutions on the A-ring as the cause of this variation. Moreover, the description of competitive antagonistic analogs suggests that the A-ring of SL can affect not only affinity to the receptor, but also the molecule's ability to activate it. The results support the conclusion that Arabidopsis, Orobanche, and AM fungi possess variations in receptor sensitivity to SL analogs, probably due to variation in SL receptors among the different species.
authors.affiliation: Institute of Plant Sciences,  ARO, Volcani Center, Bet Dagan,  Israel.
authors.forename: Maja
authors.initials: M
authors.lastname: Cohen
authors.forename: Cristina
authors.initials: C
authors.lastname: Prandi
authors.forename: Ernesto G
authors.initials: EG
authors.lastname: Occhiato
authors.forename: Silvia
authors.initials: S
authors.lastname: Tabasso
authors.forename: Smadar
authors.initials: S
authors.lastname: Wininger
authors.forename: Nathalie
authors.initials: N
authors.lastname: Resnick
authors.forename: Yosef
authors.initials: Y
authors.lastname: Steinberger
authors.forename: Hinanit
authors.initials: H
authors.lastname: Koltai
authors.forename: Yoram
authors.initials: Y
authors.lastname: Kapulnik
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D017360:Arabidopsis / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D002227:Carbazoles / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism* / Q000494:pharmacology; D018525:Germination / Q000187:drug effects; D025301:Hyphae / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D038821:Mycorrhizae / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D031672:Orobanche / Q000187:drug effects / Q000254:growth & development; D010937:Plant Growth Regulators / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism* / Q000494:pharmacology; D012639:Seeds / Q000187:drug effects / Q000254:growth & development; D013329:Structure-Activity Relationship
chemical_list: D002227:Carbazoles; D010937:Plant Growth Regulators; D015107:4-Butyrolactone