title: Differential activity of Striga hermonthica seed germination stimulants and Gigaspora rosea hyphal branching factors in rice and their contribution to underground communication.
abstract: Strigolactones (SLs) trigger germination of parasitic plant seeds and hyphal branching of symbiotic arbuscular mycorrhizal (AM) fungi. There is extensive structural variation in SLs and plants usually produce blends of different SLs. The structural variation among natural SLs has been shown to impact their biological activity as hyphal branching and parasitic plant seed germination stimulants. In this study, rice root exudates were fractioned by HPLC. The resulting fractions were analyzed by MRM-LC-MS to investigate the presence of SLs and tested using bioassays to assess their Striga hermonthica seed germination and Gigaspora rosea hyphal branching stimulatory activities. A substantial number of active fractions were revealed often with very different effect on seed germination and hyphal branching. Fractions containing (-)-orobanchol and ent-2'-epi-5-deoxystrigol contributed little to the induction of S. hermonthica seed germination but strongly stimulated AM fungal hyphal branching. Three SLs in one fraction, putative methoxy-5-deoxystrigol isomers, had moderate seed germination and hyphal branching inducing activity. Two fractions contained strong germination stimulants but displayed only modest hyphal branching activity. We provide evidence that these stimulants are likely SLs although no SL-representative masses could be detected using MRM-LC-MS. Our results show that seed germination and hyphal branching are induced to very different extents by the various SLs (or other stimulants) present in rice root exudates. We propose that the development of rice varieties with different SL composition is a promising strategy to reduce parasitic plant infestation while maintaining symbiosis with AM fungi.
authors.affiliation: Laboratory of Plant Physiology, Wageningen University, Wageningen, the Netherlands.
authors.forename: Catarina
authors.initials: C
authors.lastname: Cardoso
authors.affiliation: Laboratory of Plant Physiology, Wageningen University, Wageningen, the Netherlands.
authors.forename: Tatsiana
authors.initials: T
authors.lastname: Charnikhova
authors.affiliation: Laboratory of Plant Physiology, Wageningen University, Wageningen, the Netherlands.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Jamil
authors.affiliation: Laboratoire de Recherche en Sciences Végétales, Unité Mixte de Recherche (UMR) 5546, Université de Toulouse, Castanet-Tolosan, France; Laboratoire de Recherche en Sciences Végétales, Unité Mixte de Recherche (UMR) 5546, Centre National de la Recherche Scientifique (CNRS), Castanet-Tolosan, France.
authors.forename: Pierre-Marc
authors.initials: PM
authors.lastname: Delaux
authors.affiliation: Laboratory of Plant Physiology, Wageningen University, Wageningen, the Netherlands; Centre for Biosystems Genomics, Wageningen, the Netherlands.
authors.forename: Francel
authors.initials: F
authors.lastname: Verstappen
authors.affiliation: Laboratory of Plant Physiology, Wageningen University, Wageningen, the Netherlands.
authors.forename: Maryam
authors.initials: M
authors.lastname: Amini
authors.affiliation: Laboratoire de Recherche en Sciences Végétales, Unité Mixte de Recherche (UMR) 5546, Université de Toulouse, Castanet-Tolosan, France; Laboratoire de Recherche en Sciences Végétales, Unité Mixte de Recherche (UMR) 5546, Centre National de la Recherche Scientifique (CNRS), Castanet-Tolosan, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Lauressergues
authors.affiliation: Laboratory of Plant Physiology, Wageningen University, Wageningen, the Netherlands; Bioscience, Plant Research International, Wageningen, the Netherlands.
authors.forename: Carolien
authors.initials: C
authors.lastname: Ruyter-Spira
authors.affiliation: Laboratory of Plant Physiology, Wageningen University, Wageningen, the Netherlands; Centre for Biosystems Genomics, Wageningen, the Netherlands.
authors.forename: Harro
authors.initials: H
authors.lastname: Bouwmeester
mesh_terms: D018525:Germination; D055137:Glomeromycota; D009154:Mutation; D012275:Oryza; D018517:Plant Roots / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000382:microbiology; D012639:Seeds; D034362:Striga; D013559:Symbiosis