Gibberellins are involved in nodulation of Sesbania rostrata.
Upon submergence, Azorhizobium caulinodans infects the semiaquatic legume Sesbania rostrata via the intercellular crack entry process, resulting in lateral root-based nodules. A gene encoding a gibberellin (GA) 20-oxidase, SrGA20ox1, involved in GA biosynthesis, was transiently up-regulated during lateral root base nodulation. Two SrGA20ox1 expression patterns were identified, one related to intercellular infection and a second observed in nodule meristem descendants. The infection-related expression pattern depended on bacterially produced nodulation (Nod) factors. Pharmacological studies demonstrated that GAs were involved in infection pocket and infection thread formation, two Nod factor-dependent events that initiate lateral root base nodulation, and that they were also needed for nodule primordium development. Moreover, GAs inhibited the root hair curling process. These results show that GAs are Nod factor downstream signals for nodulation in hydroponic growth.
Lievens
Sam
S
Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology, Ghent University, B-9052 Gent, Belgium.
Goormachtig
Sofie
S
Den Herder
Jeroen
J
Capoen
Ward
W
Mathis
René
R
Hedden
Peter
P
Holsters
Marcelle
M
D020599:Azorhizobium caulinodans / Q000502:physiology; D001692:Biological Transport; D020171:Botrytis; D002716:Chlormequat / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D005875:Gibberellins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D049931:Sesbania / Q000254:growth & development / Q000382:microbiology / Q000502:physiology*; D014230:Triazoles / Q000494:pharmacology; D015854:Up-Regulation / Q000235:genetics
D005875:Gibberellins; D008070:Lipopolysaccharides; C410036:Nod factor , Azorhizobium caulinodans; D012333:RNA, Messenger; D014230:Triazoles; C053370:paclobutrazol; D002716:Chlormequat