A gain-of-function mutation in a cytokinin receptor triggers spontaneous root nodule organogenesis.
Legume root nodules originate from differentiated cortical cells that reenter the cell cycle and form organ primordia. We show that perception of the phytohormone cytokinin is a key element in this switch. Mutation of a Lotus japonicus cytokinin receptor gene leads to spontaneous development of root nodules in the absence of rhizobia or rhizobial signal molecules. The mutant histidine kinase receptor has cytokinin-independent activity and activates an Escherichia coli two-component phosphorelay system in vivo. Mutant analysis shows that cytokinin signaling is required for cell divisions that initiate nodule development and defines an autoregulated process where cytokinin induction of nodule stem cells is controlled by shoots.
Tirichine
Leïla
L
Laboratory of Gene Expression, Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10, DK-8000 Aarhus C, Denmark.
Sandal
Niels
N
Madsen
Lene H
LH
Radutoiu
Simona
S
Albrektsen
Anita S
AS
Sato
Shusei
S
Asamizu
Erika
E
Tabata
Satoshi
S
Stougaard
Jens
J
D000483:Alleles; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001593:Benzyl Compounds; D002118:Calcium / Q000378:metabolism; D002455:Cell Division; D003583:Cytokinins / Q000378:metabolism* / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D000071677:Histidine Kinase; D007701:Kinetin / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000378:metabolism; D000070116:Lotus / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D018519:Meristem / Q000166:cytology; D008969:Molecular Sequence Data; D009154:Mutation; D009586:Nitrogen Fixation; D018517:Plant Roots / Q000166:cytology / Q000378:metabolism; D030821:Plants, Genetically Modified; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011687:Purines; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D053204:Root Nodules, Plant / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D015398:Signal Transduction; D014170:Transformation, Genetic
D001593:Benzyl Compounds; D003583:Cytokinins; D008070:Lipopolysaccharides; D011687:Purines; D011956:Receptors, Cell Surface; D011494:Protein Kinases; D000071677:Histidine Kinase; C480551:benzylaminopurine; D007701:Kinetin; D002118:Calcium