The NFP locus of Medicago truncatula controls an early step of Nod factor signal transduction upstream of a rapid calcium flux and root hair deformation.
Establishment of the Rhizobium-legume symbiosis depends on a molecular dialogue, in which rhizobial nodulation (Nod) factors act as symbiotic signals, playing a key role in the control of specificity of infection and nodule formation. Using nodulation-defective (Nod-) mutants of Medicago truncatula to study the mechanisms controlling Nod factor perception and signalling, we have previously identified five genes that control components of a Nod factor-activated signal transduction pathway. Characterisation of a new M. truncatula Nod- mutant led to the identification of the Nod Factor Perception (NFP) locus. The nfp mutant has a novel phenotype among Nod- mutants of M. truncatula, as it does not respond to Nod factors by any of the responses tested. The nfp mutant thus shows no rapid calcium flux, the earliest detectable Nod factor response of wild-type plants, and no root hair deformation. The nfp mutant is also deficient in Nod factor-induced calcium spiking and early nodulin gene expression. While certain genes controlling Nod factor signal transduction also control the establishment of an arbuscular mycorrhizal symbiosis, the nfp mutant shows a wild-type mycorrhizal phenotype. These data indicate that the NFP locus controls an early step of Nod factor signal transduction, upstream of previously identified genes and specific to nodulation.
Amor
Besma Ben
BB
Laboratoire des Interactions Plantes-Microorganismes, INRA-CNRS, BP 27, 31326 Castanet-Tolosan, France.
Shaw
Sidney L
SL
Oldroyd
Giles E D
GE
Maillet
Fabienne
F
Penmetsa
R Varma
RV
Cook
Douglas
D
Long
Sharon R
SR
Dénarié
Jean
J
Gough
Clare
C
D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D032461:Chromosomes, Plant / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D005816:Genetic Complementation Test; D036341:Intercellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides / Q000494:pharmacology*; D029902:Medicago / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D010455:Peptides; D010641:Phenotype; D020161:Physical Chromosome Mapping; D018517:Plant Roots / Q000187:drug effects* / Q000254:growth & development; D030821:Plants, Genetically Modified; D012231:Rhizobium / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects*; D014862:Wasp Venoms / Q000494:pharmacology
D036341:Intercellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides; D010455:Peptides; D014862:Wasp Venoms; C037500:mastoparan; D002118:Calcium