The Medicago truncatula lysin [corrected] motif-receptor-like kinase gene family includes NFP and new nodule-expressed genes.
Rhizobial Nod factors are key symbiotic signals responsible for starting the nodulation process in host legume plants. Of the six Medicago truncatula genes controlling a Nod factor signaling pathway, Nod Factor Perception (NFP) was reported as a candidate Nod factor receptor gene. Here, we provide further evidence for this by showing that NFP is a lysin [corrected] motif (LysM)-receptor-like kinase (RLK). NFP was shown both to be expressed in association with infection thread development and to be involved in the infection process. Consistent with deviations from conserved kinase domain sequences, NFP did not show autophosphorylation activity, suggesting that NFP needs to associate with an active kinase or has unusual functional characteristics different from classical kinases. Identification of nine new M. truncatula LysM-RLK genes revealed a larger family than in the nonlegumes Arabidopsis (Arabidopsis thaliana) or rice (Oryza sativa) of at least 17 members that can be divided into three subfamilies. Three LysM domains could be structurally predicted for all M. truncatula LysM-RLK proteins, whereas one subfamily, which includes NFP, was characterized by deviations from conserved kinase sequences. Most of the newly identified genes were found to be expressed in roots and nodules, suggesting this class of receptors may be more extensively involved in nodulation than was previously known.
Arrighi
Jean-François
JF
Laboratoire des Interactions Plantes-Microorganismes, Institut National de la Recherche Agronomique-Centre National de la Recherche Scientifique, Unité Mixte de Recherche 441/2594, 31326 Castanet-Tolosan, France.
Barre
Annick
A
Ben Amor
Besma
B
Bersoult
Anne
A
Soriano
Lidia Campos
LC
Mirabella
Rossana
R
de Carvalho-Niebel
Fernanda
F
Journet
Etienne-Pascal
EP
Ghérardi
Michèle
M
Huguet
Thierry
T
Geurts
René
R
Dénarié
Jean
J
Rougé
Pierre
P
Gough
Clare
C
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D020440:Gene Duplication; D015870:Gene Expression; D018745:Genome, Plant; D008239:Lysine / Q000737:chemistry; D046913:Medicago truncatula / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family; D010766:Phosphorylation; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D016962:Sinorhizobium meliloti / Q000502:physiology*; D013559:Symbiosis / Q000235:genetics / Q000502:physiology
D010940:Plant Proteins; D011494:Protein Kinases; D008239:Lysine