SymRK defines a common genetic basis for plant root endosymbioses with arbuscular mycorrhiza fungi, rhizobia, and Frankiabacteria.
Root endosymbioses vitally contribute to plant nutrition and fitness worldwide. Nitrogen-fixing root nodulation, confined to four plant orders, encompasses two distinct types of associations, the interaction of legumes (Fabales) with rhizobia bacteria and actinorhizal symbioses, where the bacterial symbionts are actinomycetes of the genus Frankia. Although several genetic components of the host-symbiont interaction have been identified in legumes, the genetic basis of actinorhiza formation is unknown. Here, we show that the receptor-like kinase gene SymRK, which is required for nodulation in legumes, is also necessary for actinorhiza formation in the tree Casuarina glauca. This indicates that both types of nodulation symbiosis share genetic components. Like several other legume genes involved in the interaction with rhizobia, SymRK is also required for the interaction with arbuscular mycorrhiza (AM) fungi. We show that SymRK is involved in AM formation in C. glauca as well and can restore both nodulation and AM symbioses in a Lotus japonicus symrk mutant. Taken together, our results demonstrate that SymRK functions as a vital component of the genetic basis for both plant-fungal and plant-bacterial endosymbioses and is conserved between legumes and actinorhiza-forming Fagales.
Gherbi
Hassen
H
Equipe Rhizogenèse, Unité Mixte de Recherche Diversité et Adaptation des Plantes Cultivées (DIAPC), Institut de Recherche pour le Développement (IRD), 911 Avenue Agropolis, 34394 Montpellier Cedex 5, France.
Markmann
Katharina
K
Svistoonoff
Sergio
S
Estevan
Joan
J
Autran
Daphné
D
Giczey
Gabor
G
Auguy
Florence
F
Péret
Benjamin
B
Laplaze
Laurent
L
Franche
Claudine
C
Parniske
Martin
M
Bogusz
Didier
D
D040161:Frankia / Q000502:physiology*; D005816:Genetic Complementation Test; D000070116:Lotus / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000382:microbiology; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D038821:Mycorrhizae / Q000502:physiology*; D016366:Open Reading Frames / Q000235:genetics; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000302:isolation & purification; D018517:Plant Roots / Q000166:cytology / Q000201:enzymology* / Q000382:microbiology*; D030821:Plants, Genetically Modified; D011494:Protein Kinases / Q000302:isolation & purification / Q000378:metabolism*; D012231:Rhizobium / Q000502:physiology*; D053204:Root Nodules, Plant / Q000166:cytology / Q000201:enzymology / Q000382:microbiology; D013559:Symbiosis; D014197:Trees / Q000166:cytology / Q000201:enzymology / Q000382:microbiology
D010940:Plant Proteins; D011494:Protein Kinases