Rhizobium leguminosarum bv. viciae genotypes interact with pea plants in developmental responses of nodules, roots and shoots.
The variability of the developmental responses of two contrasting cultivars of pea (Pisum sativum) was studied in relation to the genetic diversity of their nitrogen-fixing symbiont Rhizobium leguminosarum bv. viciae. A sample of 42 strains of pea rhizobia was chosen to represent 17 genotypes predominating in indigenous rhizobial populations, the genotypes being defined by the combination of haplotypes characterized with rDNA intergenic spacer and nodD gene regions as markers. We found contrasting effects of the bacterial genotype, especially the nod gene type, on the development of nodules, roots and shoots. A bacterial nod gene type was identified that induced very large, branched nodules, smaller nodule numbers, high nodule biomass, but reduced root and aerial part development. The plants associated with this genotype accumulated less N in shoots, but N concentration in leaves was not affected. The results suggest that the plant could not control nodule development sustaining the energy demand for nodule functioning and its optimal growth. The molecular and physiological mechanisms that may be involved are discussed.
Laguerre
Gisèle
G
INRA, UMR1229 Microbiologie du Sol et de l'Environnement, BP 86510, F-21065 Dijon Cedex, France.|Present address: USC1242 INRA, Symbioses Tropicales et Méditerranéennes, Campus de Baillarguet, TA A-82/J, F-34398 Montpellier Cedex 5, France.
Depret
Géraldine
G
INRA, UMR1229 Microbiologie du Sol et de l'Environnement, BP 86510, F-21065 Dijon Cedex, France.
Bourion
Virginie
V
INRA, UR102 Génétique et Ecophysiologie des Légumineuses Protéagineuses, BP 86510, F-21065 Dijon Cedex, France.
Duc
Gérard
G
INRA, UR102 Génétique et Ecophysiologie des Légumineuses Protéagineuses, BP 86510, F-21065 Dijon Cedex, France.
D001426:Bacterial Proteins / Q000235:genetics; D016680:Genome, Bacterial; D005838:Genotype; D009584:Nitrogen / Q000378:metabolism; D009586:Nitrogen Fixation / Q000502:physiology; D018532:Pisum sativum / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology*; D018520:Plant Shoots / Q000254:growth & development* / Q000378:metabolism; D016961:Rhizobium leguminosarum / Q000235:genetics*; D053204:Root Nodules, Plant / Q000254:growth & development*; D013559:Symbiosis / Q000235:genetics* / Q000502:physiology