Host-specific competitiveness to form nodules in Rhizobium leguminosarum symbiovar viciae

Boivin Stéphane, Ait Lahmidi Nassima, Sherlock David, Bonhomme Maxime, Dijon Doriane, Heulin-Gotty Karine, Le Quéré Antoine, Pervent Marjorie, Tauzin Marc, Carlsson Georg, Jensen Erik Steen, Journet Etienne-Pascal, Lopez-Bellido Raphael, Seidenglanz Marek, Marinkovic Jelena, Colella Stefano, Brunel Brigitte, Young Peter, Lepetit Marc. 2020. Host-specific competitiveness to form nodules in Rhizobium leguminosarum symbiovar viciae. New Phytologist, 226 (2), n.spéc. Introduction to a Virtual Issue: Current research frontiers in plant epigenetics : 555-568.

https://doi.org/10.1111/nph.16392

Article de revue ; Article de recherche ; Article de revue à facteur d'impact

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Quartile : Outlier, Sujet : PLANT SCIENCES

Résumé : Fabeae legumes such as pea and faba bean form symbiotic nodules with a large diversity of soil Rhizobium leguminosarum symbiovar viciae (Rlv) bacteria. However, bacteria competitive to form root nodules (CFN) are generally not the most efficient to fix dinitrogen, resulting in a decrease in legume crop yields. Here, we investigate differential selection by host plants on the diversity of Rlv. A large collection of Rlv was collected by nodule trapping with pea and faba bean from soils at five European sites. Representative genomes were sequenced. In parallel, diversity and abundance of Rlv were estimated directly in these soils using metabarcoding. The CFN of isolates was measured with both legume hosts. Pea/faba bean CFN were associated to Rlv genomic regions. Variations of bacterial pea and/or faba bean CFN explained the differential abundance of Rlv genotypes in pea and faba bean nodules. No evidence was found for genetic association between CFN and variations in the core genome, but variations in specific regions of the nod locus, as well as in other plasmid loci, were associated with differences in CFN. These findings shed light on the genetic control of CFN in Rlv and emphasise the importance of host plants in controlling Rhizobium diversity.

Mots-clés Agrovoc : bactérie fixatrice de l'azote, Rhizobium, Rhizobium leguminosarum, Vicia faba, phylogénie, Fixation de l'azote, nodosité racinaire, variation génétique, formation de nodosités, Bacteria, génome, légumineuse, haricot commun, Phaseolus vulgaris, symbiose