Phylogenomic characterization of peanut (Arachis hypogaea) microsymbionts obtained from Argentina and Senegal

ABDELLATIF GUEDDOU; GONZALO TORRES TEJERIZO; DIARIATOU NIANG; DARIUS NZEPANG; ARLETTE ZAIYA; DIEGANE DIOUF; DANIEL FONCEKA; DJAMEL GULLY; VALÉRIE HOCHER; FERNANDO IBAÑEZ; KRSYLANNE MORRIS; STEPHEN SIMPSON; SOFÍA STEFANINI; SERGIO SVISTOONOFF; LOUIS TISA; SALIOU FALL

Dakar

Congreso; 19ème CONGRES DE L?ASSOCIATION AFRICAINE POUR LA FIXATION BIOLOGIQUE DE L?AZOTE; 2022

INTRODUCTIONCultivated peanut (Arachis hypogaea L.) was domesticated in South America but is now cultivated worldwide and constitutes an important oil and food legume, with an annual production of 50 million tons (USDA, 2022). In addition to its economic importance, peanut contributes to a balanced nutritional state in soils due to its ability to establish a nitrogen-fixing symbiotic association with rhizobia. In order to deepen the knowledge of the genetic diversity of microsymbionts, this work focus on the phylogenomic characterization of bradyrhizobial isolates obtained from nodules of peanut plants grown either in Argentina, its zone of origin, or in Senegal, where peanut was introduced in the XVIth century. METHODOLOGYWhole genome sequence of 12 bradyrhizobial isolates from Argentina (2) and Senegal (10) was obtained through nanopore and Illumina systems. Genome sequence analysis was performed using TYGS and EDGAR.RESULTSThe hybrid strategy used for sequencing allowed to obtained, in most of the cases, closed replicons. The core genome and symbiotic (nodC) phylogenetic analysis, together with in silico DNA-DNA hybridization and average nucleotide identity, depicts that the strains cluster into four different phylogenomic groups: two groups with strains from Senegal and two groups containing the isolates from Argentina. CONCLUSIONS AND PERSPECTIVESTaken together, the results obtained in this work allowed to propose three new species within the collection of isolates. A better knowledge of the genomic traits of peanut symbionts could lead to a deeper comprehension of the molecular basis of the symbiosis and to optimize the selection of rhizobial inoculants.