Symbiosis genes show a unique pattern of introgression and selection within a Rhizobium leguminosarum species complex.

ABSTRACT: Rhizobia supply legumes with fixed nitrogen using a set of symbiosis genes. These can cross rhizobium species boundaries, but it is unclear how many other genes show similar mobility. Here, we investigate inter-species introgression using de novo assembly of 196 Rhizobium leguminosarum sv. trifolii genomes. The 196 strains constituted a five-species complex, and we calculated introgression scores based on gene-tree traversal to identify 171 genes that frequently cross species boundaries. Rather than relying on the gene order of a single reference strain, we clustered the introgressing genes into four blocks based on population structure-corrected linkage disequilibrium patterns. The two largest blocks comprised 125 genes and included the symbiosis genes, a smaller bloc

SUBMITTER: Cavassim MIA 

PROVIDER: S-EPMC7276703 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature