Genomic Complexities in the Legume-Rhizobial Symbiosis

Abstract

As two different organisms interact in a symbiotic nature and evolve over time, underlying genetic changes begin to reflect this. These changes are reflected as genomic complexities within the genome of each species, and further segregates within individuals of those species. In my work, I have studied three facets of understanding the genomic complexities of symbiotic organisms. i) I developed the omics database generator (ODG) which allows characterization of multiple genomes simultaneously while connecting new data to existing, published research. As more genomes are sequenced the ability to compare these genomes to existing datasets will require more advanced genomic tools. ii) I have studied copy-number variation and presence-absence variation in M. truncatula to identify genes involved in the legume-rhizobial symbiosis, resulting in the identification of a likely causative locus and exploring the copy-number variation within the association mapping population using a high-throughput method using second-generation sequencing data. iii) I have further investigated the dynamics of repeats in a population of Ensifer meliloti to understand how the genomes are being shaped and evolving, as well as the characteristics of repeats unique to the E. meliloti lineage and those shared with other species, and understanding the relationships between these repeats and the underlying genomes. My work has expanded on methods of examining genomic complexities underlying complex, quantitative host-symbiont interactions at a genomic scale.