A highly contiguous genome assembly reveals sources of genomic novelty in the symbiotic fungus Rhizophagus irregularis

The root systems of most plant species are aided by the soil-foraging capacities of symbiotic arbuscular mycorrhizal fungi from the Glomeromycotina subphylum. In this paper, the authors assemble the genome of Rhizophagus irregularis, the model species for studying arbuscular mycorrhizal fungi in the laboratory. Understanding the biology and genetics of any organism relies on the presence of a high-quality ‘reference genome’. Conducting this chromosome-scale view of the genome of an arbuscular mycorrhizal fungus genome, the authors reveal previously unexplored sources of genomic novelty in an organism evolving under an obligate symbiotic life cycle.