Phylogenomic analysis supports a recent change in nitrate assimilation in the White-nose Syndrome pathogen, Pseudogymnoascus destructans

Cave environments are generally nutrient-poor, but can contain patches of limiting nutrients such as nitrogen in association with bats. Pseudogymnoascus destructans, the causative agent of White-nose Syndrome in bats, is thought to have recently emerged from cave soil saprotrophs. To determine whether changes in nitrate assimilation from a nutrient-limited to nitrate-rich environment could help explain the emergence of P. destructans as a pathogen, we analyzed the evolution of nitrate assimilation clusters in members of the genus. By screening the genomes of 21 members of the Pseudogymnoascus, we identified a very recent duplication of the high affinity nitrate transporter (NRT2) in P. destructans. Analyses of gene phylogeny, secondary structure, and evolutionary rates suggest the NRT2 paralog is functionally divergent, providing P. destructans a higher capacity for nitrate uptake. Such genomic changes may enhance the growth of P. destructans in bat-associated cave environments.