Calonectria pseudonaviculata and C. henricotiae are two closely related fungal species responsiblefor boxwood blight disease of ornamental shrubs (Buxus spp.) in the U.S. and Europe.A previous study has shown isolates of the latter species, which is restricted to Europe, tobe less sensitive to tetraconazole, an azole fungicide. In this study, we have analyzed theCYP51 paralogs for polymorphism in 26 genomes, representing geographically disparatepopulations of C. pseudonaviculata (n¼19) and C. henricotiae (n¼7), from the U.S., Europe,Asia, and New Zealand. The presence of a CYP51A pseudogene and lack of a functionalCYP51A paralog in all C. pseudonaviculata genomes examined is a novel discovery for fungiand could have implications for the evolution of resistance to antifungal chemicals.

Calonectria pseudonaviculata and C. henricotiae are two closely related fungal species responsiblefor boxwood blight disease of ornamental shrubs (Buxus spp.) in the U.S. and Europe.A previous study has shown isolates of the latter species, which is restricted to Europe, tobe less sensitive to tetraconazole, an azole fungicide. In this study, we have analyzed theCYP51 paralogs for polymorphism in 26 genomes, representing geographically disparatepopulations of C. pseudonaviculata (n¼19) and C. henricotiae (n¼7), from the U.S., Europe,Asia, and New Zealand. The presence of a CYP51A pseudogene and lack of a functionalCYP51A paralog in all C. pseudonaviculata genomes examined is a novel discovery for fungiand could have implications for the evolution of resistance to antifungal chemicals.