A 971-bp insertion in the rns gene is associated with mitochondrial hypovirulence in a strain of Cryphonectria parasitica isolated from nature

► An insert in the rns gene of strain KFC9 was linked to hypovirulence. ► The characterization of the InC9 element showed that it is a group II intron. ► The InC9 element possibly induces hypovirulence as it is defective in splicing.