Wilsoniana sp. associated with white blister rust of Amaranthus palmeri in Mexico

Morphological and phylogenetic analyses were conducted with two white blister rust specimens from Amaranthus palmeri collected in Sinaloa, Mexico. Secondary sporangia were similar to those of W. bliti and W. amaranthi. The coarsely reticulate epispore of the oospores corresponded to W. amaranthi, although they were smaller than those reported in the same species on A. dubius. The diameter of the oospores was similar to that in W. bliti from A. blitum, whereas the pattern of ornamentation did not correspond to this species. The phylogenetic analysis confirms that both specimens belong to Wilsoniana but do not correspond to any accepted species within the genus, and they have therefore been designated as Wilsoniana sp. Future research lines should focus on the description and taxonomic position of species in the genus Wilsoniana.