Taxonomy, Host Associations, and Life Cycles of Four Rust Fungi Associated with Prunus spp. in Korea

Rust fungi associated with Prunus spp. in Korea have been reported under different genera, yet their taxonomy, host associations, and life cycles have remained insufficiently clarified. In this study, rust specimens collected from Prunus species and their putative alternate hosts were examined using morphological observations and molecular phylogenetic analyses based on internal transcribed spacer (ITS) and large subunit (LSU) rDNA sequences. Four species belonging to three genera were identified: Blastospora makinoi, Blastospora radiata, Leucotelium semiaquilegiae, and Tranzschelia discolor. Blastospora radiata and L. semiaquilegiae are newly recorded in Korea. In addition, Prunus salicina and Semiaquilegia adoxoides are reported for the first time in Korea as hosts of rust fungi. Field investigations combined with sequence data clarified the heteroecious life cycles of Blastospora and Leucotelium species in Korea, confirming host alternation between Prunus spp. and alternate hosts including Se. adoxoides and Smilax spp. Historical records of rust fungi on Prunus in South Korea were taxonomically reassessed in light of these results. The congruence between molecular phylogenies and morphological characteristics provides an updated taxonomic framework for rust fungi associated with economically important Prunus species.