Morphological and Molecular Identification of New Puccinia Species from Qinghai, China

Rust fungi of the genus Puccinia are important plant pathogens responsible for substantial economic losses in agriculture and forestry. During field surveys conducted in Qinghai Province, China, a novel rust species, Puccinia ligulari-przewalskii, was discovered parasitizing Ligularia przewalskii. Morphological characteristics of its teliospores were examined using light microscopy (LM) and scanning electron microscopy (SEM). Molecular phylogenetic analysis based on the concatenated internal transcribed spacer (ITS) and large subunit (LSU) ribosomal DNA sequences supported its taxonomic distinction as a new species within the genus Puccinia. Phylogenetic reconstructions inferred from maximum likelihood and Bayesian inference showed that the new species forms a distinct, well-supported lineage, clustering as sister to a clade comprising Puccinia argentata and Puccinia komarovii. P. ligulari-przewalskii is characterized by two-celled, spindle-shaped teliospores exhibiting sparse verrucose ornamentation on the spore wall. Only the telial stage was observed across multi-year surveys, and the complete life cycle remains to be determined. This study contributes to the taxonomic knowledge of rust fungi in China and underscores the ecological and phytopathological significance of rust fungi in the Qinghai–Tibet Plateau region.