Molecular and morphoanatomical characterization of Urocystis heteropogonis sp. nov.: a novel smut fungus infecting Heteropogon contortus.

Background: A new species of smut fungus, Urocystis heteropogonis, was discovered infecting Heteropogon contortus in Shawar Valley, Swat district, Khyber Pakhtunkhwa, Pakistan. The study aimed to characterize this fungus based on its morpho-anatomical and molecular features and clarify its phylogenetic position within the genus Urocystis.

Results: Urocystis heteropogonis was identified as a novel species, distinct from other Urocystis species. Morphologically, it is characterized by larger spore balls (14-69 × 11-45 μm) and central spores that are 14-28 × 11-20 μm in size, with each spore containing1-8 central spores. The spore walls measure 0.9-2.5 μm in thickness and the species differs in infection patterns compared to other Urocystis species. Phylogenetic analysis based on the ITS and LSU regions of nuclear ribosomal DNA (nrDNA) further confirmed the novelty of the species, placing it within a distinct clade alongside U. agropyri, U. occulta, U. piptatheri, and U. tritici.

Conclusions: The discovery of Urocystis heteropogonis adds to the diversity of smut fungi infecting grasses and highlights the need for further research into its ecological and agricultural implications. Future studies should focus on the disease's spread, management, and potential impact on host populations.