Isolation, Identification and Hyperparasitism of a Novel Cladosporium cladosporioides Isolate Hyperparasitic to Puccinia striiformis f. sp. tritici, the Wheat Stripe Rust Pathogen

SIMPLE SUMMARY: Obligate biotrophic pathogen Puccinia striiformis f. sp. tritici (Pst) is a major threat to wheat production. Parasites of Pst can be used to develop biological agents for environmentally friendly control of this fungal disease. Here, we report a hyperparasitic fungus isolated from taupe-colored uredinia of Pst and identified as Cladosporium cladosporioides through molecular and morphological characterizations. The hyperparasitic isolate was able to reduce the production and viability of Pst. Therefore, Cladosporium cladosporioides may have potential in biological control of stripe rust on wheat. ABSTRACT: Wheat rust outbreaks have caused significantly economic losses all over the world. Puccinia striiformis f. sp. tritici (Pst) is an obligate biotrophic fungus causing stripe rust on wheat. Application of fungicides may cause environmental problems. The effects of hyperparasites on plant pathogens are the basis for biological control of plant pathogenic fungi and parasites of Pst have great value in biological agents development. Here, we report the isolation and characterization of isolate of Cladosporium cladosporioides from Pst based on morphological characterization and analysis of molecular markers. The hyperparasitic isolate was isolated from taupe-colored uredinia of Pst. Upon artificial inoculation, the hyperparasitic isolate was able to reduce the production and germination rate of Pst urediospores, and Pst uredinia changed color from yellow to taupe. Scanning electron microscopy demonstrated that the strain could efficiently colonize Pst urediospores. Therefore, the isolate has the potential to be developed into a biological control agent for managing wheat stripe rust.