Simplicillium lamellicola (Smith) Zare & Gams, a novel hyperparasitic fungus infecting Puccinia striiformis f. sp. tritici.

Wheat stripe (or yellow) rust, caused by the Basidiomycota fungus Puccinia striiformis West. f. sp. tritici Eriks. & Henn. (Pst), is one of the most destructive wheat diseases globally. Frequent outbreaks of this disease often lead to substantial crop yield losses. Currently, the primary strategies for controlling wheat stripe rust rely on the cultivation of resistant cultivars and the application of fungicides. However, fungicide use is associated with a range of adverse effects, such as environmental pollution and disruption of ecological balance. As a result, the development of promising biocontrol agents or microbial pesticides based on parasitic microbes has emerged as a more sustainable and effective approach to managing this disease. In the present study, we used a combination of morphological observation and multigenes based-molecular phylogenetic analyses to identified a hyperparasite, isolated from Pst urediospores collected from infected wheat leaves, as Simplicillium lamellicola (Smith) Zare & Gams. Further experimental results demonstrated that inoculating Pst-infected wheat leaves with S. lamellicola inhibited the production of Pst urediospores and ultimately caused the death of rust spores. These findings suggest that S. lamellicola holds great potential for development as a bio-control agent against wheat stripe rust, offering an eco-friendly alternative to conventional fungicides.