Yeast community associated with winter wheat leaves and its sensitivity to fungicides

Microbial communities inhabiting the plant phyllosphere play an important role in plant health, yet their responses to agricultural chemicals remain understudied. Understanding the effect of fungicides is crucial for developing sustainable disease management strategies that preserve beneficial microbial diversity alongside effective pathogen control. This study aimed to characterise the yeast community associated with winter wheat leaves and to assess its sensitivity to fungicides used in conventional agriculture. A total of 34 yeast species were identified from 454 isolates, with 98% belonging to the phylum Basidiomycota. Sporobolomyces roseus was the dominant species, while Vishniacozyma spp. and Rhodotorula babjevae were also frequent. During the vegetation period, the abundance of three species exhibited temporal variation. Fungicide sensitivity profiling revealed that non-target yeasts were more sensitive than Zymoseptoria tritici, the pathogen responsible for septoria tritici blotch, to commonly applied fungicides such as mefentrifluconazole, prothioconazole-desthio, pyraclostrobin, and azoxystrobin. In contrast, fenpicoxamid exhibited the lowest off-target effect while remaining highly active against Z. tritici. These findings highlight the ecological complexity of the wheat phyllosphere and the potential unintended consequences of fungicide use.