Effect of powdery mildew on the composition of phyllosphere microbial community of Euonymus japonicus

Powdery mildew is a fungal disease that affects a wide range of plants. To assess its impact on the phyllosphere microbiome of Euonymus japonicus , we employed high-throughput sequencing platform to analyze the variation in 16S rRNA, ITS and nifH gene profiles between infected and non-infected microbiomes. The results revealed that healthy leaves harbored relatively higher total bacterial diversity (Shannon index) in healthy leaves, whereas infected leaves showed increased diversity of fungi and the nitrogen-fixing bacterial subgroup. However, the abundance of several microbial genera including Pantoea, Pseudomonas, Alternaria, Filobasidium , Cladosporium and Skermanella was significantly increased on leaves infected with powdery mildew. These findings suggest the possible existence of specific inter-species relationships (such as competition, commensalism, or mutualism) between the microbiota and the powdery mildew pathogen. This study revealed the shifts in the phyllosphere microbial community of Euonymus japonicus following powdery mildew infection, and identified multiple microbial taxa (such as Pseudomonas and others) that are significantly associated with the pathogen. These taxa could serve as potential antagonistic or biocontrol agent resources for subsequent functional validation and development.