The fungal community of wheat phyllosphere was affected by the co-occurrence of stripe rust and powdery mildew

Both wheat stripe rust and powdery mildew are important diseases in the world, which mainly infect the leaves and cause serious yield loss. In this study, the leaf samples of two varieties were collected from different pathogenic processes of stripe rust and powdery mildew that co-occurred in plants, and the internal transcribed spacer (ITS1) amplicon sequencing was introduced to analyse the structure and diversity of phyllosphere fungal communities. The results showed that the alpha diversity indices of the fungal communities were decreased with the pathogenic process, and the beta diversity among the different pathogenic process were significantly different as well. In addition, an Adonis analysis showed the pathogenic processes affected the structure of the fungal community, which could explain 45.6% of the variance in the community structure, on the contrary, the variety has no effect both on the community diversity and the structure. With the development of the pathogenic process, the abundance of both pathogens (Puccinia striiformis and Blumeria graminis) increased significantly, as well as for the relative abundance of some fungi (i.e., Alternaria spp., Cladosporium spp., etc.). The relative abundance of other genera (e.g., Aureobasidium, Epicoccum, etc.) increased at the early pathogenic stage, then decreased at the late pathogenic stage. Comprehensively, these fungi may have the potential to compete with pathogens for nutrients, which may be the target for the development of biological control agents.