Powdery mildew-induced changes in phyllosphere microbial community dynamics of cucumber

Abstract

Abstract As an important habitat for microorganisms, the phyllosphere has an important impact on plant health and growth. The changes of the phyllosphere microorganisms are closely related to the occurrence of leaf diseases. However, little is known about how the microbial community changes in the phyllosphere under the infection of pathogen. Here, we analyzed the microbial communities in the phyllosphere at different disease levels (L1 ≤ 10%, 30% ≤ L2 < 50%, and L3 ≥ 50%) to explore the dynamic changes of the phyllosphere microorganisms. The analysis showed that bacterial microbial community diversity increased with disease severity and fungal diversity gradually decreased. There were no significant differences in the community structure and composition of phyllosphere microorganisms at different levels of incidence, the relative abundance of species changed significantly. The relative abundance of rosenbergiella, rickettsia and cladosporium was negatively correlated with the severity of the disease, while bacillus, pantoea, kocuria and podosphaera were positively correlated with the severity of the disease. Co-occurrence network showed that both fungal and bacterial communities L1 have relatively stable and complex ecological networks. The bacterial network tends to be unstable with the increase in disease degree, and the fungal network gradually stabilizes. These studies showed that the severity of the disease will have a certain impact on the phyllosphere microbial community, which provides a new reference for cucumber powdery mildew control from a microbial perspective.