Effect of powdery mildew on interleaf microbial communities and leaf antioxidant enzyme systems

Chinese peony(Paeonia lactiflora Pall.)is both medicinally and aesthetically beneficial.Powdery mildew is a common fungal disease that seriously jeopardizes the value of numerous species,including peonies as a crop.In order to provide a basis for the prevention and treatment of peony powdery mildew,we examined the microbial diversity,the malondialdehyde(MDA)concentrations and antioxidant enzyme activities of peony leaves infected with three levels of powdery mildew to determine any modifications to the leaf's antioxidant enzyme systems and microbial community structure following the onset of disease.The results show that the MDA content rose as the degree of infection became worse.Antioxidant enzyme activity rose and then declined.Following the initiation of powdery mildew,fungal community diversity decreased,whereas there was not any appreciable change in bacterial communities according to microbial diversity sequencing.The relative abundance of more than half of fungal species decreased,with the bacterial genera displaying both abundant and diminished communities with less pronounced alterations in their community structure after the disease spread.Significant different taxa that were critical to the organization of each microbiome were found.Correlation analysis showed that the relative abundance of powdery mildew pathogenic fungal genus Erysiphe was correlated with those of 11 fungal genera and one bacterial genus.Among them,Aureobasidium,Neosetophoma and Sclerostagonospora showed significant positive correlations with Erysiphe and MDA.