Effects of Mixed Fungicides on Occurrence of Grapevine Powdery Mildew and Microbial Diversity in Grapevine Phyllosphere
In order to clarify the effects of common fungicides and biocontrol agents on the occurrence of grapevine powdery mildew and grapevine foliar microbial diversity,and further predict the function of foliar microorganisms,random sampling method was used to investigate grapevine powdery mildew in the field,the differences of microbial community diversity between fungicide and biocontrol treatment were analyzed by Illumina high-throughput sequencing technology combined with bioinformatics,and the microbial function was predicted by PICRUSt2.The results showed that the application of mixed bacterial agents could significantly reduce the incidence of powdery mildew.Chao1 index and Shannon index of grapevine leaf bacterial community decreased by 50.78%and 48.57%,respectively;Chao1 index of foliar fungal community decreased by 42.80%,and Shannon index increased by 0.07.At the phylum level,the dominant bacteria phyla of pesticide treatment were Bacillota and Actinomycetota,and the dominant fungi phyla were Ascomycota and Basidiomycota.At the genus level,after pesticide treatment,the bacteria with significantly increased relative abundance were Bacillus,and the fungi with significantly increased abundance were Erysiphe and Aspergillus.In the prediction of grapevine leaf microbial community function,489 MetaCyc pathways were evaluated.Based on the screening of P<0.05 and Fold Change(FC)>3,and 49 related pathways were obtained,of which two were significantly up-regulated and 47 were significantly down regulated,which were mainly related to the functions of grapevine nuclear acid metabolism,photorespiration,chlorophyll and vitamin synthesis.