Responses of phyllosphere microbiota and plant health to application of Bordeaux Mixture

Abstract

Abstract To investigate the ecological effects of fungicides on tobacco target spot, a field experiment was conducted to investigate the control efficacy at 3 and 9 days after spraying 80% Bordeaux Mixture and the effect on the phyllosphere microbial communities of tobacco leaves at different persistence periods of the fungicide through high-throughput sequencing. The results showed that Bordeaux Mixture had remarkable control effects against tobacco target spot at the beginning, but showed powerless control effects at the late stage of application. Bordeaux Mixture had significant effects on the phyllosphere microbial communities of tobacco leaves. Compared with the diseased group, the healthy group had a richer species diversity in fungal community structure before application. After application, the diversity of microbial community on diseased leaves increased over time and the abundance of the pathogen Thanatephorus decreased (79.35%) significantly. And the function prediction showed that the relative abundance of “pathotroph” fungal communities decreased after Bordeaux Mixture application. Tobacco target spot had changed the microbial community structure with lower diversity and higher relative abundance of pathogen, after treatment of Bordeaux Mixture, the diversity of community was increasing and the relative abundance of pathogen was decreasing significantly over time.