Enzymatic Quorum Quenching Suppresses Bacterial Plant Diseases and Alters the Phyllosphere Microbiome

Plant diseases caused by bacterial infections result in significant crop losses and hundreds of millions of dollars in damages annually in the United States alone, adding stress to an already strained global food supply. Many plant pathogenic bacteria use N-acyl homoserine lactone (AHL)-mediated quorum sensing (QS) systems to control biofilm formation and virulence gene expression. Strategies that interfere with bacterial quorum sensing systems employ enzymes to degrade or transform AHLs. We previously isolated and engineered a highly stable AHL-degrading lactonase, SsoPox, that enables evaluation of enzymatic plant treatments for bacterial disease suppression under diverse environmental conditions. In a proof-of-concept work, we show that a formulated lactonase spray successfully reduces symptoms of Goss's Wilt, a leaf blight disease caused by Clavibacter nebraskensis. Lactonase treatment mitigated plant symptoms, and qPCR experiments revealed a small, yet significant reduction of pathogen abundance on plant leaves following enzymatic treatment. Sequence analysis of phyllosphere microbiota showed a significant alteration of the composition and structure of the leaf microbial community upon infection. However, lactonase treatment largely reduced this shift, resulting in a surface leaf community close to uninfected controls. This study demonstrates the critical role of microbial signaling in complex leaf communities and highlights the potential of quorum quenching lactonases to control Goss's Wilt disease.These sequencing data are from the leaf plyllosphere microbiome of the linked paper.