Identified ~50% of Pathogenicity Genes for the Pathogen that Causes Fire Blight in Apple and Pear
Fire blight is a disease affecting a variety of rosaceous plants and impacts apple and pear production worldwide. Though it is sporadic, this disease, which is caused by the bacterium Erwinia amylovora, can be devastating. Although this disease has been studied for over 200 years, the mechanisms by which E. amylovora causes fire blight disease are incompletely understood. The McNellis lab set out to identify all of the genes of E. amylovora that are required for the fire blight disease process. From the more than 10,000 random mutants screened, about 200 were identified which had lost pathogenicity. This resulted in the identification of numerous new genes involved in the fire blight disease process, including genes encoding proteins involved in signaling, gene expression, membrane surface functions, and extracellular activities. This work has identified approximately half of all the E. amylovora genes required for fire blight disease to occur. This has provided a more complete picture of the mechanisms used by E. amylovora to cause disease in apple and pear, which did not exist before.