Disentangling Co-Occurring Pathogens: Lack of Significant Interaction Between Agrobacterium tumefaciens and Ganoderma...

Although plant diseases often involve coinfections of multiple pathogens, there are few studies that focus on understanding plant host-multipathogen interactions. To understand the complexities of cross-taxa coinfections, we investigated the interactions between an almond tree, wood-decay pathogen, Ganoderma adspersum, and a bacterial pathogen, Agrobacterium tumefaciens. The high coincidence of the fungal and bacterial pathogens in almond orchards suggests mutualistic effects in pathogenesis. However, coinoculation assays revealed that the pathogens do not significantly interact directly with each other or promote increased initial disease development. The rise of multipathogen diseases in almonds likely results from the adoption of management practices that have created a system capable of sustaining multiple pathogens.