Hypothesis 1. Phages have played a role in the evolution of Xylella through horizontal transfer and by serving as sites for largegenomic rearrangements. Our hypothesis is that an understanding of Xylella phage biology will lead the development of alternative control measures for plant disease.Objectives 1a-d: The second long-term goal of our laboratory is to develop an understanding of Xylella phage biology, which will lead to development of phage biocontrol systems. Specifically, we intend to: a) Establish a library of virulent Xylellaphages; b) Morphologically and genetically characterize phages of Xylella to determine lifestyle; c) Determine phage receptor;and d) Evaluate cocktails of virulent phages for use as agents to control or prevent plant disease caused by Xylella.Hypothesis 2. Most Bcc clinical isolates are resistant to all currently available antibiotics, rendering effective treatment nearlyimpossible. Clearly, there is a substantial need to develop new therapies. Thus, it seems prudent that phages, which are natural predators of bacteria, should be evaluated as an alternative or a complement to conventional antimicrobial treatment. Our hypothesis is that virulent phage and phage components offer an alternative and/or complement to antibiotic treatment for Burkholderia infections in humans and disease in plants.Objectives 2 a-e: It is the goal of our laboratory to develop strategies for phage therapy of infections or diseases caused by Burkholderia species. Specifically, we intend to: a) Establish a library of virulent Burkholderia phages; b) Establish a library of tailocins active against Burkholderia; c) Morphologically and genetically characterize phages and tailocins active against Burkholderia; and d) Determine phage receptor; and e) Evaluate cocktails of virulent phage and/or tailocins for use as agents for control of Burkholderia.