Special Session: Innovative Approaches to Control Difficult Bacterial Pathogens

39-S

Virulent bacteriophages of Xylella fastidiosa: potential biocontrol agents for Pierce’s Disease.
M. Das (1), T. S. Bhowmick (2), S. J. Ahern (2), R. F. Young (3), C. F. GONZALEZ (2)
(1) Department of Plant Pathology and Microbiology, Texas A&M University, College Station , TX, U.S.A.; (2) Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, U.S.A.; (3) Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, U.S.A.

Xylella fastidiosa is the causal agent of Pierce's Disease (PD), a major threat to the wine industry in the USA. Currently, there are no effective control measures to prevent infection or manage the disease, short of aggressive culling of infected vines, once established in a vineyard. The search for new methods to combat microbial pathogens is an ongoing process in both medicine and agriculture. Bacteriophages (phages; bacterial viruses) offer a novel strategy not previously pursued for the control of PD, because methods to isolate and propagate viable virulent phages were not available. Bacteriophages specifically target the underlying bacterial pathogen, without posing any harmful effects to humans, animals or plants. Our laboratory has isolated and characterized virulent phages for X. fastidiosa, making feasible the development of phage therapy for the treatment of PD. The therapeutic and preventative efficacy of a phage cocktail composed of virulent phages Sano, Salvo, Prado and Paz to protect grapevines (Vitis vinifera cv. Cabernet Sauvignon) against X. fastidiosa was evaluated in greenhouse experiments. The results demonstrated the efficacy of phages in both treatments. An ongoing trial will test efficacy under field conditions. Application of phages as a biocontrol agent for X. fastidiosa offers a novel biological treatment for control of PD.