STABILITY AND INHIBITORY CAPACITY OF BACTERIOPHAGE ФRSP, A POTENTIAL AGENT FOR THE BIOCONTROL OF Ralstonia solanacearum

Abstract

Marchitez bacteriana del tomate causada por Ralstonia solanacearum is a recurring problem in the state of Morelos and other parts of Mexico and the world. Current methods for the control of this bacterial phytopathogen are based on the use of antibiotics that promote the selection of resistant bacteria, and on agrochemicals that are toxic to humans, plants and the environment in general. These control methods degrade the quality of soils by eliminating much of the normal microbiota due to their broad spectrum of action. This situation highlights the need to develop alternative control methods that are aligned with the sustainable development of agriculture. The strict lytic bacteriophages offer an alternative of control due to their high specificity, low toxicity and capacity of auto-amplification. In this paper, the isolation, stability and inhibitory capacity of bacteriophage ФRSP, infective for R. solanacearum are reported. This bacteriophage belongs to the family Mioviridae and generates lysis plates of approximately 0.5 cm in diameter after 24 h of incubation, which continue to increase their size over time. This bacteriophage has the ability to clarify liquid cultures of R. solanacearum at very low multiplicities of infection and is stable in the nutrient solution used for the cultivation of hydroponic tomato, in a pH range from 4 to 11; however, it is unstable in ultrapure water. Results show that the bacteriophage ФRSP presents characteristics that point it as a good candidate to be used as a biocontrol agent against bacterial wilt caused by R. solanacearum.