Efficient biocontrol of the phytopathogen Ralstonia solanacearum by novel lytic bacteriophages in irrigation water, in planta and after mass production

Abstract: The phytopathogen Ralstonia solanacearum produces bacterial wilt, one of the most damaging plant diseases worldwide. A number of control methods have been applied in the field with either environmental impact and/or uncertain success, mainly due to the high pathogenic potential of the bacterium and its long-term persistence in the environment. Biological control strategies have the advantage of being able to be easily integrated in a sustainable agricultural system. In this sense, lytic bacteriophages (phages) can destroy their target specifically without impact on the ecological balance. Ralstonia solanacearum lytic phages were isolated and their biocontrol ability tested in environmental water, and in planta. Results revealed either reductions in R. solanacearum populations in water or bacterial wilt incidence in the host, with absence of symptoms in many of the plants. Phages were mass produced in bioreactors and their biocontrol ability tested in the same way with similar results, indicating a good potential of the newly isolated phages for bacterial wilt biocontrol in conditions mimicking those of natural settings.