Isolation, characterization and biocontrol efficacy of bacteriophages specific for different X. fastidiosa subspecies and STs

Subproject TED2021-130110B-C42will be led by IVIA

This subproject will focus on the search, characterization and selection of bacteriophages against X. fastidiosa, with special emphasis on those with lytic activity against strains of the subspecies multiplex, the predominant one in the various European outbreaks. Bacteriophages are highly specific, naturally present in the environment, and their presence is linked to that of the host, which makes them a natural and environmentally friendly mitigation strategy.

The overall objective is to have an effective control tool based on the use of bacteriophages, exploiting the results from previous projects in which phages effective against X. fastidiosa subsp. fastidiosa have been selected. We will also isolate and select new phages effective against strains of different X. fastidiosa subspecies and STs, with special emphasis on subsp. multiplex. For this purpose, new sources or reservoirs will be explored and strategies of directed evolution for phage will be performed. Finally, we will assess the efficacy of those phages when applied individually or as cocktails to suppress disease development.

In order to have a collection of phages that could be a useful tool combined with other strategies in an integrated management plan for X. fastidiosa diseases, three specific tasks are proposed:

1 – The search, isolation and characterization of phages from different reservoirs, including the determination of their host range, the study of their morphology and their genome.

2 – The directed evolution to achieve an optimization of the selected phages, in order to circumvent the occurrence of resistance and modulate the host range.

3 – The evaluation of their lytic activity in vivo using model plants. The expected results would contribute to have a biological control tool that would allow a more eco sustainable plant production, thanks to the reduction of the effect of X. fastidiosa diseases, which would reduce the use of chemical compounds, which are not effective and have a high economic and environmental cost.