KILL XYL project.

Our project KILL XYL is to find a cure for the disease caused by the plant pathogen Xylella fastidiosa. This disease currently causes the loss of thousands of acres of European crops and currently there is no cure for it.

At Aix-Marseille University we thought about developing a solution that multiple aspects. First, we wanted to improve detection of the disease. To do this we use an NDVI camera that will help us to see if the plant is stressed or not. If the plant is infected by Xylella fastidiosa, it suffers from a hydric stress that stops the photosynthesis.

Secondly, we want to get rid of the bacteria. Phages are natural predators of bacteria. They can also be used to transfer DNA into bacteria. Phages have the additional advantages of being strain specific and in some cases customizable. As we wanted an eco-friendly treatment, to facilitate obtaining marketing authorizations, we decided to create phage-like particles (PLPs), that aren't able to spread. So we set out to construct phage specific to X. fastidiosa, capable of injecting toxic genes into the bacteria.

The main cause of plant mortality is hydric stress induced by the accumulation of biofilm in xylem vessels. To disrupt the biofilm we thought of two different approaches. The first is to stop the bacteria from producing extra-cellular polysaccharides, we achieve this by quenching bacterial quorum sensing using a short chain fatty acid called: 2-cis-decenoic acid. The second approach is to destroy the exo-polysaccharides using an enzyme obtained from a bacteriophage to hydrolyse the polysaccharides.

Hence, KILL XYL simply detects, disrupts and kills Xylella fastidiosa.