Robigalia Roundup LXXVI: Marie Skłodowska-Curie Action Fellowships open

Every year, Xylella fastidiosa edges closer to the heart of European agriculture. Classified as a quarantine pathogen by the European Union, it has already decimated millions of olive trees across southern Italy and has since been detected in Spain, France, and Portugal.

Xylella fastidiosa is a Gram-negative, xylem-limited bacterium with an exceptionally wide host range, capable of infecting olives, grapevines, almonds, citrus, and hundreds of other plant species. What makes it biologically remarkable is its infection strategy. Once inside a plant, the bacterium uses type IV pili for twitching motility, moving against the flow of xylem sap while releasing enzymes that degrade pit membranes between adjacent xylem vessels.

As bacterial populations build, a diffusible signal factor triggers a switch from a motile to an adhesive state, and the bacteria form dense biofilms that physically block water transport throughout the plant. The result is a progressive scorching and wilting of leaves, dieback of shoots, and in olives, a condition known as Olive Quick Decline Syndrome, where trees that may have stood for centuries collapse within a few seasons.

The bacterium's spread depends entirely on xylem-sap feeding insects, primarily the meadow spittlebug Philaenus spumarius in Europe. There is no latent period required: a vector can acquire the bacterium from an infected plant and transmit it to a new host immediately. This, combined with X. fastidiosa's capacity for horizontal gene transfer between strains and subspecies, makes it a pathogen that adapts quickly and spreads efficiently.

Since its first detection in Apulia, Italy in 2013, the bacterium has caused the loss of an estimated 6.5 million olive trees by 2017 alone. Modelling suggests that if X. fastidiosa were to spread fully across the EU, it could affect over 70% of the production value of olive trees older than 30 years and put nearly 300,000 jobs at risk across olive, citrus, almond, and grapevine production.

Management remains one of the hardest problems in European plant health. There are no curative treatments once a plant is infected. Current strategies focus on four approaches: removal and destruction of infected plants, deployment of resistant or tolerant cultivars, suppression of insect vectors through chemical or biological means, and strict quarantine enforcement to prevent further spread. In olive, the varieties Leccino and FS17 have shown resistance where the widely grown Ogliarola salentina and Cellina di Nardò are highly susceptible. Research into biological control of Philaenus spumarius using the predatory insect Zelus renardii has shown early promise as a sustainable management option.

This week, we meet José Ortega, Head of the Phytopathology Department at AGRAMA, whose career has been shaped by a consistent drive to bring molecular science closer to the crops that depend on it.

José holds a PhD in Biology from the University of Seville, with specialisations in phytopathology, molecular diagnostics, and pathogen control in agricultural crops. His early work took him to IFAPA and ARVENSIS AGRO, where he contributed to nationally and internationally funded R&D projects on natural compounds, biostimulants, and plant defence mechanisms.

It was here that he developed the expertise in research and field relevance that was needed for the rest of his career. He went on to author several scientific publications and present at international conferences on biological control and crop diseases.

From there, José moved into technical management at NEWBIOTECHNIC S.A., where he served as Technical Director of the Agri-food Department. He organised and managed the molecular biology laboratory, implemented quality systems, and built new business lines in molecular diagnostics, genotyping, GMO detection, and food fraud.

That experience laid the foundation for what he has built at AGRAMA. As Head of the Phytopathology Department, José created and consolidated the department. Its work centres on the diagnosis and detection of phytopathogenic organisms using molecular biology techniques, translating laboratory capability into practical frameworks for plant health decisions.

Reach out to José on LinkedIn if you are working in molecular plant diagnostics, crop disease management, or the quality frameworks that underpin applied plant pathology.

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See you next Monday!

P.S. Why Robigalia? The name originates from the Ancient Roman festival dedicated to crop protection. You can read all about the history here: