A team of researchers from the MolMicro of Bacterial Pathogens lab at UCIBIO - NOVA FCT has developed a new laboratory culture medium that enables the fast and effective in vitro growth of Xylella fastidiosa. This advancement, supported by the Portuguese Yeast Culture Collection (PYCC) infrastructure, promises to revolutionize research on this pathogen, which is one of the greatest threats to agriculture in Europe and Portugal.
Xylella fastidiosa is a bacterium that colonizes plant vessels (xylem), blocking the transport of water and nutrients. It is responsible for devastating diseases such as Olive Quick Decline Syndrome, Pierce’s Disease in grapevines, and Almond Leaf Scorch. Until now, studying this bacterium was particularly challenging due to its slow growth in laboratory settings, which can take between 7 to 30 days under conventional conditions. This limitation has hindered experimental progress and the development of effective control strategies.
From weeks to days: The XFG system
The study, led by Carla Pinheiro, researcher at the MolMicro of Bacterial Pathogens Lab, and developed by the PhD student Eduardo Costa-Camilo, introduces the XFG (Xylella Fast Growth) medium. This innovative system allows for robust in vitro growth, with visible colony formation in just three days in both liquid and solid media.
“With this system, we can observe bacterial growth and the formation of visible colonies in a short period, drastically reducing experimental time,” explain the authors. This acceleration is particularly relevant for high-throughput screening, enabling the simultaneous analysis of thousands of compounds or genetic conditions much more rapidly than previously possible.
Compatibility with antibiotic testing
To demonstrate the effectiveness of the new medium, the research team conducted antimicrobial susceptibility tests. The results were consistent with traditional methods but achieved in a significantly shorter period. Xylella fastidiosa showed sensitivity to antibiotics such as rifampicin and tetracycline, reinforcing the reliability and applicability of the XFG system for laboratory studies.
Economic and Agricultural Impact
First detected in Europe in 2013 and in Portugal in 2019, Xylella fastidiosa is considered a priority quarantine pathogen due to its spread via insect vectors and its impact on vital crops like olive trees, almond trees, and vineyards.
“This advancement overcomes one of the main limitations in the study of Xylella fastidiosa, opening the way for faster physiological analysis and the development of control strategies,” conclude the UCIBIO researchers who developed the study: Eduardo Costa-Camilo, Tomás Martins, Cláudia Carvalho, Rita G. Sobral, and Carla Pinheiro.
The new XFG method is now available to the scientific community, offering a vital tool to accelerate the discovery of solutions to mitigate the impact of this "plague" threatening the agricultural and economic heritage of the Mediterranean region.
Original Article:
Redefining Xylella fastidiosa cultivation: An improved growth system for faster physiological and antimicrobial studies
Eduardo Costa-Camilo, Tomás Martins, Cláudia Carvalho, Rita G. Sobral, Carla Pinheiro Journal of Microbiological Methods, 2024