Saint Pierre, Réunion
14/02/2011 - Snippets
CIRAD has developed a detection test for all the strains of the bacterium Xanthomonas axonopodis pv. allii in onion. The test will make it possible to control seed health at the time of sale.
The bacterium Xanthomonas axonopodis pv. allii affects Alliums, such as onion, garlic, leek, chive and shallot, causing lesions on the aerial tissues of the plant, which then wilts. The bulbs shrink, resulting on yields losses of anything between 10 and 50%. Research aimed at developing a test to detect the bacterium in seeds recently bore fruit.
The test is capable of detecting all the strains of the bacterium. It is around three times more sensitive than conventional methods, with a detection threshold of one contaminated seed in 30 000. It is also faster, as it comprises fewer stages: the bacterium no longer has to be isolated, and the DNA extracted from a seed macerate is studied directly by a double PCR.
The disease is found on almost every continent, particularly in the southwestern Indian Ocean, on Réunion and Mauritius. The test will serve to control the health of imported and locally produced seeds. The method is to be proposed as a European reference method to the European and Mediterranean Plant Protection Organization (EPPO), which added the bacterium to its quarantine lists in 2009.
Robène-Soustrade I., Legrand D., Gagnevin L., Chiroleu F., Laurent A., Pruvost O., 2010. A
multiplex nested PCR for detection of Xanthomonas axonopodis pv. allii from onion seeds. Applied
and environmental microbiology, 76: 2697-2703.
Patent registered in France on 21 October 2009 and PCT extension registered on 21 October 2010.