2023/12/05 by Cadot, Valérie, Bonnefoy, Michel, Rolland, Mathieu +8
#Blé #Catalogue français #Diagnostic RT- PCR #Diagnostic RT-PCR #French catalog #Méthode de référence #Reference method #Résistance variétale #SBCMV #Varietal resistance #WSSMV #Wheat
paper · doi:10.17180/9kvd-5a10
The mosaic viruses of cereals, Soil-Borne Cereal Mosaic (SBCMV) and Wheat Spindle Streak Mosaic Virus (WSSMV) are RNA viruses transmitted by a soil microorganism: Polymyxa graminis. Wheat crops are increasingly affected by the virus, resulting in large yield losses and up to now, only the varietal resistance makes it possible to fight against these mosaics. Currently, serological tests (ELISA) are performed to support visual scores in order to confirm varietal resistance in the context of varieties registration in the National Catalogue by GEVES and as part of post registration tests by ARVALIS Plant Institute. But since 2009, questions have been raised concerning the stability of sera performance depending on the supplier. The objective of this study was to define a reliable reference method to confirm the resistance of wheat varieties to WSSMV (bymovirus) and to SBCMV (furovirus), depending on the reproducibility, sensitivity, and cost of methods. In 2009-2010, the laboratories optimized a method for molecular detection by RT-PCR, by choosing primer pairs of Vaïanopoulos (2006) c2F/c1R for WSSMV and FURO2-F / R for SBCMV, (2009) optimized by BioGEVES in 2010, followed by agarose gel electrophoresis. In 2010-2011, ring tests showed a very good reproducibility of RT-PCR tests (> 95%), with rare cases of false positives, and a good reproducibility of ELISA tests (> = 89%), with some cases of false negatives, in connection with the sensitivity of each method. A simplified RTPCR protocol, “Jus GES”, was not retained, due to a lower sensitivity than ELISA tests, despite its lower cost than RT-PCR. For the registration of wheat varieties to the French catalogue, the detection reference method remains the DAS-ELISA test, conducted by GEVES. This method has proven its robustness with a good concordance with the visual scores, a sufficient sensitivity and a cost eight times lower than RT-PCR. But in case of defective sera, it will now be possible to use a test by RT-PCR; this service is now offered to the whole seed supply chain by GEVES. For the varieties in post-registration, the method used is the molecular method by RT-PCR.