Evidence of seed-transmission of watermelon crinkle leaf-associated virus 1 (WCLaV-1) and WCLaV-2
A study was conducted to develop an ELISA test against watermelon crinkle leaf-associated virus 1 (Coguvirus citrulli, WCLaV-1 – EPPO Alert List) and watermelon crinkle leaf-associated virus 2 (Coguvirus henanense, WCLaV-2 – EPPO Alert List). The specificity of the antibodies obtained for WCLaV-1 and WCLaV-2 was confirmed. To further investigate seed contamination and transmission, an antigen-coating ELISA test was applied on 259 seedlings of watermelon (Citrullus lanatus) cv. ‘Crimson Sweet’ grown from commercial seeds and, as a result, 93.1% tested positive for WCLaV-1 and 17.8% for WCLaV-2. In an ELISA test on 40 seedlings of each of two other cultivars, 50% of seedlings were positive for WCLaV-1 and 25% for WCLaV-2 on cv. ‘Sugar baby’, and 92.5% of seedlings were positive for WCLaV-1 and 90% for WCLaV-2 on cv. ‘Fairfax’. The authors note that these results show high seed-transmission rates of WCLaV-1 and -2. They add that these viruses can remain infective inside seed for a long time, as they were recovered from seedlings grown from the oldest seed lot in the study (eight-year-old). Finally, further analysis showed that WCLaV-1 was inside in the cotyledon of the seed, and therefore sterilization and disinfection treatments of watermelon seeds are not effective to eliminate this virus.
Sources
Kauffmann CM, Vendramini M, Batista AMV, Mota HBS, Andrade IA, Cárdenas SBS, Queiroz PS, Silva BA, Correa JR, Nagata T (2025) Specific antibody production using recombinant proteins to elucidate seed transmission and nuclear localization in radicles of Coguvirus citrulli and Coguvirus henanense. Journal of Virological Methods 325, 114886.