Cucumber green mottle mosaic virus (CGMMV) is an emerging virus in the U.S. that has caused serious disease outbreaks to watermelon and several other cucurbit crops around the world. Although CGMMV is seed-borne, the mechanism of its transmission from seed to seedling was not fully understood. With increasing activities of off-shore hybrid seed production and global seed trade, there is a serious concern in planting a contaminated seed lot that may serve as a pathway for CGMMV dissemination. A recent study (supported in part by the USDA-SCRI CucCAP project), determined that CGMMV is seed-borne, but not seed transmitted through seed germination, and evaluated effectiveness of several detection methods. The ease of mechanical transmission could initiate a virus transmission from a contaminated seed to seedlings, resulting in a new infection. Understanding of the mechanism of virus transmission through seeds emphasizes the need to deploy a sensitive seed health assay and to ensure the use of a virus-tested seed lot of watermelon or other cucurbits for planting.
Sui, X., Li, R., Shamimuzzaman, M., Wu, Z., Ling, K. 2018. Understanding the transmissibility of cucumber green mottle mosaic virus in watermelon seeds and seed health assays. Plant Disease. https://doi.org/10.1094/pdis-10-18-1787-re.