Evidence for seed transmission of sweet potato symptomless virus 1 in sweet potato (Ipomoea batatas)

Sweet potato symptomless virus 1 (SPSMV-1) is a member of genus Mastrevirus, in the family Geminiviridae. SPSMV-1 was detected from sweet potato (Ipomoea batatas) seedlings by small-RNA deep-sequencing. PCR analysis indicated that SPSMV-1 was detected in 12 out of 114 individual sweet potato seedlings from seeds collected from a SPSMV-1-infected sweet potato plant, and additionally, detected in whole seeds, seed coats attached with endosperm, and in embryos. The complete genome of the virus was subsequently cloned by using a polymerase chain reaction (PCR) method with back-to-back (full) primer pairs from sweet potato seedlings and seeds. In summary, the results suggest that SPSMV-1 may be a seed-borne virus and a seed transmissible virus in sweet potato. To our knowledge, this is the first evidence for seed transmission of SPSMV-1, and seed transmission under natural conditions for any mastrevirus as well.