Features of the relationship between Tomato severe rugose begomovirus and Bemisa tabaci MEAM1 reveal that the virus is acquired during a probe lasting only one minute

Abstract

Tomato severe rugose virus (ToSRV) is a begomovirus found only in Brazil and has been the prevalent species affecting tomato crops in southwest and midwest of the country. Although the virus is known to be transmitted by Bemisia tabaci MEAM1, this study was undertaken to better characterize the relationship between ToSRV and whiteflies on tomato plants. The minimum acquisition and inoculation access periods, latent period, and virus retention time in the vector were determined. The results of transmission experiments showed that the minimum acquisition and inoculation access periods (AAP and IAP) for transmission of ToSRV by MEAM1 were 1 min and 5 min, respectively. After monitoring 50 individual adult whiteflies during a one-minute AAP on ToSRV-infected tomato leaves, 21 insects (42%) were able to acquire the virus, as confirmed by PCR. In contrast, one hundred insects that were individually allowed one-minute AAP on Tomato chlorosis virus (ToCV)-infected tomato leaves, which is a phloem-limited crinivirus, were unable to acquire the virus. The latent period of ToSRV in MEAM1 was 12–15 h, with adult whiteflies retaining the virus for 25 days. Although the tissue distribution of ToSRV in tomato has not been determined, the short AAP suggests that the virus may be present in mesophyll cells, from where it may be acquired during a one-minute feeding probe.