Detection of a Geminivirus Infecting Sweet Potato in the United States

Abstract

In 1994, a sweet potato sample showing leaf curl symptoms was collected from the field in Louisiana. When graft-inoculated, Ipomoea nil cv. Scarlett O'Hara reacted with severe leaf distortion and chlorosis symptoms. I. aquatica reacted with a bright yellow mottle. The virus isolated was designated the United States isolate of sweet potato leaf curl virus (SPLCV-US). It was transmitted to I. nil by the sweet potato whitefly, Bemisia tabaci biotype B. DNA probes prepared with component A of pepper Huasteco geminivirus, with an isolate of bean golden mosaic geminivirus from Guatemala, with an isolate of tomato mottle geminivirus from Florida, and with an isolate of tomato yellow leaf curl geminivirus from the Dominican Republic (TYLCV-DR) hybridized with a 2.6-kb DNA band present in DNA extracts from plants infected with SPLCV-US. Probes prepared with the B component of these geminiviruses did not hybridize with these DNA extracts. We were unable to amplify SPLCV-US DNA products by polymerase chain reaction (PCR) in quantities that could be visualized by ethidium bromide staining. However, Southern blots from amplifications with primers AV494/AC1048 revealed PCR products of approximately 600 bp and 550 bp when hybridized with the TYLCV-DR probe. These results were consistently obtained from infected I. cordatotriloba and less consistently from I. aquatica or I. setosa. Fibrillar inclusions were occasionally seen, and granular aggregates of viruslike particles were observed in the nucleus of infected I. cordatotriloba. These results suggest that the virus isolated from sweet potato with leaf curl symptoms belongs to the geminivirus group.

Molecular characterization of begomoviruses and DNA satellites from Vietnam: additional evidence that the New World geminiviruses were present in the Old World prior to continental separation

“…This was further supported by the observations that they originated from the Old World and they shared very low overall sequence identity with the New World viruses [maximum 60.2 % for CoYVV (Ha et al, 2006); 58.4 % for CoGMV]. This scenario is very similar to that of the sweet potato viruses [sweet potato leaf curl virus (SPLCV), sweet potato leaf curl Georgia virus (SPLCGV) and Ipomoea yellow vein virus (IYVV)], which (i) are present in both the New World (Lotrakul et al, 1998) and the Old World , (ii) have genome organizations typical of Old World monopartite viruses (Lotrakul & Valverde, 1999), and (iii) formed an evolutionary lineage independent of both Old World and New World viruses . Our phylogenetic analysis, based on the complete DNA-A sequence, identified two geographically defined major clusters (Old World and New World viruses) and three other distinct clusters that were distinguished on the basis of host (legume, sweet potato and jute).…”

Detection of Corchorus golden mosaic virus Associated with Yellow Mosaic Disease of Jute (Corchorus capsularis)

“…The probe developed in the study could specifically detect the virus even up to 1:100 dilutions from infected plants and viruliferous whiteflies in NASH test. The nucleic acid based hybridization is a very common method for detection of begomoviruses [25]. The specific primers developed in the study detected the presence of the virus from two geographical regions.…”

Occurrence and genetic variability of partial coat protein gene of Sweet potato leaf curl virus (SPLCV) in Kenya

“…The virus also infects species of the Convolvulaceae which acts as alternative hosts after insect transmission (Valverde et al, 2003). SPLCV occurs worldwide (Briddon et al, et al 2006;Lotrakul et al, 1998). In Kenya, the virus was first reported in the Western region in a germplasm collection plot (Miano et al, 2006), but since then, no further work has been done to determine its overall distribution in the country.…”