Characterization of alphasatellites associated with monopartite begomovirus/betasatellite complexes in Yunnan, China

Abstract

BackgroundAlphasatellites are single-stranded molecules that are associated with monopartite begomovirus/betasatellite complexes.ResultsAlphasatellites were identified in begomovirus-infected plant samples in Yunnan, China. All samples that contained alphasatellites also contained betasatellites, but only some samples that contained betasatellites contained alphasatellites. Thirty-three alphasatellites were sequenced, and they ranged from 1360 to 1376 nucleotides. All alphasatellites contain 3 conserved features: a single open reading frame (Rep), a conserved hairpin structure, and an adenine-rich (A-rich) region. On the basis of the phylogenetic tree of the complete nucleotide sequences, the alphasatellites were divided into 3 types with one exception. Type 1 was associated with Tomato yellow leaf curl China virus (TYLCCNV)/Tomato yellow leaf curl China betasatellite (TYLCCNB) complex. Type 2 was associated with Tobacco curly shoot virus (TbCSV)/Tobacco curly shoot betasatellite (TbCSB) complex. Type 3 was associated with TbCSV/Ageratum yellow vein betasatellite (AYVB) complex. Within each type, nucleotide sequence identity ranged from 83.4 to 99.7%, while 63.4-81.3% identity was found between types. Mixed infections of alphasatellites associated with begomovirus/betasatellite complexes were documented.ConclusionsOur results validate that alphasatellites are only associated with begomovirus/betasatellite complexes. Thirty-three sequenced alphasatellites isolated from Yunnan Province, China were divided into 3 types--each associated with a specific begomovirus/betasatellite complex. Mix-infections of alphasatellite molecules may not be unusual.

Molecular characterization of Tobacco leaf curl Pusa virus, a new monopartite Begomovirus associated with tobacco leaf curl disease in India

“…Amino acid sequence identity; the highest sequence identities are shown in bold replicate autonomously, and may have originated from nanoviruses, as they encode a nanovirus-like replication associated protein (Rep)[24][25][26]. However, the role of alphasatellites in the etiology of begomovirus-induced diseases is not well understood.…”

Begomoviruses and Their Emerging Threats in South Korea: A Review

“…1c; Kon et al, 2007;Lee et al, 2011;Reddy et al, 2005;Seal et al, 2006a;Xie et al, 2010;Zhou et al, 2003). However, none has yet been reported from the NW .…”

“…1350 nucleotides) ssDNA molecule (termed alphasatellites, formerly DNA1) is usually found in association with OW begomovirus-betasatellite complexes (Mansoor et al, 1999(Mansoor et al, , 2000aNawazul-Rehman and Fauquet, 2009;Saunders and Stanley, 1999) but very recently, it has also been investigated to be associated with few NW begomovirus (Paprotka et al, 2010;Romay et al, 2010). In an extensive survey, Xie et al (2010) found that all samples those contain alphasatellites also contain betasatellites, but only few samples that contain betasatellites contain alphasatellites. In some cases, alphasatellites have been found to suppress viral symptoms (Nawaz-ul-Rehman and Fauquet, 2009).…”

Alphasatellitidae: a new family with two subfamilies for the classification of geminivirus- and nanovirus-associated alphasatellites

“…It is interesting to note that most geminivirus-associated alphasatellites described from the Old World have been associated with monopartite begomoviruses infections that frequently include the presence of betasatellites [39,52,56]. In the New World where monopartite begomoviruses are very rare, betasatellites have not been identified and alphasatellites have only ever been reported to occur in association with bipartite Begomovirus infections [10,32,37].…”