First report of Beet soil‐borne virus on sugar beet in China

Abstract

Prevalence of yam potyviruses in the French Caribbean islands of Guadeloupe was evaluated in 142 samples collected from yams showing symptoms of mosaic and mottling and belonging to Dioscorea rotundata (52 samples), D. alata (52 samples) and D. trifida (38 samples). Samples were screened by enzyme-linked immunosorbent assay (ELISA) with universal potyvirus monoclonal antibodies (AGDIA) and by immunocapture reverse-transcriptase polymerase chain reaction (IC-RT-PCR) for the specific detection of Yam mosaic virus (YMV) (Bousalem et al ., 2000a) and Yam mild mosaic virus (YMMV) (Bousalem et al ., 2003).Fifteen percent of the samples were positive in the broad-spectrum ELISA used but negative in both the specific IC-RT-PCR tests used, suggesting one or more other potyviruses might be present in the ELISA-positive samples. The highest proportion was in D. rotundata (15/52; 29%), followed by D. trifida (5/38; 13%), and D. alata (2/52; 4%). In an attempt to characterize those potential yam potyviruses, total RNA was extracted from one D. trifida sample (TGwadE2) and universal potyvirus degenerate primers (Colinet et al ., 1994) were used to amplify the core and C-terminal region of the coat protein (CP) and the 3 ′ untranslated region (3 ′ UTR) which are commonly used as markers of genetic relatedness of potyviruses.Sequence information generated (GenBank AY821494) from the cloned fragment was compared with sequences of other potyviruses by a BLAST search and by pairwise sequence comparison carried out on 209 potyviruses sequences aligned by the Clustal algorithm from the MegAlign software of DNASTAR package. The partial amino acid (aa) sequence available for the CP (152 aa) had the highest similarity with Zucchini yellow mosaic virus (66% identity) whereas the 3 ′ UTR (126 nucleotides) had the highest similarity with Potato virus Y (35% identity). Sequence comparisons of the CP (aa) and 3 ′ UTR with YMMV isolates (Bousalem et al ., 2003), YMV isolates (Bousalem et al ., 2000b) and Japanese yam mosaic virus isolate (JYMV, AB016500) showed the highest similarity at the amino acid level (62·5% identity) with the JYMV CP and highest similarity of the 3 ′ UTR with the YMMV (32% identity).According to molecular taxonomy, TGawdE2 isolate should be regarded as a distinct member of the genus Potyvirus (family Potyviridae ) and was tentatively named Dioscorea mosaic virus. References

Full length genome sequence of Polish isolate of Beet soil-borne virus confirms low level of genetic diversity.

“…In 2006 BSBV was reported for the first time in Poland (Borodynko et al, 2006). At the same time the virus was found in China (Wang et al, 2007). BSBV has a tripartite genome consisting of three positive-sense RNA molecules.…”

Complete Genome Sequences of Two Chinese Beet soil‐borne virus Isolates Provide Evidence that the Genome is Highly Conserved

“…Beet soil‐borne virus (genus Pomovirus ) was first isolated from sugar beet in England (Henry and Jones, 1986) and was later found in many other countries including Germany, France, The Netherlands, Belgium, Lithuania, Sweden, Finland, Italy, Spain, Switzerland, Austria, Hungary, Poland, Croatia, Slovakia, Iran, Turkey, Syria, the USA and Japan (Borodynko et al., 2006; Farzadfar et al., 2002; Meunier et al., 2003; Mouhanna et al., 2002; Ratti et al., 2005). In China, BSBV was identified for the first time in 2006 by Wang et al. (2007).…”

RNA silencing machinery contributes to inability of BSBV to establish infection in Nicotiana benthamiana: evidence from characterization of agroinfectious clones of Beet soil-borne virus

“…Since then, the virus was shown to be widespread in Europe [15], Turkey [16], the Middle East [17, 18], Iran [19] and the USA [20]. In addition, it has been reported in China [21], Japan [22], and more recently in Morocco [23] and Brazil [24]. The virus has been found alone in roots of sugar beet but also in association with other soil-borne viruses transmitted by P. betae [15], in particular the benyvirus Beet necrotic yellow vein virus (BNYVV), the causal agent of the rhizomania disease [25].…”