Evidence for three groups of sequence variants of beet necrotic yellow vein virus RNA 5

Abstract

About half of Japanese isolates of beet necrotic yellow vein virus (BNYVV) were found to contain RNA 5 molecules, which were also detected in virus isolates from China and France. Sequence comparisons of RNA 5 (nucleotides 327 to 1171) in 25 isolates showed that there are up to 8% sequence differences, and that RNA 5 variants fall into three groups: group I contains most of the Japanese and Chinese isolates, group II two Japanese isolates, and group III four French isolates. The group I isolates fall into three small clusters. In the 26 kDa coding region of RNA 5, there was a maximum of 1.5% nucleotide sequence differences (6 amino acid changes) within the group and 8.4% nucleotide sequence differences (17 amino acid changes) between the groups. Comparisons of the coat protein gene of RNA 2 revealed that most of the Japanese and Chinese isolates belonged to the A type strain, but some isolates were of the B type. The French isolates (P type) were closely related to those of the A type. Mixed infections of the two types of virus and the two groups of RNA 5 were detected in a small area of Hokkaido. BNYVV might have been introduced into Japan and China by a similar route from at least two origins. These results, together with other evidence, suggest that the three groups of RNA 5 variants separated from an original population a long time ago and, thereafter, the group I population diverged further into three clusters, which may have been associated with the A type strain rather than the B type.

Identification of amino acids of the beet necrotic yellow vein virus p25 protein required for induction of the resistance response in leaves of Beta vulgaris plants

“…The other six wt BNYVV isolates and their origins are listed in Table 1. Each of the virus isolates was recovered from infested soil as described previously (Miyanishi et al, 1999). The IV4, IP7, USTH and T41 isolates contained RNA1-RNA4, whilst the FP isolate contained the additional RNA5.…”

“…Sequences of RNA3 from natural BNYVV isolates were obtained as described previously (Miyanishi et al, 1999). Two specific primers, 3F (59-AGTTGTTGTGTTTTCTGATC-39, nt 4082427) and the reverse primer 3R (59-CCGTGAAATCACGTGTAGTT-39, complementary to nt 124921268) were used (Saito et al 1996).…”

“…The RNA3-encoded p25 protein is responsible for the induction of rhizomania symptoms of sugar beet roots and severe symptom expression in Chenopodiaceae hosts (Tamada et al, 1989Jupin et al, 1992;Klein et al, 2007), whereas RNA4-encoded p31 is involved in efficient vector transmission and root-specific silencing suppression (Rahim et al, 2007). RNA5, which is also associated with symptom severity, has been found in small areas of Europe and in most areas of Asia (Miyanishi et al, 1999;Schirmer et al, 2005;Ward et al, 2007).…”

Evidence for the presence of Beet necrotic yellow vein virus types A and B in Poland

“…Types A and B are distributed worldwide and contain only four RNAs. Type A is present in most European countries, Iran, North America, China and Japan, whereas type B is detected frequently in France and Germany, and in Sweden, China and Japan occasionally (SAITO et al 1996;MIYANISHI et al 1999;LENNEFORS et al 2000;SOHI and MALEKI 2004). The isolates which contain five RNAs represent type P of BNYVV and so far have been found only in France (KOENIG et al 1999), the UK (HARJU et al 2002) and also in Kazakhstan .…”

New natural weed host Raphanus raphanistrum L. (Brassicaceae) for Beet necrotic yellow vein virus and its vector Polymyxa betae Keskin

“…Our BNYVV isolates were not digested by these restriction enzymes, suggesting that the isolate from R. raphanistrum belongs to the A type strain (Figure 3). The A type, the most widespread strain (Schirmer et al, 2005), has been previously detected in Turkey (Kruse et al, 1994;Kutluk Yilmaz et al, 2007); the B type strain is more restricted and mainly found in Germany, France (Kruse et al, 1994;Koenig et al, 2008), Japan (Miyanishi et al, 1999), and China (Li et al, 2008).…”