Characterization of potato and tobacco isolates of Cucumber mosaic virus from Syria and the first report on CMV satellite RNA from potato

Cucumber mosaic virus (CMV) has been reported from potato production areas in Europe, USA, Japan and more frequently in regions with warm climates such as Egypt, India, Saudi Arabia and Syria. As it is considered as an uncommon virus in potato, the characterization of potato isolates of CMV is far behind those from other hosts. In addition to potato, CMV is a common virus infecting many crops in Syria, but nothing is known about its molecular characteristics. The present study aimed to characterize Syrian CMV isolates collected from potato and neighboring tobacco fields. All potato isolates of CMV (total of four) co-infected potato plants with Potato virus Y (PVY) which is the most frequent potato virus in Syria. According to the sequence analyses of the coat protein (CP) coding region, three potato and three tobacco CMV isolates were found to be closely related regardless of the host species or geographic origin, and all belonged to the IA strain subgroup of CMV. A potato CMV isolate, PoCMV7-5, readily infected solanaceous plants in which it induced systemic infection, but was less infectious to other hosts including those of Leguminosae and Cucurbitaceae. When inoculated on potato plants, PoCMV7-5 alone or with various PVY strains was able to cause local but not systemic infection in all potato cultivars inoculated. PoCMV7-5 contained heterogeneous variants of satellite RNA which varied in length due to A or/and T deletion/insertion at approximate nucleotide position 225‒240. This is the first report on CMV satellite RNA from potato

シリアサンジャガイモYウイルス ニ タイスル ポリクローナルコウタイ ノ ショサクセ

ジャガイモYウイルス(PVY)はシリアのジャガイモ生産における主要ウイルスの一つとされ,ジャガイモ生産の阻害要因となっている。PVY感染の無い種イモの生産と供給が主要な防除手段であるが,そのためには,効果的なウイルス検査法が必要である。酵素結合抗体法(ELISA)は複数種類のジャガイモウイルス検出には最も一般的な技術であるが,それぞれのウイルスに対して特異的な抗血清が利用できることが必須条件となる。本研究では,シリアに発生したPVY分離株を純化し,ウサギに免疫することにより抗血清をはじめて作製した。この抗血清を利用し多くのシリア産PVYを用いたELISAによる検討では,市販の抗血清と同等の検出能力を有し,両抗血清間に結果の相違は認められなかった。また,非特異的反応も生じなかった。さらに,検出限界は高かった。以上より,本研究ではシリアで分離されたPVYに対して初めてシリア国産抗血清を得ることができ,抗血清の恒常的輸入を不要にしたことに大きな意義があると考えられる。Potato virus Y (PVY) is reported to be the main virus occurring in potato fields and it increases the cost of potato production in Syria. Producing and utilizing of certified seed potatoes with minimum PVY infection is the main control key that requires efficient virus detection methods. Enzyme linked immunosorbent assay (ELISA) using specific antisera is the most common method for the detection of potato viruses. In this study we report the production of PVY antiserum in Syria for the first time. This antibody was produced against a Syrian PVY isolate and its reliability was confirmed by testing a panel of PVY infected samples collected from Syria. The results of ELISA using this antibody were consistent with those obtained using Agdia PVY antibody and no significant differences were found. In addition this antibody was highly specific to PVY with undetectable cross reaction to plant proteins. Moreover it was shown to be very sensitive and PVY infection could be detected in highly diluted plant saps. Since this antibody was produced against a Syrian isolate of PVY it has advantages over imported PVY specific antiserum