矮南瓜(Zucchini)黃化崁紋病毒之分離與鑑定

Abstract

一種在胡瓜葉片上引起嚴重嵌紋、萎黃、皺縮或杯狀形病徵之病毒，經單一局部病斑分離後，測定其寄主反應，發現該病毒之寄主範圍很廣，可在葫蘆科植物上造成系統性惑染，亦可在藜科之Chenopodium amaranticolor和C . C. quinoa，部分豆科植物及茄科中之Nicotiana benthamiana 及莧科之千日紅（Gomphrena globosa）造成感染。病毒粗汁液之耐稀釋度為10-4-10-5 ，耐保存度為9-11 天，耐熱度則視不同病毒分離株而為55-60 ℃或60-65℃。經電子顯微鏡觀察該病毒之粒子平均長度為740nm ，屬於potyvirus 群病毒。由美國康乃爾大學獲得之矮南瓜黃化嵌紋病毒（zucchini yellow mosaic virus ZYMV ）抗血清，利用ELISA 法測得9 個病毒分離株病組織粗汁液反應吸收值（Absorbance A405 ）最低為0.743 ，而健全者僅0.170。再以SDS-Immunodiffusion test，發現本省病毒與義大利之ZYMV 抗血清形成明顯沈澱帶，且與ZYMV-Florida 抗原所形成沈澱帶互為融合，證明本病毒與美國及義大利之ZYMV 有相同血清學類緣關係。ZYMV 之抗血清與WMV-l 及PRV 抗原則無反應。綜合上述各項結果，本病毒與國外報告之ZYMV 可能為相同之病毒。 A virus causing severe mosaic, chlorotic, rugose or leaf cupping symptoms on leaves of Cucumis sativus was obtained. Nine isolates of this virus showed no differences in host reactions and serological tests. The virus induced chlorotic local lesions in Chenopodium amaranticolor, C. quinoa and Gomphrena globosa. It produced mosaic symptoms in Cucumis melo ‘Honey Dew’, C. sativus and Luffa cylindrica. Zucchini squash infected with this virus showed prominent vein-chlorosis followed by severe mosaic, vein-banding, leaf-distortion and shoe-string symptoms. L. acutangula was also infected systemically. The virus could be recovered by back-inoculation from symptomless leaves of Phaseolus vulgaris ‘Bountiful’, P. vulgaris ‘Sanilac’, Pisum sat ivum ‘Taichung No. 11’, P. sativum ‘Alaska’, and Nicotiana benthamiana. Tests for physical properties showed a DEP of 10-4-10-5, LIV of 9-11 days and TIP of 55-65°C for the virus. In leaf-dip preparations of infected zucchini leaves the virus particles were seen to be filamentous with modal length of Ca. 740 nm. All 9 virus isolates in infected leaf extracts were tested against an antiserum to ZYMV obtained from New York (kindly provided to us by Dr.D. Gonsalves, Cornell University), the ELISA values A405 ranged from 0.743 to 2 or more as compared to 0.170 for the healthy control. In SDS-Immunodiffusion tests, the virus formed strong precipitin bands against antiserum to ZYMV-Italy (kindly provided by Dr. V. Lisa, Italy). In addition, antigens of our virus and ZYMV-Florida reacted with this antiserum by forming a fused precipitin band without spur formation. There were no reaction bands between ZYMV antiserum and WMV-1 or PRV. Based on host reactions, particle morphology, physical properties and serological relationships, we conclude that the virus is identical or closely related to zucchini yellow mosaic virus(ZYMV).