侵染南瓜的小西葫芦黄化花叶病毒的分离与鉴定

1999年秋在杭州一株表现典型黄化花叶的南瓜(Cucuribita moschata)上分离获得一株线状病毒HZ00s1.该病毒分离物在葫芦科作物(Cucuribitaceae)上引起系统症状.经寄主反应测定、病毒形态学和寄主组织病变观察, 初步确定该病毒为小西葫芦黄化花叶病毒(Zucchini yellow mosaic virus, ZYMV).对ZYMV杭州分离物(HZ00s1)的外壳蛋白序列及3 端非编码区进行了克隆及序列测定,并与ZYMV Conneticut分离物、Florida分离物、California分离物以及WMV2 Tonga分离物进行了同源性分析.结果显示:HZ00s1分离物与其它3种ZYMV分离物CP基因核酸序列同源性为93%～94%,而与WMV2 Tonga分离物的同源性仅为67%,来自美国的3种ZYMV分离物之间的同源性高达95%～99%.HZ00s1分离物与其它3个ZYMV分离物CP氨基酸序列同源性在95%～98%之间.因此确定在杭州地区葫芦科作物上有ZYMV的发生.

Identification of a zucchini yellow mosaic virus infecting squash in Hangzhou

A filamentous virus was isolated from naturally infected squash (Cucuribita. moschata L. ), showing yellow mosaic in Hangzhou,Zhejiang Province , in autumn 1999. This virus was found to cause systemic symptoms on all the Cucuribitaceae plants tested. It was identified as zucchini yellow mosaic virus (ZYMV) by host reaction tests, morphological characteristics observations and tissue alteration tests. The 3' end sequence, containing the coat protein (CP) gene and the 3' untranslated region of this virus, was obtained by RT-PCR and sequenced. Sequence alignment of CP genes was carried out in compare with three American ZYMV isolates, including the Conneticut isolate, Florida isolate and California isolate, and Tonga isolate of Watermelon mosaic virus 2 (WMV2). ZYMV HZOOsl had 93%-94% homology of nucleotide sequence with other three documented ZYMV isolates, whereas its sequence similarity to WMV2 Tonga isolate was found to be as low as 67%. Meanwhile, sequence similarity between the three America ZYMV isolates was 95% to 99%. Homology of deduced amino acid sequence of CP between HZOOsl and three other ZYMV isolates was 95%-98%. Our results proved the occurrence of ZYMV as a principal pathogenic virus on Cucuribitaceae crops in South part of China.