两种葫芦科病毒的分子检测和致病性研究

 小西葫芦黄化花叶病毒(ZYMV)和黄瓜花叶病毒(CMV)是浙江及其周边地区侵染葫芦科植物最主要的病毒种类。本文通过RT-PCR和基因克隆,获得了侵染南瓜的CMV杭州分离物(HZ01S10)的3'端序列,通过CP氨基酸序列同源性分析,确定其属于CMV亚组I;分别以³²P标记的ZYMV和CMV基因组cDNA作为探针,用RNA点杂交方法定点检测了浙江地区自然感病的葫芦科作物中以上2种病毒的发生情况。ZYMV和CMV在葫芦科作物上的发生表现出显著的季节性差异:夏季CMV发生普遍,只有部分南瓜和甜瓜感染ZYMV;ZYMV则主要发生在秋季,同一时期未检测到CMV。此外,幼苗期接种试验显示:以上2种病毒对西葫芦(早青一代)、丝瓜(中长)、黄瓜(津绿4号)的致病性存在明显差异,供试西葫芦对ZYMV比较敏感,供试丝瓜对CMV更敏感,而供试黄瓜品种对以上2种病毒均表现抗病。复合侵染在丝瓜和西葫芦上加重病害发生程度。

Molecular detection and pathogenic testing of two viruses infecting cucurbitaceous crops

Zucchini yellow mosaic virus (ZYMV) and Cucumber mosaic virus (CMV) are important viruses infecting cucurbitaceous crops in Zhejiang, China. The 3 ' end sequence of CMV- HZ01S10 originally isolated from Cucurbita moschata in Hangzhou, Zhejiang Province, was obtained with RT-PCR products. This isolate was then found belonging to CMV sub-group I according to its amino acid similarity of coat protein. With 32P labeled probes for ZYMV and CMV, occurrence of these two viruses of natural infection from Zhejiang Province was investigated by RNA spot hybridization, with samples collected from fixed fields respectively. ZYMV and CMV exhibited obvious seasonal differences for their natural occurrence. CMV was found to be the main virus in summer, only some C. moschata and Cucumis melo were found to be infected by ZYMV. However ZYMV was prevalent in autumn. Pathogenic tests for ZYMV and CMV were compared on varieties of Cucurbita pepo(Zaoqing Yidai), Luffa cylindrica (Zhongchang)and Cucumis sativus (Jinglu 4) by inoculation of seedlings in greenhouse, and obvious difference of symptoms exhibited among the varieties tested. The tested variety of L. cylindrica was more sensitive to the infection of CMV, and the tested C. pepo was more sensitive to ZYMV infection. Complex infection by CMV and ZYMV usually caused severe symptoms on L. cylindrica and C. pepo but not on C. sativus.