Mixed infection in tomato to ensure frequent generation of a natural reassortant between two subgroups of Cucumber mosaic virus
Mixed infection in tomato to ensure frequent generation of a natural reassortant between two subgroups of Cucumber mosaic virus
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DOI：
10.1007/s11262-009-0414-6
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发表时间：
2010-02
期刊：
影响因子：
1.6
通讯作者：
T. Maoka;Y. Hayano;M. Iwasaki;Koji Yoshida;C. Masuta
中科院分区：
文献类型：
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作者：
T. Maoka;Y. Hayano;M. Iwasaki;Koji Yoshida;C. Masuta
黄瓜花叶病毒（CMV）分为亚组I（sub-I）和亚组II（sub-II）。用单病斑分离法从番茄上分离到CMV-PF分离物，经血清学鉴定属于亚Ⅱ类，但具有亚Ⅰ类CMV的致病性。序列比较和系统发育分析表明，CMV-PF实际上是一个含有来自sub-I的RNA 1和2以及来自sub-II的RNA 3（I、I和II）的CMV分离物。设计了一种亚组特异性逆转录-聚合酶链反应（SS-RT-PCR），用于检测亚组I和亚组II之间的相关性。为每个亚组设计了6对基因组RNA特异性引物，这些引物成功扩增了其靶RT-PCR产物。在38个天然CMV分离物中，2个分离物（nos. 9-7和27-3）含有两个亚组的混合RNA。利用SLI技术分离了9-7的SLI后代，并进行了SS-RT-PCR分析，发现它们是含有来自sub-I的RNA 1和2以及来自sub-II的RNA 3（I、I和II）的抗性体。虽然根据以前的观察，CMV亚组之间的自然recritants被认为是罕见的，我们很容易发现两个分离株的recritants（I，I和II）在不同的番茄领域，这意味着番茄可能作为一个水库的混合感染的一代的CMV recritants可能由蚜虫。
Cucumber mosaic virus(CMV) is divided into subgroups I (sub-I) and II (sub-II). Isolate CMV-PF, which had been isolated from tomato by single lesion isolation (SLI), was classified in sub-II by serology, but it had the pathogenicity of sub-I CMVs. Sequence comparisons and phylogenetic analyses showed that CMV-PF was actually a reassortant CMV isolate containing RNAs 1 and 2 from sub-I and RNA 3 from sub-II (I, I, and II). A subgroup-specific reverse transcription–polymerase chain reaction (SS-RT–PCR) was devised to detect reassortants between sub-I and sub-II. Six primer sets specific to genomic RNAs were designed for each subgroup, and those primer sets successfully amplified their target RT–PCR products. Of 38 natural CMV isolates, two isolates (nos. 9-7 and 27-3) contained mixed RNAs of both subgroups. SLI-progenies of 9-7 were subsequently isolated by SLI usingVigna unguiculataand analyzed by SS-RT–PCR; they were found to be a reassortant containing RNAs 1 and 2 from sub-I and RNA 3 from sub-II (I, I, and II). Although natural reassortants between CMV subgroups were thought to be infrequent based on previous observations, we readily found two isolates of a reassortant (I, I, and II) in different tomato fields, implying that tomato may act as a reservoir of mixed infection in the generation of a CMV reassortant perhaps by aphids.