Genetic diversity and biological variation among California isolates of Cucumber mosaic virus
Genetic diversity and biological variation among California isolates of Cucumber mosaic virus
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DOI：
10.1099/vir.0.18673-0
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发表时间：
2003-01-01
影响因子：
3.8
通讯作者：
Falk, BW
中科院分区：
文献类型：
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作者：
Lin, HX;Rubio, L;Falk, BW
比较了黄瓜花叶病毒(CMV)加州分离物的遗传多样性和生物变异。根据它们在三种南瓜上的反应，这些南瓜分为五种致病类型，包括感病南瓜，具有常规抗性的甜瓜和商业上抗CMV的转基因南瓜。33个分离物在抗CMV转基因南瓜上侵染并出现症状。有42个分离物侵染抗CMV甜瓜，但只有25个分离物同时侵染两者。利用单链构象多态(SSCP)技术将81个加州分离株分为14个类群，并对SSCP图谱明显和难以区分的27个分离物的外壳蛋白(CP)基因进行了测序。对14株不同SSCP图谱的菌株进行了系统发育分析。79个分离物属于CMV IA亚群，2个分离物属于CMV IB亚群。这是美洲地区首次报道IB亚群分离株。所有CMV分离物的核苷酸同源性均大于或等于93.24%。CP基因变异与地理来源、采集年份、原寄主植物、CP氨基酸序列同源性程度以及克服转基因和/或常规抗性的能力之间没有相关性。用SSCP和序列分析方法比较了33个CMV在转基因南瓜和感病南瓜上的分离物。1个分离物在这两个寄主之间出现了序列差异，但这不是由于转基因抗性的重组或选择压力造成的。即使在CMV转基因材料出现之前，加利福尼亚州就已经存在能够感染具有常规和转基因CMV抗性的葫芦科植物的CMV分离物。
Genetic diversity and biological variation were compared for California isolates of Cucumber mosaic virus (CMV). These fell into five pathotypes based on their reactions on three cucurbits including a susceptible squash, a melon with conventional resistance and a commercial CMV-resistant transgenic squash. Thirty-three isolates infected and caused symptoms on CMV-resistant transgenic squash. Forty-two isolates infected the CMV-resistant melon, but only 25 isolates infected both. Single-strand conformation polymorphism (SSCP) analysis was used to differentiate 81 California isolates into 14 groups, and the coat protein (CP) genes of 27 isolates with distinct and indistinguishable SSCP patterns were sequenced. Fourteen isolates corresponding to the different SSCP patterns were also used for phylogenetic analysis. Seventy-nine isolates belonged to CMV subgroup IA, but two belonged to CMV subgroup IB. This is the first report of subgroup IB isolates in the Americas. All CMV isolates had a nucleoticle identity greater than or equal to 93.24 %. There was no correlation between CP gene variation and geographical origin, collection year, original host plant, or between the degree of CP amino acid sequence identity and the capacity to overcome transgenic and/or conventional resistance. SSCP and sequence analyses were used to compare 33 CMV isolates on CMV-resistant transgenic squash and susceptible pumpkin plants. One isolate showed sequence differences between these two hosts, but this was not due to recombination or selection pressure of transgenic resistance. CMV isolates capable of infecting cucurbits with conventional and transgenic CMV resistance were present in California, even before CMV transgenic material was available.