Three distinct mechanisms facilitate genetic isolation of sympatric wheat streak mosaic virus lineages
Three distinct mechanisms facilitate genetic isolation of sympatric wheat streak mosaic virus lineages
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DOI：
10.1006/viro.2001.0841
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发表时间：
2001-04-10
期刊：
影响因子：
3.7
通讯作者：
Stenger, DC
中科院分区：
文献类型：
--
作者：
Hall, JS;French, R;Stenger, DC
交叉保护和载体传播瓶颈已被提出作为促进同域病毒谱系遗传分离的机制。利用分子标记技术对小麦条斑花叶病毒（WSMV）混合侵染的建立和消解进行了监测。来自美国的两个密切相关的WSMV株系（Type和Sidney 81）在小麦中表现出相互交叉保护，证实了这种经典现象是遗传隔离的机制。相比之下，美国菌株和墨西哥El巴坦3菌株之间的交叉保护是单方面的，不稳定的，只有部分有效。WSMV株在支持型和西德尼81混合感染的植物的单个叶片内的分布是空间不均匀的。菌株分布在单个分蘖共感染的植物也是异质的，有的包含型或西德尼81单独和一些包含两者。通过小麦曲螨传播，从同时感染Type和Sidney 81的源植物获得病毒，通常导致仅携带单一WSMV株系的试验植物。病毒株在共感染植物的空间细分可能有助于在收购过程中的载体传播瓶颈。总的来说，这三个不同的机制增强了个体病毒谱系的遗传隔离，并与随机过程一起，可以解释田间种群遗传多样性的产生和维持。(C)北京：科学出版社.
Cross-protection and vector transmission bottlenecks have been proposed as mechanisms facilitating genetic isolation of sympatric viral lineages. Molecular markers were used to monitor establishment and resolution of mixed infections with genetically defined strains of wheat streak mosaic virus (WSMV). Two closely related WSMV strains from the U.S. (Type and Sidney 81) exhibited reciprocal cross-protection in wheat, confirming this classic phenomenon as a mechanism of genetic isolation. In contrast, cross-protection between either U.S. strain and the divergent El Batan 3 strain from Mexico was unilateral, erratic, and only partially effective. Distribution of WSMV strains within individual leaves of plants supporting a mixed infection of Type and Sidney 81 was spatially nonuniform. Strain distribution among individual tillers of coinfected plants also was heterogeneous, with some containing either Type or Sidney 81 alone and some containing both. Transmission by wheat curl mites, acquiring virus from source plants simultaneously infected with both Type and Sidney 81, often resulted in test plants bearing only a single WSMV strain. Spatial subdivision of virus strains within coinfected plants likely contributed to vector transmission bottlenecks during acquisition. Collectively, these three distinct mechanisms enhance genetic isolation of individual viral lineages, and together with stochastic processes, may explain generation and maintenance of genetic diversity in field populations. (C) 2001 Academic Press.