Estimation of the Size of Genetic Bottlenecks in Cell-to-Cell Movement of Soil-Borne Wheat Mosaic Virus and the Possible Role of the Bottlenecks in Speeding Up Selection of Variations in trans-Acting Genes or Elements
Estimation of the Size of Genetic Bottlenecks in Cell-to-Cell Movement of Soil-Borne Wheat Mosaic Virus and the Possible Role of the Bottlenecks in Speeding Up Selection of Variations in trans-Acting Genes or Elements
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DOI：
10.1128/jvi.01890-09
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发表时间：
2010-02-15
影响因子：
5.4
通讯作者：
Kishino, Hirohisa
中科院分区：
文献类型：
--
作者：
Miyashita, Shuhei;Kishino, Hirohisa
遗传瓶颈促进了种群中变异的固定和灭绝，病毒种群也不例外。为了研究植物RNA病毒在细胞间移动中是否存在遗传瓶颈，我们制备了携带两种不同荧光蛋白（黄色荧光蛋白（YFP）和青色荧光蛋白（CFP））的土传小麦花叶病毒RNA 2载体的构建体。用两种RNA 2载体和野生型RNA 1共接种宿主植物叶片显示两种载体RNA 2的分离，大多数在最初共感染的细胞的7至9个细胞间移动内。我们的统计分析表明，在从最初感染的细胞的第一次细胞间移动后，在相邻细胞中建立感染的病毒RNA基因组的数量平均为5.97 +/- 0.22，在第二次细胞间移动后为5.02 +/- 0.29。这些结果表明，植物RNA病毒在每一个细胞到细胞的运动中通常都面临狭窄的遗传瓶颈。此外，我们的模型表明，植物RNA病毒不是遭受瓶颈造成的适应性损失，而是利用重复的遗传瓶颈作为快速选择反式作用基因或元件中的适应性变体的基本要素，以响应宿主转移和宿主生长条件的变化。
Genetic bottlenecks facilitate the fixation and extinction of variants in populations, and viral populations are no exception to this theory. To examine the existence of genetic bottlenecks in cell-to-cell movement of plant RNA viruses, we prepared constructs for Soil-borne wheat mosaic virus RNA2 vectors carrying two different fluorescent proteins, yellow fluorescent protein (YFP) and cyan fluorescent protein (CFP). Coinoculation of host plant leaves with the two RNA2 vectors and the wild-type RNA1 showed separation of the two vector RNA2s, mostly within seven to nine cell-to-cell movements from individual initially coinfected cells. Our statistical analysis showed that the number of viral RNA genomes establishing infection in adjacent cells after the first cell-to-cell movement from an initially infected cell was 5.97 +/- 0.22 on average and 5.02 +/- 0.29 after the second cell-to-cell movement. These results indicate that plant RNA viruses may generally face narrow genetic bottlenecks in every cell-to-cell movement. Furthermore, our model suggests that, rather than suffering from fitness losses caused by the bottlenecks, the plant RNA viruses are utilizing the repeated genetic bottlenecks as an essential element of rapid selection of their adaptive variants in trans-acting genes or elements to respond to host shifting and changes in the growth conditions of the hosts.