Endogenous viral elements (EVEs) have been for the most part described in animals and to a less extent in plants. The endogenization was proposed to contribute toward evolution of living organisms via horizontal gene transfer of novel genetic material and resultant genetic diversity. During the last two decades, several full-length and fragmented EVEs of pararetroviral and non-retroviral nature have been identified in different plant genomes, both monocots and eudicots. Prior to this work, no EVEs have been reported in alfalfa (Medicago sativa L.), the most cultivated forage legume in the world. In this study, taking advantage of the most recent developments in the field of alfalfa research, we have assessed alfalfa genome on the presence of viral-related sequences. Our analysis revealed segmented EVEs resembling two dsDNA reverse-transcribing virus species: Soybean chlorotic mottle virus (family Caulimoviridae, genus Soymovirus) and Figwort mosaic virus (family Caulimoviridae, genus Caulimovirus). The EVEs appear to be stable constituents of the host genome and in that capacity could potentially acquire functional roles in alfalfa’s development and response to environmental stresses.

中文翻译：

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紫花苜蓿（Medicago sativa L.）内源性病毒序列的全基因组鉴定

内源性病毒元件 (EVE) 大部分已在动物中描述，在植物中的描述较少。提出内源化通过新遗传物质的水平基因转移和由此产生的遗传多样性来促进生物体的进化。在过去的二十年里，已经在不同的植物基因组中发现了几种具有副逆转录病毒和非逆转录病毒性质的全长和片段化的 EVE，包括单子叶植物和真双子叶植物。在这项工作之前，尚未在世界上种植最多的豆科牧草苜蓿 (Medicago sativa L.) 中报告 EVE。在这项研究中，利用紫花苜蓿研究领域的最新进展，我们评估了紫花苜蓿基因组中病毒相关序列的存在。我们的分析揭示了类似于两种 dsDNA 逆转录病毒种类的分段 EVE：大豆褪绿斑驳病毒（Caulimoviridae，大豆病毒属）和榕花叶病毒（Caulimoviridae，Caulimovirus 属）。EVE 似乎是宿主基因组的稳定成分，在这种能力下，它们可能在紫花苜蓿的发育和对环境压力的反应中获得功能性作用。