Guadie Demsachew, Tesfaye Kassahun, Knierim Dennis, Winter Stephan, Abraham Adane
Institute of Biotechnology, Addis Ababa University, P.O.Box 1176, Addis Ababa, Ethiopia.
Ethiopian Biotechnology Institute, Ministry of Innovation and Technology, Addis Ababa, Ethiopia.
Virus Genes. 2019 Jun;55(3):339-345. doi: 10.1007/s11262-019-01655-1. Epub 2019 Mar 14.
Maize (Zea mays L.) is host for more than 50 virus species worldwide with Maize streak virus (MSV) (genus Mastrevirus) causing significant yield losses in Africa. A survey for viruses infecting maize was conducted in major growing regions of Ethiopia. To test for DNA viruses, in particular mastreviruses, rolling circle amplification was performed for the analysis of virus composition in assayed samples. Following the analysis of the entire virus genomes, three genetic groups, each representing distinct virus species, were identified. The first group was almost identical with the A-strain of MSV. The next sequence-cluster shared 96-98% identity with isolates of Maize streak reunion virus (MSRV) confirming the presence of this virus also in continental East Africa. Sequence analysis of additional virus genomes (each 2846 nt) in length revealed only a limited 70-71% nt identity with MSRV isolates and an even lower identity (< 64%) with sequences of mastreviruses described elsewhere. Our analysis suggests a novel virus species, which is tentatively named maize streak dwarfing virus (MSDV). The pairwise comparison of capsid protein and replication-associated protein (Rep) of the novel species revealed a limited identity of 63% and 68% with the respective protein sequences of MSRV. The incidence of the virus species in the maize regions of Ethiopia was studied across 89 samples collected during four growing seasons. PCR analysis with general and specific mastrevirus primers showed that MSV is the most incident virus (39.3%) followed by MSRV (14.6%) and MSDV (12.4%). Identification of three different mastrevirus species in a confined geographical location on the same host, maize, is unprecedented, and suggests that Ethiopia may be one of the potential hot spots for diversity of maize-infecting mastreviruses.
玉米（Zea mays L.）是全球50多种病毒的宿主，其中玉米条纹病毒（MSV）（ Mastrevirus属）在非洲造成了严重的产量损失。在埃塞俄比亚的主要种植区对感染玉米的病毒进行了调查。为了检测DNA病毒，特别是杆状病毒，进行了滚环扩增以分析检测样品中的病毒组成。在对整个病毒基因组进行分析后，确定了三个遗传组，每个遗传组代表不同的病毒种类。第一组与MSV的A株几乎相同。下一个序列簇与玉米条纹团聚病毒（MSRV）的分离株具有96-98%的同一性，证实了该病毒在东非大陆也存在。对另外长度为2846 nt的病毒基因组进行序列分析，结果显示与MSRV分离株的核苷酸同一性仅为有限的70-71%，与其他地方描述的杆状病毒序列的同一性更低（<64%）。我们的分析表明存在一种新型病毒，暂命名为玉米条纹矮化病毒（MSDV）。该新物种的衣壳蛋白和复制相关蛋白（Rep）的成对比较显示，与MSRV的相应蛋白序列的同一性分别为有限的63%和68%。在四个生长季节收集的89个样本中，研究了该病毒物种在埃塞俄比亚玉米种植区的发生率。使用通用和特异性杆状病毒引物进行的PCR分析表明，MSV是最常见的病毒（39.3%），其次是MSRV（14.6%）和MSDV（12.4%）。在同一宿主玉米的有限地理位置上鉴定出三种不同的杆状病毒物种，这是前所未有的，表明埃塞俄比亚可能是感染玉米的杆状病毒多样性的潜在热点之一。
