Citrus is one of the most important fruit crops globally and rising incidence of citrus yellow vein clearing virus (CYVCV) in citrus orchards is an increasing concern in India. CYVCV and Indian citrus ringspot virus (ICRSV) are assigned to the only two known species in the genus Mandarivirus. Both viruses naturally infect several citrus plants. ICRSV produces ringspots symptoms in Kinnow mandarin, whereas CYVCV induces vein clearing symptoms on Etrog citron and lemon. Leaf samples and bud sticks of different citrus cultivars, exhibiting diverse symptoms were collected during 2012–2014 from 18 locations of India. The genetic variability was assessed through analysis of the coat protein (CP) gene sequences. Out of the 15 CP gene sequences, 13 sequences were of 978 nucleotides (nts) and showed 96–99% sequence identity with CYVCV-Y1 isolate (JX040635.1). However, sequences from the isolates HI and DLI shared only 78% and 73% nucleotide sequence identity with CYVCV and ICRSV, respectively, and that may represent distinct CYVCV isolates in the genus Mandarivirus. In phylogenetic analysis also HI and DLI isolates clustered neither with CYVCV nor with ICRSV isolates.

中文翻译：

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柑橘黄脉清除病毒外壳蛋白基因遗传多样性及生物学变异感染不同柑橘品种

柑橘是全球最重要的水果作物之一，柑橘园中柑橘黄脉清除病毒 (CYVCV) 的发病率不断上升，这在印度越来越受到关注。CYVCV 和印度柑橘环斑病毒 (ICRSV) 被指定为 Mandarivirus 属中仅有的两个已知物种。这两种病毒都会自然感染几种柑橘类植物。ICRSV 在 Kinnow 柑橘中产生环斑症状，而 CYVCV 在 Etrog 柚子和柠檬中引起静脉清除症状。2012 年至 2014 年期间，从印度 18 个地点收集了表现出不同症状的不同柑橘品种的叶样本和芽茎。通过分析外壳蛋白 (CP) 基因序列来评估遗传变异性。在 15 个 CP 基因序列中，13 个序列为 978 个核苷酸 (nts)，与 CYVCV-Y1 分离株 (JX040635.1) 具有 96-99% 的序列同一性。1）。然而，来自分离株 HI 和 DLI 的序列分别与 CYVCV 和 ICRSV 仅具有 78% 和 73% 的核苷酸序列同一性，这可能代表了曼达里病毒属中不同的 CYVCV 分离株。在系统发育分析中，HI 和 DLI 分离株既不与 CYVCV 也不与 ICRSV 分离株聚集。