Citrus Research International, Nelspruit, 1200, South Africa.
Department of Genetics, Stellenbosch University, Matieland, 7602, South Africa.
Plant Dis. 2020 Sep;104(9):2362-2368. doi: 10.1094/PDIS-12-19-2586-RE. Epub 2020 Jul 13.
Two isolates of the T68 genotype of citrus tristeza virus (CTV) were derived from a common source, GFMS12, by single aphid transmission. These isolates, named GFMS12-8 and GFMS12-1.3, induced stem pitting with differing severity in 'Duncan' grapefruit ( [Macfad.]). Full-genome sequencing of these isolates showed only minor nucleotide sequence differences totaling 45 polymorphisms. Numerous nucleotide changes, in relatively close proximity, were detected in the p33 open reading frame (ORF) and the leader protease domains of ORF1a. This is the first report of full-genome characterization of CTV isolates of a single genotype, derived from the same source, but showing differences in pathogenicity. The results demonstrate the development of intragenotype heterogeneity known to occur with single-stranded RNA viruses. Identification of genetic variability between isolates showing different pathogenicity will enable interrogation of specific genome regions for potential stem pitting determinants.
两个 T68 基因型的柑橘衰退病毒（CTV）分离株来源于一个共同的来源 GFMS12，通过单一蚜虫传播。这些分离株，命名为 GFMS12-8 和 GFMS12-1.3，在‘邓肯’葡萄柚（[Macfad.]）中引起不同严重程度的茎陷斑。这些分离株的全基因组测序仅显示出总计 45 个多态性的微小核苷酸序列差异。在 p33 开放阅读框（ORF）和 ORF1a 的前导蛋白酶结构域中，检测到大量相对接近的核苷酸变化。这是首次报道源自同一来源但致病性不同的单一基因型 CTV 分离株的全基因组特征。结果表明，与单链 RNA 病毒一样，发生了基因型内异质性的发展。鉴定表现不同致病性的分离株之间的遗传变异将能够针对潜在的茎陷斑决定因素对特定基因组区域进行检测。
