Medina-Salguero Andres X, Cornejo-Franco Juan F, Grinstead Sam, Mowery Joseph, Mollov Dimitre, Quito-Avila Diego F
Centro de Investigaciones Biotecnológicas del Ecuador, Escuela Superior Politécnica del Litoral, ESPOL, Guayaquil, Guayas, Ecuador.
National Germplasm Resources Laboratory, USDA-ARS, Beltsville, MD, United States of America.
PLoS One. 2021 Feb 5;16(2):e0241652. doi: 10.1371/journal.pone.0241652. eCollection 2021.
A mild isolate of Papaya ringspot virus type-P, abbreviated as PRSV-mild, from Ecuador was sequenced and characterized. The most distinguishing symptom induced by PRSV-mild was gray powder-like leaf patches radiating from secondary veins. In greenhouse experiments, PRSV-mild did not confer durable protection against a severe isolate of the virus (PRSV-sev), obtained from the same field. Furthermore, isolate specific detection in mixed-infected plants showed that PRSV-sev becomes dominant in infections, rendering PRSV-mild undetectable at 90-120 days post superinfection. Virus testing using isolate-specific primers detected PRSV-mild in two out of five surveyed provinces, with 10% and 48% of incidence in Santo Domingo and Los Ríos, respectively. Comparative genomics showed that PRSV-mild lacks two amino acids from the coat protein region, whereas amino acid determinants for asymptomatic phenotypes were not identified. Recombination events were not predicted in the genomes of the Ecuadorean isolates. Phylogenetic analyses placed both PRSV-mild and PRSV-sev in a clade that includes an additional PRSV isolate from Ecuador and others from South America.
对来自厄瓜多尔的一种番木瓜环斑病毒P型温和分离株（简称为PRSV-mild）进行了测序和特征分析。PRSV-mild诱导的最明显症状是从次生叶脉辐射出的灰色粉末状叶斑。在温室试验中，PRSV-mild不能对从同一田地获得的该病毒的强毒株（PRSV-sev）提供持久保护。此外，对混合感染植株进行的分离株特异性检测表明，PRSV-sev在感染中占主导地位，在二次感染后90-120天PRSV-mild变得无法检测到。使用分离株特异性引物进行的病毒检测在五个被调查省份中的两个检测到了PRSV-mild，在圣多明各和洛斯里奥斯的发病率分别为10%和48%。比较基因组学表明，PRSV-mild的外壳蛋白区域缺少两个氨基酸，而未鉴定出无症状表型的氨基酸决定因素。在厄瓜多尔分离株的基因组中未预测到重组事件。系统发育分析将PRSV-mild和PRSV-sev置于一个进化枝中，该进化枝包括来自厄瓜多尔的另一种PRSV分离株和来自南美洲的其他分离株。
