PDF(Pubmed)
Abstract：
Tomato leaf curl New Delhi virus (ToLCNDV), a bipartite Begomovirus belonging to the family Geminiviridae, causes severe damage to many economically important crops worldwide. In the present study, pathogenicity of Asian (ToLCNDV-In from Pakistan) and Mediterranean isolates (ToLCNDV-ES from Italy) were examined using infectious clones in tomato plants. Only ToLCNDV-In could infect the three tomato cultivars, whereas ToLCNDV-ES could not. Genome-exchange of the two ToLCNDVs revealed the ToLCNDV DNA-A segment as the main factor for ToLCNDV infectivity in tomato. In addition, serial clones with chimeric ToLCNDV-In A and ToLCNDV-ES A genome segments were generated to identify the region determining viral infectivity in tomatoes. A chimeric clone carrying the ToLCNDV-In coat protein (CP) exhibited pathogenic adaptation in tomatoes, indicating that the CP of ToLCNDV is essential for its infectivity. Analyses of infectious clones carrying a single amino acid substitution revealed that amino acid at position 143 of the CP is critical for ToLCNDV infectivity in tomatoes. To better understand the molecular basis whereby CP function in pathogenicity, a yeast two-hybrid screen of a tomato cDNA library was performed using CPs as bait. The hybrid results showed different interactions between the two CPs and Ring finger protein 44-like in the tomato genome. The relative expression levels of upstream and downstream genes and Ring finger 44-like genes were measured using quantitative reverse transcription PCR (RT-qPCR) and compared to those of control plants. This is the first study to compare the biological features of the two ToLCNDV strains related to viral pathogenicity in the same host plant. Our results provide a foundation for elucidating the molecular mechanisms underlying ToLCNDV infection in tomatoes.
摘要：
番茄曲叶新德里病毒(ToLCNDV),属于双子病毒科的两体Begomovirus，对全世界许多重要经济作物造成严重损害。在本研究中,使用番茄植物中的感染性克隆检查了亚洲（来自巴基斯坦的ToLCNDV-In）和地中海分离株（来自意大利的ToLCNDV-ES）的致病性。只有ToLCNDV-In可以感染三个番茄品种，而ToLCNDV-ES不能。两种ToLCNDV的基因组交换揭示了ToLCNDVDNA-A片段是番茄中ToLCNDV感染性的主要因素。此外,产生具有嵌合ToLCNDV-InA和ToLCNDV-ESA基因组区段的连续克隆,以鉴定决定番茄中病毒感染性的区域。携带ToLCNDV-In外壳蛋白（CP）的嵌合克隆在番茄中表现出致病性适应，表明ToLCNDV的CP对其传染性至关重要。对携带单个氨基酸取代的感染性克隆的分析表明，CP143位的氨基酸对于番茄中的ToLCNDV感染性至关重要。为了更好地了解CP在致病性中起作用的分子基础，使用CPs作为诱饵对番茄cDNA文库进行酵母双杂交筛选。杂种结果表明，番茄基因组中两种CP与环指蛋白44样之间的相互作用不同。使用定量逆转录PCR(RT-qPCR)测量上游和下游基因以及环指44样基因的相对表达水平,并与对照植物的相对表达水平进行比较。这是第一个在同一宿主植物中比较与病毒致病性有关的两株ToLCNDV的生物学特征的研究。我们的研究结果为阐明番茄中ToLCNDV感染的分子机制提供了基础。
