Plant virus-based expression systems are an alternative expression platform for the production of clinically and industrially useful recombinant proteins. Nonetheless, due to a lack of viral vector with the commercial potentials, it is urgent to design and develop new, versatile, and efficient plant virus vectors. The genome of Tomato bushy stunt virus (TBSV) offers an attractive alternative to being modified as a vector for producing heterologous proteins in plants. Here, we developed a set of novel fusion and non-fusion TBSV-CP replacement vectors, which provide more flexible and efficient tools for expressing proteins of interest in plants. An alternative tobacco plant, Nicotiana excelsiana, was used in this study as a host for newly constructed TBSV vectors because the unwanted necrotic effects were reported on the commonly used Nicotiana benthamiana host associated with expression of TBSV-encoded P19 protein. The data showed that TBSV vectors caused a symptomless infection and overexpressed reporter gene in N. excelsiana leaves, demonstrating that N. excelsiana is an ideal host plant for TBSV-mediated heterologous gene expression. Moreover, a TBSV non-fusion vector, dAUG, shows the similar accumulation level of reporter proteins to that of TMV- and PVX-based vectors in side-by-side comparison and provides more flexible aspects than the previously developed TBSV vectors. Collectively, our newly developed TBSV expression system adds a new member to the family of plant viral expression vectors and meanwhile offers a flexible and highly effective approach for producing proteins of interest in plants. KEY POINTS: • The TBSV-based transient expression system has been significantly improved. • The necrotic effects caused by viral P19 protein were avoided by the usage of N. excelsiana as a host plant. • The expression level of the non-fusion vector was similar to the most effective virus vectors reported so far.

中文翻译：

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开发基于番茄浓密特技病毒的载体，用于在替代宿主 Nicotiana excelsiana 中融合和非融合表达异源蛋白。

基于植物病毒的表达系统是用于生产临床和工业上有用的重组蛋白的替代表达平台。尽管如此，由于缺乏具有商业潜力的病毒载体，迫切需要设计和开发新的、通用的、高效的植物病毒载体。番茄丛矮病毒 (TBSV) 的基因组提供了一种有吸引力的替代方法，可以替代被修饰为在植物中产生异源蛋白质的载体。在这里，我们开发了一组新的融合和非融合 TBSV-CP 替代载体，它们为表达植物中感兴趣的蛋白质提供了更灵活和有效的工具。替代烟草植物 Nicotiana excelsiana，本研究中使用 TBSV 作为新构建的 TBSV 载体的宿主，因为在与 TBSV 编码的 P19 蛋白表达相关的常用本氏烟草宿主上报告了不需要的坏死效应。数据表明，TBSV 载体在 N. excelsiana 叶中引起无症状感染和报告基因过表达，证明 N. excelsiana 是 TBSV 介导的异源基因表达的理想宿主植物。此外，TBSV 非融合载体 dAUG 在并排比较中显示出与基于 TMV 和 PVX 的载体相似的报告蛋白积累水平，并提供比以前开发的 TBSV 载体更灵活的方面。总的来说，我们新开发的 TBSV 表达系统为植物病毒表达载体家族增添了一个新成员，同时提供了一种灵活高效的方法来生产植物中感兴趣的蛋白质。要点： • 基于TBSV 的瞬时表达系统得到了显着改进。• 使用精良猪笼草作为寄主植物，避免了病毒 P19 蛋白引起的坏死效应。• 非融合载体的表达水平与迄今为止报道的最有效的病毒载体相似。