• Virus-induced gene silencing (VIGS) can be harnessed to sequence-specifically degrade host transcripts and induce heritable epigenetic modifications referred to as virus-induced post-transcriptional gene silencing (ViPTGS) and virus-induced transcriptional gene silencing (ViTGS), respectively. Both ViPTGS and ViTGS enable manipulation of endogenous gene expression without the need for transgenesis.
• Although VIGS has been widely used in many plant species, it is not always uniform or highly efficient. The efficiency of VIGS is affected by developmental, physiological and environmental factors. Here, we use recombinant Tobacco rattle viruses (TRV) to study the effect of temperature on ViPTGS and ViTGS using GFP as a reporter gene of silencing in N. benthamiana 16c plants.
• We found that unlike ViPTGS, ViTGS was impaired at high temperature. Using a novel mismatch-small interfering RNA (siRNA) tool, which precisely distinguishes virus-derived (primary) from target-generated (secondary) siRNAs, we demonstrated that the lack of secondary siRNA production/amplification was responsible for inefficient ViTGS at 29°C. Moreover, inefficient ViTGS at 29°C inhibited the transmission of epigenetic gene silencing to the subsequent generations.
• Our finding contributes to understanding the impact of environmental conditions on primary and secondary siRNA production and may pave the way to design/optimize ViTGS for transgene-free crop improvement.

中文翻译：

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温度通过次级小RNA调节病毒诱导的转录基因沉默

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  病毒诱导的基因沉默（VIGS）可用于序列特异性降解宿主转录物并诱导可遗传的表观遗传修饰，分别称为病毒诱导的转录后基因沉默（ViPTGS）和病毒诱导的转录基因沉默（ViTGS）。 ViPTGS 和 ViTGS 都可以在不需要转基因的情况下操纵内源基因表达。
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  尽管 VIGS 已广泛应用于许多植物物种，但它并不总是统一或高效。 VIGS 的效率受到发育、生理和环境因素的影响。在这里，我们使用重组烟草响铃病毒（TRV）来研究温度对 ViPTGS 和 ViTGS 的影响，并使用GFP作为N沉默的报告基因。本塞米亚纳16c 植物。
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  我们发现，与 ViPTGS 不同，ViTGS 在高温下会受到损害。使用新型错配小干扰 RNA (siRNA) 工具，该工具可以精确地区分病毒来源的（初级）siRNA 和靶标生成的（次级）siRNA，我们证明次级 siRNA 产生/扩增的缺乏是造成 29° ViTGS 效率低下的原因C。此外，29°C 下的低效 ViTGS 抑制了表观遗传基因沉默向后代的传递。
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  我们的发现有助于了解环境条件对初级和次级 siRNA 生产的影响，并可能为设计/优化 ViTGS 以实现无转基因作物改良铺平道路。