Virus-induced gene silencing (VIGS) is a technology for rapid gene functional analysis that depends on the degradation of viral RNA and is part of the natural defense mechanism in plants. Senecio cruentus is an important Compositae ornamental species that is plentiful and available in a variety of colors and has a typical blue variety that is rare in Compositae. These advantages make it a good material for studying the anthocyanin biosynthesis and blue flower formation mechanism. With the development of gene sequencing technology, the functions of many candidate genes that may be involved in anthocyanin biosynthesis in S. cruentus need to be identified. However, a stable and rapid genetic transformation system of S. cruentus is still lacking. Here, we screened two cultivars, 'Venezia' and 'Jseter', selected ScPDS and ScANS as test genes, and investigated the effect of developmental periods, bacterial cell concentrations and infection methods on gene silencing efficiency. The results showed that the silencing efficiency of S. cruentus leaves was low (13%), and it was less affected by the parameters. However, the transcription factor gene ScbHLH17 was still silenced by VIGS, which resulted in the loss of anthocyanin accumulation in leaves, and the expression levels of anthocyanin biosynthesis pathway (ABP) structural genes, including ScCHI, ScDFR3 and ScANS, were decreased significantly. The result proved that ScbHLH17 was an important transcription factor that regulated flower color formation in S. cruentus. In addition, ScANS-silencing phenotypes were observed in S. cruentus capitulum by vacuum-infiltrating S1 stage buds for 10 min after scape injection. In general, the present study provided an important technical support for the study of anthocyanin metabolism pathways in S. cruentus.

中文翻译：

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千里光中病毒诱导的基因沉默系统的建立和ScbHLH17的功能分析。

病毒诱导的基因沉默（VIGS）是一种用于快速基因功能分析的技术，该技术取决于病毒RNA的降解，并且是植物自然防御机制的一部分。千里光千里光是一种重要的菊科观赏植物，种类丰富，有多种颜色可供选择，并且具有典型的蓝色变种，在菊科中是罕见的。这些优点使其成为研究花色苷生物合成和蓝色花形成机理的良好材料。随着基因测序技术的发展，需要鉴定可能与克鲁维酵母中花色苷生物合成有关的许多候选基因的功能。然而，仍然缺乏稳定且快速的链球菌遗传转化系统。在这里，我们筛选了两个品种'Venezia'和'Jseter'，选择ScPDS和ScANS作为测试基因，并研究发育时期，细菌细胞浓度和感染方法对基因沉默效率的影响。结果表明，刺槐叶片的沉默效率较低（13％），受参数的影响较小。然而，转录因子基因ScbHLH17仍被VIGS沉默，导致叶片中花色苷的积累丢失，花色苷生物合成途径（ABP）结构基因，包括ScCHI，ScDFR3和ScANS的表达水平显着降低。结果证明，ScbHLH17是调控S. cruentus花色形成的重要转录因子。另外，在S中观察到ScANS沉默表型。花注射后，通过真空渗入S1阶段芽10分钟使刺槐变质。总的来说，本研究为S. cruentus中的花色苷代谢途径的研究提供了重要的技术支持。