Virus-Induced Gene Silencing (VIGS) in and Functional Analysis of .

, renowned for its large inflorescences and a diverse range of colors, highlights a significant limitation in current gene function research, which is the lack of effective molecular genetic tools. This study utilized a (TRV)-based virus-induced gene silencing (VIGS) system to investigate gene function through posttranscriptional gene silencing in for the first time. The ortholog of () in , termed , was identified. Infection of tissue-cultured seedlings with TRV- led to photobleaching of the leaves. Additionally, infection with TRV containing the fragment in the flowers resulted in decreased anthocyanin production in sepals and a lightening of sepal coloration in the infected flowers. The phenomena and RT-qPCR results proved that the and genes of hydrangea were successfully silenced via the vacuum infiltration method. Furthermore, the introduction of TRV- revealed a decrease in delphinidin-3-glucoside content in sepals and caused a color change in the sepals from blue to pink. This study demonstrated that the TRV-VIGS system was successfully established in and effectively applied to the function analysis of .