*Article* **Establishing a Virus-Induced Gene Silencing System in** *Lycoris chinensis*

**Guanghao Cheng 1,2,3,†, Xiaochun Shu 1,2,3,†, Zhong Wang 1,2,3, Ning Wang 1,2,3 and Fengjiao Zhang 1,2,3,\***

	- **\*** Correspondence: fengjiao@cnbg.net
	- † These authors contributed equally to this work.

**Abstract:** *Lycoris* is an important plant with both medicinal and ornamental values. However, it does not have an efficient genetic transformation system, which makes it difficult to study gene function of the genus. Virus-induced gene silencing (VIGS) is an effective technique for studying gene functions in plants. In this study, we develop an efficient virus-induced gene-silencing (VIGS) system using the leaf tip needle injection method. The widely used TRV vector is constructed, and the *Cloroplastos Alterados 1* (*CLA1*) and *Phytoene Desaturase* (*PDS*) genes are selected as visual indicators in the VIGS system. As a result, it is observed that leaves infected with TRV-*LcCLA1* and TRV-*LcPDS* both show a yellowing phenotype (loss of green), and the chlorosis range of TRV-*LcCLA1* was larger and deeper than that of TRV-*LcPDS*. qRT-PCR results show that the expression levels of *LcCLA1* and *LcPDS* are significantly reduced, and the silencing efficiency of *LcCLA1* is higher than that of *LcPDS*. These results indicate that the VIGS system of *L. chinensis* was preliminarily established, and *LcCLA1* is more suitable as a gene-silencing indicator. For the monocotyledonous plant leaves with a waxy surface, the leaf tip injection method greatly improves the infiltration efficiency. The newly established VIGS system will contribute to gene functional research in *Lycoris* species.

**Keywords:** *Lycoris*; VIGS system; leaf tip injection; infiltration efficiency; indicator genes
