Abstract: Tomato spotted wilt orthotospovirus (TSWV), a representative member of the Tospoviridae family. It causes serious damage to vegetables, such as tomato, pepper, pumpkin and celery. In previous study, the transcriptomic data analysis showed that Tag A could induce the expression of 10 genes (eg., Nitab4.5_ 0007569g0010 (CYP724B1), Nitab4.5_0001595g0020, Nitab4.5_0004234g0120)., Here, RT-qPCR was used to further verify the datas and found that the expression of Nitab4.5_0007569g0010(CYP724B1) gene was differently significant increased after Tag A treatment. CYP724B1 gene was silenced by virus-induced gene silencing (VIGS), the expression of the NSm and NSs genes were significantly increased compared to the control in the inoculated and systemic leaves. After CYP724B1 gene was overexpressed, the expression of the NSm and NSs genes were significantly decreased compared to the control in the inoculated and systemic leaves. These results indicate that Tag A could regulate the CYP724B1 gene to inhibit the expression of NSm and NSs to defense against TSWV infection.