Zhaolei Li, Jing Zhang, Xinxin Yang, Ruobin Lu, Hao He, Ziyan Xu, Yuan Chen, Xueping Zhou, Fangfang Li
Positive-sense RNA viruses using subgenomic RNAs (sgRNAs) cause severe crop losses, yet this conserved feature has rarely been exploited for antiviral engineering. Here, we constructed a virus-activated synthetic immune circuit, wherein viral sgRNA production drives host defense responses via a translation inhibition-transcription activation (TI-TA) module. An optimized translational repression element (dsBC) minimized basal expression while enabling virus-specific activation of resistance-inducing proteins (RIPs) by cognate viral sgRNA promoters. This circuit functioned against three major sgRNA-producing viruses-pepino mosaic virus (PepMV), tobacco mosaic virus (TMV), and cucumber mosaic virus (CMV)-in Nicotiana benthamiana, tomato, and Arabidopsis thaliana, with cross-resistance to related viruses. RIP expression was strictly triggered by viral infection, conferring robust resistance without detectable growth penalties. This programmable strategy provides a versatile platform for engineering resistance against diverse sgRNA-producing RNA viruses and offers a conceptual framework for developing synthetic antiviral immunity in plants.