Plant viruses are a group of intracellular pathogens that persistently threaten global food security. Significant advances in plant virology have been achieved by Chinese scientists over the last 20 years, including basic research and technologies for preventing and controlling plant viral diseases. Here, we review these milestones and advances, including the identification of new crop‐infecting viruses, dissection of pathogenic mechanisms of multiple viruses, examination of multilayered interactions among viruses, their host plants, and virus‐transmitting arthropod vectors, and in‐depth interrogation of plant‐encoded resistance and susceptibility determinants. Notably, various plant virus‐based vectors have also been successfully developed for gene function studies and target gene expression in plants. We also recommend future plant virology studies in China.

Geminiviruses are plant viruses with limited coding capacity. Geminivirus-encoded proteins are traditionally identified by applying a 10-kDa arbitrary threshold; however, it is increasingly clear that small proteins play relevant roles in biological systems, which calls for the reconsideration of this criterion. Here, we show that geminiviral genomes contain additional ORFs. Using tomato yellow leaf curl virus, we demonstrate that some of these small ORFs are expressed during the infection, and that the encoded proteins display specific subcellular localizations. We prove that the largest of these additional ORFs, which we name V3, is required for full viral infection, and that the V3 protein localizes in the Golgi apparatus and functions as an RNA silencing suppressor. These results imply that the repertoire of geminiviral proteins can be expanded, and that getting a comprehensive overview of the molecular plant-geminivirus interactions will require the detailed study of small ORFs so far neglected.

Endogenous target mimecry of an miRNA affects nicotine biosynthesis.

Plant diseases caused by invading plant viruses pose serious threats to agriculture production in the world, and the antiviral engineering initiated by molecular biotechnology has been an effective strategy to prevent and control plant viruses. Recent advances in CRISPR/Cas systems-mediated DNA or RNA editing/interference in plants make them become very attractive tools applied in the plant protection field. Here, we review the development of CRISPR/Cas systems, and summarize their applications in controlling different plant DNA and RNA viruses by targeting viral sequences or susceptible host genes. We list some potential recessive resistance genes which can be utilized in antiviral breeding, and emphasize the importance and a promising perspective of recessive resistance genes-based antiviral breeding to generate transgene-free plants without development defects. Finally, we discuss the challenges and opportunities for the application of CRISPR/Cas techniques in the prevention and control of plant viruses in the field.