Prospects for engineering and improvement of cross-protective virus strains

•An outline of the effects of climate change on food security and human nutrition.•A virus' perspective through its infection and replication cycles.•Biochemical and visual analysis of virus-induced subcellular structures.•Understanding dynamic reprogramming networks will support virus impact predictions.•Genome editing by viral vectors could discover genes involved in cross-protection.•Potential mechanisms of, and current theories about, cross-protection.•Remote sensing identifies symptomatic plants e.g. due to reversion of mild strains?

Mild strain cross-protection is currently an important method for the production of high quality plant products; despite challenge from severe virus isolates the initial protecting strain precludes symptom development. The mechanism of cross-protection is not yet resolved as RNA silencing does not sufficiently explain the phenomenon. Six requirements have been put forward to ensure long-lasting protection. We propose two additional requirements for effective and durable mild strain cross-protection; mild strains based on knowledge of the mechanism and consideration of impacts to consumers. Future research on predicting phenotype from genotype and understanding virus-plant and virus-vector interactions will enable improvement of cross-protective strains. Shared international databases of whole ecosystem interactions across a wide range of virus patho- and symbiotic-systems will form the basis for making step-change advances towards our collective ability to engineer and improve mild strain cross-protection.