Transfer and modification of NLR proteins for virus resistance in plants

- NLR proteins confer resistance to multiple pathogens, including viruses.
- Natural variation represents a vast source of NLRs with desired specificities.
- NLRs can often be directly transferred between closely related species, but not between unrelated plants.
- Recognition can be enhanced through mutagenesis of NLRs.
- Modification of an NLR sensor to be cleaved by a viral protease can generate novel recognition.

NLR proteins confer resistance to multiple types of biotrophic pathogens, including viruses. NLRs are highly variable in sequence, suggesting that they are under selection pressure, but also that they may be manipulated to generate proteins with new recognition specificities. However, transferring of effective NLRs and engineering new specificities is subject to a number of constraints. Recent insights into NLR function suggest a number of reasons for these difficulties and new techniques have increased our ability to identify effective NLRs. This review discusses how this new information may allow researchers to better take advantage of the potential of NLRs for creating virus-resistant plants, including the identification, modification and transfer of NLRs as well as re-engineering NLRs to recognize viruses based on viral protein function.