Engineering Plant Immune Receptors to Build Durable, Broad-Spectrum Crop Resistance

Plant pathogens and pests remain among the most persistent threats to global food security, and a new review in Nature Reviews Bioengineering argues that the most promising route to sustainable crop protection lies in the deliberate engineering of the plant immune system itself. Written by Junzhu Wang, Yan Li, Yiguo Hong and Yule Liu, the review synthesizes a decade of mechanistic and structural work on plant immune receptors and sets out a translational roadmap for converting that knowledge into crops that resist disease without heavy pesticide inputs. Its central message is that immune receptors, once understood at atomic resolution, can be identified, transferred across species, and redesigned to recognize pathogens they would never encounter in nature.

The authors frame their discussion around the two principal classes of plant immune receptors. The first comprises pattern recognition receptors, cell-surface proteins that detect conserved microbial molecules such as bacterial flagellin, elongation factor Tu, and fungal chitin. Landmark structural studies, including the 2013 Science paper on the Arabidopsis FLS2–BAK1 complex activated by the flagellin epitope flg22, revealed how these receptors dimerize with co-receptors to initiate signaling. The second class consists of intracellular nucleotide-binding leucine-rich repeat receptors, or NLRs, which detect pathogen effectors delivered inside host cells. Together these two receptor families form a layered surveillance network that the review treats as an engineering platform rather than a fixed endowment.

A striking theme of the review is how structural biology has transformed receptor engineering from trial and error into rational design. Cryo-electron microscopy structures of activated NLR complexes, including the ZAR1 resistosome, the wheat Sr35 resistosome triggered by the AvrSr35 effector, and the hexameric NRC4 resistosome reported in 2024, showed that many NLRs function as oligomeric calcium-permeable channels. Because activation depends on defined conformational changes, ligand binding and effector recognition interfaces can now be mapped precisely, giving bioengineers specific residues to modify. Machine learning tools such as AlphaFold extend this capability by predicting receptor structures for which experimental structures are unavailable, enabling comparative modeling across large receptor families and the identification of candidate binding surfaces for targeted mutagenesis.

The review documents several concrete engineering successes at the cell-surface layer. Reverse engineering of FLS2, described in Nature Plants in 2025, revealed design principles that broaden recognition spectra against evading flg22 epitopes, while related work unlocked expanded flagellin perception through rational receptor engineering. Domain-swap approaches have a long pedigree here: chimeric receptors combining the extracellular domain of one receptor with the signaling domain of another, such as EFR–Cf-9 and CEBiP–Pi-d2 fusions, have produced enhanced responses to bacterial and fungal pathogens. Engineering of secreted protease co-receptors has converted divergent Rcr3 orthologs into functional immune components, and a 2026 Science study resolved how a damage-sensing receptor recognizes glycans, adding yet another recognition modality to the engineering toolbox.

At the intracellular layer, the review highlights strategies that exploit the modular architecture of NLRs. Many NLRs carry integrated domains that mimic effector targets, functioning as decoys or sensors; engineering these domains, as demonstrated for rice NLR pairs in eLife studies, can expand the profile of recognized effectors. Nanobody–NLR fusions reported in Science in 2023 conferred resistance by coupling synthetic binders to immune activation, effectively programming receptors against arbitrary molecules. Remodeling autoactive NLRs for broad-spectrum immunity, published in Nature in 2025, and a plug-in strategy for resistance engineering inspired by the potato NLRome, published in Nature in 2026, illustrate how both engineered and naturally evolved receptor modules can be recombined. Artificial evolution, from early work extending the spectrum of a potato virus resistance gene to stepwise evolution of the Sw-5b receptor against resistance-breaking tospovirus isolates, remains a complementary approach that does not require detailed structural knowledge.

Transfer of immune receptor genes across species boundaries emerges as one of the most immediately translatable strategies. The Arabidopsis EFR receptor, which recognizes bacterial elongation factor Tu, has been expressed in tomato, potato, rice, wheat, banana, sweet orange, apple, Medicago and citrus, in each case enhancing resistance to bacterial pathogens without disrupting beneficial symbioses in legumes. The rice Xa21 receptor has been deployed in banana and mandarin against Xanthomonas diseases. Interfamily transfer of NLRs has likewise matured: wheat stem rust genes Sr22, Sr33, Sr35 and Sr45 function in barley, and a 2025 Cell paper showed that co-transfer of sensor and helper NLR pairs extends receptor functionality between angiosperms, resolving a long-standing bottleneck in which transferred receptors lacked their required signaling partners.

The review is candid about the central trade-off that constrains all immune engineering: growth versus defense. Constitutive immune activation imposes fitness costs, and the literature on growth–defense trade-offs, surveyed in recent Cell Host & Microbe and Plant Biotechnology Journal commentaries, shows that breeders must balance resistance against yield. Several solutions are highlighted. Upstream open reading frames can tune receptor expression so that defense proteins accumulate only upon infection, an approach shown in Nature in 2017 to confer engineered resistance without fitness costs. Genome editing of susceptibility genes and promoters has produced broad-spectrum resistance in rice and wheat without growth penalties, and targeted protein degradation technologies are being applied to remove condensation-prone immune proteins that otherwise damage the endoplasmic reticulum.

Looking forward, the authors identify CRISPR-based genome editing and artificial intelligence as the technologies most likely to accelerate the field. CRISPR enables precise edits to receptor genes, promoter architecture, and susceptibility targets within elite cultivar backgrounds, bypassing the linkage drag of conventional introgression from wild relatives. AI-assisted protein design, exemplified by atomically accurate de novo antibody design with RFdiffusion reported in Nature in 2026, offers a template for designing synthetic recognition domains with programmable specificity. Machine learning resources such as the NLRexpress motif predictor suite and in silico prediction of NLR–effector interactions are already used to prioritize candidate receptors from the rapidly growing sequence databases generated by resistance gene enrichment sequencing and pan-genome studies.

The review closes with a sober assessment of the translational challenges that stand between laboratory success and agricultural impact. Stacking multiple receptors, as demonstrated with three late blight resistance genes in African highland potato and a five-transgene cassette against wheat rust, is essential for durability because pathogen populations evolve to overcome single genes, but stacking raises regulatory and intellectual property complexities. The authors argue that scalability, regulatory harmonization and equitable access must be addressed in parallel with the science, pointing to initiatives such as the Open Source Seed Initiative as models. By integrating mechanistic insight, structural design and deployment strategy, they contend, plant immune receptor engineering can deliver the environmentally sustainable crop production systems that rising pathogen pressure and a changing climate increasingly demand.

Subject of Research: Engineering of plant pattern recognition receptors and NLR immune receptors for broad-spectrum, durable crop disease resistance

Article Title: Plant immune receptor engineering

Article References: Wang, J., Li, Y., Hong, Y., & Liu, Y. (2026). Plant immune receptor engineering. Nature Reviews Bioengineering. https://doi.org/10.1038/s44222-026-00499-3

Image Credits: AI Generated

DOI: 10.1038/s44222-026-00499-3

Keywords: plant immunity, immune receptors, NLR proteins, pattern recognition receptors, crop biotechnology, resistosome, CRISPR genome editing, AlphaFold, protein engineering, disease resistance, food security, interfamily gene transfer