A team led by Ken Shirasu at the RIKEN Center for Sustainable Resource Science (CSRS) in Japan has uncovered an ancient immune receptor that could help plants defend themselves against tens of thousands of pathogens. Named SCORE (Selective COld shock protein Receptor), the protein detects “cold-shock” proteins — molecules found in more than 85% of known bacteria, as well as in fungi and insects.
In findings published Sept. 4 in Science, the researchers showed that swapping out sections of SCORE can change which cold-shock protein it recognizes, offering a potential strategy to engineer synthetic receptors that give crops and trees new defenses against diverse diseases.
Pathogen infections in flowering plants such as rice, wheat, olive trees, and bamboo often reduce size and yield. Plants naturally defend themselves through receptor proteins that detect pathogen molecules and trigger immune responses — but no single receptor recognizes every current or future threat. While receptors from one plant family (e.g., cabbages and broccoli) can sometimes be transferred to another (e.g., tomatoes and potatoes), the challenge is that of the hundreds of thousands of possible receptor–microbe pairs, fewer than ten have been identified so far, mostly in well-studied model species.
To address this gap, Shirasu’s group began with over 1,300 receptors from 350 plant genomes and eventually identified a previously unknown receptor in pomelo, a common citrus plant. They discovered that SCORE responds to some, but not all, cold-shock proteins by recognizing a short sequence of 15 amino acids, dubbed csp15. Changing certain amino acids within csp15 altered which cold-shock proteins SCORE could detect, according to a press release.
Further analysis revealed that nearly all pathogens except viruses produce at least one type of cold-shock protein. Most of the amino acids in csp15 are conserved, but positions 6, 7, 14, and 15 vary widely — critical sites that influence recognition. The team also identified more than 60 variations of SCORE across plant lineages, tracing its origins back to the last common ancestor of all flowering plants. This suggests that many crops already carry versions of this receptor, which could be harnessed to build broader and more durable disease resistance.
“This was a particularly unexpected finding,” explains co-author Yasuhiro Kadota. “The extensive natural variation in CSP recognition across SCORE orthologs from different plant lineages suggests that this kind of immune receptor has repeatedly evolved to fine-tune pathogen detection through specific amino acid substitutions.”
Analysis of the different SCORE variants revealed specific positions in the amino acid sequence that change across plant lineages. By examining these variations and their charge, the researchers could predict which csp15 sequences each SCORE would recognize.
The next step was to test this predictive power by engineering new versions of pomelo SCORE. By swapping out key sections, they created receptors able to detect pathogens that the natural pomelo SCORE does not. For instance, while the original receptor failed to recognize cold-shock proteins from Ralstonia, Erwinia, or Xanthomonas bacteria, the synthetic version successfully responded to all three.
“In the short term,” says Shirasu, “this study provides a new framework for identifying and engineering immune receptors from non-model plants, especially long-lived perennials, for which genetic tools are limited.”
Added first author Bruno Pok Man Ngou, “Our next objective is to introduce engineered SCORE variants into economically important crop species in efforts to confer broad-spectrum resistance against pathogens and pests. This offers a sustainable approach to enhancing disease and pest resilience in agriculture and contributes to global food security.”