Identification of a damage-associated molecular pattern (DAMP) receptor and its cognate peptide ligand in sweet potato (Ipomoea batatas)

Sweet potato (Ipomoea batatas) is an important tuber crop, but also target of numerous insect pests. Intriguingly, the abundant storage protein in tubers, sporamin, has intrinsic trypsin protease inhibitory activity. In leaves, sporamin is induced by wounding or a volatile homoterpene and enhances insect resistance. While the signalling pathway leading to sporamin synthesis is partially established, the initial event, perception of a stress-related signal is still unknown. Here, we identified an IbLRR-RK1 that is induced upon wounding and herbivory, and related to peptide-elicitor receptors (PEPRs) from tomato and Arabidopsis. We also identified a gene encoding a precursor protein comprising a peptide ligand (IbPep1) for IbLRR-RK1. IbPep1 represents a distinct signal in sweet potato, which might work in a complementary and/or parallel pathway to the previously described hydroxyproline-rich systemin (HypSys) peptides to strengthen insect resistance. Notably, an interfamily compatibility in the Pep/PEPR system from Convolvulaceae and Solanaceae was identified.

Automated summary

Sweet potato is an important crop that is often attacked by insect pests. Researchers have discovered that a storage protein called sporamin, which is abundant in the tubers, has trypsin protease inhibitory activity. This protein is induced by wounds or certain compounds, enhancing the plant's resistance to insects. The study also identified a gene called IbLRR-RK1, which is related to peptide-elicitor receptors found in tomato and Arabidopsis. Additionally, a peptide ligand called IbPep1 was found, which plays a role in strengthening insect resistance in sweet potato.