Metabolomic and volatile profiling reveals defence-related effects of IbPep1 in sweet potato cell culture

Damage-associated molecular patterns (DAMPs), which are recognised by specific plant receptors and trigger downstream signaling cascades that control various functions within plants, have recently emerged as key regulators of plant physiology. Over the years, researchers have identified novel peptides like systemin and HypSys to play crucial roles in defense, and their thorough characterisation has highlighted their biotechnological potential. Plants, being repositories of such compounds, encourage researchers to explore this seemingly limitless potential. Thus, in this study, we investigated IbPep1, an elicitor peptide identified in sweet potato (Ipomoea batatas), to assess its effects on plant metabolism and its potential role in defence responses. We generated a sweet potato cell suspension culture and analysed its response to the recently discovered plant elicitor peptide, IbPep1 in comparison with other known elicitors, including flg22. In contrast to the latter, IbPep1 did not elicit a significant ROS burst but at higher concentration peptide treatment significantly increased JA-Ile concentration. The levels of free amino acids remained unaffected. Strikingly, untargeted metabolomics revealed that IbPep1 mostly affected the shikimate and phenylpropanoid pathways and volatiles’ analysis showed a stimulated emission of sesquiterpenes by IbPep. The structural diversity and incompatibility between families make the study of Peps challenging. However, due to their widespread presence in angiosperms, they are attractive targets for biotechnological applications. In our study, we compared the effects of IbPep1 with those of known elicitors and discovered that its regulatory functions share some similarities with signaling peptides from other plant families, while also revealing novel effects such as the regulation of volatile compounds. These results shed light on the signaling activity of IbPep1 and its impact on specialised metabolic pathways, emphasising its potential role in plant defence and metabolic regulation.