Jasmonic acid and salicylic acid interact to determine spatial regulation of gene expression responses in potato leaf to herbivory by Colorado potato beetle and mechanical wounding

Abstract

We investigated the spatial dynamics of potato (Solanum tuberosum) responses to herbivory and mechanical wounding. We first followed the spatiotemporal response of jasmonic acid (JA) signaling, known to be involved in the response. We generated two potato sensor lines: a JAZ degradation sensor and a downstream multicystatin (MC) transcriptional reporter. Both sensors revealed concentric, locally restricted responses on wounded leaves. Notably, JA-dependent gene expression was absent in cells immediately adjacent to the wound, whereas JAZ degradation spread continuously outward from the wound site. This pattern occurred after both herbivore attack and mechanical injury by the needle. To probe the mechanism, a salicylic acid (SA) reporter showed SA accumulation near the wound. Introducing the MC reporter into SA-depleted NahG plants produced a uniform spread of MC expression, confirming that SA attenuates the JA response in proximal cells. Together, these results show that a locally distinct, spatiotemporal SA–JA crosstalk shapes wound responses in potato, extending principles known from pathogen–plant interactions to herbivory and mechanical damage.