1. 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 woundingValentina Levak, Tjaša Mahkovec Povalej, Karmen Pogačar, Katja Stare, Maja Zagorščak, Tim Hawkins, Joanne Robson, David Dobnik, Tjaša Lukan, Kristina Gruden, 2025, original scientific article 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, JAdependent 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.
Keywords: Colorado potato beetle, herbivore, hormonal crosstalk, jasmonic acid, potato, salicylic acid, wounding
Published in DiRROS: 28.01.2026; Views: 636; Downloads: 688
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2. Ethylene signaling is essential for mycorrhiza-induced resistance against chewing herbivores in tomatoJavier Lidoy, Javier Rivero, Živa Ramšak, Marko Petek, Maja Križnik, Victor Flors, Juan A Lopez-Raez, Ainhoa Martinez-Medina, Kristina Gruden, Maria J Pozo, 2025, original scientific article Abstract: Arbuscular mycorrhizal (AM) symbiosis can prime plant defenses, leading to mycorrhiza-induced resistance (MIR) against different attackers, including insect herbivores. Still, our knowledge of the complex molecular regulation leading to MIR is very limited. Here, we showed that the AM fungus Funneliformis mosseae protects tomato plants against two different chewing herbivores, Spodoptera exigua and Manduca sexta. We explored the underlying molecular mechanism through genome-wide transcriptional profiling, bioinformatics network analyses, and functional bioassays. Herbivore-triggered jasmonate (JA)-regulated defenses were primed in leaves of mycorrhizal plants. Likewise, ethylene (ET) biosynthesis and signaling were also higher in leaves of mycorrhizal plants both before and after herbivory. We hypothesized that fine-tuned ET signaling is required for the primed defense response leading to MIR. ET is a complex regulator of plant responses to stress and is generally considered a negative regulator of plant defenses against herbivory. However, ET-deficient or insensitive lines did not show AM-primed JA biosynthesis or defense response, and were unable to develop MIR against any of the herbivores. Thus, we demonstrate that hormone crosstalk is central to the priming of plant immunity by beneficial microbes, with ET fine-tuning being essential for the primed JA biosynthesis and boosted defenses leading to MIR in tomato.
Keywords: chewing herbivores, defense priming, ethylene, hormonal crosstalk, jasmonate, mycorrhiza-induced resistance (MIR)
Published in DiRROS: 10.04.2025; Views: 1313; Downloads: 1352
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