Plants use same chemical alarm system across populations, study finds
Two geographically distinct plant populations emit nearly identical chemical signals when attacked by insects, even though they evolved differently. The discovery suggests plants may share a universal pest-alert system—a finding that could inform crop breeding programs and biological pest management strategies in agriculture.
Originaltitel: Conserved herbivore-induced volatile signalling despite divergent VOC–life-history associations in two locally adapted <i>Arabidopsis thaliana</i> populations
**Växter signalerar herbivore-hot via flyktiga ämnen – även mellan lokalt olika populationer** Växter avger flyktiga organiska ämnen (VOC) när insekter attackerar dem, och dessa kemiska signaler varnar omkringliggande växter. En forskargrupp vid Basque Centre for Climate Change undersökte om denna försvarsmekanism skiljer sig mellan två lokalt anpassade Arabidopsis-populationer från Iberien. Trots att populationerna hade mycket olika livscykler och genetisk struktur, behöll båda en liknande VOC-profil vid herbivorbeskattning. Det kritiska resultatet: mottagarväxterna från båda populationerna visade reducerad insektskada efter exponering för herbivorbeskattade plantor, vilket tyder på en bevarad signalmekanisme. Kopplingen mellan VOC-egenskaper och reproduktionsförmåga varierade dock mellan populationerna. Studien från Basque Centre for Climate Change, Stockholm University och Neuchâtel universitet visar att växtförsvaret genom kemisk signalering är robust, medan integrationen mellan försvar och tillväxt är populationspecifik. För växtförädling relevanta slutsatser väntas framöver.
Volatile organic compounds (VOCs) mediate plant–plant signalling and may contribute to phenotypic differentiation among populations. However, the extent to which VOC-mediated signalling varies among locally adapted populations, and how VOC traits relate to major fitness-related traits, remain poorly understood. We conducted a greenhouse experiment using two genetically and phenologically divergent Iberian populations of Arabidopsis thaliana . Plants were exposed to herbivory by Spodoptera exigua , after which we quantified herbivore-induced VOC emissions, VOC-mediated signalling effects on neighbouring conspecifics, and relationships between VOC traits, flowering time, and seed germination. Herbivory altered VOC composition, but overall VOC profiles remained broadly similar between populations despite strong divergence in life-history strategies, constitutive resistance to herbivory, and genetic structure. In contrast, correlations between VOC traits and fitness-related traits differed between populations and herbivory treatments. Nevertheless, receiver plants from both populations exhibited reduced herbivore damage after exposure to herbivore-induced emitters, indicating conserved VOC-mediated signalling. Our results suggest that herbivore-induced volatile signalling may represent a relatively conserved component of plant defence across locally adapted populations. In contrast, relationships between VOC traits and life-history variation may reflect population-specific integration of defence and fitness-related traits.