Manipulating stomatal aperture by silencing StSLAC1 affects potato plant-herbivore-parasitoid tritrophic interactions under drought stress

The effects of drought stress on stomatal opening dynamics, plant volatile organic compound (VOC) emissions and plant-insect interactions have been well-documented individually, but how they interact mechanistically remains poorly studied. Here, we studied how drought-triggered stomatal closure affects VOC emission and plant-trophic interactions by combining RNAi silencing, molecular biological and chemical analyses (GC-MS) of a potato-tuber moth-egg parasitoid tritrophic system. Drought stress attenuated stomatal apertures and VOC emissions, which made the potato (Solanum tuberosum L.) plants more attractive to the herbivore but less attractive to the parasitoid. Stomatal aperture manipulations through StSLAC1 gene knockdown and chemical treatments (ABA and 5-aminolevulinic acid) consistently affected drought-triggered VOC emissions and plant-herbivore-parasitoid interactions, supporting aperture-dependent VOC emission. RNA-Seq analysis revealed that drought stress did not transcriptionally inhibit VOC biosynthesis. Collectively, our findings are consistent with the stomatal regulation of plant-insect interactions through the modulation of VOC emissions under drought stress. This highlights the intricate interplay between stomatal dynamics, VOC emission and plant-insect interactions.