Deciphering organ‐specific chemical changes following insect herbivory in <i>Populus nigra</i> using comparative metabolomics

This study explores the chemical diversity of plant metabolites in different organs of black poplar (Populus nigra), a tree species of considerable ecological and economic importance, to broaden our knowledge of organs other than leaves, especially with regard to herbivore-induced changes. Targeted and non-targeted metabolite analyses were used to investigate the defence responses of black poplar organs, including leaves, wood, bark, and roots, to aboveground feeding damage by caterpillars of the generalist herbivore Lymantria dispar. The research revealed that metabolic responses to herbivory are organ-specific, with a large increase in unique features upon insect damage. Herbivory led to more significant changes in central (primary) metabolites than the targeted specialized (secondary) metabolites measured. The study concludes that understanding the complexity of organ-specific metabolism in black poplar can be very useful for investigating plant-herbivore interactions in this tree species.