Gall-inducing Dasineura sp. remodels the lipid profile and enhances the phytotoxic potential of Peumus boldus stems

In several gall systems induced by dipterans, lipids accumulate in specialized tissues, contributing to larval nutrition and plant defense. Peumus boldus Molina, Monimiaceae, a native Chilean tree known for producing bioactive compounds with phytotoxic properties, offers a unique model to explore how galling by Dasineura sp. (Diptera: Cecidomyiidae) affects host lipid metabolism and allelopathic potential. However, the specific impact of Dasineura sp. on the lipid composition of P. boldus stems remains unexplored, particularly regarding the phytotoxicity of this species. To address this gap, we characterized the lipid composition of galled and nongalled stems of P. boldus and evaluated their phytotoxic effects. Lipids were extracted from galled and nongalled stems using petroleum ether in a Soxhlet apparatus and analyzed by gas chromatography-mass spectrometry. Histochemical staining was used to localize lipid accumulation, and phytotoxicity was assessed using Portulaca oleracea L. as a target species. Galls presented altered lipid profiles and accumulation patterns, with lipids concentrated in nutritive tissue and the suber, cortex, and cortical parenchyma. Galled stems presented relatively high levels of fatty acids and oxygenated sesquiterpenes. Extracts from galled tissues significantly inhibited P. oleracea seedling growth, indicating increased phytotoxicity. These findings suggest that galling insects redirect lipid biosynthesis toward defense-related compounds, enhancing the allelopathic potential of host tissues.