Impact of the pinewood nematode on naturally-emitted volatiles and scCO2 extracts from Pinus pinaster branches: a comparison with P. pinea

Abstract

In Portugal,the pinewood nematode (PWN), Bursaphelenchus xylophilus, has been affecting Pinus pinaster, leading to economic and ecological losses, while P. pinea is a less susceptible species. The main goal of this study was to assess volatile composition of PWN-infected P. pinaster, and both non-infected P. pinaster and P. pinea branches, by using supercritical carbon dioxide extraction compared with solidphase microextraction (SPME). Volatile profile was associated to nematodes number, which was related to moisture content. Extracts effects on acetylcholinesterase (AChE) inhibitory activity, and in vitro PWNmortality were analyzed. Limonene was the main volatile naturally-emitted by P. pinea and by some PWN-infected P. pinaster samples. Abietadiene was identified in some PWN-infected P. pinaster extracts, which may be due to a tree defensive response. Supercritical CO2 extracted ∼5–20 heavier compounds than those identified by the SPME-GC/MS technique. Extracts revealed AChE inhibition, corresponding to a possible insecticidal/nematicidal effect. However, no PWN-mortality was found.