In silico screening of agonist and antagonist natural compounds from reported essential oils against Bursaphelenchus xylophilus

Invasive pathologies have become an increasing threat to forestry and related industries. Pine wilt disease (PWD) destroys tree vascular tissues and resin canals inducing pine needle chlorosis and shoot wilting. It was introduced in Europe in 1999, probably through imported wood products from Asian countries. Despite the numerous control strategies, its causal agent, the pinewood nematode (PWN), Bursaphelenchus xylophilus, continues to spread at an alarming rate. Pest control based on trunk injection of nematicidal compounds remains the most effective and reliable containment strategy. Nevertheless, large spectrum nematicides can be dangerous to human health and the environment. Highly active essential oils (EOs) were reported to reach higher in vitro efficiencies than common use nematicides. EOs can be composed of a wide array of secondary metabolites, in various proportions, with distinct anti-PWN activities. The present work screened the existing bibliography on detailed chemical composition and activity of the EOs used against the PWN. The abundance of each EO component was correlated with the respective EO anti-PWN activity. Monoterpenoids dominated the structures with agonist or antagonist properties. Compounds showing transversal positive correlations were mainly alcohols and aldehydes while those showing negative correlations were hydrocarbons, ethers and ketones. Citronellol, a monoterpenic alcohol component of nine reported EOs, showed the best positive dose-response correlation, while the best negative correlation was identified for 1,8-cineole, a monoterpenic ether present in over 50 EOs. Using this transversal approach in EO nematicidal activity studies allows pinpointing highly active EO components and respective interactions with the PWN.