Objective  Effects of pine wood nematode (PWN) invasion on Pinus massoniana were quantified based on multiomics.

  Method  Among 4-year-old Masson pine plants, a treatment, PWN(+), by inoculating 5 000 Bursaphelenchus xylophilus and a control, PWN(−), with the injection of sterile distilled water into the tree trunks were subjected to a 14 d post-inoculation followed by a quantified study including phenomics, transcriptome, microbiome, and metabolome.

  Result   The pine trees in the PWN(+) group significantly increased over control on the contents of the reactive oxygen species (ROS) by 3.2-fold and hydrogen peroxide (H₂O₂) by 1.7-fold (P＜0.05), on the expressions of c60547.graph_c0 and c82953.graph_c0 in the unigenes encoding stress responsive pathways (P＜0.05), as well as on the expressions of c64867.graph_c0 and c68789.graph_c0 in the terpenoid biosynthesis pathways; and significantly lower on the c81022.graph_c0 in syncytium formation (P＜0.05) and the microbial diversity (P＜0.05). Hypocreales was the dominant order of microorganisms in the PWN(+) group. The functional annotations and abundance information from the KEGG database were mainly related to the replication and repair pathways, DNA replication pathway (PATH:ko03030), and DNA replication protein pathway (BR:ko03032). There were 365 upregulated and 351 downregulated differentially regulated metabolites in the metabolome. Metabolites like phloretin, ursodiol, and carbenpenicillin were notably enriched in the ABC transporters pathway, arachidonic acid metabolism, flavonoid biosynthesis, and glycerophospholipid metabolism in the PWN-infected pine wood to resist the invasion.

  Conclusion  After PWN was inoculated in Masson pine, the host responded with a series of complex defensive reactions initiated by various mechanisms. Through multiomics, some such interactions between the species were unveiled providing clues for combating forestry declination by the infestation.