Pine wilt disease (PWD) is a worldwide forest disease caused by pine wood nematode (PWN). In this article, we investigated the composition, organization, correlation, and function of the endophytic microbial community in Pinus massoniana field with and without PWN. Samples were taken from branches, upper, middle, and lower trunks, as well as soil, from both healthy and infected trees. The results showed that the fungal diversity of healthy pines is around 1.1 times that of infected pines, while the bacterial diversity is about 0.75 times that of infected pines at the OTUs level. An increase of the abundance of pathogenic fungus such as Saitozyma, Graphilbum, Diplodia, Candida, Pseudoxanthomonas, Dyella and Pantoea was witnessed in infected pines according to the result of LEfSe. Furthermore, Ophiostoma and saprophytic fungus such as Entomocorticium, ganoderma, tomentella, entomocorticium were exclusively prominent in infected pines, which were substantially and highly connected with other species (p < 0.05), indicating the trees’ vulnerability and making the wood blue. In healthy pines, the top three functional guilds are parasites, plant pathogens, and saprotrophs. Parasites (36.52%) are primarily found in the branches, plant pathogens (29.12%) are primarily found in the lower trunk, and saprotrophs (67.88%) are primarily found in the upper trunk of disease trees. Pines’ immunity is being eroded due to an increase in the quantity and types of diseases. PICRUSt2 research revealed that NADH or NADPH, as well as carbon-nitrogen bonds, were more abundant in healthy pines, but acid anhydrides and transferring phosphorus-containing groups were more abundant in infected pines. The shift in resin secretion lowers the tree’s potential and encourages pine wilt and mortality. In total, PWN may have disrupted the microbiological ecology and worked with the community to hasten the demise of pines.

From May to October 2018, a total of 38 diseased Pinus sylvestris were found among 120 samples, with a field incidence rate up to 30%. The disease was found on needles and twigs of P. sylvestris. I...

Pinewood nematode (PWN; Bursaphelenchus xylophilus) is a devastating invasive species that is expanding into colder regions. Here, we investigated the molecular mechanisms underlying low‐temperature resistance of PWN. We identified differentially expressed genes enriched under low temperature in previously published transcriptome data using the Kyoto Encyclopedia of Genes and Genomes. Quantitative real‐time PCR was used to further validate the transcript level changes of three known cytochrome P450 genes under low temperature. RNA interference was used to validate the low‐temperature resistance function of three cytochrome P450 genes from PWN. We report that differentially expressed genes were significantly enriched in two cytochrome P450‐related pathways under low‐temperature treatment. Heatmap visualization of transcript levels of cytochrome P450‐related genes revealed widely different transcript patterns between PWNs treated under low and regular temperatures. Transcript levels of three cytochrome P450 genes from PWNs were elevated at low temperature, and knockdown of these genes decreased the survival rates of PWNs under low temperature. In summary, these findings suggest that cytochrome P450 metabolism plays a critical role in the low‐temperature resistance mechanism of PWN.