A Reference Genome of Provides New Resources for Revealing Its Displacement by Pinewood Nematode.

The , which was highly similar with in terms of morphological characteristics and biological properties-but had weaker pathogenicity to forests-was a native species often displaced by when occupying the same niche. Since the draft genome of the invasive has been published, the absence of a reference genome of still prevents us from understanding the molecular evidences behind competitive displacement. In this study, we employed Single Molecule, Real-Time (SMRT) sequencing and a Hi-C scaffolding approach to yield a near chromosome-level assembly of , including six pseudo-chromosomes. The assembly size is 73 Mb, with scaffold N50 of 11.50 Mb and contig N50 of 1.48 Mb. Comparative genomics results showed high similarity between and . However, the losing of orphan genes and species-specific orthologous genes in may indicate weaker adaptability to the environment. The gene family contractions of GPCRs (G Protein-Coupled Receptors) and cellulases in may jointly contribute to its displacement by . Overall, we introduced a valuable genomic resource for molecular and evolutionary studies of , especially for studying the competitive displacement by the pinewood nematode, which could help us control the pathogenicity of pine wilt diseases.