Stage-specific transcriptome of Bursaphelenchus xylophilus reveals temporal regulation of effector genes and roles of the dauer-like stages in the lifecycle

Abstract

The pine wood nematode Bursaphelenchus xylophilus is the causal agent of pine wilt disease, one of the most devastating forest diseases in East Asian and West European countries. The lifecycle of B. xylophilus includes four propagative larval stages and gonochoristic adults which are involved in the pathogenicity, and two stages of dispersal larvae involved in the spread of the disease. To elucidate the ecological roles of each developmental stage in the pathogenic life cycle, we performed a comprehensive transcriptome analysis using RNA-seq generated from all developmental stages of B. xylophilus and compared transcriptomes between stages. We found more than 9000 genes are differentially expressed in at least one stage of the life cycle including genes involved in general nematode biology such as reproduction and moulting but also effector genes likely to be involved in parasitism. The dispersal-stage transcriptome revealed its analogy to C. elegans dauer and the distinct roles of the two larval stages from each other regarding survival and transmission. This study provides important insights and resources to understand B. xylophilus parasitic biology.

Molecular variation among virulent and avirulent strains of the quarantine nematode Bursaphelenchus xylophilus

“…xylophilus, each gene in the expanded peptidase family has distinct role. This is a clear example of gene family evolution by gene duplication and functional divergence (Tanaka et al 2019). Nematode peptidases, which hydrolyse polypeptides or proteins, participate in a wide range of molecular, biological, and cellular processes, such as a digestion of host proteins, moulting and embryonic development of the egg (Tanaka et al 2019).…”

“…This is a clear example of gene family evolution by gene duplication and functional divergence (Tanaka et al 2019). Nematode peptidases, which hydrolyse polypeptides or proteins, participate in a wide range of molecular, biological, and cellular processes, such as a digestion of host proteins, moulting and embryonic development of the egg (Tanaka et al 2019). The genome sequence of B. xylophilus revealed a large number of predicted peptidase genes (808 peptidase genes), representing the highest gene number among characterised nematode genomes.…”

Transcriptomic profiling of effects of emamectin benzoate on the pine wood nematode Bursaphelenchus xylophilus

“…In China, PWD has killed billions of pine trees since its introduction in 1982 resulting in approximately 5 million m 3 of annual wood loss . PWN reproduces rapidly in host plants, developing to the adult stage through four juvenile stages (J1–J4; nota bene: J1 molts to J2 inside egg) within less than a week . It has high fecundity with 90–100 eggs laid per female and can be highly concentrated with millions of PWN in host plants .…”

“…PWN reproduces rapidly in host plants, developing to the adult stage through four juvenile stages (J1–J4; nota bene: J1 molts to J2 inside egg) within less than a week . It has high fecundity with 90–100 eggs laid per female and can be highly concentrated with millions of PWN in host plants . PWN can secret numerous pathogenesis‐related enzymes including cell‐wall‐degrading cellulases and pectate lyases, facilitating the penetration and migration through the host cells .…”

Nearly Complete Genome Assembly of the Pinewood Nematode Bursaphelenchus xylophilus Strain Ka4C1

“…The final assembly was 78.3 Mbp long, which is 3.7 and 2.4 Mbp bigger than the previous v1.2 ( 2 ) and v2.0 ( 10 ) assemblies, respectively, and showed slightly better CEGMA v2.5 ( 11 ) completeness values ( Table 1 ). However, a G+C content of 40.4% was consistent for all assemblies.…”