Specifically Expressed Genes of the Nematode Bursaphelenchus Xylophilus Involved with Early Interactions with Pine Trees

Abstract

As the causal agent of pine wilt disease (PWD), the pine wood nematode (PWN), Bursaphelenchus xylophilus, causes huge economic losses by devastating pine forests worldwide. However, the pathogenesis-related genes of B. xylophilus are not well characterized. Thus, DNA microarrays were used to investigate differential gene expression in PWN where Pinus thunbergii was inoculated with nematodes, compared with those cultured on Botrytis cinerea. The microarrays comprised 31121 probes, 1310 (4.2%) of which were differentially regulated (changes of >2-fold, P < 0.01) in the two growth conditions. Of these 1310 genes, 633 genes were upregulated, whereas 677 genes were downregulated. Gene Ontology (GO) categories were assigned to the classes Cellular Component, Molecular Function, and Biological Process. The comparative gene expression analysis showed that a large number of the pathogenesis-related genes of B. xylophilus, such as pectate lyase genes, cytochrome P450s, UGTs, and ABC transporter genes, were highly expressed when B. xylophilus infected P. thunbergii. Annotation analysis indicated that these genes contributed to cell wall degradation, detoxification, and the reproduction process. The microarray results were validated using quantitative RT-PCR (qRT-PCR). The microarray data confirmed the specific expression of B. xylophilus genes during infection of P. thunbergii, which provides basic information that facilitates a better understanding of the molecular mechanism of PWD.

Non‐specific transient mutualism between the plant parasitic nematode, Bursaphelenchus xylophilus, and the opportunistic bacterium Serratia quinivorans BXF1, a plant‐growth promoting pine endophyte with antagonistic effects

“…S2). Qiu et al (2013) showed that the expression of Bxcht-1 was downregulated dramatically when B. xylophilus was used to inoculate Pinus thunbergii compared with the PWN culture on B. cinerea, suggesting that this chitinase gene is, in fact, responsible for chitin degradation when the nematode feeds on fungi. This result suggests that in the presence of bacteria the PWN does not express the Bxcht-1 gene, thus, supporting our hypothesis.…”

Identification and characterization of parasitism genes from the pinewood nematode Bursaphelenchus xylophilus reveals a multilayered detoxification strategy

“…For example, one study has used proteomics analysis of secreted proteins collected from nematodes stimulated with pine extracts and identified cell wall-degrading enzymes, detoxification enzymes and peptidases amongst the secreted proteins (Shinya et al, 2013). In an alternative approach, microarray analysis has been used to identify secreted proteins up-regulated during infection (Qiu et al, 2013).…”

Transcriptional and morphological changes in the transition from mycetophagous to phytophagous phase in the plant‐parasitic nematode Bursaphelenchus xylophilus

“…Indeed, the expression of genes encoding antioxidant proteins may be a response to host‐derived ROS. These genes were identified here and were also expressed in B. xylophilus 7 days after infection in pine trees (Qiu et al ., ). Bursaphelenchus xylophilus is known to produce surface coat proteins to help protect itself from ROS (Shinya et al ., ).…”