Transcriptomics and coexpression network profiling of the effects of levamisole hydrochloride on Bursaphelenchus xylophilus

Jie Chen,Xin Hao,Buyong Wang,Ling Ma

doi:10.1016/j.pestbp.2021.105019

Abstract

Bursaphelenchus xylophilus is one of the most dangerous forest pathogens in the world, causing devastating pine forest deaths with considerable economic losses. In this study, we investigated the B. xylophilus RNA sequence responses of two different concentrations of levamisole hydrochloride (LH). We observed that body-wall muscle twitching, paralysis and, ultimately, death. 2.5 mg/ml and 3.5 mg/ml LH have toxicological effects on B. xylophilus, with mortality increasing significantly with concentration (p < 0.05). RNA sequencing, differential gene expression analysis, and cluster analysis were performed, and 336, 384, 6 genes with significant variance in expression were identified. Gene Ontology annotation and Kyoto Encyclopedia of Genes and Genomes pathway analyses of the 12 intersecting genes revealed that these genes are mostly involved in metabolism of xenobiotics and have essential roles in drug sensitivity. Through the trend analysis of DEGs, it was divided into 8 modules, and the significant modules were selected to construct the co-expression network as the central genes of the drug metabolism-cytochrome P450 pathway (ko00982) and metabolism of xenobiotics by cytochrome P450 (ko00980). Eight highly related genes were identified, including cuticle collagen, cystathionine beta-synthase, endochitinase, pyruvate dehydrogenase E1 component subunit beta, aldehyde dehydrogenase, lipase, and zinc metalloproteinase. The expression levels of these genes were upregulated significantly at low concentrations and were significantly related to the resistance of B. xylophilus to LH. This study shows that B. xylophilus gene family expansions occurred in xenobiotic detoxification pathways through gene expression and potential horizontal correlated gene transfer with LH and helps to elucidate LH lethality and the evolutionary mechanisms underlying the adaptations of B. xylophilus to the environment. These results contributing to our understanding of B. xylophilus under LH and provide a data platform to providing a basis for its control.

Highlights

Bursaphelenchus xylophilus is one of the most dangerous forest pathogens in the world, resulting in the devastating death of pine forests and causing great economic losses and forest ecological damage to the affected areas
This study has shown that B. xylophilus gene family expansions occurred in xenobiotic detoxification pathways through the degree of genes expression and potential horizontal correlated gene transfer with levamisole hydrochloride (LH), and shed light on LH lethality and evolutionary mechanisms behind adaptations of B. xylophilus to the environment
These findings contribute in several ways to our understanding of B. xylophilus under LH and provide a basis for control of it

Summary

Introduction

Bursaphelenchus xylophilus is one of the most dangerous forest pathogens in the world, resulting in the devastating death of pine forests and causing great economic losses and forest ecological damage to the affected areas. When it was exported to Japan, South Korea, and China in East Asia with diseased trees, it caused devastating damage to the local pine ecosystem[2, 5, 6].The problem of B. xylophilus caused widespread concern. Avermectin injection is often used in South Korea to protect pine[10], but its high prices limit the feasibility of its widespread use. Chemical nematicidal agents, such as fosthiazate carbofuran[11, 12], are mostly broad-spectrum and non-specific. While controlling nematodes, they are very easy to harm non-harrowing organisms, including natural enemy insects, such as Scleroderma guani、Ichneumonidae. It is urgent to find specific, efficient, and cheap nematicidal agents

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