Genetic characteristics of Bursaphelenchus xylophilus third-stage dispersal juveniles

Qiaoli Chen,Feng Wang,Ruizhi Zhang,Danlei Li

doi:10.1038/s41598-021-82343-9

Abstract

The third-stage dispersal juvenile (DJ3) of pinewood nematode (PWN) is highly associated with low-temperature survival and spread of the nematode. Oil-Red-O staining showed that its lipid content was significantly higher compared with other PWN stages. Weighted gene coexpression network analysis identified that genes in the pink module were highly related to DJ3 induced in the laboratory (DJ3-lab). These genes were arranged according to their gene significance (GS) to DJ3-lab. Of the top 30 genes with the highest GS, seven were found to be highly homologous to the cysteine protease family cathepsin 1 (CATH1). The top 30 genes with the highest weight value to each of the seven genes in the pink module were selected, and finally 35 genes were obtained. Between these seven CATH1 homologous genes and their 35 highly related genes, 15 were related to fat metabolism or autophagy. These autophagy-related genes were also found to be highly correlated with other genes in the pink module, suggesting that autophagy might be involved in the mechanism of longevity in DJ3 and the formation of DJ3 by regulating genes related to fat metabolism.

Highlights

The third-stage dispersal juvenile (DJ3) of pinewood nematode (PWN) is highly associated with lowtemperature survival and spread of the nematode
DJ3 is the prerequisite of DJ4, which can be transmitted with Monochamus beetles
Oil-Red-O staining of the DJ3 induced in the laboratory (DJ3-lab) and DJ3-field PWNs showed obviously more fat masses than other stages (Fig. 1O–Q), this characteristic can be used for the morphological identification of DJ3 (Fig. 1R)

Summary

Introduction

The third-stage dispersal juvenile (DJ3) of pinewood nematode (PWN) is highly associated with lowtemperature survival and spread of the nematode. The top 30 genes with the highest weight value to each of the seven genes in the pink module were selected, and 35 genes were obtained Between these seven CATH1 homologous genes and their 35 highly related genes, 15 were related to fat metabolism or autophagy. The pinewood nematode (PWN), Bursaphelenchus xylophilus, is a migratory endoparasitic species that causes pine wilt disease (PWD), which is one of the most damaging diseases that affect conifer forests ( Pinus spp.)[1,2,3]. Blocking the formation of DJ3 blocks the formation of DJ4, preventing the nematodes from dispersing with Monochamus beetles and reducing the spread of PWD to healthy pine forests. Unlike DJ4, which have unique morphological features[28], DJ3 are not morphologically distinct from third-stage propagative juveniles (J3), except that the body

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