Transcriptomic and Coexpression Network Analyses Revealed Pine Chalcone Synthase Genes Associated with Pine Wood Nematode Infection.

Qiaoli Chen,Danlei Li,Feng Wang,Ruizhi Zhang

doi:10.3390/ijms222011195

Qiaoli Chen, Danlei Li + Show 2 more

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https://doi.org/10.3390/ijms222011195

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Abstract

Pine wood nematode (PWN) causes serious diseases in conifers, especially pine species. To investigate the transcriptomic profiles of genes involved in pine-PWN interactions, two different pine species, namely, Pinus thunbergii and P. massoniana, were selected for this study. Weighted gene coexpression network analysis (WGCNA) was used to determine the relationship between changes in gene expression and the PWN population after PWN infection. PWN infection negatively affects the expression of most genes in pine trees, including plant defense-related genes such as genes related to plant hormone signal transduction, plant-pathogen interactions, and the MAPK signaling pathway in plants. However, the expression of chalcone synthase genes and their related genes were proportional to the changes in nematode populations, and chalcone synthase genes were dominant within the coexpression module enriched by genes highly correlated with the nematode population. Many genes that were closely related to chalcone synthase genes in the module were related to flavonoid biosynthesis, flavone and flavonol biosynthesis, and phenylpropanoid biosynthesis. Pine trees could actively adjust their defense strategies in response to changes in the number of invasive PWNs, but the sustained expression of chalcone synthase genes should play an important role in the inhibition of PWN infection.

Highlights

Pine wood nematode (Bursaphelenchus xylophilus, PWN) causes pine wilt disease (PWD), mainly resulting in susceptible conifers, in particular Pinus spp., to wilt rapidly and die [1]
The expression of many chalcone synthase genes and their related genes continued to increase after PWN infection, and the changes in the expression of these genes were proportional to the changes in nematode populations. These results suggested that the expression of chalcone synthase genes and their related genes plays an important role in the resistance of pine trees to PWN infection
We found that chalcone synthase genes were dominant within the module enriched by genes highly correlated with nematode populations

Summary

Introduction

Pine wood nematode (Bursaphelenchus xylophilus, PWN) causes pine wilt disease (PWD), mainly resulting in susceptible conifers, in particular Pinus spp., to wilt rapidly and die [1]. PWN requires an insect vector for local dispersal and infection [2]. The nematode can be transmitted when adult insects feed on the phloem of young twigs on healthy trees for sexual maturation [3,4] or during female oviposition into dying trees or cutting waste [5,6]. Once a PWN enters a tree, it can migrate through cortical and xylem axial and radial resin canals in pine stems and feed on plant tissues, which causes a series of physiological and biochemical changes, leading to water deficiency and tree mortality [1,7,8].

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