Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, China.
Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing Forestry University, Nanjing, China.
Pest Manag Sci. 2020 Aug;76(8):2755-2767. doi: 10.1002/ps.5823. Epub 2020 Apr 2.
Autophagy plays an important role in eukaryotes. We investigated its role in the pine wood nematode (PWN), Bursaphelenchus xylophilus, the causative agent of pine wilt disease (PWD), to find promising control strategies against PWD.
We analysed the expression levels of PtRBOH1 and PtRBOH2, which regulate reactive oxygen species (ROS) metabolism, in Pinus thunbergii and the expression of three autophagy genes, BxATG5, BxATG9 and BxATG16, in PWN by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and measured the content of H O , the main product of ROS metabolism, in pine stem. There was a correlation between the expression of autophagy genes in PWN and pine ROS metabolism during early infection. We also found that oxidative stress induces autophagy in PWN according to qRT-PCR, transmission electron microscopy and Western blot analyses. Inhibition of autophagy by 3-methyladenine or silencing of the autophagy genes BxATG9 and BxATG16 in PWN showed that autophagy is essential for feeding, fecundity, egg hatching and survival of PWN under oxidative stress, confirming the importance of autophagy in the antioxidant defences of PWN. Similarly, we demonstrated that autophagy contributes to the virulence of PWN. Moreover, PWN likely ameliorates oxidative damage by enhancing the activities of the peroxidase and catalase antioxidant pathways when autophagy is inhibited.
Autophagy contributes to resistance to the oxidative stress induced by pine ROS metabolism, thus promoting infection by PWN. Our findings clarify the defence mechanisms of PWN and the pathogenesis of PWD, and provide promising hints for control of PWD by blocking autophagy. © 2020 Society of Chemical Industry.
自噬在真核生物中发挥着重要作用。我们研究了其在松材线虫（Bursaphelenchus xylophilus）中的作用，松材线虫是松材线虫萎蔫病（PWD）的病原体，以寻找针对 PWD 的有前途的控制策略。
我们通过定量逆转录聚合酶链反应（qRT-PCR）分析了 Pinus thunbergii 中调节活性氧（ROS）代谢的 PtRBOH1 和 PtRBOH2 的表达水平，以及 PWN 中三种自噬基因 BxATG5、BxATG9 和 BxATG16 的表达，并测量了松树茎中 H2O2 的含量，ROS 代谢的主要产物。在早期感染过程中，PWN 中自噬基因的表达与松树 ROS 代谢之间存在相关性。我们还发现，根据 qRT-PCR、透射电子显微镜和 Western blot 分析，氧化应激诱导 PWN 中的自噬。通过 3-甲基腺嘌呤抑制自噬或沉默 PWN 中的自噬基因 BxATG9 和 BxATG16，表明自噬对于 PWN 在氧化应激下的取食、繁殖力、卵孵化和生存是必不可少的，证实了自噬在 PWN 抗氧化防御中的重要性。同样，我们证明自噬有助于 PWN 的毒力。此外，当自噬被抑制时，PWN 可能通过增强过氧化物酶和过氧化氢酶抗氧化途径的活性来减轻氧化损伤。
自噬有助于抵抗由松树 ROS 代谢引起的氧化应激，从而促进 PWN 的感染。我们的研究结果阐明了 PWN 的防御机制和 PWD 的发病机制，并为通过阻断自噬来控制 PWD 提供了有希望的线索。© 2020 化学工业协会。
