Department of Forest Protection, Nanjing Forestry University, Nanjing, People's Republic of China.
PLoS One. 2013 Aug 19;8(8):e71676. doi: 10.1371/journal.pone.0071676. eCollection 2013.
A nematophagous fungus, Esteya vermicola, is recorded as the first endoparasitic fungus of pine wood nematode (PWN), Bursaphelenchus xylophilus, in last century. E. vermicola exhibited high infectivity toward PWN in the laboratory conditions and conidia spraying of this fungus on Japanese red pine, Pinus densiflora, seedlings in the field protected the pine trees from pine wilt disease to some extent, indicating that it is a potential bio-control agent against PWN. Previous research had demonstrated that the living fungal mycelia of E. vermicola continuously produced certain volatile organic compounds (VOCs), which were responsible for the PWN attraction. However, identity of these VOCs remains unknown.
METHODOLOGY/PRINCIPAL FINDINGS: In this study, we report the identification of α-pinene, β-pinene, and camphor produced by living mycelia of E. vermicola, the same volatile compounds emitted from PWN host pine tree, as the major VOCs for PWN attraction using gas chromatography-mass spectrometry (GC-MS). In addition, we also confirmed the host deception behavior of E. vermicola to PWN by using synthetic VOCs in a straightforward laboratory bioassay.
CONCLUSIONS/SIGNIFICANCE: This research result has demonstrated that the endoparasitic nematophagous fungus, E. vermicola, mimics the scent of PWN host pine tree to entice PWN for the nutrient. The identification of the attractive VOCs emitted from the fungus E. vermicola is of significance in better understanding parasitic mechanism of the fungus and the co-evolution in the two organisms and will aid management of the pine wilt disease.
上世纪，一种食线虫真菌——蜡蚧轮枝菌被记录为松材线虫（Bursaphelenchus xylophilus）的首例内寄生真菌。在实验室条件下，蜡蚧轮枝菌对松材线虫表现出很高的感染力，并且将该真菌的分生孢子喷洒在日本赤松（Pinus densiflora）实生苗上，在一定程度上保护了松树免受松材线虫病的侵害，这表明它是一种潜在的防治松材线虫的生物防治剂。先前的研究表明，蜡蚧轮枝菌活体真菌菌丝不断产生某些挥发性有机化合物（VOCs），这些化合物是吸引松材线虫的原因。然而，这些 VOCs 的身份仍然未知。
方法/主要发现：在这项研究中，我们报告了使用气相色谱-质谱联用仪（GC-MS）鉴定出蜡蚧轮枝菌活体菌丝产生的α-蒎烯、β-蒎烯和莰烯，以及从松材线虫宿主松树中释放的相同挥发性化合物，这些都是吸引松材线虫的主要 VOCs。此外，我们还通过直接的实验室生物测定，使用合成 VOCs 证实了蜡蚧轮枝菌对松材线虫的宿主欺骗行为。
结论/意义：这项研究结果表明，内寄生线虫食真菌——蜡蚧轮枝菌模仿松材线虫宿主松树的气味来引诱松材线虫获取营养。鉴定出从真菌蜡蚧轮枝菌中释放出的有吸引力的 VOCs，对于更好地理解真菌的寄生机制以及这两个生物体的共同进化具有重要意义，并将有助于松材线虫病的管理。
