松树挥发物促进松材线虫扩散型四龄向繁殖型成虫转型的作用机理

松材线虫病是我国最具毁灭性的森林灾害之一，该病的病原为松材线虫，其生活史分为扩散型周期和繁殖型周期。松材线虫扩散型四龄侵入健康松树后，被刺激迅速转型为能够致死松树的繁殖型成虫。然而，松材线虫扩散型四龄如何被刺激转型为繁殖型成虫的作用机理尚不清楚。申请人前期研究发现，松树的单萜类挥发物能够显著促进这一转型过程。因此，本项目以松材线虫扩散型四龄为研究对象，1）通过比较松树挥发物刺激前后线虫的形态和生理差异，明确松树挥发物促进松材线虫扩散型四龄向繁殖型成虫转型的发育特征和相应时间节点；2）通过比较各时间节点松材线虫基因表达情况（重点关注发育、代谢和受体等基因），筛选差异表达基因并验证基因功能，确认松树挥发物促进松材线虫扩散型四龄向繁殖型成虫转型的关键基因。最终，阐明松树挥发物促进松材线虫扩散型四龄向繁殖型成虫转型的作用机理，为松材线虫病的科学防治提供新的思路和理论基础。

Pine wilt disease (PWD) poses a serious threat to pine forests in China since 1980s. The spread of Bursaphelenchus xylophilus depends on the transformation of dispersal-stage larvae 4 (DL4, dauer) from DL4 to adult for reproduction to kill pines. However, the mechanism of this transformation is not clear. Our previous study found that pine volatiles could promote the transformation of DL4 to adult (dauer recovery) of B. xylophilus. Thus, we plan to analyze the process of DL4 transformation of B. xylophilus promoted by pine volatiles based on morphology and physiology and select transformation time points. Then, the transcriptomes of transforming DL4 at different time points will be sequenced and real-time PCR will be performed to find out differential expression genes (DEGs). The function of these DEGs on transformation will be identified using RNA interference. Finally, the mechanism of DL4 transformation of B. xylophilus promoted by pine volatiles will be illuminated. This study will provide new idea and theory for PWD control.