中国花生新病害茎线虫病病原鉴定及其种群遗传多样性

Peanut stem nematode disease cause by Ditylenchus sp. was firstly found in peanut areas in China by applicant. It can cause great losses of peanut in field. Peanut stem nematode disease, which cause by Ditylenchus africanus.were reported only in South Africa. Previous research by applicants found that there were differences of morphological characters and sequences of rDNA-ITS region between Ditylenchus sp.and D.distructor or Ditylenchus africanus. Peanut is an important oil crop in China, eanut stem nemaode disease would threat peanut industry. The applicant will conduct systematic research on distribution of peanut stem nematode in China, identify Ditylenchus species or race in China using methods of morphological characteristics, host ranges and molecular biology, analysis genetic diversity of Ditylenchus sp. parasitising penut in China, definite the differences of host range, pathogenicity and genetic diversity among Ditylenchus sp. parasitising peanut and D.distructor parasitising sweetpotato in China. Achievements of the project are expected to ascertain distributiion and taxonomic statue of Ditylenchus sp. parasitizing penut in China. The research results would have important theoretical significance and applied value for prevention, control and quarantine for peanut stem nematode disease in China.

申请人首次在我国花生产区发现茎线虫病新病害，并造成严重为害。花生茎线虫病仅在南非有报道，为花生上最重要的线虫病害，病原线虫为非洲茎线虫（Ditylenchus africanus）。申请者前期调查发现我国花生茎线虫的形态与rDAN-ITS区序列与甘薯上腐烂茎线虫（D.distructor）及非洲茎线虫存在差异。基于花生是我国重要的油料作物，花生茎线虫病的发生将对我国花生产业构成极大威胁，本课题通过对中国花生茎线虫的地理分布进行系统调查，对不同种群进行分离、纯化、繁殖，通过形态学、寄主范围测定、分子生物学方法进行花生茎线虫种或生理小种的鉴定，分析花生茎线虫不同种群间的遗传多样性；确定花生茎线虫种群与甘薯上腐烂茎线虫种群在寄生范围、致病性及遗传多样性方面差异。研究成果对于探明花生茎线虫病在我国的地理分布，明确其病原分类地位，指导我国花生茎线虫病的预防、控制和检疫有重要理论意义和应用价值。

花生是我国重要的油料作物，花生茎线虫病的发生将对我国花生产业构成极大威胁。本项目调查了我国福建、山东、河北、山西、浙江、四川等6个省份多个地区的花生样本，从山东、河北两省花生样本上分离到花生茎线虫，通过显微形态学、分子生物学及生物学方法，确定了危害我国部分花生主产区的茎线虫为一新种并命名为花生茎线虫Ditylenchus arachis n. sp.。对山东、河北两省的花生产区花生茎线虫病害进行了进一步的调查，在山东省市中区、临沂市费县和蒙阴县、泰安市的新泰县、莱芜市钢城区、聊城市的冠县；河北省的邢台市巨鹿县和平乡县、邯郸市的曲周县、邱县和馆陶县、迁安县等发现花生茎线虫，进行了定位并对其危害性进行了调查，花生茎线虫已成为当地花生生产、不为人知的威胁。通过分子生物学方法分析了花生茎线虫的遗传多样性，比较了花生茎线虫与近似种的亲缘关系，表明花生茎线虫D. arachis n. sp.优先相聚成簇，并与 D. destructor进一步聚为一个大分支，与D. halictus，D. myceliophagus ，D. africanus亲缘关系较远。通过盆栽接种、伤口接种及组织病理学观察，花生茎线虫不侵染甘薯和马铃薯（甘薯茎线虫却能侵染甘薯）。被接种茎线虫的花生植株较未接种线虫的植株表现出与田间相似的症状。组织病理学观察结果显示：花生茎线虫可寄生花生的根系、胚栓、果荚及种子，其中以果荚外果皮和内果皮的线虫最多。同时，从花生茎线虫的培养条件、田间杂草寄主及花生种荚携带花生茎线虫等方面也进行了较为全面的研究，为该线虫的防控提供理论依据。