陕西天竺山华山松分离线虫的鉴定及对马尾松的致病性

Identification of nematode isolated from Pinus armandii and its pathogenicity on P. massoniana in Tianzhu Mountain in Shaanxi Province

陕西省山阳县天竺山林场海拔1 500 m处发现较多死亡的华山松,从枯死木中分离获得1种伞滑刃属线虫。采用rDNA-ITS-PCR法将测得的ITS序列与NCBI中已提交的线虫序列比对,发现与拟松材线虫的多个ITS序列相似性达到99%,并将与其同源性相近的序列构建系统发育树,结合形态观察结果,鉴定该未知线虫为拟松材线虫Bursaphelenchus mucronatus,虫株定名为Nxym3。接种实验表明,Nxym3能够引起3年生马尾松实生苗发病,发病率为50%,病情指数为0.37,从接种发病的松苗中均可获得该线虫;枯死松苗的发病特征与接种松材线虫的松苗发病特征相似,证实Nxym3对3年生马尾松苗有一定的致病性。

The dead Pinus armandii were found at the altitude of 1 500 m in Tianzhu Mountain in Shanyang County, Shaanxi Province and nematodes were isolated from the dead wood. ITS sequence of the nematode was obtained with rDNA-ITS-PCR method and compared with some ITS sequences of Bursaphelenchus mucronatus submitted in Genbank and shared 99%. Phylogenetic tree was constructed as well with the similar homology sequences. Combined with morphological observations, the nematode was identified as B. mucronatus and named as Nxym3. The results of inoculation experiments showed Nxym3 could cause wilt on the 3-year-old seedlings of P. massoniana. The incidence rate was 50% and the disease index was 0. 37. The diseased seedlings inoculated with B. mucronatus showed the same symptoms as those inoculated with B. xylophilus. And the nematodes were re-isolated from the diseased seedlings. It confirmed that Nxym3 had certain pathogenicity to the 3-year-old seedlings of P. massoniana.