甘肃省黄芩根结线虫病病原种类鉴定

通过形态学与分子生物学相结合的方法对引起甘肃省陇西县黄芩根结线虫病的病原种类进行了鉴定,并采用室内人工接种的方法测定其对黄芩的致病性。结果表明,从黄芩根系分离的根结线虫其形态特征及测量值与北方根结线虫Meloidogyne hapla基本一致。该线虫种群rDNA-ITS和28S rDNA D2/D3序列与NCBI数据库中的北方根结线虫序列相似性分别为99.60%和99.74% (rDNA-ITS: JX024147; 28S rDNA D2/D3: MW288147)。贝叶斯系统发育树显示,该线虫群体与其他北方根结线虫群体聚为一支,置信度在95%以上。利用北方根结线虫特异性引物Mh-F/Mh-R扩增并测序得到457 bp的特异性片段。因此,基于形态学结合rDNA-ITS、28S rDNA D2/D3序列和特异性片段长度,将黄芩根结线虫病病原鉴定为北方根结线虫M.hapla。接种该线虫后的黄芩生长缓慢,叶片黄化,40 d后须根上有明显的根结。经分离鉴定,致病群体为北方根结线虫。综上所述,甘肃省陇西县黄芩根结线虫病病原为北方根结线虫M.hapla,该线虫对黄芩具有较强的致病性,其繁殖系数为1.997。

Identification of pathogens of root-knot nematode disease of Scutellaria baicalensis in Gansu province

In this study, the species causing root knot nematode disease on Scutellaria baicalensis in Longxi county, Gansu province was isolated and identified and its pathogenicity to S. baicalensis was determined by indoor artificial inoculation. The results showed that the morphological characteristics and measurements of the nematode population from S. baicalensis were basically consistent with those of Meloidogyne hapla. rDNA-ITS and 28S rDNA D2/D3 sequences showed 99.60% and 99.74% identity with M.hapla in NCBI, respectively (rDNA-ITS: JX024147; 28S rDNA D2/D3: MW288147). The Bayesian phylogenetic tree indicated that this nematode population clustered with other M.hapla populations with a confidence level of 95%. A specific fragment of 457 bp in size was obtained by amplification with the M. hapla-specific primers Mh-F/Mh-R and sequencing. Based on morphology, rDNA-ITS, 28S rDNA D2/D3 sequences, and the specific sequence, the pathogen of the nematode population on S. baicalensis was identified as M.hapla. After inoculation with this nematode population, S. baicalensis grew slowly with yellowing leaves, and obvious root knots were observed on fibrous roots 40 days after inoculation. In conclusion, the pathogen responsible for the root knot nematode disease of S. baicalensis in Longxi county, Gansu province is M.hapla, which demonstrates strong pathogenicity to S. baicalensis with a reproductive coefficient of 1.997.