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本文基于Gen Bank中登录的14种松材线虫组线虫的28S、18S和ITS部分基因DNA序列,利用遗传距离法及分子生物学方法评价其各自作为松材线虫组DNA条形码序列的适用性。结果显示,28S(拟松材线虫不分亚种)、28S(拟松材线虫分亚种)、18S和ITS的基因序列种内成对遗传距离平均值分别为0.0071、0.0030、0.0007、0.0043,种间成对遗传距离平均值分别为0.0476、0.0454、0.0052、0.1556,其中28S、18S基因序列种内及种间距离存在一定程度的重叠,ITS具有一定程度的Barcoding gap。3个基因序列构建的NJ进化树显示,28S、ITS构建的系统进化树具有较高的节点支持率,可以有效将14个松材线虫组线虫分离成独立分支,而且28S可以有效鉴别出拟松材线虫的2个亚种;基于18S基因构建的进化树不能对吉拉尼伞滑刃线虫、日本冷杉伞滑刃线虫、拟松材线虫进行有效区分。因此,28S、ITS区具有一定的遗传距离间隔以及相对较高的物种识别率,可以作为松材线虫组线虫候选条形码基因。
Based on the DNA sequences of 28S, 18S and ITS genes of 14 species of Nematodes released by GenBank, genetic distance and molecular biological methods were used to evaluate their applicability as DNA barcode sequences of pine wood nematode. The results showed that the mean in-pair genetic distance between 28S (subgenus Bursaphelenchus xylostella), 28S (subfasciatus subfasciatus), 18S and ITS were 0.0071,0.0030,0.0007,0.0043, The average genetic distance between pairs was 0.0476,0.0454,0.0052,0.1556 respectively, of which the 28S and 18S gene sequences had some overlap within and between species distances. ITS had a certain degree of Barcoding gap. The NJ phylogenetic tree constructed by 3 gene sequences showed that phylogenetic tree constructed by 28S and ITS had higher nodal support rate, which could effectively separate 14 Bursaphelenchus xylophilus nematodes into independent branches, and 28S could effectively identify pseudo-pine The two subspecies nematode; phylogenetic tree based on the 18S gene can not be Jilani umbrella glomerulus, Japan Firosteal Bursaphelenchus, the effective division of the pine wood nematode. Therefore, 28S and ITS regions had some genetic distance and relatively high species recognition rate, which could be used as candidate nematode candidate barcode genes in pine wood nematode group.