云南省紫茎泽兰根结线虫病病原种类鉴定

为明确云南省紫茎泽兰根结线虫病的病原种类,于2019年2月在云南省澜沧县林下三七种植区采集根部带有明显根结的紫茎泽兰根系进行根结线虫分离,通过观察所分离根结线虫的2龄幼虫、雌成虫、会阴花纹特征对其进行形态学鉴定,并利用序列比对、系统发育树分析、序列特异性扩增区段(sequence characterized amplified region,SCAR)对其进行分子生物学鉴定。结果表明,该病原线虫雌成虫会阴花纹呈圆形至卵圆形,背弓中等高或低平,侧区一侧或两侧延伸形成翼状,尾区有刻点,2龄幼虫、雌成虫形态特征及形态测量指标与北方根结线虫Meloidogyne hapla相似;该病原线虫rDNA的ITS序列和mtDNA的COI序列与NCBI数据库中已登录的北方根结线虫相应序列相似度较高,分别达99.35%和98.05%以上;该病原线虫rDNA的ITS序列、mtDNA的COI序列分别以99%、100%的支持率与北方根结线虫聚为同一分支;利用SCAR特异性引物,该病原线虫均能扩增出大小约1 500 bp的基因特异性条带。综合形态学和分子生物学鉴定结果将云南省紫茎泽兰根结线虫病病原种类鉴定为北方根结线虫。

Pathogen identification of Eupatorium adenophorum root-knot nematode disease in Yunnan Province

In order to clarify the pathogen species of Eupatorium adenophorum root-knot nematode dis-ease in Yunnan Province, the root samples with obvious root-knot of E. adenophorum were collected for isolating root-knot nematodes from the undergrowth Panax notoginseng in Lancang County, Yunnan Province in February 2019. The pathogenic nematodes were identified by observing morphological char-acteristics of females, second-stage juveniles and perineal pattern, sequence alignments, phylogenetic analysis and specific amplification of sequence characterized amplified region (SCAR). The results showed that the perineal pattern of this nematode was round or oval, the dorsal arch was moderately high or low, one side or both of the lateral field extended to form a wing shape, the tail region had punc-tations, and the morphological characteristics and morphometric values of second-stage juveniles and fe-males were similar to those of Meloidogyne hapla. The rDNA ITS fragment and the mtDNA COI frag-ment of this nematode were highly similar to those of M. hapla in NCBI database, with a similarity of over 99.35% and 98.05%, respectively. The rDNA and mtDNA sequences of this nematode were clus-tered within the same clade with those of M. hapla with a high support rate of 99% and 100%, respec-tively. Using the SCAR specific primers, a specific band with an expected size of approximately 1 500 bp was amplified from this nematode. Morphological and molecular identification methods identified the pathogen species of E. adenophorum root-knot nematode disease in Yunnan Province as M. hapla.