Madani Mehrdad, Tenuta Mario
Department of Soil Science, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada.
J Nematol. 2018 Sep 3;50(2):163-182. doi: 10.21307/jofnem-2018-011.
Ditylenchus weischeri that parasitizes the weed Cirsium arvense (L.) Scop., 1772, (creeping thistle) was described in 2011 from Russia based on their morphology, ITS-RFLP analysis, and Hsp 90 gene sequence of a few individuals and one field collection of the plant. More recently, we found C. arvense parasitized by D. weischeri in the Prairie Provinces of Canada. Plant host preference for D. weischeri was also distinct from D. dipsaci (Kühn) Filipjev, 1936. In the current study, a comprehensive molecular analysis of many D. weischeri specimens from Canada is presented. Individuals from 41 C. arvense or yellow pea grain samples with seeds of C. arvense from the Prairie Provinces were sequenced for the internal transcribed spacer (ITS rDNA), large subunit (LSU) D2D3 28S rDNA, partial segment of small subunit (SSU) 18S rDNA, and the heat shock protein Hsp 90 gene. The analysis also included D. weischeri individuals from C. arvense from Russia and garlic with D. dipsaci from the Provinces of Ontario and Quebec in Canada. Available sequence data of Ditylenchus species retrieved from GenBank were used to phylogenetically position this species within the genus Ditylenchus . In all studied genes, several single-nucleotide polymorphisms between the Canadian D. weischeri and both Russian haplotype and individuals of D. weischeri from C. arvense from Russia were found. The sequences of ITS rDNA, LSU D2D3 28S rDNA, and Hsp 90 were used to construct separate dendrograms. For each of the three genes examined, D. weischeri was grouped separately from the other Ditylenchus . Ditylenchus samples from C. arvense was positioned to a single clade such as D. weischeri and distinct from D. dipsaci . With past reports of plant host preference and morphology, the results of this study provide further evidence for the fact that D. weischeri is distinct to be separated from D. dipsaci . Furthermore, minor differences in molecular divergence and morphology to the Russian haplotype and limited symptoms of disease on C. arvense in Prairie Canada suggest the Canadian and Russian populations of D. weischeri may be diverging.
2011年，基于形态学、ITS-RFLP分析以及少数个体和一份田间采集植物的Hsp 90基因序列，对寄生在杂草田蓟（Cirsium arvense (L.) Scop.，1772）上的维氏茎线虫（Ditylenchus weischeri）进行了描述，该描述来自俄罗斯。最近，我们在加拿大草原省份发现了被维氏茎线虫寄生的田蓟。维氏茎线虫对植物宿主的偏好也与1936年的燕麦真滑刃线虫（Ditylenchus dipsaci (Kühn) Filipjev）不同。在本研究中，我们对来自加拿大的许多维氏茎线虫标本进行了全面的分子分析。对来自草原省份的41份田蓟或带有田蓟种子的黄豌豆样本中的个体进行了内部转录间隔区（ITS rDNA）、大亚基（LSU）D2D3 28S rDNA、小亚基（SSU）18S rDNA部分片段以及热休克蛋白Hsp 90基因的测序。分析还包括来自俄罗斯田蓟的维氏茎线虫个体以及来自加拿大安大略省和魁北克省带有燕麦真滑刃线虫的大蒜。从GenBank检索到的茎线虫属物种的可用序列数据用于在茎线虫属内对该物种进行系统发育定位。在所有研究的基因中，发现加拿大维氏茎线虫与俄罗斯单倍型以及来自俄罗斯田蓟的维氏茎线虫个体之间存在几个单核苷酸多态性。ITS rDNA、LSU D2D3 28S rDNA和Hsp 90的序列用于构建单独的树状图。对于所检测的三个基因中的每一个，维氏茎线虫都与其他茎线虫属物种分开聚类。来自田蓟的茎线虫样本被定位到一个单一的分支，如维氏茎线虫，并且与燕麦真滑刃线虫不同。结合过去关于植物宿主偏好和形态学的报道，本研究结果进一步证明了维氏茎线虫与燕麦真滑刃线虫不同，应予以区分。此外，与俄罗斯单倍型在分子差异和形态上的微小差异以及加拿大草原田蓟上有限的病害症状表明，加拿大和俄罗斯的维氏茎线虫种群可能正在分化。
