本研究对分离自山西省马铃薯、甘薯和薯蓣块茎中的腐烂茎线虫8个群体进行形态特征观察和数值测量,对形态数据进行SPSS差异显著性和PCA分析;采用通用引物对其ITS rDNA进行PCR扩增与序列测定,利用Geneious Prime 2019.2.3和DNAMAN 9.0软件计算相似距离和序列比对,Arlequin 3.5软件中的AMOVA模块分析分子变异方差,MrBayes 3.2.7构建贝叶斯系统发育树,并用PopART 4.8.4软件构建TCS单倍型网络图.结果表明,腐烂茎线虫群体YH277、YH279、tg38、XF01、CZ15、TY15、tg49属于A型,寄主有甘薯、马铃薯和薯蓣;为害马铃薯群体PX04属于C型.PX04和其余7个群体在形态上存在明显差异,尾部稍尖;PCA分析显示PX04与其他7个群体可以明显区分开.选用薯类作物为寄主的腐烂茎线虫77条ITS序列构建TCS单倍型网络图,结果显示共享单倍型2个和独享单倍型26个.其中H1单倍型是共享率最高的,推测其可能为祖先单倍型;26个独享单倍型中马铃薯群体独享数目最多,其群体单倍型和核苷酸多样性最丰富,单倍型多样性指数Hd值为0.841,群体间核苷酸多样性指数Pi值为0.005 02.AMOVA分析表明,山西省腐烂茎线虫遗传差异主要来源于种群间,腐烂茎线虫A型与C型之间存在较大的遗传分化.
Morphological and genetic analysis on populations of Ditylenchus destructor from Shanxi Province
Eight populations of Ditylenchus destructor were isolated from three tuber crops(Solanum tuberos-um,Dioscorea esculenta and Dioscorea polystachya)in Shanxi Province.Morphology characteristics of D.de-structor populations were observed and measured,and then the morphological data were analyzed by SPSS and PCA software.Nematode universal primers were used for PCR amplification and sequencing of rDNA-ITS.Simi-larity distance and sequence alignment were analyzed by Geneious Prime 2019.2.3 and DNAMAN 9.0 software,respectively.Analysis of variance of molecular variance(AMOVA)was constructed by Arlequin 3.5 software.The phylogenetic tree and haplotype network diagram were constructed by MrBayes 3.2.7 and PopART 4.8.4 software,respectively.The results showed that seven populations of D.destructor(YH277,YH279,tg38,XF01,CZ15,TY15 and tg49)are belong to type A,and their hosts are D.esculenta,S.tuberosum,and D.polystachya.Nevertheless,the PX04 population is belongs to type C and the host is S.tuberosum.The morphology of PX04 population is significantly different from the other seven populations,with the PX04 popu-lation having a slightly pointed tail.PCA analysis result also suggested that PX04 population was obviously sepa-rated from the other seven populations.The result of haplotype network structure was constructed using 77 ITS sequences of D.destructor isolated from D.esculenta,D.polystachya and S.tuberosum.The results showed that two shared haplotypes and 26 unique haplotypes.Among them,the frequency of the H1 was the highest among the three tuber crops,which suggests that it might be an ancestral haplotype;Among 26 unique haplotypes,the highest number of exclusive haplotypes and the most abundant haplotype and nucleotide diversities were found in the population of D.destructor parasitized the S.tuberosum,with a haplotype diversity index(Hd)of 0.841 and the inter-population nucleotide diversity index(Pi)of 0.005 02.The result of AMOVA analysis showed that the genetic differences of the D.destructor in Shanxi Province were mainly from inter-populations,and there was a sizeable genetic differentiation between type A and C of D.destructor.
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