腐烂茎线虫种内不同群体形态及遗传分析

Morphological and genetic analysis on different populations of Ditylenchus destructor

对来自国内的13个腐烂茎线虫群体和1个荷兰的鳞球茎茎线虫群体进行了ITS1区的扩增和5种限制性内切酶RsaⅠ、HaeⅢ、MspⅠ、HinfⅠ、AluⅠ的限制性片段长度多态性分析(RFLP),发现13个腐烂茎线虫群体存在2种不同的酶切图谱,2种图谱在RsaⅠ、HaeⅢ、HinfⅠ和AluⅠ4种酶的酶切位点上存在差异,而鳞球茎茎线虫群体的RFLP图谱与腐烂茎线虫的RFLP图谱相比则在全部的5种限制性内切酶的酶切位点上存在差异。根据RFLP酶切图谱的差异,可以将腐烂茎线虫的13个群体分为A、B2种基因型。A基因型包括DeSD1、DeSD2、DeSD3和DeJS14个群体,B基因型包括DeAH1、DeAH2、DeHB1、DeHB2、DeJS2、DeSX、DeSD4、DeTJ1和DeTJ29个群体。对ITS1区的序列进行比对,发现A基因型4个群体的差异在1%～4%之间,B基因型9个群体的差异在0～1%之间,鳞球茎茎线虫与腐烂茎线虫种间的差异在39%～48%之间。对4个腐烂茎线虫群体和1个鳞球茎茎线虫群体进行了形态学上的测量,发现腐烂茎线虫群体的2个基因型间除在4个形态测计值c值、尾长、V值和V’值存在显著差别外,在其它形态测计值上并无显著差异。ITS1区的RFLP图谱和序列比对以及形态测计数据都表明中国的腐烂茎线虫群体存在2种基因型。

ITS1 （internal transcribed spacer 1） regions were amplified from 13 Chinese populations of Ditylenchus destructor and one Dutch population of Ditylenchus dipsaci. ITS1 regions of these populations were digested by five enzymes Rsa Ⅰ, Hae Ⅲ, Msp Ⅰ, Hinf Ⅰ and Alu Ⅰ. ITS1-RFLP patterns revealed that two patterns existed in 13 Chinese populations of D. destructor with different fragments obtained by four enzymes Rsa Ⅰ, Hae Ⅲ, Hinf Ⅰ and Alu Ⅰ, and ITS1-RFLP patterns of D. dipsaci and D. destructor were different in fragments obtained by all five enzymes. 13 Chinese populations of D. destructor were divided into two genotypes, i.e. genotype A and B. Genotype A included populations of DeSD1, DeSD2, DeSD3 and DeJS1, and genotype B included populations of DeAH1, DeAH2, DeHB1, DeHB2, DeJS2, DeSX, DeSD4, DeTJ1 and DeTJ2. ITS1 regions were also sequenced and the alignments showed that the pairwise sequence divergences of four populations in genotype A were between 1% and 4%, and that of nine populations of genotype B were 0 and 1%, and the sequence divergences of D. dipsaci and D. destructor were 39% and 48%. Morphometric characters were analysed on four populations of D. destructor and one population of D. dipsai. The results demonstrated that no significant difference in most morphometric characters except c, tail, V and V’ among populations of two genotypes A and B of D. destructor. The ITS1-RFLP patterns, ITS1 sequence analysis and morphometric data supported that two genotypes of D. destructor were existed in China.