Please wait a minute...
浙江大学学报（农业与生命科学版）
浙江大学学报(农业与生命科学版)  2015, Vol. 41 Issue (03): 252-260    DOI: 10.3785/j.issn.1008-9209.2014.10.202
生物科学与技术     
肾形肾状线虫个体间rDNA内转录间隔区的变异
邓艳凤,徐红兵,田忠玲,郑经武*
浙江大学农业与生物技术学院生物技术研究所,杭州310058
Interindividual variability of internal transcribed spacer  region of ribosomal DNA in Rotylenchulus reniformis
Deng Yanfeng, Xu Hongbing, Tian Zhongling, Zheng Jingwu*
(Institute of Biotechnology, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China)
 全文: PDF(22920 KB)   HTML ( ) 
摘要： 利用DNA序列分析技术对我国浙江、福建和重庆3个地区的肾形肾状线虫(Rotylenchulus reniformis,RN)种内群体及群体内个体间核糖体RNA 基因(rDNA)内转录间隔区(internal transcribed spacer,ITS)序列进行PCR扩增及序列变异分析。结果显示不同的群体间均获得2种PCR产物,标记为变异类型Ⅰ(RN_VAR1)和变异类型Ⅱ(RN_VAR2)。基于每个群体内2条雌虫分别挑取各变异类型的5个克隆测序,共得到60个克隆序列。经序列比对分析,发现肾形肾状线虫rDNA基因2种类型的ITS区变异很大,其中变异类型Ⅰ序列长度为705~712 bp,鸟嘌呤和胞嘧啶(guanine and cytosine content,GC)含量为45.1%~46.7%;变异类型Ⅱ序列长度为854~860 bp,GC含量为48.4%~50.0%。2种类型的ITS相似度(包括5.8S RNA基因)仅为62.1%~65.6%,而各rDNA变异类型内部各个克隆序列也存在差异,变异类型Ⅰ内个体间相似度为89.9%~100%;变异类型Ⅱ内个体间相似度为91.4%~99.8%。系统进化分析表明2种变异序列明显分成2支,同时通过ITS序列分析无法将3个地方群体区分开来。经实时荧光定量PCR(quantitative real-time PCR,qPCR)检测发现RN_VAR1含量稍大于RN_VAR2,分别占保守18S基因的rDNA重复单位含量的56%和40%。同时,还发现肾形肾状线虫的2种rDNA-ITS变异类型与已报道的2种18S RNA基因变异类型相对应,表明肾形肾状线虫存在2种rDNA变异类型。
Abstract: Ribosomal RNA gene (rDNA) is conservative and it is composed of numerous copies of tandemly repeated transcription units within the genome that has been recognized as an attractive marker for phylogenetic studies. It consists of the 18S, 5.8S, and 28S genes as well as internal transcribed spacer (ITS) region and external transcribed spacer (ETS) region. As members of a sequence family, the multiple copies of the rDNA do not evolve independently. They tend to evolve in a concerted fashion, which means that in a species the repeats evolve together. Previous study shows  that there are two major variants in the 18S rRNA gene of the single  Rotylenchulus reniformis. The variation within ITS region of rRNA gene among R. reniformis populations from Zhejiang, Fujian and Chongqing of China was reported. Two bands of 18S-ITS sequence with lengths of 1 250 bp and 1 400 bp (include ≈480 bp 18S rDNA sequence, the whole ITS sequence and ≈50 bp 28S rDNA sequence) were amplified from each nematode of three populations of R. reniformis, which named as variant 1 (RN_VAR1) and variant 2 (RN_VAR2), respectively. The amount of variation was assessed by sequencing five  clones from each variant from six female reniform nematodes of three populations, with a total of 60 sequences. These sequences were distinguished, based on multiple sequence alignment (MSN), the percent identity and guanine and cytosine content (GC) content of the ITS and clustering in phylogenetic trees. The length and GC content of ITS region were characterized by RN_VAR1 (705712 bp, 45.1%46.7%)  and RN_VAR2  (854860 bp, 48.4%50.0%), respectively. The percent identity between RN_VAR1 and RN_VAR2 was relatively low which only ranged between 62.1% and 65.6%. The percent identity between all clones in RN_VAR1 was 89.9%100%, and that in RN_VAR2 was 91.4%99.8%. Phylogenetic tree analyses based on neighbor-joining method showed  that both RN variants could  be distinguished from other nematodes by ITS sequence alignment, while it was hard for differentiation of R. reniformis  intrapopulation. The quantitative real-time polymerase chain reaction (qPCR) experiments showed that RN_VAR1 made up 56% of rDNA units with relatively well-conserves in 18S RNA gene, whereas RN_VAR2 was 40%. The two ITS variants, RN_VAR1 and RN_VAR2, were  consistent to the  reported two 18S RNA gene variants, respectively. The results confirm  that there are two rDNA variant types in reniform nematode. This variation may be as a result of ancestral interspecific hybridization or gene recombination between sister chromatids, leading to the coevolution of the rDNA sequences on these chromosomes.
出版日期: 2015-05-20
CLC:  Q 933  
服务　　
把本文推荐给朋友
加入引用管理器
E-mail Alert
RSS
作者相关文章　　
邓艳凤
徐红兵
郑经武
田忠玲

引用本文:

邓艳凤,徐红兵,田忠玲,郑经武. 肾形肾状线虫个体间rDNA内转录间隔区的变异[J]. 浙江大学学报(农业与生命科学版), 2015, 41(03): 252-260.

Deng Yanfeng, Xu Hongbing, Tian Zhongling, Zheng Jingwu. Interindividual variability of internal transcribed spacer  region of ribosomal DNA in Rotylenchulus reniformis. Journal of Zhejiang University (Agriculture and Life Sciences), 2015, 41(03): 252-260.

链接本文:

http://www.zjujournals.com/agr/CN/10.3785/j.issn.1008-9209.2014.10.202    或    http://www.zjujournals.com/agr/CN/Y2015/V41/I03/252

No related articles found!