St基因组中的CRW同源序列在偃麦草中的FISH分析  

FISH analysis of a CRW-homology sequence from Pseudoroegneria spicata in Thinopyrum ponticum and Th. intermedium

作　　者：陆坤[1,2] 徐柱[2] 刘朝[1] 张学勇[1] 

机构地区：[1]中国农业科学院作物科学研究所农业部作物种质资源与生物技术重点开放实验室,北京100081 [2]中国农业科学院草原研究所农业部草地资源与生态重点开放实验室,呼和浩特010010

出　　处：《遗传》2009年第11期1141-1148,共8页Hereditas（Beijing)

基　　金：国家自然科学基金项目(编号:30671293)资助

摘　　要：为了确定十倍体长穗偃麦草(Thinopyrum ponticum,Liu&Wang)和六倍体中间偃麦草(Th.intermedium,[Host]Barkworth&Dewey)的基因组组成,根据野生一粒小麦(Triticum boeoticum)着丝粒自主型反转录转座子(CRW)序列设计特异引物,以二倍体拟鹅观草(Pseudoroegneria spicata,áLve)基因组DNA为模板进行PCR扩增,筛选到一条St基因组着丝粒区相对特异反转录转座子的部分序列pStC1,长度为1.755kb(GenBank登录号:FJ952565),其中有800bp与小麦着丝粒反转录转座子(CRW)的LTR区高度同源,另有小部分片段与其外壳蛋白编码基因(gag)部分同源,并且包含一段富含AGCAAC碱基的重复序列。以pStC1为探针,对十倍体长穗偃麦草的FISH检测结果显示其基因组组成为两个St组3个E组(St1St2EeEbEx);pStC1与中间偃麦草杂交时,不仅St基因组上有强烈的荧光信号,而且E基因组一些染色体的近着丝粒区域也有杂交信号,说明偃麦草属异源多倍体物种在其形成及进化过程中St与E基因组之间在着丝粒及近着丝粒相关区域可能存在协同进化。To verify the genome components of Thinopyrum ponticum Liu＆amp;Wang and Th.intermedium[Host]Barkworth＆amp; Dewey,six specific primer pairs were designed according to the sequence of an autonomous centromeric retrotransposon of wheat（CRW）from Triticum boeoticum.Several DNA fragments were amplified by PCR from the genomic DNA of the diploid species Pseudoroegneria spicataáLve.After sequence alignment,a 1.755 kb fragment was obtained and named as pStC1（St genome centromere associated sequence,GenBank accession No. FJ952565）. This fragment contained an 800 bp fragment highly homologous to the LTR region of autonomous CRW, a short fragment partial homology to the gag region of CRW, and an AGCAAC-rich tandem repeat. Fluorescent in situ hybridization （FISH） using pStC1 as a probe was carried out on the chromosomes of Th. ponticum, Th. intermedium and Triticum aestivum cv. Chinese Spring. Th. ponticum was proved to have two St and three E genomes （St1St2E^eE^bE^k）. In Th. intermedium, strong FISH signals were observed on St genome chromosomes, while faint signals were also found on some E-genome chromosomes at their pericentromeric regions. These results indicated that during speciation of sub-genomes in the allopolyploids of Thinopyrum genus, concerted evolution might have occurred at centromeric and pericentromeric regions.

关 键 词：偃麦草属 着丝粒 近着丝粒 反转录转座子 荧光原位杂交 

分 类 号：S512.1[农业科学—作物学]