【摘要】 为了探寻蔷薇属植物亲缘关系及系统发育研究的分子细胞遗传学证据,该研究采用双色FISH(荧光原位杂交)技术,对原产中国7个组的17种蔷薇属植物的45S和5S rDNA进行了定位分析。结果表明:(1)多数蔷薇属植物1组染色体对应1个45S rDNA位点和1个或2个5S rDNA位点,偶尔出现1～2个rDNA位点的丢失,但复伞房蔷薇(Rosa brunonii)的1组染色体对应了2个45S rDNA位点。(2)二倍体的蔷薇属植物至少有1对5S rDNA位点与45S rDNA位点共定位,而四倍体材料的5S rDNA位点与45S rDNA位点没有共定位,但所有四倍体材料均至少有1种rDNA信号纯合,表明它们应为二倍体直接加倍产生的同源四倍体。(3)绝大多数材料45S rDNA位于染色体短臂、5S rDNA位于染色体长臂,但缫丝花(R.roxburghii f.roxburghii)有1个5S rDNA信号位于染色体的短臂上,表明它与蔷薇属其他种的亲缘关系较远。(4)阿克苏地区和伊犁地区的疏花蔷薇的核型不同,且45S和5S rDNA的数量和位置不同,分子细胞遗传学证据也支持阿克苏地区的疏花蔷薇应为疏花蔷薇的新变种。(5)该研究中共有8个二倍体和6个四倍体蔷薇属植物的双色FISH为首次报道。研究认为,无论二倍体还是四倍体蔷薇属植物中出现的异形同源染色体、rDNA信号位置在同源染色体上的差异以及rDNA信号的增加和丢失,可能都与染色体结构变异和染色体重组有关,在分子细胞遗传学水平上证明染色体结构变异和染色体重组在蔷薇属植物演化过程中具有重要的作用。更多还原

【Abstract】 In order to explore the molecular cytogenetic evidence of the relationship and phylogeny of genus Rosa, we located and analyzed the 45 S and 5 S rDNA of 17 species from 7 sections in China by using the technique of two-color FISH(fluorescence in situ hybridization). The results suggested that:(1) one set of chromosomes corresponded to one 45 S rDNA locus(except R. brunonii, which corresponded to two 45 S rDNA), and one or two 5 S rDNA loci.(2) At least one pair of 5 S rDNA signals were co-located with 45 S rDNA signals in diploid rose species, while 5 S rDNA signals did not collocated with 45 S rDNA signals in all of the tetraploid species; However, all tetraploid materials had at least one kind of rDNA signal homozygosity, indicating that they should be homologous tetraploid generated by direct doubling of diploid.(3) R. roxburghii f. roxburghii(sect. Microphyllae) was more distantly related to other species of Rosa, because it had a 5 S rDNA signal on the short arm of the chromosome, unlike other species of Rosa.(4)The karyotype as well as the numbers and locations of 45 S and 5 S rDNA were different in Aksu region and Yili region. The molecular cytogenetic evidence supported that R. laxa in Aksu region should be a new variety of the R. laxa.(5) To the best of our knowledge, the two-color FISH analyses of tetraploid roses(6 taxa) and 8 diploid taxa has been reported for the first time in this study. The study provided that the heterologous chromosomes, differences of positions of rDNA signals on homologous chromosomes and the increase and loss of rDNA signals in both diploid and tetraploid plants in Rosa may be related to the structure variation and recombination of chromosomes. The structure variation and recombination of chromosomes were proved to played an important role in the evolution of Rosa at the level of molecular cytogenetics更多还原