基于荧光原位杂交的藜属植物核型分析

为精确地识别藜属植物染色体组的核型特征,该文研究了4种来自青海高原的野生藜属植物(灰绿藜、藜、菊叶香藜及杂配藜)和1种从美国引进的栽培藜麦品种PI614932-HX(3)基于染色体荧光原位杂交(rDNA FISH)的核型。利用5S rDNA和45S rDNA对5种藜属植物有丝分裂中期的染色体进行FISH研究。藜属植物的核型分析结果表明:(1)藜属植物中存在二倍体(2n=2x=18)和四倍体(2n=4x=36)两种倍性,藜麦和灰绿藜为四倍体,其余3种为二倍体。(2)藜麦、灰绿藜、藜、菊叶香藜及杂配藜的核型公式分别为2n=4x=36=34m(2AST)+2sm,2n=4x=36=32m(4AST)+4sm,2n=2x=18=16m(4AST)+2sm,2n=2x=18=18m及2n=2x=18=16m+2sm。(3)染色体由大部分的中部着丝粒染色体(m)和少部分近中部着丝粒染色体(sm)组成。(4)核型类型除了菊叶香藜为1B以外,其余均属于2B类型。(5)在藜麦、灰绿藜及藜中具有分布位置不同、数量不等的双随体。5S rDNA、45S rDNA FISH结果表明:(1)藜麦和灰绿藜的染色体上存在2对5S rDNA位点和1对45S rDNA位点,藜、杂配藜的染色体上存在1对5S rDNA位点和1对45S rDNA位点,菊叶香藜的染色体上只存在1对5S rDNA位点。(2)5S rDNA和45S rDNA位点均位于染色体的短臂上。该研究首次获得了藜属植物基于5S rDNA和45S rDNA荧光原位杂交核型,为藜属植物亲缘关系研究和细胞生物学研究提供了分子细胞遗传学依据。

Karyotype analysis of Chenopodium species based on fluorescence in situ hybridization

In order to get much more precise information on the karyological characteristics of Chenopodium L. species, the karyotypes of four wild Chenopodium species from Qinghai Plateau, including C. glaucum, C. ablum, C. foetidum and C. hybridum, and one cultivated C. quinoa PI614932-HX(3)introduced from the United States were analyzed by using chromosome fluorescence in situ hybridization(rDNA FISH). 5S rDNA and 45S rDNA were mapped on the metaphase chromosomes of the five species by FISH. The results of the karyotype analysis were as follows:(1)There were two kinds of ploidies in these Chenopodium species, including a diploid(2n=2x=18)and a tetraploid(2n=4x=36), C. quinoa and C. glaucum were tetraploids, and the other three species were diploids.(2)The karyotype formulas of C. quinoa, C. glaucum, C. ablum, C. foetidum and C. hybridum were 2n=4x=36=34m(2AST)+2sm, 2n=4x=36=32m(4AST)+4sm, 2n=2x=18=16m(4AST)+2sm, 2n=2x=18=18m and 2n=2x=18=16m+2sm, respectively.(3)The chromosomes of Chenopodium were mainly composed of metacentric chromosomes(m)and a few submetacentric chromosomes(sm).(4)Except for C. foetidum belonging to 1B type, the others belonged to 2B type.(5)There were double satellites distributed at different positions with different numbers on the chromosomes of C. quinoa, C. glaucum and C. ablum. The results of 5S rDNA and 45S rDNA FISH were as follows:(1)There were two pairs of 5S rDNA loci and one pair of 45S rDNA loci on the chromosomes of C. quinoa and C. glaucum, one pair of 5S rDNA and one pair of 45S rDNA on the chromosomes of C. ablum and C. hybridum, and only one pair of 5S rDNA on the chromosomes of C. foetidum.(2)5S rDNA and 45S rDNA loci were all located on the short arm of the chromosomes. It is the first report on karyotype analysis with 5S rDNA and 45S rDNA loci in Chenopodium species and the results will provide a cyto-moecular genetic basis for phylogeny and cell biology research of Chenopodium species.