香椿染色体核型分析及SSR分子标记开发

Chromosome Karyotype Analysis and Development of SSR Molecular Markers in Toona sinensis

对香椿进行染色体核型分析和SSR分子标记的开发。染色体核型分析发现两个居群的香椿染色体数都是56条,为2A型,香椿的染色体较为原始,变异较小。转录组测序结果共获得66921条Unigene,从中检索得到13 324个SSR位点,分布于11 184条Unigene中,SSR出现频率为19.91%,平均分布距离为3.84 kb。优势重复基序为单核苷酸、二核苷酸和三核苷酸,分别占SSR总数的62.33%、19.66%和15.99%,单核苷酸A/T为优势重复基元,占总SSR的62.23%,二核苷酸以AG/CT为主要重复基元,占总位点的10.31%,三核苷酸以AAG/CTT为主要重复基元,占4.85%。利用Primer 3.0设计了8 218对引物,随机选取了19对引物对17个香椿种质进行PCR扩增,6对引物显示出可重复的多态性。

Chromosome karyotype analysis and SSR molecular marker development of Toona sinensis were conducted.The karyotype analysis result showed that the number of chromosomes in both populations was 2 n=56,and all of karyotypes for the populations was 2 A type,the chromosome of T.sinensis was relatively primitive with little variation.66 921 Unigenes were obtained by transcriptome sequencing analysis from T.sinensis.A total of 13 324 SSRs were identified from 11 184 Unigenes.The frequency of SSRs from these Unigenes was 19.91%,and the mean distribution distance of loci was 3.84 kb.Meanwhile,the major types such as mononucleotide,dinucleotide and trinucleotide accounted for62.33%,19.66%and 15.99%,respectively.Furthermore,A/T was the predominant mononucleotide repeat type(62.23%),AG/CT was the predominant dinucleotide repeat type(10.31%),and AAG/CTT was the predominant trinucleotide repeat type(4.85%).8 218 pairs of SSR primers were found by Primer 3.0.Randomly 19 pairs of primers were selected for PCR amplification by 17 T.sinensis samples,and 6 PCR products showed clear and reproducible results indicating the polymorphism among these samples.