泡桐高密度分子遗传图谱的构建

High-density molecular genetic map construction in Paulownia fortunei

以毛泡桐Paulownia tomentosa为母本、白花泡桐Paulownia fortunei为父本进行正反交,以杂交获得的子一代(F1)构建泡桐连锁图谱的作图群体,选取限制性内切酶EcoRI对185个样品的基因组进行酶切,利用Illumina Hiseq2000测序平台进行RAD测序建库,以白花泡桐基因组为参考,采用SOAP2软件进行序列比对,利用筛选到的单核苷酸多态性SNP(Single Nucleotide Polymorphisms,SNP)位点对该群体进行基因型分析,使用Joinmap version 4.0软件构建泡桐连锁遗传图谱。结果表明:利用RAD测序技术共获得551894个SNP标记,构建了含20个连锁群的泡桐遗传连锁图谱,该图谱的总图距为2050.77cM,标记间平均图距为0.58cM,图谱预期长度为2064.29cM,图谱基因覆盖度为99.35%。本研究构建的泡桐连锁遗传图谱具有高精度和覆盖泡桐基因组完整(构建连锁群数目等于泡桐单倍体基因组染色体的数目)的优点,为泡桐分子育种学研究奠定了基础。

In the present study, RAD-seq(Restriction-site associated DNA sequencing) technology was utilized to construct the linkage map of Paulownia. Reciprocal crosses between Paulownia tomentosa(mother parent) and Paulownia fortunei(male parent) were performed to produce the F1 hybrids, and then the F1 hybrids were used to construct linkage map. The genomes of 185 samples were digested by EcoRI restriction enzyme, and Illumina Hiseq 2000 platform was utilized for RAD-seq. The obtained RAD-seq reads were then aligned to the reference Paulownia fortunei genome by SOAP2 software. The population genotype analysis was performed according to the screened Single Nucleotide Polymorphisms(SNPs). Finally, Paulownia linkage genetic map was constructed using Joinmap version 4.0 software. Basing on RAD-seq, 551,894 SNP markers were obtained, and the linkage map of Paulownia that containing 20 genetic linkage groups was constructed. The expected length of the map was 2064.29cM, while the total plot distance of the Paulownia linkage map was 2050.77cM. The average distance between the markers was 0.58cM, and the gene coverage of this map was 99.35%.In this study, the constructed genetic linkage map of Paulownia has the advantages of high accuracy and complete genome coverage(i.e., the number of linkage groups was equal to the number of chromosomes of Paulownia haploid). And the achieved results in the present study can provide basic theoretical foundation for the molecular breeding of Paulownia.