杜鹃花属映山红与皋月杜鹃的基因组调查

Genome Survey of Rhododendron simsii and Rhododendron indicum

杜鹃花花大色艳、花叶繁茂,灿若云锦,有着“木本花卉之王”的美誉。杜鹃花野生资源在全球有着广泛的地理分布,其中中国分布有566种,是杜鹃花资源的多样化中心。通过对两个杜鹃花种质资源的高通量测序研究,我们首次测定了映山红和皋月杜鹃的基因组,运用生物信息学的方法,分析了两种材料的杂合度、GC含量、重复度等基因组信息,为开展相关近缘物种的全基因组测序提供一定的理论指导;同时,我们对两个材料的基因组进行了de novo拼接,获得的序列信息可以为分子标记的开发及基因挖掘提供数据参考。研究结果表明:映山红与皋月杜鹃的基因组大小分别均在608 Mb和567 Mb;它们都具有很高的杂合度,其中,映山红杂合度约在1.9%,皋月杜鹃杂合度约在2.6%;因为两个材料的杂合度均很高,且它们的自交亲和性差,极难获得相对纯合的材料,建议后期在对它们进行全基因组测序时,应优先采用大片段的三代测序手段,利用二代测序进行Hi-c的辅助组装及错误较正,并结合bionano光学图谱技术,有望得到较好的结果。

The Rhododendrons share very h igh ornamental value because of its colorful flowers and luxuriant foliage, it is bright as a brocade cloud and also known as the "king of woody flowers". The wild Rhododendron resources have a wide geographical distribution in the world, 566 species are distributed in China, which is the diversified center of Rhododendron germplasm resources. Through the high-throughput sequencing technology, We first determined the genomes of Rhododendron simsii and Rhododendron indicum by studying the highthroughput sequencing of two rhododendra germplasm resources. Then we estimated the genomic information such as heterozygosity, GC content, and repeatability of these two materials by using bioinformatics methods, to provide some theoretical guidance for the whole genome sequencing of related species. At the same time, we de novo assembled the genomes of two materials, the obtained sequence information could provide a certain basis for the development of molecular markers and gene mining. The results showed that the genome sizes of R. simsii and R. indicum were 608 Mb and 567 Mb, respectively;they both have high heterozygosities, of which, the heterozygosity rate of R. simsii was about 1.9%, while the heterozygosity rate of R. indicum was about 2.6%.Because the heterozygosity rate of both materials were extremely high, and self-compatibility was often poor, thus it was hard to obtain relatively homozygous materials. It is suggested that in the later stage of genome sequencing, priority should be given to the third generation sequencing of large fragments. The auxiliary assembly and error correction of Hi-c were carried out by using second generation sequencing, and a good result are expected to be obtained by combining with bionano optical atlas technology.