Ten Bacterial Artificial Chromosome Sequences Reveal the Genome Characteristic and Structure of Panax ginseng

Most plant genomes generally have plenty of repetitive elements and vestige of polyploidy which make the structure more complex. These complicated factors are giving a lot of difficulties on elucidate the exact genome structure. Panax ginseng is a well-known valuable medicinal plant with excellent pharmacological effects, however its complex genomic structure has not been elucidated. To understand its genome structure, we characterized ten bacterial artificial chromosome (BAC) sequences. Small-scale genome corresponding to total 1,163,364 base pair was generated through single molecule real-time sequencing platform producing long reads. Nine BAC sequences were immaculately assembled in complete form except the one that divided into two fragments. By careful analyzing assembled sequences, we have identified that the 87.4% region of BAC sequences were composed of diverse repetitive elements which have complex insertion patterns and the large fraction of those regions (46.9%) were occupied by Ty3/Gypsy family of long terminal repeat retrotransposons(LTR-RTs). Moreover, the six intact LTR-RTs which have not reported in previous studies were newly detected and confirmed the inner architectures. Eleven protein-coding genes were identified in the remaining 12.6 % unique regions. This results demonstrate that utilization of long reads is possible to overcome existing limitations that occur to the research plants with complex genome. The knowledge generated through this study provides various resources for understanding of ginseng genome and facilitates related analysis by serving the multiple approaches. This work was carried out with the support of "Cooperative Research Program for Agriculture Science & Technology Development(PJ01103001)" Rural Development Administration, Republic of Korea.