The generation and analysis of genomic resources information are essential to understand genomic features of crops. Even though medicinal component and its effect of Panax ginseng was well studied, the genomic study has been recently started. The ginseng genome has been known to undergo two rounds of whole genome duplication (WGD), therefore we investigated an evidence of WGD in ginseng draft sequence for understanding current ginseng genome structure. Four paralogous gene-rich genome blocks were found, consisted by eight scaffolds, using about 3.0 Gb whole genome draft sequence and 48,821 unigenes of P. ginseng generated by whole genome shotgun sequencing. The eight scaffold sequences were ordered and connected into four genomic blocks, using zig-zag extension within scaffold sequences recently duplicated. The paralogous scaffold pairs that were recently duplicated showed high sequence conservation in genic and non-genic regions. However, paleo duplicated paralogue scaffold sequences showed little conservation only in genic regions. Finally, a total of 110 paralogous gene pairs and its expression were identified from recently and paleo duplicated scaffold pairs, which were co-linear among four genomic blocks. This study provides the first insight into duplicated genome structure of ginseng and will be a valuable information for further ginseng genomics including improvement of draft sequence quality, chromosome anchoring of scaffolds, and genetic mapping.

Clubroot is a devastating disease caused by Plasmodiophora brassicae and results in severe losses of yield and quality in Brassica crops including Brassica oleracea. Therefore, it is important to identify resistance gene for CR disease and apply it to breeding of Brassica crops. In this study, we applied genotyping-by-sequencing (GBS) technique to construct high resolution genetic map and mapping of clubroot resistance (CR) genes. A total of 18,187 GBS markers were identified between two parent lines resistant and susceptible to the disease, of which 4,103 markers were genotyped in all 78 F2 plants generated from crossing of both parent lines. The markers were clustered into nine linkage groups spanning 879.9 cM, generating high resolution genetic map enough to refine reported reference genome of cabbage. In addition, through QTL analysis using 78 F2:3 progenies and mapping based on the genetic map, two and single major QTLs were identified for resistance of race 2 and race 9 of P. brassicae, respectively. These QTLs did not show collinearity with CR loci found in Chinese cabbage (Brassica rapa) but roughly overlapped with CR loci identified in cabbage for resistance to race 4. Taken together, genetic map and QTLs obtained in this study will provide valuable information to improve reference genome and clubroot resistance in cabbage.

Tongil (IR667-98-1-2) rice, developed in 1972, is a high-yielding rice variety derived from a three-way cross between indica and japonica. Tongil contributed to staple food self-sufficiency of Korea, an achievement that was termed the ‘Korean Green Revolution’. In this study, we analyzed the nucleotide-level genome structure of Tongil rice and compared it to those of the parental varieties. A total of 17.3 billion Illumina Hiseq reads, 47× genome coverage, were generated from Tongil rice. Three parental accessions, two indica and one japonica types, of Tongil rice were also sequenced for approximately 30x genome coverage. A total of 2,149,991 SNPs were detected between Tongil and Nipponbare; the average SNP frequency of Tongil was 5.77 per kb. Genome composition based on the SNP data by comparing with the three parental genome sequences on sliding window of Nipponbare genome sequence revealed that 91.8% of the Tongil genome originated from the indica parents and 7.9% from the japonica parent, different from the theoretical expectation in a three-way cross, i.e., 75% indica and 25% japonica parental origins on average. Copy number of SSR motifs, ORF gene distribution throughout the whole genome, gene ontology (GO) annotation, yield-related QTLs or gene locations, and polymorphic transposon insertions were also comparatively analyzed between Tongil and parents using sequence-based tools. The results indicated that each genetic factor was transferred from parents into Tongil in proportion to the whole-genome composition. The Tongil rice is the first successful superior cultivar derived from indica × japonica hybridization in Korea. Defining of genome structure demonstrates that the Tongil genome is composed mostly of the indica genome with a small proportion of japonica genome introgression. This work was supported by a grant from the Next-Generation BioGreen 21 Program (Plant Molecular Breeding Center No. PJ008125), Rural Development Administration, Republic of Korea.

Genetic map provides basic and important informations for breeding. Therefore, genetic map construction is a essential process in plant research. Panax ginseng is one of the most famous medical plant in the world. However, genetic informations of this medical plant for breeding are not enough. Because of little informations, genetic map construction of panax ginseng provides very useful information for breeding. Using Solexa next generation sequencing (NGS) technology, we have been produced a lot of expressed sequence tags (ESTs) and whole genome sequences from Chunpoong (368 Gb) and Yunpoong (6 Gb) cultivar. To develop large amount of DNA markers and thus construct high resolution genetic map, we inspect large scale of SSR motif and putative SNP sites which can be used as dCAPs markers using produced ginseng’s sequence data. As a result, we can find a number of DNA markers that have polymorphism between Yunpoong and Chunpoong cultivar. These developed DNA markers were analyzed for F2 population of Yunpoong x Chunpoong to find markers showing Mendelian segregation ratio 1:2:1.