Flower color is one of the key trait that determines the marketability of chrysanthemums. However, genetic research on chrysanthemum remains limited because of numerous environmental factors and the complexity of the chrysanthemum genome. To gain a deeper understanding of the genetic mechanisms underlying flower color in chrysanthemum, this study conducted genotyping analysis on 94 F₁ progenies derived from a cross between two wild chrysanthemum parents, ‘CWT2’ and ‘CWT8,’ which exhibit distinct flower colors. Genotyping-by-sequencing (GBS) was used for SNP identification, resulting in 79,002 single nucleotide polymorphisms (SNPs). After stringent filtering, 2,548 SNP markers were selected to construct a GBS-SNP linkage map, which was subsequently used to detect quantitative trait loci (QTLs) associated with flower color. Four QTL were identified, encompassing genes involved in carotenoid biosynthesis, carotenoid degradation, and the methylerythritol phosphate pathway. Among the 16 candidate genes analyzed for their potential role in flower color determination, three genes (VDE, CYP707A4, and CYP707A2) were ultimately selected for molecular marker development. The findings of this study provide a valuable foundation for understanding the genetic basis of carotenoid degradation in chrysanthemums. Future in-depth research is expected to facilitate the development of new chrysanthemum varieties for breeding programs through marker-assisted selection in breeding programs.

Chrysanthemum is the most popular ornamental plant, after roses and lilies. The cauliflower mosaic virus (CaMV) promoter, which remains the most widely used promoter in dicotyledons, is a very strong promoter with sufficient effects in most crops. However, weak expression has often been reported in Chrysanthemum. Therefore, we searched for constitutive promoters available in Chrysanthemum. Based on the transcriptome analysis data of Chrysanthemum, nine constitutively expressed genes were selected, and each promoter region (1.0–3.0 kb) was isolated by genome walking. Only two of the nine promoters expressed GUS in tobacco and chrysanthemums. The major motif of the CmERF promoter (U41, 2060 bp) was related to the regulation of ethylene (ERELEE4) or gibberellin (PYRIMIDINEBOXOSRAMY1 and WRKY71OS). Similarly, the motif of the CmGA2 ox promoter (U47, 1060 bp) also contained gibberellin signaling factors, such as PRIMIDINEBOXHVEPB1 and WRKY71OS. Both promoters showed strong systemic expression in tobacco using GUS staining. Although weaker than in tobacco, significant expression was confirmed in the flowers and stems in chrysanthemum. The results of the GUS activity assay using chrysanthemum transformants showed that the transgenic line (#12) containing the U47 promoter had higher expression in all tissues than that containing the 35S-CaMV promoter. The U41 promoter was found to have a higher expression than the 35S-CaMV promoter in the stem.

Fruit development period (FDP), defined as the time between full bloom and maturity, varies greatly in peaches (Prunus persica L. Batsch). It is necessary to develop molecular markers associated with maturity date to extend the harvest season in new peach cultivars. We designed the 260 SSR primer set covering the entire genome of approximately 300 kb to 1 Mb based on P. persica cultivar ‘Mihong’ genome sequence. The SSR markers were used to survey the relationship between the parentages ‘Yumeyong’ and ‘Chiyomaru’ and their offspring cultivars ‘Mihong’, ‘Yumi’, ‘Misshong’ and ‘Soomee’. Male cultivar ‘Chiyomaru and its offspring cultivars ‘Mihong’, Yumi’, and ‘Misshong’ are early and middle maturity cultivars with FDP of 77, 76, 82, and 108 days, respectively, whereas female cultivar ‘Yumyeong’ and its offspring cultivar ‘Soomee’ are late maturity cultivars with FDP of 128 days. Three regions of SSR markers could distinguish between early, middle, and late maturity cultivars. In the early stages of breeding, these markers will be used for marker-assisted selection (MAS) in the parentages ‘Yumyeong’ and ‘Chiyomaru’ and their offspring cultivars.

Prunus persica “Mihong” cultivar is a domesticated white peach that was generated from the crossing between “Yumyeong” and “Chiyomaru” cultivars in the Republic of Korea in 1995. We launched “Mihong” genome sequencing in 2018 and “Mihong” reached to 200 scaffold and 241 Mb sequences using long-read sequencing and Hi-C technology. F₁ populations of ”Kawanakajima Hakuto,” “Mihong,” “Changhowon Hwangdo,” and “Yumi” were developed in NIHHS. These four cultivars were sequenced and assembled using the SOAPdenovo version 2.04. First, we surveyed the SSRs in “Mihong” assembly sequences and extracted the ±300 bp flanking sequences containing SSRs. Second, the assembly sequences of three cultivars were aligned and mapped against “Mihong” ±300 bp flanking sequences using BLASTn (version 2.2.29+). We anticipated the differential length in SSRs among the four cultivars. We sorted the primers with a standard deviation over 4.5 (STEV > 4.5) among the four cultivars. In addition, we surveyed the primers having difference in over 10 bp with “Kawanakajima Hakuto” and “Mihong” for polymorphic markers in the mapping population. All primer pairs were designed to generate amplicons of 150-200 bp in coating SSR regions using primer3 (version 3-2.2.3). We selected 260 SSR markers with a physical distance of average per 1 Mb. These SSR markers accounted for 74% polymorphism in the four genotypes. Finally, a F₁ population of “Kawanakajima Hakuto” and “Mihong” covered 884.5 cM with 465 SNPs and 86 SSRs and this genetic map matched correctly to the HI-C pseudomolecule of P. persica.

Amphidiploid Brassica juncea (AABB, 2n=36) contains the synthesized genome of the diploid ancestors of Brassica rapa (AA, 2n=20) and Brassica nigra (BB, 2n=16), proven the ‘triangle of U’ model. Varieties of the B. juncea include vegetables, oilseed crops, and medicinal plants in South Asia, China, and other regions. ‘Dolsangat’, one of the cultivars of B. juncea is widely used as the main ingredient for ‘KatKimchi’, a kind of Korean traditional food Kimchi. To develop an efficient polyploidization protocol of B. juncea, we used twenty accessions. Among them, we could induce the amphidiploid plants with 0.23% in natural. A successful of polyploidization, it is essential of chromosome doubling regent treatment of B. juncea. At first, we tried to colchicine treatment in the embryo stage and it was very harmful to the embryo and could get few plants. The second, we made the regeneration plants from embryo to rooting phase and shocked them in 0.34% colchicine contained distilled water. We could induce amphidiploid plants with a success rate of 63.4%. Also, we surveyed glucosinolate content and JB1, Alsami, and JD6 showed high total contents. These plants will use for genetic materials for breeding, genetic and molecular studies.

High-density genetic linkage mapping is critical for undertaking marker-assisted selection and confirming quantitative trait loci, as well as helping to build pseudomolecules of genomes. We constructed a genetic map using 94 F₁ populations generated from the interspecific cross between Korean cultivar “Wonwhang” (Pyrus pyrifolia, NCBI BioSample SAMN05196235) and European cultivar “Bartlett” (Pyrus communis). We designed a total of 24,267 SSR markers based on the genome sequences of “Wonwhang” for this. To select the markers that are linked to the traits important in pear breeding programs, SSR-containing genomic sequences were subjected to nucleotide sequence homology searches, which resulted in 510 SSR markers with high similarity to genes encoding proteins with putative functions such as transcription factors, resistance proteins, flowering time, and regulatory genes. Of these, 70 markers showed polymorphisms in parents and segregating populations and were used to construct a genetic linkage map, together with the unpublished 579 SNPs obtained from genotyping by sequencing analysis. The genetic linkage map covered 3,784.2 cM and the average distance between adjacent markers was 5.8 cM. Seventy SSR markers were distributed across 17 chromosomes with more than one locus.

Genetically modified (GM) crops have been developed worldwide through the recombinant DNA technology and commercialized by various agricultural biotechnology companies. Commercialization of GM crops will be required the assessment of risk associated with the release of GM crops. The purpose of this research is a molecular characterization of introduced T-DNA in transgenic rice T4~T6 generation lines harboring a pepper MsrB2 gene under the control of stress inducible Rab21 promoter, as a part of biosafety evaluation for drought-tolerant transgenic rice (Agb0103). We identified the structure and sequence of transformation vector of T-DNA and analyzed insertion sites, flanking sequences, and generational stability of inserted T-DNA in transgenic rice lines. The transformation vector was consisted of right border, a drought-tolerant CaMsrB2 gene unit (Rab21 promoter:CaMsrB2:PinII terminator), a selectable marker herbicide resistance unit (CaMV 35S promoter:bar:Nos terminator), and left border in sequential order. Based on the adaptor-ligation PCR and whole genome sequence database, we confirmed that T-DNA was introduced 2 copies (head to head type) at the position of 2,471,957∼ 2,472,049 bp of chromosome No. 8. From the generational stability study, T-DNAs were stably inherited through the T4 to T6 generations, and also stable expression of bar gene from T-DNA was confirmed. It was also confirmed that the backbone DNA of transformation vector containing antibacterial gene was not present in Agb0103 rice genome. These results will be filed to biosafety assessment document of Agb0103.