This study was carried out to compare the survival and mutation rates and mutation spectrum by gamma-irradiation on rooted and unrooted cuttings of three spray type (‘Lovelydia’, ‘Yellowbabe’, and ‘Haetsal’) and two standard type (‘Vital’ and ‘Aqua’) cultivars in roses. Two groups, rooted and unrooted cuttings were gamma-irradiated at 70Gy for 24 hours. The irradiated rooted and unrooted cuttings were planted in a greenhouse, and survival, mutation rates and mutation spectrum were investigated 30 weeks after planting, respectively. As a result, survival and mutation rates ofgamma-ray irradiated plants were 16.4%~50.8% and 0~5.1% for unrooted cuttings, and 39.4%~55.1% and 0.7%~7.4% for rooted cuttings, respectively. In conclusion, both survival and mutation rates were a little higher on rooted cuttings than on unrooted cuttings. However, when only survived plants after gamma-ray irradiation were considered, mutation rates were 0~10% and 1.8%~14.1% for unrooted cuttings and rooted cuttings, respectively, showing no significant difference. In addition, diverse variations on color and number of petals or shape of flowers were detected both in plants from rooted and unrooted cuttings, which indicated that there was no significant difference in mutation spectrum between two groups.

Capsinoids, low-pungent compounds, have the same biological effects as capsaicinoids such as anticancer and anti-obesity. A precursor of capsinoids, vanillyl alcohol, is known to be produced by mutations in the putative-aminotransferase (pAMT) gene. In the previous study, ‘SNU11-001’ (Capsicum chinense) containing high levels of capsinoids was identified in germplasm collections of Capsicum. This collection has a unique mutation in the pAMT gene that can cause dysfunction of this gene. In order to develop pepper varieties containing high capsinoids contents, marker-assisted foreground and background selections were performed during backcross breeding. Compared to the conventional backcrossing, marker-assisted backcrossing (MABC) is extremely useful for recovery of a recurrent parent’s genetic background. For foreground selection, plants carrying the pAMT/pamt genotype were selected from a BC1F1 and BC2F1 populations using SCAR markers derived from the unique pAMT mutation of ‘SNU11-001’. To obtain background selection markers, a total of 412 single nucleotide polymorphism (SNP) markers was screened on ‘Shinghong’ parental lines and ‘SNU11-001’ to obtain polymorphic SNP markers. Of the 412 SNP markers, 144 and 204 polymorphic SNP markers evenly distributed in pepper genome were finally selected. BC1F1 and BC2F1 plants carrying the pAMT/pamt genotype were subjected to background selection using the selected marker sets. Multiple genotype analysis was done using a high-throughput genotyping system (EP1TM, Fluidigm®, USA). As a result, one BC1F1 plant 84% similar to the recurrent parent and several BC2F1 plants more than 96% recovery rate of the recurrent parent were selected. Genetic backgrounds of the selected BC2F1 plants were evaluated by the genotype-by-sequencing (GBS) method in order to confirm the background selection results using the SNP marker set. GBS results showed that recovery rate and positions of introgressed segments were well matched between two methods demonstrating MABC can be successfully done with a couple hundred SNP markers.

Space has many distinguishable characteristics from earth such as strong cosmic radiation, microgravity, supervaccum and weak magnetic field. For this reason, space environments can be used an efficient mutagen for plant breeding nowadays. To identify the affected genes by condition in space with outer space, Brachypodium seeds were placed in the Russia Segment (RS) Biorisk module of International Space Station (ISS). Brachypodium distachyon is a model system for temperature grass, because they represent the characteristics for annual winter grass. Seeds and organs of plants carried by satellite or spacecraft to space can be genetically mutated by exposing space environment. We performed a duplicated RNA sequencing to profile the differentially expressed genes. As a results, about 700 genes were upregulated and 250 genes were downregulated by cosmic environments, respectively. In the molecular function category, protein kinase and transcription activity related genes were upregulated. Among the many transcription factors (TFs), stress related TFs such as ERF, NAC and WRKY were differentially expressed in space exposed samples. In the future, their expression will be identified by using qRT_PCR.

sy-2 (Seychelles-2) is a temperature sensitive natural mutant of Capsicum chinense and native to Seychelles Island in Africa. Previously we showed that sy-2 leaves were irregularly shaped and defective in chlorophyll development at temperatures below 24℃. A segregation test revealed that the sy-2 gene is controlled by a single recessive gene. To identify the sy-2 gene, we performed a map-based cloning approach using a total 600 individual F2 plants derived from crossing sy-2 and the wild type C. chinense ‘No.3341’. Fine-mapping of the locus allowed us to position sy-2 to an approximately 170-kb region flanked by markers IN2-1-1 and SNP-3-7 on chromosome 1. Among the approximately 36 hypothetical genes in this region several candidate genes including: HSP90-like ATPase family proteins, lipid-transfer proteins, calmodulin-domain protein kinases, and zinc finger proteins (ZFPs) were identified. RT-PCR and sequencing of the hypothetical genes are under way to identify sy-2.

Rose (Rosa Hybrida Hort.) are of a high symbolic value and a great cultural importance in different societies. They are widely used as garden ornamental plants and as cut flowers. For the induction of mutation, gamma-rays are widely used as a mutagen. This study was carried out to establish a system for mutation breeding by irradiation of gamma-ray in rose. The rooted cuttings of five cultivar roses (Lovelydia, Vital, Aqua, Yellowbabe and Haetsal) are grown by in a greenhouse. They were two difference treatment (Before rooting gamma-ray irradiation, After rooting gamma-ray irradiation) were exposed to dose of 70 Gy using a 60Co gamma-irradiator (150 TBq of capacity ; ACEL, Canada) at the Korea Atomic Energy Research Institute. The irradiated plants were planted in a greenhouse, and investigated survival rate, mutation rate, flower buds number, and shoot length were planted after 80days. The two treatments of and growth characters was significantly reduced to 20% to 40% compared with the control. In addition, survival rate and mutation rate were ‘after rooting γ-ray irradiation (37.4~67.3% and 0.5~5.6%)’ higher than ‘before rooting γ-ray irradiation (18.3~50.8% and 0.3~3.4%)’. Mutation types were solid type, chimeric and mosaic petal mutants with various colors were induced from five rose. These results indicate that efficiency of mutation induction in rose by gamma-ray irradiation on petal colors and petal shapes in two difference treatment with rooted cutting system.

To define whole genome-level of structural variation by ionization energies and radiation doses in plant, the seeds of Ilpum rice cultivar were acutely irradiated with gamma rays (100Gy, 200Gy, and 400Gy) and ion-beams (20Gy, 40Gy, and 80Gy), respectively. Six M1 rice plants were re-sequenced by Hi-Seq2500 with Ilpum cultivar as control. The average sequencing coverage of the individuals was 10.6X, and the average mapping rate to the rice reference genome (IRGSP-1.0) sequence was 96.95%. The individual plants were irradiated with gamma-400Gy and ion-50Gy had highest variation of SNP with 471,837 and 469,147, respectively. The number of insertion/deletion was 77,500 and 77,106, the synonymous and frame-shift were 7,859 and 7,763 in above two individuals. Although high genome variation shown between Ilpum cultivar and irradiated individuals, there were non-correlation between number of variation and radiation doses. However, five individuals, except ion-20Gy, showed 33 common variant blocks (CVBs) spanning 6 Mb in whole rice genome (1.6%). The CVBs were distributed on 12 rice chromosomes, Chromosome 6 had biggest CVB (5 blocks, 1.3Mb), whereas chromosome 9 had smallest CVB (0.01Mb). Total five hundred fifty one genes were in CVBs which can regard radiation sensitive genes or may be regarded as radiation hot spots in rice genome. This study will contribute to the improvement of the radiation mutation breeding research in genetic and genomic aspect.

Radiation technologies have been widely used in mutation breeding of crops. Although gamma-radiation has been predominantly applied in radiation breeding, ion beam irradiation is recently emerging as a methodology highly effective in induction of mutations that are useful for plant breeding. Therefore, we investigated the biological effects caused by irradiation of two types of ion beams, which were proton and ion beams, respectively, in pepper. In the evaluation of survival rate, LD50 values were between 300 and 350 Gy, 30 and 40 Gy in irradiation of proton and carbon beams, respectively, while LD50 for gamma-ray was determined to be between 50 and 100 Gy. Growth traits including shoot length, root length, and root width were also examined in pepper seedlings according to does of proton and carbon ion beams to estimate biological effectiveness of each radiation. The result was applied in the construction of pepper mutant population which will be used to develop pepper breeding materials containing novel characteristics.

Capsinoids, low-pungent compounds, have the same biological effects as capsaicinoids such as anticancer and anti-obesity. A precursor of capsinoids, vanillyl alcohol, is known to be produced by mutations in the p-aminotransferase (p-AMT) gene. In the previous study, SNU11-001 (C. chinense) containing high levels of capsinoids was found in germplasm collections of Seoul National University. We found that this collection has a unique mutation in the p-AMT gene. In order to develop a cultivar containing high capsinoids contents, marker-assisted foreground and background selection were performed in this study. Backcrossing is an effective breeding method for introducing useful traits to an elite cultivar. Compared to conventional backcrossing, marker-assisted backcrossing (MABC) is extremely useful for recovery of a recurrent parent’s genetic background. To obtain background selection markers, a total of 412 single nucleotide polymorphism (SNP) markers was screened to obtain polymorphic SNP markers between ‘Takanotsume (C. annuum)’ and ‘SNU11-001’. Of the 412 SNP markers, 96 polymorphic SNP markers evenly distributed in pepper genome were finally selected. Plants carrying the pAmt/pamt genotype were selected from a BC1F1 population using SCAR markers derived from the unique p-AMT mutation of SNU11-001. BC1F1 plants carrying the pAmt/pamt genotype were subjected to background selection. Multiple genotype analysis was done using Fluidigm platform (BioMark). Once we obtain plants carrying most similar genetic background to recurrent parent, capsinoids contents will be measured and another round of MABC be done to obtain plants containing high levels of capsinoids.

sy-2 (Seychelles-2) is a temperature sensitive mutant of Capsicum chinense and native to Seychelles Island in Africa. Previously we showed that sy-2 leaves were irregularly shaped and defective in chlorophyll development at temperatures lower than 24℃. A segregation test revealed that the sy-2 gene is controlled by a single recessive gene. To identify the sy-2 gene, we performed a map-based cloning approach using a total of 1,010 F2 plants derived from crossing sy-2 and the wild type C. chinense ‘No.3341’. sy-2 gene is located on chromosome 1, 0.3 cM and 0.1cM away from cosII markers C2_At4g29120 and C2_At1g09070, respectively. The tomato genome sequence between those two markers was compared with pepper genome sequence. We found three of pepper scaffold sequences in this region. We developed seven ingle nucleotide polymorphism (SNP) markers on the pepper scaffold sequences, among which five SNP markers were co-segregated with sy-2. To fill the gap between the scaffolds which contains co-segregating markers, we screened a bacterial artificial chromosome (BAC) library, and end-sequences of total of 22 AC clones were i. We found that five clones were overlapped to cover the gap. We fully sequenced four AC clones and found that the physical distance between C2_At4g29120 and C2_At1g09070 is 343kb. This region contains 70 putative genes such as HSP90-like ATPase family proteins, lipid-transfer proteins, calmodulin-domain protein kinases, and zinc finger proteins (ZFPs). To identify the sy-2 gene, we performed RT-PCR and found that a ZFP-like gene is differentially expressed between WT and sy-2 leaves. This result suggests that the ZFP-like gene is a strong candidate for the sy-2 gene. We are currently characterizing this candidate gene.

Capsinoids, low-pungent compounds, have the same biological effects as capsaicinoids such as anticancer and anti-obesity. A precursor of capsinoids, vanillyl alcohol, is known to be produced by mutations in the p-aminotransferase (p-AMT) gene. In the previous study, SNU11-001 (C. chinense) containing high levels of capsinoids was found in germplasm collections of Seoul National University. We found that this collection has a unique mutation in the p-AMT gene. In order to develop a cultivar containing high capsinoids contents, marker-assisted foreground and background selection were performed in this study. Backcrossing is an effective breeding method for introducing useful traits to an elite cultivar. Compared to conventional backcrossing, marker-assisted backcrossing (MABC) is extremely useful for recovery of a recurrent parent’s genetic background. To obtain background selection markers, a total of 412 single nucleotide polymorphism (SNP) markers was screened to obtain polymorphic SNP markers between ‘Takanotsume (C. annuum)’ and ‘SNU11-001’. Of the 412 SNP markers, 96 polymorphic SNP markers evenly distributed in pepper genome were finally selected. Plants carrying the pAmt/pamt genotype were selected from a BC1F1 population using SCAR markers derived from the unique p-AMT mutation of SNU11-001. BC1F1 plants carrying the pAmt/pamt genotype were subjected to background selection. Multiple genotype analysis was done using Fluidigm platform (BioMark). Once we obtain plants carrying most similar genetic background to recurrent parent, capsinoids contents will be measured and another round of MABC be done to obtain plants containing high levels of capsinoids

Capsinoids which were found recently in non-pungent pepper show the same biological effects as capsaicinoid including anticancer and anti-obesity. A precursor of capsaicinoids, vanillyl alcohol, is known to be produced by mutations in the p-aminotransferase (pAMT) gene. In the previous study, we showed that capsinoid production is also controlled by the capsaicin synthase (CS) gene. However correlation between the CS gene expression and capsinoids contents has not been fully understood. This study was conducted to elucidate correlation between the expression level of CS gene and capsinoids contents. Through germplasm screening, we identified one C. chinese pepper cultivar, SNU11-001, which contained capsinoids as much as C. annuum ‘CH-19 Sweet’. SNU11-001 was crossed with five Capsicum cultivars (ECW, Takanotsume, Yuwolcho, Habanero and Jolokia) containing different levels of capsaicin, ‘ECW’ is non-pungent pepper line, and ‘Takanotsume’ and ‘Yuwolcho’ have mild pungency, and ‘Habanero’ and ‘Jolokia’ is known to be included in the most pungent pepper lines. When we analyzed the expression of CS and pAMT genes using the six Capsicum cultivars, the expression levels of CS were higher in pungent Capsicum cultivars. To test whether the expression levels of CS also control capsinoids contents, we will analyze several F2 populations derived from crosses between SNU11-001 and Capsicum cultivars containing different levels of capsaicin.