Copy number variations (CNVs) are considered major sources of genetic variation, and CNVs may influence phenotypic variation and gene expression. To detect CNVs, rice seeds were exposed with 100～400 Gy of gamma-ray (GA, 60Co), cosmic-ray (CR) by Russia ISS, and 30 and 40 Gy of ion beam (IB, 220 Mev carbon ion). After the exposed rice seeds were cultured in 1/2 MS medium for 14 days, they were used for array-based Comparative genomic hybridization (CGH) analysis using Agilent’s RICE CGH array. As a results, the highest number of CNVs (Gain 808 and Loss 24,080) were detected in the CR treatment, whereas GA100 (100 Gy of GA) was identified the least CNVs. Compared individual chromosome, the chromosome 8 and 11 were identified the highest CNVs, the chromosome 3 had the least CNVs. Most of identified CNVs existed in the range of 10～500kb. In particular, the same CNV locations among different types of ionizing radiation were observed in chromosome 12, and these CNVs contained the commonly 5 amplified genes, containing retrotransposon protein, NADH-ubiquinone oxidoreductase chain 3, heavy metal transport/detoxification protein domain containing protein, and 2 unknown proteins. Other studies were reported that Ty1 (Long Terminal Repeat-retrotransposon family 1) transcription and retrotransposition were induced by different environmental stresses such as ionizing radiation, UV-light exposure, DNA damage and nutrient starvation in Saccharomyces cerevisiae. Our results also show that retrotransposon protein (LOC_Os12g34016) was specifically amplified by different types of ionizing radiation.

VitE (tocotrienols and tocopherols) are micronutrients with antioxidant properties synthesized by photosynthetic bacteria and plants that play important roles in animal and human nutrition. A new mutant line, T1001-1, was isolated from in vitro mutagenized population by ionizing radiation and shown to have increased VitE contents. The total VitE content was 26% increased in the T1001-1 mutant seeds compare with cv. Dongan (wild-type). In addition, we showed that the mutant confers retarded seedling growth during the early seedling growth stage in rice. To study the molecular mechanism of VitE biosynthesis, we used the rice microarray to identify genes that are upor down-regulated in T1001-1 mutant. In addition, we identified differentially regulated pathway using MapMan analysis, which provides deep insight into changes in transcript and metabolites. Our results enhanced the transcription of genes involved in starch and lipid metabolism in T1001-1 mutant. To identify the molecular mechanisms of the events involving transcription factors in tocopherol accumulation, we compared the expression patterns of transcription factors. The AP2-EREBP, WRKY, C2H2 transcription factor were up-regulated, whereas the MYB family was down-regulated in T1001-1 mutant. Our results demonstrate change of important transcript in high level of VitE accumulating rice mutant.

To determine the expression levels of genes related to the salt stress response in rice, gene expression profiles were investigated through microarray analysis using the rice mutant line Till-II-877. There were no significant changes in physiological response under salt stress of the mutant increased less than that in the WT. The intensity of gene expression was analyzed and compared between the wild type and mutant lines using a microarray. Among the most significantly affected pathways, α-linolenic acid metabolism and linoleic acid metabolism (in lipid metabolism), fructose and mannose metabolism and glycolysis-gluconeogenesis (in carbohydrate metabolism), cysteine and methionine metabolism (in amino acid metabolism), and carbon fixation (in the energy metabolism of photosynthetic organisms) showed changes in gene expression levels under salt stress. These results further our understanding of the effects of salt stress in rice and may aid in the development of salt-tolerant rice cultivars.

Soluble sugar content in soybean seed is an important quality attribute for soyfood and feed. Usually, soluble sugars comprise 6 to 17% of total dry wt. in mature soybean seeds. In this study, 414 soybean mutant lines induced by gamma-ray were screened by colormetric assay, FACE (Fluorophore-assisted carbohydrate electrophoresis), and GC-MS to identify the change of soluble sugar contents. Among 414 soybean mutant lines, 12 mutant lines derived from three different soybean cultivars (Hwanggum, Paldal, and Bangsa) showed higher level of soluble sugar content compared to their original cultivars. However, 5 mutant lines derived from soybean landrace KAS 636-15 showed lower level in the colormetric assay. In FACE, 17 soybean mutant lines selected by colormetric assay also showed different band intensity compared with their original cultivars. However, there were no different soluble sugar patterns between soybean original cultivars and mutant lines. Finally, the variations of soluble sugar content in 17 soybean mutant lines were confirmed by using GC-MS. These mutant lines will be used for genetic study to find mutations of genes related soluble sugar biosynthesis.

Ionizing radiation is known to cause chromosomal alterations such as inversions and deletions and affects gene expression within the plant genome. To monitor the genome-wide transcriptome changes by ionizing radiation, we used rice Affimetrix GeneChip microarray to identify genes that are up- or down regulated by gamma-ray (200 Gy, 60Co source), cosmic-ray and ion beam (40 Gy, 220 MeV carbon ion). The overall expression patterns between gamma-ray and ion beam were similar but cosmic-ray was regulated differently. Combined results from all 3 radiations identified 27 up-regulated genes and 188 down regulated genes. These results mean the induction of similar mechanism changes in treatments of gamma ray and ion beam. However the different expression in treatment of cosmic-ray might be due to the other environmental conditions. Among the commonly up- or down- regulated genes, we chose highly up- or down- regulated several genes and confirmed its regulation in response to ionizing radiation exposure by RT-PCR analysis. Moreover, we showed that specific co-expression networks of candidate radio marker genes by ARACNE algorithm. Our results present profiles of gene expression related to different ionizing radiation and marker gene to predict sensitivity to ionizing radiation, such as GS (glutelin subunit) and FBX322.

A dietary deficiency of tryptophan can cause pellagra and lead to low levels of serotonin that is associated with depression, aggression, anxiety and overeating in humans. Thus, enhancement of tryptophan content in rice has great potential benefit for human and animal diets. In this study, a total of 1,350 rice mutant population was used to identify single nucleotide polymorphisms (SNPs) in Oryza sativa anthranilate synthase alpha1(OASA1) gene that was associated with negative feedback in tryptophan biosynthesis. For high-throughput TILLING analysis, 5 fluorescence-labeled primer sets were designed to cover exon regions of OASA1 locus and PCR amplifications were analyzed using ABI3130xl DNA sequencer. Through the screening of 1,350 mutant lines, nine mutant lines produced one or two cleaved fragments in the PCR products of OASA1 locus. The full sequencing of nine mutant lines revealed that total 31 SNPs were located in the regions of OASA1. In particular, three mutant lines contained SNPs in coding regions that resulted in an amino acid change. The tryptophan contents of the three mutant lines were 2.2- to 2.3-fold higher than the wild type. These high-tryptophan mutant lines will be used rice breeding programs and contribute directly to enhancing human nutrition.

Kenaf (Hibiscus cannabinus) is an annual herbaceous plant of the family Malvaceae that has been planted in Africa for more than 4000 years and used as source of fiber, energy and feed stock. Also, kenaf seeds are good source for edible oil used for first class cooking oil and margarine production. The seeds can be used for lubrication, soap, paint and varnishes. This study was carried out to evaluate fatty acids variation among sixteen kenaf germplasm and gamma-ray induced mutants derived from Jinju and Auxu. Linoleic, oleic, and palmitic acid were the predominant fatty acids in all kenaf seed oils. The sixteen accessions showed a wide range of fatty acid compositions, spanning from 28.94 to 43.36% saturated, 56.64 to 71.05% total unsaturated, 15.52 to 46.85% monounsaturated, and 13.56 to 48.97% polyunsaturated fatty acids. The mutant lines derived from Jinju, significantly surpassed parental mean for all the palmitic and oleic acid. Also, the mutant lines derived from Auxu showed broad ranges of variation in oleic and linoleic acid and narrow ranges of variation in stearic and palmitic acid. The relative amount of monounsaturated fatty acids (MUFA) were increased at all the gamma-ray induced mutants. These results will provide a valuable information to assist parental selection of kenaf breeding.

We bred a new green-kerneled glutinous rice variety that can be cultivated in the whole area of Korea, because only one native green-kerneled glutinous rice cultivar, “aengdongchalbyeo” has been cultivated in the southern coastal area due to its late heading. The seeds of “aengdongchalbyeo”were irradiated with 200 Gy of gamma ray in 1995. A promising mutant variety, “ogwonchalbyeo”(“onnong 17” was selected through line selection and regional yield trials. In particular, the new variety revealed at the earlier mid of August compared to that of “aengdongchalbyeo” the early of September, and it was considerably tolerant to a field lodging due to its shortened culm length. Also, “ogwonchalbyeo”had a higher ripened grain ratio and 1,000 grain weight compared to the original variety. The brown grain yield of the new variety was about 5.40 MT/ha, which was 11.3% higher than that of the original variety, in the regional yield trials at 3 different fields during 2000∼2001. The brown and milled grains of the new rice variety contained 20 to 65% higher amount of total amino acids, respectively than that of the original and two checks. For chlorophyll -a, -b and total chlorophyll, the new variety showed nearly two-fold higher than the checks, and for the carotenoid, it had 5.3 –7.6 times higher amount. These results showed that the new variety can be cultivated as a special green-kerneled glutinous rice with high functional compounds.