Compared to wide ranges of genetic variation of natural populations, very limited Miscanthus cultivar has been released. This study was the first report on the development of Miscanthus cultivar by means of radiation breeding. Seeds of M. sinensis were initially exposed to gamma rays of 250 Gy for 24 h, generated from a 60Co gamma-irradiator. The irradiated seeds were sown and then the highly tiller-producing mutants were selected for this study. Biomass-related parameters including tiller number, plant height, stem diameter, and leaf number were measured. Ploidy level and internal transcribed spacer (ITS) were investigated to characterize the mutants compared to wild type (WT) Miscanthus. Plant height and tiller number were negatively related, where multi-tillering mutants were relatively short after 4 month growth. However stem diameter and leaf number were greater in mutants. All the materials used in this study were diploid, implying that the mutants with greater tiller numbers and stem diameter were not likely related to polyploidization. Based on the sequence of ITS regions, the mutants demonstrated base changes from the gamma irradiation where G+C content (%) was decreased in the ITS1, but increased in ITS2 when compared to WT sequence. ITS2 region was more variable than in ITS1 in the mutants, which collectively allows identification of the mutants from WT. Those mutants having enhanced tillers and allelic variations might be used as breeding materials for enhanced biomass-producing Miscanthus cultivars.

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.

The protein in soybean seeds accounts for approximately 40% of the dry seed weight. Two major storage proteins, 7S and 11S, constitute 70-80% of the total storage proteins in the seeds. In this study, the variation of total soluble protein extracts from 1152 soybean landraces that have been collected from South Korea were studied using high-throughput screening method with HT Protein Express Labchip (Caliper Life Sciences, Inc.). Seven distinct protein band patterns - four protein sub-units of 11S and three sub-units of 7S, were taken into account and their presence or absence were analyzed. Among the 1152 landraces, 525 genotypes were identified as lacking lipoxygenase, 255 lacking α1 subunit, 680 lacking α subunit, 169 lacking β subunit, 140 lacking acidic, 114 lacking Kunitz Trypsin Inhibitor (KTi) and 199 lacking basic protein patterns. The high-throughput protein analysis is helpful in screening a large number of populations with less time and minimum labor. The selected genotypes with low amounts or lacking of anti-nutritional factors such as trypsin inhibitor, lipoxygenase and α subunit would be used for future breeding purpose of quality improvement in soybean protein.

Purple acid phosphatase is important for phosphorus remobilization in plants, but its role in plant adaptation to low phosphorus availability is not known. The cDNA encoding O. sativa purple acid phosphatase (OsPAP1) has 1008 bp with an open reading frame of 335 amino acid residues. The amino acid sequence of OsPAP1 cDNA shows of 50-51% identity with other plant purple acid phosphatases. OsPAP1 was expressed in rice plants and in cell cultures in the absence of phosphate (Pi). The expression was organ-specific with the strongest expression in Pi-deprived roots. Functional expression of the OsPAP1 gene in the transgenic Arabidopsis line was confirmed by northern and western blot analysis. OsPAP1 overexpression lines had higher phosphatase activity than wild-type. Overexpression of OsPAP1 in Arabidopsis plants resulted in increased Pi accumulation under Pi sufficient condition. These results show that the OsPAP1 gene represents more efficient Pi uptake and can be used to develop new transgenic dicotyledonous plants.