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.

In plant, senescence is associated with various aspects of the final stage of leaf development, nutrient relocation from leaves to reproducing seeds and stress resistance, and yield which is the most important trait in crops. Thus, the increase of knowledge on the regulatory processes of plant senescence will allow us to manipulate senescence for agronomic benefit in the future. of genetic studies have been conducted with mutants, where most of studies were focused on the delayed senescence mutants which are associated with positive factors on senescence by treating EMS to Koshikari, we induced a mutant showing early senescence phenotype, which possibly enable us to identify a negative factor of senescence. The appearance of the mutant is identical before booting stage and then the mutant showed senescence phenotype rignt before booting stage whereas Koshikari have health green leaves. The clumn length of the mutant is 98cm and the panicle length is 23cm as same as those of Koshikari. The chlorophyl contents of the mutant leaves, measured by SPAD, decreased during senescence. The soluble protein contents in the mutant leaves also decreased but no differences in the constitution reolved 1D-SDS-PAGE was detected. However, an additional shotgun proteomic approach to detect the differences of the protein constitutions during the senescence in the mutant leaves will be conducted.