A comparative phenotypic study between bl2 and spl6 mutant wasperformed to characterize spot formation mechanisms of bl2 mutant. Small spots appeared at the seedling stage in bl2 and later it covered large round areas on the leaves whereas, relatively small red spots in parallel line on both leaf surfaces at late tillering stage were observed in spl6. Vegetative and reproductive growth was reduced due to lesion formation at early age in the mutants. Lower growth habit and agronomic trait value was observed in mutants as compared to wild type plants. Genetic segregation data among F2 population revealed that both mutants are recessive in nature. Mesophyll chloroplast was not found in spotted area which demonstrates the damage of chloroplast cell at spotted area due to cell death. Transmission electron microscopy also confirmed the chloroplast damage. Increased level of total chlorophyll and hydrogen peroxide content were observed till 45 days of growth after transplantation under natural environment and dropped at 60 days. Catalase activity was increased until 45 days and decreased at 60 days whereas very slight level difference in protein content was observed. However, increasing level of total ascorbic acid contents were found in spl6 and bl2 as compared with wild type till 60 days after transplantation. Higher expressions of OsPDI and OsGPX1 in bl2 spotted leaves were found whereas OsTPX expression was very low in the spotted leaf. (This research was supported by the National Research foundation of Korea, Grant 0070065).

Rice with purple colored pericarp deposit anthocyanin on the seed coat and color accumulation increased rapidly during seed development. The purple color of rice pericarp is genetically determined by the Prp locus. Inheritance of purple pericarp was studied in Prp/ Kumgangbyeo (indica type Korean variety). Pericarp color of the F1 plants was purple and the F2 population of 274 plants segregated into 3 purple: 1 white ratio indicating dominant nature of the purple color. Comparative proteomic approaches using 2-DE were applied to analyze the protein profiles and molecular mechanism of purple color formation in ricepericarp. Results revealed that approximately 1,500protein spots were reproducibly detected in the gels with silver staining across the two biological replicates. Among them, 46 proteins were expressed differentially between purple color pericarp rice and white color pericarp of the wild type rice, in which 28 and 16 protein spots were more than two fold up regulated in the wild type and purple pericarp, respectively. MALDI-TOF MS analysis of nine spots revealed that putative fructokinase,embryo-specific protein and one unknown proteins were abundant in the wild type, whereas, anthocyanidin synthase, putative chloroplast inner envelope protein, and dihydroflavonol reductase were highly abundant in the Prp rice. Results indicated anthocyanidin synthase and/or dihydroflavonol reductase might be involved in the biosynthetic pathway of the purple color formation in the rice pericarp. [This research was supported by the Grant funded by Agricultural R&D Promotion Center, ARPC (IPET project number: 108091-05-1-CG000)].