Seong-Hwan Oh

Comparative analysis of physicochemicals and antioxidative properties of new giant embryo mutant, YR23517Acp79, in rice (Oryza sativa L.)

Nutritional and physicochemical properties of new giant embryo mutant rice (YR23517Acp79, YR) were analyzed. YR exhibited increased total protein (9.3±0.3%), lipid (3.7±1.1%), amino acid (663.28±1.9 mg/g), and mineral contents (Ca=284.0±6.2, Mg=1417.5±13.6 mg/kg). In YR brown rice four major physicochemicals, including gamma-aminobutyric acid (brown rice= 0.46±0.014 mg/g), γ-oryzanol (0.43±0.021 mg/g), vitamin B1 (6.42±0.3 mg/kg), and tocopherols (alpha= 2.68±0.1, beta=0.11±0.01, gamma=0.05±0.001 mg/100 g) increased in comparison to reported giant embryo (Keunnunbyeo, KB) and normal embryo rice (Ilmibyeo, IB). YR showed higher scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (0.2 g/mL=57.1±2.25) and 2,2′-Azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (0.2 g/mL=50.2±1.45) radicals but also inhibited lipopolysaccharide-induced nitric oxide production without cytotoxicity. These results indicate YR is a high quality functional rice due to its high nutrition content and antioxidant effects of physicochemicals.

A Waxy Black Giant Embryo Earley Maturing Rice Variety ‘Nunkeunheugchal’

Nunkeunheugchal (registration No. 01-0001-2014-4), a black waxy giant embryo rice cultivar, was developed by the rice breeding team of National Institute of Crop Science (NICS), RDA in 2012. This cultivar was derived from the cross between ge and Josaengheugchal in 2004/2005 winter season, and selected by a promising line, YR25277-B-B-314-2, was selected and designated as the line of Milyang263 in 2009. The local adaptability test of Milyang263 was carried out at four locations from 2010 to 2012 and it was named as Nunkeunheugchal. This variety is a early maturity cultivar. It has 65 cm in culm length and 72 spikelets per panicle, and 1,000 grain-weight of brown rice is 17.8 g which is less than that of Josaengheugchal. This variety is resistant to leaf blast, but susceptible to bacterial blight, neck blast, virus disease and insect pest. The yield potential of Nunkeunheugchal was about 3.54 MT/ha as brown rice at ordinary fertilizer level in local adaptability test for three years. Nunkeunheugchal possesses benefits to rice consumers because of high amounts of GABA, anthocyanin, calcium and iron. This variety would be adaptable to the paddy field of middle and southern plain region of Korea.

Differential Tolerance of Rice Cultivars to Mesotrione-Contained Herbicides

Greenhouse experiment was conducted to evaluate tolerance of six rice cultivars, three IndicaJaponica rice (long grain, cv. Dasanbyeo, Segejinmi and Hanareumbyeo) and three Japonica rice (short grain, Nampyung, Ilpumbyeo and Junamjosaeng) cultivars, to mesotrione+pretilachlor (MP) and bensulfuron-methyl+mesotrione+pretilachlor+pyriftalid (BMPP) in transplanting rice. Two herbicides were applied at 90 g and 180 g a.i. to three to four leaf stage rice at 5 and 15 days after transplanting, respectively. Related study was also conducted to compare for IndicaJaponica and Japonica rice cultivars at different MP rates. Response to two herbicides varied with respect to rice cultivars and herbicide rates. All IndicaJaponica rice cultivars exhibited susceptible to both MP and BMPP as reflected by increased visual injury, shorter plant height and higher plant dry matter reduction when compared with nontreated rice cutlivars. The degree of foliar chlorosis by MP at 90 g a.i. was 5~6 at 7 days after treatment(DAT) but it was decreased to 3~6 at 14DAT. The degree of leaf chlorosis treated with 180 g a.i. MP was 6~7 at 7DAT and it was also decreased to 3~8 at 14 DAT. The plant hight of IndicaJaponica rices was inhibited by 18~43% at application of 90 g a.i. MP and 30~50% at 180 g a.i. MP. The dry matter reduction was greater than that of plant height inhibition, showing 46~73% at 90 g a.i. MP and 65~82% at 180 g a.i. MP. Similar leaf chlorosis injury and growth inhibition of rice cultivars was observed in the BMPP treatment. The injury and growth inhibition by MP and BMPP increased with increase in herbicide rate from 90 g a.i. to 180 g a.i. . However, most of the Japonica cultivars are tolerant to MP and BMPP at both rates. There was no visible leaf chlorosis but plant height and dry matter production were slightly reduced at 180 g a.i. . Based on value determined in reduction of shoot dry weight for MP, the IndicaJaponica rice showed 12.9 fold lower compared with the Japonica rice. The result indicates that rice cultivars vary in tolerance to herbicides of MP and BMPP and IndicaJaponica rices were more susceptible than the Japonica rices to the MP and BMPP.

Comparative studies on major nutritional components of black waxy rice with giant embryos and its rice bran

The concentration of nutrients in brown rice is mainly associated with embryo size. Various beneficial components have been purified from rice bran. Recently developed black waxy rice with a giant embryo (‘Milyang 263’, BGE), which is the get mutant of the GE gene, was selected and analyzed to produce high quality nutritional components. γ-Aminobutyric acid (GABA) content in BGE rice bran, one of the most important nutritional compounds in rice, showed a 10.6-fold increase (2.66±0.48 mg/g) compared to that of BGE brown rice (0.25±0.01 mg/g). In addition, brown rice and BGE rice bran showed enriched amylopectin (94.5±0.5 and 97.0±0.0%) and bioactive anthocyanin [Cy-3-G: 75.15±4.18 (brown rice), 82.97±0.81 (rice bran) and Pn-3-G: 1.52±0.50 (brown rice), 4.33±0.20 (rice bran); mg/100 g] contents. These results suggest that BGE rice bran can be used as an excellent raw material to efficiently produce high quality essential amino acids, cyanidin-3 glycoside-enriched anthocyanins, and GABA.

Anti-pigmentation effect of serotonin alkaloid isolated from Korean barnyard millet ( Echinochola utilis )

Investigation of the melanogenesis inhibitory effect of barnyard millet grain extracts (BME) led to isolation of compounds against mushroom tyrosinase and B16 melanoma cells. Chromatography yielded five phenolic compounds, among which n-p-coumaroyl serotonin (1, CS) exhibited potent non-competitive inhibition (IC50 =8.8 μM) compared with that of kojic acid (IC50=14.6 μM) against mushroom tyrosinase. More importantly, CS decreased melanin content to eight times lower (IC50 =11.6 μM) in B16 melanocytes than that of feruloyl serotonin (2, FS, IC50 =86.5 μM) without cytotoxicity. CS significantly inhibited the protein expression of tyrosinase, tyrosinase-related protein-1 (TRP-1), TRP-2, and microphthalmia-associated transcription factor using immunoblotting. Furthermore, molecular docking simulations were also carried out to investigate the structure related to the inhibitory activities. Therefore, BME can be used as a natural source of depigmentation to prevent melanogenesis.

Studies of Physicochemical Properties of Baby Powder Developed from Rice-flour

Baby powder is an astringent powder used to prevent diaper rash. It also has other cosmetic uses. In general, it is composed of talc powder (talcum powder). Talc powder is harmful if inhaled because it can cause significant lung damage. With the aim of developing a new rice-based baby powder, three kinds of rice varieties were selected and pulverized. To determine the cost-effectiveness of the different states of rice powder, several milling processes were tried, and the powder characteristics of the resulting rice powder, such as particle size, biological activities, digitalized color value, and moisture content before and after coating treatment with essential oil and silicon oil, were examined. “Goami” showed good flour characteristics with respect to lightness (92.0, L*[D65] value) and particle size (8.9 μm). SEM analysis showed that the rice powder particles coated in the essential oil and silicon oil showed a smoother and rounder appearance than those of the talc powder. In addition, the average particle size was decreased by the essential oil and silicon oil coating. The silicon oil coating solved the problem of moisture absorption in rice flour. Rice flour properly coated with essential oil and silicon oil shows great potential as a new material source of powder.

Application of SSR Markers and Real-time PCR for Variety Identification in Azuki-bean (Vigna angularis (Willd.) Ohwi and Ohashi)

The azuki bean in Korea consists of seven domestic varieties which have been developed and registered for the public during last 25 years. Here, we present a simple but reliable method to screen and identify Korean azuki bean varieties. A method based on simple sequence repeat (SSR) markers is widely used for prominent gene identification and variety discrimination. In molecular biology, real-time polymerase chain reaction (PCR) is a laboratory technique based on the polymerase chain reaction that is used to amplify and simultaneously quantify a targeted DNA molecule. It enables easy detection of a specific sequence in a DNA sample without performing electrophoresis and further processes. For separation of seven Korean azuki bean varieties, 110 unique azuki bean SSR markers from an (AG)n-enriched library were selected, synthesized and used for polymerase chain reaction (PCR). Data were taken through acrylamide gel electrophoresis and automated multi-capillary electrophoresis system for selection of specific markers and then changed into proper formats for data mining analysis. Ten primer pairs that showed high polymorphism were chosen for the indepth study. These ten primers were re-amplified with real-time PCR and checked the cycle threshold (Ct) and temperature (Tm) for comparison of amplification sequence in seven varieties. Consequently, a total of 20 alleles and 6 SSR primers were detected from the standard PCR amplification. Within these 6 primers, 7 alleles of 3 SSR primers were isolated for variety identification. From real-time PCR results, 3 SSR primers were selected as efficient markers for discrimination of seven Korean azuki bean varieties. The approach described here could be applied in monitoring our varieties and can be adapted in the azuki bean breeding program.