Im-Soo Choi

Expression of BrD1, a plant defensin from Brassica rapa, confers resistance against brown planthopper (Nilaparvata lugens) in transgenic rices.

Plant defensins are small (5-10 kDa) basic peptides thought to be an important component of the defense pathway against fungal and/or bacterial pathogens. To understand the role of plant defensins in protecting plants against the brown planthopper, a type of insect herbivore, we isolated the Brassica rapa Defensin 1 (BrD1) gene and introduced it into rice (Oryza sativa L.) to produce stable transgenic plants. The BrD1 protein is homologous to other plant defensins and contains both an N-terminal endoplasmic reticulum signal sequence and a defensin domain, which are highly conserved in all plant defensins. Based on a phylogenetic analysis of the defensin domain of various plant defensins, we established that BrD1 belongs to a distinct subgroup of plant defensins. Relative to the wild type, transgenic rices expressing BrD1 exhibit strong resistance to brown planthopper nymphs and female adults. These results suggest that BrD1 exhibits insecticidal activity, and might be useful for developing cereal crop plants resistant to sap-sucking insects, such as the brown planthopper.

Black rice bran as an ingredient in noodles: chemical and functional evaluation.

This study examined the feasibility of using black rice bran (BRB) as an ingredient of noodles and evaluated the effect of BRB incorporation in noodles in terms of chemical and functional attributes. Noodles were prepared with BRB as an ingredient at different levels (2%, 5%, 10%, and 15%). Addition of BRB (5%, 10%, and 15%) significantly decreased the cohesiveness of noodles in texture evaluation. Noodles with different levels of BRB were functionally evaluated and content of polyphenolics, flavonoids, and anthocyanins were improved compared to the control. Additionally, antioxidant activity of BRB noodles was increased compared to the control. BRB can be an excellent ingredient to increase the nutritional value and antioxidant properties of noodles.

Identification of Quantitative Trait Loci Associated with Rice Eating Quality Traits Using a Population of Recombinant Inbred Lines Derived from a Cross between Two Temperate japonica Cultivars

Improved eating quality is a major breeding target in japonica rice due to market demand. In this study, we performed genetic analysis to identify quantitative trait loci (QTLs) that control rice eating quality traits using 192 recombinant inbred lines (RILs) derived from a cross between two japonica cultivars, ‘Suweon365’ and ‘Chucheongbyeo’. We evaluated the stickiness (ST) and overall evaluation (OE) of cooked rice using a sensory test, the glossiness of cooked rice (GCR) using a Toyo-taste meter, and measured the amylose content (AC), protein content (PC), alkali digestion value (ADV), and days to heading (DH) of the RILs in the years 2006 and 2007. Our analysis revealed 21 QTLs on chromosomes 1, 4, 6, 7, 8, and 11. QTLs on chromosomes 6, 7, and 8 were detected for three traits related to eating quality in both years. QTLs for ST and OE were identified by a sensory test in the same region of the QTLs for AC, PC, ADV, GCR and DH on chromosome 8. QTL effects on the GCR were verified using QTL-NILs (near-isogenic lines) of BC3F4–6 in the Suweon365 background, a low eating quality variety, and some BC1F3 lines. Chucheongbyeo alleles at QTLs on chromosomes 7 and 8 increased the GCR in the NILs and backcrossed lines. The QTLs identified by our analysis will be applicable to future marker-assisted selection (MAS) strategies for improving the eating quality of japonica rice.

Changes in Quality Properties of Brown Rice after Germination

The objective of this study was to evaluate quality properties, including amylose, alkali digestion value (ADV), and amylogram, of brown rice and germinated brown rice of some cultivars in Korea for rice processing products. The protein content of brown rice was significantly higher than those of germinated brown rice. The amylose content of the samples ranged from 17.09 to 18.85%. Alkali digestion value (ADV) of brown rice and germinated brown rice were described as a grade of 2-5 and 4-7, respectively. In a rapid visco analyzer (RVA) examination, pasting temperature of brown rice and germinated brown rice was 67.93-68.05℃. In addition, the pasting characteristics of brown rice were significantly higher than those of germinated brown rice. A texture analysis test showed that germinated brown rice Haiami had the lowest hardness and germinated brown rice Samkwang had the highest adhesiveness.

SSR Analysis of Genetic Diversity and Cold Tolerance in Temperate Rice Germplasm

A total of 23 elite rice cultivars from eight countries were evaluated for cold tolerance using two screening methods at Chuncheon Substation, National Institute of Crop Science (NICS), Republic of Korea. The rice cultivars Jinbu, Mustaqillik, and Avangard showed cold tolerance and high spikelet fertility (63-79%) in cold-water irrigation screening. Under greenhouse screening, five cultivars (Giza 177, Avangard, Mustaqillik, Jinbu, and Jungan) showed high cold tolerance and high spikelet fertility (71-81%). Simple sequence repeat (SSR) marker analysis of 21 genotypes revealed two major clusters, the japonica and indica groups, with a genetic similarity of 0.69. Out of 21 rice cultivars, only four (Giza 178 from Egypt, Attey and Zakha from Bhutan, and Millin from Australia) fell under the indica cluster. The cold-tolerant varieties Jinbu, Mustaqillik, and Avangard were clustered with the japonica group, which had genetic similarity of 0.83. These varieties are considered as potential germplasm that will help diversify the japonica gene pool for cold-tolerant rice breeding. A one-way linear analysis of variance identified a significant relationship between individual alleles and traits. Three SSR markers were significantly associated with spikelet fertility under cold-water irrigation on chromosomes 1, 2, and 7. Five SSR markers were associated with spikelet fertility under a cool-environment greenhouse on chromosomes 8, 9, 10, and 12. The SSR markers associated with cold tolerance may also be useful as selection markers in indica/japonica cross combinations to improve cold tolerance.

Resistance Genes and Their Effects to Blast in Korean Rice Varieties (Oryza sativa L.)

A total of 98 varieties consisting of 88 japonica and 10 Tongil-type of rice were analyzed to resistant genes and their effects to blast. The 13 major blast resistance (R) genes against Magnaporthe oryzae were screened in a number of Korean rice varieties using molecular markers. Twenty-eight (28.6%) were found to contain the Pia gene originating from Japanese japonica rice genotypes. The Pib gene from BL1 and BL7 was incorporated into 39 Korean japonica varieties, whereas this same gene from the IRRI-bred indica varieties was detected in all Tongil-type variety. The Pii gene was found in 17 of the japonica varieties. The Pii gene in Korean rice varieties originates from the Korean japonica variety Nongbaeg, and Japanese japonica varieties Hitomebore, Inabawase, and Todorokiwase. The Pi5 gene, which clusters with Pii on chromosome 9, was identified only in an Tongil-type, Taebaeg. Thirty-four varieties were found to contain alleles of the resistance gene Pita or Pia-2. The Pita gene in japonica varieties was inherited from the Japanese japonica genotype Shimokita, and the Pita-2 gene was from Fuji280 and Sadominori. Seventeen japonica and one Tongil-type varieties contained the Piz gene, which in the japonica varieties originates from Fukuhikari and 54BC-68. The Piz-t gene contained in three Tongil-type varieties was derived from IRRI-bred indica rice varieties. The Pi9(t) gene locus that is present in Korean japonica and Tongil-type varieties was not inherited from the original Pi9 gene from wild rice Oryza minuta. The Pik-multiple allele genes Pik, Pik-m, and Pik-p were identified in 24 of the varieties tested. The Pit gene inherited from the indica rice K59 was not found in any of the Korean rice varieties tested. In haplotype analysis for the loci related to two QTLs as well as five major resistant genes and, two

A high biomass yield and whole crop silage rice cultivar 'Mogyang'.

R

Lodging and Pre-harvest Sprouting Tolerant, High Quality and Suitable for Processing Cooked Rice ‘Jungmo1017’

genes Piz and Pita showed stable resistant effects to blast nurseries and isolates in~Korea.

The Change in Biological Activities of Brown Rice and Germinated Brown Rice

‘Mogyang’, a new high biomass yield and whole crop silage rice (Oryza sativa L.) cultivar, is developed by the rice breeding team of National Institute of Crop Science, R.D.A., Suwon, Korea, during the period from was to 2010 and released in 2011. It was derived from a cross between SR24592-HB2319/IR73165-B-6-1-1. This cultivar has about 118 days of growth duration from seeding to heading and has long and erect leaves (culm length 93 cm). It has tough thick culm with strong lodging tolerance. This cultivar has a few less tillers per hill and markedly more spikelet numbers per panicle. ‘Mogyang’ has wide and stay green leaf compared other whole crop silage varieties. This new variety has grain shattering resistance and disease resistance for blast and dwarf virus. This variety has good qualities for whole crop silage with high TDN (Total Digestive Nutrient) yield and low NDF (Neutral Detergent Fiber) and low ADF (Acid Detergent Fiber) compared to common high grain yield varieties. The biomass and TDN yield performance of ‘Mogyang’ was 59.5% (chemical properties), 17.7 MT/ha (biomass yield), individually in local adaptability test for three years. ‘Mogyang’ is adaptable to central plain area, southern plain area of Korea.

Comparison of Antioxidant Activities by Different Extraction Temperatures of Some Commercially Available Cultivars of Rice Bran in Korea

The ‘Jungmo1017’ is a japonica rice variety developed from a cross between Suweon462 which has a good plant architecture, cold tolerance, moderately tolerant to leaf blast and bacterial blight and medium maturing habit, and Yeongdeog34 which has translucent milled rice and good milling properties, by the rice breeding team at NICS, RDA in 2011. The heading date of ‘Jungmo1017’ is August 16 and it is six days later than ‘Hwaseong’. ‘Jungmo1017’ has 65 cm of culm length which is 18 cm shorter than those of ‘Hwaseong’ and 93 spikelet per panicle. The pre-harvest sprouting rate of ‘Jungmo1017’ is 8.6% that is lower than 27.7% of ‘Hwaseong’ on local adaptability test (LAT). It showed resistance to blast diseases and moderately resistant to bacterial blight (K1 race) and stripe virus, but susceptible to other races (K2, K3 and K3a) of bacterial blight, viruses and planthoppers. The milled rice of this variety exhibits translucent, clear non-glutinous endosperm and medium short grain shape. It has better palatability index of cooked rice (0.53) than that of ‘Hwaseong’. ‘Jungmo1017’ showed lower protein content (6.4%) and amylose content (18.0%). ‘Jungmo1017’ could use aseptic-packaged cooked rice or processing cooked rice because its hardness of cooked rice is soft, setback and balance is low and palatability of cold and aseptic rice showed high score. The characters related to milling is better than those of ‘Hwaseong’. ‘Jungmo1017’ showed 5.01 MT/ha of milled rice productivity at 7 sites of middle plain, southern mid-mountainous and south-east coastal area in ordinary cultivation. ‘Jungmo1017’ could be adaptable to the middle plain area in Korea.