본 리뷰의 목적은 벼 종자 저장단백질 구조분석 및 발현특성분석 결과 종합화를 통하여 종자형질 개선 등의 실용화연구를 위한 기반구축을 모색하는데 있다. 최근 벼 염색체염기서열완전해독 연구 결과를 이용한 유용형질 유전자 분리 및 실용화 연구가 많이 진행되고 있다. 특히 벼 종자 저장단백질은 인류에게는 주요 영양원으로 사용되어지며 종자 발아시에는 식물체 성장을 위한 질소원으로 사용되어진다. 벼 종자 저장단백질의 분류는 용매에서의 용해도에 따라 약산성 및 알카리 용해성의 glutelin, 알코올 용해성의 prolamin, 염 용해성의 globulin으로 나눈다. 벼 염색체 상에는 11개의 glutelin 유전자와 33개의 prolamin 유전자가 존재하며 prolamin 유전자의 경우 5번 염색체 15 Mb 부위에 15개의 유전자가 위치하였다. 이와 같이 종자저장단백질 유전자들이 동일 염색체 부위에 위치하고 있는 것은 진화학적으로 동일 염색체에서 유래하였거나 유사한 유전자발현 조절영역을 가지고 있음을 의미한다. Globulin 유전자는 5번 염색체에 단일 유전자로 존재하였다. 마이크로어레이를 이용한 종자저장 단백질 관련 유전자의 조직 특이 발현 양상을 분석한 결과 glutelin과 대다수의 prolamin 합성 유전자는 종자배유에서만 발현을 하였으며 소수의 prolamin과 globulin 합성 유전자는 종자배유와 발아종자에서도 발현을 나타내었다. 종자 저장단백질의 프로모터부위를 분리한 후 종자에서의 발현 양상을 분석한 결과 glutelin type C1 프로모터가 종자의 전체 부위에서 발현을 나타내었으며 glutelin type B5와 α-globulin 프로모터가 많은 양의 발현을 나타내었다. 본 리뷰를 통하여 벼 종자 저장단백질의 구조및 발현특성 연구 진행사항을 살펴보았다. 이러한 연구 동향분석은 종자형질 개선 및 물질생산 등의 실용화 연구를 수행하는 연구자들에게 최근의 연구 현황을 제공할 수 있을 것으로 생각된다.

본 연구는 전이인자 Ac/Ds를 이용하여 세계적인 경쟁력을 갖춘 삽입변이 집단을 구축하고 Ds 삽입에 대한 분자학적 정보를 획득하여 database 화에 이용하는 것을 목적으로 하였다. 또한 농업적 유용유전자들의 생물학적 기능을 구명하고 생명공학적 방법을 통하여 새로운 작물 창출에 활용하고자 한다. 본연구를 통하여 얻을 수 있는 자료와 정보는 벼의 유전자 기능분석을 보다 효율적으로 실시하고 유용 유전자를 선발하여 육종에 이용함과 아울러 또한 이들의 지적 소유권 획득에 기초자료로 이용될 수 있을 것이다. 1. T1 진전에 의한 대량 고정종자 생산 확보를 위해 Largescale screening 활용하고 발아 활력 유지를 위해 종자를 장기보존하였다. 그 결과 Ds Knockout 육종소재의 안정적 재료공급 체계 확립하였는데 종자 증식용 파종상의 규격화를 통한대량 증식 방법 확립였고 증식계통의 목적에 맞는 재배 방법채택을 통한 편의성을 증진하였다. 2. 변이체의 선발은 각 생육 시기별 변이체 특성검정 및 선발하였으며 2008년도에는 변이율이 5.15%를 보였으나 2009년에는 4.34%로 낮았으며 평균 4.75%의 변이율을 나타냈다. 2010년 증식계통은 생육이 불량하여 표현형 조사는 불가하여 바로 이앙하여 증식하였다. 특히 spotted leaf(spl)의 형태를 나타내는 변이형이 우점하였다. 유묘기의 Ds 증식 집단에서의 표현형 변이는 주로 엽록소 이상을 보이는 변이체가 많이 관찰되었다. 3. 흑미 삽입변이체의 종자특이 전사인자의 발현 분석을 수행하기 위하여 컴퓨터 분석법을 이용하여 흑미 종자의 안토시아닌 생합성 발현 유전자를 동정하고 안토시아닌 생합성 유전자의 발현 분석을 통한 합성 기작 연구를 수행하였다. 그 결과 흑미 종자 삽입변이체 선발하였는데 115,000점의 Ac/Ds 삽입변이체 중 흑미 9계통을 선발하였다. 4. 흑미 종자의 유전자 발현 분석을 연구하기 위하여 Microarray 통계분석을 실시하였는데 672개의 안토시아닌 생합성 관련 유전자 중 전이인자 hyper-geometric 통계 분석으로 12개 전이인자 분류별 82개의 생합성 관련 전이인자 유전자 선발하였다. 5. 최근 기능유전체 연구의 효율을 높이기 위하여 변이체에대한 총체적인 해석과 함께 변이체의 표현형 변이와 삽입염기서열 분석의 연관성을 데이터 베이스화하는 이른바 Phenome 데이터베이스로 가는 추세이다. 이러한 Phenome 분석에 삽입변이집단의 데이터베이스가 활용될 것으로 기대된다.

본 연구의 목적은 일본의 식물유전체 연구 동향분석을 통하여 농업생산성 향상을 위한 연구방향을 모색하는데 있다. 일본에서의 식물유전체 연구는 국가연구소 주도적으로 이루어지고 있으며 벼 등 다양한 구조유전체연구결과를 이용한 유용형질 유전자 기능분석 및 실용화 연구에 집중하고 있다. 식물 구조유전체 및 기능유전체 연구를 위한 기반조성으로 농업생물자원연구소(National Institute of Agrobiological Sciences, NIAS)에서는 벼과 식물의 유전체 DB 구축, 이화학연구소(Rikagaku Kenkyusho, RIKEN)에서는 애기장대 유전체 DB 및 식물 완전장 유전자 DB 구축, 국립유전학연구소(National Institute of Genetics, NIG)에서는 국가생물자원프로젝트(National Bio Resource Project) DB를 구축하여 관련 연구자들에게 다양한 식물 유전체 정보 및 연구재료들을 제공하고 있다. 최근 세계적 식량환경 문제해결 및 혁신적 농업기술개발을 목표로 신농업전개 게놈프로젝트(New Agri-genome Project)를 수행하여 수량, 내병성, 환경문제 해결을 위한 유용 유전자분리, 이용 등 세계적인 연구 성과를 도출하고 있다. 또한 개도국의 농업생산성 향상을 위하여 JIRCAS 에서는 식물유전체 연구 기술지원을 하고 있으며 아프리카 토양에 적합한 다수성의 NERICA 벼를 개발하여 식량생산 증진에 기여하고 있다. 본 연구를 통하여 우리에게 정보가 부족하였던 일본의 식물유전체 연구 진행사항을 살펴보았다. 이러한 연구동향 분석은 동식물 유전체 연구를 수행하는 연구자들에게 최근의 유전체 기술정보 등을 제공 할 수 있으며 세계적인 식량, 에너지, 환경문제의 해결에 크게 기여 할 것으로 생각한다.

The rice recombinant inbred lines derived from Milyang23 and Gihobyeo cross were used in genetic mapping and QTL analysis studies. In this study, we developed a new 101 CAPS markers based on the SNPs in the whole genome region between these varieties. As a result, the total genetic distance and average distances were 1,696.97 cM and 3.64 cM, respectively. In comparison to the distance of the previous genetic map constructed based on 365 DNA markers, the new genetic map was found to have a decreased distance. The map was applied for the detection of QTLs on all seven traits relevant to diameter of stem internode, length of culms, length of panicles and the number of panicles including the correlation analysis between each trait. The QTLs results were similar to the report in previous studies, whereas the distance between the markers was narrowed and accuracy increased with the addition of 101 CAPS markers. A total of 9 new QTLs were detected for stem internode traits. Among them, qI1D-6 had higher LOD of 5.1 and phenotype variation of 50.92%. In this experiment, a molecular map was constructed with CAPS markers using next generation sequencing showing high accuracy for markers and QTLs. In the future, developing more accurate QTL information on stem internode diameters with various agriculturally important traits will be possible for further rice breeding.

Perilla is a annual herb plant of the mint family, Laminaceae and mainly cultivated in eastern Asia, i.e. Korea, China and Japan. In response to an increased interest for healthy supplement food from the public, people are focusing on the properties of perilla. The applicable parts of perilla plants are the leaves and seeds. Perilla has been cultivated as a source of unsaturated fatty acid oil. But in spite of advantage of the important nutritional traits the genome or molecular studies on perilla remains largely unknown. Sequence comparisons of chloroplast (cp) genomes or nuclear ribosomal DNA (nrDNA) are of great important to provide a evidence for taxonomic studies or species identification or understanding mechanisms that underlie the evolution of perilla species. So, we tried to study a structural analysis of perilla genome and 45s nrDNA using 9 species (3 Diploid; Perilla B-17, P. hirtella, P. setoyensis / 6 Tetraploid; YCPL 285, YCPL 170, YCPL 205-1, YCPL 181-1, YCPL 177-1, YCPL 207-1). The complete cp genome and nrDNA of 9 perilla species were determined using Illumina sequencing technology and analyzed on the variance in base level between perilla B-17 and salvia miltiorrhiza. Total chloroplast genome size of perilla B-17 as a reference was 152,589 bp in length. We also identified an slightly overlapped intergenic regions between salvia miltiorrhiza and B-17. The results above will contribute to growing of molecular or genome structure and functional genomics of perilla available in studying perilla biology. For further study, we will look for genetic diversity of perilla species.

The next-generation sequencing(NGS) technology is being used for more effective genetic mapping. In previous study, we obtained 60x coverage of sequence from Milyang23 and Gihobyeo on average comparing with Nipponbare reference genome. Also, we developed new derived cleaved amplified polymorphic sequence(dCAPS) markers based on the single nucleotide polymorphisms(SNPs) in coding region sequence(CDS) between these varieties. Totally, 1,726,798 SNPs between Milyang23 and Gihobyeo were detected. Among them, 146 SNP were selected for making dCAPS markers and located on genetic map with previously reported 219 PCR-based DNA markers. The map was applied to the detection of quantitative trait loci(QTLs) for stem internode diameters, culm length and panicle length within MGRIL population, and six QTLs with relatively high LOD score were found at three chromosomes; culm length and stem diameter including the first internode diameter, third and fourth internode diameter. This study showed that the NGS allowed the rapid discovery of a large number of SNPs for dCAPS marker. So, we tried to find out more single nucleotide polymorphisms(SNPs) which were located on the whole genome sequence, such as un-translated region(UTR), intron, Inter-region and coding region sequence(CDS) between Milyang23 and Gihobyeo varieties. And we collected phenotypic information about culm length, panicle length, four stem internode diameters and panicle number in rice MGRIL population for QTLs. Furthermore, results of QTL analysis described above will shows relevance of molecular markers in mapping genes for useful breeding.

Low-molecular-weight glutenin subunits (LMW-GS) play a crucial role in the processing quality of wheat flour. They are encoded multi gene family located at the Glu-A3, Glu-B3 and Glu-D3 on the short arm of chromosome 1A, 1B and 1D respectively. Typical LMW-GSs are composed of three parts including a short N-terminal domain, a relatively short repetitive domain and a C-terminal domain. Further, typical LMW-GS sequences are divided into LMW-s, LMW-m and LMW-i types, on the basis of the first amino acid of the mature proteins (serine, methionine and isoleucine, respectively). Although it is known that the allelic variation of LMW-GSs affect the properties of dough, it is still not clear which LMW-GSs confer better bread-making quality because of the larger number of expressed subunits and their overlapping mobility with abundant gliadin proteins. Therefore, it is important to characterize LMW-GS genes and develop functional markers to identify different LMW-GS alleles for application in wheat breeding. In this review, we discuss the various aspects of LMW-GS, including their structural characteristics, the development of marker, relationship between LMW-GSs and bread wheat quality, and genetic engineering of the LMW-GSs.

We have generated 383 independent transgenic lines for genetically modified (GM) rice that contained GPD, UtrCSP, BrTSR15 and BrTSR53 genes overexpression constructs under the control of the constitutive CaMV 35S promoter. TaqMan copy number assay was determined inserted T-DNA copy number. Also FSTs analysis was isolated from 203 single copy T-DNA lines of transgenic plants and sequence mapped to the rice chromosomes. In analyzing single copy lines, we identified 95 FSTs, among which 37 (38.9%) were integrated into genic regions and 58 (61.1%) into intergenic regions. About 27 homozygous lines were obtained through multi-generations of planting, resistance screening and TaqMan copy number assay. To investigate the transgene expression patterns, quantitative real-time PCR analysis was performed using total RNAs from leaf tissue of single copy, intergenic region of T-DNA insertion and homozygous T2 plants. The mRNA expression levels of the examined transgenic rice were significantly increased in all of the transgenic plants. In addition, myc-tagged 35S::BrTSR15 and 35S::BrTSR53 transgenic plants were displayed higher levels of transgene protein than WT plants. These results may be useful for producing of large-scale transgenic plants or T-DNA inserted mutants in rice.

The next-generation sequencing (NGS) technology is being used for more effective genetic mapping and genome analysis. In this study, we performed whole-genome sequencing on the genomic DNA of Milyang23 and Gihobyeo using NGS and developed new cleaved amplified polymorphic sequence (CAPS) markers based on the single nucleotide polymorphisms (SNPs) in coding sequence between these varieties. Approximately, sequences of 60x coverage of the Nipponbare reference genome on average were obtained following Illumina sequencing. Totally, 1,726,798 SNPs between Milyang23 and Gihobyeo were detected. Among them, 149 SNP were selected for CAPS markers and located on genetic map with previously reported 219 PCR-based DNA markers. This map was applied to the detection of quantitative trait loci (QTLs) for stem internode diameters, culm length and panicle length in rice with MGRIL population. Newly 6 QTLs were detected for culm length (CL) and stem diameter (ID) traits including the first internode diameter (I1D), third internode diameter (I3D), and fourth internode diameter (I4D). Among those QTLs, qI1D5 and qCL5 had relatively higher LOD score and explained 8.99% and 4.24% of total variation. This study showed that the NGS allowed the rapid discovery of a large number of SNPs for CAPS marker. Only very small portion of SNPs through re-sequencing were used in this study. Furthermore, the results of QTL analysis described above shows relevance of molecular markers in mapping genes for useful traits.

It is well known that Dharial (Bangladesh origin and weedy rice line) has longer seed longevity than indica and japonica rice varieties. To study the genetic basis of seed longevity of Dharial, we developed 240 BC3F7 backcross recombinant inbred lines derived from the crosses between Dharial (a donor parent) and two korea rice accessions (recurrent parents) including Ilmi and Gopum, respectively. Among these lines, we selected two introgression lines with longer seed longevity and named them Ilmi-NIL and Gopum-NIL. Also, we developed an EMS-induced mutant line from Dharial which has shortened seed longevity, and named it Dharial-EMS. We performed re-sequencing of four rice accessions that are Dharial, Dharial-EMS, Ilmi-NIL, and Gopum-NIL. A total of 706×106 raw reads were generated which provided sequence data over 46x rice genome coverage per each accession. We did genome-wide variation analysis comparing produced re-sequencing data and the re-sequencing data of Ilmi from NABIC database with the Nipponbare reference sequence. By graphical analysis of SNP distribution in rice genome of the five accessions, we could select candidate chromosomal segments introgressed from Dharial in Ilmi-NIL and Gopum-NIL. The introgressed chromosomal segments were in seven regions in Ilmi-NIL and eight regions in Gopum-NIL, and four common introgressed regions between Ilmi-NIL and Gopum-NIL were identified. 2,758 SNPs between Dharial and Dharial-EMS were found in the introgressed regions. Also, we detected 450 genes including at least one SNP among these SNPs. This result will facilitate identification of genes and development of molecular markers for improvement of seed longevity.

Crops are exposed to various environmental stresses. These have been affecting the growth of crops, resulting in the severe loss of agronomic production in many countries. Therefore, development of new varieties of resistant crops is required to assure the desired productivity of crops in stress conditions. In this study, a putatively stress-related gene BrTSR53 was isolated from Brassica rapa. The BrTSR53 is 481 bp long and contains ORF region of 234 bp. The expression of BrTSR53 was determined by quantitative real-time PCR analysis. After 3 hr, the highest quantities of mRNA were revealed in cold and salt stress treatments. In drought stress treatments, there was the highest expression after 36 hr. Therefore, it was confirmed that the ORF in BrTSR53 should be a gene that confer increased resistance to B. rapa growing in different stress conditions. The ORF region of BrTSR53 gene was cloned into an expression vector, pYES-DEST52, and a new protein with molecular weight of 13 kDa was detected by western blot analysis. Also, stress tolerance tests showed that BrTSR53-ORF transgenic yeast exhibited increased resistance to the salt stresses compared with the control. In conclusion, the present data predicts that novel ORF in BrTSR53 can serve as an important genetic resource for abiotic stress resistance.

농작물은 다양한 외부 환경스트레스에 노출되어 있다. 환경스트레스는 작물의 성장에 영향을 주어 세계 각 지역의 농업 생산량을 심각하게 감소시키고 있다. 따라서 작물의 생산성을 높이기 위해서 다양한 환경스트레스에 내성이 강한 새로운 품종의 개발이 요구된다. 최근의 연구 동향은 환경스트레스 저항성 유전자를 작물에 도입시켜 환경 변화에 대한 저항성이 강한 작물을 개발하는 것이다. 본 연구에서는 배추의 저온, 고농도의 염과 건조 등의 환경스트레스에 대한 저항성 유전자로 추정되는 BrTSR53의 염기서열을 분석하였다. BrTSR53의 유전자의 총 길이는 481 bp이며 이중에서 ORF 부위는 234 bp이었다. 이 ORF의 염기서열 상동성을 분석한 결과 Arabidopsis에서 보고된 유전자와 유사한 것으로 나타났다. BrTSR53의 발현을 분석하기 위하여 quantitative real-time PCR을 실시하였다. 그 결과 배추를 고염 처리, 저온 처리하고 3시간 후에 가장 높은 mRNA 양을 보였으며, 건조 처리에서는 36시간 후에 발현량이 최대치를 보였다. 따라서 이 ORF는 환경스트레스에 대한 배추의 저항성 유전자임을 확인하였다. 그리고 BrTSR53 유전자를 효모발현 벡터인 pYES-DEST52에 삽입하고 western blot 분석법을 통해 효모에서 분자량이 약 13 kDa인 저항성 단백질의 발현을 확인하였다. 또한 BrTSR53 형질전환 효모는 염분 스트레스에 대한 저항성이 증가한 것으로 나타났다. 따라서 BrTSR53 유전자는 농작물의 환경스트레스 저항성을 높여줄 수 있는 주요한 유전자원으로 이용될 수 있다고 사료된다.

최근 급속하게 발달한 차세대 유전체분석기술을 기반으로 밀양23호와 기호벼의 유전체 서열을 분석하고, 새로운 CAPS 마커를 개발하였다. NGS를 통해 Nipponbare 유전체 길이의 60 배수만큼 염기서열을 결정하였고, CDS 안에서 두 품종간 특이적으로 나타나는 SNP를 CAPS 마커로 이용하였다. 새롭게 개발된 146개 CAPS 마커와 기존의 보고된 219개 마커를 통합하여 총 365개의 마커로 밀양23호/기호벼의 재조합자식 유전집단에 대해 분자 유전지도를 작성하였다. 벼의 줄기굵기와 간장 그리고 수장에 관한 QTL을 탐색한 결과, 총 19개의 유의성이 있는 QTL을 찾을 수 있었다. 이 중에 4개 줄기굵기 형질 관련 QTL과 2개 간장 형질 관련 QTL이 기존에 보고되지 않은 새로운 QTL이었다. 그 줄기굵기 QTL 중 가장 큰 LOD값을 갖는 qI1D5는 5번 염색체에서 탐색되었으며, 1절굵기 표현형 변이는 8.99%였다. 또한, 간장관련 QTL 중 가장 큰 LOD 값을 갖는 qCL5은 5번 염색체에서 탐색되었고, 이 QTL의 간장 표현형 변이는 4.24%였다. 재염기서열을 통해 밝혀진 SNP 중 소수만이 본 연구에 사용되었다. 향후 본 연구에서 밝혀진 SNP 정보를 이용한다면 더 많은 마커를 개발하여, 고밀도 유전지도 작성이 가능할 것이다. 더 나아가 MGRIL을 이용하여 농업적으로 유용한 형질에 대해 더 정확한 QTL 분석과 유용유전자의 개발이 가능하게 될 것이다.

Glutamine synthetase (GS) is an enzyme that plays an essential role in the metabolism of nitrogen by catalyzing the condensation of glutamate and ammonia to form glutamine. Exposure of plants to cadmium (Cd) has been reported to decrease GS activity in maize, pea, bean, and rice. To better understand the function of the GS gene under Cd stress in rice, we constructed a recombinant pART vector carrying the GS gene under the control of the CaMV 35S promoter and OCS terminator and transformed using Agrobacterium tumefaciens. We then investigated GS overexpressing rice lines at the physiological and molecular levels under Cd toxicity. The GS activity along with mRNA expression were found higher in transgenic than in wild type plants. And this is validated by the low malondialdehyde contents observed 10 days after treatment. GS overexpression in rice resulted in the modulation of expression of enzymes responsible for membrane peroxidation, which may result in the sudden death of plants. Our results thus describe the features of a transgenic rice plants with enhanced tolerance to Cd toxicity.

With the rapid development of sequencing technologies, next-generation sequencing is widely utilized for molecular breeding in several crops including rice. We performed whole genome resequencing of ten Korean rice accessions including six cultivars and four mutant lines. In total, 2,448 million raw reads were generated with over 58x coverage of Nipponbare genome. We mapped the reads from each of the ten accessions onto genomic sequence of japonica rice cultivar, Nipponbare. We detected 3,144,016 SNPs, which estimated to be one per 2.2kb on average. We found SNPs in genes that have been reported to be involved in rice flowering time regulation and bacterial blight resistance among ten rice accessions. Unmapped region against Nipponbare genome occupied about 1 ~ 2% in each accession. Over 50% of the unmapped region were found in the repeat region. The minimum length of gap in all accessions were 1bp and the maximum length of gap was 45,967bp in Ilpum. We also identified 3,497 possible gene loss events within these unmapped regions. The frequency of gene loss in each chromosome ranged from 33 on chromosome 5 to 913 on chromosome 11. The genetic variations we detected among ten rice accessions will provide invaluable resources for identification of genes associated with diverse traits of agronomical importance for molecular breeding.

In order to find new genetic sources of rice salt tolerance, we did screening with about 10,000 rice mutant lines created by Ac/Ds insertional mutagenesis. First, we raised rice seedlings with media soil on 0.7% NaCl solution and selected 71 putative salt tolerant lines and analyzed their Ds insertion sites. We tested their salt tolerance by growing seedlings on MS medium containing, 0 mM, 150 mM, and 250 mM NaCl. Also, their seedling salt tolerance were evaluated by growing on Yoshida nutritional solution containing 0.6% NaCl. Finally, we selected eight mutant lines showing increased seedling salt tolerance compared with wild type variety, Dongjin, repeatedly. We grow them in rice field and investigated their agronomic traits such as heading time, culm length, panicle length, and panicles per hill. Among them two lines which were named Salt10 and Salt23 and showed favorable agronomic characteristics were crossed with Dongjin for further genetic analysis and mapping the causative gene variation.

Progress in next-generation sequencing technologies have enabled discovery of massive amount of genome-wide DNA polymorphisms, single nucleotide polymorphisms (SNPs) and insertion-deletion (InDels), which are an invaluable resource to analyze genetic diversity in a population. We performed whole-genome resequencing of ten Korean rice accessions including six cultivars and four mutant lines. A total of 2,448 million raw reads was generated with 58-fold coverage and uniquely mapped to 87.5% of the Nipponbare as a reference genome. We identified 3,240,025 DNA polymorphisms including 2,867,878 SNPs, 151,845 insertions and 220,302 deletions between the Korean rice accessions and Nipponbare. We observed that in ten Korean rice accessions, the frequency of potential SNPs was estimated to be one per 2.1kb on Nipponbare (382Mb). According to annotation of DNA polymorphisms, 634,617 SNPs were found in gene region, and only 169,738 SNPs were occurred in coding region. Altogether, 86,251 non-synonymous SNPs were located on 76,891 genes. We also examined the cultivar-specific SNPs to select candidate SNPs which would have possibility of being associated with unique phenotype or agronomical trait of each cultivar. It was estimated that the portion of cultivar specific SNPs is 1~12% of the total SNPs. These DNA polymorphisms obtained from our result will provide an invaluable resource to identify molecular markers and genes associated with diverse traits of agronomical importance.

In plants, the Dof (DNA binding with One Finger) proteins are plant-specific transcription factors with a particular class of zinc-finger DNA-binding domain. The Dof genes have been predicted 30 different Dof genes in the rice Oryza sativa genome by phylogenetic analysis. The mostly Dof proteins contain a conserved region of 50 amino acids with a C2-C2 zinc finger motifs that binds a cis-regulatory element sequence 5’-T/AAAAG-3’. We found that a member of the DOF transcription factor family, Dof1 gene of rice, was expressed to wound from Ds insertion mutant population. Sequencing of the flanking regions of the transposon insertion site indicated that the gene-trap had been inserted near the front of the second exon of OsDof1 gene in chromosome 7. Genomic southern analysis revealed that mutant line contained a single copy of Ds gene trap. The Ds tagged rice mutant line, OsDof1::Ds, wound-inducible GUS expression was identified. To analyze the cis-acting elements, we constructed fusion genes with the OsDof1 promoter fused to the β-glucuronidase (GUS) reporter gene and transformed Arabidopsis and rice plants with these constructs. Wound-induced GUS expression was observed in the leaves of transgenic OsDof1::GUS rice and Arabidospsis plants. These results showed that, OsDof1 protein might be involved in stress responses and growth regulation in plant, might plays a role as a transcription regulator in stress response signal transduction pathways of plant.

MYB-like domain (MLD) gene is a transcription factor that plays a diverse role in plant development and in response to abiotic stresses. In this study, we isolated and developed CaMV35S::OsMLD rice lines and determined its expression pattern under abiotic stresses. It has Myb_CC_LHEQLE superfamily similar to most transcription factor genes but with a very unique binding domain of SHLQKYR in the C-terminal region. Overexpressing rice lines showed enhanced tolerance to salinity with elevated mRNA transcript. Additionally, mRNA transcripts were up-regulated by ABA, H2O2 and dehydration stresses. Further investigation in the enhanced tolerance to salinity showed an increased accumulation of proline and a decreased in malondialdehyde contents indicating that OsMLD gene may be involved in the regulation of proline and osmolytes during abiotic stresses. These results showed that OsMLD gene could be used in the development of rice intended for soil with salinity-related problem.

Rice seed storage proteins (SSPs) are accumulated in storage organelles of the endosperm during seed maturation. The SSPs from the rice seeds consist of glutelins as a major SSP, and prolamins and globulins comprise about the rest 20 % of the SSPs. To improve the nutritional quality of rice seeds or processing properties of rice flour, we are attempting to change the composition of the SSPs in rice seeds. For this purpose, we generated many transgenic rice plants, which show the altered levels of the SSPs, by using the RNA interference (RNAi). Accumulation of glutelins was 76% reduced in the GluA-RNAi lines. The Pro-RNAi lines revealed the reduced levels of prolamins to 36%. The protein level of globulins was 61% reduced in the Glb-RNAi lines. Interestingly, an obvious reduction of glutelins, prolamins, and globulins was not examined in the GluA:Pro:Glb-RNAi lines. This suggests that a reduction of a few SSPs could be compensated by the increases of other SSPs at the protein levels. We are also attempting to generate transgenic rice plants expressing both a high-molecular-weight (HMW) glutelin subunit and a low-molecular-weight (LMW) glutelin subunit. These manipulations of rice SSPs might be an important contribution on improving the functional properties of rice seeds.