국내에서 재배하여 생산되고 있는 상황버섯의 일종인 PMO-P4균주에 대한 ITS 영역의 염기서열 분석을 실시하였으며 목질 진흙버섯으로 잘 알려져 있는 P. linteus와 함께 RFLP분석을 통하여 상호 비교한 결과 PMO-P4균주는 P. baumii로 판명되었다. 이 결과를 토대로 이미 보고 되어 있는 Phellinus속 균주들과의 종간 ITS 영역의 상동성을 비교한 결과 48.6%-72.2%였으며 본 연구에서 비교한 종들 가운데서는 P. linteus와 상동성이 가장 높았으며 P. gilvus와 상동성이 가장 낮았다.

국내 밀 수량성 향상을 위해 이삭 길이가 길고 1수립수가 많은 장수형 계통의 품질과 이들 특성과 관련된 표지인자에 대한 평가를 수행하였다. 장수형 164계통의 회분, 단백질, 침전가, 습부율, 밀가루 입자 크기와 밀가루 색택 밝기의 평균은 금강밀보다 회분과 단백질함량이 높으며 습부율은 높고, 밀가루 밝기와 입자 크기는 비슷하였으나 침전가는 낮게 나타났다. 단백질의 질적 특성에서 단백질함량은 침전가, 습부율, 밀가루 입자 크기와 고도의 정의 상관을 보였고, 밀가루의 밝기와는 부의 상관을 나타냈다. 품질특성 관련 표지인자를 평가한 결과, 장수형 164계통은 모두 Glu-A3c, Wx-A1a, Wx-B1a, Wx-D1a의 유전자형을 나타내 금강밀과 동일하였다. 장수형 계통은 주로 Glu-A1c, Glu-B1c, Glu-D1a, Glu-B3g, Pina-D1b와 Pinb-D1b의 유전자형이 많았다. Glu-A1b과 Glu-B1b 유전자형은 단백질함량이 많고, 습부율이 높은 특성을 나타냈다. Glu-D1d, Glu-B3h과 Pinb-D1b 유전자형은 다른 유전자형에 비해 회분과 단백질함량이 많으며, 침전가와 습부율이 높고, 밀가루 입자가 크고, 밀가루의 색이 어두운 특성을 보였다. 이러한 결과를 통해서 장수형 계통은 수량성 증대를 위해 필요하고, 향후 용도별 품질 우수 자원의 특성을 집적하여 용도별 다수성 밀 품종개발을 위한 자원으로 활용하고자 한다.

국내 밀의 수량 증진을 위해 이삭 길이가 길고 1수립수가 많은 장수형 164계통(F8)을 육성하였고, 본 연구에서는 이들 계통의 주요 농업형질과 이들 특성과 관련 있는 표지인자에 대한 평가를 수행하였다. 장수형 계통은 모본인 금강밀과 비교했을 때, 단위면적당 수수와 리터중은 적고, 파종 후 출수까지 일수가 길었고, 간장, 수장, 1수립수와 단위면적당 생산량은 높게 나타났다. 농업 특성 관련 표지인자를 평가한 결과, 장수형 계통은 Rht-B1, Rht-D1, Vrn-B1, Ppd-A1, Ppd-B1 유전자 좌에서는 같은 유전자를 지닌 것으로 나타났다. 장수형 계통 중 Vrn-D1를 지닌 계통은 Vrn-D1a를 지닌 계통에 비하여 출수에 걸리는 시간이 길었지만, 이삭길이와 1수립수가 많은 것으로 나타났다. 하지만 Vrn-B1 유전자 변이는 장수형 계통의 농업형질의 차이가 없는 것으로 나타났다. 장수형은 Ppd-D1유전자 변이에 따른 간장이나 이삭 길이는 차이가 없었지만, 출수 일수와 수수는 Ppd-D1b를 지닌 계통이 많았지만, 1수립수, 천립중, 리터중과 수량은 Ppd-D1a를 지닌 계통이 높았다. 종실 특성을 나타내는 표지인자 변이는 출수 일수, 간장, 수장, 분얼이나 1수립수 및 수량에는 영향을 주지 않았지만 TaSus2-2B유전자의 Hap-L타입, TaGW2유전자의 Hap-6A-G타입과 TaCwi-A1a 가 각각의 대립 유전자형보다 천립중이 높게 나타났다. 향후 재배환경이 장수형의 농업형질 및 품질에 미치는 영향에 대한 평가가 필요하고, 만숙과 분얼이 적은 장수형의 단점을 보완하기 위한 지속적인 연구가 필요하다.

To understand the molecular mechanism of leaf morphogenesis in rice, ethylmethane sulfonate (EMS) treated Ilpoom mutant line with semi-narrow and adaxially rolled leaf phenotype was identified. The leaf rolling character is said to be more advantageous under high temperature and heat stress, and play as one of the defensive mechanisms. The F1 plants, generated from a cross of Ilpoom and mutant, showed normal phenotype. Genetic analysis of its F2 population suggested that the mutation was controlled by a single recessive gene with segregation ratio of 3:1. Using F2 mapping population derived from a cross of Ilpoom mutant and Milyang23, each chromosomes were screened with STS markers by the bulked segregant analysis (BSA) method. The candidate region was detected to a long arm of chromosome 1 near the centromeric region. Fine mapping of the locus is currently conducted. Moreover, other morphological characterizations of the mutant plants were identified. Cytological analysis of the leaf suggested that deformation of the bulliform cells led to the smaller size and less number of the bulliform cells, and caused leaf rolling trait.

Leaves are the organ for photosynthesis, respiration and transpiration, and have a major effect on crop yield. Therefore, leaf shape and structure are important agronomic traits in breeding for ideal type plant. We obtained a new abaxially rolled leaf mutant from Ilpum(Oryza sativa ssp. japonica) by the treatment of ethyl methane sulfonate(EMS). The abaxially rolled leaf mutant showed reduced plant height and panicle length, increased tiller number and panicle number than Ilpum. LRI(Leaf rolling index) analysis showed that the mutant have high value compared to the wild-type. In cross section analysis, the mutant was observed to have increased of bulliform cell number and size, and led to the outcurved leaf rolling. The phenotypes of the F1 plants derived from the cross between the mutant and Ilpum were normal. In F2 population, segregation ratio between the wild type and the mutant was 3:1. This genetic analysis indicated that leaf rolling is controlled by single recessive gene. Bulked segregant analysis(BSA) and genetic mapping were conducted using F2 population derived from the cross between mutant and Milyang23(Oryza sativa ssp. indica). According to the results, the gene was located on the long arm of chromosome2. Fine mapping is in progress.

Plastochron and phyllotaxy are important traits to determine plant architecture. A plastochron 1-6 mutant was derived from japonica rice cultivar Koshihikari treated with ethylmethane sulfonate (EMS). The plastochron 1-6 mutant showed reduced plant height, shorter internode length, smaller and more leaves than Koshihikari, its wild type. In addition, the mutant has abnormal panicle, abnormal seed and upper node tillers. The F1 plants between mutant and Koshihikari were normal. In F2 population, segregation ratio between the wild type and mutant was fitted to 3:1. This genetic analysis indicated that plastochron 1-6 is controlled by a single recessive gene. Bulked segregant analysis revealed that the gene was located on chromosome 10. Through sequencing analysis, we found that plastochron 1-6 mutant had a single nucleotide transition occurred in the first exon of LOC_Os10g26340 (encoding P450 CYP78A11). This work was supported by a grant from the Next-Generation BioGreen 21 Program (Plant Molecular Breeding Center No. PJ008125), Rural Development Administration, Republic of Korea.

Rice hulls remain closed throughout the ripening period to maintain internal humidity of the grains. An Open-hull sterile mutant was induced by N-methyl-N-nitrosourea(MNU) treatment on Sinsunchalbyeo rice, a japonica type. This mutant showed open hulls even in the ripening stages and fully mature grains. In addition, several altered characteristics were observed, including of narrowed palea, decreased grain size, partial pollen sterility and erect panicle. Microscopic analysis showed that the palea was positioned slightly inside the lemma, and the size of palea decreased in the mutant. Genetic analysis of F2 and F3 segregation populations derived from the cross between the Open-hull sterile mutant (Oryza sativa ssp. japonica) and Milyang23 (O. sativa ssp. indica) indicated that the Open-hull trait was controlled by a single recessive allele. The fine-mapping with STS (sequence tagged site) markers revealed that the mutant gene was located on the short arm of chromosome 3. We were able to narrow it down until 30.6Kb where three candidate genes were found.

Off-type rice plants occurring in farm fields cause yield loss due to competition with cultivated rice, in addition to hindering field management and harvest work. This study aimed to observe the agronomic characteristics and trace the origins of off-type rice plants using molecular markers. A total of 116 rice accessions, comprising 35 off-type plants collected from Korean farm fields, 19 Korean commercial cultivars, 12 Korean land races, and 50 weedy rice collections, were phenotyped and genotyped using selected SSR and Subspecies Specific (SS)-STS markers. The results showed that the plant height, culm length, and leaf length of off-type rice plants were larger than those of cultivated rice, which is the typical phenotype of weedy rice. However, off-type plants were highly sterile, as opposed to weedy rice, which were highly fertile. Genotype analysis with SSR and SS-STS markers revealed that off-type rice plants were heterozygous at most of the tested marker loci, suggesting that the off-type rice plants may have originated from natural outcrossing. The genotypes of off-type rice plants were closely related to both weedy and cultivated rice, and the phylogenetic analysis revealed that the relationship of the clustered group of offtype rice plants is intermediate between Indica type weedy rice and Japonica type commercial varieties. These results suggested that off-type rice plants collected in Korean farm fields might have originated from natural outcrossing between Indica type weedy rice and the cultivated Japonica type commercial varieties.

The early senescence mutant was isolated from the japonica rice Koshihikari through Ethyl-methane-sulfonate (EMS) mutagenesis. The early senescence phenotype was controlled by a single recessive gene, tentatively symbolized as es-k. Using an F2 population derived from a cross between the mutant and Milyang23 and molecular markers, we mapped the es-k locus to the long arm of chromosome 7 between STS markers 147-1 and 147-2 with a physical distance of 66-kb. The symptom of early senescence appeared even before heading, while appeared during ripening in wild-type. Physiological characteristics of the es-k mutant before initiation of senescence was similar to the wild-type. However, after heading, es-k mutants started to exhibit a significant decrease in chlorophyll and soluble protein content compared to the wild-type. The wild-type leaf color appeared normal irrespective of temperature treatment, while the leaf of es-k mutant appeared pale-green at the low temperature and dark-green at the high temperature. During dark-induced senescence, mutant did not show significant differences compared to normal type. The results show that es-k is sensitive to temperature but not to light.

Two sugary mutants, Hwacheong sugary-1 (Hsu1) and Hwacheong sugary-2 (Hsu2) were obtained by chemical mutagenesis from japonica cultivar, Hwacheongbyeo. Sugary mutants exhibited wrinkled and translucent grain with high soluble sugar content. In addition, amber-colored endosperm of sugary mutants was loosely packed due to abnormal starch granules compared to densely packed wild-type. Especially, the grain of Hsu2 mutant was less wrinkled than that of Hsu1, thus Hsu2 can be polished easily. Previous studies reveal that su1 mutant was resulted from mutation in gene for a debranching enzyme, isoamylase but the sequence of the mutated gene has not been identified. To identify the sequence of sugary genes, the map-based cloning strategy was applied. The genetic study revealed that the phenotype of Hsu2 mutant was controlled by two recessive genes. Interestingly, one of the genes was located on chromosome 8 at the position of isoamylase which was known as su-1. This indicates that mutation in isoamylase gene causes sugary endosperm characteristics. However we found different mutation points between the Hsu1 and Hsu2. The point mutation in Hsu1 was occurred at 10th exon whereas the other mutation related with Hsu2 was occurred at 15th exon. As mentioned above, the Hsu2 mutant has less wrinkled shape and less soluble sugar content than the Hsu1 mutant. Thus, we hypothesize that the other gene controlling Hsu2 mutant phenotype may have a role in weakening the effect of the su-1. Further study on the other gene associated with the Hsu2 phenotype is in progress.

The early senescence mutant was isolated from the japonica rice Koshihikari through Ethyl-methane-sulfonate(EMS) mutagenesis. The early senescence phenotype was controlled by a single recessive nuclear gene, tentatively symbolized as es-k. Using phenotypic and molecular markers, we mapped the es-k locus to the long arm of chromosome 7 between STS markers 147-1 and 150-1, a physical region of 370-kb. The symptom of early senescence appeared even before heading, while appeared after heading in those of the wild-type rice during senescence. Early stage physiological characteristics of the es-k mutant was similar to that of the wild-type. However, after heading, es-k mutants started to exhibit a significant decrease in chlorophyll content, soluble protein content 10 days earlier compared to normal type. To characterize the interaction with the environment factors, experiments were carried out under controlled temperature and light conditions, respectively. The wild-type leaf color appeared normal irrespective of temperature treatment, while the leaf of es-k mutant appeared pale-green at the low temperature and dark-green at the high temperature. During dark-induced senescence, mutant did not show significant differences compared to normal type. The results show that es-k is sensitive to temperature but not to light.

Rice lax panicle (lax) mutant had defect in early inflorescence differentiation and lateral branch formation and exhibitedfewer numbers of rachis branches and spikelets in the panicle. The mutant also had abnormality in floral organ formation. Whereas, the spotted leaf 6 (spl6) mutant produced lesions in absence of pathogen. Analysis with a lax spl6 double mutant indicated both genes are controlled by single recessive factor and linked on chromosome 1 with 7 centiMorgan map distance. The lax gene was fine mapped within the 261.3 kb region between RM7594 and RM5389 that predicted 10 open reading frames (ORF) as candidate for lax gene. Sequencing of the candidates in the lax mutant revealed a substitution of nucleotide T by G corresponding to an amino acid substitution from serine (S) to alanine (A) at the 117th position within the coding region of the candidate ORF bhlh123. The intronless 1080 bp cDNA of LAX gene contains an ORF of 215 amino acids and encoded a basic helix-loop-helix transcription factor. Analysis of a 5.1 kb genomic fragment of the lax gene from homozygous dominant progeny which corresponded to indica cultivar resulted in a long deletion of 24 nucleotides in the upstream of LAX cDNA. (This research was supported by the National Research foundation of Korea, Grant 0070065).