Background : The Schizonepeta which is characterized by short growth period is used for the pedicel as a medicinal plant. Its main ingredients are essential oil, monoterpenoid, and flavonoid. Major effects include fever, pain, anti-inflammation, and anti-allergy. There are no varieties developed so far, and it is necessary to develop standard varieties to supply domestically good varieties. In this study, the growth and yield characteristics of the genetic resources collected for cultivating good-quality varieties were tested. Three strains were classified into early, medium, and late life. Methods and Results : The research was carried out in the test packaging of the Medicinal Resources Research Institute (Hamyang) in Gyeongnam province. It was harvested in late May, early June, and mid June by flowering season. The harvest time was mid June, late June, mid July, late July, mid August, and late August. Flowering, growth characteristics and yield were investigated. Growth characteristics showed a tendency to increase with the delay of flowering and harvesting time, such as plant height, leaf length etc. As the flowering time and harvesting time were delayed, the number of trees increased. The selected early line showed 89.4 ㎝ in plant length, 38.3 g grain weight, medium line 69.5 ㎝, 61.0 g, late line 136.4 ㎝, 111.2 g. Conclusion : When the cultivars are selected for the selected strains, it is expected that the cultivars with high physiological activity characteristics will be able to develop the cultivars as high quality varieties and high yield varieties.

It is important for radish to have late flowering characteristics especially in the case of spring and winter cultivars. To understand late flowering characteristics of radish at the molecular level the flowering time genes of two radish lines (NH-JS1 and NH-JS2) with different flowering time were compared by re-sequencing their genomes. There were a total of 872,587 SNPs and 194,637 INDELs between the two lines. The SNP density of each chromosome was relatively uniform throughout, but the region with low SNP density was found at the end of R3 and the middle of R9. To compare the flowering time genes of the two lines, we first looked for the flowering time genes in radish using Arabidopsis thaliana flowering time genes. As a result, homologs of radish were found for most flowering time genes, but FRIGIDA was not found. Among 224 radish flowering time gene-homologs found, 97 genes showed more than one sequence difference (SNP or INDEL) between the two lines, and 127 genes had no difference. In particular, no sequence differences were found in FT, CO, and FLC, core flowering time control genes. Rs350520 (FVE), Rs193800 (CURLY LEAF) and Rs255320 (ATX1) with more than 100 sequence variations were expected to have a significant effect on flowering time difference between the two lines. These results will be of great help in understanding the flowering timing difference between the two lines at the molecular level.

The transition from vegetative growth to flowering is a major developmental switch in the plant cycle and the timing of flowering is very critical for reproduction of plant species. In transition to flowering in plants, Flowering locus C (FLC) is one of the crucial factors. Here, we showed How the stability and activity of FLC are regulated by sumoylation mechanism. By pull-down assay, we showed that FLC interact with E3 SUMO ligase in vitro and vivo. And we showed that FLC is sumoylated in vitro condition with AtSUMO1 protein. In transgenic plants with overexpression of FLC and inducible expression of AtSIZ1, sumo E3 ligase led to increase of FLC protein level and delayed the post-translation degradation of FLC indicating that Arabidopsis E3 sumo ligase AtSIZ1 stabilizes FLC. Also, the plants with overexpression of mutant FLC (K154R, a mutation of the sumoylation site on FLC) flowered considerably earlier than plants with overexpression of FLC but comparable with wild type indicating that sumoylation is a important part for function of FLC. Our data indicate that the sumoylation of FLC is critical for its role in the control of flowering time.

Flowering time is a important agronomic trait for grain production in rice. So the control of flowering time is a critical step. In Arabidopsis, expression of certain key flowering gene such as FLOWERING LOCUS C (FLC) is known to be epigenetically regulated by chromatin modification through Enhancer of Zeste[E(z)], a histone methyltransferase, that core component of repressive complex, polycomb repressive complex2(PRC2). However, the chromatin mechanism involved in the regulation of rice flowering genes is presently not well known. Here we show that predict coding region of a intronic LncRNA[termed rice COLDAIR(OsCOLDAIR)], which is expected to associate with a component of PRC2, is predicted at rice FLC gene. And additionally we suggest interaction of histone methyltransferase and E3 SUMO ligase that indicate possibility of interaction with rice E(z) gene and rice E3 SUMO ligase. Our study contribute to control of rice flowering time by observing two factor that can regulate expression of related of rice FLC gene.

FLOWERING TIME CONTROL PROTEIN, FPA gene encode RNA Recognition Motif (RRM) domain protein and plays important roles in flowering time control in Arabidopsis. Floral transition is significant for reproductive products in all flowering plants. However, little is known about the functions of Medicago autonomous pathway gene. We had cloned the FPA gene on Medicago based on the sequence similarity of Arabidopsis FPA sequence. The RT-qPCR analysis of MtFPA expression patterns showed that the MtFPA transcripts accumulated ubiquitously in roots, leaves, stems, flowers, and pods. When fused to the green fluorescence protein, MtPFA-GFP was localized in the nucleus as speckle pattern of protoplast from Arabidopsis. To examine the function of MtFPA, 35S::MtFPA transgenic plants were generated in Arabidopsis late flowering mutant background, fpa-2. Overexpression of MtFPA specifically caused early flowering under long day conditions compared with non-transgenic plants. In MtFPA transgenic lines, AtFLC expression were down-regulated whereas the floral integrators, AtFT and AtSOC1 were up-regulated as compare with control plant. As these results, MtFPA suggest that is a functional ortholog of the Arabidopsis and may play an important role in the regulation of flowering transition in Medicago.

FT is one of the major floral activator in photoperiod-dependent flowering pathway. To understand the role of FT homologs in flowering time control of short-day plant soybean, we identified ten soybean FT genes and named GmFTs. Phylogenetic analysis revealed that ten GmFT genes were further categorized into three subclades. Gene expression analysis showed that the most GmFT genes are mainly expressed in leaves. The expression of GmFT2a, GmFT2b, GmFT5a, and GmFT6 was strongly induced under the floral inductive short-day condition, but GmFT4 exhibited opposite expression pattern compared to those of GmFT2a, GmFT2b, GmFT5a, and GmFT6. To understand roles of GmFT genes in flowering, we generated Arabidopsis transgenic plant overexpressing GmFT genes. Both 35S:GmFT2a and 35S:GmFT5a transgenic plants showed extremely early flowering. In contrast, overexpression of GmFT4 delayed flowering of transgenic plants compared to wild type Arabidopsis. The results indicated that GmFT2a and GmFT5a might function as floral activators, while GmFT4 has an opposite function in soybean flowering. Moreover, domain swapping approaches between GmFT2a and GmFT4 revealed that the substitution of the segment B region alone, which is located in 4th exon, was sufficient to change the function of GmFT2a to floral repressor and GmFT4 to floral activator. The results suggested that soybean FT homologs have been functionally diversified during evolution and might play different roles in photoperiod-dependent flowering of soybean.

In rice (Oryza sativa L.), there is a diversity in flowering time that is strictly genetically regulated by plenty of genes. The floral transition from vegetative to reproductive development is a very important step in the life cycle of a flowering plant. Orthologous genes, which are homologous genes that diverged after a speciation event, generally maintain a similar function in different species. with a McDonald-Kreitman Test (MKT), we examined more than 10,000 orthologous genes between rice (Oryza sativa) and Brachypodium (outgroup), based on different phenotypic groups, to find some fast evolutionary genes of rice flowering time. Three groups with early flowering time (group 1), midium flowering time (group 2) and late flowering time (group 3) were separated and each group was examined for McDonald-Kreitman Test (MKT). Total 70 fast evolutionary genes under a positive selection were found in the three groups, and 14, 42 and 14 genes were specific existed in group 1, 2 and 3, respectively. Annotation of these genes were conducted and the predicted functions were also surveyed. In addition, network analysis of these characterized genes were also investigated to infer related pathways. And also, the association study between the one early flowering factor and the flowering time phenotype was performed and indicated that this gene is significantly correlated with flowering time in rice. These results suggest that using this orthologous based method, we could find some important candidate genes underlying flowering time regulations.

To develop molecular markers for late flowering time in radish we performed QTL-seq analysis in which whole genomes are sequenced and SNPs between two groups showing opposite phenotypes in F2 population are analyzed to find regions or QTLs involved in a trait of interest. Two inbred lines (NH-JS1 and NH-JS2) showing opposite phenotypes of flowering time were selected to generate F2 population for the analysis. NH-JS1 showed late flowering time whereas NH-JS2 early flowering time. Genomic DNA from the two lines were extracted and sequenced. In addition F2 population from F1 between NH-JS1 and NH-JS2 was generated and flowering time phenotypes of 180 F2 plants were analyzed. We selected 11 plants with late flowering time and 12 plants showing early flowering time. We extracted DNA from each individuals from the two groups and bulked them to generate two bulked DNA samples that are subject to whole genome resequencing. Preliminary analysis of SNP data from the resequencing showed that there may be several QTLs involved in flowering time control in radish.

In rice (Oryza sativa L.), there is a diversity in flowering time that is strictly genetically regulated. The floral transition from vegetative to reproductive development is a very important step in the life cycle of a flowering plant. Although the genetic pathway for short-day flowering in rice is relatively well understood, the naturally occurring molecular mechanisms underlying flowering time diversity of the cultivated rice are still not clear. Resequencing of 295 rice accessions including 137 HS and 158 KB rice accessions, was recently finished with an average of approximately 10x depth and > 90% coverage. A wide range of variation in flowering time was observed within a diversity research set of 295 accessions ranging from 28 to 72 days. GWAS was performed using the resequencing data to investigate the candidate genes associated with flowering time in rice. Our GWAS result suggests that two SNPs in the promoter or 3’ UTR of the ‘Arabidopsis CO’ homolog FBH1 are potentially associated with early flowering. The new SNPs found in the FBH1 locus would be useful in developing markers to screen the varieties with early flowering time in the future molecular breeding.

개화는 식물이 영양생장에서 생식생장으로 전환되는 중요 한 발달 단계로 유전학적, 분자생물학적 접근 방법을 통하여 개화 기작을 이해하기 위한 연구들이 수행되었다. 개화시기 조절에 관한 연구는 주로 애기장대를 이용하여 진행되어 왔 으며 이를 바탕으로 춘화처리 경로, 자발적 경로, 광주기 의존 적 경로, 식물 호르몬인 지베렐린 연관 경로들이 밝혀졌고 이 들 경로와 관련된 다양한 유전자들이 보고되었다. 이들 중 춘 화처리 및 자발적 경로는 개화억제 유전자인 FLC 발현 조절 을 통해 개화시기를 조절한다고 밝혀졌다. 최근 연구에 따르 면 chromatin-remodeling 인자들인 FLD, FVE, VIN3, VRN1, VRN2, FRI 등과 FCA, FPA, FLK등의 RNA 결합단백질과 FY등의 다양한 RNA processing 관련 단백질들이 FLC 유전자 발현을 조절하고 있는 것으로 보고되고 있다. 이와는 다르 게 광주기성 개화유도는 FLC와 다른 독립적인 경로를 가지 고 있다. 광수용체로부터 시작된 신호는 개화촉진인자 CO 유 전자를 활성화 시키고 하위 유전자 FT 발현을 유도한다. FT 단백질은 FD 단백질과 상호작용하여 AP1으로 신호를 전달 하며 FLC에 의한 개화 억제 신호와 경쟁적으로 상호작용을 하며 개화시기를 조절하게 된다. 이들 각 경로로부터 개화시 기를 조절하는 유전자 연구들을 바탕으로 작물에서 개화시기 에 관여하는 유전자를 도입하거나 발현을 조절함으로서 작물 의 개화시기에 변화를 주는 연구들이 지속적으로 활발하게 수행되고 있다. 작물에서 개화시기 조절은 생산량, 바이오매 스 등에 영향을 주는데 최근에 들어서는 기후변화에 의한 이 상온도로 개화시기가 빨라지거나 늦어지는 경향을 보이고 있 다. 따라서 전통육종과 더불어 유전자를 이용한 개화시기 조 절은 변화하는 환경에 적응할 수 있는 작물을 개발하는데 중 요한 역할을 할 수 있을 것이다.

Flowering is exquisitely regulated by both promotive and inhibitory factors. Molecular genetic studies with Arabidopsis have verified several epigenetic repressors that regulate flowering time. However, the roles of chromatin remodeling factors in developmental processes have not been well explored in rice. We identified a chromatin remodeling factor OsVIL2 (O. sativa VIN3-LIKE 2) that promotes flowering. OsVIL2 contains a plant homeodomain (PHD) finger, which is a conserved motif of histone binding proteins. Insertion mutations in OsVIL2 caused late flowering under both long and short days. In osvil2 mutants OsLFL1 expression was increased, but that of Ehd1, Hd3a and RFT1 was reduced. We demonstrated that OsVIL2 is bound to native histone H3 in vitro. Chromatin immunoprecipitation analyses showed that OsVIL2 was directly associated with OsLFL1 chromatin. We also observed that H3K27me3 was significantly enriched by OsLFL1 chromatin in the wild type, but that this enrichment was diminished in the osvil2 mutants. These results indicated that OsVIL2 epigenetically represses OsLFL1 expression. We showed that OsVIL2 physically interacts with OsEMF2b, a component of polycomb repression complex 2. As observed from osvil2, a null mutation of OsEMF2b caused late flowering by increasing OsLFL1 expression and decreasing Ehd1 expression. Thus, we conclude that OsVIL2 functions together with PRC2 to induce flowering by repressing OsLFL1. Transgenic plants over-expressing OsVIL2 flowered early. In addition, they were taller and ticker due to increased in cell number, resulting in yield increase. The same phenotypes were observed from OsVIL4 knockout mutants. These indicate that OsVIL4 represses OsVIL2 function by directly binding to the protein.

To examine the trend on the flowering time in some weather flora including Prunus serrulata var. spontanea, Cosmos bipinnatus, and Robinia pseudo-acacia in Busan, the changes in time series and rate of flowering time of plants were analyzed using the method of time series analysis. According to the correlation between the flowering time and the temperature, changing pattern of flowering time was very similar to the pattern of the temperature, and change rate was gradually risen up as time goes on. Especially, the change rate of flowering time in C. bipinnatus was 0.487 day/year and showed the highest value. In flowering date in 2007, the difference was one day between measurement value and prediction value in C. bipinnatus and R. pseudo-acacia, whereas the difference was 8 days in P. mume showing great difference compared to other plants. Flowering time was highly related with temperature of February and March in the weather flora except for P. mume, R. pseudo-acacia and C. bipinnatus. In most plants, flowering time was highly related with a daily average temperature. However, the correlation between flowering time and a daily minimum temperature was the highest in Rhododendron mucronulatum and P. persica, otherwise the correlaton between flowering time and a daily maximum temperature was the highest in Pyrus sp.

MADS-box genes encode a family of transcription factors which involve in diverse developmental processes in flowering plants. Because flowering time determines the timing of transition from vegetative to reproductive stage and time to harvest, it would be a significant trait not only to plant it-self but also to breeders. The sequences and gene structures of Arabidopsis MADS-box genes are conserved in model legumes. However, complex genome structure, in soybean, makes it difficult to identify actual genes related to flowering and maturity, although QTL researches have been generally conducted. Therefore, we hypothesized that putative MADS-box genes around the flowering time and maturity QTLs would be candidate genes for those loci. In this study, after surveying 84 QTLs highly associated with maturity and flowering, the QTLs were selected if they were located near 473 putative MADS-box genes. Finally, we found the highly associated 16 SNPs at non-coding region of the putative MADS-box gene around the QTL in 28 late maturity cultivars and 28 early maturity cultivars. Furthermore, by comparing genetic diversity in the cultivated soybeans of late and early maturity groups as well as 20 wild soybeans, selection pattern during domestication was predicted.

전초로 되고 있는 바위솔은 일임성 식물이다. 본 연구는 정식 시기가 바위솔의 생장 및 개화에 미치는 영향을 추적하여 출하시기를 조절할 수 있는가에 대한 정보를 얻고자 본엽이 15매 정도인 유묘를 5월 30일, 6월 30일, 7월 30일에 정식하여 추대가 일어나는 8월 25일부터 매일 암기중단 처리하면서 8월 25일부터 4주 간격으로 생장과 개화 반응을 조사하였던 바 그 결과를 요약하면 다음과 같다. 1. 초장과 화서장은 정식시기가 늦어질수록 길어졌던 반면, 엽과 포엽수 및 경직경은 6월 30일 정식시 가장 많거나 굵어지는 경향을 보였다. 2. 소화중은 정식시기가 늦어질수록 많아졌던 반면, 엽과 포엽중, 경중, 근중, 지상부중과 전체건물중은 6월 30일 정식시가장 많았다. 3. 형성되는 소화수는 6월 하순경에 정식할 경우 가장 많았으나, 암기중단 처리로 인하여 정식시기에 관계없이 소화의 개화는 전혀 일어나지 않아 개화개체 비율은 전무하였다.

일임성 식물인 바위솔은 소화의 개화로 고사하는 특성을 가지고 있다. 본 연구는 추대로 형성된 화서의 소화의 개화를 억제하고자 8월 25일부터 매일 암기중단 처리를 가하면서 8월 25일부터 10월 4일까지 2주 간격 (8/25, 9/8, 9/22, 10/4) 으로 총 4회에 걸쳐 화서의 제거시기를 달리 처리하면서 처리 전후의 생장 및 형태 변화를 11월 2일까지 추적하였던 바 그 결과를 요약하면 다음과 같다. 1. 초장, 화서장 및 엽과 포엽수는 화서제거 때까지 급격히 증가하여 화서가 제거된 것과 제거되지 않은 처리간에 차이가 많았으나, 경직경은 처리간 차이가 미미하였다. 2. 9월 하순까지 처리에 의하여 제거되는 화서는 현저히 증가하였으며 잔존하는 엽과 포엽중, 소화중, 지상부중 및 전체 건물중은 초장, 화서장 및 엽과 포엽수와 유사한 반응을 보인 반면, 경중과 근중은 경직경과 유사한 반응을 보였다. 3. 소화는 화서제거 때까지 급격히 증가하였으나 화서제거로 인하여 거의 제거되었다. 화서제거 때까지 형성된 소화는 암기중단 처리로 인하여 개화되지 않았다. 4. 화서제거로 잔존하는 소화가 거의 없기 때문에 화서제거 이후에는 온도관리에 집중되어야 할 것으로 판단되었다.

개화후 강우 시기가 홍화의 생육과 종실의 품질에 미치는 영향을 구명하기 위해 시험을 수행한 결과는 다음과 같다. 개화후 강우 시기에 따른 지상부 및 꽃 봉오리 병해 발생 정도는 각각 3.3, 1로서 영향을 미치지 않았다. 등숙 비율은 주경은 개화후 1~5일 강우시 37.4%, 1차 분지는 개화후 6~10일 강우시 63.0%로서 가장 낮았다. 10a당 수량은 무강우의 327kg/10a에 비해 개화후 6~10일과 개화후 11~15일 강우시 282~281kg/10a으로서 각각 14% 감소되었다. 종실의 색도(명도=L)는 개화후 21~25일 강우시 73.5, 26~30일 강우시 69.9로서 무강우 79.3에 비해 크게 낮아졌다. 이상의 결과에서 볼때 수확기 강우에 의한 종실의 품질 손실 방지를 위해서는 개화후 25일까지는 수확을 해야 할 것으로 사료된다.