Most vacuolar proteins are synthesized on the endoplasmic reticulum (ER) as a proprotein precursor and then transported to vacuoles. In vacuoles, they are converted into the respective mature form. TaVPE1 and TaVPE2 were isolated from the cDNA library that was prepared from the wheat kernels at 16 and 18 days after fertilization (DAF). Additionally, putative TaVPEs (TaVPE3, TaVPE4) were isolated by inverse PCR (IPCR) using GrainGenes database. Each open reading frame (ORF) encodes 495, 497, 495, 456 amino acids, respectively. TaVPEs were closely related in respect to peptide comparisons and their sequence homologies were ranged from 84% to 93%. The TaVPE genes showed various expression patterns in response to exogenous treatment of phytohormones. The transcript of TaVPE1 was detected slightly and steadily after exposure to all phytohormones and the accumulation of TaVPE2 transcript was increased from 24 hours in NaCl treatment. The transcript of TaVPE3 was increased from 48 hours in response to H2O2 and decreased after exogenous application of ABA and salicylic acid. In case of TaVPE4, the transcript of TaVPE4 were weakly detected all time points of each phytohormone treatment.

Pectin, one of the main components of plant cell wall, is deesterified in muro by PME (Pectin methylesterase). PME activity is particularly regulated by inhibitor proteins known as the pectin methylesterase inhibitor (PMEI). The PMEI plays a key role in wounding, osmotic stress, senescence and seed development. However, the role of PMEI in plant species still remains to be demonstrated especially in wheat. To facilitate the studies on the expression of the TaPMEI gene, RT-PCR was performed using leaf, stem and root tissues in response to exogeneous application of phytohormones and abiotic stress treatments. Transcription of the TaPMEI gene was significantly induced in NaCl, H2O2 and SA treatments, and reduced when plants were treated with ABA. To elucidate the subcellular localization of the TaPMEI protein, TaPMEI:GFP fusion construct was transformed into onion epidermal cells by particle bombardment. The fluorescence signal was exclusively detected in cell wall of the cells. In order to obtain recombinant TaPMEI protein, the TaPMEI protein, expressed in E.coli as a MBP (~42.5 kDa) fusion protein recombinant. Purification and functinal analysis of TaPMEI as an inhibitor of PME activity are described.

It was previously pointed out that mutation is the ultimate source of variation. Adequate variation is needed for plant breeding if there is a limitation in natural genetic resources. When the ionizing radiation has been known to cause chromosomal and genomic alternations, it is widely used for inducing mutagenesis. The electron beam as an ionizing radiation is the principal physical mutagens that induces mutation and effectively used in plant breeding. Since dose-response relationships of electron beam in plant species are rarely known, we investigated the seed germination rate and early seedling growth of irradiated seeds of creeping bentgrass (Agrostis palustris Huds., cv Penn-A1) with various electron beam irradiating conditions (1, 1.3, 2 MeV at both 0.03 mA and 0.06 mA with dose of 100 Gy (Gray) and 0.03, 1, 1.3, 2 MeV at 0.03 mA with dose of 200 Gy, respectively) using electron accelerator at Korea Atomic Energy Research Institute. The growth parameters in terms of shoot length, primary root length, and secondary root length showed similar response between 0.06 / 1 (mA / MeV) at 100 Gy and 0.03 / 0.3 (mA / MeV) at 200 Gy. Bentgrass seed germination was mainly affected by the intensity of irradiated dose (Gray). Germination rate was lowered as the irradiated dose increased. On the other hand, early seedling growth was mainly governed not by the dose of radiation but by voltage.

Decomposition of green manure is necessary for the nutrient supply in farm soil. Hairy vetch as a green manure is superior to other winter legumes in terms of wintering ability and N accumulation. This experiment was carried out to investigate the decomposition and N release of hairy vetch and its effect on rice production as the following crop in paddy field. Decomposition of hairy vetch placed by soil depth of 0, 10 and 20cm at transplanting time was investigated by mesh bag method, which was enclosed chopped residue in mesh bags. The fate of 15 N derived from 15 N-labeled hairy vetch was investigated at harvest in three levels of N fertilization. Grain yield of the transplanted paddy rice cultured with hairy vetch as starter N were compared with that of applying urea as starter N in the field. Hairy vetch residue decomposed very rapidly both in transplanted and dry-seeded paddy field. In transplanted paddy field, hairy vetch residue lost 72-81 % and 86-90% of its weight after one and five month, respectively, as affected by incorporation depth. The C/N ratio of the decomposing vetch residue increased sharply during the early stages and after then, decreased slowly. The amounts of N and P released from the vetch were about 90% and 97% of initial content after one month, respectively. Recoveries of hairy vetch-15 N by rice plant were 30.6, 34.6 and 35.7% in 0, 6 and 12 kg urea-N 10 a-l application, respectively, indicating that N fertilization increased the recovery of hairy vetch. 15 N. Hairy vetch residue incorporated as starter maintained significant N H4 + -N concentration in soil water of plow layer until effective tillering stage. Grain yield in the plot applied with hairy vetch was not significantly different from that in the plot with urea. We concluded that hairy vetch incorporation could substitute starter N fertilization and showed possibility to reduce N amount of top-dressing.g.g.