We have previously investigated the proteome changes of rice leaves under heat stress (Lee et al. in Proteomics 2007a, 7:3369- 3383), wherein a group of antioxidant proteins and heat shock proteins (HSPs) were found to be regulated differently. The present study focuses on the biochemical changes and gene expression profiles of heat shock protein and antioxidant genes in rice leaves in response to heat stress (42°C) during a wide range of exposure times. The results show that hydrogen peroxide and proline contents increased significantly, suggesting an oxidative burst and osmotic imbalance under heat stress. The mRNA levels of chaperone 60, HSP70, HSP100, chloroplastic HSP26, and mitochondrial small HSP responded rapidly and showed maximum expression after 0.5 or 2 h under heat stress. Transcript levels of ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR) and Cu-Zn superoxide dismutase (Cu-Zn SOD) showed a rapid and marked accumulation upon heat stress. While prolonged exposure to heat stress resulted in increased transcript levels of monodehydroascorbate reductase, peroxidase, glyoxalase 1, glutathione reductase, thioredoxin peroxidase, 2-Cysteine peroxiredoxin, and nucleoside diphosphate kinase 1, while the transcription of catalase was suppressed. Consistent with their changes in gene expression, the enzyme activities of APX and DHAR also increased significantly following exposure to heat stress. These results suggest that oxidative stress is usually caused by heat stress, and plants apply complex HSP- and antioxidant-mediated defense mechanisms to cope with heat stress.

포장에서 생육된 잔디 포복경을 이용한 Agrobacterium 형질전환에 있어서 큰 제한인자였던 곰팡이 오염을 제거할목적으로 포복경 조직에 대한 새로운 살균법을 개발하고자하였다. 여러 가지 살균방법 중에서 30% NaOCl로 15분간처리한 다음 0.1% HgCl2로 25분간 처리 했을 때 포복경절편체의 생존율이 높았으며, 0.1% HgCl2로 처리시 800mbar의 진공처리를 5분간 실시했을 때 가장 효과적이었다.또한 Agrobacterium과 공동배양 시 2.5 mg/l의 amphotericinB를 첨가해 준 배지에서 배양했을 때 가장 높은 생존율을나타내었다. AmB의 처리는 Agrobacterium의 생장에 영향을 미치지 않았다. 또한 살균된 포복경으로 부터 신초의재분화에도 영향을 미치지 않았으며 곰팡이 오염만을 효율적으로 억제하는 것으로 나타났다. 이러한 결과는 포장에서 대량으로 생육시킨 잔디 포복경을 이용한 Agrobacterium형질전환 시 그 효율을 증가시키는데 큰 기여를 할 것으로추측된다.

본 연구는 국내산 침엽수로부터 천연 항균화합물 개발을 목표로 미송 및 편백으로부터 추출물을 확보 하여 푸른곰팡이병의 원인균인 Trichoderma spp. 5종을 대상으로 항균활성을 테스트하고 GC/MS를 이 용하여 항균화합물을 탐색하였다. 미송 추출물은 Trichoderma spp.에 대해 1,000 ppm에서 저해 활성을 나타냈으며, 4,000 pp에서는 T. viride>T. harzianum>T. aggressivum 순으로 70.1, 67.3, 64.7% 의 높은 항균활성을 나타냈다. 편백 추출물도 1,000 ppm에서 항균활성을 나타냈고 4,000 ppm에서 T. viride>T. harzianum>T. aggressivum 순으로 63.2, 59.3, 59.1%의 높은 항균활성을 나타냈다. 그러나 1,000 ppm의 미송추출물과 1,000 ppm의 편백추출물을 각각 9:1, 8:2, 6:4, 2:8 (w/w) 비율의 혼합제 제로 만들어 Trichoderma spp.에 처리하였을 때 미송추출물 1,000 ppm 및 편백추출물 1,000 ppm 각 각의 단일추출물보다 낮은 항균활성을 나타냈다. Trichoderma spp. 5종에 대해 높은 항균활성을 나타 내는 미송추출물에서는 2-Isopropoxy-ethylamine 46.5%, epifluorohydrin 8.6%, trans-2,3-Dimethyloxirane 7.6%, (IR)-(-)-Myrtenal 6.0%, 2-Methoxy-4-Vinylphenol 3.9%, benzaldehyde 2.8%가 함유되어 있었고, 편백추출물에서는 α-Terpinenyl acetate 14.9%, Sabinene 10.9%, dl-Limonene 9.6%, α-Terpinolene 7.5%, α-Pinene 7.1%가 함유된 것이 확인되었다.

Antibiotics marker-free with herbicide-resistant tall fescue plants were produced through Agrobacterium: mediated transformation system. Embryogenic calli derived calli were infected with Agrobacterium tumefaciens strain EHA105 harboring the pCAMBIA3300 vector containing the bar and the CP4-EPSPS genes. The PPT-resistant calli and plants were selected with 10 ㎎/L PPT, respectively. Soil-grown plants were obtained about 14-16 weeks after Agrobacterium-mediated transformation. Genetic transformation of the regenerated plants growing under selection was demonstrated by PCR, and Southern blot analysis revealed that one copies of the transgene were integrated into the plant genome of each transgenic plant. Expression of the bar and CP4-EPSPS genes in transgenic plants was confirmed by Northern blot analysis and CP4-EPSPS genes in transgenic plant ELISA uses antibody protein by ELISA Assays. Transgenic plants sprayed of two herbicides with glufosinate ammonium or glyphosate remained green and healthy. We therefore report here a successful and reliable Agrobacterium-mediated transformation of two herbicide-resistances and this method may be useful for routine transformation and has the potential to develop new varieties of tall fescue with several important genes.

Environmental stress is a growing problem for the productivity of forage crops. Reactive oxygen species (ROS) formation due to several abiotic stresses is a fundamental process that interrupts several physiological processes and causes a significant reduction on growth and yield of many forage crops. Molecular breeding such as genetic transformation has become a popular biotechnological tool for improving forage quality as well as improves tolerance to various abiotic stresses. As a first step of genetic transformation in tall fescue, we established an efficient Agrobacterium-mediated genetic transformation protocol using mature seed-derived embryogenic callus. After optimization of the transformation system, several genes of interest have been used to generate abiotic stress tolerant forage grasses. We generated transgenic tall fescue plants expressing NDPK genes under the control of the oxidative stress-inducible SWPA2 promoter. Transgenic plants showed enhanced tolerance to several abiotic stresses. Results in the current study, suggest that NDPK mediated multiple stress tolerance by increasing the expression of genes involved in antioxidant and protective functions, possibly through activation of an MAPK cascade.