ABA는 식물에서 비 생물학적 스트레스 내성에 관여하는 중 요한 식물 호르몬이다. 애기장대의 group A bZIP 전사인자는 ABA 신호전달 과정에 중요한 역할을 한다고 알려져 있다. 그러나 벼에서는 group A bZIP 전사인자의 기능이 잘 알려져 있지 않다. 따라서 우리는 벼에서 group A bZIP 전사인자인 OsABF3 (Oryza sativa ABA responsive element binding factor 3)를 연 구하였다. 이를 위해 벼의 다양한 조직과 다양한 스트레스(가 뭄, 염분, 저온, ABA, 산화 스트레스)에 따른 OsABF3 발현 패턴을 분석하였다. 또한 maize의 원형질체에서 GFP fusion 벡터를 사용한 세포 내 위치 분석을 통해 OsABF3가 핵단백질이라는 것을 확인하였다. Yeast one-hybrid 실험을 통해 OsABF3의 Cterminal 부분이 ABREs에 결합한다는 것과 N-terminal 부분 이 하위 유전자의 transactivation 하는데 필요하다는 것을 알수 있었다. 그리고 T-DNA가 삽입된 OsABF3의 homozygous 돌연변이체가 야생형과 과발현체에 비해 발아와 발아 후 단계 에서 고농도의 ABA에 대한 민감도가 더 감소한 것을 알 수 있었다. 결과적으로 종합해 볼 때 OsABF3는 ABA의 의존적인 경로를 통해 비 생물학적 스트레스에 반응하는 유전자의 발현을 조절하는 기능을 하는 전사 조절자이다. 또한 OsABF3의 transactivation을 측정하는 실험에 있어서 억제 domain이 존 재한다는 결과를 얻었다.

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.

UDP-glucose 4-epimerase (UGE; EC 5.1.3.2) is an enzyme that plays an essential role in the interconverts UDP-D-glucose (UDP-Glc) and UDP-Dgalactose (UDP-Gal). Five members of the Chinese cabbage (Brassica rapa) UDP-glucose 4-epimerase gene family, designated BrUGE1 to BrUGE5, have been cloned and characterized. Quantitative PCR shows that the BrUGE1and BrUGE4 mRNA are most abundant among other BrUGE genes, accounting for more than 55% of total BrUGE transcripts in most of the tissues examined. All genes showed organ specific expression pattern, two of which (BrUGE1 and 4) actively responded after Pectobacterium carotovorum subsp. carotovorum infection, while four genes (BrUGE-1, -3, -4 and -5)were shown to respond considerably against salt, drought and abscisic acid (ABA) treatments. To better understand the function of the UGE gene, we constructed a recombinant pART vector carrying the BrUGE1 gene under the control of the CaMV 35S promoter and nos terminator and transformed using Agrobacterium tumefaciens. We then investigated BrUGE1 overexpressing rice lines at the physiological and molecular levels under biotic and abiotic stress conditions. Bioassay of T3 progeny lines of the transgenic plants in Yoshida solution containing 120 mM Nacl for 2 weeks, confirmed that the BrUGE1 enhances salt tolerance to transgenic rice plants. Also T3 progeny lines of the transgenic plants, when exposed to infection caused by Xanthomonas oryzae pv oryzae, showed tolerance to bacterial blight. These results showed that BrUGE1 can be used as potential genetic resource for engineering Brassica with multiple stress resistance.

Susceptible Vitis vinifera responds to Xylella infection with a massive redirection of gene transcription. This transcriptional response is characterized by increased transcripts for phenlypropanoid and flavonoid biosynthesis, ethylene production, adaptation to oxidative stress, and homologs of pathogenesis related (PR) proteins, and decreased transcripts for genes related to photosynthesis. In addition, the results suggest that susceptible genotypes respond to Xylella infection by induction of limited, but inadequate, defense response. We also compared the transcriptional and physiological response of plants treated by pathogen infection, low or moderate water deficit, or a combination of pathogen infection and water deficit. Although the transcriptional response of plants to Xylella infection was distinct from the response of healthy plants to moderate water stress, we observed synergy between water stress and disease, such that water stressed plants exhibit a stronger transcriptional response to the pathogen. This interaction was mirrored at the physiological level for aspects of water relations and photosynthesis, and in terms of the severity of disease symptoms and pathogen colonization, providing a molecular correlation of the classical concept with the disease triangle.

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.

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.

We investigated Arctic plants to determine if they have a specific mechanism enabling them to adapt to extreme environments because they are subject to such conditions throughout their life cycles. Among the cell defense systems of the Arctic mouse-ear chickweed Cerastium arcticum, we identified a stress-responsive dehydrin gene CaDHN that belongs to the SK5 subclass and contains conserved regions with 1 S-segment at the N-terminus and 5 K-segments from the N-terminus to the C-terminus. To investigate the molecular properties of CaDHN, yeast were transformed with CaDHN. CaDHN-expressing transgenic yeast (TG) cells recovered more rapidly from challenge with exogenous stimuli, including oxidants (hydrogen peroxide, menadione, and tert-butyl hydroperoxide), high salinity, freezing and thawing, and metal (Zn2+), than wild-type (WT) cells. TG cells were sensitive to copper, cobalt, and sodium dodecyl sulfate. In addition, the cell survival of TG cells was higher than that of WT cells when cells at the mid-log and stationary stages were exposed to increased ethanol concentrations. There was a significant difference in cultures that have an ethanol content >16%. During glucose-based batch fermentation at generally used (30℃) and low (18℃) temperatures, TG cells produced a higher alcohol concentration through improved cell survival. Specifically, the final alcohol concentrations were 13.3% and 13.2% in TG cells during fermentation at 30℃ and 18℃, respectively, whereas they were 10.2% and 9.4%, respectively, in WT cells under the same fermentation conditions. An in vitro assay revealed that purified CaDHN acted as a reactive oxygen species (ROS)-scavenger by neutralizing H2O2 and a chaperone by preventing high temperature-mediated catalase inactivation. Taken together, our results show that CaDHN expression in transgenic yeast confers tolerance to various abiotic stresses by improving redox homeostasis and enhances fermentation capacity, especially at low temperatures (18℃).

We investigated whether sound could alter gene expression in plants. Using a sound-treated subtractive library, a set of sound-responsive genes in plants was demonstrated through mRNA expression analyses. Of them, the rbcS and ald genes, which are light responsive, up-regulated their expression with sound treatment in both light and in dark conditions. This suggested that sound could be used as a gene regulator instead of light. When we analyzed ald gene expression using various single wavelengths, a significant increase in mRNA levels was found at 125 or 250 Hz but decreased at 50 Hz, indicating that the gene responded to sound in a wavelength-specific manner. To determine whether the ald promoter respond to sound, we generated transgenic rice plants harboring the chimeric gene consisting of a 1,506-bp promoter fragment of the ald gene fused to Escherichia coli GUS reporter gene. Analyses of mRNA expressison level of three independent transgenic lines sound-treated with 50 or 250 Hz for 4 h showed that the Gus gene expression in all three transgenic lines was up regulated by 250 Hz, but down regulated by 50 Hz. These results correlated with sound responsive mRNA expression pattern observed for the ald gene in rice plants, indicating that the 1,506-bp ald promoter confers sound-responsiveness on a reporter gene in transgenic rice plants. We also investigated whether sound waves could improve salt tolerance in rice seedling. The rice seedlings were sound treated with 800 Hz for 1hr, and then treated with 0, 75, 150, and 225mM NaCl for 3 days to observe changes in physiological and morphological aspects. Sound treatment seedlings resulted in enhanced salt stress tolerance, mainly demonstrated by the sound treated seedlings exhibiting of increased root relative water contents (RWC), root length and weight, photochemical efficiency (ratio of variable to maximum fluorescence, Fv/Fm), and germination rate under salt stress condition. This demonstrates that a specific sound wave might be used, not only to alter gene expression in plant, but also to improve salt stress tolerance.

Soybean is an important crop with useful traits such as the high seed protein and oil contents. Soybean reproduction is sensitive to temperature over 35℃. To obtain database of gene expression profiles, we used soybean cultivars, sensitive and tolerant. RNA sequencing was performed to find differentially expressed genes in two Korean soybean cultivars under heat stress condition. The transcriptomic changes in each cultivar under heat stress. We found 2727 common transcripts in two soybean cultivars under heat stress, and selected 20 transcripts to heat stress response genes. The 20 selected genes were analysed using BLAST2GO and PLANEX. The genes were major factor in co-expression networks. It appears that these 20 genes were mainly attributable to heat stress.

The molecular responses to various abiotic stresses were investigated by the approaches with transcriptomic analysis based on an ACP system. Here we identified differentially expressed genes under abiotic stresses in alfalfa seedlings and they were mostly unknown genes and a few common stress-related genes. Among them, mitochondrial small HSP23 was responded by the diverse stress treatment such as heat, salt, As stresses and thus it could be a strong candidate that may confer the abiotic stress tolerance to plants. When expressed in bacteria, recombinant MsHSP23 conferred tolerance to salinity and arsenic stress. Furthermore, MsHSP23 was cloned in a plant expressing vector and transformed into tobacco, a eukaryotic model organism. The transgenic plants exhibited enhanced tolerance to salinity and arsenic stress under ex vitro conditions. In comparison to wild type plants, the transgenic plants exhibited significantly lower electrolyte leakage. Moreover, the transgenic plants had superior germination rates when placed on medium containing arsenic. Taken together, these overexpression results imply that MsHSP23 plays an important role in salinity and arsenic stress tolerance in transgenic tobacco. The results of the present study show that overexpression of alfalfa mitochondrial MsHSP23 in both eukaryotic and prokaryotic model systems confers enhanced tolerance to salt and arsenic stress. This indicates that MsHSP23 could be used potentially for the development of stress tolerant transgenic crops, such as forages.

Environmentally inflicted stress (abiotic stress) such as high drought stress could be limiting the plant productivity. The mechanism of drought stress signaling in plant related with anti-apoptosis has not yet been full described. Understanding drought stress signaling is key to producing drought-tolerant plant. In this study we recently have identified Oryza sativa genes related abiotic stress water deficit. Abiotic stress related genes were screened from Oryza sativa cDNA library and identified gene by yeast functional screening. The yeast expression showed that they east cell grow well on SD-galactose-Leu-Ura-. The screening of over than 7000 clones from Oryza sativa cDNA libraries has been identified. 28 clones that survived following BAX-expression on inducible galactose medium. R12H780 clones confirmed protein prediction like putative senescence-associated-protein. This gene contains an open reading frame (ORF) of 108 amino acids. Transcription of R12H780 was induced in response to drought stresses, RT-PCR analysis showed transcript level in plant strongly detected in earliest time of drought stress treatment. Yeast transformed with R12H780 gene displayed markedly improved tolerance to PEG treatment, and high salinity in comparison to the control yeast (vector only). The results indicate R12H780 expression represents a new type of drought stress related gene with anti-apoptotic in Oryza sativa and endows tolerance to several types abiotic stress.

To characterize CBF/DREB1-homologue in rice, nine OsDREB1 genes have been identified and characterized in this lab. Among these, it was shown that OsDREB1D was induced by drought and slightly by cold stress. We found that OsDREB1A, -1D, and -1E could up-regulate OsDhn1:LUC construct in transactivation assay using rice protoplasts. Transgenic rice plants overexpressing OsDREB1D under the maize ubiquitin promoter (Ubi:OsDREB1D) revealed an enhanced stress tolerance to drought. We also generated transgenic rice of OsDREB1D under OsPOX1 promoter (OsPOX1:OsDREB1D), which is cold stress inducible preferentially in the reproductive organs of rice. We are currently examining the mechanism of the enhanced tolerance of the transgenic plants to drought stress using both molecular physiological and biochemical techniques.