Drought stress is one of the major stresses affecting growth and productivity in rice. Drought tolerance is a complex trait governed by quantitative trait loci(QTLs) making it difficult to understand mechanisms underlying it. We generated a set of 55 introgression lines via backcrosses using Milyang23, the Korean Tongil-type rice variety as the recurrent parent and Oryza glaberrima (IRGC Acc. No. 103544) as a donor parent. 139 SSR markers were used to genotype 55 introgression lines. The 55 introgression lines with Milyang23 were evaluated for physiological traits such as fresh shoot weight (FSW), fresh root weight (FRW) and dry shoot weight (DSW) under the control and 30% PEG-treated condition. Three lines (IL9, IL12, and IL55) showing significant difference with Milyang23 were selected for further analysis. Genotyping revealed that three lines had four, four and two O. glaberrima homozygous segments, respectively. IL9 performed better than Milyang23 in all traits measured in the 30% PEG-treated condition. IL9 possessed four O. glaberrima introgressions on chromosomes 1, 2, 6 and 7. IL12 performed better than Milyang23 in FSW and FRW and contains four O. glaberrima introgressions on chromosomes 3 and 6. IL55 contains two O. glaberrima introgressions on chromosomes 2 and 6. Three lines shared the O. glaberrima segment delimited by markers RM133-RM225 at chromosomes 6. This region corresponds to the QTL region for drought tolerance reported by other previous studies. Although IL9 and IL12 showed improved drought tolerance at the seedling and vegetative stage, they performed poor under the drought stress at the reproductive stage implying that the level of drought tolerance differs according to the growth stage in rice. IL55 was not significantly different from Milyang 23 in SPP and FER and had significantly higher no. of the total grain than Milyang 23. This result seems to indicate that IL55 will be a good resource for drought tolerance breeding. The population would be useful not only in developing drought tolerant lines in the breeding program but also in fine-mapping the genes/QTLs for drought tolerance.

본 연구에서는 밀양23호의 배경에 O. glaberrima의 특정 염색체단편을 가지는 55 이입계통의 내건성 관련 형질을 조 사하여 변이를 검정하고 내건성이 향상된 4 계통을 선발하였 다. 특히 IL55는 유묘기, 영양생장기 그리고 생식생장기에서 반복친인 밀양23호에 비해 조사된 내건성 형질에서 우수한 특성을 보였으며 내건성 관련 유전자의 분석 및 교배모본으 로 이용될 수 있을 것이다. 이입계통들은 밀양23호의 유전적 배경에 각 계통마다 서로 다른 O. glaberrima 단편이 이입된 계통으로, 이 집단은 O. glaberrima에서 유래된 내재해성 및 작물학적으로 유용한 유전자의 탐색에 효율적인 도구가 될 것이다.

The objective of this study was to evaluate the drought tolerance in maize seedling using leaf rolling. Nineteen maize resources, seven Nested Association Mapping parents lines, six Korean commercial cultivars, and six Southeast Asia commercial cultivars, were used to examine drought tolerance. The leaf rolling scores were measured on each leaf in three stress conditions with moderate drought (10%), severe drought (7%), and extreme drought (5%). Generally leaf rolling score of seedlings increased at the lower soil water potentials (5~7%). As a result, drought-tolerant cultivars showed lower leaf rolling score (below 2.5) than the drought sensitive cultivars (above 3.5). Nine varieties, NK4043, CML322, DK9955, NK4300, Ki11, DK8868, CML228, LVN99, and LVN10, have been selected for tolerance to drought stress. These results suggest that the leaf rolling score in maize seedling has been made available to indirect index for drought tolerance.

The MethioninesulfoxidereductaseB2(MsrB2) gene catalyzes the reduction of free and protein-bound methionine sulfoxide to methionine and is known to provide tolerance to biotic and abiotic environmental stresses. There have yet to be any reports that MsrB2 enhances drought tolerance. Two drought-tolerant transgenic rice lines, L-8 (single copy) and L-23 (two copy), expressing the Capsicum annuum MsrB2 (CaMsrB2) gene were selected for stress tolerance phenotyping under drought stress conditions. CaMsrB2 enhanced relative water content (RWC), maintained substantial quantum yield (Fv/Fm ratio), and subsequently improved photosynthetic pigments. Interestingly, L-23, carrying two-copy T-DNA insertion, showed greater drought tolerance through more effective stomatal regulation, carotenoid concentration, and osmotic potential than the wild type. High-tech infrared technology (FLIR SC620) was used for the selection of stress-tolerant physiotypes. Later, the IR results were correlated with other tested physiological parameters. The IR images, average plant temperature, and physiological parameters of the treated plants were discussed in detail.

We 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. In order to test the sound’s effect on plant and its contribution in drought tolerance, plants were subjected to various sound frequencies for an hrs. After 24-hrs sound treatment, plants were exposed to drought for next five days. During the experiment it was observed that sound initiated physiological changes showing tolerance in plant. Sound frequency with ≥ 0.8 kHz enhanced relative water content, stomatal conductance and quantum yield of PSII (Fv/Fm ratio) in drought stress environment. Hydrogen peroxide (H2O2) production in sound treated plantwasdeclinedcomparedtocontrol. ThermaCAM (Infra-red camera) a software which was used to analyze the plant images temperature showed that sound treated plant and leaf had less temperature (heat) compared to control. The physiological mechanism of sound frequencies induce tolerance in rice plants are discussed.

Drought is a one of the most serious abiotic stresses limiting rice production. However, little progress has been made in the genetic analysis of drought tolerance, because it is a complex trait controlled by a number of genes and affected by various environmental factors. The most efficient method for drought tolerance breeding is using drought tolerance genetic resources. We used a doubled-haploid (DH) population consist of 101 lines derived from a cross the drought tolerant cultivar ‘Samgang’ and the drought sensitive cultivar ‘Nagdong’ for QTL analysis. Drought stress was treated by withholding water for 6 weeks, and then rewatered for 7 days. After rewatering visual phenotype was observed according to the standard evaluation system for rice, IRRI. Drought sensitive parent ‘Nagdong’ was almost died, while tolerant parent ‘Samgang’ showed slightly leaf tip dring phenotype. The qdr11 detected on chromosome 11 with flanking markers RM26755-RM287 and accounted for 19% phenotype variation with a LOD score of 3.7.

The global rice reduction due to drought averages 18 Mt, especially, 23 Mha of rice fields in Asia are drought-prone. However, rice breeding programs focusing on drought resistance have made little progress to date. Because proper screening approaches with large scale were not developed to evaluate the drought tolerant degree. In here, we have developed of leaf water loss rate with plastic ware in dark conditions for large screening. Through this bioassay system, we examined drought phenotype degrees of 650 rice varieties. To validate whether this optimized bioassay system is corelated with drought phenotype, we chose 14 varieties having the lowest or highest of the water loss rate. We observed the visual drought phenotype and agricultural traits in green house and field conditions. Apo and Samgang having the lowest of leaf water loss rate showed drought tolerance phenotype, whereas Yeolbaeg and Milyang254 having the highest of leaf water loss rate showed drought sensitive phenotype. Apo displayed proper root length trait and Samgang showed good root dry trait in the greenhouse conditions. These results suggest that a simple screening procedure with water lose rate of leaves is effective to perform large scale screening for drought phenotype in rice.

The perturbation of the steady state of reactive oxygen species due to biotic and abiotic stresses in a plant could lead to protein denaturation through the modification of amino acid residues, including the oxidation of methionine residues. Methionine sulfoxide reductases (MSRs) catalyze the reduction of methionine sulfoxide back to the methionine residue. To assess the role of this enzyme, we generated transgenic rice using a pepper CaMSRB2 gene under the control of the rice Rab21 promoter with/without a selection marker, the bar gene. A drought resistance test on transgenic plants showed that CaMSRB2 confers drought tolerance to rice, as evidenced by less oxidative stress symptoms and a strengthened PSII quantum yield under stress conditions, and increased survival rate and chlorophyll index after the re-watering. The results from immunoblotting using a methionine sulfoxide antibody and nano-LC-MS/MS spectrometry suggest that porphobilinogen deaminase (PBGD), which is involved in chlorophyll synthesis, is a putative target of CaMSRB2. The oxidized methionine content of PBGD expressed in E. coli increased in the presence of H2O2, and the Met-95 and Met-227 residues of PBGD were reduced by CaMSRB2 in the presence of dithiothreitol. An expression profiling analysis of the overexpression lines also suggested that photosystems are less severely affected by drought stress. Our results indicate that CaMSRB2 might play an important functional role in chloroplasts for conferring drought stress tolerance in rice

UDP-glucose 4-epimerase (UGE) catalyzes the reversible conversion of UDP-glucose to UDP-galactose. To understand the biological function of UGE from Brassica rapa, the gene hereinafter referred to as was cloned and overexpressed into Japonica rice cv. Gopum. Transcriptional profiling showed that the is specific to stem of rice plant. Morphological evaluation of the overexpression lines revealed altered phenotype characters particularly in panicle length, number of productive tillers and filled spikelets which account for an increase in yield. This remarkable agronomic performance was ascribed to higher photosynthetic rate complemented with higher CO2 assimilation. Interestingly, BrUGE1 did not only improve plant fitness under optimal condition but also under water deficit stress. The enhanced drought tolerance may be due to the induction of soluble sugar which may act as osmolyte to compensate dehydration during drought stress.

Drought stress is one of the major stress affecting growth and productivity in rice. Drought tolerance is a complex trait governed by quantitative trait loci (QTLs) making it difficult to understand mechanisms underlying it. We generated a set of 55 introgression lines via a backcrossing using Milyang23, a Korean Tongil-type rice variety as the recurrent parent and O. glaberrima (IRGC Acc. No. 103544), an exotic collection from Mali, West Africa as donor parent. 141 SSR markers were used to genotype 55 introgression lines. The 55 introgression lines with the Milyang23 were evaluated for physiological traits such as Fresh shoot weight (FSW), Fresh root weight (FRW) and Dry shoot weight (DSW) under control and 20% PEG-treated condition. Three lines (IL9, 12, 55) showing significant difference with Milyang23 were selected. The genetic background of the three lines were similar to Milyang23 and it has four, four and two O. glaberrima homozygous segments, respectively. IL9 performed better than Milyang23 in all traits measured in the 20% PEG-treated condition. IL9 possessed four O. glaberrima introgressions on chromosomes 1, 2, 6 and 7. IL12 performed better than Milyang23 in FSW and FRW. IL12 contains four O. glaberrima introgressions on chromosomes 3 and 6. And IL55 contains two O. glaberrima introgressions on chromosomes 2 and 6. O. glaberrima segment delimited by markers OSR19-RM225 at chromosomes 6 was commonly present in these three lines. This region corresponds to the QTL region for drought tolerance reported by other previous studies. A set of introgression lines are being developed containing only few chromosomal segments from O. glaberrima in the Milyang23 background. These would be useful not only in developing drought tolerant lines in the breeding program but also in fine-mapping the genes/QTLs for drought resistance.

The global population increase causes various problems as food and energy shortage and environmental change. As for food problem, innovative agricultural system is required to double food production for 10 billion people in the mid of this century. We introduced the genome or chromosomes of related wild species to the common wheat by interspecific crosses and evaluated their characters. Some alien chromosome addition wheat lines showed better bread-making quality, kernel mineral contents, or phosphorus-use efficiency. The lines with a chromosome of Leymus were found to secrete a substance to inhibit nitrification, which may increase nitrogen-use efficiency. In addition, we produced multiple synthetic derivative (MSD) populations in the genetic background of several practical cultivars. The morphology of each plant in the population was similar to that of the common wheat variety and relatively regular with each other, which enabled to find QTLs to elucidate tolerance of abiotic stresses. We are cultivating these lines in the North African countries and evaluating.

Plant growth under water-deficit conditions adversely affects many key processes. Efforts to understand drought stress-related defense mechanisms have revealed a host of plant genes using molecular approaches in rice. Here, we report the novel finding that OsCTR1 E3 ligase regulates both chloroplast-localized chloroplast protein 12 (OsCP12) and ribosomal protein 1 (OsRP1) in protein levels and subcellular localization. The results of a yeast-two hybrid assay, bimolecular fluorescence complementation assay, ubiquitination assay, subcellular localization, and a protein degradation assay support the hypothesis that OsCTR1 functions in trafficking inhibition and proteolysis of OsCP12 and OsRP1 via the ubiquitin 26S proteasome pathway. Heterogeneous overexpression of OsCTR1 in Arabidopsis showed ABA-hypersensitive phenotype in seed germination, seedling growth, and stomatal closure. The transgenic plants also exhibited improvement of water-deficit tolerance with an accumulation of hydrogen peroxide production. These results demonstrate that the OsCTR1 E3 ligase might positively regulate the cellular functions of OsCP12 and RP1 related to photosynthesis under drought stress conditions in rice.

Low temperature is a major factor restrict to growth and limiting productivity of rice crops. We used a cDNA microarray approach to monitor the expression profile of rice (Oryza sativa) under chilling stress and identified 20 chilling inducible genes in previously study. Ten such genes encoding bHLH, metal transporter and, zinc finger protein with unknown functions showed a significant change in expression under various abiotic stresses. Among them, OsCHI1 (Os07g15460), OsCHI2 (Os02g43660), and OsCHI3 (Os01g61160), were selected for further study. They have structural features such as metal-binding signature sequences in their protein sequences, and OsCHI genes were expressed in root of rice seedling and induced in chilling and salt or drought. Expression of OsCHI1, OsCHI3 and OsCHI2 were targeted to membrane and ER when transiently expressed in tobacco cell, respectively. The Arabidopsis (Arabidopsis thaliana) transgenic plants overexpressing showed increased tolerance to salt and drought stress in the seed germination and root elongation than that of wild type. This comprehensive study provides insight into the biological function of OsCHIs, which may be useful in understanding how rice plants adapt to unfavorable environmental conditions.

This study was conducted to provide basic data for high-throughput screening (HTS) system construction based on phenomics. Rice (Oryza sativa cv. Chucheongbyeo) seedlings in vegetative growth stage were grown in the glass house and treated with 0, 3.75, 7.5, 15, and 30% (w/v) of polyethylene glycol (PEG) to give osmotic stress. Three days after PEG treatment, hyper-spectral reflectance images were obtained and analyzed after removing background image in several steps. The reflectance of rice seedlings treated with 15 and 30% of PEG solutions were significantly different at 680 nm, where differences in the chlorophyll reflectance spectrum and visual symptoms were not observed. These results thus indicate that hyper-spectral reflectance observed at 680 nm can be used to screen drought tolerant rice lines. A HTS system equipped with this hyper-spectral reflectance system may play an important role of future rice breeding program.

This study was conducted to figure out the differences in physiological responses, e.g. growth, photosynthetic activity and water potential, and photoinhibition tolerance in photosystem between superior and inferior families of Pinus densiflora under drought condition. Superior which is KW85 and inferior which is KW40 families were selected using progeny test results of height growth. In 2007, seeds were collected from seed orchard. In 2008, seedlings were produced and cultivated, and from April 2009 drought treatment was started with shading treatment and plants were harvested in Sept. 2009. There was no significant difference in height growth between families. In case of leaf water potential, KW85 showed higher water potential under drought condition. But there was no significant difference in drought with shading treatment. There was no difference in photosynthetic rate but stomatal conductance and transpiration rate of KW85 showed lower value than KW40. So water use efficiency of KW85 showed higher value in every treatment. Non-photochemical quenching of KW40 showed higher value in drought treatment, but there was no significant difference in control and drought with shading treatment. Xanthophyll cycle pool size of KW85 showed higher value in drought treatment, but in drought with shading treatment KW40 showed higher value. Selected superior family showed higher drought tolerance according to water use efficiency, and it also has effective non-photochemical quenching ability. In contrast inferior family respond more sensitively in photoinhibition under drought condition.

Tocopherols (α-, β-, γ- and δ-tocopherols) represent a group of lipophilic antioxidants which are synthesized only by photosynthetic organisms. It is widely believed that protection of pigments and proteins of photosynthetic system and polyunsaturated fatty acids from oxidative damage caused by reactive oxygen species (ROS) is the main function of tocopherols. In the present study, NtTC, which encodes a tobacco tocopherol cyclase ortholog, was cloned and characterized. Compared with control plants, NtTC transgenic rice showed higher tolerance to drought stress, and total tocopherol content increased by 52 % in leaf. Additionally, total antioxitant activity of NtTC transgenic lines was increased significantly by 19%. These results demonstrate that over-expressing NtTC could improve the tolerance to abiotic stress in rice, and tocopherols play a crucial role in the protection of oxidative stress.

Transgenic cymbidium plants containing drought and salt stresses tolerance genes were produced by using a highly efficient Agrobacterium-mediated transformation system. The gene (AtSZF2) is salt and drought stresses tolerant gene and transferred into cymbidium plants. These transgenic cymbidium plants are investigated for gene introduction by PCR and analyzed by salt and drought stresses to check its gene expression. To investigate the gene expression of AtSZF2, leaves of transgenic cymbidium plants were soaked in salt solution (200 mM NaCl). Also, transgenic cymbidium plants were kept under no watering for 6 weeks to check the expression of drought stress tolerance. As a result, wild type plants showed more damage than transgenic plants under salt treatment. Further, transgenic cymbidium plants retained green color and healthy status, while wild type plants showed no tolerance after 6 weeks of no-watering treatment.

This study was carried out to establish a proper cultivation site and diagnose the drought tolerance of Pleurospermum camtschaticum, Cirsium setidens and Parasenecio firmus leaves by using pressure-volume curves. The result of ψosat and ψotlp were lower in Pleurospermum camtschaticum leaves. On the other hand, it appeared that Emax of Pleurospermum camtschaticum was approximately six times higher than that of Parasenecio firmus. The values of RWCtlp is all above 88% showing that the function of osmoregulation is somewhat better, and Vo/DW, Vt/DW, Ns/DW of Pleurospermum camtschaticum leaves were approximately 2~4 times Lower than other ones. Thus, responses to water relations of Pleurospermum camtschaticum, Cirsium setidens and Parasenecio firmus such as ψosat, ψotlp, Emax, ψP,max, RWCtlp were shown that the Pleurospermum camtschaticum leave was higher drought tolerance than Cirsium setidens and Parasenecio firmus leaves.