• Korean Journal of Agricultural Science
• /
• v.38 no.2
• /
• pp.199-204
• /
• 2011

This study was conducted to map quantitative trait loci (QTLs) related to drought stress tolerance. An introgression line population derived from a cross, "Ilpum" / "Moroberekan" was used in this study. $F_1$ plants were backcrossed three times to Ilpum to produce $BC_3F_1$ plants. These plants were advanced by selfing for four generation and a total of 117 $BC_3F_5$ introgression lines were developed. These lines were evaluated for percent seed set and spikelets per panicle under the control (field) and drought condition. To identify QTLs related to drought tolerance, 134 SSR markers showing polymorph isms between the parents were genotyped for the 117 $BC_3F_5$ lines. A total of 6 QTLs associated with drought stress were detected on chromosomes 1, 3, 4, 7 and 10. These include two QTLs for phenotypic acceptability, two QTLs for percent seed set ($R^2$ = 19.0 - 20.9%), and two QTLs for spikelets per panicle ($R^2$ = 22.3 - 23.10%). The Moroberekan alleles at three loci contributed the positive effect for drought tolerance. The SSR markers linked to drought stress tolerance can not only facilitate the selection of valuable genes from Moroberekan, but also allow identification of lines with drought tolerance.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.4
• /
• pp.306-313
• /
• 2011

The damage tolerance analysis is required to guarantee the structural safety and the reliability for aircraft components. The damage tolerance method, which evaluate the life considering the initial crack, considers a fatigue design model of the aircraft main structure. The fatigue crack growth life should be calculated in damage tolerance analysis and the inspection time to define the replacement cycle. In this paper, the damage tolerance analysis is performed for a turbine wheel which has complex geometry. The equation of the stress intensity factor for complex geometry is hard to know, so that they are usually processed by finite element analysis which takes long time. To solve this problem, the stress intensity factors at specified crack are obtained by the FEA and the crack growth life is evaluated using the surrogate model which is generated by the regression analysis of the FEA data. From the results, the efficiency of the crack growth life calculation and the damage tolerance analysis could be increased by taking the surrogate model.

• Asian-Australasian Journal of Animal Sciences
• /
• v.32 no.3
• /
• pp.334-340
• /
• 2019

Objective: The objective of this study was to investigate the genetic components of daily milk yield and to re-rank bulls in South Korea by estimated breeding value (EBV) under heat stress using the temperature-humidity index (THI). Methods: This study was conducted using 125,312 monthly test-day records, collected from January 2000 to February 2017 for 19,889 Holstein cows from 647 farms in South Korea. Milk production data were collected from two agencies, the Dairy Cattle Genetic Improvement Center and the Korea Animal Improvement Association, and meteorological data were obtained from 41 regional weather stations using the Automated Surface Observing System (ASOS) installed throughout South Korea. A random regression model using the THI was applied to estimate genetic parameters of heat tolerance based on the test-day records. The model included herd-year-season, calving age, and days-in-milk as fixed effects, as well as heat tolerance as an additive genetic effect, permanent environmental effect, and direct additive and permanent environmental effect. Results: Below the THI threshold (${\leq}72$; no heat stress), the variance in heat tolerance was zero. However, the heat tolerance variance began to increase as THI exceeded the threshold. The covariance between the genetic additive effect and the heat tolerance effect was -0.33. Heritability estimates of milk yield ranged from 0.111 to 0.176 (average: 0.128). Heritability decreased slightly as THI increased, and began to increase at a THI of 79. The predicted bull EBV ranking varied with THI. Conclusion: We conclude that genetic evaluation using the THI function could be useful for selecting bulls for heat tolerance in South Korea.

• The Plant Pathology Journal
• /
• v.36 no.1
• /
• pp.1-10
• /
• 2020

Since salicylic acid (SA) was discovered as an elicitor of tobacco plants inducing the resistance against Tobacco mosaic virus (TMV) in 1979, increasing reports suggest that SA indeed is a key plant hormone regulating plant immunity. In addition, recent studies indicate that SA can regulate many different responses, such as tolerance to abiotic stress, plant growth and development, and soil microbiome. In this review, we focused on the recent findings on SA's effects on resistance to biotic stresses in different plant-pathogen systems, tolerance to different abiotic stresses in different plants, plant growth and development, and soil microbiome. This allows us to discuss about the safe and practical use of SA as a plant defense activator and growth regulator. Crosstalk of SA with different plant hormones, such as abscisic acid, ethylene, jasmonic acid, and auxin in different stress and developmental conditions were also discussed.

• BMB Reports
• /
• v.46 no.1
• /
• pp.31-36
• /
• 2013

Heat shock proteins play an important role in plant stress tolerance and are mainly regulated by heat shock transcription factors (Hsfs). In this study, we generated transgenic rice over-expressing OsHsfA7 and carried out morphological observation and stress tolerance assays. Transgenic plants exhibited less, shorter lateral roots and root hair. Under salt treatment, over-expressing OsHsfA7 rice showed alleviative appearance of damage symptoms and higher survival rate, leaf electrical conductivity and malondialdehyde content of transgenic plants were lower than those of wild type plants. Meanwhile, transgenic rice seedlings restored normal growth but wild type plants could not be rescued after drought and re-watering treatment. These findings indicate that over-expression of OsHsfA7 gene can increase tolerance to salt and drought stresses in rice seedlings.

• Computational Structural Engineering
• /
• v.11 no.1
• /
• pp.161-170
• /
• 1998

A general formulation of the long cylinder tolerance design for the joint structure is here presented. The aim of this paper is to calculate the tolerance of joint by defining tolerance as a kind of uncertainty and to obtain the robustness of the joint structure. It is formulated on the bases of the minimum sensitivity theorem. The objective function is the tolerance sensitivity for the Von-Mises stress. It also took into full account the stress, displacement and weight constraints. PLBA(Pshenichny-Lim-Belegundu-Arora) algorithm is used to solve the constrained nonlinear optimization problem. The finite element analysis is performed with CST(Constant-Strain-Triangle) axisymmetric element. Sensitivities for design variables are calculated by the direct differentiation method. The numerical result is presented for the cylindrical structure where the joint tolerance is treated as random variables.

• Journal of Radiation Industry
• /
• v.4 no.3
• /
• pp.247-252
• /
• 2010

The present study has been performed to select the osmotic tolerant lines using polyethylene glycol (PEG 6000) through an in vitro and in vivo mutagensis with a gamma-ray. During the screening, we selected three mutant lines that seemed to confer elevated osmotic tolerance in high concentrations of PEG 6000. Fruits of these mutants (Os-HK101, Os-HK102 and Os-HK103) were increased to sugar concentration, L-glutamine acid, vitamin C content and lycopine content than those of the wild type. Also the chlorophyll contents were few decreased more in the three mutant lines than the WT plants. Our results suggest that the Os-HK101 is characterized as osmotic stress tolerance considering the sugar concentration and lycopine content. It is expected that the result of this study can be used for breeding more competitive species with respect to contents in sugar or functional chemicals from the selected osmotic resistant lines.

• The Plant Pathology Journal
• /
• v.32 no.6
• /
• pp.552-562
• /
• 2016

Pathogenesis-related proteins play multiple roles in plant development and biotic and abiotic stress tolerance. Here, we characterize a rice defense related gene named "jasmonic acid inducible pathogenesis-related class 10" (JIOsPR10) to gain an insight into its functional properties. Semi-quantitative RT-PCR analysis showed up-regulation of JIOsPR10 under salt and drought stress conditions. Constitutive over-expression JIOsPR10 in rice promoted shoot and root development in transgenic plants, however, their productivity was unaltered. Further experiments exhibited that the transgenic plants showed reduced susceptibility to rice blast fungus, and enhanced salt and drought stress tolerance as compared to the wild type. A comparative proteomic profiling of wild type and transgenic plants showed that overexpression of JIOsPR10 led to the differential modulation of several proteins mainly related with oxidative stresses, carbohydrate metabolism, and plant defense. Taken together, our findings suggest that JIOsPR10 plays important roles in biotic and abiotic stresses tolerance probably by activation of stress related proteins.

• Journal of Microbiology and Biotechnology
• /
• v.29 no.7
• /
• pp.1124-1136
• /
• 2019

Salinity is one of the major abiotic stresses that cause reduction of plant growth and crop productivity. It has been reported that plant growth-promoting bacteria (PGPB) could confer abiotic stress tolerance to plants. In a previous study, we screened bacterial strains capable of enhancing plant health under abiotic stresses and identified these strains based on 16s rRNA sequencing analysis. In this study, we investigated the effects of two selected strains, Bacillus aryabhattai H19-1 and B. mesonae H20-5, on responses of tomato plants against salinity stress. As a result, they alleviated decrease in plant growth and chlorophyll content; only strain H19-1 increased carotenoid content compared to that in untreated plants under salinity stress. Strains H19-1 and H20-5 significantly decreased electrolyte leakage, whereas they increased $Ca^{2+}$ content compared to that in the untreated control. Our results also indicated that H20-5-treated plants accumulated significantly higher levels of proline, abscisic acid (ABA), and antioxidant enzyme activities compared to untreated and H19-1-treated plants during salinity stress. Moreover, strain H20-5 upregulated 9-cisepoxycarotenoid dioxygenase 1 (NCED1) and abscisic acid-response element-binding proteins 1 (AREB1) genes, otherwise strain H19-1 downregulated AREB1 in tomato plants after the salinity challenge. These findings demonstrated that strains H19-1 and H20-5 induced ABA-independent and -dependent salinity tolerance, respectively, in tomato plants, therefore these strains can be used as effective bio-fertilizers for sustainable agriculture.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.175-175
• /
• 2017

To understand molecular mechanisms underlying adaptation of plant cells to saline stress and stress memory, we developed Arabidopsis callus suspension-cultured cells adapted to high salt. Adapted cells to high salt exhibited enhanced tolerance compared to control cells. Moreover, the salt tolerance of adapted cells was stably maintained even after the stress is relieved, indicating that the acquired salt tolerance of adapted cells was memorized. In order to characterize metabolic responses of plant cells during adaptation to high salt stress as well as stress memory, we compared metabolic profiles of salt-adapted and stress-memorized cells with control cells by using NMR spectroscopy. A principle component analysis showed clear metabolic discrimination among control, salt-adapted and stress-memorized cells. Compared with control cells, metabolites related to shikimate metabolism such as tyrosine, and flavonol glycosides, which are related to protective mechanism of plant against stresses were largely up-regulated in adapted cell lines. Moreover, coniferin, a precursor of lignin, was more abundant in salt-adapted cells than control cells. Cell morphology analysis using transmission electron microscopy indicated that cell wall thickness of salt-adapted cells was significantly induced compared to control cells. Consistently, salt adapted cells contained more lignin in their cell walls compared to control cells. The results provide new insight into mechanisms of plant adaptation to saline stress as well as stress memory in metabolic level.