• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.292-292
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• 2022

Since 1992, the Rural Development Administration (RDA), Republic of Korea in collaboration with International Rice Research Institute (IRRI) has developed 6 japonica rice varieties(MS11, Japonica 1, 2, 6, 7 and Cordillera 4) that are adaptable to tropical regions. However, these varieties show moderate resistance or susceptibility to certain biotic and abiotic stress. The development of varieties with more stable forms of resistance is highly desirable, and this could be possibly achieved through rapid introgression of known biotic and abiotic resistant genes. In this study, we analyzed the allele types of major biotic stress resistant genes including Xa5, Xa13, Xa21 and Xa25 for bacterial leaf blight, Pi5, Pi40, Pish and Pita2 for blast, tsv1 for rice tungro spherical virus, and Bph6, Bph9, Bph17, Bph18 and Bph32 for brown planthopper by using gene-specific molecular markers. In addition, seed quality related genes Sdr4 for preharvest sprouting and qLG-9 for seed longevity were also analyzed. The results revealed that2h5 and Xa25 resistance alleles showed in all varieties while Pi5 resistance allele showed only in MS11. The Pish resistance allele were present in five varieties except for Japonica 1. Meanwhile, for the rest of the genes, no presence of resistance alleles found in six varieties. In conclusions, most of tropical japonica varieties are lack of the major biotic stress resistant genes and seed quality genes (Sdr4 and qLG-9). Moreover, the results indicated that rapid deployment of a few major genes in the current tropical japonica rice varieties is urgent to increase durability and spectrum of biotic stress resistance and also seed dormancy/longevity which are essential traits for tropical environments.

• Journal of Plant Biotechnology
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• v.43 no.3
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• pp.317-331
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• 2016

Development of disease resistant plant is one of the important objectives in rice breeding programs because biotic stresses can adversely affect rice growth and yield losses. This study was conducted to identify lines with multiple-resistance genes to biotic stress among 173 hybrid rice breeding lines and germplasms using DNA-based markers. Our results showed that one hybrid rice line [IR98161-2-1-1-k1-3 (IR86409-3-1-1-1-1-1/IRBB66)] possessed 5 bacterial blight resistance genes (Xa4, xa5, Xa7, Xa13 and Xa21) while two hybrid rice lines [IR98161-2-1-1-k1-2 (IR86409-3-1-1-1-1-1/IRBB66) and 7292s (IR75589-31-27-8-33S(S1)/IR102758B)] possessed 3 bacterial blight resistance genes (Xa4, Xa7 and Xa21, and Xa3, Xa4 and xa5). Molecular survey on rice blast disease revealed that most of these lines had two different resistant genes. Only 11 lines possessed Pib, Pi-5, and Pi-ta. In addition, we further surveyed the distribution of insect resistant genes, such as Bph1, Bph18(t), and Wbph. Three hybrid breeding lines [IR98161-2-1-1-k1-3 (IR86409-3-1-1-1-1-1/IRBB66), IR98161-2-1-1-k1-2 (IR86409-3-1-1-1-1-1/IRBB66), and 7292s (IR75589-31-27-8-33S(S1) /IR102758B)] contained all three resistance genes. Finally, we obtained four hybrid rice breeding lines and germplasms [IR98161-2-1-1-k1-2 (IR86409-3-1-1-1-1-1/IRBB66), Damm-Noeub Khmau, 7290s, and 7292s (IR75589-31-27-8-33S(S1)/IR102758B)] possessing six-gene combination. They are expected to provide higher level of multiple resistance to biotic stress. This study is important for genotyping hybrid rice with resistance to diverse diseases and pests. Results obtained in this study suggest that identification of pyramided resistance genes is very important for screening hybrid rice breeding lines and germplasms accurately for disease and pest resistance. We will expand their cultivation safely through bioassays against diseases, pests, and disaster in its main export countries.

• Journal of Microbiology and Biotechnology
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• v.33 no.9
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• pp.1119-1129
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• 2023

Seeds are colonized by diverse microorganisms that can improve the growth and stress resistance of host plants. Although understanding the mechanisms of plant endophyte-host plant interactions is increasing, much of this knowledge does not come from seed endophytes, particularly under environmental stress that the plant host grows to face, including biotic (e.g., pathogens, herbivores and insects) and abiotic factors (e.g., drought, heavy metals and salt). In this article, we first provided a framework for the assembly and function of seed endophytes and discussed the sources and assembly process of seed endophytes. Following that, we reviewed the impact of environmental factors on the assembly of seed endophytes. Lastly, we explored recent advances in the growth promotion and stress resistance enhancement of plants, functioning by seed endophytes under various biotic and abiotic stressors.

• Journal of Ecology and Environment
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• v.44 no.4
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• pp.256-263
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• 2020

Background: Ambrosia trifida is a highly invasive annual plant, but effective control methods have not been proposed. Among various eradication methods, cutting is a simple measure to control invasive plants, and sowing seeds of native plants may effectively increase biotic resistance to invasion. In this study, we conducted a field experiment with two treatments: cutting and sowing seeds of six native or naturalized plants. Results: We found a significantly lower A. trifida abundance after cutting than in the control (77% decrease). Sowing seeds of native species did not provide any additional benefit for the control of A. trifida, but increased the importance values and diversity of other native vegetation. The abundance of A. trifida was negatively correlated with that of other plant taxa based on plant cover, biomass, and density. However, biotic resistance of sown plants was not effective to control invasion because A. trifida was so competitive. Conclusions: We concluded that cutting is an effective measure to control Ambrosia trifida while sowing seeds of native plants can increase native plant diversity.

• Horticultural Science & Technology
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• v.35 no.4
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• pp.499-509
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• 2017

Recently, there has been increased attention to the development of new plant cultivars with enhanced resistance to biotic and abiotic stress. To develop ginseng cultivars with such traits, systematic breeding programs and comprehensive field studies are prerequisites. In this study, we applied a pure-line selection method to identify a ginseng cultivar with enhanced stress resistance. Phenotypic and agronomic characteristics, seed yield, and physiological responses to biotic and abiotic stresses were investigated according to the guidelines of the International Union for the Protection of New Varieties of Plants (UPOV). In the newly developed 'Kowon' cultivar, the time of emergence, flowering, and berry maturity were intermediate between those of the controls, 'Yunpoong' and 'Chunpoong'. The stem length of 'Kowon' was intermediate, whereas the root length was shorter and the main root diameter was greater than those of 'Chunpoong'. In local adaptability tests conducted in three regions, the yield of 'Kowon' was $666kg{\cdot}10a^{-1}$; 27% and 4% higher than that of 'Chunpoong' and 'Yunpoong'. Diseases such as Alternaria blight, Phytophthora blight, mulberry mealybug, and nematode infestation did not occur in 'Kowon'; and it also exhibited moderate resistance to damping-off and anthracnose. In these cases, yellow spots occurred on aerial parts and the rusty skin of the root, and it exhibited moderate resistance at high temperatures. Our study demonstrates that 'Kowon', which has a high root weight and enhanced biotic/abiotic stress resistance, is a superior cultivar that could increase farmers' income.

• Journal of Plant Biotechnology
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• v.40 no.1
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• pp.49-54
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• 2013

C3HC4-type RING zinc finger proteins essential in the regulation of plant processes, including responses to abiotic stresses. We previously isolated and examined the C3HC4-type RING zinc finger protein (BrRZFP1) from Brassica rapa under abiotic stresses. To elucidate the role of the BrRZFP1 transcription factor in gene regulation, we transformed tobacco plants with the BrRZFP1 gene. Plants were regenerated from 82 independently transformed callus lines of tobacco and analysed for transgene expression. Transgene integration and expression was confirmed by Southern and RT-PCR analyses, respectively. T2 plants displayed more tolerance to the bacterial pathogens Pectobacterium carotovorum and Ralstonia solanacearum, and the tolerance levels were correlated with BrRZFP1 expression levels. These results suggest that the transcription factor BrRZFP1 is an important determinant of stress response in plants and its overexpression in plants could increase biotic stress resistance.

• Research in Plant Disease
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• v.23 no.2
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• pp.99-113
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• 2017

Recently, global warming and drastic climate change are the greatest threat to the world. The climate change can affect plant productivity by reducing plant adaptation to diverse environments including frequent high temperature; worsen drought condition and increased pathogen transmission and infection. Plants have to survive in this condition with a variety of biotic (pathogen/pest attack) and abiotic stress (salt, high/low temperature, drought). Plants can interact with beneficial microbes including plant growth-promoting rhizobacteria, which help plant mitigate biotic and abiotic stress. This overview presents that rhizobacteria plays an important role in induced systemic resistance (ISR) to biotic stress or induced systemic tolerance (IST) to abiotic stress condition; bacterial determinants related to ISR and/or IST. In addition, we describe effects of rhizobacteria on defense/tolerance related signal pathway in plants. We also review recent information including plant resistance or tolerance against multiple stresses ($biotic{\times}abiotic$). We desire that this review contribute to expand understanding and knowledge on the microbial application in a constantly varying agroecosystem, and suggest beneficial microbes as one of alternative environment-friendly application to alleviate multiple stresses.

• BMB Reports
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• v.41 no.5
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• pp.376-381
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• 2008

The discovery of RNA silencing inhibition by virus encoded suppressors or low temperature leads to concerns about the stability of transgenic resistance. RNA-dependent RNA polymerase (RdRp) has been previously characterized to be essential for transgene-mediated RNA silencing. Here we showed that low temperature led to the inhibition of RNA silencing, the loss of viral resistance and the reduced expression of host RdRp homolog (NtRdRP1) in transgenic T4 progeny with untranslatable potato virus Y coat protein (PVY-CP) gene. Moreover, RNA silencing and the associated resistance were differently inhibited by potato virus X (PVX) and tobacco mosaic virus (TMV) infections. The increased expression of NtRdRP1 in both PVX and TMV infected plants indicated its general role in response to viral pathogens. Collectively, we propose that biotic and abiotic stress factors affect RNA silencing-mediated resistance in transgenic tobacco plants and that their effects target different steps of RNA silencing.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.228-228
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• 2005

• The Plant Pathology Journal
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• v.28 no.1
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• pp.107-113
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• 2012

Trichomes are specialized epidermal structure having the functions of physical and chemical block against biotic and abiotic stresses. Several studies on $Capsicum$ species revealed that virus and herbivore resistance is associated with trichome-formation. However, there is no research on the structural characterization of trichomes developed on the epidermis of $Capsicum$ spp. Thus, this study attempts to charaterize the trichome morphologies in 5 species of $Capsicum$ using a Field Emission Scanning Electron Microscopy (FESEM). Six main trichome types were identified by their morphology under FESEM. Both glandular and non-glandular types of trichomes were developed on the epidermal tissues of $Capsicum$ spp. The glandular trichome were further classified into type I, IV and VII according to their base, stalk length, and stalk. Non-glandular trichomes were also classified into type II, III, and V based on stalk cell number and norphology. Almost all the species in $C.$ $chinense$ and $C.$ $pubescens$ had glandular trichomes. To our knowledge, this is the first study on classification of trichomes in the genus $Capsicum$ and, our results could provide basic informations for understanding the structure and function of trichomes on the epidermal differentiation and association with biotic stress tolerance.