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Author

Hanhong Bae

Bio: Hanhong Bae is an academic researcher from Yeungnam University. The author has contributed to research in topics: Ginseng & Endophyte. The author has an hindex of 39, co-authored 122 publications receiving 5060 citations. Previous affiliations of Hanhong Bae include United States Department of Agriculture & Bhabha Atomic Research Centre.
Topics: Ginseng, Endophyte, Arabidopsis, Biology, Gene


Papers
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Journal ArticleDOI
TL;DR: The physiology and redox biology of both plants and humans are reviewed to improve the understanding of plant antioxidants as therapeutic entities and the applications and limitations of antioxidant activity measurement assays were highlighted to identify the precise path to be followed for future research in the area of plant antioxidant research.
Abstract: Oxidative stress has been identified as the root cause of the development and progression of several diseases. Supplementation of exogenous antioxidants or boosting endogenous antioxidant defenses of the body is a promising way of combating the undesirable effects of reactive oxygen species (ROS) induced oxidative damage. Plants have an innate ability to biosynthesize a wide range of non-enzymatic antioxidants capable of attenuating ROS- induced oxidative damage. Several in vitro methods have been used to screen plants for their antioxidant potential, and in most of these assays they revealed potent antioxidant activity. However, prior to confirming their in vivo therapeutic efficacy, plant antioxidants have to pass through several physiopharmacological processes. Consequently, the findings of in vitro and in vivo antioxidant potential assessment studies are not always the same. Nevertheless, the results of in vitro assays have been irrelevantly extrapolated to the therapeutic application of plant antioxidants without undertaking sufficient in vivo studies. Therefore, we have briefly reviewed the physiology and redox biology of both plants and humans to improve our understanding of plant antioxidants as therapeutic entities. The applications and limitations of antioxidant activity measurement assays were also highlighted to identify the precise path to be followed for future research in the area of plant antioxidants.

714 citations

Journal ArticleDOI
TL;DR: The primary direct effect of DIS 219b colonization was promotion of root growth, regardless of water status, and an increase in water content which it is proposed caused a delay in many aspects of the drought response of cacao.
Abstract: Theobroma cacao (cacao) is cultivated in tropical climates and is exposed to drought stress. The impact of the endophytic fungus Trichoderma hamatum isolate DIS 219b on cacao’s response to drought was studied. Colonization by DIS 219b delayed drought-induced changes in stomatal conductance, net photosynthesis, and green fluorescence emissions. The altered expression of 19 expressed sequence tags (ESTs) (seven in leaves and 17 in roots with some overlap) by drought was detected using quantitative real-time reverse transcription PCR. Roots tended to respond earlier to drought than leaves, with the drought-induced changes in expression of seven ESTs being observed after 7 d of withholding water. Changes in gene expression in leaves were not observed until after 10 d of withholding water. DIS 219b colonization delayed the drought-altered expression of all seven ESTs responsive to drought in leaves by >3 d, but had less influence on the expression pattern of the drought-responsive ESTs in roots. DIS 219b colonization had minimal direct influence on the expression of drought-responsive ESTs in 32-d-old seedlings. By contrast, DIS 219b colonization of 9-d-old seedlings altered expression of drought-responsive ESTs, sometimes in patterns opposite of that observed in response to drought. Drought induced an increase in the concentration of many amino acids in cacao leaves, while DIS 219b colonization caused a decrease in aspartic acid and glutamic acid concentrations and an increase in alanine and g-aminobutyric acid concentrations. With or without exposure to drought conditions, colonization by DIS 219b promoted seedling growth, the most consistent effects being an increase in root fresh weight, root dry weight, and root water content. Colonized seedlings were slower to wilt in response to drought as measured by a decrease in the leaf angle drop. The primary direct effect of DIS 219b colonization was promotion of root growth, regardless of water status, and an increase in water content which it is proposed caused a delay in many aspects of the drought response of cacao.

420 citations

Journal ArticleDOI
11 Jul 2006-Planta
TL;DR: The pattern of altered gene expression suggests a complex system of genetic cross talk occurs between the cacao tree and Trichoderma isolates during the establishment of the endophytic association.
Abstract: Endophytic isolates of Trichoderma species are being considered as biocontrol agents for diseases of Theobroma cacao (cacao) Gene expression was studied during the interaction between cacao seedlings and four endophytic Trichoderma isolates, T ovalisporum-DIS 70a, T hamatum-DIS 219b, T harzianum-DIS 219f, and Trichoderma sp-DIS 172ai Isolates DIS 70a, DIS 219b, and DIS 219f were mycoparasitic on the pathogen Moniliophthora roreri, and DIS 172ai produced metabolites that inhibited growth of M roreri in culture ESTs (116) responsive to endophytic colonization of cacao were identified using differential display and their expression analyzed using macroarrays Nineteen cacao ESTs and 17 Trichoderma ESTs were chosen for real-time quantitative PCR analysis Seven cacao ESTs were induced during colonization by the Trichoderma isolates These included putative genes for ornithine decarboxylase (P1), GST-like proteins (P4), zinc finger protein (P13), wound-induced protein (P26), EF-calcium-binding protein (P29), carbohydrate oxidase (P59), and an unknown protein (U4) Two plant ESTs, extensin-like protein (P12) and major intrinsic protein (P31), were repressed due to colonization The plant gene expression profile was dependent on the Trichoderma isolate colonizing the cacao seedling The fungal ESTs induced in colonized cacao seedlings also varied with the Trichoderma isolate used The most highly induced fungal ESTs were putative glucosyl hydrolase family 2 (F3), glucosyl hydrolase family 7 (F7), serine protease (F11), and alcohol oxidase (F19) The pattern of altered gene expression suggests a complex system of genetic cross talk occurs between the cacao tree and Trichoderma isolates during the establishment of the endophytic association

254 citations

Journal ArticleDOI
TL;DR: Most of the isolates studied were able to establish an endophytic relationship with cacao by colonizing the above ground portions of the cacao seedling, and exploitation of this characteristic could lead to the development of novel biocontrol strategies for control of cacao diseases.

197 citations

Journal ArticleDOI
TL;DR: In this article, six isolates collected in tropical environments were evaluated for biocontrol activity against Phytophthora capsici in hot pepper (Capsicum annuum).
Abstract: Endophytic Trichoderma isolates collected in tropical environments were evaluated for biocontrol activity against Phytophthora capsici in hot pepper (Capsicum annuum). Six isolates were tested for parasitic and antimicrobial activity against P. capsici and for endophytic and induced resistance capabilities in pepper. Isolates DIS 70a, DIS 219b, and DIS 376f were P. capsici parasites, while DIS 70a, DIS 259j, DIS 320c, and DIS 376f metabolites inhibited P. capsici. All six isolates colonized roots but were inefficient stem colonizers. DIS 259j, DIS 320c, and DIS 376f induced defense-related expressed sequence tags (EST) in 32-day-old peppers. DIS 70a, DIS 259j, and DIS 376f delayed disease development. Initial colonization of roots by DIS 259j or DIS 376f induced EST with potential to impact Trichoderma endophytic colonization and disease development, including multiple lipid transferase protein (LTP)-like family members. The timing and intensity of induction varied between isolates. Expression of CaLTP-N, encoding a LTP-like protein in pepper, in N. benthamiana leaves reduced disease development in response to P. nicotianae inoculation, suggesting LTP are functional components of resistance induced by Trichoderma species. Trichoderma isolates were endophytic on pepper roots in which, depending on the isolate, they delayed disease development by P. capsici and induced strong and divergent defense reactions.

188 citations


Cited by
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Journal Article
Fumio Tajima1
30 Oct 1989-Genomics
TL;DR: It is suggested that the natural selection against large insertion/deletion is so weak that a large amount of variation is maintained in a population.

11,521 citations

Journal ArticleDOI
TL;DR: This review addresses the concept of endophytism, considering the latest insights into evolution, plant ecosystem functioning, and multipartite interactions.
Abstract: All plants are inhabited internally by diverse microbial communities comprising bacterial, archaeal, fungal, and protistic taxa. These microorganisms showing endophytic lifestyles play crucial roles in plant development, growth, fitness, and diversification. The increasing awareness of and information on endophytes provide insight into the complexity of the plant microbiome. The nature of plant-endophyte interactions ranges from mutualism to pathogenicity. This depends on a set of abiotic and biotic factors, including the genotypes of plants and microbes, environmental conditions, and the dynamic network of interactions within the plant biome. In this review, we address the concept of endophytism, considering the latest insights into evolution, plant ecosystem functioning, and multipartite interactions.

1,677 citations

01 Jan 2007
TL;DR: The terms "antioxidant", "oxidative stress" and "oxoidative damage" are widely used but rarely defined as discussed by the authors, and a brief review attempts to define them and to examine the ways in which oxidative stress and oxidative damage can affect cell behaviour both in vivo and in cell culture, using cancer as an example.
Abstract: The terms 'antioxidant', 'oxidative stress' and 'oxidative damage' are widely used but rarely defined. This brief review attempts to define them and to examine the ways in which oxidative stress and oxidative damage can affect cell behaviour both in vivo and in cell culture, using cancer as an example.

1,309 citations

Journal ArticleDOI
TL;DR: There is growing scientific evidence supporting the use of biostimulants as agricultural inputs on diverse plant species, such as increased root growth, enhanced nutrient uptake, and stress tolerance.
Abstract: Plant biostimulants are diverse substances and microorganisms used to enhance plant growth. The global market for biostimulants is projected to increase 12 % per year and reach over $2,200 million by 2018. Despite the growing use of biostimulants in agriculture, many in the scientific community consider biostimulants to be lacking peer-reviewed scientific evaluation. This article describes the emerging definitions of biostimulants and reviews the literature on five categories of biostimulants: i. microbial inoculants, ii. humic acids, iii. fulvic acids, iv. protein hydrolysates and amino acids, and v. seaweed extracts. The large number of publications cited for each category of biostimulants demonstrates that there is growing scientific evidence supporting the use of biostimulants as agricultural inputs on diverse plant species. The cited literature also reveals some commonalities in plant responses to different biostimulants, such as increased root growth, enhanced nutrient uptake, and stress tolerance.

1,305 citations

Book ChapterDOI
01 Jan 2009
TL;DR: In this article, the effects of cross-fertilisation and self fertilization on the production of seeds are discussed. But the main difference between cross-and self-flowered plants is the height and weights of the crossed and self-flowering plants.
Abstract: 1. Introductory remarks 2. Convolvulacaea 2. Scrophulariaceae, Gesneriaceae, Labiatae, etc. 4. Cruciferae, Papaveraceae, Resedaceae, etc. 5. Geraniaceae, Leguminosae, Onagraceae, etc. 6. Solanaceae, Primulaceae, Polygoneae, etc. 7. Summary of the heights and weights of the crossed and self-fertilised plants 8. Difference between crossed and self-fertilised plants in constitutional vigour and in other respects 9. The effects of cross-fertilisation and self-fertilisation on the production of seeds 10. Means of fertilisation 11. The habits of insects in relation to the fertilisation of flowers 12. General results Index.

1,224 citations