Choong-Min Ryu | KOREA RESEARCH INSTITUTE OF BIOSCIENCE AND BIOTECHNOLOGY (original) (raw)
Papers by Choong-Min Ryu
Plants require protection against a wide range of attackers such as insects and pathogens. The ad... more Plants require protection against a wide range of attackers such as insects and pathogens. The adequate plant defense responses are regulated via sophisticated signal cascades, which are activated following the perception of specific cues of the attackers. Plants might, however, gain a significant fitness advantage when pre-empting enemy attack before it actually occurs. Monitoring cues from attacked neighbors can permit plants to reach this goal. We have recently found airborne disease resistance against a bacterial pathogen in uninfected lima bean plants when these were located close to conspecific, resistance-expressing neighbors. The emitters could be chemically induced with benzothiadiazole or biologically with an avirulent pathogen. Unexpectedly, receiver plants, although expressing a functioning resistance, did not show reduced growth rates, which represent a common side-effect of directly induced pathogen resistance. Nonanal was identified as an active volatile and, rather t...
Citrinin, amycotoxin fromPenicillium citrinum ,plays a role in inducingmotilityofPaenibacilluspol... more Citrinin, amycotoxin fromPenicillium citrinum ,plays a role in inducingmotilityofPaenibacilluspolymyxa Soo-Young Park, Rumi Kim, Choong-Min Ryu, Soo-Keun Choi, Choong-Hwan Lee, Jong-Guk Kim & Seung-Hwan Park Systems Microbiology Research Center, KRIBB, Daejeon, Korea; Department of Microbiology, College of Nature Science, Kyungpook National University, Daegu, Korea; and Natural Medicines Research Center, KRIBB, Daejeon, Korea
, maximum scaffoldsizeof1,991,923bp)wereobtained.Notonlywerethetwoassem-bly results consistent wi... more , maximum scaffoldsizeof1,991,923bp)wereobtained.Notonlywerethetwoassem-bly results consistent with each other by direct comparison usingMUMmer (6), but they were also the largest aligned blocks be-tweentwo100%identicalresults(593,857bp),suggestingthattheassembled sequences were accurate regardless of the assemblysoftware.AutomaticgenepredictionandfunctionalannotationofCLC assemblies were carried out using the RAST server (2).Among the 3,892 putative protein-coding genes, 47% were as-signed to 446 subsystem categories. Average nucleotide identityanalysis using completely sequenced
Journal of microbiology and biotechnology, 2010
Twenty-nine P. polymyxa strains isolated from rhizospheres of various crops were clustered into f... more Twenty-nine P. polymyxa strains isolated from rhizospheres of various crops were clustered into five genotypic groups on the basis of BOX-PCR analysis. The characteristics of several plant growth-promoting factors among the isolates revealed the distinct attributes in each allocated group. Under gnotobiotic conditions, inoculation of pepper roots with P. polymyxa isolates significantly increased the biomass in 17 of total 29 treated plants with untreated plants. Experiments on induced systemic resistance (ISR) against bacterial spot pathogen Xanthomonas axonopodis pv. vesicatoria in pepper by P. polymyxa strains were conducted and only one isolate (KNUC265) was selected. Further studies into ISR mediation by the KNUC265 strain against the soft-rot pathogen Erwinia carotovora subsp. carotovora in tobacco demonstrated that the tobacco seedlings exposed to either bacterial volatiles or diffusible metabolites exhibited a reduction in disease severity. In conclusion, ISR and plant growth...
International Journal of Molecular Sciences
Plant association with microorganisms elicits dramatic effects on the local phytobiome and often ... more Plant association with microorganisms elicits dramatic effects on the local phytobiome and often causes systemic and transgenerational modulation on plant immunity against insect pests and microbial pathogens. Previously, we introduced the concept of the plant social networking system (pSNS) to highlight the active involvement of plants in the recruitment of potentially beneficial microbiota upon exposure to insects and pathogens. Microbial association stimulates the physiological responses of plants and induces the development of their immune mechanisms while interacting with multiple enemies. Thus, beneficial microbes serve as important mediators of interactions among multiple members of the multitrophic, microscopic and macroscopic communities. In this review, we classify the steps of pSNS such as elicitation, signaling, secreting root exudates, and plant protection; summarize, with evidence, how plants and beneficial microbes communicate with each other; and also discuss how the...
Trends in Plant Science
Bacteria produce a huge diversity of metabolites, many of which mediate ecological relations. Amo... more Bacteria produce a huge diversity of metabolites, many of which mediate ecological relations. Among these, volatile compounds cause broad-range effects at low doses and, therefore, may be exploited for plant defence strategies and agricultural production, but such applications are still in their early development. Here, we review the latest technologies involving the use of bacterial volatile compounds for phytosanitary inspection, biological control, plant growth promotion, and crop quality. We highlight a variety of effects with a potential applicative interest, based on either live biocontrol and/or biostimulant agents, or the isolated metabolites responsible for the interaction with hosts or competitors. Future agricultural technologies may benefit from the development of new analytical tools to understand bacterial interactions with the environment.
The Plant Pathology Journal
Plants and microorganisms (microbes) use information from chemicals such as volatile compounds to... more Plants and microorganisms (microbes) use information from chemicals such as volatile compounds to understand their environments. Proficiency in sensing and responding to these infochemicals increases an organism's ecological competence and ability to survive in competitive environments, particularly with regard to plant-pathogen interactions. Plants and microbes acquired the ability to sense and respond to biogenic volatiles during their evolutionary history. However, these signals can only be interpreted by humans through the use of state-of the-art technologies. Newly-developed tools allow microbe-induced plant volatiles to be detected in a rapid, precise, and non-invasive manner to diagnose plant diseases. Beside disease diagnosis, volatile compounds may also be valuable in improving crop productivity in sustainable agriculture. Bacterial volatile compounds (BVCs) have potential for use as a novel plant growth stimulant or as improver of fertilizer efficiency. BVCs can also elicit plant innate immunity against insect pests and microbial pathogens. Research is needed to expand our knowledge of BVCs and to produce BVC-based formulations that can be used practically in the field. Formulation possibilities include encapsulation and sol-gel matrices, which can be used in attract and kill formulations, chemigation, and seed priming. Exploitation of biogenic volatiles will facilitate the development of smart integrated plant management systems for disease control and productivity improvement.
Plant Signaling & Behavior
ABSTRACT Plant tissues naturally senesce over time. Attempts to improve plant robustness and incr... more ABSTRACT Plant tissues naturally senesce over time. Attempts to improve plant robustness and increase longevity have involved genetic modification, application of synthetic chemicals, and use of beneficial microbes. Recently, culture supernatant from a microalga Chlorella fusca was found to prime innate immunity against Pseudomonas syringae in Arabidopsis thaliana. However, the capacity of Chlorella culture supernatants to prevent or delay aging in higher plants has not been elucidated. In this study, roots of the ornamental flowering plant Erinus alpinus L. were drenched with cell-free supernatants from three Chlorella species. Flower and leaf senescence in E. alpinus was significantly reduced and delayed with all three Chlorella supernatants. Investigations of the mode of action underlying delayed senescence showed that the Chlorella supernatants did not act as a chemical trigger to elicit plant immunity or as a growth-promoting fertilizer in E. alpinus. The mechanisms underlying the anti-aging effects remain undetermined, and several possible hypotheses are discussed. Several Chlorella species are industrially cultivated, and disposal of cell-free supernatant can be economically and environmentally challenging. This study provides a novel method for extending plant lifespan through use of Chlorella supernatant and discusses the potential of using industrial waste supernatants in agriculture and horticulture to reduce reliance on chemical pesticides and genetic modification.
Research in Plant Disease
Worldwide crop loss caused by insect pest and nematode reaches critical level. In Korea, similar ... more Worldwide crop loss caused by insect pest and nematode reaches critical level. In Korea, similar crop loss has been gradually augmented in the field and greenhouse due to continuous crop rotation. The current methods on controlling herbivorous insects and plant parasitic nematodes are mostly depended on agro-chemicals that have resulted additional side-effect including occurrence of resistant insects and nematodes, environmental contamination, and accumulation in human body. To overcome the pitfalls, microbe-based control method have been introduced and applied for several decades. Here, we revised biological control using by the bacteria, fungi, and virus in order to kill insect and nematode and to attenuate its virulence mechanism. The introduced microbes mainly secreted out the hydrolysing enzymes and toxic compounds to target host membrane or cell wall directly. Indirectly, the microbe-triggered plant innate immunity against insects and nematodes was also reported. In conclusion, we provide a new frontier of microbe-based environmentally friendly procedure and effective methods to manage insects and nematodes.
Korean Journal of Occupational and Environmental Medicine
Environmental Microbiology Reports
Since the discovery of the role of microbes in the phytobiome, microbial communities (microbiota)... more Since the discovery of the role of microbes in the phytobiome, microbial communities (microbiota) have been identified and characterized based on host species, development, distribution, and condition. The microbiota in the plant rhizosphere is believed to have been established prior to seed germination and innate immune development. However, the microbiota in seeds has received little attention. Although our knowledge of the distribution of microbiota in plant seeds and rhizosphere is currently limited, the impact of these microbiota is likely to be greater than expected. This minireview suggests a new function of microbial inheritance from the seed to root and from the first generation of plants to the next. Surprisingly, recruitment and accumulation of microbiota by biotic and abiotic stresses affect plant immunity in the next generation through plant-soil feedback and soil memory. To illustrate this process, we propose a new term called 'microbiota-induced soil inheritance (MISI).' A comprehensive understanding of MISI will provide novel insights into plant-microbe interactions and plant immunity inheritance.
Algal Research
Abstract Microalgal interactions with bacteria are ubiquitous, and are crucial for algal survival... more Abstract Microalgal interactions with bacteria are ubiquitous, and are crucial for algal survival. Nevertheless, the detailed mechanisms underpinning the bacterial interactions and their beneficial consequences are unclear. In the current study, we studied the interactions of the model microalga Chlorella vulgaris with a model prokaryote Escherichia coli. We employed a complete set of E. coli K-12 ORF archive (ASKA) library overexpressing a complete set of E. coli K-12 open reading frames to identify the target bacterial genes whose products enhance C. vulgaris growth. During three successive screening rounds, 32 genes were selected whose overexpression resulted in >1.4-fold increase in algal chlorophyll a content. Four genes ribA, ribD, ribE and ssuE that exerted a growth-promoting effect on C. vulgaris were finally identified. These genes were involved in the bacterial riboflavin biosynthesis pathway, which was validated by determining the riboflavin content in the four selected E. coli clones and confirmed by the analysis of the growth-promoting effect of synthetic riboflavin on C. vulgaris. Collectively, these observations revealed a new bacterial determinant involved in microalgae growth promotion. The genome-wide high-throughput screening system provided insight into the long-term adaptation of C. vulgaris to bacterial interactions.
Frontiers in plant science, 2018
The volatile compound 2,3-butanediol, which is produced by certain strains of root-associated bac... more The volatile compound 2,3-butanediol, which is produced by certain strains of root-associated bacteria, consists of three stereoisomers, namely, two enantiomers (2R,3R- and 2S,3S-butanediol) and one meso compound (2R,3S-butanediol). The ability of 2,3-butanediol to induce plant resistance against pathogenic fungi and bacteria has been investigated; however, little is known about its effects on induced resistance against viruses in plants. To investigate the effects of 2,3-butanediol on plant systemic defense against viruses, we evaluated the disease control capacity of each of its three stereoisomers in pepper. Specifically, we investigated the optimal concentration of 2,3-butanediol to use for disease control against and in the greenhouse and examined the effects of drench application of these compounds in the field. In the field trial, treatment with 2R,3R-butanediol and 2R,3S-butanediol significantly reduced the incidence of naturally occurring viruses compared with 2S,3S-butaned...
![Research paper thumbnail of {"__content__"=>"Complete Genome Sequences of CR-Eb1 and sp. Strain CR-Ec1, Isolated from the Larval Gut of the Greater Wax Moth, .", "i"=>[{"__content__"=>"Enterobacter cancerogenus"}, {"__content__"=>"Enterococcus"}, {"__content__"=>"Galleria mellonella"}]}](https://attachments.academia-assets.com/82040350/thumbnails/1.jpg)
](Genome announcements, Jan 15, 2018
CR-Eb1 and sp. CR-Ec1 were isolated from the larval gut of , the greater wax moth. Here, we repor... more CR-Eb1 and sp. CR-Ec1 were isolated from the larval gut of , the greater wax moth. Here, we report the completed and annotated genome sequences of insect gut-dwelling bacteria.
Scientific reports, Jan 27, 2017
Seed priming is to expose seeds to specific compounds to enhance seed germination. Few studies of... more Seed priming is to expose seeds to specific compounds to enhance seed germination. Few studies of plant immune activation through seed priming have been conducted. Here, we introduce an emerging technology that combines seed priming with elicitation of plant immunity using biologically active compounds. This technology is named 'seed defense biopriming' (SDB). We prepared heat-stable metabolites from 1,825 root-associated Bacillus spp. isolated from the rhizosphere in South Korea. These preparations were tested for their ability to induce SDB in cucumber and pepper seeds and trigger plant immunity. SDB with heat-stable metabolites of the selected Bacillus gaemokensis strain PB69 significantly reduced subsequent bacterial diseases under in vitro and field conditions and increased fruit yield. Transcriptional analysis of induced resistance marker genes confirmed the upregulation of salicylic acid, ethylene, and jasmonic acid signaling. Mortality of the insect pest Spodoptera l...
Frontiers in plant science, 2017
Receptor-like kinases are important signaling components that regulate a variety of cellular proc... more Receptor-like kinases are important signaling components that regulate a variety of cellular processes. In this study, an Arabidopsis cDNA microarray analysis led to the identification of the cysteine-rich receptor-like kinase CRK36 responsive to the necrotrophic fungal pathogen, Alternaria brassicicola. To determine the function of CRK36 in plant immunity, T-DNA-insertion knockdown (crk36) and overexpressing (CRK36OE) plants were prepared. CRK36OE plants exhibited increased hypersensitive cell death and ROS burst in response to avirulent pathogens. Treatment with a typical pathogen-associated molecular pattern, flg22, markedly induced pattern-triggered immune responses, notably stomatal defense, in CRK36OE plants. The immune responses were weakened in crk36 plants. Protein-protein interaction assays revealed the in vivo association of CRK36, FLS2, and BIK1. CRK36 enhanced flg22-triggered BIK1 phosphorylation, which showed defects with Cys mutations in the DUF26 motifs of CRK36. Dis...
The Plant Pathology Journal
Previous studies have addressed the management of phyllosphere pathogens by leaf and root-associa... more Previous studies have addressed the management of phyllosphere pathogens by leaf and root-associated microbes. The present study evaluated the effect of the foliar application of three strains of Bacillus spp. on plant growth and fruit quality. The application of a bacilli spore preparation significantly improved leaf growth parameters such as leaf thickness and photosynthesis capacity, indicating that bacilli treatment directly promoted leaf growth. In addition, foliar treatment resulted in an improvement in the key indicators of fruit quality including water, glucose, and sucrose contents. The present results suggest that foliar spraying of beneficial bacilli is a potential treatment of wide application for the improvement of apple quality. Foliar application of bacilli preparation as effective plant growth-promoting rhizobacteria broadens the spectrum of their availability for orchard application.
Research in Plant Disease
Plant have developed sophisticated defence mechanisms against microbial pathogens. The recent acc... more Plant have developed sophisticated defence mechanisms against microbial pathogens. The recent accumulated information allow us to understand the nature of plant immune responses followed by recognition of microbial factors/determinants through cutting-edge genomics and multi-omics techniques. However, the practical approaches to sustain plant health using enhancement of plant immunity is yet to be fully appreciated. Here, we overviewed the general concept and representative examples on the plant immunity. The fungal, bacterial, and viral determinants that was previously reported as the triggers of plant immune responses are introduced and described as the potential protocol of biological control. Specifically, the role of chitin, glucan, lipopolysaccharides/extracellular polysaccharides, microbe/pathogen-associated molecular pattern, antibiotics, mimic-phytohormones, N-acyl homoserine lactone, harpin, vitamins, and volatile organic compounds are considered. We hope that this review stimulates scientific community and farmers to broaden their knowledge on the microbial determinant-based biological control and to apply the technology on the integrated pest management program.
Molecular plant pathology, 2017
The Gac/Rsm network regulates at the transcriptional level many beneficial traits in biocontrol-a... more The Gac/Rsm network regulates at the transcriptional level many beneficial traits in biocontrol-active pseudomonads. In this study, we used Phenotype MicroArrays followed by specific growth studies and mutational analysis to understand how catabolism is regulated by this sensor kinase system in the biocontrol isolate, Pseudomonas chlororaphis O6. Growth of a gacS mutant was decreased significantly compared to that of the wild-type on ornithine and arginine, and the precursor of these amino acids, N-acetyl-l-glutamic acid. The gacS mutant also showed reduced production of polyamines. Expression of the genes encoding arginine decarboxylase (speA) and ornithine decarboxylases (speC) was controlled at the transcriptional level by the GacS sensor of P. chlororaphis O6. Polyamine production was reduced in the speC mutant, and was eliminated in the speAspeC mutant. Addition of exogenous polyamines to the speAspeC mutant restored in vitro growth inhibition of two fungal pathogens as well as...
Nature protocols, 2017
Airborne chemical signals emitted by bacteria influence the behavior of other bacteria and plants... more Airborne chemical signals emitted by bacteria influence the behavior of other bacteria and plants. We present an overview of in vitro methods for evaluating bacterial and plant responses to bacterial volatile compounds (BVCs). Three types of equipment have been used to physically separate the bacterial test strains from either other bacterial strains or plants (in our laboratory we use either Arabidopsis or tobacco plant seedlings): a Petri dish containing two compartments (BI Petri dish); two Petri dishes connected with tubing; and a microtiter-based assay. The optimized procedure for the BI Petri dish system is described in this protocol and can be widely used for elucidation of potential function in interactions between diverse microbes and those plant and chemical volatiles emitted by bacteria that are most likely to mediate bacterial or plant responses to BVCs. We also describe a procedure for metabolome-based BVC profiling via dynamic (i.e., continuous airflow) or static heads...
Plants require protection against a wide range of attackers such as insects and pathogens. The ad... more Plants require protection against a wide range of attackers such as insects and pathogens. The adequate plant defense responses are regulated via sophisticated signal cascades, which are activated following the perception of specific cues of the attackers. Plants might, however, gain a significant fitness advantage when pre-empting enemy attack before it actually occurs. Monitoring cues from attacked neighbors can permit plants to reach this goal. We have recently found airborne disease resistance against a bacterial pathogen in uninfected lima bean plants when these were located close to conspecific, resistance-expressing neighbors. The emitters could be chemically induced with benzothiadiazole or biologically with an avirulent pathogen. Unexpectedly, receiver plants, although expressing a functioning resistance, did not show reduced growth rates, which represent a common side-effect of directly induced pathogen resistance. Nonanal was identified as an active volatile and, rather t...
Citrinin, amycotoxin fromPenicillium citrinum ,plays a role in inducingmotilityofPaenibacilluspol... more Citrinin, amycotoxin fromPenicillium citrinum ,plays a role in inducingmotilityofPaenibacilluspolymyxa Soo-Young Park, Rumi Kim, Choong-Min Ryu, Soo-Keun Choi, Choong-Hwan Lee, Jong-Guk Kim & Seung-Hwan Park Systems Microbiology Research Center, KRIBB, Daejeon, Korea; Department of Microbiology, College of Nature Science, Kyungpook National University, Daegu, Korea; and Natural Medicines Research Center, KRIBB, Daejeon, Korea
, maximum scaffoldsizeof1,991,923bp)wereobtained.Notonlywerethetwoassem-bly results consistent wi... more , maximum scaffoldsizeof1,991,923bp)wereobtained.Notonlywerethetwoassem-bly results consistent with each other by direct comparison usingMUMmer (6), but they were also the largest aligned blocks be-tweentwo100%identicalresults(593,857bp),suggestingthattheassembled sequences were accurate regardless of the assemblysoftware.AutomaticgenepredictionandfunctionalannotationofCLC assemblies were carried out using the RAST server (2).Among the 3,892 putative protein-coding genes, 47% were as-signed to 446 subsystem categories. Average nucleotide identityanalysis using completely sequenced
Journal of microbiology and biotechnology, 2010
Twenty-nine P. polymyxa strains isolated from rhizospheres of various crops were clustered into f... more Twenty-nine P. polymyxa strains isolated from rhizospheres of various crops were clustered into five genotypic groups on the basis of BOX-PCR analysis. The characteristics of several plant growth-promoting factors among the isolates revealed the distinct attributes in each allocated group. Under gnotobiotic conditions, inoculation of pepper roots with P. polymyxa isolates significantly increased the biomass in 17 of total 29 treated plants with untreated plants. Experiments on induced systemic resistance (ISR) against bacterial spot pathogen Xanthomonas axonopodis pv. vesicatoria in pepper by P. polymyxa strains were conducted and only one isolate (KNUC265) was selected. Further studies into ISR mediation by the KNUC265 strain against the soft-rot pathogen Erwinia carotovora subsp. carotovora in tobacco demonstrated that the tobacco seedlings exposed to either bacterial volatiles or diffusible metabolites exhibited a reduction in disease severity. In conclusion, ISR and plant growth...
International Journal of Molecular Sciences
Plant association with microorganisms elicits dramatic effects on the local phytobiome and often ... more Plant association with microorganisms elicits dramatic effects on the local phytobiome and often causes systemic and transgenerational modulation on plant immunity against insect pests and microbial pathogens. Previously, we introduced the concept of the plant social networking system (pSNS) to highlight the active involvement of plants in the recruitment of potentially beneficial microbiota upon exposure to insects and pathogens. Microbial association stimulates the physiological responses of plants and induces the development of their immune mechanisms while interacting with multiple enemies. Thus, beneficial microbes serve as important mediators of interactions among multiple members of the multitrophic, microscopic and macroscopic communities. In this review, we classify the steps of pSNS such as elicitation, signaling, secreting root exudates, and plant protection; summarize, with evidence, how plants and beneficial microbes communicate with each other; and also discuss how the...
Trends in Plant Science
Bacteria produce a huge diversity of metabolites, many of which mediate ecological relations. Amo... more Bacteria produce a huge diversity of metabolites, many of which mediate ecological relations. Among these, volatile compounds cause broad-range effects at low doses and, therefore, may be exploited for plant defence strategies and agricultural production, but such applications are still in their early development. Here, we review the latest technologies involving the use of bacterial volatile compounds for phytosanitary inspection, biological control, plant growth promotion, and crop quality. We highlight a variety of effects with a potential applicative interest, based on either live biocontrol and/or biostimulant agents, or the isolated metabolites responsible for the interaction with hosts or competitors. Future agricultural technologies may benefit from the development of new analytical tools to understand bacterial interactions with the environment.
The Plant Pathology Journal
Plants and microorganisms (microbes) use information from chemicals such as volatile compounds to... more Plants and microorganisms (microbes) use information from chemicals such as volatile compounds to understand their environments. Proficiency in sensing and responding to these infochemicals increases an organism's ecological competence and ability to survive in competitive environments, particularly with regard to plant-pathogen interactions. Plants and microbes acquired the ability to sense and respond to biogenic volatiles during their evolutionary history. However, these signals can only be interpreted by humans through the use of state-of the-art technologies. Newly-developed tools allow microbe-induced plant volatiles to be detected in a rapid, precise, and non-invasive manner to diagnose plant diseases. Beside disease diagnosis, volatile compounds may also be valuable in improving crop productivity in sustainable agriculture. Bacterial volatile compounds (BVCs) have potential for use as a novel plant growth stimulant or as improver of fertilizer efficiency. BVCs can also elicit plant innate immunity against insect pests and microbial pathogens. Research is needed to expand our knowledge of BVCs and to produce BVC-based formulations that can be used practically in the field. Formulation possibilities include encapsulation and sol-gel matrices, which can be used in attract and kill formulations, chemigation, and seed priming. Exploitation of biogenic volatiles will facilitate the development of smart integrated plant management systems for disease control and productivity improvement.
Plant Signaling & Behavior
ABSTRACT Plant tissues naturally senesce over time. Attempts to improve plant robustness and incr... more ABSTRACT Plant tissues naturally senesce over time. Attempts to improve plant robustness and increase longevity have involved genetic modification, application of synthetic chemicals, and use of beneficial microbes. Recently, culture supernatant from a microalga Chlorella fusca was found to prime innate immunity against Pseudomonas syringae in Arabidopsis thaliana. However, the capacity of Chlorella culture supernatants to prevent or delay aging in higher plants has not been elucidated. In this study, roots of the ornamental flowering plant Erinus alpinus L. were drenched with cell-free supernatants from three Chlorella species. Flower and leaf senescence in E. alpinus was significantly reduced and delayed with all three Chlorella supernatants. Investigations of the mode of action underlying delayed senescence showed that the Chlorella supernatants did not act as a chemical trigger to elicit plant immunity or as a growth-promoting fertilizer in E. alpinus. The mechanisms underlying the anti-aging effects remain undetermined, and several possible hypotheses are discussed. Several Chlorella species are industrially cultivated, and disposal of cell-free supernatant can be economically and environmentally challenging. This study provides a novel method for extending plant lifespan through use of Chlorella supernatant and discusses the potential of using industrial waste supernatants in agriculture and horticulture to reduce reliance on chemical pesticides and genetic modification.
Research in Plant Disease
Worldwide crop loss caused by insect pest and nematode reaches critical level. In Korea, similar ... more Worldwide crop loss caused by insect pest and nematode reaches critical level. In Korea, similar crop loss has been gradually augmented in the field and greenhouse due to continuous crop rotation. The current methods on controlling herbivorous insects and plant parasitic nematodes are mostly depended on agro-chemicals that have resulted additional side-effect including occurrence of resistant insects and nematodes, environmental contamination, and accumulation in human body. To overcome the pitfalls, microbe-based control method have been introduced and applied for several decades. Here, we revised biological control using by the bacteria, fungi, and virus in order to kill insect and nematode and to attenuate its virulence mechanism. The introduced microbes mainly secreted out the hydrolysing enzymes and toxic compounds to target host membrane or cell wall directly. Indirectly, the microbe-triggered plant innate immunity against insects and nematodes was also reported. In conclusion, we provide a new frontier of microbe-based environmentally friendly procedure and effective methods to manage insects and nematodes.
Korean Journal of Occupational and Environmental Medicine
Environmental Microbiology Reports
Since the discovery of the role of microbes in the phytobiome, microbial communities (microbiota)... more Since the discovery of the role of microbes in the phytobiome, microbial communities (microbiota) have been identified and characterized based on host species, development, distribution, and condition. The microbiota in the plant rhizosphere is believed to have been established prior to seed germination and innate immune development. However, the microbiota in seeds has received little attention. Although our knowledge of the distribution of microbiota in plant seeds and rhizosphere is currently limited, the impact of these microbiota is likely to be greater than expected. This minireview suggests a new function of microbial inheritance from the seed to root and from the first generation of plants to the next. Surprisingly, recruitment and accumulation of microbiota by biotic and abiotic stresses affect plant immunity in the next generation through plant-soil feedback and soil memory. To illustrate this process, we propose a new term called 'microbiota-induced soil inheritance (MISI).' A comprehensive understanding of MISI will provide novel insights into plant-microbe interactions and plant immunity inheritance.
Algal Research
Abstract Microalgal interactions with bacteria are ubiquitous, and are crucial for algal survival... more Abstract Microalgal interactions with bacteria are ubiquitous, and are crucial for algal survival. Nevertheless, the detailed mechanisms underpinning the bacterial interactions and their beneficial consequences are unclear. In the current study, we studied the interactions of the model microalga Chlorella vulgaris with a model prokaryote Escherichia coli. We employed a complete set of E. coli K-12 ORF archive (ASKA) library overexpressing a complete set of E. coli K-12 open reading frames to identify the target bacterial genes whose products enhance C. vulgaris growth. During three successive screening rounds, 32 genes were selected whose overexpression resulted in >1.4-fold increase in algal chlorophyll a content. Four genes ribA, ribD, ribE and ssuE that exerted a growth-promoting effect on C. vulgaris were finally identified. These genes were involved in the bacterial riboflavin biosynthesis pathway, which was validated by determining the riboflavin content in the four selected E. coli clones and confirmed by the analysis of the growth-promoting effect of synthetic riboflavin on C. vulgaris. Collectively, these observations revealed a new bacterial determinant involved in microalgae growth promotion. The genome-wide high-throughput screening system provided insight into the long-term adaptation of C. vulgaris to bacterial interactions.
Frontiers in plant science, 2018
The volatile compound 2,3-butanediol, which is produced by certain strains of root-associated bac... more The volatile compound 2,3-butanediol, which is produced by certain strains of root-associated bacteria, consists of three stereoisomers, namely, two enantiomers (2R,3R- and 2S,3S-butanediol) and one meso compound (2R,3S-butanediol). The ability of 2,3-butanediol to induce plant resistance against pathogenic fungi and bacteria has been investigated; however, little is known about its effects on induced resistance against viruses in plants. To investigate the effects of 2,3-butanediol on plant systemic defense against viruses, we evaluated the disease control capacity of each of its three stereoisomers in pepper. Specifically, we investigated the optimal concentration of 2,3-butanediol to use for disease control against and in the greenhouse and examined the effects of drench application of these compounds in the field. In the field trial, treatment with 2R,3R-butanediol and 2R,3S-butanediol significantly reduced the incidence of naturally occurring viruses compared with 2S,3S-butaned...
Genome announcements, Jan 15, 2018
CR-Eb1 and sp. CR-Ec1 were isolated from the larval gut of , the greater wax moth. Here, we repor... more CR-Eb1 and sp. CR-Ec1 were isolated from the larval gut of , the greater wax moth. Here, we report the completed and annotated genome sequences of insect gut-dwelling bacteria.
Scientific reports, Jan 27, 2017
Seed priming is to expose seeds to specific compounds to enhance seed germination. Few studies of... more Seed priming is to expose seeds to specific compounds to enhance seed germination. Few studies of plant immune activation through seed priming have been conducted. Here, we introduce an emerging technology that combines seed priming with elicitation of plant immunity using biologically active compounds. This technology is named 'seed defense biopriming' (SDB). We prepared heat-stable metabolites from 1,825 root-associated Bacillus spp. isolated from the rhizosphere in South Korea. These preparations were tested for their ability to induce SDB in cucumber and pepper seeds and trigger plant immunity. SDB with heat-stable metabolites of the selected Bacillus gaemokensis strain PB69 significantly reduced subsequent bacterial diseases under in vitro and field conditions and increased fruit yield. Transcriptional analysis of induced resistance marker genes confirmed the upregulation of salicylic acid, ethylene, and jasmonic acid signaling. Mortality of the insect pest Spodoptera l...
Frontiers in plant science, 2017
Receptor-like kinases are important signaling components that regulate a variety of cellular proc... more Receptor-like kinases are important signaling components that regulate a variety of cellular processes. In this study, an Arabidopsis cDNA microarray analysis led to the identification of the cysteine-rich receptor-like kinase CRK36 responsive to the necrotrophic fungal pathogen, Alternaria brassicicola. To determine the function of CRK36 in plant immunity, T-DNA-insertion knockdown (crk36) and overexpressing (CRK36OE) plants were prepared. CRK36OE plants exhibited increased hypersensitive cell death and ROS burst in response to avirulent pathogens. Treatment with a typical pathogen-associated molecular pattern, flg22, markedly induced pattern-triggered immune responses, notably stomatal defense, in CRK36OE plants. The immune responses were weakened in crk36 plants. Protein-protein interaction assays revealed the in vivo association of CRK36, FLS2, and BIK1. CRK36 enhanced flg22-triggered BIK1 phosphorylation, which showed defects with Cys mutations in the DUF26 motifs of CRK36. Dis...
The Plant Pathology Journal
Previous studies have addressed the management of phyllosphere pathogens by leaf and root-associa... more Previous studies have addressed the management of phyllosphere pathogens by leaf and root-associated microbes. The present study evaluated the effect of the foliar application of three strains of Bacillus spp. on plant growth and fruit quality. The application of a bacilli spore preparation significantly improved leaf growth parameters such as leaf thickness and photosynthesis capacity, indicating that bacilli treatment directly promoted leaf growth. In addition, foliar treatment resulted in an improvement in the key indicators of fruit quality including water, glucose, and sucrose contents. The present results suggest that foliar spraying of beneficial bacilli is a potential treatment of wide application for the improvement of apple quality. Foliar application of bacilli preparation as effective plant growth-promoting rhizobacteria broadens the spectrum of their availability for orchard application.
Research in Plant Disease
Plant have developed sophisticated defence mechanisms against microbial pathogens. The recent acc... more Plant have developed sophisticated defence mechanisms against microbial pathogens. The recent accumulated information allow us to understand the nature of plant immune responses followed by recognition of microbial factors/determinants through cutting-edge genomics and multi-omics techniques. However, the practical approaches to sustain plant health using enhancement of plant immunity is yet to be fully appreciated. Here, we overviewed the general concept and representative examples on the plant immunity. The fungal, bacterial, and viral determinants that was previously reported as the triggers of plant immune responses are introduced and described as the potential protocol of biological control. Specifically, the role of chitin, glucan, lipopolysaccharides/extracellular polysaccharides, microbe/pathogen-associated molecular pattern, antibiotics, mimic-phytohormones, N-acyl homoserine lactone, harpin, vitamins, and volatile organic compounds are considered. We hope that this review stimulates scientific community and farmers to broaden their knowledge on the microbial determinant-based biological control and to apply the technology on the integrated pest management program.
Molecular plant pathology, 2017
The Gac/Rsm network regulates at the transcriptional level many beneficial traits in biocontrol-a... more The Gac/Rsm network regulates at the transcriptional level many beneficial traits in biocontrol-active pseudomonads. In this study, we used Phenotype MicroArrays followed by specific growth studies and mutational analysis to understand how catabolism is regulated by this sensor kinase system in the biocontrol isolate, Pseudomonas chlororaphis O6. Growth of a gacS mutant was decreased significantly compared to that of the wild-type on ornithine and arginine, and the precursor of these amino acids, N-acetyl-l-glutamic acid. The gacS mutant also showed reduced production of polyamines. Expression of the genes encoding arginine decarboxylase (speA) and ornithine decarboxylases (speC) was controlled at the transcriptional level by the GacS sensor of P. chlororaphis O6. Polyamine production was reduced in the speC mutant, and was eliminated in the speAspeC mutant. Addition of exogenous polyamines to the speAspeC mutant restored in vitro growth inhibition of two fungal pathogens as well as...
Nature protocols, 2017
Airborne chemical signals emitted by bacteria influence the behavior of other bacteria and plants... more Airborne chemical signals emitted by bacteria influence the behavior of other bacteria and plants. We present an overview of in vitro methods for evaluating bacterial and plant responses to bacterial volatile compounds (BVCs). Three types of equipment have been used to physically separate the bacterial test strains from either other bacterial strains or plants (in our laboratory we use either Arabidopsis or tobacco plant seedlings): a Petri dish containing two compartments (BI Petri dish); two Petri dishes connected with tubing; and a microtiter-based assay. The optimized procedure for the BI Petri dish system is described in this protocol and can be widely used for elucidation of potential function in interactions between diverse microbes and those plant and chemical volatiles emitted by bacteria that are most likely to mediate bacterial or plant responses to BVCs. We also describe a procedure for metabolome-based BVC profiling via dynamic (i.e., continuous airflow) or static heads...