Exploration of Mycobiota in Cypripedium japonicum , an Endangered Species

Cho Gyeongjun,Gang Geun-Hye,Jung Hee-Young,Kwak Youn-Sig 한국균학회 2022 Mycobiology Vol.50 No.2

Orchids live with mycorrhizal fungi in mutualism. This symbiotic relationship plays an essential role in the overall life cycle of orchids from germination, growth, settlement, and reproduction. Among the 1000 species of the orchid, the Korean lady’s slipper, Cypripedium japonicum, is known as an endangered species. Currently, only five natural habitats of the Korean lady’s slipper remain in South Korea, and the population of Korean lady’s slipper in their natural habitat is not increasing. To prevent extinction, this study was designed to understand the fungal community interacting in the rhizosphere of the Korean lady’s slipper living in the native and artificial habitats. In-depth analyses were performed to discover the vital mycorrhizal fungi contributing to habitat expansion and cultivation of the endangered orchid species. Our results suggested that Lycoperdon nigrescens contributed most to the increase in natural habitats and Russula violeipes as a characteristic of successful cultivation. And the fungi that helped L. nigrescens and R. violeipes to fit into the rhizosphere community in Korean lady’s slipper native place were Paraboeremia selaginellae and Metarhizium anisopliae, respectively. The findings will contribute to restoring and maintaining the endangered orchid population in natural habitats.

Comparison of Endophytic Microbial Community in Kiwifruit Plant Cultivars

Cho, Gyeongjun,Kim, Min-jung,Kwon, Youngho,Kwak, Youn-Sig The Korean Society of Plant Pathology 2018 Plant Pathology Journal Vol.34 No.4

The microbiome makes a significant contribution to plant health and endophytes may generate positive effects for the host. However, there is a limited knowledge available concerning the kiwifruit endophyte. Therefore, we discuss endophyte microbiome community structures among the kiwifruit cultivars. Total reads numbered 17620 in cv. Hayward, 11515 in cv. Haegeum and 13613 in cv. Jecygold. The number of OTUs was follows: 112 in cv. Hageum; and 87 in cvs. Hayward and Jecygold. Most of the identified OTUs were phylum Proteobacteria and it emerged that Actinobacteria, Firmicute and Bacteroidetes were mainly present. While the largest difference in Proteobacteria content is between cv. Haegeum and cv. Jecygold, they shared more OTUs than cv. Hayward. As well, this study revealed the presence of remarkably dominated OTU of Pseudomonas spp. in kiwifruit sap regardless of cultivars. To the best of our knowledge, this study is the first tone to investigate the kiwifruit endophyte-microbiome community.

Effect of Scenedesmus sp. CHK0059 on Strawberry Microbiota Community

Cho Gyeongjun,Jo Gyeong Seo,Lee Yejin,Kwak Youn-Sig 한국미생물·생명공학회 2022 Journal of Microbiology and Biotechnology Vol.32 No.7

Microalgae are photosynthetic cyanobacteria and eukaryotic microorganisms, mainly living in the water. In agriculture, numerous studies have been conducted to utilize microalgae as a biostimulant resource. Scenedesmus has been known to be one such microalga that can promote plant growth by secretion of auxin or cytokinin hormone analogs. However, no research has been performed on the effect of microalgae treatment on plant microbiota communities. This study was conducted to investigate the mode of action of microalgae as biostimulants in a plant microbiota perspective by using Scenedesmus sp. CHK0059 (also known as species Chlorella fusca), which has been well documented as a biostimulant for strawberries. The strawberry cultivar Keumsil was bred with Seolhyang and Maehyang as the parent cultivars. Using these three cultivars, microbiota communities were evaluated for changes in structural composition according to the CHK0059 treatment. CHK0059-treated Seolhyang, and CHK0059-untreated Maehyang were similar in microbial diversity in the endosphere. From a microbiota community perspective, the diversity change showed that CHK0059 was affected by the characteristics of the host. Conversely, when CHK0059 treatment was applied, populations of Streptomyces and Actinospica were observed in the crown endosphere.

Genetic Variation of Strawberry Fusarium Wilt Pathogen Population in Korea

Cho Gyeongjun,Kwak Youn-Sig 한국균학회 2022 Mycobiology Vol.50 No.1

Strawberries are a popular economic crop, and one of the major plantations and exporting countries is Korea in the world. The Fusarium oxysporum species complex (FOSC) is a soil-borne pathogen with genetic diversity, resulting in wilt disease in various crops. In Korea, strawberries wilt disease was first reported in the 1980s due to the infection of FOSC, causing significant economic damage every year. The causal agent, F. oxysporum f. sp. fragariae,isasoil-borne pathogen with a characteristic of FOSC that is difficult to control chemically and mutates easily. This study obtained genetic polymorphism information that was based on AFLP, of F. oxyspo- rum f. sp. fragariae 91 strains, which were isolated from strawberry cultivation sites in Gyeongsangnam-do and Chungcheongnam-do, and compared strains information, which was the isolated location, host variety, response to chemical fungicide, and antagonistic bacteria, andmyceliumphenotype.Asaresult,AFLPphylogenyfoundthattwogroupsweremainlypre- sent, and group B was present at a high frequency in Gyeongsangnam-do. Group B proved less sensitive to tebuconazole than group A through Student’s t-test. In addition, the fractions pat- tern of AFLP was calculated by comparing the strain information using PCA and PERMANOVA, and the main criteria were separated localization and strawberry varieties (PERMANOVA; p < 0.05). And tebuconazole was different with weak confidence (PERMANOVA; p < 0.10). This study suggests that the F. oxysporum f. sp. fragariae should be continuously monitored and managed, including group B, which is less chemically effective.

Investigation of relationship between antifungal activity of caryolan-1-ol and ceramide synthesis in fungi

Gyeongjun Cho,Youn-Sig Kwak 한국농약과학회 2018 한국농약과학회 학술발표대회 논문집 Vol.2018 No.10

유기농자재 사용에 따른 고추 병해 발생과 토양 미생물상 구조의 상관관계

조경준(Gyeongjun Cho),김성현(Seong-Hyeon Kim),이용복(Yong-Bok Lee),곽연식(Youn-Sig Kwak) 한국식물병리학회 2020 식물병연구 Vol.26 No.4

유기농업은 지속가능한 농업을 위해서 필요하며, 생물 다양성 유지를 위해 필수적인 경작 방법으로 전 세계적으로 성장하고 있는 농업 분야 중 하나이다. 유기농업은 인류의 건강과 환경에 유해한 영향을 끼질 수 있는 화학적 제재의 사용을 줄이고, 친환경적 동·식물성 비료, 식물 추출물, 미생물 제재 등이사용되기 때문에 소비자에게 안전한 농산물을 제공할 수 있다. 노지 고추를 대상으로 3년간 유기농업 환경과 관행농업 환경에서 주요 병해 발생과 토양 미생물상의 조사하였다. 토양 미생물상의 차이는 차세대 염기서열 분석 기법을 활용하여 조사하였으며, 유기농업에 사용되는 제제의 종류에 따라 토양 미생물상이 다르게 형성되었다. 바이러스, 탄저병에 대해서는 관행농업에서의 병 발생률이 낮았으나, 청고병은 미생물 제재 사용에 의해 병 발생률이 낮게 나타났다. 미생물 제재를 사용한 토양에서 투입된 미생물이 토양 미생물에서 검출되었으며, 이는 미생물이 실제 토양에 정착했음을 시사한다. Organic farming is necessary to sustainable agriculture, preserve biodiversity and continued growth the sector in agriculture. In organic farming, reduced usage of chemical agents that adversely affect human health and environment, employing amino acids and oil cake fertilizer, plant extracts, and microbial agents are used to provide safe agricultural products to consumers. To investigation microbiome structure, we proceeded on the pepper plant with difference fertilizers and treatments in organic agriculture for three years. The microbial communities were analyzed by the next generation sequencing approach. Difference soil microbiota communities were discovered base on organic fertilizer agents. Occurrences of virus and anthracnose diseases had a low incidence in conventional farming, whereas bacteria wilt disease had a low incidence in microbial agents treated plots. Microbe agents, which applied in soil, were detected in the microbial community and the funding suggested the applied microbes successfully colonized in the organic farming environment.

Effect of microalgae Chlorella fusca CHK0059 on the microbiota community in nursery strawberry

Lee Yejin,Cho Gyeongjun,조경서,곽연식 한국원예학회 2023 Horticulture, Environment, and Biotechnology Vol.64 No.4

Chlorella is an autotrophic and eukaryotic microorganism that photosynthesizes using chlorophyll. In the last few decades, green algae (Chlorophyceae) have been evaluated as highly eff ective biofertilizers in agriculture. Representatively Chlorella vulagris, C. pyrenoidosa , and Scenedesmus obliquus were developed as eco-friendly and eff ective biofertilizers for many crops. Recently, C. fusca strain CHK0059 has been reported to greatly improve the productivity of various crops, but the mode of action of C. fusca CHK0059 as a biofertilizer and biocontrol agent has remained unveiled. The purpose of this study was to evaluate how the strawberry’s phenotype was altered and unveil microbiota community shifting by the C. fusca CHK0059 treatment using 16 S rRNA sequencing and metagenomic analyses. Total chlorophyll contents per leaf area were 4.38 μg/cm² in the control and 6.47 μg/cm² in the C. fusca CHK0059 treated group, the rate was 47.71% higher than in untreated strawberries. Microbiota communities in the crown endosphere, and root endosphere were not signifi - cantly aff ected by C. fusca CHK0059 treatment. However, the strawberry rhizosphere microbiota community responded, and microbiota metabolic pathways were also alerted by C. fusca CHK0059. These results provide a new approach to the value and mechanism of microalgae in organic farming.

Analysis of Endophytic Bacterial Communities and Investigation of Core Taxa in Apple Trees

Yejin Lee,Gyeongjun Cho,김다란,곽연식 한국식물병리학회 2023 Plant Pathology Journal Vol.39 No.4

Fire blight disease, caused by Erwinia amylovora, is a devastating affliction in apple cultivation worldwide. Chemical pesticides have exhibited limited effectiveness in controlling the disease, and biological control options for treating fruit trees are limited. Therefore, a relatively large-scale survey is necessary to develop microbial agents for apple trees. Here we collected healthy apple trees from across the country to identify common and core bacterial taxa. We analyzed the endophytic bacterial communities in leaves and twigs and discovered that the twig bacterial communities were more conserved than those in the leaves, regardless of the origin of the sample. This finding indicates that specific endophytic taxa are consistently present in healthy apple trees and may be involved in vital functions such as disease prevention and growth. Furthermore, we compared the community metabolite pathway expression rates of these endophyte communities with those of E. amylovora infected apple trees and discovered that the endophyte communities in healthy apple trees not only had similar community structures but also similar metabolite pathway expression rates. Additionally, Pseudomonas and Methylobacterium-Methylorobrum were the dominant taxa in all healthy apple trees. Our findings provide valuable insights into the potential roles of endophytes in healthy apple trees and inform the development of strategies for enhancing apple growth and resilience. Moreover, the similarity in cluster structure and pathway analysis between healthy orchards was mutually reinforcing, demonstrating the power of microbiome analysis as a tool for identifying factors that contribute to plant health.

Complete Genome Sequence of Massilia sp. KACC 81254BP Reveals a Potential for Degrading Polyhydroxyalkanoates

An Sihyun,Cho Gyeongjun,Ahn Jae-Hyung,Weon Hang-Yeon,Kim Dayeon,Ko Young-Joon,Yeon Jehyeong,Chung Joon-hui,Choi Han Suk,Heo Jun 한국미생물·생명공학회 2024 한국미생물·생명공학회지 Vol.52 No.1

Massilia sp. KACC 81254BP, isolated from a landfill on Jeju Island, Republic of Korea, possesses the capability to degrade polyhydroxyalkanoates (PHAs). The genomic analysis of strain KACC 81254BP consists of a circular chromosome comprising 5,028,452 base pairs with a DNA G+C content of 64.6%. This complete genome consists of a total of 4,513 genes, including those encoding the PHA degradation enzyme (PhaZ). This study offers valuable genomic insights into the enzymes responsible for degrading polyester plastics.

Investigation of Chlorella Effectiveness as Biofertilizer in Strawberry Nursery Period

Gyeong Seo Jo,Gyeongjun Cho,Youn-Sig Kwak 한국농약과학회 2021 한국농약과학회 학술발표대회 논문집 Vol.2021 No.11

Chlorella is an autotrophic and eukaryotic microorganism that photosynthesizes using chlorophyll. In researches last few decades, microalgae including Chlorella was evaluated as highly effective biofertilizers in agriculture. Some microalgae were reported to prevend plant disease and to greatly improve the productivity of crops but their mode of action was not well understood. This study was planned to evaluate how the phenotype of strawberries is altered by Chlorella before analyzing the interaction between plant bacterial community and Chlorella using metagenomic 16S rRNA sequencing. A Chlorella, named CHK0059, was treated once or twice a week for 51 days in the strawberry nursery stage. After sampling, the phenotype was evaluated with a number of leaves, a weight of an above-ground part, a length of a stem, and a density of chlorophyll in leaves. As for the phenotype according to CHK0059 treatment, stem length was significantly lower than no treatment, and the total chlorophyll content was significantly higher than no treatment. This study confirmed that Chlorella has a positive effect on strawberry productivity as in previous reports. Based on the same sample of this study, further studies will be conducted to understand the mode of action of CHK0059 in terms of interaction among the Chlorella, plant disease, and the strawberry bacterial community.