Potential for Augmentation of Fruit Quality by Foliar Application of Bacilli Spores on Apple Tree

류충민,신정남,Wang Qi,Mei Ruhong,김의중,Jae Gu Pan 한국식물병리학회 2011 Plant Pathology Journal Vol.27 No.2

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.

Modulation of Quorum Sensing in Acyl-homoserine Lactone-Producing or -Degrading Tobacco Plants Leads to Alteration of Induced Systemic Resistance Elicited by the Rhizobacterium Serratia marcescens 90-166

류충민,최혜경,이치호,JOHN F. MURPHY,이정기,Joseph W. Kloepper 한국식물병리학회 2013 Plant Pathology Journal Vol.29 No.2

Numerous root-associated bacteria (rhizobacteria) are known to elicit induced systemic resistance (ISR) in plants. Bacterial cell-density-dependent quorum sensing (QS) is thought to be important for ISR. Here, we investigated the role of QS in the ISR elicited by the rhizobacterium, Serratia marcescens strain 90−166, in tobacco. Since S. marcescens 90−166 produces at least three QS signals, QS-mediated ISR in strain 90−166 has been difficult to understand. Therefore, we investigated the ISR capacity of two transgenic tobacco (Nicotiana tabacum) plants that contained either bacterial acylhomoserine lactone-producing (AHL) or -degrading (AiiA) genes in conjunction with S. marcescens 90−166to induce resistance against bacterial and viral pathogens. Root application of S. marcescens 90−166 increased ISR to the bacterial pathogens, Pectobacterium carotovorum subsp. carotovorum and Pseudomonas syringae pv. tabaci,in AHL plants and decreased ISR in AiiA plants. In contrast, ISR to Cucumber mosaic virus was reduced in AHL plants treated with S. marcescens 90−166 but enhanced in AiiA plants. Taken together, these data indicate that QS-dependent ISR is elicited by S. marcescens 90−166 in a pathogen-dependent manner. This study provides insight into QS-dependent ISR in tobacco elicited by S. marcescens 90−166.

Promoting Plant Protection by Root-Associated Microbes

류충민 한국식물병리학회 2013 Plant Pathology Journal Vol.29 No.2

Against friend and foe: Type 6 effectors in plant-associated bacteria

류충민 한국미생물학회 2015 The journal of microbiology Vol.53 No.3

Bacterial secretion systems play critical roles in communicationwith neighboring bacteria and in the modulation ofhost immune responses via the secretion of small proteinscalled effectors. Several secretion systems have been identifiedand these are denoted types I–VII. Of these, the type VIsecretion system (T6SS) and its effectors were only recentlyelucidated. Most studies on the role and significance of theT6SS and its effectors have focused on human pathogens. In this review, type 6 effectors from plant-associated beneficialand pathogenic bacteria are discussed, including effectorsfrom Agrobacterium tumefaciens, Dickeya dadanti, Rhizobiumleguminosarum, Pectobacterium atroseptium, Ralstoniasolanacearum, Pseudomonas syringae, Pseudomonasfluorescens, and Pseudomonas protegens. Type 6 effectors actin symbiosis, biofilm formation, virulence, and interbacterialcompetition. Understanding the impact of type 6 effectorson pathogenesis will contribute to the management of bacterialpathogens in crop plants by allowing the manipulationof intra and inter-specific interactions.

마이크로바이옴기반 신농약 개발

류충민(柳忠民) 한국농약과학회 2019 한국농약과학회 학술발표대회 논문집 Vol.2019 No.4

20세상은 미생물로 가득 차 있다. 진핵 생명체가 지구상에 나타날 때 이미 미생물은 존재하고 있었고, 이후 이들과 끝임 없는 대화를 통하여 지금까지 살아남았다. 현재 농작물을 보호하기 위한 식물-미생물 상호작용 연구가 메타지노믹스라는 기술이 소개되면서, 새로운 패러다임으로 자리잡고 있다. 이번 발표에서는 최근 본 실험실에서 진행중인 식물-미생물 마이크로바이옴연구(Phytobiome)연구를 소개할 것이다. 기존 식물마이크로자이옴 연구의 단점인 단순한 유전자분석 기반의 미생물상 조사를 넘어서 실물 미생물을 농업 포장에 직접 적용할 수 있는 분야에 대한 연구를 집중적으로 소개할 것이다. 주된 내용으로는 식물의 생장을 촉진하거나 병원균을 막아서 식물의 건강에 유익한 영향을 주는 소위 식물생장촉진근권세균(Plant Growth-Promoting Rhizobacteria, PGPR)의 토양 생태계에서의 역할과 선발 그리고 새롭게 제시된 PGPR 종에 대한 이야기들이다. 먼저 “좋은 세균 이야기” 에서는 기존 PGPR로 알려진 세균을 식물에 처리 했을 때 기존 미생물상의 천이 변화와 이러한 변화가 토양기억 기전에 의해서 전달 되는 현상을 발표할 것 이며, “나쁜 세균 이야기”에서는 토마토 재배에서 치명적인 토양 세균병인 풋마름병이 대량으로 발생한 농가 포장에서 관찰된 병억제 섬(island)현상 기전 연구를 통하여 새로운 생물적 방제 인자의 선발 예를 제시할 것이다. 마지막으로 “이상한 세균 이야기”에서는 최근 PGPR로 새롭게 선발된 신규 종(species)를 소개하고 이들에 의한 식물 건강증진에 대한 가능성을 소개할 것이다. 이번 발표를 통하여 식물마이크로바이옴의 새로운 결과와 가능성을 제시하고 앞으로 농업에서 사용하게 될 새로운 기술이 다양한 배경을 가진 과학자들에게 이해되고 응용되기를 희망한다. 특히 산업적으로 이용 가능성을 모색하고자 한다.

Bacterial volatiles and plant health

Choong-MinRyu(류충민) 한국농약과학회 2016 한국농약과학회 학술발표대회 논문집 Vol.2016 No.4

Bacillus spp. 엽면살포에 의한 가로수 및 고추의 병 방제

정준휘,류충민 한국식물병리학회 2016 식물병연구 Vol.22 No.2

Out of plant-associated bacteria, certain plant growth-promoting bacteria (PGPB) have been reported to increase plant growth and productivity and to elicit induced resistance against plant pathogens. In this study, our objective was to broaden the range of applications of leaf-colonizing PGPB for foliar parts of road tress and pepper. Total 1,056 isolates of endospore-forming bacteria from tree phylloplanes were collected and evaluated for the enzymatic activities including protease, lipase, and chitinase and antifungal capacities against two fungal pathogens, Colletotrichum graminicola and Botrytis cinerea. Fourteen isolates classified as members of the bacilli group displayed the capacity to colonize pepper leaves after spraying inoculation. Three strains, 5B6, 8D4, and 8G12, and the mixtures were employed to evaluate growth promotion, yield increase and defence responses under ἀeld condition. Additionally, foliar application of bacterial preparation was applied to the road tress in Yuseong, Daejeon, South Korea, resulted in increase of chlorophyll contents and leaf thickness, compared with non-treated control. The foliar application of microbial preparation reduced brown shot-hole disease of Prunus serrulata L. and advanced leaf abscission in Ginkgo biloba L. Collectively, our results suggest that leaf-colonizing bacteria provide potential microbial agents to increase the performance of woody plants such as tree and pepper through spray application.

Evidence for Volatile Memory in Plants: Boosting Defence Priming through the Recurrent Application of Plant Volatiles

송근철,류충민 한국분자세포생물학회 2018 Molecules and cells Vol.41 No.8

Plant defence responses to various biotic stresses via systemic acquired resistance (SAR) are induced by avirulent pathogens and chemical compounds, including certain plant hormones in volatile form, such as methyl salicylate and methyl jasmonate. SAR refers to the observation that, when a local part of a plant is exposed to elicitors, the entire plant exhibits a resistance response. In the natural environment, plants are continuously exposed to avirulent pathogens that induce SAR and volatile emissions affecting neighbouring plants as well as the plant itself. However, the underlying mechanism has not been intensively studied. In this study, we evaluated whether plants “memorise” the previous activation of plant immunity when exposed repeatedly to plant defensive volatiles such as methyl salicylate and methyl jasmonate. We hypothesised that stronger SAR responses would occur in plants treated with repeated applications of the volatile plant defence compound MeSA than in those exposed to a single or no treatment. Nicotiana benthamiana seedlings subjected to repeated applications of MeSA exhibited greater protection against Pseudomonas syringae pv. tabaci and Pectobacterium carotovorum subsp. carotovorum than the control. The increase in SAR capacity in response to repeated MeSA treatment was confirmed by analysing the defence priming of the expression of N. benthamiana Pathogenesis-Related 1a (NbPR1a) and NbPR2 by quantitative reverse-transcription PCR compared with the control. We propose the concept of plant memory of plant defence volatiles and suggest that SAR is strengthened by the repeated perception of volatile compounds in plants.

Biological Seed Treatment : Viable Population Changes of Paenibacillus polymyxa on Seed and Root and its Antagonistic Activity after Seed Formulation

최옥희,류충민,김진우 경상대학교 농업생명과학연구원 2013 농업생명과학연구 Vol.47 No.1

We analyzed the viable population changes of Paenibacillus polymyxa E681, a plant growth-promoting rhizobacterium, on seeds and roots after bioformulation at varying time intervals during the storage. The viable population of E681 on tested crop seeds sustained log 4-5 cfu/seed after 300 days of seed treatment. The ability of root colonization and inhibition of fungal mycellial growth was not influenced even after 300 days of seed treatment. The seed-soaking treatment returned better results than powder formulation, in increasing the initial population of E681 on plant roots. Collectively, it was found that E681 is a durable and stable biological control agent for application to crop seeds.

Priming of Defense-Related Genes Confers Root-Colonizing Bacilli-Elicited Induced Systemic Resistance in Pepper

양정욱,유승헌,류충민 한국식물병리학회 2009 Plant Pathology Journal Vol.25 No.4

A group of beneficial plant bacteria has been shown to increase crop growth referring to as plant growthpromoting rhizobacteria (PGPR). PGPR can decrease plant disease directly, through the production of antagonistic compounds, and indirectly, through the elicitation of a plant defense response termed induced systemic resistance (ISR). While the mechanism of PGPR-elicited ISR has been studied extensively in the model plant Arabidopsis, it is less well characterized in crop plants such as pepper. In an effort to better understand the mechanism of ISR in crop plants, we investigated the induction of ISR by Bacillus cereus strain BS107 against Xanthomonas axonopodis pv. vesicatoria in pepper leaves. We focused on the priming effect of B. cereus strain BS107 on plant defense genes as an ISR mechanism. Of ten known pepper defense genes that were previously reported to be involved in pathogen defense signaling, the expression of Capsicum annum pathogenesis-protein 4 and CaPR1 was systemically primed by the application of strain BS107 onto pepper roots confirming by quantitative- reverse transcriptase PCR. Our results provide novel genetic evidence of the priming effect of a rhizobacterium on the expression of pepper defense genes involved in ISR.