Research Trends on Plant Associated Beneficial Bacteria as Biofertilizers for Sustainable Agriculture: An Overview

사동민,Sa, Tongmin,Chauhan, Puneet Singh 한국토양비료학회 2009 한국토양비료학회지 Vol.42 No.S2

생물비료는 아직도 한국에서는 생소한 용어다. 한국에서 생물비료라 함은 식물추출액, 퇴비류-다양한 형태의 미생물 혼합제 등으로 인식되고 있다. 그러나 최근에는 식물영양요소의 흡수나 이용도를 증진시키는 토양미생물 사용으로 언급하기도 한다. 본 개관은 식물성장을 증진시키는 것으로 알려진 PGPR 서로 다른 기작과 실질적 역할에 대하여 검토하였다. The sustainability of conventional agriculture which is characterized by input dependent and ecologically simplified food production system is vague. Chemicals and present practices used in agriculture are not only costly but also have widespread implications on human and animal health, food quality and safety and environmental quality. Thus there is a need for alternative farming practices to sustain food production for the escalating population and conserve environment for future generations. The present research scenario in the area of plant microbe interactions for maintaining sustainable agriculture suggests that the level of internal regulation in agro-ecosystems is largely dependent on the level of plant and microbial diversity present in the soil. In agro-ecosystems, biodiversity performs a variety of ecological services beyond the production of food, including recycling of nutrients, regulation of microclimate and local hydrological processes, suppression of undesirable organisms and detoxification of noxious chemicals. Controlling the soil microflora to enhance the predominance of beneficial and effective microorganisms can help improve and maintain soil chemical and physical properties. The role of beneficial soil microorganisms in sustainable productivity has been well construed. Some plant bacteria referred to as plant growth-promoting rhizobacteria (PGPR) can contribute to improve plant growth, nutrient uptake and microbial diversity when inoculated to plants. Term PGPR was initially used to describe strains of naturally occurring non-symbiotic soil bacteria have the ability to colonize plant roots and stimulate plant growth PGPR activity has been reported in strains belonging to several other genera, such as Azotobacter, Azospirillum, Arthrobacter Bacillus, Burkhokderia, Methylobacterium, and Pseudomonas etc. PGPR stimulate plant growth directly either by synthesizing hormones such as indole acetic acid or by promoting nutrition, for example, by phosphate solubilization or more generally by accelerating mineralization processes. They can also stimulate growth indirectly, acting as biocontrol agents by protecting the plant against soil borne fungal pathogens or deleterious bacteria. Present review focuses on some recent developments to evolve strategies for better biotechnological exploitation of PGPR's.

대기 CO2 상승시 인산공급이 식물체의 광합성 및 질소고정에 미치는 영향

사동민 ( Tongmin Sa ) 한국응용생명화학회 1997 Applied Biological Chemistry (Appl Biol Chem) Vol.40 No.2

The objective of this study was to examine the effect of phosphorus deficiency on nitrogen fixation and photosynthesis of nitrogen fixing soybean plant under CO₂ enrichment condition. The soybean plants(Glycine max [L.] Merr.) inoculated with Bradyrhizobium japonicum MN 110 were grown with P-stressed(0.05 mM-P) and control(1 mM-P) treatment under control(400 ㎕/L CO₂) and enrichment(800 ㎕/L CO₂) enviromental condition in the phytotron equipped with high density lamp(1000 μEm ^(-2)S^(-1)) and 28/22℃ temperature cycle for 35 days after transplanting(DAT). At 35 DAT, phosphorus deficiency decreased total dry mass by 64% in CO₂ enrichment condition, and 51% in control CO₂ condition. Total leaf area was reduced significantly by phosphorus deficiency in control and enriched COL condition but specific leaf weight was increased by P deficiency. Phosphorus deficiency significantly reduced photosynthetic rate(carbon exchange rate) and internal CO₂ concentration in leaf in both CO₂ treatments, but the degree of stress was more severe under CO₂ enrichment condition than under control CO₂ environmental condition. In phosphorus sufficient plants, CO₂ enrichment increased nodule fresh weight and total nitrogenase activity(acetylene reduction) of nodule by 30% and 41% respectively, but specific nitrogenase activity of nodule and nodule fresh weight was not affected by CO₂ enrichment in phosphorus deficient plant at 35 DAT. Total nitrogen concentrations in stem, root and nodule tissue were significantly higher in phosphorus sufficient plant grown under CO₂ enrichment, but nitrogen concentration in leaf was reduced by 30% under CO₂ enrichment. These results indicate that increasing CO₂ concentration does not affect plant growth under phosphorus deficient condition and phosphorus stress might inhibit carbohydrate utilization in whole plant and that CO₂ enrichment could not increase nodule formation and functioning under phosphorus deficient conditions and phosphorus has more important roles in nodule growth and functioning under CO₂ enrichment environments than under ambient condition.

인산결핍 조건하에서 질소고정식물체내의 Ureide 분배

사동민 ( Tongmin Sa ) 한국응용생명화학회 1997 Applied Biological Chemistry (Appl Biol Chem) Vol.40 No.3

Soybean plants inoculated Bradyrhizobium japonicum MN 110 were grown in outdoor perlite pots with nitrogen free nutrient solution containing 1.0 mM-P(control) and 0.05 mM-P(stress) and harvested at 28, 35, 42 and 49 days after transplanting (DAT) to examine the effect of phosphorus deficiency on ureide concentration of and distribution to different plant organ in nitrogen fixing soybean plant during the vegetative growth. Total dry mass of control plants increased 8.9 fold and that of phosphorus deficient plant increased 2.7 fold during the experimental period. Phosphorus deficiency reduced total phosphorus and nitrogen accumulation by 80%, 40% respectively, at 28 DAT and 93%, 84%, respectively, at 49 DAT. Nitrogen concentration was reduced by phosphorus deficiency in all tissues with leaf and stem tissues affected to a greater degree than nodule and root tissues at every sampling date. Phosphorus deficiency significantly reduced soluble reduced-N and ureide-N concentration in leaf and stem but did not affect those in root. The proportion of soluble reduced-N in leaf was reduced from 60% to 50% but increased from 10% to 20% in the roots. The proportion of ureide-N in leaf of control plants was higher than that in phosphorus deficient plants, whereas, roots of phosphorus deficient plants contained a higher proportion of ureide-N than those of control plants. These indicated that phosphorus deficiency not only inhibit nitrogen fixation of nodules but also restrict the translocation of fixed nitrogen out of the root system into the xylem.

Research Trends on Plant Associated Beneficial Bacteria as Biofertilizers for Sustainable Agriculture

Tongmin Sa(사동민),Puneet Singh Chauhan 한국토양비료학회 2009 한국토양비료학회지 Vol.42 No.S2

생물비료는 아직도 한국에서는 생소한 용어다. 한국에서 생물비료라 함은 식물추출액, 퇴비류- 다양한 형태의 미생물 혼합제 등으로 인식되고 있다. 그러나 최근에는 식물영양요소의 흡수나 이용도를 증진시키는 토양미생물 사용으로 언급하기도 한다. 본 개관은 식물성장을 증진시키는 것으로 알려진 PGPR 서로 다른 기작과 실질적 역할에 대하여 검토하였다. The sustainability of conventional agriculture which is characterized by input dependent an ecologically simplified food production system is vague. Chemicals and present practices used in agriculture are not only costly but also have widespread implications on human and animal health, food quality and safety and environmental quality. Thus there is a need for alternative farming practices to sustain food production for the escalating population and conserve environment for future generations. The present research scenario in the area of plant microbe interactions for maintainingsustainable agriculture suggests that thelevel of internal regulation in agro-ecosystems is largely dependent on the level of plant and microbial diversity present in the soil. In agro-ecosystems, biodiversity performs a variety of ecological services beyond the production of food, including recycling of nutrients, regulation of microclimate and local hydrological processes, suppression of undesirable organisms and detoxification of noxious chemicals. Controlling the soil microflora to enhance the predominance of beneficial and effective microorganisms can help improve and maintain soil chemical and physical properties. The role of beneficial soil microorganisms in sustainable productivity has been well construed. Some plant bacteria referred to as plant growthpromoting rhizobacteria (PGPR) can contribute to improve plant growth, nutrient uptake and microbial diversity when inoculated to plants. Term PGPR was initially used to describe strains of naturally occurring non-symbiotic soil bacteria have the ability to colonize plant roots and stimulateplant growth. PGPR activity has been reported in strains belonging to several other genera, such as Azotobacter, Azospirillum, Arthrobacter, Bacillus, Burkhokderia, Methylobacterium, and Pseudomonas etc. PGPR stimulate plant growth directly either by synthesizing hormones such as indole acetic acid or by promoting nutrition, for example, by phosphate solubilization or more generally by accelerating mineralization processes. They can also stimulate growth indirectly, acting as biocontrol agents by protecting the plant against soil borne fungal pathogens or deleterious bacteria. Present review focuses on some recent developments to evolve strategies for better biotechnological exploitation of PGPR’s.

Pink Pigmented Facultative Methylotrophic Bacteria (PPFMs)

Munusamy Madhaiyan,Tongmin Sa(사동민),Jai-Joung Kim(김재정) 한국토양비료학회 2004 한국토양비료학회지 Vol.37 No.4

The Endophytic Plant Growth Promoting Methylobacterium oryzae CBMB20 Modulates Plant Defense Responses while Integrating Naturally with the Seed-borne Endophytic Bacterial Community of Rice

Denver I. Walitang,Tongmin Sa(사동민) 한국토양비료학회 2021 한국토양비료학회 학술발표회 초록집 Vol.2021 No.11

Inoculation with the endophytic plant growth promoting bacteria (PGPB) leads to plant responses concurrent to the integration of the bioinoculum to the native endophytic bacterial community of the host plant. The interaction of the bioinoculum on the community of the native endophytic bacteria of the host plant is also understudied but should be an essential factor when assessing effects of bioinoculants. The study evaluated the modulation of host defense responses in rice when it is inoculated by Methylobacterium oryzae CBMB20. The effect of inoculation on the diversity and community structure of the root and shoot bacterial endophytes in Oryza sativa L. spp. indica cv. IR29 was also investigated. The defense responses observed in IR29 measured in terms of ROS and PR protein production significantly increased, but was eventually modulated by Methylobacterium oryzae CBMB20. Using Terminal Restriction Fragment Length Polymorphism (T-RFLP) analysis, CBMB20 was shown to integrate with the native endophytic bacterial community of rice without causing significant changes in the bacterial diversity and community structure. The endophytic bacterial community of the rice seedling could be traced to the original seed community suggesting that they are seed-borne endophytes. The dominant bacterial communities in rice are mainly represented by bacterial genera associated to Microbacterium, Delftia, Pseudomonas, Xanthomonas and Stenotrophomonas, Herbaspirillum, Enterobacter and Sphingomonas. In addition, Curtobacterium, Enterobacter, Stenotro-phomonas and Xanthomonas were observed in both the root and shoot community. The results showed that Methylobacterium oryzae CBMB20 could modulate defense responses and non-antagonistically integrate with the native endophytic bacterial community of the rice host opening another area on the mechanism of plant growth promotion by the bioinoculum.

Long Term Compost Fertilization Changes Soil Chemistry and Abundance of Methanogenesis and Methane Oxidation Related Genes in Rice Monocrop Paddy Fields

Chungwoo Kim(김충우),Tongmin Sa(사동민) 한국토양비료학회 2021 한국토양비료학회 학술발표회 초록집 Vol.2021 No.11

Long term compost fertilization in paddy field ecosystem is essential to maintain rice yield, soil function and fertility. However, rice fields are a major source of methane production. Monitoring long term fertilizer application and its effects on soil chemistry and the functional microbial populations are important in understanding methanogenesis and methane oxidation in paddy ecosystems. This study evaluates the changes in soil chemistry in paddy fields under long term compost fertilization and their effect on the abundance of methanegenesis, methane oxidation, and methanol oxidation related genes, namely mcrA, pmoA, and mxaF genes, respectively. Soil sampling was done on compost (Com), NPK+compost (NPKCom) and unfertilized (NF) paddy fields. The abundance of mcrA, pmoA and mxaF genes were measured using quantitative PCR (qPCR). Results show that long term compost and NPK+compost fertilization alter the soil chemistry of paddy fields with an overall increase in the organic matter (OM), total nitrogen (TN), P₂O<SUB>5</SUB>, K, Ca, Mg, and dissolved organic carbon (DOC). Consequently, the abundance of mcrA, pmoA and mxaF genes significantly increased in Com and NPKCom treatment compared to the unfertilized NF treatment. The most important soil chemical parameters that significantly and positively affect the abundance of mcrA, pmoA and mxaF genes were organic matter and dissolved organic carbon. When the soil chemical parameters and gene abundance were used as variables for cluster analyses, different fertilization treatments cluster in distinct regions. The Com and NPKCom treatments were characterized by paddy soils with elevated OM, TN, K, and P content, and higher abundance of methanogenesis, methane oxidation and methanol oxidation related genes. Long term compost fertilization of paddy field ecosystem altered the chemical characteristics of paddy fields and consequently affect the abundance of methanogenesis, methane oxidation and methanol oxidation related genes which could affect the process of methane emission and methane consumption.

Identification of free-living nitrogen-fixing bacteria and their impact on growth promotion of non-legume crop plants

Md. Rashedul Islam,Tongmin Sa(사동민) 한국토양비료학회 2012 한국토양비료학회 학술발표회 초록집 Vol.2012 No.10

Plant Growth Promotion Abilities and Formulation of Bacillus megaterium strain B 388 (MTCC 6521)

Pankaj Trivedi(판가져 트리베디),Tongmin Sa(사동민) 한국토양비료학회 2007 한국토양비료학회 학술발표회 초록집 Vol.2007 No.10

Chitosan Immobilized Aggregated Methylobacterium oryzae CBMB20 for Plant Growth Promotion (PGP) in Tomato for Mitigation of Salinity Stress

김용헌 ( Md Abdul Halim ),사동민 ( Mak Chanratana ),( Shamim Ahmed ),( Yongheon Kim ),( Tongmin Sa ) 한국환경농학회 2017 한국환경농학회 학술대회집 Vol.2017 No.-

Successful colonization of bio-inoculants face hostile environmental conditions like salinity in the rhizosphere of plant. The survivability and adaptation under stress is a major concern for bio-inoculants. Thus, the current study were focused on survivability improvement of the chitosan aggregated Methylobacterium oryzae CBMB20 and pant growth promotion (PGP) of tomato plant under salt stress. At different temperature (4, 30, 40 and 50℃) the capability of the bio-inoculant with either liquid or chitosan based formulation was observed for 3 months of storage and used to examine the effect on tomato plant under salt stress. Furthermore, the poly-β-hydroxybuterate (PHB) content, exopolysaccharide (EPS) production, biofilm formation, and microbial cell hydrophobicity as physiological parameter were studied. It was revealed that the aggregated exposed statistically significant over non-aggregated bioinoculants. In addition, to tolerate UV, heat, desiccation, low temperature, starvation, and H2O2 potentiality were higher for the aggregated M. oryzae CBMB20 than other. Particularly, chitosan immobilized aggregated M. oryzae CBMB20 exhibit 4 to 30℃ optimum storage temperature and 24.67, 36.65 and 59.53% reduction in cfu counts after 90 days of storage at temperatures 4, 30 and 40℃), respectively. Moreover, chitosan immobilized aggregated M. oryzae CBMB20 evinced by 1.9, 1.6 and 1.9-times seed germination, seedling vigor index and plant dry weight, consequently under salt. Hence, chitosan boost the lodging the aggregated bacterial cells that prompt the bio-inoculants survivability and salt stress adeptness in the rhizosphere which leads the growth and development of tomato plant.