Aggregation of selected plant growth promoting Methylobacterium strains: role of cell surface components and hydrophobicity

Joe, Manoharan Melvin,Saravanan, Venkatakrishnan Sivaraj,Sa, Tongmin Springer-Verlag 2013 Archives of microbiology Vol.195 No.3

<P>The bacterial cell surface plays a major role in the bacterial aggregation that in turn plays a positive role in affecting the bacterial dispersion and survival in soil and their ability to adhere to plant surfaces. Plant growth-promoting Methylobacterium strains, Methylobacterium goesingense CBMB5, Methylobacterium sp. CBMB12, Methylobacterium oryzae CBMB20, Methylobacterium fujisawaense CBMB37, M. oryzae CBMB110 and Methylobacterium suomiense CBMB120 were evaluated for aggregation efficiency. Aggregation occurred in all test strains under high C/N growth conditions, and the strain CBMB12 showed the highest aggregation of 53.4?% at 72?h. Disaggregation compound treatment studies revealed the role of protein-protein interaction in Methylobacterium strains except CBMB110 and CBMB120 strains, where a possible carbohydrate-protein interaction is suspected. Surface layer protein extraction by LiCl followed by SDS-PAGE analysis showed the presence of proteins at molecular weights ranging from 41 to 49?kDa. Methylobacterium strains under aggregated conditions showed increased hydrophobicity compared to the cells under standard grown conditions. A relatively higher hydrophobicity of 50.1?% as evident by the adhesion with xylene was observed with strain CBMB12 under aggregated condition. This study reports the aggregation ability in plant growth-promoting Methylobacterium strains and the possible involvement of cellular components and hydrophobicity in this phenomenon.</P>

Psychrotolerance Mechanisms in Cold-Adapted Bacteria and their Perspectives as Plant Growth-Promoting Bacteria in Temperate Agriculture

Subramanian, Parthiban,Joe, Manoharan Melvin,Yim, Woo-Jong,Hong, Bo-Hui,Tipayno, Sherlyn C.,Saravanan, Venkatakrishnan Sivaraj,Yoo, Jae-Hong,Chung, Jong-Bae,Sultana, Tahera,Sa, Tong-Min Korean Society of Soil Science and Fertilizer 2011 한국토양비료학회지 Vol.44 No.4

Cold-adapted bacteria survive in extremely cold temperature conditions and exhibit various mechanisms of adaptation to sustain their regular metabolic functions. These adaptations include several physiological and metabolic changes that assist growth in a myriad of ways. Successfully sensing of the drop in temperature in these bacteria is followed by responses which include changes in the outer cell membrane to changes in the central nucleoid of the cell. Their survival is facilitated through many ways such as synthesis of cryoprotectants, cold acclimation proteins, cold shock proteins, RNA degradosomes, Antifreeze proteins and ice nucleators. Agricultural productivity in cereals and legumes under low temperature is influenced by several cold adopted bacteria including Pseudomonas, Acinetobacter, Burkholderia, Exiguobacterium, Pantoea, Rahnella, Rhodococcus and Serratia. They use plant growth promotion mechanisms including production of IAA, HCN, and ACC deaminase, phosphate solublization and biocontrol against plant pathogens such as Alternaria, Fusarium, Sclerotium, Rhizoctonia and Pythium.

Synergistic Effects of Arbuscular Mycorrhizal Fungi and Plant Growth Promoting Rhizobacteria for Sustainable Agricultural Production

Ramasamy, Krishnamoorthy,Joe, Manoharan Melvin,Kim, Ki-Yoon,Lee, Seon-Mi,Shagol, Charlotte,Rangasamy, Anandham,Chung, Jong-Bae,Islam, Md. Rashedul,Sa, Tong-Min Korean Society of Soil Science and Fertilizer 2011 한국토양비료학회지 Vol.44 No.4

Soil microorganisms play a major role in improving soil fertility and plant health. Symbiotic arbuscular mycorrhizal fungi (AMF) form a key component of the soil microbial populations. AMF form a mutualistic association with the host plant and exert a positive influence on its growth and nutrient uptake. The establishment of mycorrhizal symbioses with the host plant can positively be influenced by plant growth promoting rhizobacteria through various mechanisms such as increased spore germination and hyphal permeability in plant roots. Though there are evidences that combined interactions between AMF and PGPR can promote the plant growth however mechanisms of these interactions are poorly understood. Better understanding of the interactions between AMF and other microorganisms is necessary for maintaining soil fertility and enhancing crop production. This paper reviews current knowledge concerning the interactions between AMF and PGPR with plants and discusses on enhanced nutrient availability, biocontrol, abiotic stress tolerance and phytoremediation in sustainable agriculture.

Synergistic Effects of Arbuscular Mycorrhizal Fungi and Plant Growth Promoting Rhizobacteria for Sustainable Agricultural Production

Krishnamoorthy Ramasamy,Manoharan Melvin Joe,김기윤,이선미,Charlotte Shagol,Anandham Rangasamy1,정종배,Md. Rashedul Islam,사동민 한국토양비료학회 2011 한국토양비료학회지 Vol.44 No.4

Soil microorganisms play a major role in improving soil fertility and plant health. Symbiotic arbuscular mycorrhizal fungi (AMF) form a key component of the soil microbial populations. AMF form a mutualistic association with the host plant and exert a positive influence on its growth and nutrient uptake. The establishment of mycorrhizal symbioses with the host plant can positively be influenced by plant growth promoting rhizobacteria through various mechanisms such as increased spore germination and hyphal permeability in plant roots. Though there are evidences that combined interactions between AMF and PGPR can promote the plant growth however mechanisms of these interactions are poorly understood. Better understanding of the interactions between AMF and other microorganisms is necessary for maintaining soil fertility and enhancing crop production. This paper reviews current knowledge concerning the interactions between AMF and PGPR with plants and discusses on enhanced nutrient availability, biocontrol, abiotic stress tolerance and phytoremediation in sustainable agriculture.

Psychrotolerance Mechanisms in Cold-Adapted Bacteria and their Perspectives as Plant Growth-Promoting Bacteria in Temperate Agriculture

Parthiban Subramanian,Manoharan Melvin Joe,임우종,홍보희,Sherlyn C. Tipayno,Venkatakrishnan Sivaraj Saravanan,유재홍,정종배,Tahera Sultana,사동민 한국토양비료학회 2011 한국토양비료학회지 Vol.44 No.4

Cold-adapted bacteria survive in extremely cold temperature conditions and exhibit various mechanisms of adaptation to sustain their regular metabolic functions. These adaptations include several physiological and metabolic changes that assist growth in a myriad of ways. Successfully sensing of the drop in temperature in these bacteria is followed by responses which include changes in the outer cell membrane to changes in the central nucleoid of the cell. Their survival is facilitated through many ways such as synthesis of cryoprotectants,cold acclimation proteins, cold shock proteins, RNA degradosomes, Antifreeze proteins and ice nucleators. Agricultural productivity in cereals and legumes under low temperature is influenced by several cold adopted bacteria including Pseudomonas, Acinetobacter, Burkholderia, Exiguobacterium, Pantoea, Rahnella,Rhodococcus and Serratia. They use plant growth promotion mechanisms including production of IAA,HCN, and ACC deaminase, phosphate solublization and biocontrol against plant pathogens such as Alternaria, Fusarium, Sclerotium, Rhizoctonia and Pythium.

Halotolerant Plant Growth Promoting Bacteria Mediated Salinity Stress Amelioration in Plants

Wansik Shin,Ashaduzzaman Siddikee,Manoharan Melvin Joe,Abitha Benson,Kiyoon Kim,Gopal Selvakumar,Yeongyeong Kang,Seonyoung Jeon,Sandipan Samaddar,Poulami Chatterjee,Denver Walitang,Mak Chanratana,Tong 한국토양비료학회 2016 한국토양비료학회지 Vol.49 No.4

Soil salinization refers to the buildup of salts in soil to a level toxic to plants. The major factors that contribute to soil salinity are the quality, the amount and the type of irrigation water used. The presented review discusses the different sources and causes of soil salinity. The effect of soil salinity on biological processes of plants is also discussed in detail. This is followed by a debate on the influence of salt on the nutrient uptake and growth of plants. Salinity decreases the soil osmotic potential and hinders water uptake by the plants. Soil salinity affects the plants K uptake, which plays a critical role in plant metabolism due to the high concentration of soluble sodium (Na<SUP>+</SUP>) ions. Visual symptoms that appear in the plants as a result of salinity include stunted plant growth, marginal leaf necrosis and fruit distortions. Different strategies to ameliorate salt stress globally include breeding of salt tolerant cultivars, irrigation to leach excessive salt to improve soil physical and chemical properties. As part of an ecofriendly means to alleviate salt stress and an increasing considerable attention on this area, the review then focuses on the different plant growth promoting bacteria (PGPB) mediated mechanisms with a special emphasis on ACC deaminase producing bacteria. The various strategies adopted by PGPB to alleviate various stresses in plants include the production of different osmolytes, stress related phytohormones and production of molecules related to stress signaling such as bacterial 1-aminocyclopropane-1-carboxylate(ACC) derivatives. The use of PGPB with ACC deaminase producing trait could be effective in promoting plant growth in agricultural areas affected by different stresses including salt stress. Finally, the review ends with a discussion on the various PGPB activities and the potentiality of facultative halophilic/halotolerant PGPB in alleviating salt stress.

An Overview of Different Techniques on the Microbial Community Structure, and Functional Diversity of Plant Growth Promoting Bacteria

Kiyoon Kim,Rashedul Islam,Abitha Benson,Manoharan Melvin Joe,Walitang Denver,Mak Chanratan,Poulami Chatterjee,Yeongyeong Kang,Tongmin Sa 한국토양비료학회 2016 한국토양비료학회지 Vol.49 No.2

Soil is a dynamic biological system, in which it is difficult to determine the composition of microbial communities. Knowledge of microbial diversity and function in soils are limited because of the taxonomic and methodological limitations associated with studying the organisms. In this review, approaches to measure microbial diversity in soil were discussed. Research on soil microbes can be categorized as structural diversity, functional diversity and genetic diversity studies, and these include cultivation based and cultivation independent methods. Cultivation independent technique to evaluate soil structural diversity include different techniques such as Phospholipid Fatty Acids (PLFA) and Fatty Acid Methyl Ester (FAME) analysis. Carbon source utilization pattern of soil microorganisms by Community Level Physiological Profiling (CLPP), catabolic responses by Substrate Induced Respiration technique (SIR) and soil microbial enzyme activities are discussed. Genetic diversity of soil microorganisms using molecular techniques such as 16S rDNA analysis Denaturing Gradient Gel Electrophoresis (DGGE) / Temperature Gradient Gel Electrophoresis (TGGE), Terminal Restriction Fragment Length Polymorphism (T-RFLP), Single Strand Conformation Polymorphism (SSCP), Restriction Fragment Length Polymorphism (RFLP) / Amplified Ribosomal DNA Restriction Analysis (ARDRA) and Ribosomal Intergenic Spacer Analysis (RISA) are also discussed. The chapter ends with a final conclusion on the advantages and disadvantages of different techniques and advances in molecular techniques to study the soil microbial diversity.

An Overview of Different Techniques on the Microbial Community Structure, and Functional Diversity of Plant Growth Promoting Bacteria

Kim, Kiyoon,Islam, Rashedul,Benson, Abitha,Joe, Manoharan Melvin,Denver, Walitang,Chanratan, Mak,Chatterjee, Poulami,Kang, Yeongyeong,Sa, Tongmin Korean Society of Soil Science and Fertilizer 2016 한국토양비료학회지 Vol.49 No.2

Soil is a dynamic biological system, in which it is difficult to determine the composition of microbial communities. Knowledge of microbial diversity and function in soils are limited because of the taxonomic and methodological limitations associated with studying the organisms. In this review, approaches to measure microbial diversity in soil were discussed. Research on soil microbes can be categorized as structural diversity, functional diversity and genetic diversity studies, and these include cultivation based and cultivation independent methods. Cultivation independent technique to evaluate soil structural diversity include different techniques such as Phospholipid Fatty Acids (PLFA) and Fatty Acid Methyl Ester (FAME) analysis. Carbon source utilization pattern of soil microorganisms by Community Level Physiological Profiling (CLPP), catabolic responses by Substrate Induced Respiration technique (SIR) and soil microbial enzyme activities are discussed. Genetic diversity of soil microorganisms using molecular techniques such as 16S rDNA analysis Denaturing Gradient Gel Electrophoresis (DGGE) / Temperature Gradient Gel Electrophoresis (TGGE), Terminal Restriction Fragment Length Polymorphism (T-RFLP), Single Strand Conformation Polymorphism (SSCP), Restriction Fragment Length Polymorphism (RFLP) / Amplified Ribosomal DNA Restriction Analysis (ARDRA) and Ribosomal Intergenic Spacer Analysis (RISA) are also discussed. The chapter ends with a final conclusion on the advantages and disadvantages of different techniques and advances in molecular techniques to study the soil microbial diversity.

Halotolerant Plant Growth Promoting Bacteria Mediated Salinity Stress Amelioration in Plants

Shin, Wansik,Siddikee, Md. Ashaduzzaman,Joe, Manoharan Melvin,Benson, Abitha,Kim, Kiyoon,Selvakumar, Gopal,Kang, Yeongyeong,Jeon, Seonyoung,Samaddar, Sandipan,Chatterjee, Poulami,Walitang, Denver,Chan Korean Society of Soil Science and Fertilizer 2016 한국토양비료학회지 Vol.49 No.4

Soil salinization refers to the buildup of salts in soil to a level toxic to plants. The major factors that contribute to soil salinity are the quality, the amount and the type of irrigation water used. The presented review discusses the different sources and causes of soil salinity. The effect of soil salinity on biological processes of plants is also discussed in detail. This is followed by a debate on the influence of salt on the nutrient uptake and growth of plants. Salinity decreases the soil osmotic potential and hinders water uptake by the plants. Soil salinity affects the plants K uptake, which plays a critical role in plant metabolism due to the high concentration of soluble sodium ($Na^+$) ions. Visual symptoms that appear in the plants as a result of salinity include stunted plant growth, marginal leaf necrosis and fruit distortions. Different strategies to ameliorate salt stress globally include breeding of salt tolerant cultivars, irrigation to leach excessive salt to improve soil physical and chemical properties. As part of an ecofriendly means to alleviate salt stress and an increasing considerable attention on this area, the review then focuses on the different plant growth promoting bacteria (PGPB) mediated mechanisms with a special emphasis on ACC deaminase producing bacteria. The various strategies adopted by PGPB to alleviate various stresses in plants include the production of different osmolytes, stress related phytohormones and production of molecules related to stress signaling such as bacterial 1-aminocyclopropane-1-carboxylate (ACC) derivatives. The use of PGPB with ACC deaminase producing trait could be effective in promoting plant growth in agricultural areas affected by different stresses including salt stress. Finally, the review ends with a discussion on the various PGPB activities and the potentiality of facultative halophilic/halotolerant PGPB in alleviating salt stress.

Role of Diazotrophic Bacteria in Biological Nitrogen Fixation and Plant Growth Improvement

Wansik Shin,Rashedul Islam,Abitha Benson,Manoharan Melvin Joe,Kiyoon Kim,Selvakumar Gopal,Sandipan Samaddar,Somak Banerjee,Tongmin Sa 한국토양비료학회 2016 한국토양비료학회지 Vol.49 No.1

Though there is an abundant supply of nitrogen in the atmosphere, it cannot be used directly by the biological systems since it has to be combined with the element hydrogen before their incorporation. This process of nitrogen fixation (N₂-fixation) may be accomplished either chemically or biologically. Between the two elements, biological nitrogen fixation (BNF) is a microbiological process that converts atmospheric di-nitrogen (N₂) into plant-usable form. In this review, the genetics and mechanism of nitrogen fixation including genes responsible for it, their types and role in BNF are discussed in detail. Nitrogen fixation in the different agricultural systems using different methods is discussed to understand the actual rather than the potential N₂-fixation procedure. The mechanism by which the diazotrophic bacteria improve plant growth apart from nitrogen fixation such as inhibition of plant ethylene synthesis, improvement of nutrient uptake, stress tolerance enhancement, solubilization of inorganic phosphate and mineralization of organic phosphate is also discussed. Role of diazotrophic bacteria in the enhancement of nitrogen fixation is also dealt with suitable examples. This mini review attempts to address the importance of diazotrophic bacteria in nitrogen fixation and plant growth improvement.