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da Cunha ET, Pedrolo AM, Arisi ACM. Thermal and salt stress effects on the survival of plant growth-promoting bacteria Azospirillum brasilense in inoculants for maize cultivation. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2024; 104:5360-5367. [PMID: 38324183 DOI: 10.1002/jsfa.13366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 02/03/2024] [Accepted: 02/07/2024] [Indexed: 02/08/2024]
Abstract
BACKGROUND The plant growth-promoting bacteria (PGPB) Azospirillum brasilense is widely used as an inoculant for important grass crops, providing numerous benefits to the plants. However, one limitation to develop viable commercial inoculants is the control of PGPB survival, requiring strategies that guarantee their survival during handling and field application. The application of sublethal stress appears to be a promising strategy to increase bacterial cells tolerance to adverse environmental conditions since previous stress induces the activation of physiological protection in bacterial cell. In this work, we evaluated the effects of thermal and salt stresses on the survival of inoculant containing A. brasilense Ab-V5 and Ab-V6 strains and we monitored A. brasilense viability in inoculated maize roots after stress treatment of inoculant. RESULTS Thermal stress application (> 35 °C) in isolated cultures for both strains, as well as salt stress [sodium chloride (NaCl) concentrations > 0.3 mol L-1], resulted in growth rate decline. The A. brasilense enumeration in maize roots obtained by propidium monoazide quantitative polymerase chain reaction (PMA-qPCR), for inoculated maize seedlings grown in vitro for 7 days, showed that there is an increased number of viable cells after the salt stress treatment, indicating that A. brasilense Ab-V5 and Ab-V6 strains are able to adapt to salt stress (0.3 mol L-1 NaCl) growth conditions. CONCLUSION Azospirillum brasilense Ab-V5 and Ab-V6 strains had potential for osmoadaptation and salt stress, resulting in increased cell survival after inoculation in maize plants. © 2024 Society of Chemical Industry.
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Affiliation(s)
- Elisandra Triches da Cunha
- CAL CCA UFSC, Food Science and Technology Department, Agrarian Science Center, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Ana Marina Pedrolo
- CAL CCA UFSC, Food Science and Technology Department, Agrarian Science Center, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Ana Carolina Maisonnave Arisi
- CAL CCA UFSC, Food Science and Technology Department, Agrarian Science Center, Federal University of Santa Catarina, Florianópolis, Brazil
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Wang J, Wang Y, Lou H, Wang W. AlgU controls environmental stress adaptation, biofilm formation, motility, pyochelin synthesis and antagonism potential in Pseudomonas protegens SN15-2. Microbiol Res 2023; 272:127396. [PMID: 37141849 DOI: 10.1016/j.micres.2023.127396] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/24/2023] [Accepted: 04/25/2023] [Indexed: 05/06/2023]
Abstract
Pseudomonas protegens is a typical plant-growth-promoting rhizobacterium that can serve as an agricultural biocontrol agent. The extracytoplasmic function (ECF) sigma factor AlgU is a global transcription regulator controlling stress adaption and virulence in Pseudomonas aeruginosa and Pseudomonas syringae. Meanwhile, the regulatory role of AlgU in the biocontrol ability of P.protegens has been poorly studied. In this study, deletion mutations of algU and its antagonist coding gene mucA were constructed to investigate the function of AlgU in P.protegens SN15-2 via phenotypic experiment and transcriptome sequencing analysis. On the basis of phenotypic analyses, it was concluded that the AlgU whose transcription was induced by osmotic stress and oxidative stress positively regulated biofilm formation and tolerance towards osmotic, heat, and oxidation stresses, while it negatively regulated motility, pyochelin synthesis, and the ability to inhibit pathogens. On the basis of the RNA-seq analysis, compared to the wild-type strain, 12 genes were significantly upregulated and 77 genes were significantly downregulated in ΔalgU, while 407 genes were significantly upregulated and 279 genes were significantly downregulated in ΔmucA, indicating the involvement of AlgU in several cellular processes, mainly related to resistance, carbohydrate metabolism, membrane formation, alginate production, the type VI secretion system, flagella motility and pyochelin production. Our findings provide insights into the important role of AlgU of P.protegens in biocontrol, which is of value in improving the biocontrol ability of P.protegens.
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Affiliation(s)
- Jian Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Yaping Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Haibo Lou
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Wei Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.
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da Cunha ET, Pedrolo AM, Arisi ACM. Effects of sublethal stress application on the survival of bacterial inoculants: a systematic review. Arch Microbiol 2023; 205:190. [PMID: 37055599 DOI: 10.1007/s00203-023-03542-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 04/04/2023] [Accepted: 04/05/2023] [Indexed: 04/15/2023]
Abstract
The use of commercial bacterial inoculants formulated with plant-growth promoting bacteria (PGPB) in agriculture has shown significant prominence in recent years due to growth-promotion benefits provided to plants through different mechanisms. However, the survival and viability of bacterial cells in inoculants are affected during use and may decrease their effectiveness. Physiological adaptation strategies have attracted attention to solve the viability problem. This review aims to provide an overview of research on selecting sublethal stress strategies to increase the effectiveness of bacterial inoculants. The searches were performed in November 2021 using Web of Science, Scopus, PubMed, and Proquest databases. The keywords "nitrogen-fixing bacteria", "plant growth-promoting rhizobacteria", "azospirillum", "pseudomonas", "rhizobium", "stress pre-conditioning", "adaptation", "metabolic physiological adaptation", "cellular adaptation", "increasing survival", "protective agent" and "protective strategy" were used in the searches. A total of 2573 publications were found, and 34 studies were selected for a deeper study of the subject. Based on the studies analysis, gaps and potential applications related to sublethal stress were identified. The most used strategies included osmotic, thermal, oxidative, and nutritional stress, and the primary cell response mechanism to stress was the accumulation of osmolytes, phytohormones, and exopolysaccharides (EPS). Under sublethal stress, the inoculant survival showed positive increments after lyophilization, desiccation, and long-term storage processes. The effectiveness of inoculant-plants interaction also had positive increments after sublethal stress, improving plant development, disease control, and tolerance to environmental stresses compared to unappealed inoculants.
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Affiliation(s)
- Elisandra Triches da Cunha
- CAL CCA UFSC, Food Science and Technology Department, Federal University of Santa Catarina, Rod. Admar Gonzaga, 1346, Florianópolis, SC, 88034-001, Brazil
| | - Ana Marina Pedrolo
- CAL CCA UFSC, Food Science and Technology Department, Federal University of Santa Catarina, Rod. Admar Gonzaga, 1346, Florianópolis, SC, 88034-001, Brazil
| | - Ana Carolina Maisonnave Arisi
- CAL CCA UFSC, Food Science and Technology Department, Federal University of Santa Catarina, Rod. Admar Gonzaga, 1346, Florianópolis, SC, 88034-001, Brazil.
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Bonaterra A, Badosa E, Daranas N, Francés J, Roselló G, Montesinos E. Bacteria as Biological Control Agents of Plant Diseases. Microorganisms 2022; 10:microorganisms10091759. [PMID: 36144361 PMCID: PMC9502092 DOI: 10.3390/microorganisms10091759] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 08/18/2022] [Accepted: 08/24/2022] [Indexed: 12/04/2022] Open
Abstract
Biological control is an effective and sustainable alternative or complement to conventional pesticides for fungal and bacterial plant disease management. Some of the most intensively studied biological control agents are bacteria that can use multiple mechanisms implicated in the limitation of plant disease development, and several bacterial-based products have been already registered and marketed as biopesticides. However, efforts are still required to increase the commercially available microbial biopesticides. The inconsistency in the performance of bacterial biocontrol agents in the biological control has limited their extensive use in commercial agriculture. Pathosystem factors and environmental conditions have been shown to be key factors involved in the final levels of disease control achieved by bacteria. Several biotic and abiotic factors can influence the performance of the biocontrol agents, affecting their mechanisms of action or the multitrophic interaction between the plant, the pathogen, and the bacteria. This review shows some relevant examples of known bacterial biocontrol agents, with especial emphasis on research carried out by Spanish groups. In addition, the importance of the screening process and of the key steps in the development of bacterial biocontrol agents is highlighted. Besides, some improvement approaches and future trends are considered.
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Insight into a Successful Development of Biocontrol Agents: Production, Formulation, Packaging, and Shelf Life as Key Aspects. HORTICULTURAE 2022. [DOI: 10.3390/horticulturae8040305] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
Biocontrol agents (BCAs) have been proposed and studied over recent decades as a suitable alternative to diminish or substitute synthetic fungicides used to control pre- and postharvest diseases. However, the development of BCAs has many constraints and obstacles that would have to be overcome before they could be successfully implemented in the market. For the BCA commercial development, the microorganism should be mass-produced on a large-scale, and, independently of the method used for the production, a particular plan regarding the formulation of BCAs by multidisciplinary approaches (liquid or solid) is required to optimize the yield, efficacy, and shelf life of the developed product. Unfortunately, not all BCAs can survive the conditions imposed during the formulation process. Improved stability can be achieved by either using special conditions during growing or by adding protective substances to the formulation medium. Finally, BCAs should be formulated in such a way as to guarantee long-term stability and ease of application of the product. Therefore, an accurate range of the packaging conditions should be considered to extend the shelf life of the formulated product, preferably up to two years. Herein, we discussed the main aspects regarding the production, formulation, packaging, and shelf life of BCAs.
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Kumar S, Diksha, Sindhu SS, Kumar R. Biofertilizers: An ecofriendly technology for nutrient recycling and environmental sustainability. CURRENT RESEARCH IN MICROBIAL SCIENCES 2022; 3:100094. [PMID: 35024641 PMCID: PMC8724949 DOI: 10.1016/j.crmicr.2021.100094] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 12/09/2021] [Accepted: 12/09/2021] [Indexed: 01/02/2023] Open
Abstract
Agriculture plays an important role in a country's economy. In modern intensive agricultural practices, chemical fertilizers and pesticides are applied on large scale to increase crop production in order to meet the nutritional requirements of the ever-increasing world population. However, rapid urbanization with shrinking agricultural lands, dramatic change in climatic conditions and extensive use of agrochemicals in agricultural practices has been found to cause environmental disturbances and public health hazards affecting food security and sustainability in agriculture. Besides this, agriculture soils are continuously losing their quality and physical properties as well as their chemical (imbalance of nutrients) and biological health due to indiscriminate use of agrochemicals. Plant-associated microbes with their plant growth- promoting traits have enormous potential to solve these challenges and play a crucial role in enhancing plant biomass and crop yield under greenhouse and field conditions. The beneficial mechanisms of plant growth improvement include enhanced availability of nutrients (i.e., N, P, K, Zn and S), phytohormone modulation, biocontrol of phytopathogens and amelioration of biotic and abiotic stresses. This plant-microbe interplay is indispensable for sustainable agriculture and these microbes may perform essential role as an ecological engineer to reduce the use of chemical fertilizers. Various steps involved for production of solid-based or liquid biofertilizer formulation include inoculum preparation, addition of cell protectants such as glycerol, lactose, starch, a good carrier material, proper packaging and best delivery methods. In addition, recent developments of formulation include entrapment/microencapsulation, nano-immobilization of microbial bioinoculants and biofilm-based biofertilizers. Thus, inoculation with beneficial microbes has emerged as an innovative eco-friendly technology to feed global population with available resources. This review critically examines the current state-of-art on use of microbial strains as biofertilizers in different crop systems for sustainable agriculture and in maintaining soil fertility and enhancing crop productivity. It is believed that acquisition of advanced knowledge of plant-PGPR interactions, bioengineering of microbial communities to improve the performance of biofertilizers under field conditions, will help in devising strategies for sustainable, environment-friendly and climate smart agricultural technologies to deliver short and long terms solutions for improving crop productivity to feed the world in a more sustainable manner.
Modern intensive agricultural practices face numerous challenges that pose major threats to global food security. In order to address the nutritional requirements of the ever-increasing world population, chemical fertilizers and pesticides are applied on large scale to increase crop production. However, the injudicious use of agrochemicals has resulted in environmental pollution leading to public health hazards. Moreover, agriculture soils are continuously losing their quality and physical properties as well as their chemical (imbalance of nutrients) and biological health. Plant-associated microbes with their plant growth- promoting traits have enormous potential to solve these challenges and play a crucial role in enhancing plant biomass and crop yield. The beneficial mechanisms of plant growth improvement include enhanced nutrient availability, phytohormone modulation, biocontrol of phytopathogens and amelioration of biotic and abiotic stresses. Solid-based or liquid bioinoculant formulation comprises inoculum preparation, addition of cell protectants such as glycerol, lactose, starch, a good carrier material, proper packaging and best delivery methods. Recent developments of formulation include entrapment/microencapsulation, nano-immobilization of microbial bioinoculants and biofilm-based biofertilizers. This review critically examines the current state-of-art on use of microbial strains as biofertilizers and the important roles performed by these beneficial microbes in maintaining soil fertility and enhancing crop productivity.
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Key Words
- ABA, Abscisic acid
- ACC, 1-aminocyclopropane-1-carboxylic acid
- AM, Arbuscular mycorrhiza
- APX, Ascorbate peroxidase
- BGA, Blue green algae
- BNF, Biological nitrogen fixation
- Beneficial microorganisms
- Biofertilizers
- CAT, Catalase
- Crop production
- DAPG, 2, 4-diacetyl phloroglucinol
- DRB, Deleterious rhizospheric bacteria
- GA, Gibberellic acid
- GPX, Glutathione/thioredoxin peroxidase
- HCN, Hydrogen cyanide
- IAA, Indole acetic acid
- IAR, Intrinsic antibiotic resistance
- ISR, Induced systemic resistance
- KMB, Potassium mobilizing bacteria
- KSMs, Potassium-solubilizing microbes
- MAMPs, Microbes associated molecular patterns
- PAMPs, Pathogen associated molecular patterns
- PCA, Phenazine-1-carboxylic acid
- PGP, Plant growth-promoting
- PGPR, Plant growth-promoting rhizobacteria
- POD, Peroxidase
- PSB, Phosphate-solubilizing bacteria
- Rhizosphere
- SAR, Systemic acquired resistance
- SOB, Sulphur oxidizing bacteria
- Soil fertility
- Sustainable agriculture
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Affiliation(s)
- Satish Kumar
- Department of Microbiology, CCS Haryana Agricultural University, Hisar 125004, India
| | - Diksha
- Department of Microbiology, CCS Haryana Agricultural University, Hisar 125004, India
| | - Satyavir S Sindhu
- Department of Microbiology, CCS Haryana Agricultural University, Hisar 125004, India
| | - Rakesh Kumar
- Department of Microbiology, CCS Haryana Agricultural University, Hisar 125004, India
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Craig K, Johnson BR, Grunden A. Leveraging Pseudomonas Stress Response Mechanisms for Industrial Applications. Front Microbiol 2021; 12:660134. [PMID: 34040596 PMCID: PMC8141521 DOI: 10.3389/fmicb.2021.660134] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 04/12/2021] [Indexed: 12/25/2022] Open
Abstract
Members of the genus Pseudomonas are metabolically versatile and capable of adapting to a wide variety of environments. Stress physiology of Pseudomonas strains has been extensively studied because of their biotechnological potential in agriculture as well as their medical importance with regards to pathogenicity and antibiotic resistance. This versatility and scientific relevance led to a substantial amount of information regarding the stress response of a diverse set of species such as Pseudomonas chlororaphis, P. fluorescens, P. putida, P. aeruginosa, and P. syringae. In this review, environmental and industrial stressors including desiccation, heat, and cold stress, are cataloged along with their corresponding mechanisms of survival in Pseudomonas. Mechanisms of survival are grouped by the type of inducing stress with a focus on adaptations such as synthesis of protective substances, biofilm formation, entering a non-culturable state, enlisting chaperones, transcription and translation regulation, and altering membrane composition. The strategies Pseudomonas strains utilize for survival can be leveraged during the development of beneficial strains to increase viability and product efficacy.
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Affiliation(s)
- Kelly Craig
- AgBiome Inc., Research Triangle Park, NC, United States
| | | | - Amy Grunden
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, United States
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8
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Hyperosmotic Adaptation of Pseudomonas protegens SN15-2 Helps Cells to Survive at Lethal Temperatures. BIOTECHNOL BIOPROC E 2020. [DOI: 10.1007/s12257-019-0430-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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9
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Choline–betaine pathway contributes to hyperosmotic stress and subsequent lethal stress resistance in Pseudomonas protegens SN15-2. J Biosci 2020. [DOI: 10.1007/s12038-020-00060-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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10
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Maciag T, Krzyzanowska DM, Jafra S, Siwinska J, Czajkowski R. The Great Five-an artificial bacterial consortium with antagonistic activity towards Pectobacterium spp. and Dickeya spp.: formulation, shelf life, and the ability to prevent soft rot of potato in storage. Appl Microbiol Biotechnol 2020; 104:4547-4561. [PMID: 32215712 PMCID: PMC7190590 DOI: 10.1007/s00253-020-10550-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 02/17/2020] [Accepted: 03/15/2020] [Indexed: 11/18/2022]
Abstract
Abstract “The Great Five” (GF) is an artificial bacterial consortium developed to protect potato tubers from soft rot caused by Pectobacterium spp. and Dickeya spp. To investigate the commercialization potential of the GF, we developed liquid and powder formulations of the consortium and of each of the comprising strains (Serratia plymuthica strain A294, Enterobacter amnigenus strain A167, Rahnella aquatilis strain H145, Serratia rubidaea strain H440, and S. rubidaea strain H469). To form powders, the cells were lyophilized using a newly developed lyoprotectant: Reagent PS. The shelf life of the formulations stored at 8 and 22 °C was monitored for a period of 12 months. The longest shelf life was obtained for formulations stored at 8 °C; however, the viability of all formulations was negatively affected at 22 °C. For the consortium, a 2.5 log10 cfu (colony forming units) drop in cell number was recorded for the liquid formulation after 6 months, while in case of powders, the drop remained below 1 log10 cfu following 12 months. The ability of the powder formulations to preserve biocontrol activity of the consortium was tested on potato tubers treated with the formulations and a mixture of the soft rot pathogens. The inoculated tubers were stored for 6 months at 8 °C to mimic commercial storage conditions. Soft rot severity and incidence on potato tubers treated with formulations were significantly reduced (62–75% and 48–61%, respectively) in comparison to positive control with pathogens alone. The potential use of the newly developed formulations of “The Great Five” for the biocontrol of soft rot is discussed. Key Points • An innovative reagent to protect bacterial cells during lyophilization was developed. • Powder formulations of “The Great Five” prolonged its shelf life. • The powder-formulated “The Great Five” was active against soft rot bacteria on potato tubers. Electronic supplementary material The online version of this article (10.1007/s00253-020-10550-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tomasz Maciag
- Division of Biological Plant Protection, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Dorota M Krzyzanowska
- Division of Biological Plant Protection, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Sylwia Jafra
- Division of Biological Plant Protection, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Joanna Siwinska
- Division of Plant Protection and Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Robert Czajkowski
- Division of Biologically Active Compounds, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland.
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11
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Wang X, Tang D, Wang W. Adaptation strategies of
Pseudomonas protegens
SN15‐2 to hyperosmotic growth environment. J Appl Microbiol 2020; 128:1720-1734. [DOI: 10.1111/jam.14582] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 01/02/2020] [Accepted: 01/12/2020] [Indexed: 12/12/2022]
Affiliation(s)
- X. Wang
- State Key Laboratory of Bioreactor Engineering East China University of Science and Technology Shanghai China
| | - D. Tang
- State Key Laboratory of Bioreactor Engineering East China University of Science and Technology Shanghai China
| | - W. Wang
- State Key Laboratory of Bioreactor Engineering East China University of Science and Technology Shanghai China
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12
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Anhydrobiotic engineering for the endophyte bacterium Kosakonia radicincitans by osmoadaptation and providing exogenously hydroxyectoine. World J Microbiol Biotechnol 2019; 36:6. [DOI: 10.1007/s11274-019-2780-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 11/30/2019] [Indexed: 10/25/2022]
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13
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Effect of tris(2-carboxyethyl)phosphine and tertiary butyl alcohol on the performance of convection polymerase chain reaction. Mol Biol Rep 2018; 46:639-645. [PMID: 30484105 DOI: 10.1007/s11033-018-4519-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 11/22/2018] [Indexed: 10/27/2022]
Abstract
Rapid and on-site DNA-based molecular detection has become increasingly important for sensitive, specific, and timely detection and treatment of various diseases. To prepare and store biomolecule-containing reagents stably, reducing agents are used during protein preparation, and freeze-drying technology has been applied to the protein reagents. Some of the additives used during these processes may affect subsequent processes such as polymerase chain reaction (PCR). In this study, we evaluated the impact of TCEP, a reducing agent, and TBA, a freeze-drying medium, on the performance of convection PCR (cPCR) using a battery-operable PCR device. Singleplex cPCR detection of a 249 bp amplicon from human genomic DNA suggested that approximately 82% of performance was achieved in the presence of 0.1 mM TCEP and 1% TBA. The limit of detection and the minimum number of cycles at which amplicons began to appear was a little lower (~ 82% efficiency) or higher (20 vs 15 cycles), respectively, in the chemical-treated group than in the control group. With larger amplicons of 500 bp, the chemical-treated group revealed approximately 78% of performance and amplicons started to appear at 20 cycles of cPCR in both groups. Similar results were obtained with multiplex cPCR amplification.
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Lobo CB, Juárez Tomás MS, Viruel E, Ferrero MA, Lucca ME. Development of low-cost formulations of plant growth-promoting bacteria to be used as inoculants in beneficial agricultural technologies. Microbiol Res 2018; 219:12-25. [PMID: 30642462 DOI: 10.1016/j.micres.2018.10.012] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/23/2018] [Accepted: 10/31/2018] [Indexed: 01/10/2023]
Abstract
Phosphorus is one of the main macronutrients for plant development. Despite its large deposits in soils, it is scarcely available for plants. Phosphate-solubilizing bacteria, belonging to the group of plant growth-promoting rhizobacteria (PGPR), are capable of mobilizing deposits of insoluble phosphates in the soil. The use of PGPR as inoculants provides an environmentally sustainable approach to increase crop production. The effectiveness of inoculants depends on their proper production, formulation and storage in order to ensure the application of the required number of viable microbial cells. In order to develop inexpensive technology, low-cost compounds for biomass production and protection should be used. After the biomass production process, the product should be formulated in a liquid or a solid form, taking into account required storage time, use of protectors/carriers, storage conditions (temperature, humidity, etc.), ease of application and maintenance of beneficial effects on crops. Careful determination of these optimal conditions would ensure a low-cost efficient inoculant that would promote the growth and yield of various crops.
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Affiliation(s)
- Constanza Belén Lobo
- Planta Piloto de Procesos Industriales Microbiológicos (PROIMI)-CONICET, Avenida Belgrano y Pasaje Caseros, San Miguel de Tucumán T4001MVB, Tucumán, Argentina.
| | - María Silvina Juárez Tomás
- Planta Piloto de Procesos Industriales Microbiológicos (PROIMI)-CONICET, Avenida Belgrano y Pasaje Caseros, San Miguel de Tucumán T4001MVB, Tucumán, Argentina.
| | - Emilce Viruel
- Instituto de Investigación Animal del Chaco Semiárido (IIACS), Centro de Investigaciones Agropecuarias (CIAP), Instituto Nacional de Tecnología Agropecuaria (INTA), Leales, Tucumán, Argentina.
| | - Marcela Alejandra Ferrero
- Planta Piloto de Procesos Industriales Microbiológicos (PROIMI)-CONICET, Avenida Belgrano y Pasaje Caseros, San Miguel de Tucumán T4001MVB, Tucumán, Argentina; Microbiología Superior, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán (UNT), Ayacucho 471, San Miguel de Tucumán T4000INI, Tucumán, Argentina.
| | - María Ester Lucca
- Planta Piloto de Procesos Industriales Microbiológicos (PROIMI)-CONICET, Avenida Belgrano y Pasaje Caseros, San Miguel de Tucumán T4001MVB, Tucumán, Argentina; Microbiología Superior, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán (UNT), Ayacucho 471, San Miguel de Tucumán T4000INI, Tucumán, Argentina.
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15
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Berninger T, González López Ó, Bejarano A, Preininger C, Sessitsch A. Maintenance and assessment of cell viability in formulation of non-sporulating bacterial inoculants. Microb Biotechnol 2018; 11:277-301. [PMID: 29205959 PMCID: PMC5812248 DOI: 10.1111/1751-7915.12880] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 09/11/2017] [Accepted: 10/08/2017] [Indexed: 01/20/2023] Open
Abstract
The application of beneficial, plant-associated microorganisms is a sustainable approach to improving crop performance in agriculture. However, microbial inoculants are often susceptible to prolonged periods of storage and deleterious environmental factors, which negatively impact their viability and ultimately limit efficacy in the field. This particularly concerns non-sporulating bacteria. To overcome this challenge, the availability of protective formulations is crucial. Numerous parameters influence the viability of microbial cells, with drying procedures generally being among the most critical ones. Thus, technological advances to attenuate the desiccation stress imposed on living cells are key to successful formulation development. In this review, we discuss the core aspects important to consider when aiming at high cell viability of non-sporulating bacteria to be applied as microbial inoculants in agriculture. We elaborate the suitability of commonly applied drying methods (freeze-drying, vacuum-drying, spray-drying, fluidized bed-drying, air-drying) and potential measures to prevent cell damage from desiccation (externally applied protectants, stress pre-conditioning, triggering of exopolysaccharide secretion, 'helper' strains). Furthermore, we point out methods for assessing bacterial viability, such as colony counting, spectrophotometry, microcalorimetry, flow cytometry and viability qPCR. Choosing appropriate technologies for maintenance of cell viability and evaluation thereof will render formulation development more efficient. This in turn will aid in utilizing the vast potential of promising, plant beneficial bacteria as sustainable alternatives to standard agrochemicals.
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Affiliation(s)
- Teresa Berninger
- AIT Austrian Institute of Technology GmbHCenter for Health and BioresourcesBioresources UnitKonrad‐Lorenz‐Straße 243430TullnAustria
| | - Óscar González López
- AIT Austrian Institute of Technology GmbHCenter for Health and BioresourcesBioresources UnitKonrad‐Lorenz‐Straße 243430TullnAustria
| | - Ana Bejarano
- AIT Austrian Institute of Technology GmbHCenter for Health and BioresourcesBioresources UnitKonrad‐Lorenz‐Straße 243430TullnAustria
| | - Claudia Preininger
- AIT Austrian Institute of Technology GmbHCenter for Health and BioresourcesBioresources UnitKonrad‐Lorenz‐Straße 243430TullnAustria
| | - Angela Sessitsch
- AIT Austrian Institute of Technology GmbHCenter for Health and BioresourcesBioresources UnitKonrad‐Lorenz‐Straße 243430TullnAustria
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16
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Jang JY, Choi YH, Shin TS, Kim TH, Shin KS, Park HW, Kim YH, Kim H, Choi GJ, Jang KS, Cha B, Kim IS, Myung EJ, Kim JC. Biological Control of Meloidogyne incognita by Aspergillus niger F22 Producing Oxalic Acid. PLoS One 2016; 11:e0156230. [PMID: 27258452 PMCID: PMC4892604 DOI: 10.1371/journal.pone.0156230] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 05/11/2016] [Indexed: 11/27/2022] Open
Abstract
Restricted usage of chemical nematicides has led to development of environmentally safe alternatives. A culture filtrate of Aspergillus niger F22 was highly active against Meloidogyne incognita with marked mortality of second-stage juveniles (J2s) and inhibition of egg hatching. The nematicidal component was identified as oxalic acid by organic acid analysis and gas chromatography-mass spectroscopy (GC-MS). Exposure to 2 mmol/L oxalic acid resulted in 100% juvenile mortality at 1 day after treatment and suppressed egg hatching by 95.6% at 7 days after treatment. Oxalic acid showed similar nematicidal activity against M. hapla, but was not highly toxic to Bursaphelenchus xylophilus. The fungus was incubated on solid medium and dried culture was used for preparation of a wettable powder-type (WP) formulation as an active ingredient. Two WP formulations, F22-WP10 (ai 10%) and oxalic acid-WP8 (ai 8%), were prepared using F22 solid culture and oxalic acid. In a field naturally infested with M. incognita, application of a mixture of F22-WP10 + oxalic acid-WP8 at 1,000- and 500-fold dilutions significantly reduced gall formation on the roots of watermelon plants by 58.8 and 70.7%, respectively, compared to the non-treated control. The disease control efficacy of the mixture of F22-WP10 + oxalic acid-WP8 was significantly higher than that of a chemical nematicide, Sunchungtan (ai 30% fosthiazate). These results suggest that A. niger F22 can be used as a microbial nematicide for the control of root-knot nematode disease.
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Affiliation(s)
- Ja Yeong Jang
- Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, Republic of Korea
- Department of Plant Medicine, Chungbuk National University, Cheongju, Republic of Korea
| | - Yong Ho Choi
- Center for Eco-friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon, Republic of Korea
| | - Teak Soo Shin
- Crop Protection Research Team, Dongbu Advanced Research Institute, Dongbu Farm Hannong Company, Ltd., Nonsan-si, Republic of Korea
| | - Tae Hoon Kim
- Crop Protection Research Team, Dongbu Advanced Research Institute, Dongbu Farm Hannong Company, Ltd., Nonsan-si, Republic of Korea
| | - Kee-Sun Shin
- Biological Resources Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Hae Woong Park
- World Institute of Kimchi, an Annex of Korea Food Research Institute, Gwangju, Republic of Korea
| | - Young Ho Kim
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | - Hun Kim
- Center for Eco-friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon, Republic of Korea
| | - Gyung Ja Choi
- Center for Eco-friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon, Republic of Korea
| | - Kyoung Soo Jang
- Center for Eco-friendly New Materials, Korea Research Institute of Chemical Technology, Daejeon, Republic of Korea
| | - Byeongjin Cha
- Department of Plant Medicine, Chungbuk National University, Cheongju, Republic of Korea
| | - In Seon Kim
- Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, Republic of Korea
| | - Eul Jae Myung
- Crop Protection Research Team, Dongbu Advanced Research Institute, Dongbu Farm Hannong Company, Ltd., Nonsan-si, Republic of Korea
| | - Jin-Cheol Kim
- Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, Republic of Korea
- * E-mail:
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17
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Stepwise flow diagram for the development of formulations of non spore-forming bacteria against foliar pathogens: The case of Lysobacter capsici AZ78. J Biotechnol 2015; 216:56-64. [DOI: 10.1016/j.jbiotec.2015.10.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 09/25/2015] [Accepted: 10/06/2015] [Indexed: 11/21/2022]
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