Plant growth-promoting rhizobacteria(PGPR)are specialized bacterial communities inhabiting the root rhizosphere and the secretion of root exudates helps to,regulate the microbial dynamics and their interactions with t...Plant growth-promoting rhizobacteria(PGPR)are specialized bacterial communities inhabiting the root rhizosphere and the secretion of root exudates helps to,regulate the microbial dynamics and their interactions with the plants.These bacteria viz.,Agrobacterium,Arthobacter,Azospirillum,Bacillus,Burkholderia,Flavobacterium,Pseudomonas,Rhizobium,etc.,play important role in plant growth promotion.In addition,such symbiotic associations of PGPRs in the rhizospheric region also confer protection against several diseases caused by bacterial,fungal and viral pathogens.The biocontrol mechanism utilized by PGPR includes direct and indirect mechanisms direct PGPR mechanisms include the production of antibiotic,siderophore,and hydrolytic enzymes,competition for space and nutrients,and quorum sensing whereas,indirect mechanisms include rhizomicrobiome regulation via.secretion of root exudates,phytostimulation through the release of phytohormones viz.,auxin,cytokinin,gibberellic acid,1-aminocyclopropane-1-carboxylate and induction of systemic resistance through expression of antioxidant defense enzymes viz.,phenylalanine ammonia lyase(PAL),peroxidase(PO),polyphenyloxidases(PPO),superoxide dismutase(SOD),chitinase andβ-glucanases.For the suppression of plant diseases potent bio inoculants can be developed by modulating the rhizomicrobiome through rhizospheric engineering.In addition,understandings of different strategies to improve PGPR strains,their competence,colonization efficiency,persistence and its future implications should also be taken into consideration.展开更多
The application of biostimulants in agriculture represents an environmentally friendly alternative while increasing agricultural production. The aims of the study were to develop solid biostimulants based on five rhiz...The application of biostimulants in agriculture represents an environmentally friendly alternative while increasing agricultural production. The aims of the study were to develop solid biostimulants based on five rhizobacteria native to Benin’s soils and to evaluate their efficacy on the growth and biomass yield of maize under greenhouse conditions on ferrallitic and ferruginous soils. Clay and peat were used as a conservation binder for the preparation of the biostimulants. These binders were used alone or combined in the different formulations with maize flour and sucrose. 10 g of biostimulants were applied at sowing in pots containing five kilograms of sterilised soil. The experimental design was a completely randomised block of 24 treatments with three replicates. The results obtained showed significant improvements (<em>P</em> < 0.001) in height (49.49%), stem diameter (32.7%), leaf area (66.10%), above-ground biomass (97.12%) and below-ground biomass (53.98%) on ferrallitic soil with the application of the clay + <em>Pseudomonas putida</em> biostimulant compared to the control. On the other hand, the use of the peat biostimulant + <em>Pseudomonas syringae</em> was more beneficial for plant growth on ferruginous soil. The height, stem diameter, leaf area, above-ground biomass and below-ground biomass of the plants under the influence of this biostimulant were improved by 83.06%, 44.57%, 102.94%, 86.84% and 42.68%, respectively, compared to the control. Therefore, these results confirm that Rhizobacteria express their potential through biostimulants formulated on maize. The formulated biostimulants can later be used by producers to improve crop productivity for sustainable agriculture.展开更多
Three endemic plants rhizosphere (Astragalus gombo Coss. & Dur., Daucus sahariensis Murb., Ononis angustissima Lam.), were used for actinomycetes isolation. Ninety-three (93) isolates have been screened to evaluat...Three endemic plants rhizosphere (Astragalus gombo Coss. & Dur., Daucus sahariensis Murb., Ononis angustissima Lam.), were used for actinomycetes isolation. Ninety-three (93) isolates have been screened to evaluate their antagonistic properties against phytopathogenic microorganisms and to determine their biocontrol properties against Fusarium culmorum, especially responsible for several cereal diseases like font’s seedlings, rust, and burn of ears. Four (04) isolates (D2, D5, D8, and AST1) have been in vitro tested to determine PGPR effect and biocontrol characters of bread wheat (Triticum aestivum L.), Hidhab (HD) variety cultivated in the Murashigue and Skoog (MS) culture medium. The aim of this study is the evaluation of antagonistic isolates of pathogenic fungi F. culmorum, without and within commercial fungicide (Tebuconazole, 60 g/l) solution. Our results showed clearly that these isolates have a significant effect on seed germination and seedling growth. However, results argue that these actinomycetes isolates show a very interesting activity compared to the commercial fungicide. As a result, these bacteria isolates can be used as biocontrol agents against Fusarium wilt disease of wheat, which have a beneficial effect on growth parameters.展开更多
Garlic is a most important medicinal herb belonging to the family Liliaceae. Both its leaves and bulb are edible. The current study was based on evaluating the growth promoting potential of plant growth promoting rhiz...Garlic is a most important medicinal herb belonging to the family Liliaceae. Both its leaves and bulb are edible. The current study was based on evaluating the growth promoting potential of plant growth promoting rhizobacteria (PGPR) on garlic (Allium sativum L.) growth and biochemical contents. Garlic cloves were inoculated with 3 kinds of PGPRs, Pseudomonas putida (KX574857), Pseudomonas stutzeri (Kx574858) and Bacillus cereus (ATCC14579) at 10<sup>8</sup> cells/mL prior to sowing. Under natural conditions, plants were grown in the net house. The PGPR significantly enhanced % germination, leaf and root growth and their biomass also increased the diameter of bulb and fresh and dry weight. The flavonoids, phenolics, chlorophyll, protein and sugar content were also significantly increased due to PGPR inoculation. The Pseudomonas stutzeri was found most effective for producing longer leaves with moderate sugar, high flavonoids (129%) and phenolics (263%) in bulb over control (Tap). The Pseudomonas putida exhibited a maximum increase in bulb diameter and bulb biomass with maximum phenolics and flavonoid contents.展开更多
The paper first introduces the definition and classification of plant growth promoting rhizobacteria (PGPR), then reviews the research achievements on the mechanism of action of plant growth promoting rhizobacteria,...The paper first introduces the definition and classification of plant growth promoting rhizobacteria (PGPR), then reviews the research achievements on the mechanism of action of plant growth promoting rhizobacteria, including growth pro-moting mechanism and bio-control mechanism, subsequently lists the use of excel-lent plant growth promoting rhizobacteria strains in recent years, especial y Pseu-domonas and Bacil us strains, and final y discusses problems existing in this area and points out issues requiring further exploration, including PGPR screening meth-ods, preservation methods, mechanism of action, in order to commercialize PGPR as soon as possible and practical y realize its application to production.展开更多
The objective of the study was to evaluate the effects of nine plant growth-promoting rhizobacteria (PGPR) alone or in combination on maize seed germination and seedling growth under laboratory and greenhouse conditio...The objective of the study was to evaluate the effects of nine plant growth-promoting rhizobacteria (PGPR) alone or in combination on maize seed germination and seedling growth under laboratory and greenhouse conditions. The germination and growth tests were carried out in square petri dishes and pots. Maize seeds were inoculated with suspension of 108 CFU/ml of rhizobacteria. The experimental device was a random block of 16 treatments with four repetitions. Germination test results showed that seeds inoculated with PGPR including the control induced good germination in the range of 93.75% to 100%. The vigor index and root length of the seeds treated with Bacillus panthothenicus were significantly improved by 76.64% and 58.86%, respectively, while the maximal lengths of the seedlings were obtained with Pseudomonas cichorii with an increase of 118.95%. In greenhouse experience, data demonstrated that Serratia marcescens better improved the leaf area, height and underground biomass, respectively by 58.83%, 108.43%, and 59.16% as compared to the control. The highest fresh aerial biomass and air dry matter was obtained with plants treated only with Pseudomonas putida. These results show the potential to use such rhizobacteria as biofertilizers to improve maize productivity in Benin.展开更多
In this work, local strains of phosphate-solubilizing microorganisms were isolated and identified from the wheat rhizosphere and exogenous acid phosphatase enzymes of locally active phosphate- and potassium-mobilizing...In this work, local strains of phosphate-solubilizing microorganisms were isolated and identified from the wheat rhizosphere and exogenous acid phosphatase enzymes of locally active phosphate- and potassium-mobilizing rhizobacteria belonging to the genera Escherichia, Rahnella, Bacillus, Enterobacter, Pseudomonas, and Pantoea were studied. The efficiency of the physiological properties of rhizobacteria is determined by the production of soluble phosphorus, and the amount of phosphorus depends on the activity and biomass of bacteria that secrete phosphorus. This is done by phosphate solubilizing bacteria, and the habitat ecosystem is enriched with beneficial micronutrients. In these studies, active rhizobacteria activity of acid phosphatase in nutrient liquid was studied at different temperatures. Optimum pH activity index and temperature variability of enzymes were determined. It should be noted that in the most active phosphate-solubilizing strains the maximum enzymatic activity was observed in the culture fluid of R. aquatilis strain 17, which produced 1.086 μmol p-nitrophenol μmol/min/ml. P. agglomerans 22, P. agglomerans 20 and Ps. kilonensis 32 cultures phosphatase activity was 0.143 - 0.680 p-nitrophenol μmol/min/ml. It should be noted that the phosphatase activity of bacteria belonging to the same genus and species was very different from each other. That is, the enzyme activity of Rahnella aquatilis strain 17 was 9 times higher than the enzyme activity of Rahnella aquatilis strain 9. The pH optimum of sour phosphatase enzymes in Rahnella aquatilis strain 16 was 6.0. The optimum temperature of acid phosphatase activity was 45˚C and 50˚C. The reason for this may be that the strains were isolated in different soil and climate conditions. When the acid phosphatase activity of R. aquatilis 3, 9, E. cloacae 8 and P. agglomerans 22 cultures was determined at a temperature of 45˚C, it was observed that the enzyme activity increased by 2 - 4 times. Es. hermannii 1, Ps. kilonensis 26 and B. simplex 28 bacteria acid phosphatase activity was not significantly affected by temperature rise.展开更多
文摘Plant growth-promoting rhizobacteria(PGPR)are specialized bacterial communities inhabiting the root rhizosphere and the secretion of root exudates helps to,regulate the microbial dynamics and their interactions with the plants.These bacteria viz.,Agrobacterium,Arthobacter,Azospirillum,Bacillus,Burkholderia,Flavobacterium,Pseudomonas,Rhizobium,etc.,play important role in plant growth promotion.In addition,such symbiotic associations of PGPRs in the rhizospheric region also confer protection against several diseases caused by bacterial,fungal and viral pathogens.The biocontrol mechanism utilized by PGPR includes direct and indirect mechanisms direct PGPR mechanisms include the production of antibiotic,siderophore,and hydrolytic enzymes,competition for space and nutrients,and quorum sensing whereas,indirect mechanisms include rhizomicrobiome regulation via.secretion of root exudates,phytostimulation through the release of phytohormones viz.,auxin,cytokinin,gibberellic acid,1-aminocyclopropane-1-carboxylate and induction of systemic resistance through expression of antioxidant defense enzymes viz.,phenylalanine ammonia lyase(PAL),peroxidase(PO),polyphenyloxidases(PPO),superoxide dismutase(SOD),chitinase andβ-glucanases.For the suppression of plant diseases potent bio inoculants can be developed by modulating the rhizomicrobiome through rhizospheric engineering.In addition,understandings of different strategies to improve PGPR strains,their competence,colonization efficiency,persistence and its future implications should also be taken into consideration.
文摘The application of biostimulants in agriculture represents an environmentally friendly alternative while increasing agricultural production. The aims of the study were to develop solid biostimulants based on five rhizobacteria native to Benin’s soils and to evaluate their efficacy on the growth and biomass yield of maize under greenhouse conditions on ferrallitic and ferruginous soils. Clay and peat were used as a conservation binder for the preparation of the biostimulants. These binders were used alone or combined in the different formulations with maize flour and sucrose. 10 g of biostimulants were applied at sowing in pots containing five kilograms of sterilised soil. The experimental design was a completely randomised block of 24 treatments with three replicates. The results obtained showed significant improvements (<em>P</em> < 0.001) in height (49.49%), stem diameter (32.7%), leaf area (66.10%), above-ground biomass (97.12%) and below-ground biomass (53.98%) on ferrallitic soil with the application of the clay + <em>Pseudomonas putida</em> biostimulant compared to the control. On the other hand, the use of the peat biostimulant + <em>Pseudomonas syringae</em> was more beneficial for plant growth on ferruginous soil. The height, stem diameter, leaf area, above-ground biomass and below-ground biomass of the plants under the influence of this biostimulant were improved by 83.06%, 44.57%, 102.94%, 86.84% and 42.68%, respectively, compared to the control. Therefore, these results confirm that Rhizobacteria express their potential through biostimulants formulated on maize. The formulated biostimulants can later be used by producers to improve crop productivity for sustainable agriculture.
文摘Three endemic plants rhizosphere (Astragalus gombo Coss. & Dur., Daucus sahariensis Murb., Ononis angustissima Lam.), were used for actinomycetes isolation. Ninety-three (93) isolates have been screened to evaluate their antagonistic properties against phytopathogenic microorganisms and to determine their biocontrol properties against Fusarium culmorum, especially responsible for several cereal diseases like font’s seedlings, rust, and burn of ears. Four (04) isolates (D2, D5, D8, and AST1) have been in vitro tested to determine PGPR effect and biocontrol characters of bread wheat (Triticum aestivum L.), Hidhab (HD) variety cultivated in the Murashigue and Skoog (MS) culture medium. The aim of this study is the evaluation of antagonistic isolates of pathogenic fungi F. culmorum, without and within commercial fungicide (Tebuconazole, 60 g/l) solution. Our results showed clearly that these isolates have a significant effect on seed germination and seedling growth. However, results argue that these actinomycetes isolates show a very interesting activity compared to the commercial fungicide. As a result, these bacteria isolates can be used as biocontrol agents against Fusarium wilt disease of wheat, which have a beneficial effect on growth parameters.
文摘Garlic is a most important medicinal herb belonging to the family Liliaceae. Both its leaves and bulb are edible. The current study was based on evaluating the growth promoting potential of plant growth promoting rhizobacteria (PGPR) on garlic (Allium sativum L.) growth and biochemical contents. Garlic cloves were inoculated with 3 kinds of PGPRs, Pseudomonas putida (KX574857), Pseudomonas stutzeri (Kx574858) and Bacillus cereus (ATCC14579) at 10<sup>8</sup> cells/mL prior to sowing. Under natural conditions, plants were grown in the net house. The PGPR significantly enhanced % germination, leaf and root growth and their biomass also increased the diameter of bulb and fresh and dry weight. The flavonoids, phenolics, chlorophyll, protein and sugar content were also significantly increased due to PGPR inoculation. The Pseudomonas stutzeri was found most effective for producing longer leaves with moderate sugar, high flavonoids (129%) and phenolics (263%) in bulb over control (Tap). The Pseudomonas putida exhibited a maximum increase in bulb diameter and bulb biomass with maximum phenolics and flavonoid contents.
基金Supported by the Science and Technology Project of Nanping Tobacco Company(201203)~~
文摘The paper first introduces the definition and classification of plant growth promoting rhizobacteria (PGPR), then reviews the research achievements on the mechanism of action of plant growth promoting rhizobacteria, including growth pro-moting mechanism and bio-control mechanism, subsequently lists the use of excel-lent plant growth promoting rhizobacteria strains in recent years, especial y Pseu-domonas and Bacil us strains, and final y discusses problems existing in this area and points out issues requiring further exploration, including PGPR screening meth-ods, preservation methods, mechanism of action, in order to commercialize PGPR as soon as possible and practical y realize its application to production.
基金the“Centre National de Specialisation sur le Mais(CNS-Mais),the National Fund for scientific research and Innovation Technology(FNRSIT)for theit financial supports.
文摘The objective of the study was to evaluate the effects of nine plant growth-promoting rhizobacteria (PGPR) alone or in combination on maize seed germination and seedling growth under laboratory and greenhouse conditions. The germination and growth tests were carried out in square petri dishes and pots. Maize seeds were inoculated with suspension of 108 CFU/ml of rhizobacteria. The experimental device was a random block of 16 treatments with four repetitions. Germination test results showed that seeds inoculated with PGPR including the control induced good germination in the range of 93.75% to 100%. The vigor index and root length of the seeds treated with Bacillus panthothenicus were significantly improved by 76.64% and 58.86%, respectively, while the maximal lengths of the seedlings were obtained with Pseudomonas cichorii with an increase of 118.95%. In greenhouse experience, data demonstrated that Serratia marcescens better improved the leaf area, height and underground biomass, respectively by 58.83%, 108.43%, and 59.16% as compared to the control. The highest fresh aerial biomass and air dry matter was obtained with plants treated only with Pseudomonas putida. These results show the potential to use such rhizobacteria as biofertilizers to improve maize productivity in Benin.
文摘In this work, local strains of phosphate-solubilizing microorganisms were isolated and identified from the wheat rhizosphere and exogenous acid phosphatase enzymes of locally active phosphate- and potassium-mobilizing rhizobacteria belonging to the genera Escherichia, Rahnella, Bacillus, Enterobacter, Pseudomonas, and Pantoea were studied. The efficiency of the physiological properties of rhizobacteria is determined by the production of soluble phosphorus, and the amount of phosphorus depends on the activity and biomass of bacteria that secrete phosphorus. This is done by phosphate solubilizing bacteria, and the habitat ecosystem is enriched with beneficial micronutrients. In these studies, active rhizobacteria activity of acid phosphatase in nutrient liquid was studied at different temperatures. Optimum pH activity index and temperature variability of enzymes were determined. It should be noted that in the most active phosphate-solubilizing strains the maximum enzymatic activity was observed in the culture fluid of R. aquatilis strain 17, which produced 1.086 μmol p-nitrophenol μmol/min/ml. P. agglomerans 22, P. agglomerans 20 and Ps. kilonensis 32 cultures phosphatase activity was 0.143 - 0.680 p-nitrophenol μmol/min/ml. It should be noted that the phosphatase activity of bacteria belonging to the same genus and species was very different from each other. That is, the enzyme activity of Rahnella aquatilis strain 17 was 9 times higher than the enzyme activity of Rahnella aquatilis strain 9. The pH optimum of sour phosphatase enzymes in Rahnella aquatilis strain 16 was 6.0. The optimum temperature of acid phosphatase activity was 45˚C and 50˚C. The reason for this may be that the strains were isolated in different soil and climate conditions. When the acid phosphatase activity of R. aquatilis 3, 9, E. cloacae 8 and P. agglomerans 22 cultures was determined at a temperature of 45˚C, it was observed that the enzyme activity increased by 2 - 4 times. Es. hermannii 1, Ps. kilonensis 26 and B. simplex 28 bacteria acid phosphatase activity was not significantly affected by temperature rise.