Inoculation effects on root-colonizing arbuscular mycorrhizal fungal communities spread beyond directly inoculated plants.

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Martina Janoušková

Full Text Available Inoculation with arbuscular mycorrhizal fungi (AMF may improve plant performance at disturbed sites, but inoculation may also suppress root colonization by native AMF and decrease the diversity of the root-colonizing AMF community. This has been shown for the roots of directly inoculated plants, but little is known about the stability of inoculation effects, and to which degree the inoculant and the inoculation-induced changes in AMF community composition spread into newly emerging seedlings that were not in direct contact with the introduced propagules. We addressed this topic in a greenhouse experiment based on the soil and native AMF community of a post-mining site. Plants were cultivated in compartmented pots with substrate containing the native AMF community, where AMF extraradical mycelium radiating from directly inoculated plants was allowed to inoculate neighboring plants. The abundances of the inoculated isolate and of native AMF taxa were monitored in the roots of the directly inoculated plants and the neighboring plants by quantitative real-time PCR. As expected, inoculation suppressed root colonization of the directly inoculated plants by other AMF taxa of the native AMF community and also by native genotypes of the same species as used for inoculation. In the neighboring plants, high abundance of the inoculant and the suppression of native AMF were maintained. Thus, we demonstrate that inoculation effects on native AMF propagate into plants that were not in direct contact with the introduced inoculum, and are therefore likely to persist at the site of inoculation.

Significance of treated agrowaste residue and autochthonous inoculates (Arbuscular mycorrhizal fungi and Bacillus cereus) on bacterial community structure and phytoextraction to remediate soils contaminated with heavy metals.

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Azcón, Rosario; Medina, Almudena; Roldán, Antonio; Biró, Borbála; Vivas, Astrid

2009-04-01

In this study, we analyzed the impact of treatments such as Aspergillus niger-treated sugar beet waste (SB), PO4(3-) fertilization and autochthonous inoculants [arbuscular mycorrhizal (AM) fungi and Bacillus cereus], on the bacterial community structure in a soils contaminated with heavy metals as well as, the effectiveness on plant growth (Trifolium repens). The inoculation with AM fungi in SB amended soil, increased plant growth similarly to PO4(3-) addition, and both treatments matched in P acquisition but bacterial biodiversity estimated by denaturing gradient gel electrophoresis of amplified 16S rDNA sequences, was more stimulated by the presence of the AM fungus than by PO4(3-) fertilization. The SB amendment plus AM inoculation increased the microbial diversity by 233% and also changed (by 215%) the structure of the bacterial community. The microbial inoculants and amendment used favoured plant growth and the phytoextraction process and concomitantly modified bacterial community in the rhizosphere; thus they can be used for remediation. Therefore, the understanding of such microbial ecological aspects is important for phytoremediation and the recovery of contaminated soils.

Effects of inoculation of plant growth-promoting rhizobacteria on metal uptake by Brassica juncea

International Nuclear Information System (INIS)

Wu, S.C.; Cheung, K.C.; Luo, Y.M.; Wong, M.H.

2006-01-01

A greenhouse study was carried out with Brassica juncea to critically evaluate effects of bacterial inoculation on the uptake of heavy metals from Pb-Zn mine tailings by plants. Application of plant growth-promoting rhizobacteria, including nitrogen-fixing bacteria and phosphate and potassium solubilizers, might play an important role in the further development of phytoremediation techniques. The presence of these beneficial bacteria stimulated plant growth and protected the plant from metal toxicity. Inoculation with rhizobacteria had little influence on the metal concentrations in plant tissues, but produced a much larger above-ground biomass and altered metal bioavailability in the soil. As a consequence, higher efficiency of phytoextraction was obtained compared with control treatments. - Rhizobacteria promoted growth above normal biomass, but did not influence plant metal concentrations

Effects of inoculation of plant growth-promoting rhizobacteria on metal uptake by Brassica juncea

Energy Technology Data Exchange (ETDEWEB)

Wu, S.C. [Department of Biology and Croucher Institute for Environmental Sciences, Hong Kong Baptist University, Kowloon Tong, Hong Kong (China); Joint Open Laboratory on Soil and Environment between HKBU and ISSCAS (China); Cheung, K.C. [Department of Biology and Croucher Institute for Environmental Sciences, Hong Kong Baptist University, Kowloon Tong, Hong Kong (China); Joint Open Laboratory on Soil and Environment between HKBU and ISSCAS (China); Luo, Y.M. [Institute of Soil Science, Chinese Academy of Sciences, Nanjing (China); Joint Open Laboratory on Soil and Environment between HKBU and ISSCAS (China); Wong, M.H. [Department of Biology and Croucher Institute for Environmental Sciences, Hong Kong Baptist University, Kowloon Tong, Hong Kong (China) and Joint Open Laboratory on Soil and Environment between HKBU and ISSCAS (China)]. E-mail: mhwong@hkbu.edu.hk

2006-03-15

A greenhouse study was carried out with Brassica juncea to critically evaluate effects of bacterial inoculation on the uptake of heavy metals from Pb-Zn mine tailings by plants. Application of plant growth-promoting rhizobacteria, including nitrogen-fixing bacteria and phosphate and potassium solubilizers, might play an important role in the further development of phytoremediation techniques. The presence of these beneficial bacteria stimulated plant growth and protected the plant from metal toxicity. Inoculation with rhizobacteria had little influence on the metal concentrations in plant tissues, but produced a much larger above-ground biomass and altered metal bioavailability in the soil. As a consequence, higher efficiency of phytoextraction was obtained compared with control treatments. - Rhizobacteria promoted growth above normal biomass, but did not influence plant metal concentrations.

Rhizoctonia solani and Bacterial Inoculants Stimulate Root Exudation of Antifungal Compounds in Lettuce in a Soil-Type Specific Manner

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Saskia Windisch

2017-06-01

Full Text Available Previous studies conducted on a unique field site comprising three contrasting soils (diluvial sand DS, alluvial loam AL, loess loam LL under identical cropping history, demonstrated soil type-dependent differences in biocontrol efficiency against Rhizoctonia solani-induced bottom rot disease in lettuce by two bacterial inoculants (Pseudomonas jessenii RU47 and Serratia plymuthica 3Re-4-18. Disease severity declined in the order DS > AL > LL. These differences were confirmed under controlled conditions, using the same soils in minirhizotron experiments. Gas chromatography-mass spectrometry (GC-MS profiling of rhizosphere soil solutions revealed benzoic and lauric acids as antifungal compounds; previously identified in root exudates of lettuce. Pathogen inoculation and pre-inoculation with bacterial inoculants significantly increased the release of antifungal root exudates in a soil type-specific manner; with the highest absolute levels detected on the least-affected LL soil. Soil type-dependent differences were also recorded for the biocontrol effects of the two bacterial inoculants; showing the highest efficiency after double-inoculation on the AL soil. However, this was associated with a reduction of shoot growth and root hair development and a limited micronutrient status of the host plants. Obviously, disease severity and the expression of biocontrol effects are influenced by soil properties with potential impact on reproducibility of practical applications.

Effects of a dual-purpose bacterial inoculant on the fermentation ...

African Journals Online (AJOL)

Effects of a dual-purpose bacterial inoculant on the fermentation characteristics of high-moisture maize silage and dairy cattle performance. ... Inoculation did not affect the nutritive value or the aerobic stability of the maize silage, but increased the neutral detergent and acid detergent fibre fractions of the silage. However ...

Effects of bacterial inoculation on the fermentation characteristics ...

African Journals Online (AJOL)

DNkosi

2016-05-11

May 11, 2016 ... The chopped forages were treated with or without the bacterial .... packed loosely in an open plastic jar, which was covered with two ..... be because LD inoculant contains enzymes that may be capable of degrading fibre.

Effects of inoculation of biosurfactant-producing Bacillus sp. J119 on plant growth and cadmium uptake in a cadmium-amended soil

International Nuclear Information System (INIS)

Sheng Xiafang; He Linyan; Wang Qingya; Ye Hesong; Jiang Chunyu

2008-01-01

A biosurfactant-producing Bacillus sp. J119 isolated from heavy metal contaminated soils was investigated for its effects on the plant growth-promoting characteristics and heavy metal and antibiotic resistance. A pot experiment was conducted for investigating the capability of the biosurfactant-producing bacterial strain Bacillus sp. J119 to promote the plant growth and cadmium uptake of rape, maize, sudangrass and tomato in soil artificially contaminated with different levels of cadmium (Cd) (0 and 50 mg kg -1 ). The strain was found to exhibit different multiple heavy metal (Pb, Cd, Cu, Ni and Zn) and antibiotic (kanamycin, streptomycin, ampicillin, tetracycline and rifampin) resistance characteristics. The strain had the capacity to produce indole acetic acid (IAA) and siderophores. Cd treatment did not significantly decreased growth of tomato, maize and rape plants, but Cd treatment significantly decreased growth of sudangrass (p -1 , increase in above-ground tissue Cd content varied from 39 to 70% in live bacterium-inoculated plants compared to dead bacterium-inoculated control. In addition, among the inoculated plants, tomato was the greatest Cd accumulator. The bacterial strain was also able to colonize and develop in the rhizosphere soils after root inoculation

Differential growth responses of Brachypodium distachyon genotypes to inoculation with plant growth promoting rhizobacteria.

Science.gov (United States)

do Amaral, Fernanda P; Pankievicz, Vânia C S; Arisi, Ana Carolina M; de Souza, Emanuel M; Pedrosa, Fabio; Stacey, Gary

2016-04-01

Plant growth promoting rhizobacteria (PGPR) can associate and enhance the growth of important crop grasses. However, in most cases, the molecular mechanisms responsible for growth promotion are not known. Such research could benefit by the adoption of a grass model species that showed a positive response to bacterial inoculation and was amenable to genetic and molecular research methods. In this work we inoculated different genotypes of the model grass Brachypodium distachyon with two, well-characterized PGPR bacteria, Azospirillum brasilense and Herbaspirillum seropedicae, and evaluated the growth response. Plants were grown in soil under no nitrogen or with low nitrogen (i.e., 0.5 mM KNO3). A variety of growth parameters (e.g., shoot height, root length, number of lateral roots, fresh and dry weight) were measured 35 days after inoculation. The data indicate that plant genotype plays a very important role in determining the plant response to PGPR inoculation. A positive growth response was observed with only four genotypes grown under no nitrogen and three genotypes tested under low nitrogen. However, in contrast, relatively good root colonization was seen with most genotypes, as measured by drop plate counting and direct, microscopic examination of roots. In particular, the endophytic bacteria H. seropedicae showed strong epiphytic and endophytic colonization of roots.

Arabidopsis seedling flood-inoculation technique: a rapid and reliable assay for studying plant-bacterial interactions

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Uppalapati Srinivasa R

2011-10-01

Full Text Available Abstract Background The Arabidopsis thaliana-Pseudomonas syringae model pathosystem is one of the most widely used systems to understand the mechanisms of microbial pathogenesis and plant innate immunity. Several inoculation methods have been used to study plant-pathogen interactions in this model system. However, none of the methods reported to date are similar to those occurring in nature and amicable to large-scale mutant screens. Results In this study, we developed a rapid and reliable seedling flood-inoculation method based on young Arabidopsis seedlings grown on MS medium. This method has several advantages over conventional soil-grown plant inoculation assays, including a shorter growth and incubation period, ease of inoculation and handling, uniform infection and disease development, requires less growth chamber space and is suitable for high-throughput screens. In this study we demonstrated the efficacy of the Arabidopsis seedling assay to study 1 the virulence factors of P. syringae pv. tomato DC3000, including type III protein secretion system (TTSS and phytotoxin coronatine (COR; 2 the effector-triggered immunity; and 3 Arabidopsis mutants affected in salicylic acid (SA- and pathogen-associated molecular pattern (PAMPs-mediated pathways. Furthermore, we applied this technique to study nonhost resistance (NHR responses in Arabidopsis using nonhost pathogens, such as P. syringae pv. tabaci, pv. glycinea and pv. tomato T1, and confirmed the functional role of FLAGELLIN-SENSING 2 (FLS2 in NHR. Conclusions The Arabidopsis seedling flood-inoculation assay provides a rapid, efficient and economical method for studying Arabidopsis-Pseudomonas interactions with minimal growth chamber space and time. This assay could also provide an excellent system for investigating the virulence mechanisms of P. syringae. Using this method, we demonstrated that FLS2 plays a critical role in conferring NHR against nonhost pathovars of P. syringae, but not to

Effects of water stress, organic amendment and mycorrhizal inoculation on soil microbial community structure and activity during the establishment of two heavy metal-tolerant native plant species.

Science.gov (United States)

Fernández, D A; Roldán, A; Azcón, R; Caravaca, F; Bååth, E

2012-05-01

Our aim was to examine the effect of water stress on plant growth and development of two native plant species (Tetraclinis articulata and Crithmum maritimum) and on microbial community composition and activity in the rhizosphere soil, following the addition of an organic amendment, namely sugar beet residue (SBR), and/or the inoculation with an arbuscular mycorrhizal (AM) fungus, namely Glomus mosseae, in a non-sterile heavy metal-polluted soil. The AM inoculation did not have any significant effect on plant growth of both species. In T. articulata, SBR increased shoot growth, foliar P, total phospholipid fatty acids (PLFA), fungi-related PLFA, AM fungi-related neutral lipid fatty acid, bacterial gram-positive/gram-negative PLFA ratio and the β-glucosidase and dehydrogenase activities. SBR and AM inoculation increased phosphatase activity in T. articulata plants grown under drought conditions. In both plants, there was a synergistic effect between AM inoculation and SBR on mycorrhizal colonisation under drought conditions. In C. maritimum, the increase produced by the SBR on total amounts of PLFA, bacterial gram-positive-related PLFA and bacterial gram-negative-related PLFA was considerably higher under drought conditions. Our results suggest that the effectiveness of the amendment with regard to stimulating microbial communities and plant growth was largely limited by drought, particularly for plant species with a low degree of mycorrhizal colonisation.

Key factors to inoculate Botrytis cinerea in tomato plants

OpenAIRE

Borges,Álefe Vitorino; Saraiva,Rodrigo Moreira; Maffia,Luiz Antonio

2014-01-01

Studies addressing the biological control of Botrytis cinerea have been unsuccessful because of fails in inoculating tomato plants with the pathogen. With the aim of establishing a methodology for inoculation into stems, experiments were designed to assess: i. the aggressiveness of pathogen isolates; ii. the age at which tomato plants should be inoculated; iii. the susceptibility of tissues at different stem heights; iv. the need for a moist chamber after inoculation; and v. the effectiveness...

Inoculation of sugarcane with diazotrophic bacteria

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Nivaldo Schultz

2014-04-01

Full Text Available The sugarcane industry, a strategic crop in Brazil, requires technological improvements in production efficiency to increase the crop energy balance. Among the various currently studied alternatives, inoculation with diazotrophic bacteria proved to be a technology with great potential. In this context, the efficiency of a mixture of bacterial inoculant was evaluated with regard to the agronomic performance and N nutrition of sugarcane. The experiment was carried out on an experimental field of Embrapa Agrobiologia, in Seropédica, Rio de Janeiro, using a randomized block, 2 × 3 factorial design (two varieties and three treatments with four replications, totaling 24 plots. The varieties RB867515 and RB72454 were tested in treatments consisting of: inoculation with diazotrophic bacteria, N-fertilized control with 120 kg ha-1 N and absolute control (no inoculation and no N fertilizer. The inoculum was composed of five strains of five diazotrophic species. The yield, dry matter accumulation, total N in the shoot dry matter and the contribution of N by biological fixation were evaluated, using the natural 15N abundance in non-inoculated sugarcane as reference. The bacterial inoculant increased the stalk yield of variety RB72454 similarly to fertilization with 120 kg ha-1 N in the harvests of plant-cane and first ratoon crops, however the contribution of biological N fixation was unchanged by inoculation, indicating that the benefits of the inoculant in sugarcane may have resulted from plant growth promotion.

Metabolic profiling of two maize (Zea mays L.) inbred lines inoculated with the nitrogen fixing plant-interacting bacteria Herbaspirillum seropedicae and Azospirillum brasilense

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Brusamarello-Santos, Liziane Cristina; Gilard, Françoise; Brulé, Lenaïg; Quilleré, Isabelle; Gourion, Benjamin; Ratet, Pascal; Maltempi de Souza, Emanuel; Lea, Peter J.; Hirel, Bertrand

2017-01-01

Maize roots can be colonized by free-living atmospheric nitrogen (N2)-fixing bacteria (diazotrophs). However, the agronomic potential of non-symbiotic N2-fixation in such an economically important species as maize, has still not been fully exploited. A preliminary approach to improve our understanding of the mechanisms controlling the establishment of such N2-fixing associations has been developed, using two maize inbred lines exhibiting different physiological characteristics. The bacterial-plant interaction has been characterized by means of a metabolomic approach. Two established model strains of Nif+ diazotrophic bacteria, Herbaspirillum seropedicae and Azospirillum brasilense and their Nif- couterparts defficient in nitrogenase activity, were used to evaluate the impact of the bacterial inoculation and of N2 fixation on the root and leaf metabolic profiles. The two N2-fixing bacteria have been used to inoculate two genetically distant maize lines (FV252 and FV2), already characterized for their contrasting physiological properties. Using a well-controlled gnotobiotic experimental system that allows inoculation of maize plants with the two diazotrophs in a N-free medium, we demonstrated that both maize lines were efficiently colonized by the two bacterial species. We also showed that in the early stages of plant development, both bacterial strains were able to reduce acetylene, suggesting that they contain functional nitrogenase activity and are able to efficiently fix atmospheric N2 (Fix+). The metabolomic approach allowed the identification of metabolites in the two maize lines that were representative of the N2 fixing plant-bacterial interaction, these included mannitol and to a lesser extend trehalose and isocitrate. Whilst other metabolites such as asparagine, although only exhibiting a small increase in maize roots following bacterial infection, were specific for the two Fix+ bacterial strains, in comparison to their Fix- counterparts. Moreover, a number

Metabolic profiling of two maize (Zea mays L. inbred lines inoculated with the nitrogen fixing plant-interacting bacteria Herbaspirillum seropedicae and Azospirillum brasilense.

Directory of Open Access Journals (Sweden)

Liziane Cristina Brusamarello-Santos

Full Text Available Maize roots can be colonized by free-living atmospheric nitrogen (N2-fixing bacteria (diazotrophs. However, the agronomic potential of non-symbiotic N2-fixation in such an economically important species as maize, has still not been fully exploited. A preliminary approach to improve our understanding of the mechanisms controlling the establishment of such N2-fixing associations has been developed, using two maize inbred lines exhibiting different physiological characteristics. The bacterial-plant interaction has been characterized by means of a metabolomic approach. Two established model strains of Nif+ diazotrophic bacteria, Herbaspirillum seropedicae and Azospirillum brasilense and their Nif- couterparts defficient in nitrogenase activity, were used to evaluate the impact of the bacterial inoculation and of N2 fixation on the root and leaf metabolic profiles. The two N2-fixing bacteria have been used to inoculate two genetically distant maize lines (FV252 and FV2, already characterized for their contrasting physiological properties. Using a well-controlled gnotobiotic experimental system that allows inoculation of maize plants with the two diazotrophs in a N-free medium, we demonstrated that both maize lines were efficiently colonized by the two bacterial species. We also showed that in the early stages of plant development, both bacterial strains were able to reduce acetylene, suggesting that they contain functional nitrogenase activity and are able to efficiently fix atmospheric N2 (Fix+. The metabolomic approach allowed the identification of metabolites in the two maize lines that were representative of the N2 fixing plant-bacterial interaction, these included mannitol and to a lesser extend trehalose and isocitrate. Whilst other metabolites such as asparagine, although only exhibiting a small increase in maize roots following bacterial infection, were specific for the two Fix+ bacterial strains, in comparison to their Fix- counterparts

Metabolic profiling of two maize (Zea mays L.) inbred lines inoculated with the nitrogen fixing plant-interacting bacteria Herbaspirillum seropedicae and Azospirillum brasilense.

Science.gov (United States)

Brusamarello-Santos, Liziane Cristina; Gilard, Françoise; Brulé, Lenaïg; Quilleré, Isabelle; Gourion, Benjamin; Ratet, Pascal; Maltempi de Souza, Emanuel; Lea, Peter J; Hirel, Bertrand

2017-01-01

Maize roots can be colonized by free-living atmospheric nitrogen (N2)-fixing bacteria (diazotrophs). However, the agronomic potential of non-symbiotic N2-fixation in such an economically important species as maize, has still not been fully exploited. A preliminary approach to improve our understanding of the mechanisms controlling the establishment of such N2-fixing associations has been developed, using two maize inbred lines exhibiting different physiological characteristics. The bacterial-plant interaction has been characterized by means of a metabolomic approach. Two established model strains of Nif+ diazotrophic bacteria, Herbaspirillum seropedicae and Azospirillum brasilense and their Nif- couterparts defficient in nitrogenase activity, were used to evaluate the impact of the bacterial inoculation and of N2 fixation on the root and leaf metabolic profiles. The two N2-fixing bacteria have been used to inoculate two genetically distant maize lines (FV252 and FV2), already characterized for their contrasting physiological properties. Using a well-controlled gnotobiotic experimental system that allows inoculation of maize plants with the two diazotrophs in a N-free medium, we demonstrated that both maize lines were efficiently colonized by the two bacterial species. We also showed that in the early stages of plant development, both bacterial strains were able to reduce acetylene, suggesting that they contain functional nitrogenase activity and are able to efficiently fix atmospheric N2 (Fix+). The metabolomic approach allowed the identification of metabolites in the two maize lines that were representative of the N2 fixing plant-bacterial interaction, these included mannitol and to a lesser extend trehalose and isocitrate. Whilst other metabolites such as asparagine, although only exhibiting a small increase in maize roots following bacterial infection, were specific for the two Fix+ bacterial strains, in comparison to their Fix- counterparts. Moreover, a number

Key factors to inoculate Botrytis cinerea in tomato plants

Directory of Open Access Journals (Sweden)

Álefe Vitorino Borges

2014-09-01

Full Text Available Studies addressing the biological control of Botrytis cinerea have been unsuccessful because of fails in inoculating tomato plants with the pathogen. With the aim of establishing a methodology for inoculation into stems, experiments were designed to assess: i. the aggressiveness of pathogen isolates; ii. the age at which tomato plants should be inoculated; iii. the susceptibility of tissues at different stem heights; iv. the need for a moist chamber after inoculation; and v. the effectiveness of gelatin regarding inoculum adhesion. Infection with an isolate from tomato plants that was previously inoculated into petioles and then re-isolated was successful. An isolate from strawberry plants was also aggressive, although less than that from tomato plants. Tomato plants close to flowering, at 65 days after sowing, and younger, middle and apical stem portions were more susceptible. There was positive correlation between lesion length and sporulation and between lesion length and broken stems. Lesion length and the percentage of sporulation sites were reduced by using a moist chamber and were not affected by adding gelatin to the inoculum suspension. This methodology has been adopted in studies of B. cinerea in tomato plants showing reproducible results. The obtained results may assist researchers who study the gray mold.

Baby bottle steam sterilizers disinfect home nebulizers inoculated with bacterial respiratory pathogens.

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Towle, Dana; Callan, Deborah A; Farrel, Patricia A; Egan, Marie E; Murray, Thomas S

2013-09-01

Contaminated nebulizers are a potential source of bacterial infection but no single method is universally accepted for disinfection. We hypothesized that baby-bottle steam sterilizers effectively disinfect home nebulizers. Home nebulizers were inoculated with the common CF respiratory pathogens methicillin resistant Staphylococcus aureus, Burkholderia cepacia, Haemophilus influenzae, mucoid and non mucoid Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. The nebulizers were swabbed for bacterial growth, treated with either the AVENT (Philips), the NUK Quick & Ready (Gerber) or DRY-POD (Camera Baby) baby bottle steam sterilizer and reswabbed for bacterial growth. All steam sterilizers were effective at disinfecting all home nebulizers. Viable bacteria were not recovered from any inoculated site after steam treatment, under any conditions tested. Steam treatment is an effective disinfection method. Additional studies are needed to confirm whether these results are applicable to the clinical setting. Copyright © 2012 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Growth and cesium uptake responses of Phytolacca americana Linn. and Amaranthus cruentus L. grown on cesium contaminated soil to elevated CO2 or inoculation with a plant growth promoting rhizobacterium Burkholderia sp. D54, or in combination

International Nuclear Information System (INIS)

Tang, Shirong; Liao, Shangqiang; Guo, Junkang; Song, Zhengguo; Wang, Ruigang; Zhou, Xiaomin

2011-01-01

Highlights: ► Elevated CO 2 and microbial inoculation, alone or in combination, significantly promoted growth of P. americana, and A. cruentus. ► Total tissue Cs in plants was significantly increased. ► A. cruentus had higher tissue Cs concentration, Cs transfer factors and concentration ratios than P. americana. ► The two plants had slightly different contents of antioxidant enzymes. ► Combined effects of elevated CO 2 and microbial inoculation can be explored for CO 2 - and microbe-assisted phytoextraction technology. - Abstract: Growth and cesium uptake responses of plants to elevated CO 2 and microbial inoculation, alone or in combination, can be explored for clean-up of contaminated soils, and this induced phytoextraction may be better than the natural process. The present study used open-top chambers to investigate combined effects of Burkholderia sp. D54 inoculation and elevated CO 2 (860 μL L −1 ) on growth and Cs uptake by Phytolacca americana and Amaranthus cruentus grown on soil spiked with various levels of Cs (0–1000 mg kg −1 ). Elevated CO 2 and bacterial inoculation, alone or in combination, significantly increased biomass production with increased magnitude, ranging from 22% to 139% for P. americana, and 14% to 254% for A. cruentus. Total tissue Cs in both plants was significantly greater for bacterial inoculation treatment singly, and combined treatments of bacterial inoculation and elevated CO 2 than for the control treatment in most cases. Regardless of CO 2 concentrations and bacterial inoculation, A. cruentus had higher tissue Cs concentration, Cs transfer factors and concentration ratios than P. americana, but they had slightly different contents of antioxidant enzymes. It is concluded that combined effects of elevated CO 2 and microbial inoculation with regard to plant ability to grow and remove radionuclides from soil can be explored for CO 2 - and microbe-assisted phytoextraction technology.

Soil Type Dependent Rhizosphere Competence and Biocontrol of Two Bacterial Inoculant Strains and Their Effects on the Rhizosphere Microbial Community of Field-Grown Lettuce

Science.gov (United States)

Schreiter, Susanne; Sandmann, Martin; Smalla, Kornelia; Grosch, Rita

2014-01-01

Rhizosphere competence of bacterial inoculants is assumed to be important for successful biocontrol. Knowledge of factors influencing rhizosphere competence under field conditions is largely lacking. The present study is aimed to unravel the effects of soil types on the rhizosphere competence and biocontrol activity of the two inoculant strains Pseudomonas jessenii RU47 and Serratia plymuthica 3Re4-18 in field-grown lettuce in soils inoculated with Rhizoctonia solani AG1-IB or not. Two independent experiments were carried out in 2011 on an experimental plot system with three soil types sharing the same cropping history and weather conditions for more than 10 years. Rifampicin resistant mutants of the inoculants were used to evaluate their colonization in the rhizosphere of lettuce. The rhizosphere bacterial community structure was analyzed by denaturing gradient gel electrophoresis of 16S rRNA gene fragments amplified from total community DNA to get insights into the effects of the inoculants and R. solani on the indigenous rhizosphere bacterial communities. Both inoculants showed a good colonization ability of the rhizosphere of lettuce with more than 106 colony forming units per g root dry mass two weeks after planting. An effect of the soil type on rhizosphere competence was observed for 3Re4-18 but not for RU47. In both experiments a comparable rhizosphere competence was observed and in the presence of the inoculants disease symptoms were either significantly reduced, or at least a non-significant trend was shown. Disease severity was highest in diluvial sand followed by alluvial loam and loess loam suggesting that the soil types differed in their conduciveness for bottom rot disease. Compared to effect of the soil type of the rhizosphere bacterial communities, the effects of the pathogen and the inoculants were less pronounced. The soil types had a surprisingly low influence on rhizosphere competence and biocontrol activity while they significantly affected

Soil type dependent rhizosphere competence and biocontrol of two bacterial inoculant strains and their effects on the rhizosphere microbial community of field-grown lettuce.

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Susanne Schreiter

Full Text Available Rhizosphere competence of bacterial inoculants is assumed to be important for successful biocontrol. Knowledge of factors influencing rhizosphere competence under field conditions is largely lacking. The present study is aimed to unravel the effects of soil types on the rhizosphere competence and biocontrol activity of the two inoculant strains Pseudomonas jessenii RU47 and Serratia plymuthica 3Re4-18 in field-grown lettuce in soils inoculated with Rhizoctonia solani AG1-IB or not. Two independent experiments were carried out in 2011 on an experimental plot system with three soil types sharing the same cropping history and weather conditions for more than 10 years. Rifampicin resistant mutants of the inoculants were used to evaluate their colonization in the rhizosphere of lettuce. The rhizosphere bacterial community structure was analyzed by denaturing gradient gel electrophoresis of 16S rRNA gene fragments amplified from total community DNA to get insights into the effects of the inoculants and R. solani on the indigenous rhizosphere bacterial communities. Both inoculants showed a good colonization ability of the rhizosphere of lettuce with more than 10(6 colony forming units per g root dry mass two weeks after planting. An effect of the soil type on rhizosphere competence was observed for 3Re4-18 but not for RU47. In both experiments a comparable rhizosphere competence was observed and in the presence of the inoculants disease symptoms were either significantly reduced, or at least a non-significant trend was shown. Disease severity was highest in diluvial sand followed by alluvial loam and loess loam suggesting that the soil types differed in their conduciveness for bottom rot disease. Compared to effect of the soil type of the rhizosphere bacterial communities, the effects of the pathogen and the inoculants were less pronounced. The soil types had a surprisingly low influence on rhizosphere competence and biocontrol activity while they

Soil type dependent rhizosphere competence and biocontrol of two bacterial inoculant strains and their effects on the rhizosphere microbial community of field-grown lettuce.

Science.gov (United States)

Schreiter, Susanne; Sandmann, Martin; Smalla, Kornelia; Grosch, Rita

2014-01-01

Rhizosphere competence of bacterial inoculants is assumed to be important for successful biocontrol. Knowledge of factors influencing rhizosphere competence under field conditions is largely lacking. The present study is aimed to unravel the effects of soil types on the rhizosphere competence and biocontrol activity of the two inoculant strains Pseudomonas jessenii RU47 and Serratia plymuthica 3Re4-18 in field-grown lettuce in soils inoculated with Rhizoctonia solani AG1-IB or not. Two independent experiments were carried out in 2011 on an experimental plot system with three soil types sharing the same cropping history and weather conditions for more than 10 years. Rifampicin resistant mutants of the inoculants were used to evaluate their colonization in the rhizosphere of lettuce. The rhizosphere bacterial community structure was analyzed by denaturing gradient gel electrophoresis of 16S rRNA gene fragments amplified from total community DNA to get insights into the effects of the inoculants and R. solani on the indigenous rhizosphere bacterial communities. Both inoculants showed a good colonization ability of the rhizosphere of lettuce with more than 10(6) colony forming units per g root dry mass two weeks after planting. An effect of the soil type on rhizosphere competence was observed for 3Re4-18 but not for RU47. In both experiments a comparable rhizosphere competence was observed and in the presence of the inoculants disease symptoms were either significantly reduced, or at least a non-significant trend was shown. Disease severity was highest in diluvial sand followed by alluvial loam and loess loam suggesting that the soil types differed in their conduciveness for bottom rot disease. Compared to effect of the soil type of the rhizosphere bacterial communities, the effects of the pathogen and the inoculants were less pronounced. The soil types had a surprisingly low influence on rhizosphere competence and biocontrol activity while they significantly affected

Effects of bacterial inoculants and an enzyme on the fermentation ...

African Journals Online (AJOL)

... the effects of bacterial inoculation and cellulase on the fermentation quality of ensiled whole-crop sweet sorghum (WCSS, Sorghum bicolor L. Moench). The WCSS (323 g dry matter (DM)/kg, 251 g water soluble carbohydrates (WSC)/kg DM, 43 g crude protein (CP)/kg DM and 439 g neutral detergent fibre (NDF)/kg DM) ...

Growth and cesium uptake responses of Phytolacca americana Linn. and Amaranthus cruentus L. grown on cesium contaminated soil to elevated CO2 or inoculation with a plant growth promoting rhizobacterium Burkholderia sp. D54, or in combination.

Science.gov (United States)

Tang, Shirong; Liao, Shangqiang; Guo, Junkang; Song, Zhengguo; Wang, Ruigang; Zhou, Xiaomin

2011-12-30

Growth and cesium uptake responses of plants to elevated CO(2) and microbial inoculation, alone or in combination, can be explored for clean-up of contaminated soils, and this induced phytoextraction may be better than the natural process. The present study used open-top chambers to investigate combined effects of Burkholderia sp. D54 inoculation and elevated CO(2) (860 μL L(-1)) on growth and Cs uptake by Phytolacca americana and Amaranthus cruentus grown on soil spiked with various levels of Cs (0-1000 mg kg(-1)). Elevated CO(2) and bacterial inoculation, alone or in combination, significantly increased biomass production with increased magnitude, ranging from 22% to 139% for P. americana, and 14% to 254% for A. cruentus. Total tissue Cs in both plants was significantly greater for bacterial inoculation treatment singly, and combined treatments of bacterial inoculation and elevated CO(2) than for the control treatment in most cases. Regardless of CO(2) concentrations and bacterial inoculation, A. cruentus had higher tissue Cs concentration, Cs transfer factors and concentration ratios than P. americana, but they had slightly different contents of antioxidant enzymes. It is concluded that combined effects of elevated CO(2) and microbial inoculation with regard to plant ability to grow and remove radionuclides from soil can be explored for CO(2)- and microbe-assisted phytoextraction technology. Copyright © 2011 Elsevier B.V. All rights reserved.

Effects of bacterial silage inoculants on whole-crop maize silage ...

African Journals Online (AJOL)

This study evaluated the effects of ensiling whole-crop maize with bacterial inoculants, Lactococcus lactis (LL) and Lactobacillus buchneri (LB), on the fermentation and nutrient digestibility in rams. Whole-crop maize (265 DM g/kg) was ensiled for 90 days in 210 L drums with no additive, or with LL or LB. After three months ...

Effect of bacterial inoculation, plant genotype and developmental stage on root-associated and endophytic bacterial communities in potato (Solanum tuberosum)

NARCIS (Netherlands)

Andreote, F.D.; Rocha, da U.N.; Araujo, W.L.; Azevedo, J.L.; Overbeek, van L.S.

2010-01-01

Beneficial bacteria interact with plants by colonizing the rhizosphere and roots followed by further spread through the inner tissues, resulting in endophytic colonization. The major factors contributing to these interactions are not always well understood for most bacterial and plant species. It is

An optimised method for the extraction of bacterial mRNA from plant roots infected with Escherichia coli O157:H7

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Ashleigh eHolmes

2014-06-01

Full Text Available Analysis of microbial gene expression during host colonisation provides valuable information on the nature of interaction, beneficial or pathogenic, and the adaptive processes involved. Isolation of bacterial mRNA for in planta analysis can be challenging where host nucleic acid may dominate the preparation, or inhibitory compounds affect downstream analysis, e.g. qPCR, microarray or RNA-seq. The goal of this work was to optimise the isolation of bacterial mRNA of food-borne pathogens from living plants. Reported methods for recovery of phytopathogen-infected plant material, using hot phenol extraction and high concentration of bacterial inoculation or large amounts of infected tissues, were found to be inappropriate for plant roots inoculated with Escherichia coli O157:H7. The bacterial RNA yields were too low and increased plant material resulted in a dominance of plant RNA in the sample. To improve the yield of bacterial RNA and reduce the number of plants required, an optimised method was developed which combines bead beating with directed bacterial lysis using SDS and lysozyme. Inhibitory plant compounds, such as phenolics and polysaccharides, were counteracted with the addition of HMW-PEG and CTAB. The new method increased the total yield of bacterial mRNA substantially and allowed assessment of gene expression by qPCR. This method can be applied to other bacterial species associated with plant roots, and also in the wider context of food safety.

Native arbuscular mycorrhizal symbiosis alters foliar bacterial community composition.

Science.gov (United States)

Poosakkannu, Anbu; Nissinen, Riitta; Kytöviita, Minna-Maarit

2017-11-01

The effects of arbuscular mycorrhizal (AM) fungi on plant-associated microbes are poorly known. We tested the hypothesis that colonization by an AM fungus affects microbial species richness and microbial community composition of host plant tissues. We grew the grass, Deschampsia flexuosa in a greenhouse with or without the native AM fungus, Claroideoglomus etunicatum. We divided clonally produced tillers into two parts: one inoculated with AM fungus spores and one without AM fungus inoculation (non-mycorrhizal, NM). We characterized bacterial (16S rRNA gene) and fungal communities (internal transcribed spacer region) in surface-sterilized leaf and root plant compartments. AM fungus inoculation did not affect microbial species richness or diversity indices in leaves or roots, but the AM fungus inoculation significantly affected bacterial community composition in leaves. A total of three OTUs in leaves belonging to the phylum Firmicutes positively responded to the presence of the AM fungus in roots. Another six OTUs belonging to the Proteobacteria (Alpha, Beta, and Gamma) and Bacteroidetes were significantly more abundant in NM plants when compared to AM fungus-inoculated plants. Further, there was a significant correlation between plant dry weight and leaf microbial community compositional shift. Also, there was a significant correlation between leaf bacterial community compositional shift and foliar nitrogen content changes due to AM fungus inoculation. The results suggest that AM fungus colonization in roots has a profound effect on plant physiology that is reflected in leaf bacterial community composition.

The uptake, distribution and translocation of 86Rb in alfalfa plants susceptible and resistant to the bacterial wilt and the effect of Corynebacterium insidiosum upon these processes

International Nuclear Information System (INIS)

Hanker, I.; Kudelova, A.

1981-01-01

Alfalfa (Medicago sativa L.) plants susceptible (S) and resistant (R) to bacterial wilt were fed via roots with a nutrient solution labelled with 86 Rb + , at different times after inoculation with Corynebacterium insidiosum (McCull.) H.L. Jens. The infection did not affect 86 Rb + uptake per plant in the course of a 14-day-period following inoculation; however, it affected its distribution differently in the S- and the R-plants. 86 Rb + uptake significantly decreased due to the infection in the S-plants on the day 49 after inoculation (a 4-h-exposure to 86 Rb + ), with the ions more slowly translocated to the shoots in diseased S-plants than in diseased R-plants. Likely factors causing these effects and their relationship to alfalfa resistance to bacterial wilt are discussed. (author)

Effect of water salinity on wheat inoculated with N fixing bacteria using 15N tracer technique

International Nuclear Information System (INIS)

Al-Sayed, M. A.; Soliman, S. M.; Galal, Y. G. M.; El-Hadidi, E. M.

2012-12-01

A pot experiment was carried out under greenhouse controlled conditions to investigate the effect of water salinity and bacterial inoculation on growth parameters and nutrient uptake by wheat ( Triticum aestivum, L. seda 6). Dry matter yield of shoots was gradually increased with increasing water salinity levels under dual inoculation (Rh + Az). This phenomenon was more pronounced with 6 ds m -1 rather than 3 ds m -1 water salinity level. This holds true with all inoculation treatments. Similar trend was noticed with root dry matter yield. N uptake by shoots was positively affected by water salinity levels under bacterial inoculation especially the dual treatments where N uptake tended to increase with increasing water salinity levels. N uptake by roots was severely affected by increasing water salinity levels as compared to fresh water treatment. N uptake by shoots was enhanced by inoculation under different water salinity levels as compared to the un inoculated treatment. Nitrogen uptake roots was dramatically affected by inoculation. It was only increased by inoculation when plants were irrigated with fresh water. Portions of Ndff were frequently affected by both water salinity levels and microbial inoculation. wheat plant as representative of cereal crops was more dependent on the portion of nitrogen up taken from fertilizer rather than those fixed from the air. Therefore, the plant-bacteria association was not efficient enough. Inoculated treatments compensated considerable amounts of its N demand from air beside those derived from fertilizer, therefore the remained N from fertilizer in soil was higher than those of un inoculated control which is more dependable on Ndff as well as Ndf s. 1 5N recovery by wheat plants was enhanced by bacterial inoculation as well as water salinity levels did. (Author)

Histochemical response of `Grande naine' plants inoculated with M. fijiensis and Bacillus pumilus CCIBP-C5 cell free filtrate

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Eilyn Mena

2015-04-01

Full Text Available In recent years, interest has won biocontrol Mycosphaerella fijiensis with the use of microorganisms or their products. Nevertheless, the knowledge of the biochemical events involved in Musa- M. fijiensis-microorganism interaction, is still limited. The objective was to determine the histochemical response of `Grande naine' (Musa AAA plants inoculated or not with the pathogen in the presence of culture filtrate of Bacillus pumilus CCIBP-C5. For this, techniques that allow visualization of callose, superoxide anion, lignin and phenolic compounds in the early days post inoculation (dpi were used. As a result, at 6 dpi callose deposition were observed within the stomata in plants where the culture filtrate was applied regardless of the presence or absence of the pathogen. Furthermore, a blue halo was observed around stomas, indicative of the presence of superoxide anion. It was not possible to detect accumulation of lignin or phenolic compounds with the technique used. It was demonstrated the accumulation of biochemical compounds related to defense response of `Grande naine' plants to pathogen infection. Furthermore, it was shown that the plant responds in early infection with the use of bacterial culture filtrates. These results demonstrate the possible mechanism of induction of defense response in plants of Musa sp. in the presence of bacterial culture filtrate. Key words: Black Sigatoka, callose, lignin, phenols, superoxide anion

Growth and cesium uptake responses of Phytolacca americana Linn. and Amaranthus cruentus L. grown on cesium contaminated soil to elevated CO{sub 2} or inoculation with a plant growth promoting rhizobacterium Burkholderia sp. D54, or in combination

Energy Technology Data Exchange (ETDEWEB)

Tang, Shirong, E-mail: tangshir@hotmail.com [Centre for Research in Ecotoxicology and Environmental Remediation, Agro-Environmental Protection Institute, Ministry of Agriculture, Tianjin 300191 (China); Key Laboratory of Production Environment and Agro-product Safety of Ministry of Agriculture, Tianjin (China); Liao, Shangqiang; Guo, Junkang; Song, Zhengguo; Wang, Ruigang [Centre for Research in Ecotoxicology and Environmental Remediation, Agro-Environmental Protection Institute, Ministry of Agriculture, Tianjin 300191 (China); Key Laboratory of Production Environment and Agro-product Safety of Ministry of Agriculture, Tianjin (China); Zhou, Xiaomin [Plant Science Department, McGill University, Macdonald Campus, 21111 Lakeshore Road, Ste. Anne de Bellevue, Quebec, Canada H9X 3V9 (Canada)

2011-12-30

Highlights: Black-Right-Pointing-Pointer Elevated CO{sub 2} and microbial inoculation, alone or in combination, significantly promoted growth of P. americana, and A. cruentus. Black-Right-Pointing-Pointer Total tissue Cs in plants was significantly increased. Black-Right-Pointing-Pointer A. cruentus had higher tissue Cs concentration, Cs transfer factors and concentration ratios than P. americana. Black-Right-Pointing-Pointer The two plants had slightly different contents of antioxidant enzymes. Black-Right-Pointing-Pointer Combined effects of elevated CO{sub 2} and microbial inoculation can be explored for CO{sub 2}- and microbe-assisted phytoextraction technology. - Abstract: Growth and cesium uptake responses of plants to elevated CO{sub 2} and microbial inoculation, alone or in combination, can be explored for clean-up of contaminated soils, and this induced phytoextraction may be better than the natural process. The present study used open-top chambers to investigate combined effects of Burkholderia sp. D54 inoculation and elevated CO{sub 2} (860 {mu}L L{sup -1}) on growth and Cs uptake by Phytolacca americana and Amaranthus cruentus grown on soil spiked with various levels of Cs (0-1000 mg kg{sup -1}). Elevated CO{sub 2} and bacterial inoculation, alone or in combination, significantly increased biomass production with increased magnitude, ranging from 22% to 139% for P. americana, and 14% to 254% for A. cruentus. Total tissue Cs in both plants was significantly greater for bacterial inoculation treatment singly, and combined treatments of bacterial inoculation and elevated CO{sub 2} than for the control treatment in most cases. Regardless of CO{sub 2} concentrations and bacterial inoculation, A. cruentus had higher tissue Cs concentration, Cs transfer factors and concentration ratios than P. americana, but they had slightly different contents of antioxidant enzymes. It is concluded that combined effects of elevated CO{sub 2} and microbial inoculation with

effects of rhizobuim leguminosarum inoculation on the growth and ...

African Journals Online (AJOL)

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beneficial symbiotic microorganisms into the plant. Rhizosphere ... Rhizobium strains in the yeast manitol broth were ... inoculants contained sixteen (16) colonies of Rhizobium leguminosarum bacterial cells per milliliter (ml) of the yeast ...

Promotion of arsenic phytoextraction efficiency in the fern Pteris vittata by the inoculation of As-resistant bacteria: a soil bioremediation perspective.

Science.gov (United States)

Lampis, Silvia; Santi, Chiara; Ciurli, Adriana; Andreolli, Marco; Vallini, Giovanni

2015-01-01

A greenhouse pot experiment was carried out to evaluate the efficiency of arsenic phytoextraction by the fern Pteris vittata growing in arsenic-contaminated soil, with or without the addition of selected rhizobacteria isolated from the polluted site. The bacterial strains were selected for arsenic resistance, the ability to reduce arsenate to arsenite, and the ability to promote plant growth. P. vittata plants were cultivated for 4 months in a contaminated substrate consisting of arsenopyrite cinders and mature compost. Four different experimental conditions were tested: (i) non-inoculated plants; (ii) plants inoculated with the siderophore-producing and arsenate-reducing bacteria Pseudomonas sp. P1III2 and Delftia sp. P2III5 (A); (iii) plants inoculated with the siderophore and indoleacetic acid-producing bacteria Bacillus sp. MPV12, Variovorax sp. P4III4, and Pseudoxanthomonas sp. P4V6 (B), and (iv) plants inoculated with all five bacterial strains (AB). The presence of growth-promoting rhizobacteria increased plant biomass by up to 45% and increased As removal efficiency from 13% without bacteria to 35% in the presence of the mixed inoculum. Molecular analysis confirmed the persistence of the introduced bacterial strains in the soil and resulted in a significant impact on the structure of the bacterial community.

Promotion of arsenic phytoextraction efficiency in the fern Pteris vittata by the inoculation of As-resistant bacteria: a soil bioremediation perspective

Science.gov (United States)

Lampis, Silvia; Santi, Chiara; Ciurli, Adriana; Andreolli, Marco; Vallini, Giovanni

2015-01-01

A greenhouse pot experiment was carried out to evaluate the efficiency of arsenic phytoextraction by the fern Pteris vittata growing in arsenic-contaminated soil, with or without the addition of selected rhizobacteria isolated from the polluted site. The bacterial strains were selected for arsenic resistance, the ability to reduce arsenate to arsenite, and the ability to promote plant growth. P. vittata plants were cultivated for 4 months in a contaminated substrate consisting of arsenopyrite cinders and mature compost. Four different experimental conditions were tested: (i) non-inoculated plants; (ii) plants inoculated with the siderophore-producing and arsenate-reducing bacteria Pseudomonas sp. P1III2 and Delftia sp. P2III5 (A); (iii) plants inoculated with the siderophore and indoleacetic acid-producing bacteria Bacillus sp. MPV12, Variovorax sp. P4III4, and Pseudoxanthomonas sp. P4V6 (B), and (iv) plants inoculated with all five bacterial strains (AB). The presence of growth-promoting rhizobacteria increased plant biomass by up to 45% and increased As removal efficiency from 13% without bacteria to 35% in the presence of the mixed inoculum. Molecular analysis confirmed the persistence of the introduced bacterial strains in the soil and resulted in a significant impact on the structure of the bacterial community. PMID:25741356

Promotion of arsenic phytoextraction efficiency in the fern Pteris vittata by the inoculation of As-resistant bacteria: a soil bioremediation perspective.

Directory of Open Access Journals (Sweden)

Silvia eLampis

2015-02-01

Full Text Available A greenhouse pot experiment was carried out to evaluate the efficiency of arsenic phytoextraction by the fern Pteris vittata growing in arsenic-contaminated soil, with or without the addition of selected rhizobacteria isolated from the polluted site. The bacterial strains were selected for arsenic resistance, the ability to reduce arsenate to arsenite, and the ability to promote plant growth. P. vittata plants were cultivated for 4 months in a contaminated substrate consisting of arsenopyrite cinders and mature compost. Four different experimental conditions were tested: i non-inoculated plants; ii plants inoculated with the siderophore-producing and arsenate-reducing bacteria Pseudomonas sp. P1III2 and Delftia sp. P2III5 (A; iii plants inoculated with the siderophore and indoleacetic acid-producing bacteria Bacillus sp. MPV12, Variovorax sp. P4III4 and Pseudoxanthomonas sp. P4V6 (B, and iv plants inoculated with all five bacterial strains (AB. The presence of growth-promoting rhizobacteria increased plant biomass by up to 45% and increased As removal efficiency from 13% without bacteria to 35% in the presence of the mixed inoculum. Molecular analysis confirmed the persistence of the introduced bacterial strains in the soil and resulted in a significant impact on the structure of the bacterial community.

Intensity of Ground Cover Crop Arachis pintoi, Rhizobium Inoculation and Phosphorus Application and Their Effects on Field Growth and Nutrient Status of Cocoa Plants

Directory of Open Access Journals (Sweden)

John Bako Baon

2006-08-01

Full Text Available Arachis pintoiis potentially as a cover crop for cocoa (Theobroma cacaoL. farm, however information regarding its effect on the growth of cocoa plants in the field is very limited. The objective of this experiment is to investigate the combined influence of ground cover crop A. pintoi, rhizobial bacterial inoculation and phosphorus (P fertilizer on the growth of cocoa in the field and nutrient status. This experiment laid out in split-split plot design consisted of three levels of cover crop (without, A. pintoiand Calopogonium caeruleum, two levels of rhizobium inoculation (not inoculated and inoculated and two levels of phosphorus application (no P added and P added. The results showed that in field condition the presence of A. pintoias cover crop did not affect the growth of cocoa. On the other hand, C. caeruleumas cover crop tended to restrict cocoa growth compared to A. pintoi. Application of P increased leaf number of cocoa plant. Biomass production of A. pintoiwas 40% higher than C. caeruleum. Soil organic carbon and nitrogen contents were not affected by ground cover crops, though higher value (0.235% N and 1.63% organic C was obtained from combined treatments of inoculation and P addition or neither inoculation nor P addition. In the case of no rhizobium inoculation, soil N content in cocoa farm with A. pintoicover crop was lower than that of without cover crop or with C. caeruleum. Cover crop increased plant N content when there was no inoculation, on the other hand rhizobium inoculation decreased N content of cocoa tissue. Tissue P content of cocoa plant was not influenced by A. Pintoicover crop or by rhizobium inoculation, except that the P tissue content of cocoa was 28% higher when the cover crop was C. caeruleumand inoculated. Key words : Arachis pintoi, Theobroma cacao, Calopogonium caeruleum, rhizobium, nitrogen, phosphorus.

Evaluating phytoextraction efficiency of two high-biomass crops after soil amendment and inoculation with rhizobacterial strains.

Science.gov (United States)

Vanessa, Álvarez-López; Ángeles, Prieto-Fernández; Sergio, Roiloa; Beatriz, Rodríguez-Garrido; Rolf, Herzig; Markus, Puschenreiter; Susan, Kidd Petra

2017-03-01

We evaluated the effect of compost amendment and/or bacterial inoculants on the growth and metal accumulation of Salix caprea (clone BOKU 01 AT-004) and Nicotiana tabacum (in vitro-bred clone NBCu10-8). Soil was collected from an abandoned Pb/Zn mine and rhizobacterial inoculants were previously isolated from plants growing at the same site. Plants were grown in untreated or compost-amended (5% w/w) soil and were inoculated with five rhizobacterial strains. Non-inoculated plants were also established as a control. Compost addition increased the shoot DW yield of N. tabacum but not S. caprea, while it decreased soil metal availability and lowered shoot Cd/Zn concentrations in tobacco plants. Compost amendment enhanced the shoot Cd/Zn removal due to the growth promotion of N. tabacum or to the increase in metal concentration in S. caprea leaves. Bacterial inoculants increased photosynthetic efficiency (particularly in N. tabacum) and sometimes modified soil metal availability, but this did not lead to a significant increase in Cd/Zn removal. Compost amendment was more effective in improving the Cd and Zn phytoextraction efficiency than bioaugmentation.

DEVELOPMENT OF PIGEON PEA INOCULATED WITH RHIZOBIUM ISOLATED FROM COWPEA TRAP HOST PLANTS

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SALOMÃO LIMA GUIMARÃES

2016-01-01

Full Text Available Pigeon pea is an important protein source grown in several tropical and sub - tropical countries, and is considered a multi - purpose plant that is resistant to the conditions of the Brazilian Cerrado. Among the possible uses for cowpea, its use as a green manure, increasing soil nitrogen content through the association with diazotrophic bacteria, generically known as rhizobia, is noteworthy. The present work aimed to evaluate the efficiency of Rhizobium strains isolated from cowpea plants in the development of pigeon peas cultured in Red Latosol. The experiment was conducted in a greenhouse, using a completely randomized design with seven treatments and four replications. Treatments consisted of inoculation with four Rhizobium strains (MT8, MT15, MT16, and MT23 and one commercial inoculant comprising Bradyrhizobium spp. strains BR 2801 and BR 2003. There were two controls, one absolute (without inoculation or nitrogen fertilization and the other with nitrogen fertilization. Each experimental plot consisted of an 8 - dm 3 vase containing three plants. Analyzed variables included plant height, SPAD index, number and dry weight of nodules, and shoot and root dry masses. Pigeon peas responded significantly to inoculation treatment, since all the plants inoculated with Rhizobium strains isolated from cowpea strains showed results similar to plants in the nitrogen control and commercial inoculant treatments. This demonstrates a favorable plant – bacteria interaction, which can be utilized as an alternative nitrogen source for pigeon peas.

Comparative analysis of tannery-effluent contaminated soil and mixed culture bacterial inoculation on helianthus annuus L. growth

International Nuclear Information System (INIS)

Yasin, M.; Faisal, M.

2012-01-01

Here we reported the effect of four strains Bacillus pumilus-CrK08, Cellulosimicrobium cellulans-CrK16, Exiguobacterium-CrK19 and Bacillus cereus-CrK20 and tannery contaminated soil on Helianthus annuus L. var Hysun-33 growth parameters. Plants growing in tannery effluent contaminated soil have shown slowed leaf growth, reduced shoot length, burning of leaf margins and tips compared to plants growing in normal garden soil. The inoculated plants had shown overall increase in root length (15%), shoot length (33%) and fresh weight shoot (135%) compared to un-inoculated plants growing in stress conditions. Plants growing in tannery contaminated soil have shown increase in soluble proteins contents (9%), acid phosphatase activity (200%), peroxidase activity (203%) and decrease in chlorophyll a (39%), chlorophyll b (23%) and carotenoids contents (28%) compare to plants growing in normal control soil. Inoculated plants grown in contaminated soil have shown an increased in peroxidase activity, soluble proteins contents, acid phosphatase activity, chlorophyll a, b and carotenoid contents compare to respective un-inoculated plants. (author)

Ethylene emission and PR protein synthesis in ACC deaminase producing Methylobacterium spp. inoculated tomato plants (Lycopersicon esculentum Mill.) challenged with Ralstonia solanacearum under greenhouse conditions.

Science.gov (United States)

Yim, Woojong; Seshadri, Sundaram; Kim, Kiyoon; Lee, Gillseung; Sa, Tongmin

2013-06-01

Bacteria of genus Methylobacterium have been found to promote plant growth and regulate the level of ethylene in crop plants. This work is aimed to test the induction of defense responses in tomato against bacterial wilt by stress ethylene level reduction mediated by the ACC deaminase activity of Methylobacterium strains. Under greenhouse conditions, the disease index value in Methylobacterium sp. inoculated tomato plants was lower than control plants. Plants treated with Methylobacterium sp. challenge inoculated with Ralstonia solanacearum (RS) showed significantly reduced disease symptoms and lowered ethylene emission under greenhouse condition. The ACC and ACO (1-aminocyclopropane-1-carboxylate oxidase) accumulation in tomato leaves were significantly reduced with Methylobacterium strains inoculation. While ACC oxidase gene expression was found higher in plants treated with R. solanacearum than Methylobacterium sp. treatment, PR proteins related to induced systemic resistance like β-1,3-glucanase, PAL, PO and PPO were increased in Methylobacterium sp. inoculated plants. A significant increase in β-1,3-glucanase and PAL gene expression was found in all the Methylobacterium spp. treatments compared to the R. solanacearum treatment. This study confirms the activity of Methylobacterium sp. in increasing the defense enzymes by modulating the ethylene biosynthesis pathway and suggests the use of methylotrophic bacteria as potential biocontrol agents in tomato cultivation. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

PLANT GROWTH-PROMOTING MICROBIAL INOCULANT FOR Schizolobium parahyba pv. parahyba

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Priscila Jane Romano de Oliveira Gonçalves

2015-08-01

Full Text Available ABSTRACTSchizolobium parahyba pv. amazonicum (Huber ex Ducke Barneby (paricá occurs naturally in the Amazon and is significant commercial importance due to its rapid growth and excellent performance on cropping systems. The aim of this paper was to evaluate a microbial inoculants such as arbuscular mycorrhiza fungi (AMF and Rhizobium sp. that promote plant growth. The inocula was 10 g of root colonized and spores of Glomus clarum and/or 1 mL of cell suspension (107 CFU/mL of Rhizobium sp. and/or 100 g of chemical fertilizer NPK 20-05-20 per planting hole. The experimental design was complete randomized blocks with five replications and eight treatments (n = 800. Plant height, stem diameter and plant survival were measured. The results were tested for normality and homogeneity of variances and analyzed by ANOVA and Tukey test (p < 0.05. Rhizobium sp and AM fungi showed no effect on plant growth. Environmental factors probably influenced the effectiveness of symbiosis of both microorganisms and plant growth. The chemical fertilizer increased S. parahyba growth. During the first 120 days plants suffered with drought and frost, and at 180 days plants inoculated with microorganism plus chemical fertilizer showed higher survival when compared with control. The results showed that the microbial inoculants used showed an important role on plant survival after high stress conditions, but not in plant growth. Also was concluded that the planting time should be between November to December to avoid the presence of young plants during winter time that is dry and cold.

Inoculation effects on root-colonizing arbuscular mycorrhizal fungal communities spread beyond directly inoculated plants

Czech Academy of Sciences Publication Activity Database

Janoušková, Martina; Krak, Karol; Vosátka, Miroslav; Püschel, David; Štorchová, Helena

2017-01-01

Roč. 12, č. 7 (2017), s. 1-21, č. článku e0181525. E-ISSN 1932-6203 R&D Projects: GA MŠk(CZ) LH14285 Institutional support: RVO:67985939 ; RVO:61389030 Keywords : inoculation * arbuscular mycorrhiza * community Subject RIV: EH - Ecology, Behaviour; EH - Ecology, Behaviour (UEB-Q) OBOR OECD: Plant sciences, botany; Plant sciences, botany (UEB-Q) Impact factor: 2.806, year: 2016

Bacterial and fungal communities of wilted Italian ryegrass silage inoculated with and without Lactobacillus rhamnosus or Lactobacillus buchneri.

Science.gov (United States)

Li, Y; Nishino, N

2011-04-01

To understand the effects of lactic acid bacteria (LAB) inoculation on fermentation products, aerobic stability and microbial communities of silage. Wilted Italian ryegrass was stored in laboratory silos with and without inoculation of Lactobacillus rhamnosus and Lactobacillus buchneri. The silos were opened after 14, 56 and 120 days and then subjected to aerobic deterioration for 7 days. Intensive alcoholic fermentation was found in untreated silage; the sum of ethanol and 2,3-butanediol content at day 14 was about 7 times higher than that of lactic and volatile fatty acids. Alcoholic fermentation was suppressed by L. rhamnosus and L. buchneri inoculation and lactic acid and acetic acid became the dominant fermentation products, respectively. Silages were deteriorated in untreated and L. rhamnosus-inoculated silages, whereas no spoilage was found in L. buchneri-inoculated silage. Enterobacteria such as Erwinia persicina, Pantoea agglomerans and Rahnella aquatilis were detected in untreated silage, whereas some of these bacteria disappeared or became faint with L. rhamnosus treatment. When silage was deteriorated, Lactobacillus brevis and Bacillus pumilus were observed in untreated and L. rhamnosus-inoculated communities, respectively. The inoculated LAB species was detectable in addition to untreated bacterial communities. Saccharomyces cerevisiae and Pichia anomala were the main fungi in untreated and L. rhamnosus-inoculated silages; however, P. anomala was not visibly seen in L. buchneri-inoculated silage either at silo opening or after exposure to air. Inoculation with L. rhamnosus can suppress alcoholic fermentation of wilted grass silage with elimination of enterobacteria at the beginning of fermentation. Addition of L. buchneri may improve aerobic stability, with distinct inhibitory effect observed on P. anomala after silo opening. Bacterial and fungal community analyses help us to understand how inoculated LAB can function to improve the fermentation and

Bacterial endophytes enhance phytostabilization in soils contaminated with uranium and lead.

Science.gov (United States)

Ahsan, Muhammad Tayyab; Najam-Ul-Haq, Muhammad; Idrees, Muhammad; Ullah, Inayat; Afzal, Muhammad

2017-10-03

The combined use of plants and bacteria is a promising approach for the remediation of polluted soil. In the current study, the potential of bacterial endophytes in partnership with Leptochloa fusca (L.) Kunth was evaluated for the remediation of uranium (U)- and lead (Pb)-contaminated soil. L. fusca was vegetated in contaminated soil and inoculated with three different endophytic bacterial strains, Pantoea stewartii ASI11, Enterobacter sp. HU38, and Microbacterium arborescens HU33, individually as well as in combination. The results showed that the L. fusca can grow in the contaminated soil. Bacterial inoculation improved plant growth and phytoremediation capacity: this manifested in the form of a 22-51% increase in root length, 25-62% increase in shoot height, 10-21% increase in chlorophyll content, and 17-59% more plant biomass in U- and Pb-contaminated soils as compared to plants without bacterial inoculation. Although L. fusca plants showed potential to accumulate U and Pb in their root and shoot on their own, bacterial consortia further enhanced metal uptake capacity by 53-88% for U and 58-97% for Pb. Our results indicate that the combination of L. fusca and endophytic bacterial consortia can effectively be used for the phytostabilization of both U- and Pb-contaminated soils.

Effect of organic acids production and bacterial community on the possible mechanism of phosphorus solubilization during composting with enriched phosphate-solubilizing bacteria inoculation.

Science.gov (United States)

Wei, Yuquan; Zhao, Yue; Shi, Mingzi; Cao, Zhenyu; Lu, Qian; Yang, Tianxue; Fan, Yuying; Wei, Zimin

2018-01-01

Enriched phosphate-solubilizing bacteria (PSB) agent were acquired by domesticated cultivation, and inoculated into kitchen waste composting in different stages. The effect of different treatments on organic acids production, tricalcium phosphate (TCP) solubilization and their relationship with bacterial community were investigated during composting. Our results pointed out that inoculation affected pH, total acidity and the production of oxalic, lactic, citric, succinic, acetic and formic acids. We also found a strong advantage in the solubilization of TCP and phosphorus (P) availability for PSB inoculation especially in the cooling stage. Redundancy analysis and structural equation models demonstrated inoculation by different methods changed the correlation of the bacterial community composition with P fractions as well as organic acids, and strengthened the cooperative function related to P transformation among species during composting. Finally, we proposed a possible mechanism of P solubilization with enriched PSB inoculation, which was induced by bacterial community and organic acids production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sewage sludge amendment and inoculation with plant-parasitic nematodes do not facilitate the internalization of Salmonella Typhimurium LT2 in lettuce plants.

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Fornefeld, Eva; Baklawa, Mohamed; Hallmann, Johannes; Schikora, Adam; Smalla, Kornelia

2018-05-01

Contamination of fruits and vegetables with Salmonella is a serious threat to human health. In order to prevent possible contaminations of fresh produce it is necessary to identify the contributing ecological factors. In this study we investigated whether the addition of sewage sludge or the presence of plant-parasitic nematodes foster the internalization of Salmonella enterica serovar Typhimurium LT2 into lettuce plants, posing a potential threat for human health. Greenhouse experiments were conducted to investigate whether the amendment of sewage sludge to soil or the presence of plant-parasitic nematodes Meloidogyne hapla or Pratylenchus crenatus promote the internalization of S. Typhimurium LT2 from soil into the edible part of lettuce plants. Unexpectedly, numbers of cultivable S. Typhimurium LT2 decreased faster in soil with sewage sludge than in control soil but not in root samples. Denaturing gradient gel electrophoresis analysis revealed shifts of the soil bacterial communities in response to sewage sludge amendment and time. Infection and proliferation of nematodes inside plant roots were observed but did not influence the number of cultivable S. Typhimurium LT2 in the root samples or in soil. S. Typhimurium LT2 was not detected in the leaf samples 21 and 49 days after inoculation. The results indicate that addition of sewage sludge, M. hapla or P. crenatus to soil inoculated with S. Typhimurium LT2 did not result in an improved survival in soil or internalization of lettuce plants. Copyright © 2017. Published by Elsevier Ltd.

Soil inoculation method determines the strength of plant-soil interactions

NARCIS (Netherlands)

Voorde, van de T.F.J.; Ruijten, M.; Putten, van der W.H.; Bezemer, T.M.

2012-01-01

There is increasing evidence that interactions between plants and biotic components of the soil influence plant productivity and plant community composition. Many plant–soil feedback experiments start from inoculating relatively small amounts of natural soil to sterilized bulk soil. These soil

Effect of exogenous inoculants on enhancing oil recovery and indigenous bacterial community dynamics in long-term field pilot of low permeability reservoir.

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Li, Jing; Xue, Shuwen; He, Chunqiu; Qi, Huixia; Chen, Fulin; Ma, Yanling

2018-03-20

Pseudomonas aeruginosa DN1 strain and Bacillus subtilis QHQ110 strain were chosen as rhamnolipid and lipopeptide producer respectively, to evaluate the efficiency of exogenous inoculants on enhancing oil recovery (EOR) and to explore the relationship between injected bacteria and indigenous bacterial community dynamics in long-term filed pilot of Hujianshan low permeability water-flooded reservoir for 26 months. Core-flooding tests showed that the oil displacement efficiency increased by 18.46% with addition of exogenous consortia. Bacterial community dynamics using quantitative PCR and high-throughput sequencing revealed that the exogenous inoculants survived and could live together with indigenous bacterial populations. They gradually became the dominant community after the initial activation, while their comparative advantage weakened continually after 3 months of the first injection. The bacterial populations did not exert an observable change in the process of the second injection of exogenous inoculants. On account of facilitating oil emulsification and accelerating bacterial growth with oil as the carbon source by the injection of exogenous consortia, γ-proteobacteria was finally the prominent bacterial community at class level varying from 25.55 to 32.67%, and the dominant bacterial populations were increased by 2-3 orders of magnitude during the whole processes. The content of organic acids and rhamnolipids in reservoir were promoted with the change of bacterial community diversity, respectively. Cumulative oil increments reached 26,190 barrels for 13 months after the first injection, and 55,947 barrels of oil had been accumulated in all of A20 wells block through two rounds of bacterial consortia injection. The performance of EOR has a cumulative improvement by the injection of exogenous inoculants without observable inhibitory effect on the indigenous bacterial populations, demonstrating the application potential in low permeability water

Hydrogen Peroxide- and Nitric Oxide-mediated Disease Control of Bacterial Wilt in Tomato Plants

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Jeum Kyu Hong

2013-12-01

Full Text Available Reactive oxygen species (ROS generation in tomato plants by Ralstonia solanacearum infection and the role of hydrogen peroxide (H₂O₂ and nitric oxide in tomato bacterial wilt control were demonstrated. During disease development of tomato bacterial wilt, accumulation of superoxide anion (O₂− and H₂O₂ was observed and lipid peroxidation also occurred in the tomato leaf tissues. High doses of H₂O₂and sodium nitroprusside (SNP nitric oxide donor showed phytotoxicity to detached tomato leaves 1 day after petiole feeding showing reduced fresh weight. Both H₂O₂and SNP have in vitro antibacterial activities against R. solanacearum in a dose-dependent manner, as well as plant protection in detached tomato leaves against bacterial wilt by 10⁶ and 10⁷ cfu/ml of R. solanacearum. H₂O₂- and SNP-mediated protection was also evaluated in pots using soil-drench treatment with the bacterial inoculation, and relative ‘area under the disease progressive curve (AUDPC’ was calculated to compare disease protection by H₂O₂ and/or SNP with untreated control. Neither H₂O₂ nor SNP protect the tomato seedlings from the bacterial wilt, but H₂O₂+ SNP mixture significantly decreased disease severity with reduced relative AUDPC. These results suggest that H₂O₂ and SNP could be used together to control bacterial wilt in tomato plants as bactericidal agents.

Combined inoculation of Pseudomonas fluorescens and Trichoderma harzianum for enhancing plant growth of vanilla (Vanilla planifolia).

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Sandheep, A R; Asok, A K; Jisha, M S

2013-06-15

This study was conducted to evaluate the plant growth promoting efficiency of combined inoculation of rhizobacteria on Vanilla plants. Based on the in vitro performance of indigenous Trichoderma spp. and Pseudomonas spp., four effective antagonists were selected and screened under greenhouse experiment for their growth enhancement potential. The maximum percentage of growth enhancement were observed in the combination of Trichoderma harzianum with Pseudomonas fluorescens treatment followed by Pseudomonas fluorescens, Trichoderma harzianum, Pseudomonas putida and Trichoderma virens, respectively in decreasing order. Combined inoculation of Trichoderma harzianum and Pseudomonas fluorescens registered the maximum length of vine (82.88 cm), highest number of leaves (26.67/plant), recorded the highest fresh weight of shoots (61.54 g plant(-1)), fresh weight of roots (4.46 g plant(-1)) and dry weight of shoot (4.56 g plant(-1)) where as the highest dry weight of roots (2.0806 g plant(-1)) were achieved with treatments of Pseudomonas fluorescens. Among the inoculated strains, combined inoculation of Trichoderma harzianum and Pseudomonas fluorescens recorded the maximum nitrogen uptake (61.28 mg plant(-1)) followed by the combined inoculation of Trichoderma harzianum (std) and Pseudomonas fluorescens (std) (55.03 mg plant(-1)) and the highest phosphorus uptake (38.80 mg plant(-1)) was recorded in dual inoculation of Trichoderma harzianum and Pseudomonas fluorescens.

Significance of Herbaspirillum seropedicae inoculation and/or straw amendment on growth and dinitrogen fixation of wheat using 15N-dilution method.

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el-Komy, H M; Saad, O A; Hetta, A M

2003-01-01

The effect of Herbaspirillum seropedicae inoculation and/or maize straw (0, 5 and 10 Mg/hm2) amendment on the growth and N2 fixation of wheat was determined in pot experiments using 15N-dilution method. Inoculation resulted in accumulation of fixed nitrogen, and % N from atmosphere being 24.6 and 26.5% in wheat shoot and grain, respectively. Straw amendment reduced % Natm to 16.1 and 20.2% at high straw level (10 Mg/hm2). Rational nitrogen fertilization (180 kg N/hm2) completely inhibited N2 fixation by H. seropedicae inoculation. Bacterial inoculation increased dry shoot and grain yield up to 23 and 31%, respectively. The highest levels of shoot and grain dry mass (46.5 and 42.4%) were obtained by N-fertilization in both inoculated and uninoculated plants. Total shoot and grain N-yield increased irrespective of organic matter amendment by inoculation up to 9 and 25%, respectively. N-fertilized plants recorded a maximum increase in N-yield (57 and 51%). H. seropedicae was reisolated from inoculated wheat histosphere after harvesting (90 d from sowing). Neither organic matter nor mineral nitrogen applications had any marked effect on bacterial total counts colonizing wheat histosphere. Moreover, no symptoms of mottled stripe disease were observed on leaves and stems of inoculated plants.

Comparison of Inoculation with the InoqulA and WASP Automated Systems with Manual Inoculation

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Croxatto, Antony; Dijkstra, Klaas; Prod'hom, Guy

2015-01-01

The quality of sample inoculation is critical for achieving an optimal yield of discrete colonies in both monomicrobial and polymicrobial samples to perform identification and antibiotic susceptibility testing. Consequently, we compared the performance between the InoqulA (BD Kiestra), the WASP (Copan), and manual inoculation methods. Defined mono- and polymicrobial samples of 4 bacterial species and cloudy urine specimens were inoculated on chromogenic agar by the InoqulA, the WASP, and manual methods. Images taken with ImagA (BD Kiestra) were analyzed with the VisionLab version 3.43 image analysis software to assess the quality of growth and to prevent subjective interpretation of the data. A 3- to 10-fold higher yield of discrete colonies was observed following automated inoculation with both the InoqulA and WASP systems than that with manual inoculation. The difference in performance between automated and manual inoculation was mainly observed at concentrations of >106 bacteria/ml. Inoculation with the InoqulA system allowed us to obtain significantly more discrete colonies than the WASP system at concentrations of >107 bacteria/ml. However, the level of difference observed was bacterial species dependent. Discrete colonies of bacteria present in 100- to 1,000-fold lower concentrations than the most concentrated populations in defined polymicrobial samples were not reproducibly recovered, even with the automated systems. The analysis of cloudy urine specimens showed that InoqulA inoculation provided a statistically significantly higher number of discrete colonies than that with WASP and manual inoculation. Consequently, the automated InoqulA inoculation greatly decreased the requirement for bacterial subculture and thus resulted in a significant reduction in the time to results, laboratory workload, and laboratory costs. PMID:25972424

Robust biological nitrogen fixation in a model grass-bacterial association.

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Pankievicz, Vânia C S; do Amaral, Fernanda P; Santos, Karina F D N; Agtuca, Beverly; Xu, Youwen; Schueller, Michael J; Arisi, Ana Carolina M; Steffens, Maria B R; de Souza, Emanuel M; Pedrosa, Fábio O; Stacey, Gary; Ferrieri, Richard A

2015-03-01

Nitrogen-fixing rhizobacteria can promote plant growth; however, it is controversial whether biological nitrogen fixation (BNF) from associative interaction contributes to growth promotion. The roots of Setaria viridis, a model C4 grass, were effectively colonized by bacterial inoculants resulting in a significant enhancement of growth. Nitrogen-13 tracer studies provided direct evidence for tracer uptake by the host plant and incorporation into protein. Indeed, plants showed robust growth under nitrogen-limiting conditions when inoculated with an ammonium-excreting strain of Azospirillum brasilense. (11)C-labeling experiments showed that patterns in central carbon metabolism and resource allocation exhibited by nitrogen-starved plants were largely reversed by bacterial inoculation, such that they resembled plants grown under nitrogen-sufficient conditions. Adoption of S. viridis as a model should promote research into the mechanisms of associative nitrogen fixation with the ultimate goal of greater adoption of BNF for sustainable crop production. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Bacterially Induced Weathering of Ultramafic Rock and Its Implications for Phytoextraction

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Kidd, Petra; Kuffner, Melanie; Prieto-Fernández, Ángeles; Hann, Stephan; Monterroso, Carmela; Sessitsch, Angela; Wenzel, Walter; Puschenreiter, Markus

2013-01-01

The bioavailability of metals in soil is often cited as a limiting factor of phytoextraction (or phytomining). Bacterial metabolites, such as organic acids, siderophores, or biosurfactants, have been shown to mobilize metals, and their use to improve metal extraction has been proposed. In this study, the weathering capacities of, and Ni mobilization by, bacterial strains were evaluated. Minimal medium containing ground ultramafic rock was inoculated with either of two Arthrobacter strains: LA44 (indole acetic acid [IAA] producer) or SBA82 (siderophore producer, PO4 solubilizer, and IAA producer). Trace elements and organic compounds were determined in aliquots taken at different time intervals after inoculation. Trace metal fractionation was carried out on the remaining rock at the end of the experiment. The results suggest that the strains act upon different mineral phases. LA44 is a more efficient Ni mobilizer, apparently solubilizing Ni associated with Mn oxides, and this appeared to be related to oxalate production. SBA82 also leads to release of Ni and Mn, albeit to a much lower extent. In this case, the concurrent mobilization of Fe and Si indicates preferential weathering of Fe oxides and serpentine minerals, possibly related to the siderophore production capacity of the strain. The same bacterial strains were tested in a soil-plant system: the Ni hyperaccumulator Alyssum serpyllifolium subsp. malacitanum was grown in ultramafic soil in a rhizobox system and inoculated with each bacterial strain. At harvest, biomass production and shoot Ni concentrations were higher in plants from inoculated pots than from noninoculated pots. Ni yield was significantly enhanced in plants inoculated with LA44. These results suggest that Ni-mobilizing inoculants could be useful for improving Ni uptake by hyperaccumulator plants. PMID:23793627

Effects of pre- and post-transplant inoculation with commercial arbuscular mycorrhizal (AM fungi on pelargonium (Pelargonium hortorum and its microorganism community

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Gergely Csima

2012-03-01

Full Text Available Rooted cuttings of geranium were grown with and without a slow release fertilizer and inoculated or not with a commercial inoculum containing AM fungi. After six weeks plants were transplanted into larger containers and one-half of the plants were inoculated with AM. Inoculation increased pelargonium growth along with nitrogen, phosphorous and potassium concentrations in shoot than caused a slight decrease in shoot growth and enhanced N concentration. Colony forming units of total fungi and bacteria in the rhizosphere were not influenced by AM;  although RFLP profiles of DNA isolated from bacteria living in rhizosphere showed a more diverse community in AM-inoculated than non-inoculated plants at low nutrient supply. Our results suggest that mycorrhizal inoculation not only has an effect on plant growth and uptake of elements but it also influences directly or indirectly the bacterial community of the rhizosphere.

Combined use of alkane-degrading and plant growth-promoting bacteria enhanced phytoremediation of diesel contaminated soil.

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Tara, Nain; Afzal, Muhammad; Ansari, Tariq M; Tahseen, Razia; Iqbal, Samina; Khan, Qaiser M

2014-01-01

Inoculation of plants with pollutant-degrading and plant growth-promoting microorganisms is a simple strategy to enhance phytoremediation activity. The objective of this study was to determine the effect of inoculation of different bacterial strains, possessing alkane-degradation and 1-amino-cyclopropane-1 -carboxylic acid (ACC) deaminase activity, on plant growth and phytoremediation activity. Carpet grass (Axonopus affinis) was planted in soil spiked with diesel (1% w/w) for 90 days and inoculated with different bacterial strains, Pseudomonas sp. ITRH25, Pantoea sp. BTRH79 and Burkholderia sp. PsJN, individually and in combination. Generally, bacterial application increased total numbers of culturable hydrocarbon-degrading bacteria in the rhizosphere ofcarpet grass, plant biomass production, hydrocarbon degradation and reduced genotoxicity. Bacterial strains possessing different beneficial traits affect plant growth and phytoremediation activity in different ways. Maximum bacterial population, plant biomass production and hydrocarbon degradation were achieved when carpet grass was inoculated with a consortium of three strains. Enhanced plant biomass production and hydrocarbon degradation were associated with increased numbers of culturable hydrocarbon-degrading bacteria in the rhizosphere of carpet grass. The present study revealed that the combined use of different bacterial strains, exhibiting different beneficial traits, is a highly effective strategy to improve plant growth and phytoremediation activity.

Identification of plant compounds involved in the microbe-plant communication during the co-inoculation of soybean with Bradyrhizobium elkanii and Delftia sp. JD2.

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Cagide, Celica; Riviezzi, Braulio; Minteguiaga, Manuel; Morel, Maria; Castro-Sowinski, Susana

2018-05-30

Delftia sp. JD2 is a Betaproteobacterium characterized as a plant growth-promoting bacterium with a "helper" function, enhancing the performance of rhizobial inoculant strains during the co-inoculation of alfalfa and clover. In this work we analyzed: (i) the effect of the co-inoculation with Bradyrhizobium elkanii and Delftia sp. JD2 strains on the performance of soybean plants and, (ii) the production of a few secondary plant metabolites that would explain the positive effect of co-inoculation on the growth and development of soybean plants. The results showed a beneficial effect of co-inoculation on soybean growth, nodulation rate and pulse yield, with the concomitant benefit for the agricultural economy. In addition, based on a metabolomics approach, we demonstrated that a different pattern of plant metabolites is being produced at different stages of plant growth. The new information suggests that the co-inoculation of soybean changes the primary and secondary metabolism of the plant, including changes in the metabolic status of main and secondary nodules within the plant. The relevance of producing a different pattern of photosynthetic and photoprotective pigments, flavonoids, organic acids and carbohydrates are discussed. Finally, we propose that JD2 could be used, together with bradyrhizobia, to manipulate the chemical composition of plant tissues, promoting the nutritional benefits and health of soybean.

Bacillus pumilus ES4: candidate plant growth-promoting bacterium to enhance establishment of plants in mine tailings

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de-Bashan, Luz E.; Hernandez, Juan-Pablo; Bashan, Yoav; Maier, Raina

2014-01-01

Three plant growth-promoting bacteria (PGPB; Bacillus pumilus ES4, B. pumilus RIZO1, and Azospirillum brasilense Cd) were tested for their ability to enhance plant growth and development of the native Sonoran Desert shrub quailbush (Atriplex lentiformis) and for their effect on the native bacterial community in moderately acidic, high-metal content (AHMT) and in neutral, low metal content natural tailings (NLMT) in controlled greenhouse experiments. Inoculation of quailbush with all three PGPB significantly enhanced plant growth parameters, such as germination, root length, dry weight of shoots and roots, and root/shoot ratio in both types of tailings. The effect of inoculation on the indigenous bacterial community by the most successful PGPB Bacillus pumilus ES4 was evaluated by denaturating gradient gel electrophoresis (PCR-DGGE) fingerprinting and root colonization was followed by specific fluorescent in situ hybridization (FISH). Inoculation with this strain significantly changed the bacterial community over a period of 60 days. FISH analysis showed that the preferred site of colonization was the root tips and root elongation area. This study shows that inoculation of native perennial plants with PGPB can be used for developing technologies for phytostabilizing mine tailings. PMID:25009362

Bacterial degradation of Aroclor 1242 in the mycorrhizosphere soils of zucchini (Cucurbita pepo L.) inoculated with arbuscular mycorrhizal fungi.

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Qin, Hua; Brookes, Philip C; Xu, Jianming; Feng, Youzhi

2014-11-01

A greenhouse experiment was conducted to investigate the effects of zucchini (Cucurbita pepo L.), inoculated with the arbuscular mycorrhizal (AM) species Acaulospora laevis, Glomus caledonium, and Glomus mosseae, on the soil bacterial community responsible for Aroclor 1242 dissipation. The dissipation rates of Aroclor 1242 and soil bacteria abundance were much higher with the A. laevis and G. mosseae treatments compared to the non-mycorrhizal control. The biphenyl dioxygenase (bphA) and Rhodococcus-like 2,3-dihydroxybiphenyl dioxygenase (bphC) genes were more abundant in AM inoculated soils, suggesting that the bphA and Rhodococcus-like bphC pathways play an important role in Aroclor 1242 dissipation in the mycorrhizosphere. The soil bacterial communities were dominated by classes Betaproteobacteria and Actinobacteria, while the relative proportion of Actinobacteria was significantly (F=2.288, P<0.05) correlated with the PCB congener profile in bulk soil. Our results showed that AM fungi could enhance PCB dissipation by stimulating bph gene abundance and the growth of specific bacterial groups.

Changes in ruminal bacterial community composition following feeding of alfalfa ensiled with a lactic acid bacterial inoculant.

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Mohammed, R; Stevenson, D M; Beauchemin, K A; Muck, R E; Weimer, P J

2012-01-01

Some silage inoculants help to improve silage quality and promote an increase in milk production, possibly through altering the rumen microflora. We hypothesized that rumen bacterial community composition (BCC) would be different in cows fed alfalfa ensiled with the inoculant Lactobacillus plantarum MTD/1 (LP) compared with those fed alfalfa ensiled without the inoculant (Ctrl). Eight ruminally cannulated Holstein cows were allotted to 2 diets (Ctrl or LP) in a double crossover design with four 28-d periods. Diets were formulated to contain (% dry matter basis) 28.0% neutral detergent fiber and 16.2% crude protein, and contained alfalfa silage, 50.9; corn silage, 20.6; high-moisture shelled corn, 21.4; soy hulls, 4.7; plus minerals and vitamins, 2.4. Ruminal digesta were collected just before feeding on 3 consecutive days near the end of each period, and were separated into solid and liquid phases. Microbial DNA was extracted from each phase, amplified by PCR using domain-level bacterial primers, and subjected to automated ribosomal intergenic spacer analysis. The pH was 4.56 and 4.86 and the lactate-to-acetate ratio 9.8 and 4.4, respectively, for the treated and untreated alfalfa silages. Dry matter intakes and milk production data were not influenced by diets but showed a cow effect. Total volatile fatty acids (mM) tended to be greater for LP compared with Ctrl. Individual volatile fatty acids were not influenced by diets but showed a significant cow effect. Ruminal acetate (mol/100 mol) and acetate-to-propionate ratio were lower and propionate (mol/100 mol) greater for the 2 milk fat-depressed (MFD; content) cows compared with the other 6 cows. Correspondence analysis of the 265 peaks in the automated ribosomal intergenic spacer analysis profile across the 188 samples revealed that the first 2 components contributed 7.1 and 3.8% to the total variation in the profile. The ordination points representing the liquid and solid phases clustered separately, indicating

Bacterial antagonists of fungal pathogens also control root-knot nematodes by induced systemic resistance of tomato plants.

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Mohamed Adam

Full Text Available The potential of bacterial antagonists of fungal pathogens to control the root-knot nematode Meloidogyne incognita was investigated under greenhouse conditions. Treatment of tomato seeds with several strains significantly reduced the numbers of galls and egg masses compared with the untreated control. Best performed Bacillus subtilis isolates Sb4-23, Mc5-Re2, and Mc2-Re2, which were further studied for their mode of action with regard to direct effects by bacterial metabolites or repellents, and plant mediated effects. Drenching of soil with culture supernatants significantly reduced the number of egg masses produced by M. incognita on tomato by up to 62% compared to the control without culture supernatant. Repellence of juveniles by the antagonists was shown in a linked twin-pot set-up, where a majority of juveniles penetrated roots on the side without inoculated antagonists. All tested biocontrol strains induced systemic resistance against M. incognita in tomato, as revealed in a split-root system where the bacteria and the nematodes were inoculated at spatially separated roots of the same plant. This reduced the production of egg masses by up to 51%, while inoculation of bacteria and nematodes in the same pot had only a minor additive effect on suppression of M. incognita compared to induced systemic resistance alone. Therefore, the plant mediated effect was the major reason for antagonism rather than direct mechanisms. In conclusion, the bacteria known for their antagonistic potential against fungal pathogens also suppressed M. incognita. Such "multi-purpose" bacteria might provide new options for control strategies, especially with respect to nematode-fungus disease complexes that cause synergistic yield losses.

Bacterial antagonists of fungal pathogens also control root-knot nematodes by induced systemic resistance of tomato plants.

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Adam, Mohamed; Heuer, Holger; Hallmann, Johannes

2014-01-01

The potential of bacterial antagonists of fungal pathogens to control the root-knot nematode Meloidogyne incognita was investigated under greenhouse conditions. Treatment of tomato seeds with several strains significantly reduced the numbers of galls and egg masses compared with the untreated control. Best performed Bacillus subtilis isolates Sb4-23, Mc5-Re2, and Mc2-Re2, which were further studied for their mode of action with regard to direct effects by bacterial metabolites or repellents, and plant mediated effects. Drenching of soil with culture supernatants significantly reduced the number of egg masses produced by M. incognita on tomato by up to 62% compared to the control without culture supernatant. Repellence of juveniles by the antagonists was shown in a linked twin-pot set-up, where a majority of juveniles penetrated roots on the side without inoculated antagonists. All tested biocontrol strains induced systemic resistance against M. incognita in tomato, as revealed in a split-root system where the bacteria and the nematodes were inoculated at spatially separated roots of the same plant. This reduced the production of egg masses by up to 51%, while inoculation of bacteria and nematodes in the same pot had only a minor additive effect on suppression of M. incognita compared to induced systemic resistance alone. Therefore, the plant mediated effect was the major reason for antagonism rather than direct mechanisms. In conclusion, the bacteria known for their antagonistic potential against fungal pathogens also suppressed M. incognita. Such "multi-purpose" bacteria might provide new options for control strategies, especially with respect to nematode-fungus disease complexes that cause synergistic yield losses.

Effects of Rhizobium inoculation on Trifolium resupinatum antioxidant system under sulfur dioxide pollution

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Ladan Bayat

2014-01-01

Full Text Available Introduction: Plant growth stimulating rhizobacteria are beneficial bacteria that can cause resistance to various stresses in plants. One of these stresses is SO2 air pollution. SO2 is known as a strong damaging air pollutant that limits growth of plants. The aim of this study is evaluation of the effects of bacterial inoculation with native and standard Rhizobium on Persian clover root growth and antioxidants activity and capacity under air SO2 pollution. Materials and methods: In this study, 31 days plants (no-inoculated and inoculated with two strains of Rhizobium exposed to the different concentrations of SO2 (0 as a control, 0.5, 1, 1.5 and 2 ppm for 5 consecutive days and 2 hours per day. Results: Results showed different concentrations of SO2 had a significant effect on Persian clover root weight and antioxidant system. Increasing SO2 stress decreased root fresh and dry weight and antioxidant capacities (IC50 and increased antioxidant activities (I% of Persian clover leaves significantly in comparison to the control plants (under 0 ppm and increased SOD, CAT and GPX activity. Inoculation of Persian clover plants with native and standard Rhizobium increased root weight and did not show a significant effect on antioxidants activity and capacity, but interaction between Rhizobium inoculation and SO2 treatment reduced significantly the stress effects of high concentration of SO2 on root growth and antioxidants activity and capacity. In fact, level of this change of root growth and antioxidant system under SO2 pollution stress in inoculated plants was lower than in the non-inoculated plants. Discussion and conclusion: As a result, an increase in SO2 concentration caused a decrease in root weight, increase in antioxidants activity and capacity of Persian clover. Inoculation with Rhizobium strains could alleviate the effect of SO2 pollution on antioxidant system by effects on root growth.

Effect of the different timing of AMF inoculation on plant growth and flower quality of chrysanthemum

NARCIS (Netherlands)

Sohn, B.K.; Kim, K.Y.; Chung, S.J.; Kim, W.S.; Park, S.M.; Kang, J.G.; Rim, Y.S.; Cho, J.S.; Kim, T.H.; Lee, J.H.

2003-01-01

Plant growth and flower quality of an ornamental plant (Chrysanthemum morifolium Ramat) var. Baekgwang in response to the different timing of arbuscular mycorrhizal fungi (AMF) inoculation were examined. To evaluate the effects of AMF inoculation timing on growth of chrysanthemum cuttings, AMF was

Bacterial spot and early blight biocontrol by epiphytic bacteria in tomato plants

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Roberto Lanna Filho

2010-12-01

Full Text Available The objective of this work was to evaluate in vitro and in vivo biocontrol of bacterial spot (Xanthomonas vesicatoria and early blight (Alternaria solani by the epiphytic bacteria Paenibacillus macerans and Bacillus pumilus. Tomato plants were previously sprayed with epiphytic bacteria, benzalkonium chloride and PBS buffer and, after four days, they were inoculated with A. solani and X. vesicatoria. To determine the phytopathogenic bacteria population, leaflet samples were collected from each treatment every 24 hours, for seven days, and plated on semi-selective medium. The effect of epiphytic bacteria over phytopathogens was performed by the antibiosis test and antagonistic activity measured by inhibition zone diameter. The epiphytic and benzalkonium chloride drastically reduced the severity of early blight and bacterial spot in comparison to the control (PBS. In detached leaflets, the epiphytic bacteria reduced in 70% the number of phytopathogenic bacteria cells in the phylloplane. The antibiosis test showed that the epiphytic bacteria efficiently inhibit the phytopathogens growth. In all the bioassays, the epiphytic bacteria protect tomato plants against the phytopathogens

Combined endophytic inoculants enhance nickel phytoextraction from serpentine soil in the hyperaccumulator Noccaea caerulescens.

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Visioli, Giovanna; Vamerali, Teofilo; Mattarozzi, Monica; Dramis, Lucia; Sanangelantoni, Anna M

2015-01-01

This study assesses the effects of specific bacterial endophytes on the phytoextraction capacity of the Ni-hyperaccumulator Noccaea caerulescens, spontaneously growing in a serpentine soil environment. Five metal-tolerant endophytes had already been selected for their high Ni tolerance (6 mM) and plant growth promoting ability. Here we demonstrate that individual bacterial inoculation is ineffective in enhancing Ni translocation and growth of N. caerulescens in serpentine soil, except for specific strains Ncr-1 and Ncr-8, belonging to the Arthrobacter and Microbacterium genera, which showed the highest indole acetic acid production and 1-aminocyclopropane-1-carboxylic acid-deaminase activity. Ncr-1 and Ncr-8 co-inoculation was even more efficient in promoting plant growth, soil Ni removal, and translocation of Ni, together with that of Fe, Co, and Cu. Bacteria of both strains densely colonized the root surfaces and intercellular spaces of leaf epidermal tissue. These two bacterial strains also turned out to stimulate root length, shoot biomass, and Ni uptake in Arabidopsis thaliana grown in MS agar medium supplemented with Ni. It is concluded that adaptation of N. caerulescens in highly Ni-contaminated serpentine soil can be enhanced by an integrated community of bacterial endophytes rather than by single strains; of the former, Arthrobacter and Microbacterium may be useful candidates for future phytoremediation trials in multiple metal-contaminated sites, with possible extension to non-hyperaccumulator plants.

Agrobacterium-mediated inoculation of chrysanthemum (Chrysanthemum morifolium) plants with chrysanthemum stunt viroid.

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Nabeshima, Tomoyuki; Doi, Motoaki; Hosokawa, Munetaka

2016-08-01

Agroinfiltration was tested as a method of inoculation of chrysanthemum plants with chrysanthemum stunt viroid (CSVd). Binary vectors harboring dimeric CSVd sequences in sense and antisense orientations were constructed, and Agrobacterium transfected with these binary vectors was infiltrated into chrysanthemum leaves. Northern blotting and reverse transcription polymerase chain reaction analysis showed that local infection was established within 7 days and systemic infection within 20 days. CSVd polarities showed no difference in infectivity. This study showed that agroinfiltration of chrysanthemum plants is an easy, rapid, and cost-effective method for CSVd inoculation. Copyright © 2016 Elsevier B.V. All rights reserved.

Does co-inoculation of Lactuca serriola with endophytic and arbuscular mycorrhizal fungi improve plant growth in a polluted environment?

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Ważny, Rafał; Rozpądek, Piotr; Jędrzejczyk, Roman J; Śliwa, Marta; Stojakowska, Anna; Anielska, Teresa; Turnau, Katarzyna

2018-04-01

Phytoremediation of polluted sites can be improved by co-inoculation with mycorrhizal and endophytic fungi. In this study, the effects of single- and co-inoculation of Lactuca serriola with an arbuscular mycorrhizal (AM) fungus, Rhizoglomus intraradices, and endophytic fungi, Mucor sp. or Trichoderma asperellum, on plant growth, vitality, toxic metal accumulation, sesquiterpene lactone production and flavonoid concentration in the presence of toxic metals were evaluated. Inoculation with the AM fungus increased biomass yield of the plants grown on non-polluted and polluted substrate. Co-inoculation with the AM fungus and Mucor sp. resulted in increased biomass yield of plants cultivated on the polluted substrate, whereas co-inoculation with T. asperellum and the AM fungus increased plant biomass on the non-polluted substrate. In the presence of Mucor sp., mycorrhizal colonization and arbuscule richness were increased in the non-polluted substrate. Co-inoculation with the AM fungus and Mucor sp. increased Zn concentration in leaves and roots. The concentration of sesquiterpene lactones in plant leaves was decreased by AM fungus inoculation in both substrates. Despite enhanced host plant costs caused by maintaining symbiosis with numerous microorganisms, interaction of wild lettuce with both mycorrhizal and endophytic fungi was more beneficial than that with a single fungus. The study shows the potential of double inoculation in unfavourable environments, including agricultural areas and toxic metal-polluted areas.

Differential Control Efficacies of Vitamin Treatments against Bacterial Wilt and Grey Mould Diseases in Tomato Plants

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Jeum Kyu Hong

2016-10-01

Full Text Available Bacterial wilt and grey mould in tomato plants are economically destructive bacterial and fungal diseases caused by Ralstonia solanacearum and Botrytis cinerea, respectively. Various approaches including chemical and biological controls have been attempted to arrest the tomato diseases so far. In this study, in vitro growths of bacterial R. solanacearum and fungal B. cinerea were evaluated using four different vitamins including thiamine (vitamin B1, niacin (vitamin B3, pyridoxine (vitamin B6, and menadione (vitamin K3. In planta efficacies of the four vitamin treatments on tomato protection against both diseases were also demonstrated. All four vitamins showed different in vitro antibacterial activities against R. solanacearum in dose-dependent manners. However, treatment with 2 mM thiamine was only effective in reducing bacterial wilt of detached tomato leaves without phytotoxicity under lower disease pressure (10⁶ colony-forming unit [cfu]/ml. Treatment with the vitamins also differentially reduced in vitro conidial germination and mycelial growth of B. cinerea. The four vitamins slightly reduced the conidial germination, and thiamine, pyridoxine and menadione inhibited the mycelial growth of B. cinerea. Menadione began to drastically suppress the conidial germination and mycelial growth by 5 and 0.5 mM, respectively. Grey mould symptoms on the inoculated tomato leaves were significantly reduced by pyridoxine and menadione pretreatments one day prior to the fungal challenge inoculation. These findings suggest that disease-specific vitamin treatment will be integrated for eco-friendly management of tomato bacterial wilt and grey mould.

Differential Control Efficacies of Vitamin Treatments against Bacterial Wilt and Grey Mould Diseases in Tomato Plants.

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Hong, Jeum Kyu; Kim, Hyeon Ji; Jung, Heesoo; Yang, Hye Ji; Kim, Do Hoon; Sung, Chang Hyun; Park, Chang-Jin; Chang, Seog Won

2016-10-01

Bacterial wilt and grey mould in tomato plants are economically destructive bacterial and fungal diseases caused by Ralstonia solanacearum and Botrytis cinerea , respectively. Various approaches including chemical and biological controls have been attempted to arrest the tomato diseases so far. In this study, in vitro growths of bacterial R. solanacearum and fungal B. cinerea were evaluated using four different vitamins including thiamine (vitamin B1), niacin (vitamin B3), pyridoxine (vitamin B6), and menadione (vitamin K3). In planta efficacies of the four vitamin treatments on tomato protection against both diseases were also demonstrated. All four vitamins showed different in vitro antibacterial activities against R. solanacearum in dose-dependent manners. However, treatment with 2 mM thiamine was only effective in reducing bacterial wilt of detached tomato leaves without phytotoxicity under lower disease pressure (10 6 colony-forming unit [cfu]/ml). Treatment with the vitamins also differentially reduced in vitro conidial germination and mycelial growth of B. cinerea . The four vitamins slightly reduced the conidial germination, and thiamine, pyridoxine and menadione inhibited the mycelial growth of B. cinerea . Menadione began to drastically suppress the conidial germination and mycelial growth by 5 and 0.5 mM, respectively. Grey mould symptoms on the inoculated tomato leaves were significantly reduced by pyridoxine and menadione pretreatments one day prior to the fungal challenge inoculation. These findings suggest that disease-specific vitamin treatment will be integrated for eco-friendly management of tomato bacterial wilt and grey mould.

Effect of seed inoculation with Azospirillum brasilense and nitrogen fertilization rates on maize plant yield and silage quality

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Fernando Reimann Skonieski

Full Text Available ABSTRACT The objective of this study was to determine the effect of Azospirillum brasilense inoculation and different nitrogen (N rates applied as topdressing on the productivity of a maize crop and the nutritional value of maize silage. Two experiments were conducted in the 2012/2013 and 2013/2014 harvests. Treatments were distributed in a randomized block design in a factorial arrangement, which consisted of two maize hybrids (AS 1572 and Defender coupled with nitrogen rates (0, 60, 120, 240, and 480 kg ha-1, inoculated or uninoculated with A. brasilense. Inoculated seeds were treated with the A. brasilense strains Ab-V5 and Ab-V6. Inoculation with A. brasilense showed interaction with the hybrids, agricultural years, and nitrogen rates for the maize plant yield. In the 2012/2013 agricultural year, inoculation increased the AS 1572 hybrid silage yield by 6.16% and, in the 2013/2014 harvest, A. brasilense inoculation produced an increase of 16.15% for the Defender hybrid. Nitrogen fertilization applied at 0, 60, and 120 kg ha-1 N benefited the plants inoculated with A. brasilense. The statistical equations revealed that N rates between 0 and 184 kg ha-1 in A. brasilense inoculated plants raised the plant productivity for silage when compared with the control plants. Regarding the nutritional value of the silage, inoculation with A. brasilense increased the ether extract levels and total digestible nutrients and reduced the amount of acid detergent fiber. For all this, positive results with inoculation for silage yield are dependent on nitrogen fertilization rate. Inoculation with A. brasilense can promote changes in the maize silage quality, but with obtained results it is not possible to definitely conclude upon nutritive value of maize silage.

The nematicidal effect of some bacterial biofertilizers on Meloidogyne incognita in sandy soil

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M.E El-Hadad

2011-03-01

Full Text Available In a greenhouse experiment, the nematicidal effect of some bacterial biofertilizers including the nitrogen fixing bacteria (NFB Paenibacillus polymyxa (four strains, the phosphate solubilizing bacteria (PSB Bacillus megaterium (three strains and the potassium solubilizing bacteria (KSB B. circulans (three strains were evaluated individually on tomato plants infested with the root-knot nematode Meloidogyne incognita in potted sandy soil. Comparing with the uninoculated nematode-infested control, the inoculation with P. polymyxa NFB7, B. megaterium PSB2 and B. circulans KSB2, increased the counts of total bacteria and total bacterial spores in plants potted soil from 1.2 to 2.6 folds estimated 60 days post-inoculation. Consequently, the inoculation with P. polymyxa NFB7 increased significantly the shoot length (cm, number of leaves / plant, shoot dry weight (g / plant and root dry weight (g / plant by 32.6 %, 30.8 %, 70.3 % and 14.2 %, respectively. Generally, the majority treatments significantly reduced the nematode multiplication which was more obvious after 60 days of inoculation. Among the applied strains, P. polymyxa NFB7, B. megaterium PSB2 and B. circulans KSB2 inoculations resulted in the highest reduction in nematode population comparing with the uninoculated nematode-infested control. They recorded the highest reduction in numbers of hatched juveniles/root by 95.8 %, females/root by 63.75 % and juveniles/1kg soil by 57.8 %. These results indicated that these bacterial biofertilizers are promising double purpose microorganisms for mobilizing of soil nutrients (nitrogen, phosphate and potassium and for the biological control of M. incognita.

Phytohormones and induction of plant-stress tolerance and defense genes by seed and foliar inoculation with Azospirillum brasilense cells and metabolites promote maize growth.

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Fukami, Josiane; Ollero, Francisco Javier; Megías, Manuel; Hungria, Mariangela

2017-12-01

Azospirillum spp. are plant-growth-promoting bacteria used worldwide as inoculants for a variety of crops. Among the beneficial mechanisms associated with Azospirillum inoculation, emphasis has been given to the biological nitrogen fixation process and to the synthesis of phytohormones. In Brazil, the application of inoculants containing A. brasilense strains Ab-V5 and Ab-V6 to cereals is exponentially growing and in this study we investigated the effects of maize inoculation with these two strains applied on seeds or by leaf spray at the V2.5 stage growth-a strategy to relieve incompatibility with pesticides used for seed treatment. We also investigate the effects of spraying the metabolites of these two strains at V2.5. Maize growth was promoted by the inoculation of bacteria and their metabolites. When applied via foliar spray, although A. brasilense survival on leaves was confirmed by confocal microscopy and cell recovery, few cells were detected after 24 h, indicating that the effects of bacterial leaf spray might also be related to their metabolites. The major molecules detected in the supernatants of both strains were indole-3-acetic acid, indole-3-ethanol, indole-3-lactic acid and salicylic acid. RT-PCR of genes related to oxidative stress (APX1, APX2, CAT1, SOD2, SOD4) and plant defense (pathogenesis-related PR1, prp2 and prp4) was evaluated on maize leaves and roots. Differences were observed according to the gene, plant tissue, strain and method of application, but, in general, inoculation with Azospirillum resulted in up-regulation of oxidative stress genes in leaves and down-regulation in roots; contrarily, in general, PR genes were down-regulated in leaves and up-regulated in roots. Emphasis should be given to the application of metabolites, especially of Ab-V5 + Ab-V6 that in general resulted in the highest up-regulation of oxidative-stress and PR genes both in leaves and in roots. We hypothesize that the benefits of inoculation of Azospirillum on

Application of customised bacterial inoculants for grass haylage production and its effectiveness on nutrient composition and fermentation quality of haylage.

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Soundharrajan, Ilavenil; Kim, Da Hye; Srisesharam, Srigopalram; Kuppusamy, Palaniselvam; Park, Hyung Soo; Yoon, Yong Hee; Kim, Won Ho; Song, Young Gil; Choi, Ki Choon

2017-10-01

The present study aimed to investigate the efficacy of customised Lactobacillus plantarum KCC-10, KCC-19 and K-46 on nutrient composition and fermentation quality of low moisture Italian ryegrass (IRG) forage. An addition of customised bacterial inoculants (CBI) did not affect the nutrient compositions and digestibility rates of haylage. The lactic acid content was higher in CBI-inoculated haylage, whereas the amount of acetic acid and butyric acid production was significantly reduced than the control. CBI-inoculated haylage exhibited higher numbers of bacterial colonies that reduced the pH of the haylage. Low pH in haylage is an important criterion for preventing undesirable microbial growth and improves fermentation quality of haylage. PCR studies indicated that the DNA of L. plantarum was predominantly amplified. It evidenced that the CBI is the main reason behind the improvement of haylage fermentation as compared to control. Overall results suggested that KCC-10, KCC-19 and K-46 are considered as potent strains for improving fermentation quality of low moisture forage and preserve its stability for a long time.

Combined endophytic inoculants enhance nickel phytoextraction from serpentine soil in the hyperaccumulator Noccaea caerulescens

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Giovanna eVisioli

2015-08-01

Full Text Available This study assesses the effects of specific bacterial endophytes on the phytoextraction capacity of the Ni-hyperaccumulator Noccaea caerulescens, spontaneously growing in a serpentine soil environment. Five metal-tolerant endophytes had already been selected for their high Ni tolerance (6 mM and plant growth promoting ability. Here we demonstrate that individual bacterial inoculation is ineffective in enhancing Ni translocation and growth of N. caerulescens in serpentine soil, except for specific strains Ncr-1 and Ncr-8, belonging to the Arthrobacter and Microbacterium genera, which showed the highest IAA production and ACC-deaminase activity. Ncr-1 and Ncr-8 co-inoculation was even more efficient in promoting plant growth, soil Ni removal and translocation of Ni, together with that of Fe, Co and Cu. Bacteria of both strains densely colonised the root surfaces and intercellular spaces of leaf epidermal tissue. These two bacterial strains also turned out to stimulate root length, shoot biomass and Ni uptake in Arabidopsis thaliana grown in MS agar medium supplemented with Ni. It is concluded that adaptation of N. caerulescens in highly Ni-contaminated serpentine soil can be enhanced by an integrated community of bacterial endophytes rather than by single strains; of the former, Arthrobacter and Microbacterium may be useful candidates for future phytoremediation trials

Inoculation of maize with Azospirillum brasilense in the seed furrow

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Tâmara Prado de Morais

2016-06-01

Full Text Available ABSTRACT Several studies addressing the inoculation of cereals with diazotrophic microorganisms can be found in the literature. However, in many experiments, investigators have overlooked the feasibility of applying these microorganisms to the furrow together with the seed, and the effect of bacterial concentration on phytostimulation. The aim of this work was to evaluate the effect of doses of an inoculant based on Azospirillum brasilense, applied to the seed furrow when planting maize, combined with different doses of nitrogen fertiliser. The experiment was carried out in the field, in soil of the cerrado region of Brazil. An experimental design of randomised blocks in bands was adopted, comprising nitrogen (40, 100, 200 and 300 kg ha-1 and doses of an A. brasilense-based liquid inoculant applied to the seed furrow (0, 100, 200, 300 and 400 mL ha-1. The dose of 200 mL ha-1Azospirillum was noteworthy for grain production. This is the first report of the effective application of Azospirillum in the seed furrow when planting maize in the cerrado region of Brazil.

Plant-plant competition outcomes are modulated by plant effects on the soil bacterial community.

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Hortal, S; Lozano, Y M; Bastida, F; Armas, C; Moreno, J L; Garcia, C; Pugnaire, F I

2017-12-19

Competition is a key process that determines plant community structure and dynamics, often mediated by nutrients and water availability. However, the role of soil microorganisms on plant competition, and the links between above- and belowground processes, are not well understood. Here we show that the effects of interspecific plant competition on plant performance are mediated by feedbacks between plants and soil bacterial communities. Each plant species selects a singular community of soil microorganisms in its rhizosphere with a specific species composition, abundance and activity. When two plant species interact, the resulting soil bacterial community matches that of the most competitive plant species, suggesting strong competitive interactions between soil bacterial communities as well. We propose a novel mechanism by which changes in belowground bacterial communities promoted by the most competitive plant species influence plant performance and competition outcome. These findings emphasise the strong links between plant and soil communities, paving the way to a better understanding of plant community dynamics and the effects of soil bacterial communities on ecosystem functioning and services.

Estimation of Nitrogenase Enzyme Activities and Plant Growth of Legume and Non-legume Inoculated with Diazotrophic Bacteria

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Salwani S.

2012-06-01

Full Text Available Biological Nitrogen Fixation (BNF process benefits the agriculture sector especially for reducing cost of nitrogenfertilizer. In the process, the diazotrophs convert N2 into ammonia (NH3 which is useable by plants. The BNF process iscatalysed by nitrogenase enzyme that involved protons and electrons together with evolution of H2 therefore, theassessment of N2 fixation is also available via H2 production and electron allocation analysis. Thus, the aims of thisexperiment were to estimate the nitrogenase enzyme activities and observe the influence of diazothrophs on growth oflegume (soybean and non legume (rice plants. Host plants were inoculated with respective inocula; Bradyrhizobiumjaponicum (strain 532C for soybean while Azospirillum brasilense (Sp7 and locally isolated diazotroph (isolate 5 forrice. At harvest, the plants were observed for plant growth parameters, H2 evolution, N2 fixation and electron allocationcoefficient (EAC values. The experiment recorded N2 fixation activities of inoculated soybean plants at 141.2 μmol N2 h-1g-1 dry weight nodule, and the evolution of H2 at 144.4 μmol H2 h-1 g-1 dry weight nodule. The electron allocationcoefficient (EAC of soybean was recorded at 0.982. For inoculated rice plants, none of the observations was successfully recorded. However, results for chlorophyll contents and plant dry weight of both plants inoculated with respective inocula were similar to the control treatments supplied with full nitrogen fertilization (+N. The experiment clearly showed that inoculation of diazotrophic bacteria could enhance growth of the host plants similar to plants treated with nitrogenous fertilizer due to efficient N2 fixation process

Alleviation of salt stress by halotolerant and halophilic plant growth-promoting bacteria in wheat (Triticum aestivum

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Furkan Orhan

Full Text Available ABSTRACT In the current study, 18 halotolerant and halophilic bacteria have been investigated for their plant growth promoting abilities in vitro and in a hydroponic culture. The bacterial strains have been investigated for ammonia, indole-3-acetic acid and 1-aminocyclopropane-1-carboxylate-deaminase production, phosphate solubilisation and nitrogen fixation activities. Of the tested bacteria, eight were inoculated with Triticum aestivum in a hydroponic culture. The investigated bacterial strains were found to have different plant-growth promoting activities in vitro. Under salt stress (200 mM NaCl, the investigated bacterial strains significantly increased the root and shoot length and total fresh weight of the plants. The growth rates of the plants inoculated with bacterial strains ranged from 62.2% to 78.1%.Identifying of novel halophilic and halotolerant bacteria that promote plant growth can be used as alternatives for salt sensitive plants. Extensive research has been conducted on several halophilic and halotolerant bacterial strains to investigate their plant growth promoting activities. However, to the best of my knowledge, this is the first study to inoculate these bacterial strains with wheat.

Alleviation of salt stress by halotolerant and halophilic plant growth-promoting bacteria in wheat (Triticum aestivum).

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Orhan, Furkan

2016-01-01

In the current study, 18 halotolerant and halophilic bacteria have been investigated for their plant growth promoting abilities in vitro and in a hydroponic culture. The bacterial strains have been investigated for ammonia, indole-3-acetic acid and 1-aminocyclopropane-1-carboxylate-deaminase production, phosphate solubilisation and nitrogen fixation activities. Of the tested bacteria, eight were inoculated with Triticum aestivum in a hydroponic culture. The investigated bacterial strains were found to have different plant-growth promoting activities in vitro. Under salt stress (200mM NaCl), the investigated bacterial strains significantly increased the root and shoot length and total fresh weight of the plants. The growth rates of the plants inoculated with bacterial strains ranged from 62.2% to 78.1%. Identifying of novel halophilic and halotolerant bacteria that promote plant growth can be used as alternatives for salt sensitive plants. Extensive research has been conducted on several halophilic and halotolerant bacterial strains to investigate their plant growth promoting activities. However, to the best of my knowledge, this is the first study to inoculate these bacterial strains with wheat. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Mitigation of salt stress in white clover (Trifolium repens) by Azospirillum brasilense and its inoculation effect.

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Khalid, Muhammad; Bilal, Muhammad; Hassani, Danial; Iqbal, Hafiz M N; Wang, Hang; Huang, Danfeng

2017-12-01

Salinity is one of the increasingly serious environmental problems worldwide for cultivating agricultural crops. The present study was aimed to ascertain the potential of beneficial soil bacterium Azospirillum brasilense to alleviate saline stress in Trifolium repens. Experimental plants (white clover) were grown from seeds and inoculated with or without A. brasilense bacterial strain supplemented with 0, 40, 80, or 120 mM NaCl into soil. The growth attributes including, shoot heights, root lengths, fresh and dry weights, leaf area and chlorophyll content were significantly enhanced in T. repens plants grown in A. brasilense inoculated soil than un-inoculated controls, particularly under elevated salinity conditions (40, 80 and 120 mM NaCl). Malondialdehyde content of leaf was recorded to be declined under saline conditions. Moreover, the K + /Na + ratio was also improved in bacterium-inoculated plants, since A. brasilense significantly reduced the root and shoot Na + level under high salty environment. Results revealed that soil inoculation with A. brasilense could significantly promote T. repens growth under both non-saline and saline environments, and this study might be extended to other vegetables and crops for the germination and growth enhancement.

Elemental composition of strawberry plants inoculated with the plant growth-promoting bacterium Azospirillum brasilense REC3, assessed with scanning electron microscopy and energy dispersive X-ray analysis.

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Guerrero-Molina, M F; Lovaisa, N C; Salazar, S M; Díaz-Ricci, J C; Pedraza, R O

2014-07-01

The elemental composition of strawberry plants (Fragaria ananassa cv. Macarena) inoculated with the plant growth-promoting bacterium Azospirillum brasilense REC3, and non-inoculated controls, was studied using scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) analysis. This allowed simultaneous semi-quantification of different elements in a small, solid sample. Plants were inoculated and grown hydroponically in 50% or 100% Hoagland solution, corresponding to limited or optimum nutrient medium, respectively. Bacteria-inoculated plants increased the growth index 45% and 80% compared to controls when grown in 100% and 50% Hoagland solution, respectively. Thus, inoculation with A. brasilense REC3 in a nutrient-limited medium had the strongest effect in terms of increasing both shoot and root biomass and growth index, as already described for Azospirillum inoculated into nutrient-poor soils. SEM-EDS spectra and maps showed the elemental composition and relative distribution of nutrients in strawberry tissues. Leaves contained C, O, N, Na, P, K, Ca and Cu, while roots also had Si and Cl. The organic fraction (C, O and N) accounted for over 96.3% of the total chemical composition; of the mineral fraction, Na had higher accumulation in both leaves and roots. Azospirillum-inoculated and control plants had similar elemental quantities; however, in bacteria-inoculated roots, P was significantly increased (34.33%), which constitutes a major benefit for plant nutrition, while Cu content decreased (35.16%). © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

Bacterial endophytes enhance competition by invasive plants.

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Rout, Marnie E; Chrzanowski, Thomas H; Westlie, Tara K; DeLuca, Thomas H; Callaway, Ragan M; Holben, William E

2013-09-01

Invasive plants can alter soil microbial communities and profoundly alter ecosystem processes. In the invasive grass Sorghum halepense, these disruptions are consequences of rhizome-associated bacterial endophytes. We describe the effects of N2-fixing bacterial strains from S. halepense (Rout and Chrzanowski, 2009) on plant growth and show that bacteria interact with the plant to alter soil nutrient cycles, enabling persistence of the invasive. • We assessed fluxes in soil nutrients for ∼4 yr across a site invaded by S. halepense. We assayed the N2-fixing bacteria in vitro for phosphate solubilization, iron chelation, and production of the plant-growth hormone indole-3-acetic acid (IAA). We assessed the plant's ability to recruit bacterial partners from substrates and vertically transmit endophytes to seeds and used an antibiotic approach to inhibit bacterial activity in planta and assess microbial contributions to plant growth. • We found persistent alterations to eight biogeochemical cycles (including nitrogen, phosphorus, and iron) in soils invaded by S. halepense. In this context, three bacterial isolates solubilized phosphate, and all produced iron siderophores and IAA in vitro. In growth chamber experiments, bacteria were transmitted vertically, and molecular analysis of bacterial community fingerprints from rhizomes indicated that endophytes are also horizontally recruited. Inhibiting bacterial activity with antibiotics resulted in significant declines in plant growth rate and biomass, with pronounced rhizome reductions. • This work suggests a major role of endophytes on growth and resource allocation of an invasive plant. Indeed, bacterial isolate physiology is correlated with invader effects on biogeochemical cycles of nitrogen, phosphate, and iron.

Soil microbial species loss affects plant biomass and survival of an introduced bacterial strain, but not inducible plant defences.

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Kurm, Viola; van der Putten, Wim H; Pineda, Ana; Hol, W H Gera

2018-02-12

Plant growth-promoting rhizobacteria (PGPR) strains can influence plant-insect interactions. However, little is known about the effect of changes in the soil bacterial community in general and especially the loss of rare soil microbes on these interactions. Here, the influence of rare soil microbe reduction on induced systemic resistance (ISR) in a wild ecotype of Arabidopsis thaliana against the aphid Myzus persicae was investigated. To create a gradient of microbial abundances, soil was inoculated with a serial dilution of a microbial community and responses of Arabidopsis plants that originated from the same site as the soil microbes were tested. Plant biomass, transcription of genes involved in plant defences, and insect performance were measured. In addition, the effects of the PGPR strain Pseudomonas fluorescens SS101 on plant and insect performance were tested under the influence of the various soil dilution treatments. Plant biomass showed a hump-shaped relationship with soil microbial community dilution, independent of aphid or Pseudomonas treatments. Both aphid infestation and inoculation with Pseudomonas reduced plant biomass, and led to downregulation of PR1 (salicylic acid-responsive gene) and CYP79B3 (involved in synthesis of glucosinolates). Aphid performance and gene transcription were unaffected by soil dilution. Neither the loss of rare microbial species, as caused by soil dilution, nor Pseudomonas affect the resistance of A. thaliana against M. persicae. However, both Pseudomonas survival and plant biomass respond to rare species loss. Thus, loss of rare soil microbial species can have a significant impact on both above- and below-ground organisms. © The Author(s) 2018. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Maize response to inoculation with strains of plant growth-promoting bactéria

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Janaína Dartora

Full Text Available ABSTRACT The aim of this study was to evaluate the response of maize to inoculation with strains of plant growth-promoting bacteria (PGPB in two cultivation years. The experiment was set in a randomized block design with four replicates in two cultivation years (2012/13 and 2013/14. The treatments consisted of PGPB inoculation: control (without N and without inoculation; 30 kg of N ha-1 at sowing (N1; 160 kg of N ha-1 (N1 + 130 kg of N ha-1 as top-dressing; N1 + A. brasilense, Ab-V5; N1 + A. brasilense, HM053; N1 + Azospirillum sp. L26; N1 + Azospirillum sp. L27; N1 + Enhydrobacter sp. 4331; N1 + Rhizobium sp. 8121. Basal stem diameter, plant height, leaf area, shoot dry matter and yield were evaluated. The strain of Rhizobium sp. 8121and the isolate Azospirillum sp. L26 associated with 30 kg of N ha-1 at sowing promoted yields equivalent to that of the N fertilization of 160 kg ha-1, demonstrating the potential to be used in the inoculation of maize seeds.

Effects of hybrid and bacterial inoculation on fermentation quality and fatty acid profile of barley silage.

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Kim, Dong Hyeon; Amanullah, Sadar M; Lee, Hyuk Jun; Joo, Young Ho; Han, Ouk Kyu; Adesogan, Adegbola T; Kim, Sam Churl

2018-01-01

This study estimated the effects of hybrid and bacterial inoculant on fermentation quality and fatty acid profile of barley silages. Yuyeon (Silkless) and Youngyang (Silking) barley hybrids were harvested at 24.9 and 27.1% dry matter, respectively, and chopped to 10 cm lengths. Each hybrid was treated with or without an inoculant (2 × 10 4  colony-forming units/g of Lactobacillus plantarum). A total of 48 silos were prepared in an experiment with a 2 × 2 (hybrid × inoculant) treatment arrangement with four replications and three ensiling durations (2, 7 and 100 days). After 100 days of ensiling, Yuyeon silage had higher (P hybrids and increased (P hybrid might have better potential benefits on animal performances due to its smooth awn and silkless nature, and higher in vitro dry matter digestibility. Its higher C18:3n-3 would be better for improving fatty acid profile of meat or milk than Youngyang hybrid. © 2017 Japanese Society of Animal Science.

Loblolly pine seedling growth after inoculation with plant growth-promoting rhizobacteria and ozone exposure

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Estes, B.L.; Enebak, S.A.; Chappelka, A.H. [Auburn Univ., Auburn, AL (United States). School of Forestry and Wildlife Sciences

2004-07-01

The conifer tree species with the greatest economic importance in south eastern United States plantations is Loblolly pine. Plantations require intensive fertilization, pesticide application, and irrigation. In these cases growth-promoting rhizobacteria are useful in pest control. While it was once thought that ozone in the troposphere was limited to urban areas, it is now known that it is transported far from its place of origin. Ozone is known to impact plant growth negatively. There have been no previous studies on whether growth-promoting rhizobacteria can decrease the negative effects of ozone. In this study seedlings of Loblolly pine were inoculated with either Bacillus subtilis (Ehrenberg) Cohn or Paenibacillus macerans (Schardinger) Ash. These were exposed to controlled amounts of ozone for 8-12 weeks. All plants showed decreased biomass and increased foliar damage compared to plants that were not exposed to ozone. B. subtilis inoculated plants showed less foliar damage than un-inoculated ones and root dimensions were increased. The use of growth-promoting rhizobacteria is not ready for large-scale commercial application in forestry, but this demonstration of the possible beneficial effects on ozone exposure warrants further investigation. 44 refs., 3 tabs., 2 figs.

Linkage between bacterial and fungal rhizosphere communities in hydrocarbon-contaminated soils is related to plant phylogeny.

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Bell, Terrence H; El-Din Hassan, Saad; Lauron-Moreau, Aurélien; Al-Otaibi, Fahad; Hijri, Mohamed; Yergeau, Etienne; St-Arnaud, Marc

2014-02-01

Phytoremediation is an attractive alternative to excavating and chemically treating contaminated soils. Certain plants can directly bioremediate by sequestering and/or transforming pollutants, but plants may also enhance bioremediation by promoting contaminant-degrading microorganisms in soils. In this study, we used high-throughput sequencing of bacterial 16S rRNA genes and the fungal internal transcribed spacer (ITS) region to compare the community composition of 66 soil samples from the rhizosphere of planted willows (Salix spp.) and six unplanted control samples at the site of a former petrochemical plant. The Bray-Curtis distance between bacterial communities across willow cultivars was significantly correlated with the distance between fungal communities in uncontaminated and moderately contaminated soils but not in highly contaminated (HC) soils (>2000 mg kg(-1) hydrocarbons). The mean dissimilarity between fungal, but not bacterial, communities from the rhizosphere of different cultivars increased substantially in the HC blocks. This divergence was partly related to high fungal sensitivity to hydrocarbon contaminants, as demonstrated by reduced Shannon diversity, but also to a stronger influence of willows on fungal communities. Abundance of the fungal class Pezizomycetes in HC soils was directly related to willow phylogeny, with Pezizomycetes dominating the rhizosphere of a monophyletic cluster of cultivars, while remaining in low relative abundance in other soils. This has implications for plant selection in phytoremediation, as fungal associations may affect the health of introduced plants and the success of co-inoculated microbial strains. An integrated understanding of the relationships between fungi, bacteria and plants will enable the design of treatments that specifically promote effective bioremediating communities.

Effects of water stress and inoculation with plant growth promoting rhizobacteria (PGPR on antioxidant status and photosynthetic pigments in basil (Ocimum basilicum L.

Directory of Open Access Journals (Sweden)

Mostafa Heidari

2012-01-01

Full Text Available Effects of water stress and inoculation with plant growth promoting rhizobacteria (PGPR on antioxidant activity and photosynthetic pigments were studied in basil plants. A field experiment was conducted at the University of Zabol in Iran during 2010 growing season. The experiment laid out as split plot based on randomized complete block design with three replications. Three levels of water stress W1 = 80 (control, W2 = 60 and W3 = 40% of the field capacity (FC as main plots and four levels of bacterial species consisting of S1 = Pseudomonades sp., S2 = Bacillus lentus, S3 = Azospirillum brasilens, S4 = combination of three bacterial species and S5 = control (without use of bacterial as sub plots. The results revealed that water stress caused a significant change in the antioxidant activity. The highest concentration CAT and GPX activity were in W3 treatments. By increasing water stress from control to W3, chlorophyll content in leaves was increased but Fv/Fm and APX activity decreased. Application of rhizobacteria under water stress improved the antioxidant and photosynthetic pigments in basil plants. S1 = Pseudomonades sp. under water stress, significantly increased the CAT enzyme activity, but the highest GPX and APX activity and chlorophyll content in leaves under water stress were in S4 = combination of three bacterial species.

Inheritance and identification of SCAR marker linked to bacterial wilt ...

African Journals Online (AJOL)

In the present work, the combinations (F1) were crossed between highly resistant and susceptible to bacterial wilt eggplant parents and its F2, BC1 segregation population plants were inoculated with race1 of Ralstonia solanacearum in greenhouse. In this paper, we reported that the inheritance of bacterial wilt resistance in ...

Cowpea Nodules Harbor Non-rhizobial Bacterial Communities that Are Shaped by Soil Type Rather than Plant Genotype

OpenAIRE

Leite, Jakson; Fischer, Doreen; Rouws, Luc F. M.; Fernandes-J?nior, Paulo I.; Hofmann, Andreas; Kublik, Susanne; Schloter, Michael; Xavier, Gustavo R.; Radl, Viviane

2017-01-01

Many studies have been pointing to a high diversity of bacteria associated to legume root nodules. Even though most of these bacteria do not form nodules with legumes themselves, it was shown that they might enter infection threads when co-inoculated with rhizobial strains. The aim of this work was to describe the diversity of bacterial communities associated with cowpea (Vigna unguiculata L. Walp) root nodules using 16S rRNA gene amplicon sequencing, regarding the factors plant genotype and ...

Comparison of bedside inoculation of culture media with ...

African Journals Online (AJOL)

Background: The yield of bacterial cultures from cerebrospinal fluid (CSF) at Kenyatta National Hospital (KNH) is very low. Bedside inoculation of culture media with CSF may improve yields. Objective: To compare the culture yield of CSF inoculated onto culture medium at the bedside to that of CSF inoculated onto culture ...

Differential response of kabuli and desi chickpea genotypes toward inoculation with PGPR in different soils

Science.gov (United States)

Imran, Asma; Mirza, Muhammad S.; Shah, Tariq M.; Malik, Kauser A.; Hafeez, Fauzia Y.

2015-01-01

Pakistan is among top three chickpea producing countries but the crop is usually grown on marginal lands without irrigation and fertilizer application which significantly hampers its yield. Soil fertility and inoculation with beneficial rhizobacteria play a key role in nodulation and yield of legumes. Four kabuli and six desi chickpea genotypes were, therefore, evaluated for inoculation response with IAA-producing Ochrobactrum ciceri Ca-34T and nitrogen fixing Mesorhizobium ciceri TAL-1148 in single and co-inoculation in two soils. The soil type 1 was previously unplanted marginal soil having low organic matter, P and N contents compared to soil type 2 which was a fertile routinely legume-cultivated soil. The effect of soil fertility status was pronounced and fertile soil on average, produced 31% more nodules, 62% more biomass and 111% grain yield than marginal soil. Inoculation either with O. ciceri alone or its co-inoculation with M. ciceri produced on average higher nodules (42%), biomass (31%), grains yield (64%) and harvest index (72%) in both chickpea genotypes over non-inoculated controls in both soils. Soil 1 showed maximum relative effectiveness of Ca-34T inoculation for kabuli genotypes while soil 2 showed for desi genotypes except B8/02. Desi genotype B8/02 in soil type 1 and Pb-2008 in soil type 2 showed significant yield increase as compared to respective un-inoculated controls. Across bacterial inoculation treatments, grain yield was positively correlated to growth and yield contributing parameters (r = 0.294* to 0.838*** for desi and r = 0.388* to 0.857** for kabuli). PCA and CAT-PCA analyses clearly showed a site-specific response of genotype x bacterial inoculation. Furthermore, the inoculated bacterial strains were able to persist in the rhizosphere showing colonization on root and within nodules. Present study shows that plant growth promoting rhizobacteria (PGPR) inoculation should be integrated with national chickpea breading program in

Assessing the efficacy of co-inoculation of wheat seedlings with the associative bacteria Paenibacillus polymyxa 1465 and Azospirillum brasilense Sp245.

Science.gov (United States)

Yegorenkova, Irina V; Tregubova, Kristina V; Burygin, Gennady L; Matora, Larisa Y; Ignatov, Vladimir V

2016-03-01

Co-inoculation of associative bacteria, which have high nitrogen-fixing activity, tolerance for environmental conditions, and the ability to compete with the natural microflora, is used widely to enhance the growth and yields of agricultural plants. We evaluated the ability of 2 co-inoculated plant-growth-promoting rhizobacteria, Paenibacillus polymyxa 1465 and Azospirillum brasilense Sp245, to colonize roots of wheat (Triticum aestivum L. 'Saratovskaya 29') seedlings, and we assessed the morphometric parameters of wheat early in its development. Analysis by ELISA with polyclonal antibodies raised against the exopolysaccharide of P. polymyxa 1465 and the lipopolysaccharide of A. brasilense Sp245 demonstrated that the root-colonizing activity of A. brasilense was higher when the bacterium was co-inoculated with P. polymyxa than when it was inoculated singly. Immunofluorescence microscopy with Alexa Fluor 532-labeled antibodies revealed sites of attachment of co-inoculated P. polymyxa and A. brasilense and showed that the 2 bacteria colonized similar regions of the roots. Co-inoculation exerted a negative effect on wheat seedling development, inhibiting root length by 17.6%, total root weight by 11%, and total shoot weight by 12%. Under certain conditions, dual inoculation of wheat may prove ineffective, apparently owing to the competition between the rhizobacteria for colonization sites on the plant roots. The findings from this study may aid in developing techniques for mixed bacterial inoculation of cultivated plants.

Cell viability of mycorrhiza helper bacteria solid inoculant in different carrier material

Science.gov (United States)

Asyiah, Iis Nur; Hindersah, Reginawanti; Harni, Rita

2018-02-01

Roots of food crops are colonized by nonpathogenic mycorrhizal fungi which show natural ability to control plant pathogen. Mycorrhizal establishment in plant roots is affected by rhizobacteria, known as mycorrhiza helper bacteria (MHB), which has synergetic effects on mycorrhizal associations. Laboratory experiment has been conducted to assess the best carrier material to develop well-qualified MHB of Pseudomonas diminuta and Bacillus subtilis solid inoculant. Carrier materials were 100 mesh organic matter of agricultural waste. Different spore concentration of both bacterial liquid inoculants were grown on three kinds of 100-mesh organic matter and stored at room temperature up to 90 days. Cell viability of both MHB were counted by serial dilution plate method by using specific medium. The results showed that sugar cane baggase ash was the best carrier material to maintain cell viability for both MHB. However, the population of Pseudomonas diminuta and Bacillus subtilis in sugar cane baggase ash were slightly decreased after 90 days. The use of sugarcane baggase ash for solid MHB inoculant development could be suggested.

Potency of fiber rumen bacterial isolates from local buffalo inoculated into Frisian Holstein calves during preweaning period

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Iwan Prihantoro

2012-12-01

Full Text Available Fiber-digesting bacteria are the main rumen bacteria that play an important role in digesting feed. These bacteria are adapted to low quality forage from agricultural byproduct. The aim of these study was to determine the potency of fiber-digesting bacteria consortium obtained from buffalo rumen inoculated to Frisian Holstein calves during preweaning on feed consumption, utilization, mineral uptake and physiological status. This study used 14 isolates of bacteria obtained from collection of Faculty of Animal Science, Bogor Agricultural University. The experimental unit consisted of six Frisian Holstein calves at two week old with the average body weight of 38.00 ± 6.23 kg. Calves were inoculated by 20 ml of fiber-digesting rumen bacterial isolates [4.56 x 109 cfu/ml] every morning for four weeks. Experimental design used was based on a completly randomized design with three calves received the respective inoculation (treatment group and three calves without any inoculation (control group. Data were analyzed statistically using t-test method with α = 0.05 and 0.01. The results showed that fiber-digesting bacteria (FDB from rumen buffalo have adapted in the calves rumen since preweaning periode. Inoculation FDB increased the number of rumen bacteria, digestibility of protein and P uptake calves at eight weeks old. Increased feed intake, uptake of Mg and cobalt calves at 14 weeks old. Without causing any negative effects on ADG, physiological status and rumen fermentability.

Interactive effect of biochar and plant growth-promoting bacterial endophytes on ameliorating salinity stress in maize

DEFF Research Database (Denmark)

Saleem Akhtar, Saqib; Andersen, Mathias Neumann; Naveed, Muhammad

2015-01-01

The objective of this work was to study the interactive effect of biochar and plant growth-promoting endophytic bacteria containing 1-aminocyclopropane-1-carboxylate deaminase and exopolysaccharide activity on mitigating salinity stress in maize (Zea mays L.). The plants were grown in a greenhouse...... under controlled conditions, and were subjected to separate or combined treatments of biochar (0% and 5%, w/w) and two endophytic bacterial strains (Burkholderia phytofirmans (PsJN) and Enterobacter sp. (FD17)) and salinity stress. The results indicated that salinity significantly decreased the growth...... of maize, whereas both biochar and inoculation mitigated the negative effects of salinity on maize performance either by decreasing the xylem Na+ concentration ([Na+]xylem) uptake or by maintaining nutrient balance within the plant, especially when the two treatments were applied in combination. Moreover...

The ability of the biological control agent Bacillus subtilis, strain BB, to colonise vegetable brassicas endophytically following seed inoculation

NARCIS (Netherlands)

Wulff, E.G.; Vuurde, van J.W.L.; Hockenhull, J.

2003-01-01

The ability of Bacillus subtilis, strain BB, to colonise cabbage seedlings endophytically was examined following seed inoculation. Strain BB was recovered from different plant parts including leaves (cotyledons), stem (hypocotyl) and roots. While high bacterial populations persisted in the roots and

Interactions of seedborne bacterial pathogens with host and non-host plants in relation to seed infestation and seedling transmission.

Science.gov (United States)

Dutta, Bhabesh; Gitaitis, Ronald; Smith, Samuel; Langston, David

2014-01-01

The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea) to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean) and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a null-interacting situation with the same plant species. Flowers of host and non-host plants were inoculated with 1 × 10(6) colony forming units (CFUs)/flower for each bacterial species and allowed to develop into fruits or umbels (in case of onion). Seeds harvested from each host/non-host bacterial species combination were assayed for respective bacteria by plating on semi-selective media. Additionally, seedlots for each host/non-host bacterial species combination were also assayed for pathogen transmission by seedling grow-out (SGO) assays under greenhouse conditions. The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating), respectively and they were not significantly different (P = 0.67). The percentage of seedlots infested with null-interacting bacterial species was 16.8% (by plating) and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03). None of the seedlots with incompatible/null-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively. These results indicate that the seeds of non-host plants can become infested with incompatible and null-interacting bacterial species through flower colonization and they can be transmitted via epiphytic colonization of seedlings. In addition, it was also observed that flowers and seeds of non-host plants can be colonized by

Interactions of seedborne bacterial pathogens with host and non-host plants in relation to seed infestation and seedling transmission.

Directory of Open Access Journals (Sweden)

Bhabesh Dutta

Full Text Available The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a null-interacting situation with the same plant species. Flowers of host and non-host plants were inoculated with 1 × 10(6 colony forming units (CFUs/flower for each bacterial species and allowed to develop into fruits or umbels (in case of onion. Seeds harvested from each host/non-host bacterial species combination were assayed for respective bacteria by plating on semi-selective media. Additionally, seedlots for each host/non-host bacterial species combination were also assayed for pathogen transmission by seedling grow-out (SGO assays under greenhouse conditions. The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating, respectively and they were not significantly different (P = 0.67. The percentage of seedlots infested with null-interacting bacterial species was 16.8% (by plating and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03. None of the seedlots with incompatible/null-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively. These results indicate that the seeds of non-host plants can become infested with incompatible and null-interacting bacterial species through flower colonization and they can be transmitted via epiphytic colonization of seedlings. In addition, it was also observed that flowers and seeds of non-host plants can be

Studies on phosphorus utilization as influenced by bacterial seed inoculation and phosphorus fertilization in summer mung (Vigna radiata L. Wilczek)

International Nuclear Information System (INIS)

Kothari, S.K.; Saraf, C.S.

1988-01-01

A greenhouse experiment was conducted with four types of bacterial inoculation (Rhizobium alone; Rhizobium along with Azotobacter chroococcum; Rhizobium along with Azospirillum brasilense and no inoculation) and three levels of phosphorus ( 32 P labelled SSP) application (O, 6.5 ppm and 13.0 ppm P). Inoculation with Rhizobium along with Azotobacter chroococcum was found to be better than Rhizobium alone or Rhizobium along with Azospirillum brasilense in respect of leaf, stem, root and nodule dry weight, phosphorus uptake and utilization efficiency. P application upto 6.5 ppm significantly increased leaf, stem, root and nodule dry weight and phosphorus uptake. Per cent phosphorus derived from fertilizer (per cent pdff) and fertilizer P uptake significantly increased while P utilization efficiency significantly decreased with increasing levels of P application. (author). 12 refs., 2 tables

Azotobacter chroococcum as a potentially useful bacterial biofertilizer for cotton (Gossypium hirsutum): Effect in reducing N fertilization.

Science.gov (United States)

Romero-Perdomo, Felipe; Abril, Jorge; Camelo, Mauricio; Moreno-Galván, Andrés; Pastrana, Iván; Rojas-Tapias, Daniel; Bonilla, Ruth

The aim of this research was to evaluate whether the application of two plant growth-promoting (rhizo)bacteria might reduce nitrogen fertilization doses in cotton. We used strains Azotobacter chroococcum AC1 and AC10 for their proven ability to promote seed germination and cotton growth. These microorganisms were characterized by their plant growth-promoting activities. Then, we conducted a glasshouse study to evaluate the plant growth promoting ability of these strains with reduced doses of urea fertilization in cotton. Results revealed that both strains are capable of fixing nitrogen, solubilizing phosphorus, synthesizing indole compounds and producing hydrolytic enzymes. After 12 weeks, the glasshouse experiment showed that cotton growth was positively influenced due to bacterial inoculation with respect to chemical fertilization. Notably, we observed that microbial inoculation further influenced plant biomass (p<0.05) than nitrogen content. Co-inoculation, interestingly, exhibited a greater beneficial effect on plant growth parameters compared to single inoculation. Moreover, similar results without significant statistical differences were observed among bacterial co-inoculation plus 50% urea and 100% fertilization. These findings suggest that co-inoculation of A. chroococcum strains allow to reduce nitrogen fertilization doses up to 50% on cotton growth. Our results showed that inoculation with AC1 and AC10 represents a viable alternative to improve cotton growth while decreasing the N fertilizer dose and allows to alleviate the environmental deterioration related to N pollution. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Comparison of Rumen and Manure Microbiomes and Implications for the Inoculation of Anaerobic Digesters.

Science.gov (United States)

Ozbayram, Emine Gozde; Ince, Orhan; Ince, Bahar; Harms, Hauke; Kleinsteuber, Sabine

2018-02-14

Cattle manure is frequently used as an inoculum for the start-up of agricultural biogas plants or as a co-substrate in the anaerobic digestion of lignocellulosic feedstock. Ruminal microbiota are considered to be effective plant fiber degraders, but the microbes contained in manure do not necessarily reflect the rumen microbiome. The aim of this study was to compare the microbial community composition of cow rumen and manure with respect to plant fiber-digesting microbes. Bacterial and methanogenic communities of rumen and manure samples were examined by 454 amplicon sequencing of bacterial 16S rRNA genes and mcrA genes, respectively. Rumen fluid samples were dominated by Prevotellaceae (29%), whereas Ruminococcaceae was the most abundant family in the manure samples (31%). Fibrobacteraceae (12%) and Bacteroidaceae (13%) were the second most abundant families in rumen fluid and manure, respectively. The high abundances of fiber-degrading bacteria belonging to Prevotellaceae and Fibrobacteraceae might explain the better performance of anaerobic digesters inoculated with rumen fluid. Members of the genus Methanobrevibacter were the predominant methanogens in the rumen fluid, whereas methanogenic communities of the manure samples were dominated by the candidate genus Methanoplasma . Our results suggest that inoculation or bioaugmentation with fiber-digesting rumen microbiota can enhance the anaerobic digestion of lignocellulosic biomass.

Comparison of Rumen and Manure Microbiomes and Implications for the Inoculation of Anaerobic Digesters

Directory of Open Access Journals (Sweden)

Emine Gozde Ozbayram

2018-02-01

Full Text Available Cattle manure is frequently used as an inoculum for the start-up of agricultural biogas plants or as a co-substrate in the anaerobic digestion of lignocellulosic feedstock. Ruminal microbiota are considered to be effective plant fiber degraders, but the microbes contained in manure do not necessarily reflect the rumen microbiome. The aim of this study was to compare the microbial community composition of cow rumen and manure with respect to plant fiber-digesting microbes. Bacterial and methanogenic communities of rumen and manure samples were examined by 454 amplicon sequencing of bacterial 16S rRNA genes and mcrA genes, respectively. Rumen fluid samples were dominated by Prevotellaceae (29%, whereas Ruminococcaceae was the most abundant family in the manure samples (31%. Fibrobacteraceae (12% and Bacteroidaceae (13% were the second most abundant families in rumen fluid and manure, respectively. The high abundances of fiber-degrading bacteria belonging to Prevotellaceae and Fibrobacteraceae might explain the better performance of anaerobic digesters inoculated with rumen fluid. Members of the genus Methanobrevibacter were the predominant methanogens in the rumen fluid, whereas methanogenic communities of the manure samples were dominated by the candidate genus Methanoplasma. Our results suggest that inoculation or bioaugmentation with fiber-digesting rumen microbiota can enhance the anaerobic digestion of lignocellulosic biomass.

Effects of nursery preconditioning through mycorrhizal inoculation and drought in Arbutus unedo L. plants.

Science.gov (United States)

Navarro García, Alejandra; Del Pilar Bañón Árias, Sebastián; Morte, Asunción; Sánchez-Blanco, María Jesús

2011-01-01

The influence of a water deficit treatment and mycorrhizal inoculation with Pisolithus tinctorius (Pers.) Coker and Couch on the water relations, gas exchange, and plant growth in Arbutus unedo L. plants was studied in order to evaluate the hardening process during the nursery period. The ability to withstand the adverse conditions after transplantation was also studied. Mycorrhizal and non-mycorrhizal seedlings of A. unedo were pot-grown for 4 months in a greenhouse (nursery period), during which time two irrigation treatments, well watered (100% water holding capacity, leaching 20% of the applied water) and deficit irrigation (50% of the well watered), were applied. Subsequently, the plants were transplanted to the field and well irrigated (transplanting period), after which and until the end of the experiment they received no water (establishment period). At the end of the nursery period, both water deficit and mycorrhizae were seen to have altered the plant morphology. Mycorrhizal plants had lower leaf area and improved leaf color parameters, while the water deficit increased root dry weight and the root/shoot ratio. Mycorrhizal plants had higher leaf water potential values than non-inoculated plants. Mycorrhizae increased stomatal conductance and photosynthesis values, especially in stressed plants. Drought led to an osmotic adjustment and a decrease in the leaf water potential values at turgor loss point in the mycorrhizal plants. Cell wall rigidity, measured as increased bulk modulus of elasticity, was decreased by the mycorrhizae effect. After transplanting, no differences were found in the water relations or gas exchange values between treatments. During the establishment period, the plants that had been exposed to both drought and mycorrhizae showed a better water status (higher leaf water and turgor potential values) and higher gas exchange values. In conclusion, water deficit and mycorrhizal inoculation of A. unedo plants in nursery produced changes in

Immunity to potato mop-top virus in Nicotiana benthamiana plants expressing the coat protein gene is effective against fungal inoculation of the virus.

Science.gov (United States)

Reavy, B; Arif, M; Kashiwazaki, S; Webster, K D; Barker, H

1995-01-01

Nicotiana benthamiana stem tissue was transformed with Agrobacterium tumefaciens harboring a binary vector containing the potato mop-top virus (PMTV) coat protein (CP) gene. PMTV CP was expressed in large amounts in some of the primary transformants. The five transgenic lines which produced the most CP were selected for resistance testing. Flowers on transformed plants were allowed to self-fertilize. Transgenic seedlings selected from the T1 seed were mechanically inoculated with two strains of PMTV. Virus multiplication, assayed by infectivity, was detected in only one transgenic plant of 98 inoculated. T1 plants were also highly resistant to graft inoculation; PMTV multiplied in only one plant of 45 inoculated. Transgenic T1 seedlings were challenged in a bait test in which they were grown in soil containing viruliferous spores of the vector fungus Spongospora subterranea. In these tests only two plants out of 99 became infected. Of the five transgenic lines tested, plants of three lines were immune to infection following manual, graft, or fungal inoculation.

Maize Inoculation with Azospirillum brasilense Ab-V5 Cells Enriched with Exopolysaccharides and Polyhydroxybutyrate Results in High Productivity under Low N Fertilizer Input

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André L. M. Oliveira

2017-09-01

Full Text Available Although Azospirillum strains used in commercial inoculant formulations presents diazotrophic activity, it has been reported that their ability to produce phytohormones plays a pivotal role in plant growth-promotion, leading to a general recommendation of its use in association with regular N-fertilizer doses. In addition, a high variability in the effectiveness of Azospirillum inoculants is still reported under field conditions, contributing to the adoption of the inoculation technology as an additional management practice rather than its use as an alternative practice to the use of chemical inputs in agriculture. To investigate whether the content of stress-resistance biopolymers would improve the viability and performance of Azospirillum inoculants when used as substitute of N-fertilizers, biomass of A. brasilense strain Ab-V5 enriched in exopolysaccharides (EPS and polyhydroxybutirate (PHB was produced using a new culture medium developed by factorial mixture design, and the effectiveness of resulting inoculants was evaluated under field conditions. The culture medium formulation extended the log phase of A. brasilense cultures, which presented higher cell counts and increased EPS and PHB contents than observed in the cultures grown in the OAB medium used as control. An inoculation trial with maize conducted under greenhouse conditions and using the biopolymers-enriched Ab-V5 cells demonstrated the importance of EPS and PHB to the long term bacterial viability in soil and to the effectiveness of inoculation. The effectiveness of liquid and peat inoculants prepared with Ab-V5 cells enriched with EPS and PHB was also evaluated under field conditions, using maize as target crop along different seasons, with the inoculants applied directly over seeds or at topdressing under limiting levels of N-fertilization. No additive effect on yield resulted from inoculation under high N fertilizer input, while inoculated plants grown under 80% reduction in

Maize Inoculation with Azospirillum brasilense Ab-V5 Cells Enriched with Exopolysaccharides and Polyhydroxybutyrate Results in High Productivity under Low N Fertilizer Input

Science.gov (United States)

Oliveira, André L. M.; Santos, Odair J. A. P.; Marcelino, Paulo R. F.; Milani, Karina M. L.; Zuluaga, Mónica Y. A.; Zucareli, Claudemir; Gonçalves, Leandro S. A.

2017-01-01

Although Azospirillum strains used in commercial inoculant formulations presents diazotrophic activity, it has been reported that their ability to produce phytohormones plays a pivotal role in plant growth-promotion, leading to a general recommendation of its use in association with regular N-fertilizer doses. In addition, a high variability in the effectiveness of Azospirillum inoculants is still reported under field conditions, contributing to the adoption of the inoculation technology as an additional management practice rather than its use as an alternative practice to the use of chemical inputs in agriculture. To investigate whether the content of stress-resistance biopolymers would improve the viability and performance of Azospirillum inoculants when used as substitute of N-fertilizers, biomass of A. brasilense strain Ab-V5 enriched in exopolysaccharides (EPS) and polyhydroxybutirate (PHB) was produced using a new culture medium developed by factorial mixture design, and the effectiveness of resulting inoculants was evaluated under field conditions. The culture medium formulation extended the log phase of A. brasilense cultures, which presented higher cell counts and increased EPS and PHB contents than observed in the cultures grown in the OAB medium used as control. An inoculation trial with maize conducted under greenhouse conditions and using the biopolymers-enriched Ab-V5 cells demonstrated the importance of EPS and PHB to the long term bacterial viability in soil and to the effectiveness of inoculation. The effectiveness of liquid and peat inoculants prepared with Ab-V5 cells enriched with EPS and PHB was also evaluated under field conditions, using maize as target crop along different seasons, with the inoculants applied directly over seeds or at topdressing under limiting levels of N-fertilization. No additive effect on yield resulted from inoculation under high N fertilizer input, while inoculated plants grown under 80% reduction in N fertilizer

Plant innate immunity against human bacterial pathogens

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Maeli eMelotto

2014-08-01

Full Text Available Certain human bacterial pathogens such as the enterohemorrhagic Escherichia coli and Salmonella enterica are not proven to be plant pathogens yet. Nonetheless, under certain conditions they can survive on, penetrate into, and colonize internal plant tissues causing serious food borne disease outbreaks. In this review, we highlight current understanding on the molecular mechanisms of plant responses against human bacterial pathogens and discuss salient common and contrasting themes of plant interactions with phytopathogens or human pathogens.

Plant-endophytes interaction influences the secondary metabolism in Echinacea purpurea (L.) Moench: an in vitro model.

Science.gov (United States)

Maggini, Valentina; De Leo, Marinella; Mengoni, Alessio; Gallo, Eugenia Rosaria; Miceli, Elisangela; Reidel, Rose Vanessa Bandeira; Biffi, Sauro; Pistelli, Luisa; Fani, Renato; Firenzuoli, Fabio; Bogani, Patrizia

2017-12-05

The influence of the interaction(s) between the medicinal plant Echinacea purpurea (L.) Moench and its endophytic communities on the production of alkamides is investigated. To mimic the in vivo conditions, we have set up an infection model of axenic in vitro E. purpurea plants inoculated with a pool of bacterial strains isolated from the E. purpurea stems and leaves. Here we show different alkamide levels between control (not-inoculated) and inoculated plants, suggesting that the alkamide biosynthesis may be modulated by the bacterial infection. Then, we have analysed the branched-chain amino acids (BCCA) decarboxylase gene (GenBank Accession #LT593930; the enzymatic source for the amine moiety formation of the alkamides) expression patterns. The expression profile shows a higher expression level in the inoculated E. purpurea tissues than in the control ones. These results suggest that the plant-endophyte interaction can influence plant secondary metabolism affecting the therapeutic properties of E. purpurea.

Increased heavy metal tolerance of cowpea plants by dual ...

African Journals Online (AJOL)

Through biological inoculation technology, the bacterial-mycorrhizal-legume tripartite symbiosis in artificially heavy metal polluted soil was documented and the effects of dual inoculation with arbuscular mycorrhizal (AM) fungus and Rhizobium (N-fixing bacteria, NFB) on the host plant cowpea (Vigna sinensis) in pot ...

Colonization of plants by human pathogenic bacteria in the course of organic vegetable production

Directory of Open Access Journals (Sweden)

Andreas eHofmann

2014-05-01

Full Text Available In recent years, increasing numbers of outbreaks caused by the consumption of vegetables contaminated with human pathogenic bacteria were reported. The application of organic fertilizers during vegetable production is one of the possible reasons for contamination with those pathogens. In this study laboratory experiments in axenic and soil systems following common practices in organic farming were conducted to identify the minimal dose needed for bacterial colonization of plants and to identify possible factors like bacterial species or serovariation, plant species or organic fertilizer types used, influencing the success of plant colonization by human pathogenic bacteria. Spinach and corn salad were chosen as model plants and were inoculated with different concentrations of Salmonella enterica sv. Weltevreden, Listeria monocytogenes sv. 4b and EGD-E sv. 1/2a either directly (axenic system or via agricultural soil amended with spiked organic fertilizers (soil system. In addition to PCR- and culture-based detection methods, fluorescence in situ hybridization (FISH was applied in order to localize bacteria on or in plant tissues. Our results demonstrate that shoots were colonized by the pathogenic bacteria at inoculation doses as low as 4x10CFU/ml in the axenic system or 4x105CFU/g in the soil system. In addition, plant species dependent effects were observed. Spinach was colonized more often and at lower inoculation doses compared to corn salad. Differential colonization sites on roots, depending on the plant species could be detected using FISH-CLSM analysis. Furthermore, the transfer of pathogenic bacteria to plants via organic fertilizers was observed more often and at lower initial inoculation doses when fertilization was performed with inoculated slurry compared to inoculated manure. Finally, it could be shown that by introducing a simple washing step, the bacterial contamination was reduced in most cases or even was removed completely in

Cowpea Nodules Harbor Non-rhizobial Bacterial Communities that Are Shaped by Soil Type Rather than Plant Genotype.

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Leite, Jakson; Fischer, Doreen; Rouws, Luc F M; Fernandes-Júnior, Paulo I; Hofmann, Andreas; Kublik, Susanne; Schloter, Michael; Xavier, Gustavo R; Radl, Viviane

2016-01-01

Many studies have been pointing to a high diversity of bacteria associated to legume root nodules. Even though most of these bacteria do not form nodules with legumes themselves, it was shown that they might enter infection threads when co-inoculated with rhizobial strains. The aim of this work was to describe the diversity of bacterial communities associated with cowpea ( Vigna unguiculata L. Walp) root nodules using 16S rRNA gene amplicon sequencing, regarding the factors plant genotype and soil type. As expected, Bradyrhizobium was the most abundant genus of the detected genera. Furthermore, we found a high bacterial diversity associated to cowpea nodules; OTUs related to the genera Enterobacter, Chryseobacterium, Sphingobacterium , and unclassified Enterobacteriacea were the most abundant. The presence of these groups was significantly influenced by the soil type and, to a lesser extent, plant genotype. Interestingly, OTUs assigned to Chryseobacterium were highly abundant, particularly in samples obtained from an Ultisol soil. We confirmed their presence in root nodules and assessed their diversity using a target isolation approach. Though their functional role still needs to be addressed, we postulate that Chryseobacterium strains might help cowpea plant to cope with salt stress in semi-arid regions.

Effect of Sphingobium yanoikuyae B1 inoculation on bacterial community dynamics and polycyclic aromatic hydrocarbon degradation in aged and freshly PAH-contaminated soils

International Nuclear Information System (INIS)

Cunliffe, Michael; Kertesz, Michael A.

2006-01-01

Sphingobium yanoikuyae B1 is able to degrade a range of polycyclic aromatic hydrocarbons (PAHs) and as a sphingomonad belongs to one of the dominant genera found in PAH-contaminated soils. We examined the ecological effect that soil inoculation with S. yanoikuyae B1 has on the native bacterial community in three different soils: aged PAH-contaminated soil from an industrial site, compost freshly contaminated with PAHs and un-contaminated compost. Survival of S. yanoikuyae B1 was dependent on the presence of PAHs, and the strain was unable to colonize un-contaminated compost. Inoculation with S. yanoikuyae B1 did not cause extensive changes in the native bacterial community of either soil, as assessed by denaturing gel electrophoresis, but its presence led to an increase in the population level of two other species in the aged contaminated soil community and appeared to have an antagonistic affect on several members of the contaminated compost community, indicating niche competition. - Sphingobium yanoikuyae B1 does not cause major changes in the native bacterial community while colonizing PAH-contaminated soils, but some niche competition is evident

Characterization of plant growth-promoting traits of free-living diazotrophic bacteria and their inoculation effects on growth and nitrogen uptake of crop plants.

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Islam, Md Rashedul; Madhaiyan, M; Deka Boruah, Hari P; Yim, Woojong; Lee, Gillseung; Saravanan, V S; Fu, Qingling; Hu, Hongqing; Sa, Tongmin

2009-10-01

The search for diverse plant growth-promoting (PGP) diazotrophic bacteria is gaining momentum as efforts are made to exploit them as biofertilizers for various economically important crops. In the present study, 17 diazotrophic strains belonging to eight different genera isolated from rice paddy fields were screened for multiple PGP traits and evaluated for their inoculation effects on canola and rice plants. All of the strains tested positive for 1- aminocyclopropane-1-carboxylate (ACC) deaminase activity and production of indole 3-acetic acid (IAA) and ammonia (NH3). Additionally, four of the strains were able to solubilize phosphorus (P), five tested positive for zinc (Zn) solubilization and sulfur (S) oxidation, and eight strains produced siderophores. Based on the presence of multiple PGP traits, 10 strains were selected for inoculation studies. Treatment with Herbaspirillum sp. RFNB26 resulted in maximum root length (54.3%), seedling vigor, and dry biomass in canola, whereas Paenibacillus sp. RFNB4 exhibited the lowest activity under gnotobiotic conditions. However, under pot culture conditions, Paenibacillus sp. RFNB4 significantly increased plant height and dry biomass production by 42.3% and 29.5%, respectively. Canola plants and rhizosphere soils inoculated with Bacillus sp. RFNB6 exhibited significantly higher nitrogenase activity. In greenhouse experiments, Serratia sp. RFNB18 increased rice plant height by 35.1%, Xanthomonas sp. RFNB24 enhanced biomass production by 84.6%, and rice rhizosphere soils inoculated with Herbaspirillum sp. RFNB26 exhibited the highest nitrogenase activity. Our findings indicate that most of the selected strains possess multiple PGP properties that significantly improve the growth parameters of the two plants when tested under controlled conditions.

Microbial Inoculants and Their Impact on Soil Microbial Communities: A Review

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Darine Trabelsi

2013-01-01

Full Text Available The knowledge of the survival of inoculated fungal and bacterial strains in field and the effects of their release on the indigenous microbial communities has been of great interest since the practical use of selected natural or genetically modified microorganisms has been developed. Soil inoculation or seed bacterization may lead to changes in the structure of the indigenous microbial communities, which is important with regard to the safety of introduction of microbes into the environment. Many reports indicate that application of microbial inoculants can influence, at least temporarily, the resident microbial communities. However, the major concern remains regarding how the impact on taxonomic groups can be related to effects on functional capabilities of the soil microbial communities. These changes could be the result of direct effects resulting from trophic competitions and antagonistic/synergic interactions with the resident microbial populations, or indirect effects mediated by enhanced root growth and exudation. Combination of inoculants will not necessarily produce an additive or synergic effect, but rather a competitive process. The extent of the inoculation impact on the subsequent crops in relation to the buffering capacity of the plant-soil-biota is still not well documented and should be the focus of future research.

Enhanced fertilization effect of a compost obtained from mixed herbs waste inoculated with novel strains of mesophilic bacteria

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Dimitrijević Snežana M.

2017-01-01

Full Text Available Mixed medicinal plant waste was composted with addition of novel bacterial strains belonging to the genera Streptomyces, Paenybacillus, Bacillus and Hymenobacter. The composting was followed by assessment of chemical and biological parameters including C/N ratio, loss of organic matter, phosphorous and potassium content as well as CO2 generation and dehydrogenase activity during 164 days. The selected mesophilic bacterial starters had a potential to significantly reduce the period of mixed herb waste decomposition, from about 6 months to about 2.5 months. Based on the seed germination index of four plants (Fagopirum esculentum, Thymus vulgaris, Cynara scolimus and Lavandula officinalis the germination and radial root growth of the investigated plants was improved by the inoculated compost. The germination index of all tested species on the mature inoculated composts was in average 60% higher compared to the control compost. The research indicates that the mesophilic starter addition into the herbs waste can contribute to the speed of waste decomposition and lead to the improvement of biofertilization effect of the obtained compost. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR 31035

Does mycorrhizal inoculation benefit plant survival, plant development and small-scale soil fixation? Results from a perennial eco-engineering field experiment in the Swiss Alps.

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Bast, Alexander; Grimm, Maria; Graf, Frank; Baumhauer, Roland; Gärtner, Holger

2015-04-01

In mountain environments superficial slope failures on coarse grained, vegetation-free slopes are common processes and entail a certain risk for humans and socio-economic structures. Eco-engineering measures can be applied to mitigate slope instabilities. In this regard, limited plant survival and growth can be supported by mycorrhizal inoculation, which was successfully tested in laboratory studies. However, related studies on a field scale are lacking. Furthermore, mycorrhizae are known to enhance soil aggregation, which is linked to soil physics such as shear strength, and hence it is a useful indicator for near-surface soil/slope stability. The overall objective of our contribution was to test whether mycorrhizal inoculation can be used to promote eco-engineering measures in steep alpine environments based on a five-year field experiment. We hypothesized that mycorrhizal inoculation (i) enhances soil aggregation, (ii) stimulate plant survival and fine root development, (iii) effects plant performance, (iv) the stimulated root development in turn influences aggregate stability, and (v) that climatic variations play a major role in fine-root development. We established mycorrhizal and non-mycorrhizal treated eco-engineered research plots (hedge layers mainly consisting of Alnus spp. and Salix spp.) on a field experimental scale. The experimental site is in the eastern Swiss Alps at an erosion-prone slope where many environmental conditions can be seen as homogeneous. Soil aggregation, fine root development and plant survival was quantified at the end of four growing seasons (2010, '11, '12, '14). Additionally, growth properties of Alnus spp. and Salix spp. were measured and their biomass estimated. Meteorological conditions, soil temperature and soil water content were recorded. (i) The introduced eco-engineering measures enhanced aggregate stability significantly. In contrast to published greenhouse and laboratory studies, mycorrhizal inoculation delayed soil

Application of Endophytic Pseudomonas fluorescens and a Bacterial Consortium to Brassica napus Can Increase Plant Height and Biomass under Greenhouse and Field Conditions

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Richard D. Lally

2017-12-01

Full Text Available Plant associated bacteria with plant growth promotion (PGP properties have been proposed for use as environmentally friendly biofertilizers for sustainable agriculture; however, analysis of their efficacy in the field is often limited. In this study, greenhouse and field trials were carried out using individual endophytic Pseudomonas fluorescens strains, the well characterized rhizospheric P. fluorescens F113 and an endophytic microbial consortium of 10 different strains. These bacteria had been previously characterized with respect to their PGP properties in vitro and had been shown to harbor a range of traits associated with PGP including siderophore production, 1-aminocyclopropane-1-carboxylic acid (ACC deaminase activity, and inorganic phosphate solubilization. In greenhouse experiments individual strains tagged with gfp and Kmr were applied to Brassica napus as a seed coat and were shown to effectively colonize the rhizosphere and root of B. napus and in addition they demonstrated a significant increase in plant biomass compared with the non-inoculated control. In the field experiment, the bacteria (individual and consortium were spray inoculated to winter oilseed rape B. napus var. Compass which was grown under standard North Western European agronomic conditions. Analysis of the data provides evidence that the application of the live bacterial biofertilizers can enhance aspects of crop development in B. napus at field scale. The field data demonstrated statistically significant increases in crop height, stem/leaf, and pod biomass, particularly, in the case of the consortium inoculated treatment. However, although seed and oil yield were increased in the field in response to inoculation, these data were not statistically significant under the experimental conditions tested. Future field trials will investigate the effectiveness of the inoculants under different agronomic conditions.

INOCULATION AND ISOLATION OF PLANT GROWTH-PROMOTING BACTERIA IN MAIZE GROWN IN VITÓRIA DA CONQUISTA, BAHIA, BRAZIL

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Joelma da Silva Santos

2015-02-01

Full Text Available Maize is among the most important crops in the world. This plant species can be colonized by diazotrophic bacteria able to convert atmospheric N into ammonium under natural conditions. This study aimed to investigate the effect of inoculation of the diazotrophic bacterium Herbaspirillum seropedicae (ZAE94 and isolate new strains of plant growth-promoting bacteria in maize grown in Vitória da Conquista, Bahia, Brazil. The study was conducted in a greenhouse at the Experimental Area of the Universidade Estadual do Sudoeste da Bahia. Inoculation was performed with peat substrate, with and without inoculation containing strain ZAE94 of H. seropedicae and four rates of N, in the form of ammonium sulfate (0, 60, 100, and 140 kg ha-1 N. After 45 days, plant height, dry matter accumulation in shoots, percentage of N, and total N (NTotal were evaluated. The bacteria were isolated from root and shoot fragments of the absolute control; the technique of the most probable number and identification of bacteria were used. The new isolates were physiologically characterized for production of indole acetic acid (IAA and nitrogenase activity. We obtained 30 isolates from maize plants. Inoculation with strain ZAE94 promoted an increase of 14.3 % in shoot dry mass and of 44.3 % in NTotal when associated with the rate 60 kg ha-1 N. The strains N11 and N13 performed best with regard to IAA production and J06, J08, J10, and N15 stood out in acetylene reduction activity, demonstrating potential for inoculation of maize.

Effects of silicon treatment and inoculation with Fusarium oxysporum f. sp. vasinfectum on cellular defences in root tissues of two cotton cultivars.

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Whan, Jennifer A; Dann, Elizabeth K; Aitken, Elizabeth A B

2016-08-01

Silicon has been shown to enhance the resistance of plants to fungal and bacterial pathogens. Here, the effect of potassium silicate was assessed on two cotton (Gossypium hirsutum) cultivars subsequently inoculated with Fusarium oxysporum f. sp. vasinfectum (Fov). Sicot 189 is moderately resistant whilst Sicot F-1 is the second most resistant commercial cultivar presently available in Australia. Transmission and light microscopy were used to compare cellular modifications in root cells after these different treatments. The accumulation of phenolic compounds and lignin was measured. Cellular alterations including the deposition of electron-dense material, degradation of fungal hyphae and occlusion of endodermal cells were more rapidly induced and more intense in endodermal and vascular regions of Sicot F-1 plants supplied with potassium silicate followed by inoculation with Fov than in similarly treated Sicot 189 plants or in silicate-treated plants of either cultivar not inoculated with Fov. Significantly more phenolic compounds were present at 7 d post-infection (dpi) in root extracts of Sicot F-1 plants treated with potassium silicate followed by inoculation with Fov compared with plants from all other treatments. The lignin concentration at 3 dpi in root material from Sicot F-1 treated with potassium silicate and inoculated with Fov was significantly higher than that from water-treated and inoculated plants. This study demonstrates that silicon treatment can affect cellular defence responses in cotton roots subsequently inoculated with Fov, particularly in Sicot F-1, a cultivar with greater inherent resistance to this pathogen. This suggests that silicon may interact with or initiate defence pathways faster in this cultivar than in the less resistant cultivar. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Effects of Bacterial Inoculants and Absorbents on Fermentation Properties and Chemical Composition of Fresh Sugar Beet Pulp Silage Using Laboratory silos

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Saeid Seidali Dolat-Abad

2016-04-01

Full Text Available Introduction Ensiling is one of the common preserving methods for forage or other organic materials. In this method, organic matters were preserved by proving an aerobic condition and then by reducing the pH with increasing acids production (mainly lactic acid. Some circumstances like enough soluble carbohydrates, low buffering capacity and appropriate dry matter concentration are needed in ensilages for an ideal silage production. Seepage production during ensiling is one of the most problems especially when high moisture materials (like fresh beet sugar pulp are ensiled. Silage seepage can pollute the environment and make loses in nutrients like soluble carbohydrates, protein, organic acids and etc. Moreover, lactic acid bacteria inoculants (Mainly consist of Lactobacillus plantarum have been widely used for improving fermentation pattern in ensilages. These external provided bacteria usually enhance lactic acid production in silage and then accelerate the falling of pH values in silages. Rapid decrease in pH can inhibit non-beneficial bacteria from activity which finally preserves nutrients from un-necessary fermentation or oxidation. The aim of this study was to investigate the interactive effects of lactic acid bacteria inoculants and some absorbents (straw and pith on chemical properties and fermentation profile of wet sugar beet pulp silage. Materials and Methods In the first experiment, fresh wet sugar beet pulp was treated with 5% straw or 5% pith in order to investigate the effects of these absorbents on chemical composition, fermentation characteristics and effluent production during ensiling period. In the second experiment, fresh wet sugar beet pulp was treated with a commercial lactic acid bacteria inoculants (Ecosyle and/or 5% pith in order to investing the main and interaction effects of the bacterial bacteria inoculants and the best absorbents from the experiment 1. In both experiments, triplicate samples were prepared for each

Bacterial exopolysaccharide and biofilm formation stimulate chickpea growth and soil aggregation under salt stress

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Aisha Waheed Qurashi

2012-09-01

Full Text Available To compensate for stress imposed by salinity, biofilm formation and exopolysaccharide production are significant strategies of salt tolerant bacteria to assist metabolism. We hypothesized that two previously isolated salt-tolerant strains Halomonas variabilis (HT1 and Planococcus rifietoensis (RT4 have an ability to improve plant growth, These strains can form biofilm and accumulate exopolysacharides at increasing salt stress. These results showed that bacteria might be involved in developing microbial communities under salt stress and helpful in colonizing of bacterial strains to plant roots and soil particles. Eventually, it can add to the plant growth and soil structure. We investigated the comparative effect of exopolysacharide and biofilm formation in two bacterial strains Halomonas variabilis (HT1 and Planococcus rifietoensis (RT4 in response to varying salt stress. We found that biofilm formation and exopolysaccharide accumulation increased at higher salinity. To check the effect of bacterial inoculation on the plant (Cicer arietinum Var. CM-98 growth and soil aggregation, pot experiment was conducted by growing seedlings under salt stress. Inoculation of both strains increased plant growth at elevated salt stress. Weight of soil aggregates attached with roots and present in soil were added at higher salt concentrations compared to untreated controls. Soil aggregation was higher at plant roots under salinity. These results suggest the feasibility of using above strains in improving plant growth and soil fertility under salinity.

EFECT OF THE INOCULATION OF Rhodococcus fascians AND Azospirillum halopraeferens IN GERMINATION OF PALO FIERRO (Olneya tesota A. Gray UNDER GREENHOUSE CONDITIONS

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Edgar Omar Rueda Puente

2017-05-01

Full Text Available The growth-promoting bacteria in plants (BGPB are a group of different species of bacteria can increase plant growth and productivity. Which can benefit plants through their own bacterial metabolism (phosphate solubilizing, producing hormones or fixing nitrogen. At present, desertification is a growing phenomenon worldwide, afforestation is one of the common solutions to combat this problem. Trees for reforestation are initially grown in greenhouses or nurseries. Among numerous reforestation practices, there is an alternative that inoculation with PGPB. Is a forest species that is endemic Olneya tesota Sonoran Desert, which is in danger of extinction. The objective was to evaluate the effect of bacteria growth promoter in plants with Rhodococcuis fascians and Azospirillum halopraeferens on germination and emergence of Ironwood under four salt concentrations (0, 0.25, 0.5 and 0.75 M NaCl under greenhouse conditions. Were obtained ironwood seeds in the region of Santa Ana, Sonora. Under greenhouse conditions was evaluated emergence percentage, germination rate, height, plant root length, fresh and dry weight of plant, number of bacterial cells attached to the root system, fresh and dry weight of the root. The results indicate that the germination percentage and other variables evaluated decreased as salinity increases. However, these changed positively to inoculation with bacteria R. fascians and A. halopraeferens.

Cowpea Nodules Harbor Non-rhizobial Bacterial Communities that Are Shaped by Soil Type Rather than Plant Genotype

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Leite, Jakson; Fischer, Doreen; Rouws, Luc F. M.; Fernandes-Júnior, Paulo I.; Hofmann, Andreas; Kublik, Susanne; Schloter, Michael; Xavier, Gustavo R.; Radl, Viviane

2017-01-01

Many studies have been pointing to a high diversity of bacteria associated to legume root nodules. Even though most of these bacteria do not form nodules with legumes themselves, it was shown that they might enter infection threads when co-inoculated with rhizobial strains. The aim of this work was to describe the diversity of bacterial communities associated with cowpea (Vigna unguiculata L. Walp) root nodules using 16S rRNA gene amplicon sequencing, regarding the factors plant genotype and soil type. As expected, Bradyrhizobium was the most abundant genus of the detected genera. Furthermore, we found a high bacterial diversity associated to cowpea nodules; OTUs related to the genera Enterobacter, Chryseobacterium, Sphingobacterium, and unclassified Enterobacteriacea were the most abundant. The presence of these groups was significantly influenced by the soil type and, to a lesser extent, plant genotype. Interestingly, OTUs assigned to Chryseobacterium were highly abundant, particularly in samples obtained from an Ultisol soil. We confirmed their presence in root nodules and assessed their diversity using a target isolation approach. Though their functional role still needs to be addressed, we postulate that Chryseobacterium strains might help cowpea plant to cope with salt stress in semi-arid regions. PMID:28163711

Molecular detection of Erwinia psidii in guava plants under greenhouse and field conditions

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Claudênia Ferreira da Silva

2016-09-01

Full Text Available ABSTRACT: Erwinia psidii causes bacterial blight of guava ( Psidium guajava , an important disease of this crop in Brazil. The pathogen affects branches and twigs of guava trees, reducing yield significantly. Bacterial dissemination often occurs through contaminated but asymptomatic propagating plant material. The objectives of this research were to evaluate the use of BIO-PCR and conventional PCR to detect E. psidii in inoculated guava plants grown in a greenhouse and in symptomatic and asymptomatic trees from guava orchards. Erwinia psidii strain IBSBF 1576 was inoculated (107CFU mL-1 into young guava shoots and plant tissue was analysed at 0, 5, 10, and 15 days after inoculation. Symptoms were observed after 5 days and all inoculated shoots were PCR positive at all times, by both BIO-PCR and conventional PCR. Under natural infection conditions, 40 samples were tested by BIO-PCR from each of three guava orchards, 20 showing symptoms and 20 asymptomatic. PCR was positive for 58 out of 60 symptomatic samples (96.7% and for 6.7% of asymptomatic samples, showing that the method can be used to detect the pathogen at early stages of infection. This PCR method may be used as a diagnostic tool to assess bacterial survival, dissemination and disease outbreaks.

[Processes of plant colonization by Methylobacterium strains and some bacterial properties ].

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Romanovskaia, V A; Stoliar, S M; Malashenko, Iu R; Dodatko, T N

2001-01-01

The pink-pigmented facultative methylotrophic bacteria (PPFMB) of the genus Methylobacterium are indespensible inhabitants of the plant phyllosphere. Using maize Zea mays as a model, the ways of plant colonization by PPFMB and some properties of the latter that might be beneficial to plants were studied. A marked strain, Methylobacterium mesophilicum APR-8 (pULB113), was generated to facilitate the detection of the methylotrophic bacteria inoculated into the soil or applied to the maize leaves. Colonization of maize leaves by M. mesophilicum APR-8 (pULB113) occurred only after the bacteria were applied onto the leaf surface. In this case, the number of PPFMB cells on inoculated leaves increased with plant growth. During seed germination, no colonization of maize leaves with M. mesophilicum cells occurred immediately from the soil inoculated with the marked strain. Thus, under natural conditions, colonization of plant leaves with PPFMB seems to occur via soil particle transfer to the leaves by air. PPFMB monocultures were not antagonistic to phytopathogenic bacteria. However, mixed cultures of epiphytic bacteria containing Methylobacterium mesophilicum or M. extorquens did exhibit an antagonistic effect against the phytopathogenic bacteria studied (Xanthomonas camprestris, Pseudomonas syringae, Erwinia carotovora, Clavibacter michiganense, and Agrobacterium tumifaciens). Neither epiphytic and soil strains of Methylobacterium extorquens, M. organophillum, M. mesophilicum, and M. fujisawaense catalyzed ice nucleation. Hence, they cause no frost injury to plants. Thus, the results indicate that the strains of the genus Methylobacterium can protect plants against adverse environmental factors.

Using common mycorrhizal networks for controlled inoculation of Quercus spp. with Tuber melanosporum: the nurse plant method.

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Pereira, Guillermo; Palfner, Götz; Chávez, Daniel; Suz, Laura M; Machuca, Angela; Honrubia, Mario

2013-07-01

The high cost and restricted availability of black truffle spore inoculum for controlled mycorrhiza formation of host trees produced for truffle orchards worldwide encourage the search for more efficient and sustainable inoculation methods that can be applied globally. In this study, we evaluated the potential of the nurse plant method for the controlled inoculation of Quercus cerris and Quercus robur with Tuber melanosporum by mycorrhizal networks in pot cultures. Pine bark compost, adjusted to pH 7.8 by liming, was used as substrate for all assays. Initially, Q. robur seedlings were inoculated with truffle spores and cultured for 12 months. After this period, the plants presenting 74 % mycorrhizal fine roots were transferred to larger containers. Nurse plants were used for two treatments of two different nursling species: five sterilized acorns or five 45-day-old, axenically grown Q. robur or Q. cerris seedlings, planted in containers around the nurse plant. After 6 months, colonized nursling plant root tips showed that mycorrhiza formation by T. melanosporum was higher than 45 % in the seedlings tested, with the most successful nursling combination being Q. cerris seedlings, reaching 81 % colonization. Bulk identification of T. melanosporum mycorrhizae was based on morphological and anatomical features and confirmed by sequencing of the internal transcribed spacer region of the ribosomal DNA of selected root tips. Our results show that the nurse plant method yields attractive rates of mycorrhiza formation by the Périgord black truffle and suggest that establishing and maintaining common mycorrhizal networks in pot cultures enables sustained use of the initial spore inoculum.

Hydrocarbon degradation and plant colonization of selected bacterial strains isolated from the rhizsophere and plant interior of Italian ryegrass and Birdsfoot trefoil

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Sohail, Y.; Andria, V.; Reichenauer, T. G.; Sessitsch, A.

2009-04-01

Hydrocarbon-degrading strains were isolated from the rhizosphere, root and shoot interior of Italian ryegrass (Lolium multiflorum var. Taurus), Birdsfoot trefoil (Lotus corniculatus var. Leo) grown in a soil contaminated with petroleum oil. Strains were tested regarding their phylogeny and their degradation efficiency. The most efficient strains were tested regarding their suitability to be applied for phytoremediation of diesel oils. Sterilized and non-sterilized agricultural soil, with and with out compost, were spiked with diesel and used for planting Italian ryegrass and birdsfoot trefoil. Four selected strains with high degradation activities, derived from the rhizosphere and plant interior, were selected for individual inoculation. Plants were harvested at flowering stage and plant biomass and hydrocarbon degradation was determined. Furthermore, it was investigated to which extent the inoculant strains were able to survive and colonize plants. Microbial community structures were analysed by 16S rRNA and alkB gene analysis. Results showed efficient colonization by the inoculant strains and improved degradation by the application of compost combined with inoculation as well as on microbial community structures will be presented.

Lactating cow response to lucerne silage inoculated with Lactobacillus plantarum

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It is unclear why bacterial silage inoculants improve milk production in lactating dairy cattle. However, recent in vitro results suggest that inoculated silage effects on milk production may be tied to greater production of rumen microorganisms. Our objective was to determine if alfalfa silage trea...

Co-existence of Rhizobia and Diverse Non-rhizobial Bacteria in the Rhizosphere and Nodules of Dalbergia odorifera Seedlings Inoculated with Bradyrhizobium elkanii, Rhizobium multihospitium–Like and Burkholderia pyrrocinia–Like Strains

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Junkun Lu

2017-11-01

Full Text Available Rhizobia induce root nodules and fix atmospheric N2 for most legume species in exchange for carbon. However, the diverse endophytic non-rhizobial bacteria in legume nodules that co-exist with rhizobia are often ignored because they are difficult to cultivate using routine cultivation approaches. To enhance our understanding of the incidence and diversity of legume–bacteria associations, a high-throughput sequencing analysis of bacterial 16S rRNA genes was used to examine the bacterial community in the rhizospheres and root nodules of Dalbergia odorifera seedlings that were uninoculated or inoculated with Bradyrhizobium elkanii H255, Rhizobium multihospitium–like HT221, or Burkholderia pyrrocinia–like H022238, in two growth media (nitrogen [N]-supplied soil or N-omitted potting mix. Seedlings inoculated with Bradyrhizobium had significantly more nodules than seedlings in the other inoculation conditions, regardless of growth media. Using the 15N natural abundance method, it was shown that the inoculated plants had significantly higher N2 fixation efficiency (48–57% and specific nodule activity [269–313 μg N mg−1 of dry weight (dwt nodule] compared to the uninoculated plants (203 μg N mg−1 dwt nodule. The 16S rRNA gene analysis showed that there was generally a higher bacterial diversity in the rhizosphere than in the nodules in the corresponding condition. Both rhizobial inoculation and media status significantly altered the bacterial communities in the rhizospheres and nodules (P < 0.05, with the exception of the inoculated soil rhizospheres. Regarding non-rhizobial bacteria, three genera, i.e., Lactococcus, Bacillus, and Pseudomonas, were consistently enriched in the rhizosphere and Bradyrhizobium, Chloroplast norank (which belongs to Cyanobacteria, and Lactococcus were commonly found in the nodules. In contrast, common rhizobial genera (including Rhizobium, Mesorhizobium, and Burkholderia were only present in the nodules at low

Effect of Rhizobium and Phosphate Solubilizing Bacterial Inoculants on Symbiotic Traits, Nodule Leghemoglobin, and Yield of Chickpea Genotypes

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G. S. Tagore

2013-01-01

Full Text Available A field experiment was carried out during the rabi season of 2004-05 to find out the effect of Rhizobium and phosphate solubilizing bacterial (PSB inoculants on symbiotic traits, nodule leghemoglobin, and yield of five elite genotypes of chickpea. Among the chickpea genotypes, IG-593 performed better in respect of symbiotic parameters including nodule number, nodule fresh weight, nodule dry weight, shoot dry weight, yield attributes and yield. Leghemoglobin content (2.55 mg g−1 of fresh nodule was also higher under IG-593. Among microbial inoculants, the Rhizobium + PSB was found most effective in terms of nodule number (27.66 nodules plant−1, nodule fresh weight (144.90 mg plant−1, nodule dry weight (74.30 mg plant−1, shoot dry weight (11.76 g plant−1, and leghemoglobin content (2.29 mg g−1 of fresh nodule and also showed its positive effect in enhancing all the yield attributing parameters, grain and straw yields.

Peanut plant growth and yield as influenced by co-inoculation with Bradyrhizobium and some rhizo-microorganisms under sandy loam soil conditions

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F.Sh.F. Badawi

2011-06-01

Full Text Available The ability of tested rhizomicrobial isolates (Serratia marcescens and Trichoderma harzianum along with a strain of root nodule bacteria (Bradyrhizobium spp. to exhibit some PGP-properties was evaluated in vitro conditions. The main PGP-properties, namely the ability to solubilize-P and production of IAA, as well as production of siderophores and HCN were examined. Additionally, field trials were conducted on sandy loam soil at El-Tahrir Province during two successive summer seasons to study the effect of co-inoculation with Bradyrhizobium either individually or together with S. marcescens and/or T. harzianum on nodulation, some plant growth characters, peanut yield and its yield components. The in vitro experiment revealed that all of the tested microorganisms were apparently able to trigger PGP-properties. Phosphate solubilization was the common feature of the employed microorganisms. However, T. harzianum appeared to be superior to other microorganisms, and Bradyrhizobium displayed the lowest capacity. The ability of the microorganisms to produce indole compounds showed that S. marcescens was more effective in IAA production and followed by Bradyrhizobium. Capacity of S. marcescens and T. harzianum to excrete ferric-specific ligands (siderophores and HCN was detected, while Bradyrhizobium failed to produce such compounds. Results of field trials showed that the uninoculated peanut had the least nodulation status, N2-ase activity and all vegetative growth characters in both studied seasons. Bacterization of peanut seeds with bradyrhizobia exerted considerable improvement in number and mass of root nodules, increased the rate of acetylene reduction and all growth characters in comparison to the uninoculated control. The synergy inoculation between bradyrhizobia and any of the tested microorganisms led to further increases of all mentioned characters and strengthened the stimulating effect of the bacterial inoculation. However, the promotive

Effects of Nano-Zinc oxide and Seed Inoculation by Plant Growth Promoting Rhizobacteria (PGPR on Yield, Yield Components and Grain Filling Period of Soybean (Glycine max L.

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R. Seyed Sharifi

2016-02-01

Full Text Available Introduction Utilizing biological fertilizer is a proper and cheap method for crop production. Potentially, soybean can be used as biological fertilizers and seed inoculation. Zinc is an essential element that have positive effects on plant growth and its development. Canola, sunflower, soybean and safflower are the main cultivated oilseeds in Iran. Soybean production in Iran is very low as compared to other countries. One of the most effective factor in increasing the soybean yield is seed inoculation with plant growth promoting rhizobacteria (PGPR and application of Zinc fertilizer. Some of the benefits provided by PGPR are the ability to produce gibberellic acid, cytokinins and ethylene, N2 fixation, solubilization of mineral phosphates and other nutrients (56. Numerous studies have shown a substantial increase in dry matter accumulation and seed yield following inoculation with PGPR. Seyed Sharifi (45 reported that seed inoculation with Azotobacter chroococcum strain 5 increased all of the growth indices such as total dry matter, crop growth rate and relative growth rate. Increasing and extending the role of biofertilizers such as Rhizobium can reduce the need for chemical fertilizers and decrease adverse environmental effects. Therefore, in the development and implementation of sustainable agricultural techniques, biofertilization has great importance in alleviating environmental pollution and deterioration of the nature. As a legume, soybean can obtain a significant portion (4-85% of its nitrogen requirement through symbiotic N2 fixation when grown in association with effective and compatible Rhizobium strains. Since there is little available information on nano-zinc oxide and seed inoculation by plant growth promoting rhizobacteria (PGPR on yield in the agro-ecological growing zones of Ardabil province of Iran. Therefore, this research was conducted to investigate the effects of nano-zinc oxide and seed inoculation with plant growth

Co-inoculation effects of Bradyrhizobium japonicum and ...

African Journals Online (AJOL)

Corporate Edition

2013-05-15

. 2851. MATERIALS AND METHODS. Bacterial strains, media and growth conditions. Two B. japonicum strains of CB 1809 and USDA 110 those currently used in rhizobial inoculants production for soybean at the. Department ...

Promoting effects of a single Rhodopseudomonas palustris inoculant on plant growth by Brassica rapa chinensis under low fertilizer input.

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Wong, Wai-Tak; Tseng, Ching-Han; Hsu, Shu-Hua; Lur, Huu-Sheng; Mo, Chia-Wei; Huang, Chu-Ning; Hsu, Shu-Chiung; Lee, Kung-Ta; Liu, Chi-Te

2014-09-17

Several Rhodopseudomonas palustris strains have been isolated from rice paddy fields in Taiwan by combining the Winogradsky column method and molecular marker detection. These isolates were initially screened by employing seed germination and seedling vigor assays to evaluate their potential as inoculants. To fulfill the demand in the present farming system for reducing the application of chemical fertilizers, we assessed the plant growth-promoting effects of the R. palustris YSC3, YSC4, and PS3 inoculants on Brassica rapa chinensis (Chinese cabbage) cultivated under a half quantity of fertilizer. The results obtained showed that supplementation with approximately 4.0×10(6) CFU g(-1) soil of the PS3 inoculant at half the amount of fertilizer consistently produced the same plant growth potential as 100% fertility, and also increased the nitrogen use efficiency of the applied fertilizer nutrients. Furthermore, we noted that the plant growth-promotion rate elicited by PS3 was markedly higher with old seeds than with new seeds, suggesting it has the potential to boost the development of seedlings that were germinated from carry-over seeds of poor quality. These beneficial traits suggest that the PS3 isolate may serve as a potential PGPR inoculant for integrated nutrient management in agriculture.

Increased root exudation of 14C-compounds by sorghum seedlings inoculated with nitrogen-fixing bacteria

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Lee, K.J.; Gaskins, M.H.

1982-01-01

Organic components leaked from Sorghum bicolor seedlings ('root exudates') were examined by recovering 14 C labelled compounds from root solutions of seedlings inoculated with Azospirillum brasilense, Azotobacter vinelandii or Klebsiella pneumoniae nif-. Up to 3.5% of the total 14 C recovered from shoots, roots, and nutrient solutions was found in the root solutions. Inoculation with Azospirillum and Azotobacter increased the amounts of 14 C and decreased the amounts of carbohydrates in the root solutions. When sucrose was added as a carbon source for the bacteria, the increase of 14 C in the solutions did not occur. Quantities of 14 C found in the root solutions were proportional to amounts of mineral nitrogen supplied to the plants. Bacterial growth also was proportional to nitrogen levels. When sorghum plants were grown in soil and labelled with 14 CO 2 , about 15% of the total 14 C recovered within 48 hours exposure was found in soil leachates. (orig.)

Endophytic Streptomyces spp. as Biocontrol Agents of Rice Bacterial Leaf Blight Pathogen (Xanthomonas oryzae pv. oryzae

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RATIH DEWI HASTUTI

2012-12-01

Full Text Available Xanthomonas oryzae pv. oryzae (Xoo, a causal agent of bacterial leaf blight (BLB, is one of the most important pathogens of rice. The effectiveness of ten Streptomyces spp. isolates in suppressing Xoo disease was assessed in planta and in vitro. In planta experiments were carried out in a greenhouse and arranged in a randomized completely block design (RCBD with three replications. Twenty treatments were tested which included plants inoculated with both Streptomyces spp. and Xoo, and plants inoculated with only Streptomyces spp. Plants inoculated with Xoo and sprayed with a chemical bactericide, and plants inoculated with only Xoo served as positive controls, whereas plants not inoculated with either Streptomyces spp. or Xoo were used as negative controls. The results showed that the effect of endophytic Streptomyces spp. on BLB disease expressed as area under disease progress curve (AUDPC was not significantly different to that on control plants (P > 0.05. However, plants inoculated with endophytic Streptomyces spp. were significantly taller and produced higher tiller number than control plants (P < 0.05. Streptomyces spp. isolate AB131-1 gave the highest plant height. In vitro studies on biocontrol mechanisms of selected Streptomyces spp. isolates showed that isolate LBR02 gave the highest inhibition activity on Xoo growth, followed by AB131-1 and AB131-2. Two isolates (AB131-1 and LBR02 were able to produce chitinase, phosphatase, and siderophore which included biocontrol characteristics. Morphological and colonization studies under SEM and light microscopy confirmed that the three isolates were endophytic Streptomyces spp. from different species. These studies found that the paddy plant which was inoculated with endophytic Streptomyces spp. AB131-1 and infected by Xoo could increase the height of plant and number of tillers.

Bacterial pathogenesis of plants: future challenges from a microbial perspective: Challenges in Bacterial Molecular Plant Pathology.

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Pfeilmeier, Sebastian; Caly, Delphine L; Malone, Jacob G

2016-10-01

Plant infection is a complicated process. On encountering a plant, pathogenic microorganisms must first adapt to life on the epiphytic surface, and survive long enough to initiate an infection. Responsiveness to the environment is critical throughout infection, with intracellular and community-level signal transduction pathways integrating environmental signals and triggering appropriate responses in the bacterial population. Ultimately, phytopathogens must migrate from the epiphytic surface into the plant tissue using motility and chemotaxis pathways. This migration is coupled with overcoming the physical and chemical barriers to entry into the plant apoplast. Once inside the plant, bacteria use an array of secretion systems to release phytotoxins and protein effectors that fulfil diverse pathogenic functions (Fig. ) (Melotto and Kunkel, ; Phan Tran et al., ). As our understanding of the pathways and mechanisms underpinning plant pathogenicity increases, a number of central research challenges are emerging that will profoundly shape the direction of research in the future. We need to understand the bacterial phenotypes that promote epiphytic survival and surface adaptation in pathogenic bacteria. How do these pathways function in the context of the plant-associated microbiome, and what impact does this complex microbial community have on the onset and severity of plant infections? The huge importance of bacterial signal transduction to every stage of plant infection is becoming increasingly clear. However, there is a great deal to learn about how these signalling pathways function in phytopathogenic bacteria, and the contribution they make to various aspects of plant pathogenicity. We are increasingly able to explore the structural and functional diversity of small-molecule natural products from plant pathogens. We need to acquire a much better understanding of the production, deployment, functional redundancy and physiological roles of these molecules. Type III

Antioxidant properties of soybean seedlings inoculated with Trichoderma asperellum

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Manojlović Ana S.

2017-01-01

Full Text Available This study was conducted in order to assess the effect of inoculation of soybean (Glycine max L. seeds with Trichoderma asperellum, followed by mites (Tetranychus urticae exposure on lipid peroxidation (LP process and the activity of antioxidant enzymes. T. urticae is an occasional pest of soybean that causes biotic stress. Biotic stress leads to overproduction of reactive oxygen species (ROS which may cause damage to vital biomolecules. Enzymatic antioxidant defense systems protect plants against oxidative stress. T. asperellum is commonly used as biocontrol agent against plant pathogens. It has been suggested that previous inoculation of seeds with T. asperellum may cause induced resistance against biotic stress. The aim of this study was to determine LP intensity and antioxidant enzymes activity in inoculated and non-inoculated soybean seedlings with and without exposure to mites. Noticeably higher LP intensity was detected in non-inoculated group treated with mites compared to control group. Inoculated soybean seedlings treated with mites had lower LP intensity compared to noninoculated group. Also, it has been noticed that inoculation with Trichoderma asperellum itself, produced mild stress in plants. In addition, positive correlation between enzymes activity and LP was noticed. The level of oxidative stress in plants was followed by the change of LP intensity. According to results obtained, it was concluded that the greatest oxidative stress occurred in non-inoculated group treated with mites and that inoculation successfully reduced oxidative stress. The results indicate that inoculation of soybean seeds with T. asperellum improves resistance of soybean seedlings against mites attack. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR-31022

Plant-phytopathogen interactions: bacterial responses to environmental and plant stimuli.

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Leonard, Simon; Hommais, Florence; Nasser, William; Reverchon, Sylvie

2017-05-01

Plant pathogenic bacteria attack numerous agricultural crops, causing devastating effects on plant productivity and yield. They survive in diverse environments, both in plants, as pathogens, and also outside their hosts as saprophytes. Hence, they are confronted with numerous changing environmental parameters. During infection, plant pathogens have to deal with stressful conditions, such as acidic, oxidative and osmotic stresses; anaerobiosis; plant defenses; and contact with antimicrobial compounds. These adverse conditions can reduce bacterial survival and compromise disease initiation and propagation. Successful bacterial plant pathogens must detect potential hosts and also coordinate their possibly conflicting programs for survival and virulence. Consequently, these bacteria have a strong and finely tuned capacity for sensing and responding to environmental and plant stimuli. This review summarizes our current knowledge of the signals and genetic circuits that affect survival and virulence factor expression in three important and well-studied plant pathogenic bacteria with wide host ranges and the capacity for long-term environmental survival. These are: Ralstonia solanacerarum, a vascular pathogen that causes wilt disease; Agrobacterium tumefaciens, a biotrophic tumorigenic pathogen responsible for crown gall disease and Dickeya, a brute force apoplastic pathogen responsible for soft-rot disease. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

[Effect of mixed edaphic bacterial inoculants in the early development of improved cocoa cultivars (Theobroma cacao L.) in a traditional agroforestry system of Oaxaca, Mexico].

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Hipólito-Romero, E; Carcaño-Montiel, M G; Ramos-Prado, J M; Vázquez-Cabañas, E A; López-Reyes, L; Ricaño-Rodríguez, J

Cocoa plant (Theobroma cacao L.) is native from South America and it represents one of the most significant "bio-cultural" resources of Mesoamerica, since it is a region where it was domesticated and had a relevance as ritual drink and as currency in many pre-hispanic cultures until the arrival of the Spaniards who spread its use worldwide, and became it one of the most consumed commodity goods. Through this research, an alternative is proposed to address the problem of cultivars through the introduction of a wide variety of cocoa plants in traditional agroforestry systems, in synergy with the inoculation of nitrogen-fixing and insoluble phosphor solubilizing edaphic bacterial consortia. Four cultivars of improved grafted cocoa plants were introduced in a traditional agroforestry plot and three fertilization treatments were applied: application of biofertilizer, application of chemical fertilizer and control. Measurements of height, stem diameter, number of leaves and branches were recorded at 2 and 12 months after planting and rhizosphere microbial populations were characterized. Growth results showed good potential for all studied cultivars and it was observed that biofertilization foresees significant effects in some of the growth indicators of cocoa plant. Thereby, plant associations in an agroforestry system could be favorable to promote fruit development and resistance to pests and diseases. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Phenotypical and molecular responses of Arabidopsis thaliana roots as a result of inoculation with the auxin-producing bacterium Azospirillum brasilense.

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Spaepen, Stijn; Bossuyt, Stijn; Engelen, Kristof; Marchal, Kathleen; Vanderleyden, Jos

2014-02-01

The auxin-producing bacterium Azospirillum brasilense Sp245 can promote the growth of several plant species. The model plant Arabidopsis thaliana was chosen as host plant to gain an insight into the molecular mechanisms that govern this interaction. The determination of differential gene expression in Arabidopsis roots after inoculation with either A. brasilense wild-type or an auxin biosynthesis mutant was achieved by microarray analysis. Arabidopsis thaliana inoculation with A. brasilense wild-type increases the number of lateral roots and root hairs, and elevates the internal auxin concentration in the plant. The A. thaliana root transcriptome undergoes extensive changes on A. brasilense inoculation, and the effects are more pronounced at later time points. The wild-type bacterial strain induces changes in hormone- and defense-related genes, as well as in plant cell wall-related genes. The A. brasilense mutant, however, does not elicit these transcriptional changes to the same extent. There are qualitative and quantitative differences between A. thaliana responses to the wild-type A. brasilense strain and the auxin biosynthesis mutant strain, based on both phenotypic and transcriptomic data. This illustrates the major role played by auxin in the Azospirillum-Arabidopsis interaction, and possibly also in other bacterium-plant interactions. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Influences of Plant Species, Season and Location on Leaf Endophytic Bacterial Communities of Non-Cultivated Plants.

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Ding, Tao; Melcher, Ulrich

2016-01-01

Bacteria are known to be associated endophytically with plants. Research on endophytic bacteria has identified their importance in food safety, agricultural production and phytoremediation. However, the diversity of endophytic bacterial communities and the forces that shape their compositions in non-cultivated plants are largely uncharacterized. In this study, we explored the diversity, community structure, and dynamics of endophytic bacteria in different plant species in the Tallgrass Prairie Preserve of northern Oklahoma, USA. High throughput sequencing of amplified segments of bacterial rDNA from 81 samples collected at four sampling times from five plant species at four locations identified 335 distinct OTUs at 97% sequence similarity, representing 16 phyla. Proteobacteria was the dominant phylum in the communities, followed by the phyla Bacteriodetes and Actinobacteria. Bacteria from four classes of Proteobacteria were detected with Alphaproteobacteria as the dominant class. Analysis of molecular variance revealed that host plant species and collecting date had significant influences on the compositions of the leaf endophytic bacterial communities. The proportion of Alphaproteobacteria was much higher in the communities from Asclepias viridis than from other plant species and differed from month to month. The most dominant bacterial groups identified in LDA Effect Size analysis showed host-specific patterns, indicating mutual selection between host plants and endophytic bacteria and that leaf endophytic bacterial compositions were dynamic, varying with the host plant's growing season in three distinct patterns. In summary, next generation sequencing has revealed variations in the taxonomic compositions of leaf endophytic bacterial communities dependent primarily on the nature of the plant host species.

Influences of Plant Species, Season and Location on Leaf Endophytic Bacterial Communities of Non-Cultivated Plants.

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Tao Ding

Full Text Available Bacteria are known to be associated endophytically with plants. Research on endophytic bacteria has identified their importance in food safety, agricultural production and phytoremediation. However, the diversity of endophytic bacterial communities and the forces that shape their compositions in non-cultivated plants are largely uncharacterized. In this study, we explored the diversity, community structure, and dynamics of endophytic bacteria in different plant species in the Tallgrass Prairie Preserve of northern Oklahoma, USA. High throughput sequencing of amplified segments of bacterial rDNA from 81 samples collected at four sampling times from five plant species at four locations identified 335 distinct OTUs at 97% sequence similarity, representing 16 phyla. Proteobacteria was the dominant phylum in the communities, followed by the phyla Bacteriodetes and Actinobacteria. Bacteria from four classes of Proteobacteria were detected with Alphaproteobacteria as the dominant class. Analysis of molecular variance revealed that host plant species and collecting date had significant influences on the compositions of the leaf endophytic bacterial communities. The proportion of Alphaproteobacteria was much higher in the communities from Asclepias viridis than from other plant species and differed from month to month. The most dominant bacterial groups identified in LDA Effect Size analysis showed host-specific patterns, indicating mutual selection between host plants and endophytic bacteria and that leaf endophytic bacterial compositions were dynamic, varying with the host plant's growing season in three distinct patterns. In summary, next generation sequencing has revealed variations in the taxonomic compositions of leaf endophytic bacterial communities dependent primarily on the nature of the plant host species.

Phyllosphere Microbiota Composition and Microbial Community Transplantation on Lettuce Plants Grown Indoors

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Williams, Thomas R.

2014-01-01

ABSTRACT The aerial surfaces of plants, or phyllosphere, are microbial habitats important to plant and human health. In order to accurately investigate microbial interactions in the phyllosphere under laboratory conditions, the composition of the phyllosphere microbiota should be representative of the diversity of microorganisms residing on plants in nature. We found that Romaine lettuce grown in the laboratory contained 10- to 100-fold lower numbers of bacteria than age-matched, field-grown lettuce. The bacterial diversity on laboratory-grown plants was also significantly lower and contained relatively higher proportions of Betaproteobacteria as opposed to the Gammaproteobacteria-enriched communities on field lettuce. Incubation of field-grown Romaine lettuce plants in environmental growth chambers for 2 weeks resulted in bacterial cell densities and taxa similar to those on plants in the field but with less diverse bacterial populations overall. In comparison, the inoculation of laboratory-grown Romaine lettuce plants with either freshly collected or cryopreserved microorganisms recovered from field lettuce resulted in the development of a field-like microbiota on the lettuce within 2 days of application. The survival of an inoculated strain of Escherichia coli O157:H7 was unchanged by microbial community transfer; however, the inoculation of E. coli O157:H7 onto those plants resulted in significant shifts in the abundance of certain taxa. This finding was strictly dependent on the presence of a field-associated as opposed to a laboratory-associated microbiota on the plants. Phyllosphere microbiota transplantation in the laboratory will be useful for elucidating microbial interactions on plants that are important to agriculture and microbial food safety. PMID:25118240

Inoculum pretreatment affects bacterial survival, activity and catabolic gene expression during phytoremediation of diesel contaminated soil.

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Khan, Sumia; Afzal, Muhammad; Iqbal, Samina; Mirza, Muhammad Sajjad; Khan, Qaiser M

2013-04-01

Plant-bacteria partnership is a promising approach for remediating soil contaminated with organic pollutants. The colonization and metabolic activity of an inoculated microorganism depend not only on environmental conditions but also on the physiological condition of the applied microorganisms. This study assessed the influence of different inoculum pretreatments on survival, gene abundance and catabolic gene expression of an applied strain (Pantoea sp. strain BTRH79) in the rhizosphere of ryegrass vegetated in diesel contaminated soil. Maximum bacterium survival, gene abundance and expression were observed in the soil inoculated with bacterial cells that had been pregrown on complex medium, and hydrocarbon degradation and genotoxicity reduction were also high in this soil. These findings propose that use of complex media for growing plant inocula may enhance bacterial survival and colonization and subsequently the efficiency of pollutant degradation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bacterial Gibberellins Induce Systemic Resistance of Plants

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I. N. FEKLISTOVA

2014-06-01

Full Text Available It is generally agreed today that some rhizosphere bacteria can ensure induced systemic resistance to pathogens. In this paper we tested the ability of gibberellins produced by rhizosphere non-pathogenic bacteria Pseudomonas aurantiaca to induce systemic resistance to alternariosis agent – Alternaria brassicicola – in oilseed rape plants.Oilseed rape (Brássica nápus is one of the most promising oil-bearing croppers. It allows improving the supply of population with vegetable oil, animal and poultry industries with high quality vegetable protein. It is used for biofuel production as well.Gibberellin preparation was isolated from liquid culture of strain Pseudomonas aurantiaca grown in 250 mL of M9 medium (48 h, 28 °C under darkroom conditions. Gibberellins were extracted according procedure described by Tien et al. (1979. Gibberellins concentration in the medium was determined by fluorometric method.Elicitor activity of bacterial metabolites – gibberellins – was analyzed in model system of artificial inoculation of oilseed rape germs with phytopathogenic fungi Alternaria brassicicola. The elicitor action efficiency was evaluated on the 15th day of oilseed rape cultivation based on the percentage of leaf surface covered by necrotic lesions.Gibberellins were shown to induce systemic resistance resulted in decreasing of oil seed plants   vulnerability by 52.7%.It is known that under the unfavorable conditions plants synthesis the reactive oxygen intermediates   which activate destructive processes. One of the first organism reactions to stress action is the change of the lipid peroxidation level. It was shown that treatment of the soil with gibberellins resulted in decreasing of the lipid peroxidation level twofold.Gibberellins were shown to have a similar effect on permeability of cell membranes for free nucleotides. The permeability of cell membranes in leaves decreased 2.8-fold at room temperature. We suggest that gibberellins

Increased root exudation of /sup 14/C-compounds by sorghum seedlings inoculated with nitrogen-fixing bacteria

Energy Technology Data Exchange (ETDEWEB)

Lee, K.J. (Institute of Forest Genetics, Suweon (Republic of Korea)); Gaskins, M.H. (Florida Univ., Gainesville (USA). Dept. of Agriculture)

1982-01-01

Organic components leaked from Sorghum bicolor seedlings ('root exudates') were examined by recovering /sup 14/C labelled compounds from root solutions of seedlings inoculated with Azospirillum brasilense, Azotobacter vinelandii or Klebsiella pneumoniae nif-. Up to 3.5% of the total /sup 14/C recovered from shoots, roots, and nutrient solutions was found in the root solutions. Inoculation with Azospirillum and Azotobacter increased the amounts of /sup 14/C and decreased the amounts of carbohydrates in the root solutions. When sucrose was added as a carbon source for the bacteria, the increase of /sup 14/C in the solutions did not occur. Quantities of /sup 14/C found in the root solutions were proportional to amounts of mineral nitrogen supplied to the plants. Bacterial growth also was proportional to nitrogen levels. When sorghum plants were grown in soil and labelled with /sup 14/CO/sub 2/, about 15% of the total /sup 14/C recovered within 48 hours exposure was found in soil leachates.

Effect of plant growth-promoting bacteria on the growth and fructan production of Agave americana L.

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Neyser De La Torre-Ruiz

Full Text Available ABSTRACT The effect of plant growth-promoting bacteria inoculation on plant growth and the sugar content in Agave americana was assessed. The bacterial strains ACO-34A, ACO-40, and ACO-140, isolated from the A. americana rhizosphere, were selected for this study to evaluate their phenotypic and genotypic characteristics. The three bacterial strains were evaluated via plant inoculation assays, and Azospirillum brasilense Cd served as a control strain. Phylogenetic analysis based on the 16S rRNA gene showed that strains ACO-34A, ACO-40 and ACO-140 were Rhizobium daejeonense, Acinetobacter calcoaceticus and Pseudomonas mosselii, respectively. All of the strains were able to synthesize indole-3-acetic acid (IAA, solubilize phosphate, and had nitrogenase activity. Inoculation using the plant growth-promoting bacteria strains had a significant effect (p < 0.05 on plant growth and the sugar content of A. americana, showing that these native plant growth-promoting bacteria are a practical, simple, and efficient alternative to promote the growth of agave plants with proper biological characteristics for agroindustrial and biotechnological use and to increase the sugar content in this agave species.

Rhizospheric Bacterial Strain Brevibacterium casei MH8a Colonizes Plant Tissues and Enhances Cd, Zn, Cu Phytoextraction by White Mustard.

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Płociniczak, Tomasz; Sinkkonen, Aki; Romantschuk, Martin; Sułowicz, Sławomir; Piotrowska-Seget, Zofia

2016-01-01

Environmental pollution by heavy metals has become a serious problem in the world. Phytoextraction, which is one of the plant-based technologies, has attracted the most attention for the bioremediation of soils polluted with these contaminants. The aim of this study was to determine whether the multiple-tolerant bacterium, Brevibacterium casei MH8a isolated from the heavy metal-contaminated rhizosphere soil of Sinapis alba L., is able to promote plant growth and enhance Cd, Zn, and Cu uptake by white mustard under laboratory conditions. Additionally, the ability of the rifampicin-resistant spontaneous mutant of MH8a to colonize plant tissues and its mechanisms of plant growth promotion were also examined. In order to assess the ecological consequences of bioaugmentation on autochthonous bacteria, the phospholipid fatty acid (PLFA) analysis was used. The MH8a strain exhibited the ability to produce ammonia, 1-amino-cyclopropane-1-carboxylic acid deaminase, indole 3-acetic acid and HCN but was not able to solubilize inorganic phosphate and produce siderophores. Introduction of MH8a into soil significantly increased S. alba biomass and the accumulation of Cd (208%), Zn (86%), and Cu (39%) in plant shoots in comparison with those grown in non-inoculated soil. Introduced into the soil, MH8a was able to enter the plant and was found in the roots and leaves of inoculated plants thus indicating its endophytic features. PLFA analysis revealed that the MH8a that was introduced into soil had a temporary influence on the structure of the autochthonous bacterial communities. The plant growth-promoting features of the MH8a strain and its ability to enhance the metal uptake by white mustard and its long-term survival in soil as well as its temporary impact on autochthonous microorganisms make the strain a suitable candidate for the promotion of plant growth and the efficiency of phytoextraction.

Root inoculation with Pseudomonas putida KT2440 induces transcriptional and metabolic changes and systemic resistance in maize plants

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Chantal ePlanchamp

2015-01-01

Full Text Available Pseudomonas putida KT2440 (KT2440 rhizobacteria colonize a wide range of plants. They have been extensively studied for their capacity to adhere to maize seeds, to tolerate toxic secondary metabolites produced by maize roots and to be attracted by maize roots. However, the response of maize plants to KT2440 colonization has not been investigated yet. Maize roots were inoculated with KT2440 and the local (roots and systemic (leaves early plant responses were investigated. The colonization behavior of KT2440 following application to maize seedlings was investigated and transcriptional analysis of stress- and defense-related genes as well as metabolite profiling of local and systemic maize tissues of KT2440-inoculated were performed. The local and systemic responses differed and more pronounced changes were observed in roots compared to leaves. Early in the interaction roots responded via jasmonic acid- and abscisic acid-dependent signaling. Interestingly, during later steps, the salicylic acid pathway was suppressed. Metabolite profiling revealed the importance of plant phospholipids in KT2440-maize interactions. An additional important maize secondary metabolite, a form of benzoxazinone, was also found to be differently abundant in roots three days after KT2440 inoculation. However, the transcriptional and metabolic changes observed in bacterized plants early during the interaction were minor and became even less pronounced with time, indicating an accommodation state of the plant to the presence of KT2440. Since the maize plants reacted to the presence of KT2440 in the rhizosphere, we also investigated the ability of these bacteria to trigger induced systemic resistance (ISR against the maize anthracnose fungus Colletotrichum graminicola. The observed resistance was expressed as strongly reduced leaf necrosis and fungal development in infected bacterized plants compared to non-bacterized controls, showing the potential of KT2440 to act as

Sunflower growth according to seed inoculation with endophytic bacteria

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Juliana Fernandes dos Santos

2014-06-01

Full Text Available The sunflower crop has a great importance worldwide, due to the oil of excellent quality extracted from its seeds and in natura grains that are consumed in various ways. However, drought is one of the main environmental factors that limit its yield. An experiment was carried out under controlled greenhouse conditions, in a completely randomized experimental design, in order to determine the effect of endophytic bacteria inoculation (Bacillus sp. and Enterobacter cloacae on the growth and contents of nutrients and organic solutes, in sunflower leaves and roots under water deficit. Plant height, stem diameter, fresh and dry biomass of shoot and roots, as well as contents of N, P, K, soluble carbohydrates, free proline, free amino acids and soluble proteins, were determined at 35 days after the plant emergence. The water deficit reduced plant growth regardless inoculation. However, under optimum conditions of soil moisture, the combination of both endophytic bacteria increased the sunflower growth. The water deficit also increased the N and K contents in leaves, as well as the organic solutes content in shoots, especially in inoculated plants. These results suggest that the inoculation of endophytic bacteria may increase the capacity of drought stressed plants to perform the osmotic adjustment through a higher accumulation of organic solutes, when compared to plants not inoculated.

Selenium bioavailability and uptake as affected by four different plants in a loamy clay soil with particular attention to mycorrhizae inoculated ryegrass

International Nuclear Information System (INIS)

Munier-Lamy, C.; Deneux-Mustin, S.; Mustin, C.; Merlet, D.; Berthelin, J.; Leyval, C.

2007-01-01

The aim of this study was to investigate the influence of plant species, especially of their rhizosphere soil, and of inoculation with an arbuscular mycorrhizal (AM) fungus on the bioavailability of selenium and its transfer in soil-plant systems. A pot experiment was performed with a loamy clay soil and four plant species: maize, lettuce, radish and ryegrass, the last one being inoculated or not with an arbuscular mycorrhizal fungus (Glomus mosseae). Plant biomass and Se concentration in shoots and roots were estimated at harvest. Se bioavailability in rhizosphere and unplanted soil was evaluated using sequential extractions. Plant biomass and selenium uptake varied with plant species. The quantity of rhizosphere soil also differed between plants and was not proportional to plant biomass. The highest plant biomass, Se concentration in plants, and soil to plant transfer factor were obtained with radish. The lowest Se transfer factors were obtained with ryegrass. For the latter, mycorrhizal inoculation did not significantly affect plant growth, but reduced selenium transfer from soil to plant by 30%. In unplanted soil after 65 days aging, more than 90% of added Se was water-extractable. On the contrary, Se concentration in water extracts of rhizosphere soil represented less than 1% and 20% of added Se for ryegrass and maize, respectively. No correlation was found between the water-extractable fraction and Se concentration in plants. The speciation of selenium in the water extracts indicated that selenate was reduced, may be under organic forms, in the rhizosphere soil

Azospirillum Inoculation Alters Nitrate Reductase Activity and Nitrogen Uptake in Wheat Plant Under Water Deficit Conditions

OpenAIRE

N. Aliasgharzad, N. Aliasgharzad; Heydaryan, Zahra; Sarikhani, M.R

2014-01-01

Water deficit stress usually diminishes nitrogen uptake by plants. There are evidences that some nitrogen fixing bacteria can alleviate this stress by supplying nitrogen and improving its metabolism in plants. Four Azospirillum strains, A. lipoferum AC45-II, A. brasilense AC46-I, A. irakense AC49-VII and A. irakense AC51-VI were tested for nitrate reductase activity (NRA). In a pot culture experiment using a sandy loam soil, wheat plants (Triticum aestivum L. cv. Sardari) were inoculated with...

Relationships between phyllosphere bacterial communities and plant functional traits in a neotropical forest

Science.gov (United States)

Kembel, Steven W.; O’Connor, Timothy K.; Arnold, Holly K.; Hubbell, Stephen P.; Wright, S. Joseph; Green, Jessica L.

2014-01-01

The phyllosphere—the aerial surfaces of plants, including leaves—is a ubiquitous global habitat that harbors diverse bacterial communities. Phyllosphere bacterial communities have the potential to influence plant biogeography and ecosystem function through their influence on the fitness and function of their hosts, but the host attributes that drive community assembly in the phyllosphere are poorly understood. In this study we used high-throughput sequencing to quantify bacterial community structure on the leaves of 57 tree species in a neotropical forest in Panama. We tested for relationships between bacterial communities on tree leaves and the functional traits, taxonomy, and phylogeny of their plant hosts. Bacterial communities on tropical tree leaves were diverse; leaves from individual trees were host to more than 400 bacterial taxa. Bacterial communities in the phyllosphere were dominated by a core microbiome of taxa including Actinobacteria, Alpha-, Beta-, and Gammaproteobacteria, and Sphingobacteria. Host attributes including plant taxonomic identity, phylogeny, growth and mortality rates, wood density, leaf mass per area, and leaf nitrogen and phosphorous concentrations were correlated with bacterial community structure on leaves. The relative abundances of several bacterial taxa were correlated with suites of host plant traits related to major axes of plant trait variation, including the leaf economics spectrum and the wood density–growth/mortality tradeoff. These correlations between phyllosphere bacterial diversity and host growth, mortality, and function suggest that incorporating information on plant–microbe associations will improve our ability to understand plant functional biogeography and the drivers of variation in plant and ecosystem function. PMID:25225376

THE EFFECTS OF INOCULANT LACTIC ACID BACTERIA ON THE FERMENTATION AND AEROBIC STABILITY OF SUNFLOWER SILAGE

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Fisun Koc

2009-12-01

Full Text Available This study was carried out to determine the effects of actic acid bacterial inoculant on the fermentation and aerobic stability of sunflower silages. Sunflower was harvested at the milk stage. Inoculant-1174 (Pioneer®,USA was used as homofermentative lactic acid bacterial inoculant. Inoculant was applied 6.00 log10 cfu/g silage levels. Silages with no additive served as controls. After treatment, the chopped sunflower was ensiled in the PVC type laboratory silos. Three silos for each group were sampled for chemical and microbiological analysis on days 2, 4, 7, 14, 21, 28 and 56 after ensiling. At the end of the ensiling period, all silages were subjected to an aerobic stability test for 14 days. Neither inoculant improved the fermentation parameters of sunflower silages. At the end of the ensiling period, inoculant increased lactic acid bacteria (LAB and decreased yeast and mould numbers of silages. Inoculant treatment did not affect aerobic stability of silages.

Photosynthetic and Ultrastructure Parameters of Maize Plants are Affected During the Phyto-Rhizoremediation Process of Degraded Metal Working Fluids.

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Grijalbo, Lucía; Gutierrez Mañero, Francisco Javier; Fernandez-Pascual, Mercedes; Lucas, Jose Antonio

2015-01-01

A phyto-rhizoremediation system using corn and esparto fiber as rooting support to remediate degraded metal working fluids (dMWFs) has been developed in the present study. In order to improve the process, plants were inoculated at the root level with bacteria either individually, and with a consortium of strains. All strains used were able to grow with MWFs. The results show that this system significantly lowers the Chemical Oxygen Demand below legal limits within 5 days. However, results were only improved with the bacterial consortium. Despite the effectiveness of the phyto-rhizoremediation process, plants are damaged at the photosynthetic level according to the photosynthetic parameters measured, as well as at the ultrastructure of the vascular cylinder and the Bundle Sheath Cells. Interestingly, the bacterial inoculation protects against this damage. Therefore, it seems that that the inoculation with bacteria can protect the plants against these harmful effects.

An optimized regulating method for composting phosphorus fractions transformation based on biochar addition and phosphate-solubilizing bacteria inoculation.

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Wei, Yuquan; Zhao, Yue; Wang, Huan; Lu, Qian; Cao, Zhenyu; Cui, Hongyang; Zhu, Longji; Wei, Zimin

2016-12-01

The study was conducted to investigate the influence of biochar and/or phosphate-solubilizing bacteria (PSB) inoculants on microbial biomass, bacterial community composition and phosphorus (P) fractions during kitchen waste composting amended with rock phosphate (RP). There were distinct differences in the physic-chemical parameters, the proportion of P fractions and bacterial diversity in different treatments. The contribution of available P fractions increased during composting especially in the treatment with the addition of PSB and biochar. Redundancy analysis showed that bacterial compositions were significantly influenced by P content, inoculation and biochar. Variance partitioning further showed that synergy of inoculated PSB and indigenous bacterial communities and the joint effect between biochar and bacteria explained the largest two proportion of the variation in P fractions. Therefore, the combined application of PSB and biochar to improve the inoculation effect and an optimized regulating method were suggested based on the distribution of P fractions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Impact of phosphate-solubilizing bacteria inoculation methods on phosphorus transformation and long-term utilization in composting.

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Wei, Yuquan; Zhao, Yue; Fan, Yuying; Lu, Qian; Li, Mingxiao; Wei, Qingbin; Zhao, Yi; Cao, Zhenyu; Wei, Zimin

2017-10-01

This study aimed to assess the effect of phosphate-solubilizing bacteria (PSB) application and inoculation methods on rock phosphate (RP) solubilization and bacterial community during composting. The results showed that PSB inoculation in different stages of composting, especially both in the beginning and cooling stages, not only improved the diversity and abundance of PSB and bacterial community, but also distinctly increased the content of potential available phosphorus. Redundancy analysis indicated that the combined inoculation of PSB in the initial stage with higher inoculation amount and in the cooling stage with lower inoculation amount was the best way to improve the inoculation effect and increase the solubilization and utilization of RP during composting. Besides, we suggested three methods to improve phosphorus transformation and long-term utilization efficiency in composts based on biological fixation of phosphates by humic substance and phosphate-accumulating organisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impact of Cropping Systems, Soil Inoculum, and Plant Species Identity on Soil Bacterial Community Structure.

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Ishaq, Suzanne L; Johnson, Stephen P; Miller, Zach J; Lehnhoff, Erik A; Olivo, Sarah; Yeoman, Carl J; Menalled, Fabian D

2017-02-01

Farming practices affect the soil microbial community, which in turn impacts crop growth and crop-weed interactions. This study assessed the modification of soil bacterial community structure by organic or conventional cropping systems, weed species identity [Amaranthus retroflexus L. (redroot pigweed) or Avena fatua L. (wild oat)], and living or sterilized inoculum. Soil from eight paired USDA-certified organic and conventional farms in north-central Montana was used as living or autoclave-sterilized inoculant into steam-pasteurized potting soil, planted with Am. retroflexus or Av. fatua and grown for two consecutive 8-week periods to condition soil nutrients and biota. Subsequently, the V3-V4 regions of the microbial 16S rRNA gene were sequenced by Illumina MiSeq. Treatments clustered significantly, with living or sterilized inoculum being the strongest delineating factor, followed by organic or conventional cropping system, then individual farm. Living inoculum-treated soil had greater species richness and was more diverse than sterile inoculum-treated soil (observed OTUs, Chao, inverse Simpson, Shannon, P soil contained more Chloroflexi and Acidobacteria, while the sterile inoculum soil had more Bacteroidetes, Firmicutes, Gemmatimonadetes, and Verrucomicrobia. Organically farmed inoculum-treated soil had greater species richness, more diversity (observed OTUs, Chao, Shannon, P soil. Cyanobacteria were higher in pots growing Am. retroflexus, regardless of inoculum type, for three of the four organic farms. Results highlight the potential of cropping systems and species identity to modify soil bacterial communities, subsequently modifying plant growth and crop-weed competition.

Specific amplification of bacterial DNA by optimized so-called universal bacterial primers in samples rich of plant DNA.

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Dorn-In, Samart; Bassitta, Rupert; Schwaiger, Karin; Bauer, Johann; Hölzel, Christina S

2015-06-01

Universal primers targeting the bacterial 16S-rRNA-gene allow quantification of the total bacterial load in variable sample types by qPCR. However, many universal primer pairs also amplify DNA of plants or even of archaea and other eukaryotic cells. By using these primers, the total bacterial load might be misevaluated, whenever samples contain high amounts of non-target DNA. Thus, this study aimed to provide primer pairs which are suitable for quantification and identification of bacterial DNA in samples such as feed, spices and sample material from digesters. For 42 primers, mismatches to the sequence of chloroplasts and mitochondria of plants were evaluated. Six primer pairs were further analyzed with regard to the question whether they anneal to DNA of archaea, animal tissue and fungi. Subsequently they were tested with sample matrix such as plants, feed, feces, soil and environmental samples. To this purpose, the target DNA in the samples was quantified by qPCR. The PCR products of plant and feed samples were further processed for the Single Strand Conformation Polymorphism method followed by sequence analysis. The sequencing results revealed that primer pair 335F/769R amplified only bacterial DNA in samples such as plants and animal feed, in which the DNA of plants prevailed. Copyright © 2015 Elsevier B.V. All rights reserved.

Changes in Composition of Caecal Microbiota Associated with Increased Colon Inflammation in Interleukin-10 Gene-Deficient Mice Inoculated with Enterococcus Species

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Shalome A. Bassett

2015-03-01

Full Text Available Human inflammatory bowel disease (IBD is a chronic intestinal disease where the resident microbiota contributes to disease development, yet the specific mechanisms remain unclear. Interleukin-10 gene-deficient (Il10-/- mice develop inflammation similar to IBD, due in part to an inappropriate response to commensal bacteria. We have previously reported changes in intestinal morphology and colonic gene expression in Il10-/- mice in response to oral bacterial inoculation. In this study, we aimed to identify specific changes in the caecal microbiota associated with colonic inflammation in these mice. The microbiota was evaluated using pyrotag sequencing, denaturing gradient gel electrophoresis (DGGE and quantitative real-time PCR. Microbiota profiles were influenced by genotype of the mice and by bacterial inoculation, and a strong correlation was observed between the microbiota and colonic inflammation scores. Although un-inoculated Il10-/- and C57 mice had similar microbiota communities, bacterial inoculation resulted in different changes to the microbiota in Il10-/- and C57 mice. Inoculated Il10-/- mice had significantly less total bacteria than un-inoculated Il10-/- mice, with a strong negative correlation between total bacterial numbers, relative abundance of Escherichia/Shigella, microbiota diversity, and colonic inflammation score. Our results show a putative causative role for the microbiota in the development of IBD, with potentially key roles for Akkermansia, or for Bacteroides, Helicobacter, Parabacteroides, and Alistipes, depending on the composition of the bacterial inoculum. These data support the use of bacterially-inoculated Il10-/- mice as an appropriate model to investigate human IBD.

Effect of free and symbiotic nitrogen fixing bacterial co-inoculation on seed and seedling of soybean seeds produced under deficit water condition

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Hamed Hadi

2016-04-01

Full Text Available Effect of free and symbiotic nitrogen fixing bacteria on seed and seedling produced seeds under deficit irrigation was conducted in laboratory and field experiments in 2006. In laboratory of karaj’s Seed and Plant Research and Certificate Institute an experiment was conducted based on factorial in form of completely randomized design with four replications and in field’s of Islamic Azad University, Varamin Branch were split factorial in form of randomized completely block design with three replications. Treatments included water stress [Irrigation after 50 (Normal irrigation, 100 (Middle stress, 150 (Severe stress mm evaporation from pan class A], Cultivar [Manokin & Williams and SRF×T3 Line] and inoculation [Inoculation with Bradyrhizobium japonicum, Bradyrhizobium japonicum co-inoculated with Azotobacter chroococcum, No seed inoculation]. Results showed that drought stress decreased the uniformity and germination speed and seedling emergence. Bacteria increased leaf dry weight, stem dry weight, leaf area and seedling vigor index but had no effect on emergence. In irrigation levels inoculated treatments had higher seedling length, leaf, stem, seedling dry weight and seedling vigor. Severs stress seeds inoculated with Bradyrhizobium japonicum had higher root dry weight than control. Therefore in seeds which were produced under deficit irrigation conditions, bacteria increased seedlings vigor.

Influence of the season in the development of symptoms in plants of ‘Grande naine’ artificially inoculated with Mycosphaerella fijiensis in greenhouse

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Michel Leiva-Mora

2011-01-01

Full Text Available Plant pathogen fungi required favorable conditions to invade and colonize plant tissues, which may change according to the season of the year. This work is aimed to evaluate the influence of different seasons (June-August and August-October in the development of symptoms in ‘Grande naine’ artificially inoculated with Mycosphaerella fijiensis in greenhouse. Inoculation assays were done during three consecutive years (2005, 2006 and 2007. None differences in attack intensity between different seasons were observed, at 14, 21, 35, 49 y 63 days post inoculation (dpi. This shows that the development of symptoms in greenhouse was similar in the period from June to October. Temperature and humidity have not been controlled by all laboratories that conduct studies related to M. fijiensis. Then, to choose the appropriate season for artificial inoculations is a prerequisite for effective development of M. fijiensis infective cycle and to avoid masking in the phenotype of resistance. Key words: attack intensity, Black Sigatoka, mycelia

Health monitoring of plants by their emitted volatiles: A temporary increase in the concentration of nethyl salicylate after pathogen inoculation of tomato plants at greenhouse scale

NARCIS (Netherlands)

Jansen, R.M.C.; Hofstee, J.W.; Verstappen, F.W.A.; Bouwmeester, H.J.; Posthumus, M.A.; Henten, van E.J.

2011-01-01

This paper describes a method to alert growers of the presence of a pathogen infection in their greenhouse based on the detection of pathogen-induced emissions of volatile organic compounds (VOCs) from plants. Greenhouse-grown plants were inoculated with spores of a fungus to learn more about this

Plant-associated bacterial populations on native and invasive plant species: comparisons between 2 freshwater environments.

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Olapade, Ola A; Pung, Kayleigh

2012-06-01

Plant-microbial interactions have been well studied because of the ecological importance of such relationships in aquatic systems. However, general knowledge regarding the composition of these biofilm communities is still evolving, partly as a result of several confounding factors that are attributable to plant host properties and to hydrodynamic conditions in aquatic environments. In this study, the occurrences of various bacterial phylogenetic taxa on 2 native plants, i.e., mayapple (Podophyllum peltatum L.) and cow parsnip (Heracleum maximum Bartram), and on an invasive species, i.e., garlic mustard (Alliaria petiolata (M. Bieb.) Cavara & Grande), were quantitatively examined using nucleic acid staining and fluorescence in situ hybridization. The plants were incubated in triplicates for about a week within the Kalamazoo River and Pierce Cedar Creek as well as in microcosms. The bacterial groups targeted for enumeration are known to globally occur in relatively high abundance and are also ubiquitously distributed in freshwater environments. Fluorescence in situ hybridization analyses of the bacterioplankton assemblages revealed that the majority of bacterial cells that hybridized with the different probes were similar between the 2 sites. In contrast, the plant-associated populations while similar on the 3 plants incubated in Kalamazoo River, their representations were highest on the 2 native plants relative to the invasive species in Pierce Cedar Creek. Overall, our results further suggested that epiphytic bacterial assemblages are probably under the influences of and probably subsequently respond to multiple variables and conditions in aquatic milieus.

Effects of the inoculations using bacteria producing ACC deaminase on ethylene metabolism and growth of wheat grown under different soil water contents.

Science.gov (United States)

Zhang, Guozhuang; Sun, Yonglin; Sheng, Hao; Li, Haichao; Liu, Xiping

2018-04-01

Crop growth and productivity are often impacted by the increased ethylene content induced by adverse environmental conditions such drought. Inoculations with bacteria producing ACC deaminase is considered as a potential biological approach to improve the growth and tolerance of stressed plants by lowering endogenous ethylene level. In this study, germinated wheat seeds were inoculated using three species of the rhizobacteria, which were isolated from the rhizosphere of wheat growing in dryland, and sown in pots. After three weeks, wheat seedlings were exposed to non-limiting water condition, medium drought and severe drought, respectively, for six weeks. The results showed that, irrespective of rhizobacterial inoculations, decreased soil water contents stimulated wheat ethylene metabolism, which was reflected by the significantly increased activity of ACC synthetase and ACC oxidase, besides an increased content of ACC both in the roots and leaves, and an enhanced capacity of leaves to release ethylene, concomitant with a significant decline in shoot and roots biomass. The inoculations of all three rhizobacterial species under each water condition reduced ACC content in wheat leaves, but effects of the inoculations on ACC synthase and ACC oxidase activity in the leaves and roots, ACC content in the roots, the capacity of leaves to release ethylene, and wheat growth varied with water conditions and bacterial species. Hence, both soil water conditions and rhizobacterial inoculations acted on all the processes of ethylene metabolism, with the former being dominant. The inoculations under non-limiting water condition and medium drought promoted shoot and root growth of wheat plants. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Plants of the fynbos biome harbour host species-specific bacterial communities.

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Miyambo, Tsakani; Makhalanyane, Thulani P; Cowan, Don A; Valverde, Angel

2016-08-01

The fynbos biome in South Africa is globally recognised as a plant biodiversity hotspot. However, very little is known about the bacterial communities associated with fynbos plants, despite interactions between primary producers and bacteria having an impact on the physiology of both partners and shaping ecosystem diversity. This study reports on the structure, phylogenetic composition and potential roles of the endophytic bacterial communities located in the stems of three fynbos plants (Erepsia anceps, Phaenocoma prolifera and Leucadendron laureolum). Using Illumina MiSeq 16S rRNA sequencing we found that different subpopulations of Deinococcus-Thermus, Alphaproteobacteria, Acidobacteria and Firmicutes dominated the endophytic bacterial communities. Alphaproteobacteria and Actinobacteria were prevalent in P. prolifera, whereas Deinococcus-Thermus dominated in L. laureolum, revealing species-specific host-bacteria associations. Although a high degree of variability in the endophytic bacterial communities within hosts was observed, we also detected a core microbiome across the stems of the three plant species, which accounted for 72% of the sequences. Altogether, it seems that both deterministic and stochastic processes shaped microbial communities. Endophytic bacterial communities harboured putative plant growth-promoting bacteria, thus having the potential to influence host health and growth. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Exploring the plant-associated bacterial communities in Medicago sativa L

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Pini Francesco

2012-05-01

Full Text Available Abstract Background Plant-associated bacterial communities caught the attention of several investigators which study the relationships between plants and soil and the potential application of selected bacterial species in crop improvement and protection. Medicago sativa L. is a legume crop of high economic importance as forage in temperate areas and one of the most popular model plants for investigations on the symbiosis with nitrogen fixing rhizobia (mainly belonging to the alphaproteobacterial species Sinorhizobium meliloti. However, despite its importance, no studies have been carried out looking at the total bacterial community associated with the plant. In this work we explored for the first time the total bacterial community associated with M. sativa plants grown in mesocosms conditions, looking at a wide taxonomic spectrum, from the class to the single species (S. meliloti level. Results Results, obtained by using Terminal-Restriction Fragment Length Polymorphism (T-RFLP analysis, quantitative PCR and sequencing of 16 S rRNA gene libraries, showed a high taxonomic diversity as well as a dominance by members of the class Alphaproteobacteria in plant tissues. Within Alphaproteobacteria the families Sphingomonadaceae and Methylobacteriaceae were abundant inside plant tissues, while soil Alphaproteobacteria were represented by the families of Hyphomicrobiaceae, Methylocystaceae, Bradyirhizobiaceae and Caulobacteraceae. At the single species level, we were able to detect the presence of S. meliloti populations in aerial tissues, nodules and soil. An analysis of population diversity on nodules and soil showed a relatively low sharing of haplotypes (30-40% between the two environments and between replicate mesocosms, suggesting drift as main force shaping S. meliloti population at least in this system. Conclusions In this work we shed some light on the bacterial communities associated with M. sativa plants, showing that Alphaproteobacteria may

Accessing inoculation methods of maize and wheat with Azospirillum brasilense.

Science.gov (United States)

Fukami, Josiane; Nogueira, Marco Antonio; Araujo, Ricardo Silva; Hungria, Mariangela

2016-03-01

The utilization of inoculants containing Azospirillum is becoming more popular due to increasing reports of expressive gains in grain yields. However, incompatibility with pesticides used in seed treatments represents a main limitation for a successful inoculation. Therefore, in this study we searched for alternatives methods for seed inoculation of maize and wheat, aiming to avoid the direct contact of bacteria with pesticides. Different doses of inoculants containing Azospirillum brasilense were employed to perform inoculation in-furrow, via soil spray at sowing and via leaf spray after seedlings had emerged, in comparison to seed inoculation. Experiments were conducted first under greenhouse controlled conditions and then confirmed in the field at different locations in Brazil. In the greenhouse, most parameters measured responded positively to the largest inoculant dose used in foliar sprays, but benefits could also be observed from both in-furrow and soil spray inoculation. However, our results present evidence that field inoculation with plant-growth promoting bacteria must consider inoculant doses, and point to the need of fine adjustments to avoid crossing the threshold of growth stimulation and inhibition. All inoculation techniques increased the abundance of diazotrophic bacteria in plant tissues, and foliar spray improved colonization of leaves, while soil inoculations favored root and rhizosphere colonization. In field experiments, inoculation with A. brasilense allowed for a 25 % reduction in the need for N fertilizers. Our results have identified alternative methods of inoculation that were as effective as the standard seed inoculation that may represent an important strategy to avoid the incompatibility between inoculant bacteria and pesticides employed for seed treatment.

Beneficial role of hydrophytes in removing Cr(VI) from wastewater in association with chromate-reducing bacterial strains Ochrobactrum intermedium and Brevibacterium.

Science.gov (United States)

Faisal, Muhammad; Hasnain, Shahida

2005-01-01

This study deals with the use of three chromium-resistant bacterial strains (Ochrobactrum intermedium CrT-1, Brevibacterium CrT-13, and CrM-1) in conjunction with Eichornia crassipes for the removal of toxic chromium from wastewater. Bacterial strains resulted in reduced uptake of chromate into inoculated plants as compared to noninoculated control plants. In the presence of different heavy metals, chromium uptake into the plants was 28.7 and 7.15% less at an initial K2CrO4 concentration of 100 and 500 microg ml(-1) in comparison to a metal free chromium solution. K2CrO4 uptake into the plant occurred at different pHs tested, but maximum uptake was observed at pH 5. Nevertheless, the bacterial strains caused some decrease in chromate uptake into the plants, but the combined effect of plants and bacterial strains conduce more removal of Cr(VI) from the solution.

Inoculation of Schizolobium parahyba with mycorrhizal fungi and plant growth-promoting rhizobacteria increases wood yield under field conditions

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Martha Viviana Torres Cely

2016-11-01

Full Text Available Schizolobium parahyba var. amazonicum (Huber ex Ducke occurs naturally in the Brazilian Amazon. Currently, it is being planted extensively because of its fast growth and excellent use in forestry. Consequently, there is great interest in new strategies to increase wood production. The interaction between soil microorganisms and plants, specifically in the roots, provides essential nutrients for plant growth. These interactions can have growth-promoting effects. In this way, this study assessed the effect of the inoculation with arbuscular mycorrhizal fungi (AMF and plant growth-promoting rhizobacteria (PGPR on growth of S. parahyba var. amazonicum under field conditions. We used two native species of arbuscular mycorrhizal fungi, Claroideoglomus etunicatum (Ce and Acaulospora sp. (Ac; two native strains of Rhizobium sp. (Rh1 and Rh2; and a non-native strain of Burkholderia sp. Different combinations of microorganisms were supplemented with chemical fertilizers (doses D1 and D2 in two planting methods, seed sowing and seedling planting. In seed sowing, the results showed that treatments with Ce/Rh1/Fertilizer D2 and Ac/No PGPR/Fertilizer D2 increased wood yield. In seedling planting, two combinations (Ac/Rh2/Fertilizer D1 and Ac/Rh1/Fertilizer D1 were more effective in increasing seedling growth. In these experiments, inoculation with AMF and PGPR increased wood yield by about 20% compared to the application of fertilizer alone.

Inoculation of Schizolobium parahyba with Mycorrhizal Fungi and Plant Growth-Promoting Rhizobacteria Increases Wood Yield under Field Conditions.

Science.gov (United States)

Cely, Martha V T; Siviero, Marco A; Emiliano, Janaina; Spago, Flávia R; Freitas, Vanessa F; Barazetti, André R; Goya, Erika T; Lamberti, Gustavo de Souza; Dos Santos, Igor M O; De Oliveira, Admilton G; Andrade, Galdino

2016-01-01

Schizolobium parahyba var. amazonicum (Huber ex Ducke) occurs naturally in the Brazilian Amazon. Currently, it is being planted extensively because of its fast growth and excellent use in forestry. Consequently, there is great interest in new strategies to increase wood production. The interaction between soil microorganisms and plants, specifically in the roots, provides essential nutrients for plant growth. These interactions can have growth-promoting effects. In this way, this study assessed the effect of the inoculation with arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) on growth of S. parahyba var. amazonicum under field conditions. We used two native species of arbuscular mycorrhizal fungi, Claroideoglomus etunicatum (Ce), and Acaulospora sp. (Ac); two native strains of Rhizobium sp. (Rh1 and Rh2); and a non-native strain of Burkholderia sp. Different combinations of microorganisms were supplemented with chemical fertilizers (doses D1 and D2) in two planting methods, seed sowing and seedling planting. In seed sowing, the results showed that treatments with Ce/Rh1/Fertilizer D2 and Ac/No PGPR/Fertilizer D2 increased wood yield. In seedling planting, two combinations (Ac/Rh2/Fertilizer D1 and Ac/Rh1/Fertilizer D1) were more effective in increasing seedling growth. In these experiments, inoculation with AMF and PGPR increased wood yield by about 20% compared to the application of fertilizer alone.

New inoculants on maize silage fermentation

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Fábia Giovana do Val de Assis

2014-08-01

Full Text Available The objective of this study was to evaluate the effect of bacterial inoculants at two inoculation rates on chemical and biological characteristics of maize silage. The treatments consisted of two inoculating rates (5 and 6 log cfu g-1 of forage for each strain of lactic acid bacteria (LAB identified as Lactobacillus buchneri, L. hilgardii, or L. plantarum. The maize was ensiled in experimental PVC silos. Samples were taken for the determination of the contents of dry matter (DM, crude protein (CP, neutral detergent fiber (NDF, water-soluble carbohydrates (WSC, organic acids and alcohols, for the evaluation of the populations of lactic acid bacteria, yeasts, filamentous fungi, and for the determination of pH values during ensilage and after 30 or 90 days of fermentation. The doses of inoculants did not promote significant differences on the evaluated characteristics. There was effect of inoculants on acetic acid, 1.2-propanediol, LAB population, filamentous fungi, and pH value. No significant influence of the treatments with inoculants was observed in the variables DM, WSC, CP, lactic acid concentrations, or ethanol. The maximum temperature, i.e., the time to achieve the maximum temperature (TMT and aerobic stability (AS, was not influencied by treatments. However, a decrease in maximum temperature, an increase in TMT, and improvement in the AS were observed after 90 days of fermentation. These results proved the advantage of microbial inoculation. The treatments influenced LAB populations and filamentous fungi, but no effect was observed on the yeast population. The best inoculation dose is 6 cfu g-1 of forage because it provides higher reduction of filamentous fungi in maize silage, thereby decreasing the aerobic deterioration by these microorganisms.

Survival and growth of Alfalfa (Medicago sativa l.) inoculated with an am fungus (Glomus intraradices) in contaminated soils treated with two different remediation technologies (bio-pile and thermal desorption)

International Nuclear Information System (INIS)

Norini, M.P.; Beguiristain, Th.; Leyval, C.

2005-01-01

sativa L.), inoculated or not with an AM fungus (Glomus intraradices) and fertilized with Hewitt solution. Control non-inoculated and non-fertilized plants were included. There was four replicates per treatment. After 2 months, plant survival and growth was measured, as well as mycorrhizal colonization of roots. PAH in rhizosphere soils was analyzed using ASE and GC-FID. Major and trace elements in plants were analyzed after acid digestion using ICP. AM fungal and bacterial communities present in roots and rhizosphere were also analysed after DNA extraction with a PCR-TGGE technique. Plant survival rate was significantly lower in the soil treated with bio-pile than in untreated soil. Non-inoculated and non fertilized alfalfa biomass was lower with soil treated with bio-pile and thermal desorption than with untreated soil. Mycorrhizal inoculation as well as fertilization significantly improved alfalfa growth in the soil treated with bio-pile. In the soil treated with thermal desorption, shoot and root biomass were significantly higher with mycorrhizal inoculation and fertilization. Estimation of root colonization showed that the roots of un-inoculated plants growing on the untreated contaminated soil contained indigenous mycorrhizal fungi. With the soil treated with bio-pile, mycorrhizal colonization of un-inoculated plants was significantly lower, while no colonization was observed in the roots in the soil treated with thermal desorption. Inoculation with a mycorrhizal fungus increased root colonization rate in both treated soils. It also significantly increased the number of rhizobia nodules. Phosphorus concentration in plant roots and shoots was significantly improved by mycorrhizal inoculation in soil treated with thermal desorption. Data on PAH concentration in soils and fungal and bacterial communities will be also presented and discussed

Rhizospheric bacterial strain Brevibacterium casei MH8a colonizes plant tissues and enhances Cd, Zn, Cu phytoextraction by white mustard

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Tomasz ePłociniczak

2016-02-01

Full Text Available Environmental pollution by heavy metals has become a serious problem in the world. Phytoextraction, which is one of the plant-based technologies, has attracted the most attention for the bioremediation of soils polluted with these contaminants.The aim of this study was to determine whether the multiple-tolerant bacterium, Brevibacterium casei MH8a isolated from the heavy metal-contaminated rhizosphere soil of Sinapis alba L., is able to promote plant growth and enhance Cd, Zn and Cu uptake by white mustard under laboratory conditions. Additionally, the ability of the rifampicin-resistant spontaneous mutant of MH8a to colonize plant tissues and its mechanisms of plant growth promotion were also examined. In order to assess the ecological consequences of bioaugmentation on autochthonous bacteria, the phospholipid fatty acid (PLFA analysis was used. The MH8a strain exhibited the ability to produce ammonia, 1-amino-cyclopropane-1-carboxylic acid deaminase, indole 3-acetic acid and HCN but was not able to solubilize inorganic phosphate and produce siderophores. Introduction of MH8a into soil significantly increased S. alba biomass and the accumulation of Cd (208%, Zn (86% and Cu (39% in plant shoots in comparison with those grown in non-inoculated soil. Introduced into the soil, MH8a was able to enter the plant and was found in the roots and leaves of inoculated plants thus indicating its endophytic features. PLFA analysis revealed that the MH8a that was introduced into soil had a temporary influence on the structure of the autochthonous bacterial communities. The plant growth-promoting features of the MH8a strain and its ability to enhance the metal uptake by white mustard and its long-term survival in soil as well as its temporary impact on autochthonous microorganisms make the strain a suitable candidate for the promotion of plant growth and the efficiency of phytoextraction.

Cultivation-Based and Molecular Assessment of Bacterial Diversity in the Rhizosheath of Wheat under Different Crop Rotations.

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Muhammad Tahir

Full Text Available A field study was conducted to compare the formationand bacterial communities of rhizosheaths of wheat grown under wheat-cotton and wheat-rice rotation and to study the effects of bacterial inoculation on plant growth. Inoculation of Azospirillum sp. WS-1 and Bacillus sp. T-34 to wheat plants increased root length, root and shoot dry weight and dry weight of rhizosheathsoil when compared to non-inoculated control plants, and under both crop rotations. Comparing both crop rotations, root length, root and shoot dry weight and dry weight of soil attached with roots were higher under wheat-cotton rotation. Organic acids (citric acid, malic acid, acetic acid and oxalic acid were detected in rhizosheaths from both rotations, with malic acid being most abundant with 24.8±2 and 21.3±1.5 μg g(-1 dry soil in wheat-cotton and wheat-rice rotation, respectively. Two sugars (sucrose, glucose were detected in wheat rhizosheath under both rotations, with highest concentrations of sucrose (4.08±0.5 μg g(-1 and 7.36±1.0 μg g(-1 and glucose (3.12±0.5 μg g(-1 and 3.01± μg g(-1 being detected in rhizosheaths of non-inoculated control plants under both rotations. Diversity of rhizosheath-associated bacteria was evaluated by cultivation, as well as by 454-pyrosequencing of PCR-tagged 16S rRNA gene amplicons. A total of 14 and 12 bacterial isolates predominantly belonging to the genera Arthrobacter, Azospirillum, Bacillus, Enterobacter and Pseudomonaswere obtained from the rhizosheath of wheat grown under wheat-cotton and wheat-rice rotation, respectively. Analysis of pyrosequencing data revealed Proteobacteria, Bacteriodetes and Verrucomicrobia as the most abundant phyla in wheat-rice rotation, whereas Actinobacteria, Firmicutes, Chloroflexi, Acidobacteria, Planctomycetes and Cyanobacteria were predominant in wheat-cotton rotation. From a total of 46,971 sequences, 10.9% showed ≥97% similarity with 16S rRNA genes of 32 genera previously shown to include

Establishment and effectiveness of inoculated arbuscular mycorrhizal fungi in agricultural soils.

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Köhl, Luise; Lukasiewicz, Catherine E; van der Heijden, Marcel G A

2016-01-01

Arbuscular mycorrhizal fungi (AMF) are promoted as biofertilizers for sustainable agriculture. So far, most researchers have investigated the effects of AMF on plant growth under highly controlled conditions with sterilized soil, soil substrates or soils with low available P or low inoculum potential. However, it is still poorly documented whether inoculated AMF can successfully establish in field soils with native AMF communities and enhance plant growth. We inoculated grassland microcosms planted with a grass-clover mixture (Lolium multiflorum and Trifolium pratense) with the arbuscular mycorrhizal fungus Rhizoglomus irregulare. The microcosms were filled with eight different unsterilized field soils that varied greatly in soil type and chemical characteristics and indigenous AMF communities. We tested whether inoculation with AMF enhanced plant biomass and R. irregulare abundance using a species specific qPCR. Inoculation increased the abundance of R. irregulare in all soils, irrespective of soil P availability, the initial abundance of R. irregulare or the abundance of native AM fungal communities. AMF inoculation had no effect on the grass but significantly enhanced clover yield in five out of eight field soils. The results demonstrate that AMF inoculation can be successful, even when soil P availability is high and native AMF communities are abundant. © 2015 John Wiley & Sons Ltd.

Seasonal Abundance and Natural Inoculativity of Insect Vectors of Xylella fastidiosa in Oklahoma Tree Nurseries and Vineyards.

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Overall, Lisa M; Rebek, Eric J

2015-12-01

Xylella fastidiosa is the causative agent of diseases of perennial plants including peach, plum, elm, oak, pecan, and grape. This bacterial pathogen is transmitted by xylem-feeding insects. In recent years, Pierce's disease of grape has been detected in 10 counties in central and northeastern Oklahoma, prompting further investigation of the disease epidemiology in this state. We surveyed vineyards and tree nurseries in Oklahoma for potential insect vectors to determine species composition, infectivity, and natural inoculativity of commonly captured insect vectors. Yellow sticky cards were used to sample insect fauna at each location. Insects were removed from sticky cards and screened for X. fastidiosa using immunocapture-PCR to determine their infectivity. A second objective was to test the natural inoculativity of insect vectors that are found in vineyards. Graphocephala versuta (Say), Graphocephala coccinea (Forster), Paraulacizes irrorata (F.), Oncometopia orbona (F.), Cuerna costalis (F.), and Entylia carinata Germar were collected from vineyards and taken back to the lab to determine their natural inoculativity. Immunocapture-PCR was used to test plant and insect samples for presence of X. fastidiosa. The three most frequently captured species from vineyards and tree nurseries were G. versuta, Clastoptera xanthocephala Germar, and O. orbona. Of those insects screened for X. fastidiosa, 2.4% tested positive for the bacterium. Field-collected G. versuta were inoculative to both ragweed and alfalfa. Following a 7-d inoculation access period, a higher percentage of alfalfa became infected than ragweed. Results from this study provide insight into the epidemiology of X. fastidiosa in Oklahoma. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Microbial activity, arbuscular mycorrhizal fungi and inoculation of woody plants in lead contaminated soil

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Graziella S Gattai

2011-09-01

Full Text Available The goals of this study were to evaluate the microbial activity, arbuscular mycorrhizal fungi and inoculation of woody plants (Caesalpinia ferrea, Mimosa tenuiflora and Erythrina velutina in lead contaminated soil from the semi-arid region of northeastern of Brazil (Belo Jardim, Pernambuco. Dilutions were prepared by adding lead contaminated soil (270 mg Kg-1 to uncontaminated soil (37 mg Pb Kg soil-1 in the proportions of 7.5%, 15%, and 30% (v:v. The increase of lead contamination in the soil negatively influenced the amount of carbon in the microbial biomass of the samples from both the dry and rainy seasons and the metabolic quotient only differed between the collection seasons in the 30% contaminated soil. The average value of the acid phosphatase activity in the dry season was 2.3 times higher than observed during the rainy season. There was no significant difference in the number of glomerospores observed between soils and periods studied. The most probable number of infective propagules was reduced for both seasons due to the excess lead in soil. The mycorrhizal colonization rate was reduced for the three plant species assayed. The inoculation with arbuscular mycorrhizal fungi benefited the growth of Erythrina velutina in lead contaminated soil.

The influence of microbial-based inoculants on N2O emissions from soil planted with corn (Zea mays L.) under greenhouse conditions with different nitrogen fertilizer regimens.

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Calvo, Pamela; Watts, Dexter B; Kloepper, Joseph W; Torbert, H Allen

2016-12-01

Nitrous oxide (N 2 O) emissions are increasing at an unprecedented rate owing to the increased use of nitrogen (N) fertilizers. Thus, new innovative management tools are needed to reduce emissions. One potential approach is the use of microbial inoculants in agricultural production. In a previous incubation study, we observed reductions in N 2 O emissions when microbial-based inoculants were added to soil (no plants present) with N fertilizers under laboratory incubations. This present study evaluated the effects of microbial-based inoculants on N 2 O and carbon dioxide (CO 2 ) emissions when applied to soil planted with corn (Zea mays L.) under controlled greenhouse conditions. Inoculant treatments consisted of (i) SoilBuilder (SB), (ii) a metabolite extract of SoilBuilder (SBF), and (iii) a mixture of 4 strains of plant-growth-promoting Bacillus spp. (BM). Experiments included an unfertilized control and 3 N fertilizers: urea, urea - ammonium nitrate with 32% N (UAN-32), and calcium - ammonium nitrate with 17% N (CAN-17). Cumulative N 2 O fluxes from pots 41 days after planting showed significant reductions in N 2 O of 15% (SB), 41% (BM), and 28% (SBF) with CAN-17 fertilizer. When UAN-32 was used, reductions of 34% (SB), 35% (SBF), and 49% (BM) were obtained. However, no reductions in N 2 O emissions occurred with urea. Microbial-based inoculants did not affect total CO 2 emissions from any of the fertilized treatments or the unfertilized control. N uptake was increased by an average of 56% with microbial inoculants compared with the control (nonmicrobial-based treatments). Significant increases in plant height, SPAD chlorophyll readings, and fresh and dry shoot mass were also observed when the microbial-based treatments were applied (with and without N). Overall, results demonstrate that microbial inoculants can reduce N 2 O emissions following fertilizer application depending on the N fertilizer type used and can enhance N uptake and plant growth. Future

Growth and Yield Responses of Cowpea to Inoculation and Phosphorus Fertilization in Different Environments

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Kyei-Boahen, Stephen; Savala, Canon E. N.; Chikoye, David; Abaidoo, Robert

2017-01-01

Cowpea (Vigna unguiculata) is a major source of dietary protein and essential component of the cropping systems in semi-arid regions of Sub-Saharan Africa. However, yields are very low due to lack of improved cultivars, poor management practices, and limited inputs use. The objectives of this study were to assess the effects of rhizobia inoculant and P on nodulation, N accumulation and yield of two cowpea cultivars in Mozambique. Field study was conducted in three contrasting environments during the 2013/2014 and 2014/2015 seasons using randomized complete block design with four replications and four treatments. Treatments consisted of seed inoculation, application of 40 kg P2O5 ha-1, inoculation + P, and a non-inoculated control. The most probable number (MPN) technique was used to estimate the indigenous bradyrhizobia populations at the experimental sites. The rhizobia numbers at the sites varied from 5.27 × 102 to 1.07 × 103 cells g-1 soil. Inoculation increased nodule number by 34–76% and doubled nodule dry weight (78 to 160 mg plant-1). P application improved nodulation and interacted positively with the inoculant. Inoculation, P, and inoculant + P increased shoot dry weight, and shoot and grain N content across locations but increases in number of pods plant-1, seeds pod-1, and 100-seed weight were not consistent among treatments across locations. Shoot N content was consistently high for the inoculated plants and also for the inoculated + P fertilized plants, whereas the non-inoculated control plants had the lowest tissue N content. P uptake in shoot ranged from 1.72 to 3.77 g kg-1 and was higher for plants that received P fertilizer alone. Inoculation and P either alone or in combination consistently increased cowpea grain yield across locations with yields ranging from 1097 kg ha-1 for the non-inoculated control to 1674 kg ha-1 for the inoculant + P treatment. Grain protein concentration followed a similar trend as grain yield and ranged from 223 to

In-vivo electrochemical monitoring of H2O2 production induced by root-inoculated endophytic bacteria in Agave tequilana leaves.

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Lima, Alex S; Prieto, Kátia R; Santos, Carla S; Paula Valerio, Hellen; Garcia-Ochoa, Evelyn Y; Huerta-Robles, Aurora; Beltran-Garcia, Miguel J; Di Mascio, Paolo; Bertotti, Mauro

2018-01-15

A dual-function platinum disc microelectrode sensor was used for in-situ monitoring of H 2 O 2 produced in A. tequilana leaves after inoculation of their endophytic bacteria (Enterobacter cloacae). Voltammetric experiments were carried out from 0.0 to -1.0V, a potential range where H 2 O 2 is electrochemically reduced. A needle was used to create a small cavity in the upper epidermis of A. tequilana leaves, where the fabricated electrochemical sensor was inserted by using a manual three-dimensional micropositioner. Control experiments were performed with untreated plants and the obtained electrochemical results clearly proved the formation of H 2 O 2 in the leaves of plants 3h after the E. cloacae inoculation, according to a mechanism involving endogenous signaling pathways. In order to compare the sensitivity of the microelectrode sensor, the presence of H 2 O 2 was detected in the root hairs by 3,3-diaminobenzidine (DAB) stain 72h after bacterial inoculation. In-situ pH measurements were also carried out with a gold disc microelectrode modified with a film of iridium oxide and lower pH values were found in A. tequilana leaves treated with bacteria, which may indicate the plant produces acidic substances by biosynthesis of secondary metabolites. This microsensor could be an advantageous tool for further studies on the understanding of the mechanism of H 2 O 2 production during the plant-endophyte interaction. Copyright © 2017 Elsevier B.V. All rights reserved.

Xanthomonas euvesicatoria Causes Bacterial Spot Disease on Pepper Plant in Korea

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Min-Seong Kyeon

2016-10-01

Full Text Available In 2004, bacterial spot-causing xanthomonads (BSX were reclassified into 4 species—Xanthomonas euvesicatoria, X. vesicatoria, X. perforans, and X. gardneri. Bacterial spot disease on pepper plant in Korea is known to be caused by both X. axonopodis pv. vesicatoria and X. vesicatoria. Here, we reidentified the pathogen causing bacterial spots on pepper plant based on the new classification. Accordingly, 72 pathogenic isolates were obtained from the lesions on pepper plants at 42 different locations. All isolates were negative for pectolytic activity. Five isolates were positive for amylolytic activity. All of the Korean pepper isolates had a 32 kDa-protein unique to X. euvesicatoria and had the same band pattern of the rpoB gene as that of X. euvesicatoria and X. perforans as indicated by PCR-restriction fragment length polymorphism analysis. A phylogenetic tree of 16S rDNA sequences showed that all of the Korean pepper plant isolates fit into the same group as did all the reference strains of X. euvesicatoria and X. perforans. A phylogenetic tree of the nucleotide sequences of 3 housekeeping genes—gapA, gyrB, and lepA showed that all of the Korean pepper plant isolates fit into the same group as did all of the references strains of X. euvesicatoria. Based on the phenotypic and genotypic characteristics, we identified the pathogen as X. euvesicatoria. Neither X. vesicatoria, the known pathogen of pepper bacterial spot, nor X. perforans, the known pathogen of tomato plant, was isolated. Thus, we suggest that the pathogen causing bacterial spot disease of pepper plants in Korea is X. euvesicatoria.

Defense mechanisms of Solanum tuberosum L. in response to attack by plant-pathogenic bacteria

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VERA A D POIATTI

2009-01-01

Full Text Available The natural resistance of plants to disease is based not only on preformed mechanisms, but also on induced mechanisms. The defense mechanisms present in resistant plants may also be found in susceptible ones. This study attempted to analyze the metabolic alterations in plants of the potato Solanum tuberosum L. cv. Agata that were inoculated with the incompatible plant-pathogenic bacteria X. axonopodis and R. solanacearum, and the compatible bacterium E. carotovora. Levels of total phenolic compounds, including the flavonoid group, and the activities of polyphenol oxidase (PPO and peroxidase (POX were evaluated. Bacteria compatibility was evaluated by means of infiltration of tubers. The defense response was evaluated in the leaves of the potato plants. Leaves were inoculated depending on their number and location on the stem. Multiple-leaf inoculation was carried out on basal, intermediate, and apical leaves, and single inoculations on intermediate leaves. Leaves inoculated with X. axonopodis and with R. solanacearum showed hypersensitive responses within 24 hours post-inoculation, whereas leaves inoculated with E. carotovora showed disease symptoms. Therefore, the R. solanacearum isolate used in the experiments did not exhibit virulence to this potato cultivar. Regardless of the bacterial treatments, the basal leaves showed higher PPO and POX activities and lower levels of total phenolic compounds and flavonoids, compared to the apical leaves. However, basal and intermediate leaves inoculated with R. solanacearum and X. axonopodis showed increases in total phenolic compounds and flavonoid levels. In general, multiple-leaf inoculation showed the highest levels of total phenolics and flavonoids, whereas the single inoculations resulted in the highest increase in PPO activity. The POX activity showed no significant difference between single- and multiple-leaf inoculations. Plants inoculated with E. carotovora showed no significant increase in

Inoculation with arbuscular mycorrhizal fungi improves the nutritional value of tomatoes.

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Hart, Miranda; Ehret, David L; Krumbein, Angelika; Leung, Connie; Murch, Susan; Turi, Christina; Franken, Philipp

2015-07-01

Arbuscular mycorrhizal (AM) fungi can affect many different micronutrients and macronutrients in plants and also influence host volatile compound synthesis. Their effect on the edible portions of plants is less clear. Two separate studies were performed to investigate whether inoculation by AM fungi (Rhizophagus irregularis, Funneliformis mosseae, or both) can affect the food quality of tomato fruits, in particular common minerals, antioxidants, carotenoids, a suite of vitamins, and flavor compounds (sugars, titratable acids, volatile compounds). It was found that AM fungal inoculation increased the nutrient quality of tomato fruits for most nutrients except vitamins. Fruit mineral concentration increased with inoculation (particularly N, P, and Cu). Similarly, inoculated plants had fruit with higher antioxidant capacity and more carotenoids. Furthermore, five volatile compounds were significantly higher in AM plants compared with non-AM controls. Taken together, these results show that AM fungi represent a promising resource for improving both sustainable food production and human nutritional needs.

Reduced Bacterial Wilt in Tomato Plants by Bactericidal Peroxyacetic Acid Mixture Treatment

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Jeum Kyu Hong

2018-02-01

Full Text Available Peroxyacetic acid mixture Perosan, composed of peroxyacetic acid, hydrogen peroxide and acetic acid, was evaluated for eco-friendly management of tomato bacterial wilt by Ralstonia pseudosolanacearum. Perosan drastically suppressed in vitro growth of R. pseudosolanacearum in liquid cultures in dose- and incubation time-dependent manners. Higher perosan doses (0.1 and 1% caused lowered pH and phytotoxicity to detached leaves of two tomato cultivars Cupirang and Benekia 220 in aqueous solution. Treatment with 0.01% of Perosan delayed wilting symptom significantly in the detached leaves of two cultivars inoculated with R. pseudosolanacearum (10⁷ cfu/ml. Soil drenching of 5% Perosan solution in pots caused severe tissue collapse of tomato seedlings at the four-week-old stage of two tomato cultivars. Treatment with 1% Perosan by soil-drenching significantly reduced bacterial wilt in the tomato seedlings of two cultivars. These findings suggest that Perosan treatment can be applied to suppress bacterial wilt during tomato production.

Plant growth promotion properties of bacterial strains isolated from the rhizosphere of the Jerusalem artichoke (Helianthus tuberosus L.) adapted to saline-alkaline soils and their effect on wheat growth.

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Liu, Xiaolin; Li, Xiangyue; Li, Yan; Li, Runzhi; Xie, Zhihong

2017-03-01

The Jerusalem artichoke (JA; Helianthus tuberosus), known to be tolerant to saline-alkaline soil conditions, has been cultivated for many years in the Yellow River delta, Shandong Province coastal zone, in China. The aim of our study was to isolate nitrogen-fixing bacteria colonizing the rhizosphere of JA and to characterize other plant growth promotion properties. The ultimate goal was to identify isolates that could be used as inoculants benefiting an economic crop, in particular for improving wheat growth production in the Yellow River delta. Bacterial strains were isolated from the rhizosphere soil of JA on the basis of growth on nitrogen-free Ashby medium. Identification and phylogenetic analysis was performed after nucleotide sequencing of 16S rRNA gene. Plant-growth-promoting traits, such as nitrogen fixation activity, phosphate solubilization activity, indole-3-acetic acid production, were determined using conventional methods. Eleven strains were isolated and 6 of them were further examined for their level of salt tolerance and their effect on plant growth promotion. Inoculation of Enterobacter sp. strain N10 on JA and wheat led to significant increases in both root and shoot dry mass and shoot height. Enterobacter sp. strain N10 appeared to be the best plant-growth-promoting rhizobacteria to increase wheat productivity in future field applications.

Chromium Resistant Bacteria: Impact on Plant Growth in Soil Microcosm

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Sayel Hanane

2014-07-01

Full Text Available Three chromium resistant bacterial strains, Pseudomonas fluorescens PF28, Enterobacter amnigenus EA31 and Enterococcus gallinarum S34 isolated from tannery waste contaminated soil were used in this study. All strains could resist a high concentration of K2Cr2O7 that is up to 300 mg/L. The effect of these strains on clover plants (Trifolium campestre in the presence of two chromium salts CrCl3 and K2Cr2O7 was studied in soil microcosm. Application of chromium salts adversely affected seed germination, root and shoot length. Bacterial inoculation improved the growth parameters under chromate stress when compared with non inoculated respective controls. There was observed more than 50% reduction of Cr(VI in inoculated soil microcosms, as compared to the uninoculated soil under the same conditions. The results obtained in this study are significant for the bioremediation of chromate pollution.

Bacterial siderophores efficiently provide iron to iron-starved tomato plants in hydroponics culture.

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Radzki, W; Gutierrez Mañero, F J; Algar, E; Lucas García, J A; García-Villaraco, A; Ramos Solano, B

2013-09-01

Iron is one of the essential elements for a proper plant development. Providing plants with an accessible form of iron is crucial when it is scant or unavailable in soils. Chemical chelates are the only current alternative and are highly stable in soils, therefore, posing a threat to drinking water. The aim of this investigation was to quantify siderophores produced by two bacterial strains and to determine if these bacterial siderophores would palliate chlorotic symptoms of iron-starved tomato plants. For this purpose, siderophore production in MM9 medium by two selected bacterial strains was quantified, and the best was used for biological assay. Bacterial culture media free of bacteria (S) and with bacterial cells (BS), both supplemented with Fe were delivered to 12-week-old plants grown under iron starvation in hydroponic conditions; controls with full Hoagland solution, iron-free Hoagland solution and water were also conducted. Treatments were applied twice along the experiment, with a week in between. At harvest, plant yield, chlorophyll content and nutritional status in leaves were measured. Both the bacterial siderophore treatments significantly increased plant yield, chlorophyll and iron content over the positive controls with full Hoagland solution, indicating that siderophores are effective in providing Fe to the plant, either with or without the presence of bacteria. In summary, siderophores from strain Chryseobacterium C138 are effective in supplying Fe to iron-starved tomato plants by the roots, either with or without the presence of bacteria. Based on the amount of siderophores produced, an effective and economically feasible organic Fe chelator could be developed.

Necessity of mycorrhizal re-inoculation in the transplantation of banana in areas with precedent of inoculated canavalia with AMF

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Jaime Enrique Simó González

2016-07-01

Full Text Available From being the banana, a mycotrophic crop and previous results on the potential of green manure inoculated as a way to mycorrhizal economic crops, this work was developed in order to assess whether a precedent Canavalia ensiformis cultivation, inoculated with efficient strains of arbuscular mycorrhizal fungi (AMF inoculation, it is necessary the banana inoculation, ‘FHIA-18’ (AAAB cultivar in the transplant field. Four treatments were evaluated: a control without application of fertilizers and other organic-mineral fertilizers (100% FOM, both without canavalia and two other treatments that are used above canavalia inoculated AMF and half also received organic-mineral fertilizer applications: (50% FOM, one of which, the banana was reinoculated in the transplant field and the other one not. The experimental design used, was randomized blocks, with four replications. The experiment ended after three productive cycles (mother plant, stems 1 and 2. Canavalia inoculated treatments and 50 % of FOM, guaranteed high yields and satisfactory nutritional content similar to that received 100 % of FOM and significantly higher than those obtained with the control treatment. This together with the values of colonization percentages and pores at both high and inoculated treatments were no significant differences between them, indicated not only the effectiveness of mycorrhizal inoculation but rather green manure inoculation was successful to inoculate bananas and re-inoculation of the same was not needed on the transplant.

Biochar and flyash inoculated with plant growth promoting rhizobacteria act as potential biofertilizer for luxuriant growth and yield of tomato plant.

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Tripti; Kumar, Adarsh; Usmani, Zeba; Kumar, Vipin; Anshumali

2017-04-01

Overuse of agrochemical fertilizers alarmingly causes deterioration in soil health and soil-flora. Persistence of these agrochemicals exerts detrimental effects on environment, potentially inducing toxic effects on human health, thus pronouncing an urgent need for a safer substitute. The present study investigates the potential use of agricultural and industrial wastes as carrier materials, viz. biochar and flyash, respectively, for preparation of bioformulations (or biofertilizers) using two plant growth promoting rhizobacteria, Bacillus sp. strain A30 and Burkholderia sp. strain L2, and its effect on growth of Lycopersicon esculentum Mill. (tomato). The viability of strains was determined based on colony forming units (cfu) count of each bioformulation at an interval of 60 days for a period of 240 days. Seeds were coated with different carrier based bioformulations and pot experiment(s) were carried out to access its effects on plant growth parameters. Biochar based bioformulations showed higher cfu count and maximum viability for strain L2 (10 7  cfu g -1 ) at 240 days of storage. Maximum percentage of seed germination was also observed in biochar inoculated with strain L2. Significant (p < 0.05) increase in plant growth parameters (dry and fresh biomass, length, number of flowers) were ascertained from the pot experiment and amongst all bioformulations, biochar inoculated with strain L2 performed consistently thriving results for tomato yield. Furthermore, post-harvest study of this bioformulation treated soil improved physico-chemical properties and dehydrogenase activity as compared to pre-plantation soil status. Overall, we show that prepared biochar based bioformulation using Burkholderia sp. L2 as inoculum can tremendously enhance the productivity of tomato, soil fertility, and can also act as a sustainable substitute for chemical fertilizers. In addition, mixture of biochar and flyash inoculated with strain L2 also showed noteworthy results for the

Selection of diazotrophic bacteria isolated from wastewater treatment plant sludge at a poultry slaughterhouse for their effect on maize plants

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Jorge Avelino Rodriguez Lozada

Full Text Available ABSTRACT The economic and environmental costs of nitrogen fertilization have intensified the search for technologies that reduce mineral fertilization, for example atmospheric nitrogen-fixing (diazotrophic bacteria inoculation. In this context, the present study addressed the isolation and quantification of diazotrophic bacteria in the sludge from treated wastewater of a poultry slaughterhouse; a description of the bacteria, based on cell and colony morphology; and an assessment of growth and N content of maize plants in response to inoculation. Sixteen morphotypes of bacteria were isolated in six N-free culture media (JMV, JMVL, NFb, JNFb, LGI, and LGI-P. The bacteria stained gram-positive, with 10 rod- and six coccoid-shaped isolates. To evaluate the potential of bacteria to promote plant growth, maize seeds were inoculated. The experiment consisted of 17 treatments (control plus 16 bacterial isolates and was carried out in a completely randomized design with six replicates. The experimental units consisted of one pot containing two maize plants in a greenhouse. Forty-five days after planting, the variables plant height, leaf number, stem diameter, root and shoot fresh and dry weight, and N content were measured. The highest values were obtained with isolate UFV L-162, which produced 0.68 g total dry matter per plant and increased N content to 22.14 mg/plant, representing increments of 74 and 133%, respectively, compared with the control. Diazotrophs inhabit sludge from treated wastewater of poultry slaughterhouses and can potentially be used to stimulate plant development and enrich inoculants.

Influence of arbuscular mycorrhizal fungi, rhizobium inoculation and rock phosphate on growth and quality of lentil

International Nuclear Information System (INIS)

Yaseen, T.; Ali, K.

2016-01-01

Effective inoculation of legumes has the ability not only to ensure nutrients availability to plants particularly in N and P-limiting (due to improvement in nutrients fixation) environments but also can manipulate the environmental hazards associated with over inorganic fertilization. To support this view, the current experiment was conducted to study the influence of rock phosphorus fertilization, Arbuscular Mycorrhizae (AM) and Rhizobium inoculation on growth and yield parameters of Lens culinaris (NARC.2008-4). In addition, the current experiments aimed to evaluate the effect of different inoculation practices on crop quality in comparison with control (no inoculation).The experiment was laid out in randomized complete block design with four replications during winter (2010-11 and 2012-13) at the Department of Botany University of Peshawar Pakistan. Overall, inoculated plant performed superior in terms of plant growth and quality over control. All plants measured parameters (Leaf chlorophyll content, seed protein, fiber and ash content, plant height, number of seed pod-1, leaves plant-1, flowers plant-1, pods plant-1, pod length and thousand seed weight) were highest in plant samples inoculated with VAM and Rhizobium in combination as compared to sole application of VAM or Rhizobium. Combined inoculation of VAM and Rhizobium caused 10, 24, 17, 21 and 14% increase in seed protein content, leaf chlorophyll content, seed fiber content, seed ash content and number of seed pod-1 over sole application of VAM and Rhizobium when averaged over two years. Combined application of Rhizobium + VAM enhanced seed yield plant-1 by 45% over control and 24% and 28% over sole inoculation of VAM and Rhizobium respectively. It is therefore concluded that dual inoculation of VAM + Rhizobium and rock phosphate may be of only limited consequence in high input agricultural systems. (author)

Characterization of Effective Rhizobacteria Isolated from Velvet Bean (Mucuna Pruriens) to Enhance Plant Growth

International Nuclear Information System (INIS)

Saleem, A. R.; Mahmood, T.; Batool, A.; Khalid, A.

2016-01-01

Rhizobacteria with plant growth promoting ability exist in association with plant roots and ameliorate over all plant development and yield. Numerous species of rhizobacteria have been identified with plant growth promoting ability, which can be attributed to multiple microbial characteristics. In the current study rhizobacterial isolates with best plant growth promotion traits were subjected to screening for plant growth promotion under axenic condition. The results of lab assays revealed that out of five rhizobacterial isolates three of bacterial isolate were Gram -ve and two of them were Gram +ve bacterial group. All isolates found positive for the auxin production and ACC-demainase activity. The isolate HS9 showed highest ACC activity (331 ketobutyrate nmol mg-1 biomass hr-1) and auxin production (3.85 without L-TRP). PGPR increase plant growth by reducing the ethylene release and its inhibitory effects, the role of isolates to decrease ethylene effects was affirmed via classical triple response assay on velvet bean. Furthermore, isolate were assessed for resistance test, three efficient strains (G9, HS9 and H38) exhibited antibiotic resistance for streptomycin, kanamycin and rifampicin at 100 mg L-1in TSB medium. For the purpose of co-inoculation, all three isolates showed positive relation to grow together. The results concluded that rhizobacteria selected from rain fed areas were found effective to improve plant growth with their multiple growth enhancing traits. Therefore, PGPR with various characteristics could be a better option for inoculation and co-inoculation to improve plant growth in well watered and water stressed environment. (author)

Linear-motion tattoo machine and prefabricated needle sets for the delivery of plant viruses by vascular puncture inoculation

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Vascular puncture inoculation (VPI) of plant viruses previously has been conducted either manually or by use of a commercial engraving tool and laboratory-fabricated needle arrays. In an effort to improve this technique, a linear-motion tattoo machine driving industry-standard needle arrays was tes...

Foliar Application of the Fungicide Pyraclostrobin Reduced Bacterial Spot Disease of Pepper

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Beom Ryong Kang

2018-03-01

Full Text Available Pyraclostrobin is a broad-spectrum fungicide that inhibits mitochondrial respiration. However, it may also induce systemic resistance effective against bacterial and viral diseases. In this study, we evaluated whether pyraclostrobin enhanced resistance against the bacterial spot pathogen, Xanthomonas euvesicatora on pepper (Capsicum annuum. Although pyraclostrobin alone did not suppressed the in vitro growth of X. euvesicatoria, disease severity in pepper was significantly lower by 69% after treatments with pyraclostrobin alone. A combination of pyraclostrobin with streptomycin reduced disease by over 90% that of the control plants. The preventive control of the pyraclostrobin against bacterial spot was required application 1-3 days before pathogen inoculation. Our findings suggest that the fungicide pyraclostrobin can be used with a chemical pesticide to control bacterial leaf spot diseases in pepper.

Co-inoculation with rhizobia and AMF inhibited soybean red crown rot: from field study to plant defense-related gene expression analysis.

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Xiang Gao

Full Text Available Soybean red crown rot is a major soil-borne disease all over the world, which severely affects soybean production. Efficient and sustainable methods are strongly desired to control the soil-borne diseases.We firstly investigated the disease incidence and index of soybean red crown rot under different phosphorus (P additions in field and found that the natural inoculation of rhizobia and arbuscular mycorrhizal fungi (AMF could affect soybean red crown rot, particularly without P addition. Further studies in sand culture experiments showed that inoculation with rhizobia or AMF significantly decreased severity and incidence of soybean red crown rot, especially for co-inoculation with rhizobia and AMF at low P. The root colony forming unit (CFU decreased over 50% when inoculated by rhizobia and/or AMF at low P. However, P addition only enhanced CFU when inoculated with AMF. Furthermore, root exudates of soybean inoculated with rhizobia and/or AMF significantly inhibited pathogen growth and reproduction. Quantitative RT-PCR results indicated that the transcripts of the most tested pathogen defense-related (PR genes in roots were significantly increased by rhizobium and/or AMF inoculation. Among them, PR2, PR3, PR4 and PR10 reached the highest level with co-inoculation of rhizobium and AMF.Our results indicated that inoculation with rhizobia and AMF could directly inhibit pathogen growth and reproduction, and activate the plant overall defense system through increasing PR gene expressions. Combined with optimal P fertilization, inoculation with rhizobia and AMF could be considered as an efficient method to control soybean red crown rot in acid soils.

Inoculation, colonization and distribution of fungal endophytes in ...

African Journals Online (AJOL)

Mo

and for a part or whole of their life cycle live symptomlessly within the plant. ... inoculated in tissue culture banana plants, must occur at high frequencies in the plant and be able to persist in ... For instance, the influence of fungal endophytes.

Legume bioactive compounds: influence of rhizobial inoculation

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Luis R. Silva

2017-04-01

Full Text Available Legumes consumption has been recognized as beneficial for human health, due to their content in proteins, fiber, minerals and vitamins, and their cultivation as beneficial for sustainable agriculture due to their ability to fix atmospheric nitrogen in symbiosis with soil bacteria known as rhizobia. The inoculation with these baceria induces metabolic changes in the plant, from which the more studied to date are the increases in the nitrogen and protein contents, and has been exploited in agriculture to improve the crop yield of several legumes. Nevertheless, legumes also contain several bioactive compounds such as polysaccharides, bioactive peptides, isoflavones and other phenolic compounds, carotenoids, tocopherols and fatty acids, which makes them functional foods included into the nutraceutical products. Therefore, the study of the effect of the rhizobial inoculation in the legume bioactive compounds content is gaining interest in the last decade. Several works reported that the inoculation of different genera and species of rhizobia in several grain legumes, such as soybean, cowpea, chickpea, faba bean or peanut, produced increases in the antioxidant potential and in the content of some bioactive compounds, such as phenolics, flavonoids, organic acids, proteins and fatty acids. Therefore, the rhizobial inoculation is a good tool to enhance the yield and quality of legumes and further studies on this field will allow us to have plant probiotic bacteria that promote the plant growth of legumes improving their functionality.

AMF Inoculation Enhances Growth and Improves the Nutrient Uptake Rates of Transplanted, Salt-Stressed Tomato Seedlings

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Astrit Balliu

2015-12-01

Full Text Available The study aimed to investigate the effects of commercially available AMF inoculate (Glomus sp. mixture on the growth and the nutrient acquisition in tomato (Solanumlycopersicum L. plants directly after transplanting and under different levels of salinity. Inoculated (AMF+ and non-inoculated (AMF− tomato plants were subjected to three levels of NaCl salinity (0, 50, and 100 mM·NaCl. Seven days after transplanting, plants were analyzed for dry matter and RGR of whole plants and root systems. Leaf tissue was analyzed for mineral concentration before and after transplanting; leaf nutrient content and relative uptake rates (RUR were calculated. AMF inoculation did not affect plant dry matter or RGR under fresh water-irrigation. The growth rate of AMF−plants did significantly decline under both moderate (77% and severe (61% salt stress compared to the fresh water-irrigated controls, while the decline was much less (88% and 75%,respectivelyand statistically non-significant in salt-stressed AMF+ plants. Interestingly, root system dry matter of AMF+ plants (0.098 g plant–1 remained significantly greater under severe soil salinity compared to non-inoculated seedlings (0.082 g plant–1. The relative uptake rates of N, P, Mg, Ca, Mn, and Fe were enhanced in inoculated tomato seedlings and remained higher under (moderate salt stress compared to AMF− plants This study suggests that inoculation with commercial AMF during nursery establishment contributes to alleviation of salt stress by maintaining a favorable nutrient profile. Therefore, nursery inoculation seems to be a viable solution to attenuate the effects of increasing soil salinity levels, especially in greenhouses with low natural abundance of AMF spores.

Selection of rhizosphere local microbial as bioactive inoculant based on irradiated compost

International Nuclear Information System (INIS)

Dadang Sudrajat; Nana Mulyana; Arief Adhari

2014-01-01

One of the main components of carrier based on irradiation compost for bio organic fertilizer is a potential microbial isolates role in nutrient supply and growth hormone. This research was conducted to obtain microbial isolates from plant root zone (rhizosphere), further isolation and selection in order to obtain potential isolates capable of nitrogen fixation (N 2 ), resulting in growth hormone (Indole Acetic Acid), and phosphate solubilizing. Selected potential isolates used as bioactive microbial inoculants formulation in irradiation compost based. Forty eight (48) rhizosphere samples were collected from different areas of West and Central Java. One hundred sixteen (116) isolates have been characterized for their morphological, cultural, staining and biochemical characteristics. Isolates have been selected for further screening of PGPR traits. Parameters assessed were Indole Acetic Acid (IAA) content analysis with colorimetric methods, dinitrogen fixation using gas chromatography, phosphate solubility test qualitatively (in the media pikovskaya) and quantitative assay of dissolved phosphate (spectrophotometry). Evaluation of the ability of selected isolates on the growth of corn plants were done in pots. The isolates will be used as inoculant consortium base on compost irradiation. The selection obtained eight (8) bacterial isolates identified as Bacillus circulans (3 isolates), Bacillus stearothermophilus (1 isolate), Azotobacter sp (3 isolates), Pseudomonas diminuta (1 isolate). The highest phosphate released (91,21 mg/l) was by BD2 isolate (Bacillus circulan) with a holo zone size (1.32 cm) on Pikovskaya agar medium. Isolate of Pseudomonas diminuta (KACI) was capable to produce the highest IAA hormone (74.34 μg/ml). The highest nitrogen (N 2 ) fixation activity was shown by Azotobacter sp isolates (KDB2) at a rate of 235.05 nmol/hour. The viability test showed that all selected isolates in compost irradiation carrier slightly decreased after 3 months of

Inoculation with Azospirillum sp. and Herbaspirillum sp. Bacteria Increases the Tolerance of Maize to Drought Stress.

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Curá, José Alfredo; Franz, Diego Reinaldo; Filosofía, Julián Ezequiel; Balestrasse, Karina Beatríz; Burgueño, Lautaro Exequiel

2017-07-26

Stress drought is an important abiotic factor that leads to immense losses in crop yields around the world. Strategies are urgently needed to help plants adapt to drought in order to mitigate crop losses. Here we investigated the bioprotective effects of inoculating corn grown under drought conditions with two types of plant growth-promoting rhizobacteria (PGPR), A. brasilense , strain SP-7, and H. seropedicae , strain Z-152. Plants inoculated with the bacteria were grown in a greenhouse with perlite as a substrate. Two hydric conditions were tested: normal well-watered conditions and drought conditions. Compared to control non-inoculated plants, those that were inoculated with PGPR bacteria showed a higher tolerance to the negative effects of water stress in drought conditions, with higher biomass production; higher carbon, nitrogen, and chlorophyll levels; and lower levels of abscisic acid and ethylene, which are plant hormones that affect the stress response. The oxidative stress levels of these plants were similar to those of non-inoculated plants grown in well-watered conditions, showing fewer injuries to the cell membrane. We also noted higher relative water content in the vegetal tissue and better osmoregulation in drought conditions in inoculated plants, as reflected by significantly lower proline content. Finally, we observed lower gene expression of ZmVP14 in the inoculated plants; notably, ZmVP14 is involved in the biosynthesis of abscisic acid. Taken together, these results demonstrate that these bacteria could be used to help plants cope with the negative effects of drought stress conditions.

Influence of photoperiod duration and phloem disruption through scoring on growth, disease symptoms and bacterial titer in citrus graft-inoculated with Candidatus Liberibacter asiaticus

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Plants inoculated with the huanglongbing (HLB)-associated bacterium, Candidatus Liberibacter asiaticus (CLas) are typically monitored for 8-10 months to identify differences in susceptibility between genotypes. A previous report indicated that continuous light accelerated development of HLB symptoms...

Efficacy of a Blend of Sulfuric Acid and Sodium Sulfate against Shiga Toxin-Producing Escherichia coli, Salmonella, and Nonpathogenic Escherichia coli Biotype I on Inoculated Prerigor Beef Surface Tissue.

Science.gov (United States)

Scott-Bullard, Britteny R; Geornaras, Ifigenia; Delmore, Robert J; Woerner, Dale R; Reagan, James O; Morgan, J Bred; Belk, Keith E

2017-12-01

A study was conducted to investigate the efficacy of a sulfuric acid-sodium sulfate blend (SSS) against Escherichia coli O157:H7, non-O157 Shiga toxin-producing E. coli (STEC), Salmonella, and nonpathogenic E. coli biotype I on prerigor beef surface tissue. The suitability of using the nonpathogenic E. coli as a surrogate for in-plant validation studies was also determined by comparing the data obtained for the nonpathogenic inoculum with those for the pathogenic inocula. Prerigor beef tissue samples (10 by 10 cm) were inoculated (ca. 6 log CFU/cm 2 ) on the adipose side in a laboratory-scale spray cabinet with multistrain mixtures of E. coli O157:H7 (5 strains), non-O157 STEC (12 strains), Salmonella (6 strains), or E. coli biotype I (5 strains). Treatment parameters evaluated were two SSS pH values (1.5 and 1.0) and two spray application pressures (13 and 22 lb/in 2 ). Untreated inoculated beef tissue samples served as controls for initial bacterial populations. Overall, the SSS treatments lowered inoculated (6.1 to 6.4 log CFU/cm 2 ) bacterial populations by 0.6 to 1.5 log CFU/cm 2 (P SSS was applied to samples inoculated with any of the tested E. coli inocula; however, solution pH did have a significant effect (P SSS was applied to samples inoculated with Salmonella. Results indicated that the response of the nonpathogenic E. coli inoculum to the SSS treatments was similar (P ≥ 0.05) to that of the pathogenic inocula tested, making the E. coli biotype I strains viable surrogate organisms for in-plant validation of SSS efficacy on beef. The application of SSS at the tested parameters to prerigor beef surface tissue may be an effective intervention for controlling pathogens in a commercial beef harvest process.

Effects of Bacillus amyloliquefaciens FZB42 on lettuce growth and health under pathogen pressure and its impact on the rhizosphere bacterial community.

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Soumitra Paul Chowdhury

Full Text Available The soil-borne pathogen Rhizoctonia solani is responsible for crop losses on a wide range of important crops worldwide. The lack of effective control strategies and the increasing demand for organically grown food has stimulated research on biological control. The aim of the present study was to evaluate the rhizosphere competence of the commercially available inoculant Bacillus amyloliquefaciens FZB42 on lettuce growth and health together with its impact on the indigenous rhizosphere bacterial community in field and pot experiments. Results of both experiments demonstrated that FZB42 is able to effectively colonize the rhizosphere (7.45 to 6.61 Log 10 CFU g(-1 root dry mass within the growth period of lettuce in the field. The disease severity (DS of bottom rot on lettuce was significantly reduced from severe symptoms with DS category 5 to slight symptom expression with DS category 3 on average through treatment of young plants with FZB42 before and after planting. The 16S rRNA gene based fingerprinting method terminal restriction fragment length polymorphism (T-RFLP showed that the treatment with FZB42 did not have a major impact on the indigenous rhizosphere bacterial community. However, the bacterial community showed a clear temporal shift. The results also indicated that the pathogen R. solani AG1-IB affects the rhizosphere microbial community after inoculation. Thus, we revealed that the inoculant FZB42 could establish itself successfully in the rhizosphere without showing any durable effect on the rhizosphere bacterial community.

Ectomycorrhizal inoculation with Pisolithus tinctorius reduces stress induced by drought in cork oak.

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Sebastiana, Mónica; da Silva, Anabela Bernardes; Matos, Ana Rita; Alcântara, André; Silvestre, Susana; Malhó, Rui

2018-04-01

We investigated whether the performance of cork oak under drought could be improved by colonization with the ectomycorrhizal fungus Pisolithus tinctorius. Results show that inoculation alone had a positive effect on plant height, shoot biomass, shoot basal diameter, and root growth. Under drought, root growth of mycorrhizal plants was significantly increased showing that inoculation was effective in increasing tolerance to drought. In accordance, mycorrhizal plants subjected to drought showed less symptoms of stress when compared to non-mycorrhizal plants, such as lower concentration of soluble sugars and starch, increased ability to maintain fatty acid content and composition, and increased unsaturation level of membrane lipids. After testing some of the mechanisms suggested to contribute to the enhanced tolerance of mycorrhizal plants to drought, we could not find any by which Pisolithus tinctorius could benefit cork oak, at least under the drought conditions imposed in our experiment. Inoculation did not increase photosynthesis under drought, suggesting no effect in sustaining stomatal opening at low soil water content. Similarly, plant water status was not affected by inoculation suggesting that P. tinctorius does not contribute to an increased plant water uptake during drought. Inoculation did increase nitrogen concentration in plants but it was independent of the water status. Furthermore, no significant mycorrhizal effect on drought-induced ROS production or osmotic adjustment was detected, suggesting that these factors are not important for the improved drought tolerance triggered by P. tinctorius.

Metabolic response induced by endophytic fungi and bacteria in H. marrubioides Epling in vitro micro plants

International Nuclear Information System (INIS)

Vitorino, Luciana Cristina; Silva, Fabiano Guimaraes; Lima, William Cardoso; Soares, Marcos Antonio; Pedroso, Rita Cassia Nascimento; Silva, Maroli Rodrigues; Dias, Herbert Junior; Crotti, Antonio Eduardo Miller; Silva, Marcio Luis Andrade e; Cunha, Wilson Roberto; Pauletti, Patricia Mendonca; Januario, Ana Helena

2013-01-01

Hyptis marrubioides Epling is a native plant from Brazilian Cerrado. In this paper, the response of in vitro micro plants of this species to inoculation with bacterial and fungal endophytic isolates is evaluated. HPLC-DAD analysis showed the presence of 3,4-O-(Z)-dicaffeoylquinic acid and quercetin-7-O-glucoside as the main components. GC/MS analysis demonstrated that the sesquiterpenes τ-cadinol and caryophyllene oxide were only produced in micro plants inoculated with endophytic bacteria, while methyl hexadecanoate, methyl heptadecanoate and methyl (Z,Z,Z) 9,12,15-octadecatrienoate and the triterpene methyl 3β-hydroxy-urs-12-en-28-oate were over expressed only when the micro plant was treated with endophytic fungi. (author)

Comparison of bacterial and fungal communities between natural and planted pine forests in subtropical China.

Science.gov (United States)

Nie, Ming; Meng, Han; Li, Ke; Wan, Jia-Rong; Quan, Zhe-Xue; Fang, Chang-Ming; Chen, Jia-Kuan; Li, Bo

2012-01-01

To improve our understanding of the changes in bacterial and fungal diversity in natural pine and planted forests in subtropical region of China, we examined bacterial and fungal communities from a native and a nearby planted pine forest of the Mt. Lushan by constructing clone libraries of 16S and 18S rRNA genes. For bacterial communities, Proteobacteria and Acidobacteria were dominant bacterial taxa in both two types of forest soils. The Shannon-Wiener diversity index, rarefaction curve analysis, and LibShuff analysis suggest that these two forests contained similar diversity of bacterial communities. Low soil acidity (pH ≈ 4) of our study forests might be one of the most important selection factors determining growth of acidophilic Acidobacteria and Proteobacteria. However, the natural forest harbored greater level of fungal diversity than the planted forest according to the Shannon-Wiener diversity index and rarefaction curve analysis. Basidiomycota and Ascomycota were dominant fungal taxa in the soils of natural and planted forests, respectively. Our results suggest that fungal community was more sensitive than the bacterial community in characterizing the differences in plant cover impacts on the microbial flora in the natural and planted forests. The natural and planted forests may function differently due to the differences in soil fungal diversity and relative abundance.

Response of Phaseolus vulgaris cv. Mantequilla to inoculation of Rhizobium native strains of the Ecuador in greenhouse native races of the Ecuador

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Klever Iván Granda Mora

2016-10-01

Full Text Available The development of biofertilizers based on Rhizobium strains for common bean (Phaseolus vulgaris L. requires studies about bacterial interaction with target cultivars. For these reason, the aim of this paper was to determine the effect of the inoculation of Rhizobium native strains, isolated from southern Ecuador, on P. vulgaris cultivar Mantequilla. An assay was performed in greenhouse. It were evaluated the parameters of nodulation, biomass, nitrogen fixation and efficiency of the symbiosis. All inoculated strains were able to nodulate bean seedlings. The total number of nodules, nodular biomass and plant biomass, were favourably affected by inoculation of Rhizobium strains. The best results were obtained with R. mesoamericanum NAM1, R. leguminosarum COL 6 and R. etli PIN 1 strains. The experimental evidences shows the potential of native strains of Rhizobium for it use as biofertilizers because they are able to raise the rates of nitrogen fixation in common bean in southern Ecuador.

Evaluation of the biological nitrogen fixation contribution in sugarcane plants originated from seeds and inoculated with nitrogen-fixing endophytes Avaliação da contribuição da fixação biológica de nitrogênio em cana-de-açúcar originada de sementes e inoculada com endófitos fixadores de nitrogênio

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Erineudo de Lima Canuto

2003-11-01

Full Text Available The inoculation technique with endophytic diazotrophic bacteria in sugarcane has been shown as an alternative practice to plant growth promotion. The aim of this work was to evaluate the biological nitrogen fixation (BNF contribution by different strains of Herbaspirillum seropedicae and Gluconacetobacter diazotrophicus in sugarcane plant inoculated from seeds. The seeds were planted in pots filled with non-sterile soil, inoculated with the bacterial strains and grown 10 months outside of the greenhouse. The BNF contribution of the inoculated bacteria varied depending on the plant species used as a control. The highest BNF contribution as well as the highest populations of reisolated bacteria was observed with inoculation of H. seropedicae strains. The roots appeared to be the preferential tissues for the establishment of the inoculated species.A técnica de inoculação com bactérias diazotróficas endofíticas na cana-de-açúcar apresenta-se como uma prática alternativa para promover o crescimento vegetal menos dependente da adubação nitrogenada. Este trabalho teve como objetivo avaliar a contribuição da fixação biológica de nitrogênio (FBN por diferentes estirpes de Herbaspirillum seropedicae e Gluconacetobacter diazotrophicus inoculadas em plantas de cana-de-açúcar originadas de semente. As sementes foram plantadas em vasos com solo não estéril, inoculadas com as diferentes bactérias e mantidas por 10 meses ao ar livre. As maiores contribuições da FBN ocorreram com a inoculação de estirpes Herbaspirillum seropedicae, e dependeram da espécie vegetal utilizada como testemunha. As raízes apresentaram-se como o órgão vegetal preferencial para o estabelecimento das espécies inoculadas.

Leaf bacterial diversity mediates plant diversity and ecosystem function relationships.

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Laforest-Lapointe, Isabelle; Paquette, Alain; Messier, Christian; Kembel, Steven W

2017-06-01

Research on biodiversity and ecosystem functioning has demonstrated links between plant diversity and ecosystem functions such as productivity. At other trophic levels, the plant microbiome has been shown to influence host plant fitness and function, and host-associated microbes have been proposed to influence ecosystem function through their role in defining the extended phenotype of host organisms However, the importance of the plant microbiome for ecosystem function has not been quantified in the context of the known importance of plant diversity and traits. Here, using a tree biodiversity-ecosystem functioning experiment, we provide strong support for the hypothesis that leaf bacterial diversity is positively linked to ecosystem productivity, even after accounting for the role of plant diversity. Our results also show that host species identity, functional identity and functional diversity are the main determinants of leaf bacterial community structure and diversity. Our study provides evidence of a positive correlation between plant-associated microbial diversity and terrestrial ecosystem productivity, and a new mechanism by which models of biodiversity-ecosystem functioning relationships can be improved.

Transfer of bacterial blight resistance from Oryza meyeriana to O.Sativa L.by asymmetric somatic hybridization

Institute of Scientific and Technical Information of China (English)

ZHU Yongsheng; CHEN Baotang; YU Shunwu; ZHANG Duanpin; ZHANG Xueqin; YAN Qiusheng

2004-01-01

Asymmetric somatic hybrid plants were produced between cultivated rice (Oryza sativa L.) and wild species [O. Meyeriana (Zoll. etMor, exSteud.)] with high resistance to rice bacterial blight. X-ray-irradiated protoplasts of the wild species were used as donor and chemically fused with iodoacetamide-inactivated protoplasts of rice cv. 02428to produce hybrids. Seventy-two plants were regenerated from 623 calli based on metabolic complementation. The morphological characters of the plants closely resembled that of the rice. Simple sequence repeats were employed to identify their hybridity. Cytological analysis of root-tips revealed that their chromosome number varied in the range of 27-38. The somatic hybrids were inoculated with strains of Xanthamonas oryzae pv. Oryzae at adult growth stage and demonstrated the resistance to bacterial blight introgression from the O. Meyeriana.

Copper-resistant bacteria enhance plant growth and copper phytoextraction.

Science.gov (United States)

Yang, Renxiu; Luo, Chunling; Chen, Yahua; Wang, Guiping; Xu, Yue; Shen, Zhenguo

2013-01-01

In this study, we investigated the role of rhizospheric bacteria in solubilizing soil copper (Cu) and promoting plant growth. The Cu-resistant bacterium DGS6 was isolated from a natural Cu-contaminated soil and was identified as Pseudomonas sp. DGS6. This isolate solubilized Cu in Cu-contaminated soil and stimulated root elongation of maize and sunflower. Maize was more sensitive to inoculation with DGS6 than was sunflower and exhibited greater root elongation. In pot experiment, inoculation with DGS6 increased the shoot dry weight of maize by 49% and sunflower by 34%, and increased the root dry weight of maize by 85% and sunflower by 45%. Although the concentrations of Cu in inoculated and non-inoculated seedlings did not differ significantly, the total accumulation of Cu in the plants increased after inoculation. DGS6 showed a high ability to solubilize P and produce iron-chelating siderophores, as well as significantly improved the accumulation of P and Fe in both maize and sunflower shoots. In addition, DGS6 produced indole-3-acetic acid (IAA) and ACC deaminase, which suggests that it may modulate ethylene levels in plants. The bacterial strain DGS6 could be a good candidate for re-vegetation of Cu-contaminated sites. Supplemental materials are available for this article. Go to the publisher's online edition of International Journal of Phytoremediation to view the supplemental file.

Effect of selected essential oil plants on bacterial wilt disease ...

African Journals Online (AJOL)

Objective: Bacterial wilt disease caused by Ralstonia solanacearum is a major constrain to production of potatoes (Solanum tuberosum). Control of bacterial wilt is very difficult as there are no effective curative chemicals. This study was aimed at investigating the potential roles of essential oil plants in control of the disease.

Characterization of N2-fixing plant growth promoting endophytic and epiphytic bacterial community of Indian cultivated and wild rice (Oryza spp.) genotypes.

Science.gov (United States)

Banik, Avishek; Mukhopadhaya, Subhra Kanti; Dangar, Tushar Kanti

2016-03-01

The diversity of endophytic and epiphytic diazotrophs in different parts of rice plants has specificity to the niche (i.e. leaf, stem and root) of different genotypes and nutrient availability of the organ. Inoculation of the indigenous, polyvalent diazotrophs can facilitate and sustain production of non-leguminous crops like rice. Therefore, N2-fixing plant growth promoting bacteria (PGPB) were isolated from different parts of three Indian cultivated [Oryza sativa L. var. Sabita (semi deep/deep water)/Swarna (rain fed shallow lowland)/Swarna-Sub1(submergence tolerant)] and a wild (O. eichingeri) rice genotypes which respond differentially to nitrogenous fertilizers. Thirty-five isolates from four rice genotypes were categorized based on acetylene reduction assay on nitrogenase activity, biochemical tests, BIOLOG and 16S rRNA gene sequencing. The bacteria produced 9.36-155.83 nmole C2H4 mg(-1) dry bacteria h(-1) and among them nitrogenase activity of 11 potent isolates was complemented by nifH-sequence analysis. Phylogenetic analysis based on 16S rDNA sequencing divided them into five groups (shared 95-100 % sequence homology with type strains) belonging to five classes-alpha (Ancylobacter, Azorhizobium, Azospirillum, Rhizobium, Bradyrhizobium, Sinorhizobium, Novosphingobium, spp.), beta (Burkholderia sp.), gamma (Acinetobacter, Aeromonas, Azotobacter, Enterobacter, Klebsiella, Pantoea, Pseudomonas, Stenotrophomonas spp.) Proteobacteria, Bacilli (Bacillus, Paenibacillus spp.) and Actinobacteria (Microbacterium sp.). Besides, all bacterial strains possessed the intrinsic PGP traits of like indole (0.44-7.4 µg ml(-1)), ammonia (0.18-6 mmol ml(-1)), nitrite (0.01-3.4 mol ml(-1)), and siderophore (from 0.16-0.57 μmol ml(-1)) production. Inoculation of rice (cv. Swarna) seedlings with selected isolates had a positive impact on plant growth parameters like shoot and root elongation which was correlated with in vitro PGP attributes. The results indicated that the

EFFECT OF MYCORRHIZAL INOCULANTS IN THE DEVELOPMENT OF MEXICAN LANDRACE AVOCADO ROOTSTOCKS

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Edgar Castro Alvarado

2013-12-01

Full Text Available The aim of this work was to assess the effect of two arbuscular mycorrhizal fungi (AMF inoculants in the development of avocado rootstocks. Seeds of Mexican landrace avocado (Persea americana Mill. var. drymifolia were used, with two commercial inoculants: T1 containing Glomus fasciculatum, G. constrictum, G. tortuosum, G. geosporum,and Acaulospora scrobiculata, and T2, containing G. mosseae and G. cubense.  The plants inoculated with AMF showed more rapid growth than the no inoculant control as measured by plant height (50% and 54%, stem diameter (35% and 36%, leaf number (48% and 37% and length (31% and 40%, and root fresh weight (85% and 59%; however, no significant differences were observed between T1 and T2. The chlorophyll concentration in the leaves from T1 was 16.4% and T2 was 19% higher than the control suggesting a higher photosynthetic capacity in T1 and T2. Finally the shoot/root ratio, as indicator of the potential development of plantations, was 79% and 50% higher in mycorrhizal plants than in the control. In conclusion both T1 and T2 inoculants improved growth rate and vigor of avocado nursery rootstocks producing higher quality plants.

Expression of alkane monooxygenase (alkB) genes by plant-associated bacteria in the rhizosphere and endosphere of Italian ryegrass (Lolium multiflorum L.) grown in diesel contaminated soil

International Nuclear Information System (INIS)

Andria, Verania; Reichenauer, Thomas G.; Sessitsch, Angela

2009-01-01

For phytoremediation of organic contaminants, plants have to host an efficiently degrading microflora. To assess the role of endophytes in alkane degradation, Italian ryegrass was grown in sterile soil with 0, 1 or 2% diesel and inoculated either with an alkane degrading bacterial strain originally derived from the rhizosphere of Italian ryegrass or with an endophyte. We studied plant colonization of these strains as well as the abundance and expression of alkane monooxygenase (alkB) genes in the rhizosphere, shoot and root interior. Results showed that the endophyte strain better colonized the plant, particularly the plant interior, and also showed higher expression of alkB genes suggesting a more efficient degradation of the pollutant. Furthermore, plants inoculated with the endophyte were better able to grow in the presence of diesel. The rhizosphere strain colonized primarily the rhizosphere and showed low alkB gene expression in the plant interior. - Bacterial alkane degradation genes are expressed in the rhizosphere and in the plant interior.

Expression of alkane monooxygenase (alkB) genes by plant-associated bacteria in the rhizosphere and endosphere of Italian ryegrass (Lolium multiflorum L.) grown in diesel contaminated soil

Energy Technology Data Exchange (ETDEWEB)

Andria, Verania [AIT Austrian Institute of Technology GmbH, Bioresources Unit, A-2444 Seibersdorf (Austria); Reichenauer, Thomas G. [AIT Austrian Institute of Technology GmbH, Unit of Environmental Resources and Technologies, A-2444 Seibersdorf (Austria); Sessitsch, Angela, E-mail: angela.sessitsch@ait.ac.a [AIT Austrian Institute of Technology GmbH, Bioresources Unit, A-2444 Seibersdorf (Austria)

2009-12-15

For phytoremediation of organic contaminants, plants have to host an efficiently degrading microflora. To assess the role of endophytes in alkane degradation, Italian ryegrass was grown in sterile soil with 0, 1 or 2% diesel and inoculated either with an alkane degrading bacterial strain originally derived from the rhizosphere of Italian ryegrass or with an endophyte. We studied plant colonization of these strains as well as the abundance and expression of alkane monooxygenase (alkB) genes in the rhizosphere, shoot and root interior. Results showed that the endophyte strain better colonized the plant, particularly the plant interior, and also showed higher expression of alkB genes suggesting a more efficient degradation of the pollutant. Furthermore, plants inoculated with the endophyte were better able to grow in the presence of diesel. The rhizosphere strain colonized primarily the rhizosphere and showed low alkB gene expression in the plant interior. - Bacterial alkane degradation genes are expressed in the rhizosphere and in the plant interior.

Plant growth-promoting endophytic bacteria versus pathogenic infections: an example of Bacillus amyloliquefaciens RWL-1 and Fusarium oxysporum f. sp. lycopersici in tomato

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Raheem Shahzad

2017-03-01

Full Text Available Fungal pathogenic attacks are one of the major threats to the growth and productivity of crop plants. Currently, instead of synthetic fungicides, the use of plant growth-promoting bacterial endophytes has been considered intriguingly eco-friendly in nature. Here, we aimed to investigate the in vitro and in vivo antagonistic approach by using seed-borne endophytic Bacillus amyloliquefaciens RWL-1 against pathogenic Fusarium oxysporum f. sp. lycopersici. The results revealed significant suppression of pathogenic fungal growth by Bacillus amyloliquefaciens in vitro. Further to this, we inoculated tomato plants with RWL-1 and F. oxysporum f. sp. lycopersici in the root zone. The results showed that the growth attributes and biomass were significantly enhanced by endophytic-inoculation during disease incidence as compared to F. oxysporum f. sp. lycopersici infected plants. Under pathogenic infection, the RWL-1-applied plants showed increased amino acid metabolism of cell wall related (e.g., aspartic acid, glutamic acid, serine (Ser, and proline (Pro as compared to diseased plants. In case of endogenous phytohormones, significantly lower amount of jasmonic acid (JA and higher amount of salicylic acid (SA contents was recorded in RWL-1-treated diseased plants. The phytohormones regulation in disease incidences might be correlated with the ability of RWL-1 to produce organic acids (e.g., succinic acid, acetic acid, propionic acid, and citric acid during the inoculation and infection of tomato plants. The current findings suggest that RWL-1 inoculation promoted and rescued plant growth by modulating defense hormones and regulating amino acids. This suggests that bacterial endophytes could be used for possible control of F. oxysporum f. sp. lycopersici in an eco-friendly way.

Bacterial selection for biological control of plant disease: criterion determination and validation

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Monalize Salete Mota

Full Text Available Abstract This study aimed to evaluate the biocontrol potential of bacteria isolated from different plant species and soils. The production of compounds related to phytopathogen biocontrol and/or promotion of plant growth in bacterial isolates was evaluated by measuring the production of antimicrobial compounds (ammonia and antibiosis and hydrolytic enzymes (amylases, lipases, proteases, and chitinases and phosphate solubilization. Of the 1219 bacterial isolates, 92% produced one or more of the eight compounds evaluated, but only 1% of the isolates produced all the compounds. Proteolytic activity was most frequently observed among the bacterial isolates. Among the compounds which often determine the success of biocontrol, 43% produced compounds which inhibit mycelial growth of Monilinia fructicola, but only 11% hydrolyzed chitin. Bacteria from different plant species (rhizosphere or phylloplane exhibited differences in the ability to produce the compounds evaluated. Most bacterial isolates with biocontrol potential were isolated from rhizospheric soil. The most efficient bacteria (producing at least five compounds related to phytopathogen biocontrol and/or plant growth, 86 in total, were evaluated for their biocontrol potential by observing their ability to kill juvenile Mesocriconema xenoplax. Thus, we clearly observed that bacteria that produced more compounds related to phytopathogen biocontrol and/or plant growth had a higher efficacy for nematode biocontrol, which validated the selection strategy used.

Plant growth promoting capability and genetic diversity of bacteria isolated from mud volcano and lime cave of Andaman and Nicobar Islands.

Science.gov (United States)

Venkadesaperumal, Gopu; Amaresan, Natrajan; Kumar, Krishna

2014-01-01

Twenty four bacterial strains from four different regions of mud volcano and lime cave were isolated to estimate their diversity, plant growth promoting and biocontrol activities to use them as inoculant strains in the fields. An excellent antagonistic effect against four plant pathogens and plant growth promoting properties such as IAA production, HCN production, phosphate solubilization, siderophore production, starch hydrolysis and hydrolytic enzymes syntheses were identified in OM5 (Pantoea agglomerans) and EM9 (Exiguobacterium sp.) of 24 studied isolates. Seeds (Chili and tomato) inoculation with plant growth promoting strains resulted in increased percentage of seedling emergence, root length and plant weight. Results indicated that co-inoculation gave a more pronounced effects on seedling emergence, secondary root numbers, primary root length and stem length, while inoculation by alone isolate showed a lower effect. Our results suggest that the mixed inocula of OM5 and EM9 strains as biofertilizers could significantly increase the production of food crops in Andaman archipelago by means of sustainable and organic agricultural system.

Plant growth promoting capability and genetic diversity of bacteria isolated from mud volcano and lime cave of Andaman and Nicobar Islands

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Gopu Venkadesaperumal

2014-12-01

Full Text Available Twenty four bacterial strains from four different regions of mud volcano and lime cave were isolated to estimate their diversity, plant growth promoting and biocontrol activities to use them as inoculant strains in the fields. An excellent antagonistic effect against four plant pathogens and plant growth promoting properties such as IAA production, HCN production, phosphate solubilization, siderophore production, starch hydrolysis and hydrolytic enzymes syntheses were identified in OM5 (Pantoea agglomerans and EM9 (Exiguobacterium sp. of 24 studied isolates. Seeds (Chili and tomato inoculation with plant growth promoting strains resulted in increased percentage of seedling emergence, root length and plant weight. Results indicated that co-inoculation gave a more pronounced effects on seedling emergence, secondary root numbers, primary root length and stem length, while inoculation by alone isolate showed a lower effect. Our results suggest that the mixed inocula of OM5 and EM9 strains as biofertilizers could significantly increase the production of food crops in Andaman archipelago by means of sustainable and organic agricultural system.

Real time expression of ACC oxidase and PR-protein genes mediated by Methylobacterium spp. in tomato plants challenged with Xanthomonas campestris pv. vesicatoria.

Science.gov (United States)

Yim, W J; Kim, K Y; Lee, Y W; Sundaram, S P; Lee, Y; Sa, T M

2014-07-15

Biotic stress like pathogenic infection increases ethylene biosynthesis in plants and ethylene inhibitors are known to alleviate the severity of plant disease incidence. This study aimed to reduce the bacterial spot disease incidence in tomato plants caused by Xanthomonas campestris pv. vesicatoria (XCV) by modulating stress ethylene with 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity of Methylobacterium strains. Under greenhouse condition, Methylobacterium strains inoculated and pathogen challenged tomato plants had low ethylene emission compared to pathogen infected ones. ACC accumulation and ACC oxidase (ACO) activity with ACO related gene expression increased in XCV infected tomato plants over Methylobacterium strains inoculated plants. Among the Methylobacterium spp., CBMB12 resulted lowest ACO related gene expression (1.46 Normalized Fold Expression), whereas CBMB20 had high gene expression (3.42 Normalized Fold Expression) in pathogen challenged tomato. But a significant increase in ACO gene expression (7.09 Normalized Fold Expression) was observed in the bacterial pathogen infected plants. In contrast, Methylobacterium strains enhanced β-1,3-glucanase and phenylalanine ammonia-lyase (PAL) enzyme activities in pathogen challenged tomato plants. The respective increase in β-1,3-glucanase related gene expressions due to CBMB12, CBMB15, and CBMB20 strains were 66.3, 25.5 and 10.4% higher over pathogen infected plants. Similarly, PAL gene expression was high with 0.67 and 0.30 Normalized Fold Expression, in pathogen challenged tomato plants inoculated with CBMB12 and CBMB15 strains. The results suggest that ethylene is a crucial factor in bacterial spot disease incidence and that methylobacteria with ACC deaminase activity can reduce the disease severity with ultimate pathogenesis-related protein increase in tomato. Copyright © 2014 Elsevier GmbH. All rights reserved.

Metabolic response induced by endophytic fungi and bacteria in H. marrubioides Epling in vitro micro plants

Energy Technology Data Exchange (ETDEWEB)

Vitorino, Luciana Cristina; Silva, Fabiano Guimaraes, E-mail: fabianocefetrv@yahoo.com.br [Instituto Federal de Educacao, Ciencia e Tecnologia Goiano, Rio Verde, GO (Brazil); Lima, William Cardoso; Soares, Marcos Antonio [Universidade Federal de Mato Grosso (UFMT), Cuiaba, MT (Brazil). Dept. de Botanica e Ecologia; Pedroso, Rita Cassia Nascimento; Silva, Maroli Rodrigues; Dias, Herbert Junior; Crotti, Antonio Eduardo Miller; Silva, Marcio Luis Andrade e; Cunha, Wilson Roberto; Pauletti, Patricia Mendonca; Januario, Ana Helena [Universidade de Franca, SP (Brazil). Nucleo de Pesquisa em Ciencias Exatas e Tecnologicas

2013-10-01

Hyptis marrubioides Epling is a native plant from Brazilian Cerrado. In this paper, the response of in vitro micro plants of this species to inoculation with bacterial and fungal endophytic isolates is evaluated. HPLC-DAD analysis showed the presence of 3,4-O-(Z)-dicaffeoylquinic acid and quercetin-7-O-glucoside as the main components. GC/MS analysis demonstrated that the sesquiterpenes Greek-Small-Letter-Tau -cadinol and caryophyllene oxide were only produced in micro plants inoculated with endophytic bacteria, while methyl hexadecanoate, methyl heptadecanoate and methyl (Z,Z,Z) 9,12,15-octadecatrienoate and the triterpene methyl 3{beta}-hydroxy-urs-12-en-28-oate were over expressed only when the micro plant was treated with endophytic fungi. (author)

A Community-Based Culture Collection for Targeting Novel Plant Growth-Promoting Bacteria from the Sugarcane Microbiome

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Jaderson Silveira Leite Armanhi

2018-01-01

Full Text Available The soil-plant ecosystem harbors an immense microbial diversity that challenges investigative approaches to study traits underlying plant-microbe association. Studies solely based on culture-dependent techniques have overlooked most microbial diversity. Here we describe the concomitant use of culture-dependent and -independent techniques to target plant-beneficial microbial groups from the sugarcane microbiome. The community-based culture collection (CBC approach was used to access microbes from roots and stalks. The CBC recovered 399 unique bacteria representing 15.9% of the rhizosphere core microbiome and 61.6–65.3% of the endophytic core microbiomes of stalks. By cross-referencing the CBC (culture-dependent with the sugarcane microbiome profile (culture-independent, we designed a synthetic community comprised of naturally occurring highly abundant bacterial groups from roots and stalks, most of which has been poorly explored so far. We then used maize as a model to probe the abundance-based synthetic inoculant. We show that when inoculated in maize plants, members of the synthetic community efficiently colonize plant organs, displace the natural microbiota and dominate at 53.9% of the rhizosphere microbial abundance. As a result, inoculated plants increased biomass by 3.4-fold as compared to uninoculated plants. The results demonstrate that abundance-based synthetic inoculants can be successfully applied to recover beneficial plant microbes from plant microbiota.

Colonization of Tomato Root by Antagonistic Bacterial Strains to Fusarium Wilt of Tomato

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Arif Wibowo

2005-12-01

Full Text Available Fusarium wilt of tomato caused by Fusarium oxysporum f.sp. lycopersici (Fol is an important disease in tomato which cause a significant loss of yield in major growing regions of the world. This study examined the ability of bacterial strains antagonistic to F. oxysporum f.sp. lycopersici (H5, H22, H63, H71, Burkholderia cepacia strain 65 and 526 to colonize tomato seedlings and the effect of plant growth. The effect of bacterial population size and air temperature on the bacterial colonization and their spread along the root systems was also assessed.The results of this study showed that the bacterial population at 28°/23° C day/night temperature 14 days after planting was significantly greater than 23°/18° C for 4 of 6 strains tested. Although there was no significant effect of temperature on bacterial population observed in this study, the ability of the baacterial strains to colonize the rhizosphere was significantly different. Three strains (H5, B. cepacia strain 65 and 526 survived well in the rhizosphere and at 4 weeks after planting rhizosphere populations per gram fresh root were not significantly different from those recovered 2 weeks after planting. The largest population of the bacterial inoculants developed in the basal region of the roots and this differed between strains by log10 2.7 cfu/cm root. The bacterial populations in other parts of the root were also strain dependent. Strain H71, for example, was able to colonize the root segments at a high population level. However strain H63 was recovered only in small number in all root segments.

Properties of bacterial endophytes and their proposed role in plant growth

NARCIS (Netherlands)

Hardoim, P.R.; Overbeek, van L.S.; Elsas, van J.D.

2008-01-01

Bacterial endophytes live inside plants for at least part of their life cycle. Studies of the interaction of endophytes with their host plants and their function within their hosts are important to address the ecological relevance of endophytes. The modulation of ethylene levels in plants by

Beauveria bassiana and Metarhizium anisopliae endophytically colonize cassava roots following soil drench inoculation

Science.gov (United States)

Greenfield, Melinda; Gómez-Jiménez, María I.; Ortiz, Viviana; Vega, Fernando E.; Kramer, Matthew; Parsa, Soroush

2016-01-01

We investigated the fungal entomopathogens Beauveria bassiana and Metarhizium anisopliae to determine if endophytic colonization could be achieved in cassava. An inoculation method based on drenching the soil around cassava stem cuttings using conidial suspensions resulted in endophytic colonization of cassava roots by both entomopathogens, though neither was found in the leaves or stems of the treated cassava plants. Both fungal entomopathogens were detected more often in the proximal end of the root than in the distal end. Colonization levels of B. bassiana were higher when plants were sampled at 7–9 days post-inoculation (84%) compared to 47–49 days post-inoculation (40%). In contrast, the colonization levels of M. anisopliae remained constant from 7–9 days post-inoculation (80%) to 47–49 days post-inoculation (80%), which suggests M. anisopliae is better able to persist in the soil, or as an endophyte in cassava roots over time. Differences in colonization success and plant growth were found among the fungal entomopathogen treatments. PMID:27103778

Effect of adding sour yoghurt and dough as bacterial inoculant on ...

African Journals Online (AJOL)

Inoculation of whole-crop corn with sourdough and sour yoghurt significantly decreased pH, ash content and ammonia nitrogen, while dry matter determined using toloen distillation (DMT), Flieg point, crude protein (CP), and total nitrogen increased (P<0.05). Key words: Silage, sour yoghurt, sourdough, corn forage.

Inoculation of Brassica oxyrrhina with plant growth promoting bacteria for the improvement of heavy metal phytoremediation under drought conditions.

Science.gov (United States)

Ma, Ying; Rajkumar, Mani; Zhang, Chang; Freitas, Helena

2016-12-15

The aim of this study was to investigate the effects of drought resistant serpentine rhizobacteria on plant growth and metal uptake by Brassica oxyrrhina under drought stress (DS) condition. Two drought resistant serpentine rhizobacterial strains namely Pseudomonas libanensis TR1 and Pseudomonas reactans Ph3R3 were selected based on their ability to stimulate seedling growth in roll towel assay. Further assessment on plant growth promoting (PGP) parameters revealed their ability to produce indole-3-acetic acid, siderophore and 1-aminocyclopropane-1-carboxylate deaminase. Moreover, both strains exhibited high resistance to various heavy metals, antibiotics, salinity and extreme temperature. Inoculation of TR1 and Ph3R3 significantly increased plant growth, leaf relative water and pigment content of B. oxyrrhina, whereas decreased concentrations of proline and malondialdehyde in leaves under metal stress in the absence and presence of DS. Regardless of soil water conditions, TR1 and Ph3R3 greatly improved organ metal concentrations, translocation and bioconcentration factors of Cu and Zn. The successful colonization and metabolic activities of P. libanensis TR1 and P. reactans Ph3R3 represented positive effects on plant development and metal phytoremediation under DS. These results indicate that these strains could be used as bio-inoculants for the improvement of phytoremediation of metal polluted soils under semiarid conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Rhizostabilization of metals in soils using Lupinus luteus inoculated with the metal resistant rhizobacterium Serratia sp. MSMC541.

Science.gov (United States)

El Aafi, N; Brhada, F; Dary, M; Maltouf, A Filali; Pajuelo, E

2012-03-01

The aim of this work was to test Lupinus luteus plants, inoculated with metal resistant rhizobacteria, in order to phytostabilise metals in contaminated soils. The resistance to heavy metals of strains isolated from nodules of Lupinus plants was evaluated. The strain MSMC541 showed multi-resistance to several metals (up to 13.3 mM As, 2.2 mM Cd, 2.3 mM Cu, 9 mM Pb and 30 mM Zn), and it was selected for further characterization. Furthermore, this strain was able to biosorb great amounts of metals in cell biomass. 16S rDNA sequencing positioned this strain within the genus Serratia. The presence of arsenic resistance genes was confirmed by southern blot and PCR amplification. A rhizoremediation pot experiment was conducted using Lupinus luteus grown on sand supplemented with heavy metals and inoculated with MSMC541. Plant growth parameters and metal accumulation were determined in inoculated vs. non-inoculated Lupinus luteus plants. The results showed that inoculation with MSMC541 improved the plant tolerance to metals. At the same time, metal translocation to the shoot was significantly reduced upon inoculation. These results suggest that Lupinus luteus plants, inoculated with the metal resistant strain Serratia sp. MSMC541, have a great potential for phytostabilization of metal contaminated soils.

Effects of the plant growth-promoting bacterium Burkholderia phytofirmans PsJN throughout the life cycle of Arabidopsis thaliana.

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María Josefina Poupin

Full Text Available Plant growth-promoting rhizobacteria (PGPR induce positive effects in plants, such as increased growth or reduced stress susceptibility. The mechanisms behind PGPR/plant interaction are poorly understood, as most studies have described short-term responses on plants and only a few studies have analyzed plant molecular responses under PGPR colonization. Here, we studied the effects of the PGPR bacterial model Burkholderiaphytofirmans PsJN on the whole life cycle of Arabidopsis thaliana plants. We reported that at different plant developmental points, strain PsJN can be found in the rhizosphere and also colonizing their internal tissues. In early ontogeny, strain PsJN increased several growth parameters and accelerated growth rate of the plants. Also, an Arabidopsis transcriptome analysis revealed that 408 genes showed differential expression in PsJN-inoculated plants; some of these genes are involved in stress response and hormone pathways. Specifically, genes implicated in auxin and gibberellin pathways were induced. Quantitative transcriptional analyses of selected genes in different developmental stages revealed that the beginning of these changes could be evidenced early in development, especially among the down-regulated genes. The inoculation with heat-killed bacteria provoked a more severe transcriptional response in plants, but was not able to induce plant growth-promotion. Later in ontogeny, the growth rates of inoculated plants decreased with respect to the non-inoculated group and, interestingly, the inoculation accelerated the flowering time and the appearance of senescence signs in plants; these modifications correlate with the early up-regulation of flowering control genes. Then, we show that a single inoculation with a PGPR could affect the whole life cycle of a plant, accelerating its growth rate and shortening its vegetative period, both effects relevant for most crops. Thus, these findings provide novel and interesting aspects

The effect of selected plant extracts on the development of single-species dental biofilms

International Nuclear Information System (INIS)

Rahim, Z.H.; Shaikh, S.; Razak, A.; Ismail, W.N.H.W.

2014-01-01

To determine the effect of a mixture of plant extracts on the adherence and retention of bacteria in dental biofilm. Study Design: Experimental study. Place and Duration of Study:Department of Oral Biology, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia, from December 2009 to December 2011. Methodology: For determination of adhering ability, experimental pellicle was first treated with the Plant Extracts Mixture (PEM) before inoculating it with individual bacterial species ( S. mitis / S. sanguinis / S. mutans). For the determination of retention ability, the procedure was repeated with the experimental pellicle being inoculated first with the individual bacterial species and then treating it with the PEM. These two experiments were repeated with deionized distilled water (negative control) and Thymol (0.64%) (positive control). The bacterial populations in biofilms for the two experiments were expressed as Colony Forming Unit (CFU) / mL x 10/sup 4/ and the corresponding values were expressed as mean +- SD. Results: The effect of the Plant Extracts Mixture (PEM) for the two experiments was compared with that of Thymol and deionized distilled water. It was shown that there is a reduced adherence of bacteria to PEM-treated and Thymol (0.064%) treated experimental pellicle compared with the negative control (p < 0.001). It was also found that the retention of bacteria in both treated biofilms is also lower than that of negative control (p = 0.001). Conclusion: Plant Extracts Mixture (PEM) may influence the development of dental biofilm by affecting the adhering and retention capacities of the bacterial species in the dental biofilms. (author)

Persistence of Two Campylobacter jejuni Strains in Soil and on Spinach Plants

International Nuclear Information System (INIS)

Jaderlund, L.; Arthurson, V.; Sessitsch, A.

2011-01-01

There are indications that the more frequent use of untreated organic residues for fertilization results in increased risk of contamination with human pathogens. Here, we evaluate the ability of two different strains of Campylobacter jejuni to persist in manure and soil as well as spread to spinach plants. It was revealed that different strategies for inoculation of C. jejuni contribute to the persistence of the bacterium in soil, roots, and shoots. Upon inoculation of the bacteria into manure prior to soil application, the amount of C. jejuni subsequently recovered in soil was higher than that from treatments involving the addition of C. jejuni cells to the soil after plant emergence. Irrespective of the bacterial inoculation dose and strategy employed, the C. jejuni content in soil remained relatively constant, whereas the majority of C. jejuni cells applied to spinach leaves could be recovered during the whole evaluation period of 21 days.

Growth and {sup 137}Cs uptake of four Brassica species influenced by inoculation with a plant growth-promoting rhizobacterium Bacillus pumilus in three contaminated farmlands in Fukushima prefecture, Japan

Energy Technology Data Exchange (ETDEWEB)

Aung, Han Phyo [United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509 (Japan); Djedidi, Salem; Oo, Aung Zaw [Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509 (Japan); Aye, Yi Swe [Department of International Environmental and Agricultural Science, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509 (Japan); Yokoyama, Tadashi; Suzuki, Sohzoh [Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509 (Japan); Sekimoto, Hitoshi [Faculty of Agriculture, Utsunomiya University, 321-8505 (Japan); Bellingrath-Kimura, Sonoko Dorothea, E-mail: skimura@cc.tuat.ac.jp [Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509 (Japan)

2015-07-15

The effectiveness of the plant growth-promoting rhizobacterium Bacillus pumilus regarding growth promotion and radiocesium ({sup 137}Cs) uptake was evaluated in four Brassica species grown on different {sup 137}Cs contaminated farmlands at Fukushima prefecture in Japan from June to August 2012. B. pumilus inoculation did not enhance growth in any of the plants, although it resulted in a significant increase of {sup 137}Cs concentration and higher {sup 137}Cs transfer from the soil to plants. The Brassica species exhibited different {sup 137}Cs uptake abilities in the order Komatsuna > turnip > mustard > radish. TF values of {sup 137}Cs ranged from 0.018 to 0.069 for all vegetables. Komatsuna possessed the largest root surface area and root volume, and showed a higher {sup 137}Cs concentration in plant tissue and higher {sup 137}Cs TF values (0.060) than the other vegetables. Higher {sup 137}Cs transfer to plants was prominent in soil with a high amount of organic matter and an Al-vermiculite clay mineral type. - Highlights: • PGPR inoculation did not enhance plant biomass of tested plants. • PGPR inoculation resulted in higher {sup 137}Cs concentration in plants. • Komatsuna that had larger root volume showed higher {sup 137}Cs TF from soil to plants. • Soil with high SOM and Al-vermiculite caused larger {sup 137}Cs transfer to plants.

Arbuscular mycorrhizal fungus inoculation reduces the drought-resistance advantage of endophyte-infected versus endophyte-free Leymus chinensis.

Science.gov (United States)

Liu, Hui; Chen, Wei; Wu, Man; Wu, Rihan; Zhou, Yong; Gao, Yubao; Ren, Anzhi

2017-11-01

Grasses can be infected simultaneously by endophytic fungi and arbuscular mycorrhizal (AM) fungi. In this study, we tested the hypothesis that endophyte-associated drought resistance of a native grass was affected by an AM fungus. In a greenhouse experiment, we compared the performance of endophyte-infected (EI) and endophyte-free (EF) Leymus chinensis, a dominant species native to the Inner Mongolia steppe, under altered water and AM fungus availability. The results showed that endophyte infection significantly increased drought resistance of the host grass, but the beneficial effects were reduced by AM fungus inoculation. In the mycorrhizal-non-inoculated (MF) treatment, EI plants accumulated significantly more biomass, had greater proline and total phenolic concentration, and lower malondialdehyde concentration than EF plants. In the mycorrhizal-inoculation (MI) treatment, however, no significant difference occurred in either growth or physiological characters measured between EI and EF plants. AM fungus inoculation enhanced drought resistance of EF plants but had no significant effect on drought resistance of EI plants, thus AM fungus inoculation reduced the difference between EI and EF plants. Our findings highlight the importance of interactions among multiple microorganisms for plant performance under drought stress.

Prospective bacterial quorum sensing inhibitors from Indian medicinal plant extracts.

Science.gov (United States)

Tiwary, B K; Ghosh, R; Moktan, S; Ranjan, V K; Dey, P; Choudhury, D; Dutta, S; Deb, D; Das, A P; Chakraborty, R

2017-07-01

As virulence of many pathogenic bacteria is regulated by the phenomenon of quorum sensing (QS), the present study aimed to find the QS-inhibiting (QS-I) property (if any) in 61 Indian medicinal plants. The presence of QS-I compound in the leaf extract was evaluated by its ability to inhibit production of pigment in Chromobacterium violaceum MTCC 2656 (violacein) and Pseudomonas aeruginosa MTCC 2297 (pyocyanin) or swarming of P. aeruginosa MTCC 2297. Extracts of three plants, Astilbe rivularis, Fragaria nubicola and Osbeckia nepalensis, have shown a dose-dependent inhibition of violacein production with no negative effect on bacterial growth. Inhibition of pyocyanin pigment production and swarming motility in P. aeruginosa MTCC 2297 was also shown. Based on the results obtained by gas chromatography-mass spectroscopy (GC-MS) and thin-layer chromatography-direct bioautography (TLC-DB), it was concluded that triterpenes and flavonoid compounds found in the three plant extracts could have QS-I activity. A novel alternative prospect to prevent bacterial infections without inhibiting the growth is to apply chemicals that inhibit quorum sensing mechanism of the pathogens. Antiquorum property of 61 medicinal plants was evaluated by the ability of their leaf extract(s) to inhibit production of pigment (violacein in Chromobacterium violaceum MTCC 2656, pyocyanin in Pseudomonas aeruginosa MTCC 2297) or swarming in P. aeruginosa MTCC 2297. The most prospective plants (for the development of quorum sensing inhibitor), showing inhibition of violacein production without affecting bacterial growth, were Astilbe rivularis, Fragaria nubicola and Osbeckia nepalensis. © 2017 The Society for Applied Microbiology.

Unraveling plant responses to bacterial pathogens through proteomics

KAUST Repository

Zimaro, Tamara; Gottig, Natalia; Garavaglia, Betiana S.; Gehring, Christoph A; Ottado, Jorgelina

2011-01-01

Plant pathogenic bacteria cause diseases in important crops and seriously and negatively impact agricultural production. Therefore, an understanding of the mechanisms by which plants resist bacterial infection at the stage of the basal immune response or mount a successful specific R-dependent defense response is crucial since a better understanding of the biochemical and cellular mechanisms underlying these interactions will enable molecular and transgenic approaches to crops with increased biotic resistance. In recent years, proteomics has been used to gain in-depth understanding of many aspects of the host defense against pathogens and has allowed monitoring differences in abundance of proteins as well as posttranscriptional and posttranslational processes, protein activation/inactivation, and turnover. Proteomics also offers a window to study protein trafficking and routes of communication between organelles. Here, we summarize and discuss current progress in proteomics of the basal and specific host defense responses elicited by bacterial pathogens. Copyright 2011 Tamara Zimaro et al.

Unraveling plant responses to bacterial pathogens through proteomics

KAUST Repository

Zimaro, Tamara

2011-11-03

Plant pathogenic bacteria cause diseases in important crops and seriously and negatively impact agricultural production. Therefore, an understanding of the mechanisms by which plants resist bacterial infection at the stage of the basal immune response or mount a successful specific R-dependent defense response is crucial since a better understanding of the biochemical and cellular mechanisms underlying these interactions will enable molecular and transgenic approaches to crops with increased biotic resistance. In recent years, proteomics has been used to gain in-depth understanding of many aspects of the host defense against pathogens and has allowed monitoring differences in abundance of proteins as well as posttranscriptional and posttranslational processes, protein activation/inactivation, and turnover. Proteomics also offers a window to study protein trafficking and routes of communication between organelles. Here, we summarize and discuss current progress in proteomics of the basal and specific host defense responses elicited by bacterial pathogens. Copyright 2011 Tamara Zimaro et al.

The utilization of microbial inoculants based on irradiated compost in dryland remediation to increase the growth of king grass and maize

International Nuclear Information System (INIS)

TRD Larasati; N Mulyana; D Sudradjat

2016-01-01

This research was conducted to evaluate the capability of functional microbial inoculants to remediate drylands. The microbial inoculants used consist of hydrocarbon-degrading microbial inoculants and plant-growth-promoting microbial inoculants. Compost-based carrier was sterilized by a gamma irradiation dose of 25 kGy to prepare seed inoculants. The irradiated-compost-based hydrocarbon-degrading microbial inoculants and king grass (Pennisetum purpureum Schumach.) were used to remediate oil-sludge-contaminated soil using in-situ composting for 60 days. The results showed that they could reduce THP (total petroleum hydrocarbons) by up to 82.23%. Plant-growth-promoting microbial inoculants were able to increase the dry weight of king grass from 47.39 to 100.66 g/plant, N uptake from 415.53 to 913.67 mg/plant, and P uptake from 76.52 to 178.33 mg/plant. Cow dung and irradiated-compost-based plant-growth-promoting microbial inoculants were able to increase the dry weight of maize (Zea mays L.) from 5.75 to 6.63 ton/ha (12.54%) and dry weight of grain potential from 5.30 to 7.15 ton/ha (35.03%). The results indicate that irradiated-compost-based microbial inoculants are suitable for remediating a dryland and therefore increase potential resources and improve the quality of the environment. (author)

Differential activity of autochthonous bacteria in controlling drought stress in native Lavandula and Salvia plants species under drought conditions in natural arid soil.

Science.gov (United States)

Armada, Elisabeth; Roldán, Antonio; Azcon, Rosario

2014-02-01

The effectiveness of autochthonous plant growth-promoting rhizobacteria was studied in Lavandula dentata and Salvia officinalis growing in a natural arid Mediterranean soil under drought conditions. These bacteria identified as Bacillus megaterium (Bm), Enterobacter sp. (E), Bacillus thuringiensis (Bt), and Bacillus sp. (Bsp). Each bacteria has different potential to meliorate water limitation and alleviating drought stress in these two plant species. B. thuringiensis promoted growth and drought avoidance in Lavandula by increasing K content, by depressing stomatal conductance, and it controlled shoot proline accumulation. This bacterial effect on increasing drought tolerance was related to the decrease of glutathione reductase (GR) and ascorbate peroxidase (APX) that resulted sensitive indexes of lower cellular oxidative damage involved in the adaptative drought response in B. thuringiensis-inoculated Lavandula plants. In contrast, in Salvia, having intrinsic lower shoot/root ratio, higher stomatal conductance and lower APX and GR activities than Lavandula, the bacterial effects on nutritional, physiological and antioxidant enzymatic systems were lower. The benefit of bacteria depended on intrinsic stress tolerance of plant involved. Lavadula demonstrated a greater benefit than Salvia to control drought stress when inoculated with B. thuringiensis. The bacterial drought tolerance assessed as survival, proline, and indolacetic acid production showed the potential of this bacteria to help plants to grow under drought conditions. B. thuringiensis may be used for Lavandula plant establishment in arid environments. Particular characteristic of the plant species as low shoot/root ratio and high stomatal conductance are important factors controlling the bacterial effectiveness improving nutritional, physiological, and metabolic plant activities.

Inoculation of the nonlegume Capsicum annuum (L.) with Rhizobium strains. 1. Effect on bioactive compounds, antioxidant activity, and fruit ripeness.

Science.gov (United States)

Silva, Luís R; Azevedo, Jessica; Pereira, Maria J; Carro, Lorena; Velazquez, Encarna; Peix, Alvaro; Valentão, Patrícia; Andrade, Paula B

2014-01-22

Pepper (Capsicum annuum L.) is an economically important agricultural crop and an excellent dietary source of natural colors and antioxidant compounds. The levels of these compounds can vary according to agricultural practices, like inoculation with plant growth-promoting rhizobacteria. In this work we evaluated for the first time the effect of the inoculation of two Rhizobium strains on C. annuum metabolites and bioactivity. The results revealed a decrease of organic acids and no effect on phenolics and capsaicinoids of leaves from inoculated plants. In the fruits from inoculated plants organic acids and phenolic compounds decreased, showing that fruits from inoculated plants present a higher ripeness stage than those from uninoculated ones. In general, the inoculation with Rhizobium did not improve the antioxidant activity of pepper fruits and leaves. Considering the positive effect on fruit ripening, the inoculation of C. annuum with Rhizobium is a beneficious agricultural practice for this nonlegume.

Real-time PCR quantification of the plant growth promoting bacteria Herbaspirillum seropedicae strain SmR1 in maize roots.

Science.gov (United States)

Pereira, Tomás Pellizzaro; do Amaral, Fernanda Plucani; Dall'Asta, Pamela; Brod, Fábio Cristiano Angonesi; Arisi, Ana Carolina Maisonnave

2014-07-01

The plant growth promoting bacteria Herbaspirillum seropedicae SmR1 is an endophytic diazotroph found in several economically important crops. Considering that methods to monitor the plant-bacteria interaction are required, our objective was to develop a real-time PCR method for quantification of PGPB H. seropedicae in the rhizosphere of maize seedlings. Primer pairs were designed, and their specificity was verified using DNA from 12 different bacterial species. Ten standard curves of qPCR assay using HERBAS1 primers and tenfold serial dilutions of H. seropedicae SmR1 DNA were performed, and PCR efficiency of 91 % and correlation coefficient of 0.99 were obtained. H. seropedicae SmR1 limit of detection was 10(1) copies (corresponding to 60.3 fg of bacterial DNA). qPCR assay using HERBAS1 was used to detect and quantify H. seropedicae strain SmR1 in inoculated maize roots, cultivated in vitro and in pots, harvested 1, 4, 7, and 10 days after inoculation. The estimated bacterial DNA copy number per gram of root was in the range 10(7)-10(9) for plants grown in vitro and it was around 10(6) for plants grown in pots. Primer pair HERBAS1 was able to quantify H. seropedicae SmR1, and this assay can be useful for monitoring plant-bacteria interaction.

Quantitative Simulation of Damage Roots on Inoculated Alfalfa by Arbuscular Mycorrhiza Fungi

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Ying Liu

2017-12-01

Full Text Available Underground mining would cause ground subsidence damage and large amounts of cracks, which would result a loss of surface moisture and nutrient and intensifying drought. There are a few reports about damage to plant roots caused by coal mining. The irregular distribution of plant roots in soil and the different forces generated in process of surface subsidence are difficult to study comprehensively. The technologies to repair damaged plant roots have not been completely perfected yet. Based on quantitative simulation of alfalfa root cut-repair experiment, this paper discusses the influences of inoculated Arbuscular Mycorrhiza Fungi on alfalfa root and the mitigation effects of an inoculation on the growth of alfalfa. Root injured alfalfa were investigated by soil pot experiments. The result indicated that at the same cut degree, the growth situation of inoculated alfalfa is better than the contrast. Compared with the Olsen-P content, at cut level of 0 and 1/3, the sand of inoculated alfalfa has less Olsen-P than contrast, at cut degree of 1/2 and 2/3, the sand of inoculated alfalfa has more Olsen-P than contrast, at degree of 3/4, the sand of inoculated alfalfa has less Olsen-P than contrast, the change trend of Olsen-P content is concerned with the relative strength size of absorb Olsen-P by alfalfa root and dissolve Olsen-P by root exudates and hyphae interstate.

Possibilities of avoidance and control of bacterial plant diseases when using pathogen-tested (certified) or - treated planting material

NARCIS (Netherlands)

Janse, J.; Wenneker, M.

2002-01-01

Testing of planting material for freedom from phytopathogenic bacteria is an important, although not exclusive, method for control of bacterial diseases of plants. Ideally, pathogen-free or pathogen-/disease-resistant planting material is desirable, but this situation is not always possible on a

An oxidative burst and its attenuation by bacterial peroxidase activity is required for optimal establishment of the Arachis hypogaea-Bradyrhizobium sp. symbiosis.

Science.gov (United States)

Muñoz, V; Ibáñez, F; Figueredo, M S; Fabra, A

2016-07-01

The main purpose of this study was to determine whether the Arachis hypogaea L. root oxidative burst, produced at early stages of its symbiotic interaction with Bradyrhizobium sp. SEMIA 6144, and the bacterial antioxidant system are required for the successful development of this interaction. Pharmacological approaches were used to reduce both plant oxidative burst and bacterial peroxidase enzyme activity. In plants whose H2 O2 levels were decreased, a low nodule number, a reduction in the proportion of red nodules (%) and an increase in the bacteroid density were found. The symbiotic phenotype of plants inoculated with a Bradyrhizobium sp. SEMIA 6144 culture showing decreased peroxidase activity was also affected, since the biomass production, nodule number and percentage of red nodules in these plants were lower than in plants inoculated with Bradyrhizobium sp. control cultures. We demonstrated for the first time that the oxidative burst triggered at the early events of the symbiotic interaction in peanut, is a prerequisite for the efficient development of root nodules, and that the antioxidant system of bradyrhizobial peanut symbionts, particularly the activity of peroxidases, is counteracting this oxidative burst for the successful establishment of the symbiosis. Our results provide new insights into the mechanisms involved in the development of the symbiotic interaction established in A. hypogaea L. a legume infected in an intercellular way. © 2016 The Society for Applied Microbiology.

Phosphorus mobilizing consortium Mammoth P™ enhances plant growth

Science.gov (United States)

Bell, Colin; Mancini, Lauren M.; Lee, Melanie N.; Conant, Richard T.; Wallenstein, Matthew D.

2016-01-01

Phosphorus (P) is a critical nutrient used to maximize plant growth and yield. Current agriculture management practices commonly experience low plant P use efficiency due to natural chemical sorption and transformations when P fertilizer is applied to soils. A perplexing challenge facing agriculture production is finding sustainable solutions to deliver P more efficiently to plants. Using prescribed applications of specific soil microbial assemblages to mobilize soil bound—P to improve crop nutrient uptake and productivity has rarely been employed. We investigated whether inoculation of soils with a bacterial consortium developed to mobilize soil P, named Mammoth PTM, could increase plant productivity. In turf, herbs, and fruits, the combination of conventional inorganic fertilizer combined with Mammoth PTM increased productivity up to twofold compared to the fertilizer treatments without the Mammoth PTM inoculant. Jalapeño plants were found to bloom more rapidly when treated with either Mammoth P. In wheat trials, we found that Mammoth PTM by itself was able to deliver yields equivalent to those achieved with conventional inorganic fertilizer applications and improved productivity more than another biostimulant product. Results from this study indicate the substantial potential of Mammoth PTM to enhance plant growth and crop productivity. PMID:27326379

Drought response of Mucuna pruriens (L. DC. inoculated with ACC deaminase and IAA producing rhizobacteria.

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Aansa Rukya Saleem

Full Text Available Drought is one of the major constraints limiting agricultural production worldwide and is expected to increase in the future. Limited water availability causes significant effects to plant growth and physiology. Plants have evolved different traits to mitigate the stress imposed by drought. The presence of plant growth-promoting rhizobacteria (PGPR could play an important role in improving plant performances and productivity under drought. These beneficial microorganisms colonize the rhizosphere of plants and increase drought tolerance by lowering ethylene formation. In the present study, we demonstrate the potential to improve the growth of velvet bean under water deficit conditions of two different strains of PGPR with ACCd (1-Aminocyclopropane-1-Carboxylate deaminase activity isolated from rainfed farming system. We compared uninoculated and inoculated plants with PGPR to assess: a photosynthetic performance and biomass; b ACC content and ethylene emission from leaves and roots; c leaf isoprene emission. Our results provided evidence that under drought conditions inoculation with PGPR containing the ACCd enzyme could improve plant growth compared to untreated plants. Ethylene emission from roots and leaves of inoculated velvet bean plants was significantly lower than uninoculated plants. Moreover, isoprene emission increased with drought stress progression and was higher in inoculated plants compared to uninoculated counterparts. These findings clearly illustrate that selected PGPR strains isolated from rainfed areas could be highly effective in promoting plant growth under drought conditions by decreasing ACC and ethylene levels in plants.

Drought response of Mucuna pruriens (L.) DC. inoculated with ACC deaminase and IAA producing rhizobacteria.

Science.gov (United States)

Saleem, Aansa Rukya; Brunetti, Cecilia; Khalid, Azeem; Della Rocca, Gianni; Raio, Aida; Emiliani, Giovanni; De Carlo, Anna; Mahmood, Tariq; Centritto, Mauro

2018-01-01

Drought is one of the major constraints limiting agricultural production worldwide and is expected to increase in the future. Limited water availability causes significant effects to plant growth and physiology. Plants have evolved different traits to mitigate the stress imposed by drought. The presence of plant growth-promoting rhizobacteria (PGPR) could play an important role in improving plant performances and productivity under drought. These beneficial microorganisms colonize the rhizosphere of plants and increase drought tolerance by lowering ethylene formation. In the present study, we demonstrate the potential to improve the growth of velvet bean under water deficit conditions of two different strains of PGPR with ACCd (1-Aminocyclopropane-1-Carboxylate deaminase) activity isolated from rainfed farming system. We compared uninoculated and inoculated plants with PGPR to assess: a) photosynthetic performance and biomass; b) ACC content and ethylene emission from leaves and roots; c) leaf isoprene emission. Our results provided evidence that under drought conditions inoculation with PGPR containing the ACCd enzyme could improve plant growth compared to untreated plants. Ethylene emission from roots and leaves of inoculated velvet bean plants was significantly lower than uninoculated plants. Moreover, isoprene emission increased with drought stress progression and was higher in inoculated plants compared to uninoculated counterparts. These findings clearly illustrate that selected PGPR strains isolated from rainfed areas could be highly effective in promoting plant growth under drought conditions by decreasing ACC and ethylene levels in plants.

Variability of Effective Micro-organisms (EM) in bokashi and soil and effects on soil-borne plant pathogens

NARCIS (Netherlands)

Shin, Keumchul; Diepen, van G.; Blok, W.; Bruggen, van A.H.C.

2017-01-01

The microbial inoculant ‘Effective Microorganisms’ (EM) has been used to promote soil fertility and plant growth in agriculture. We tested effects of commercial EM products on suppression of soil-borne diseases, microbial activity and bacterial composition in organically managed sandy soils. EM was

Baby bottle steam sterilizers for disinfecting home nebulizers inoculated with non-tuberculous mycobacteria.

Science.gov (United States)

Towle, D; Callan, D A; Lamprea, C; Murray, T S

2016-03-01

Non-tuberculous mycobacteria (NTMb), present in environmental water sources, can contribute to respiratory infection in patients with chronic pulmonary disease. Contaminated nebulizers are a potential source of respiratory infection. Treatment with baby bottle steam sterilizers disinfects home nebulizers inoculated with bacterial pathogens but whether this method works for disinfection of NTMb is unclear. Baby bottle steam sterilization was compared with vigorous water washing for disinfecting home nebulizers inoculated with NTMb mixed with cystic fibrosis sputum. No NTMb was recovered from any nebulizers after steam treatment whereas viable NTMb grew after water washing, demonstrating that steam sterilization effectively disinfects NTMb-inoculated nebulizers. Copyright © 2015 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Azospirillum spp. from native forage grasses in Brazilian Pantanal floodplain: biodiversity and plant growth promotion potential.

Science.gov (United States)

Souza, Mayara S T; de Baura, Valter A; Santos, Sandra A; Fernandes-Júnior, Paulo Ivan; Reis Junior, Fábio B; Marques, Maria Rita; Paggi, Gecele Matos; da Silva Brasil, Marivaine

2017-04-01

A sustainable alternative to improve yield and the nutritive value of forage is the use of plant growth-promoting bacteria (PGPB) that release nutrients, synthesize plant hormones and protect against phytopathogens (among other mechanisms). Azospirillum genus is considered an important PGPB, due to the beneficial effects observed when inoculated in several plants. The aim of this study was to evaluate the diversity of new Azospirillum isolates and select bacteria according to the plant growth promotion ability in three forage species from the Brazilian Pantanal floodplain: Axonopus purpusii, Hymenachne amplexicaulis and Mesosetum chaseae. The identification of bacterial isolates was performed using specific primers for Azospirillum in PCR reactions and partial sequencing of the 16S rRNA and nifH genes. The isolates were evaluated in vitro considering biological nitrogen fixation (BNF) and indole-3-acetic acid (IAA) production. Based on the results of BNF and IAA, selected isolates and two reference strains were tested by inoculation. At 31 days after planting the plant height, shoot dry matter, shoot protein content and root volume were evaluated. All isolates were able to fix nitrogen and produce IAA, with values ranging from 25.86 to 51.26 mg N mL -1 and 107-1038 µmol L -1 , respectively. The inoculation of H. amplexicaulis and A. purpusii increased root volume and shoot dry matter. There were positive effects of Azospirillum inoculation on Mesosetum chaseae regarding plant height, shoot dry matter and root volume. Isolates MAY1, MAY3 and MAY12 were considered promising for subsequent inoculation studies in field conditions.

Relationships between mycorrhizas and antioxidant enzymes in citrus (citrus tangerina) seedlings inoculated with glomus mosseae

International Nuclear Information System (INIS)

Liu, C.Y.; Wu, Q.S.

2014-01-01

A potted experiment was conducted to evaluate the effects of an arbuscular mycorrhizal fungus (AMF), Glomus mosseae, on growth performance and superoxide dismutase (SOD) and catalase (CAT) activities of citrus (Citrus tangerina) seedlings. After five months of AMF inoculation, mycorrhizal colonization and vesicles, but not arbuscules and entry points, increased with the increase of inoculated mycorrhizal dosages among 5-40 g (32 spores/g dosage). Mycorrhizal inoculation with 10-40 g dosages significantly increased plant growth traits, including plant height, stem diameter, and shoot, root and total fresh weights. Higher leaf chlorophyll content was found in all the mycorrhizal plants, compared with the non-mycorrhizal plants. Inoculation with G. mosseae markedly decreased SOD and CAT activities of leaf and root, except an increase of either root CAT with the 20 g mycorrhizal treatment or root SOD with the 20 and 40 g mycorrhizal treatments. In addition, mycorrhizal colonization and vesicles significantly positively correlated with root SOD and without root CAT. We also discussed the relationships between mycorrhizal effects on antioxidant enzymes and growth environment of host plants. (author)

Inoculation of plant growth promoting rhizobia in Sudan grass (Sorghum × sudanense (Piper Stapf cv. Sudanense and millet (Pennisetum glaucum (L. R.Br. cv. BRS1501

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Rafael Goulart Machado

2018-01-01

Full Text Available Rhizobia are able to increase yield of non-leguminous species through production of phyto-stimulating substances. This study aimed to evaluate the inoculation effect of rhizobia UFRGS Lc348 and VP16 on millet and Sudan grass yield and germination, and verify the enrichment effect of culture medium with tryptophan, which leads on the rhizobium/plant interaction. Experiments in vitro and greenhouse conditions were conducted. In millet, the inoculation with VP16 grown in culture medium with or without tryptophan induces greater length of hypocotyl and epicotyl under in vitro conditions. UFRGS Lc348 treatment induces longer hypocotyls of millet under in vitro conditions. No effects were observed with the millet inoculation in greenhouse. In Sudan grass, inoculation with VP16 enriched with tryptophan increased dry matter in shoots of adult plants. In millet seedlings had achieved an increasing in elongation in vitro conditions, which could represent an adaptive advantage in the search for water and nutrients in the rhizospheric environment during the initial growth of millet. Similarly, if verified in field conditions, Sudan grass had achieved an increasing in greenhouse conditions with the inoculation of tryptophan-enriched VP16, which could be correlated with a significant gain in crop yield. Therefore, these relationships between tryptophan-enriched VP16 and Sudan grass should be verified in subsequent studies under field conditions.

Improvement of cadmium phytoremediation after soil inoculation with a cadmium-resistant Micrococcus sp.

Science.gov (United States)

Sangthong, Chirawee; Setkit, Kunchaya; Prapagdee, Benjaphorn

2016-01-01

Cadmium-resistant Micrococcus sp. TISTR2221, a plant growth-promoting bacterium, has stimulatory effects on the root lengths of Zea mays L. seedlings under toxic cadmium conditions compared to uninoculated seedlings. The performance of Micrococcus sp. TISTR2221 on promoting growth and cadmium accumulation in Z. mays L. was investigated in a pot experiment. The results indicated that Micrococcus sp. TISTR2221significantly promoted the root length, shoot length, and dry biomass of Z. mays L. transplanted in both uncontaminated and cadmium-contaminated soils. Micrococcus sp. TISTR2221 significantly increased cadmium accumulation in the roots and shoots of Z. mays L. compared to uninoculated plants. At the beginning of the planting period, cadmium accumulated mainly in the shoots. With a prolonged duration of cultivation, cadmium content increased in the roots. As expected, little cadmium was found in maize grains. Soil cadmium was significantly reduced with time, and the highest percentage of cadmium removal was found in the bacterial-inoculated Z. mays L. after transplantation for 6 weeks. We conclude that Micrococcus sp. TISTR2221 is a potent bioaugmenting agent, facilitating cadmium phytoextraction in Z. mays L.

Inheritance of bacterial spot resistance in Capsicum annuum var. annuum.

Science.gov (United States)

Silva, L R A; Rodrigues, R; Pimenta, S; Correa, J W S; Araújo, M S B; Bento, C S; Sudré, C P

2017-04-20

Since 2008, Brazil is the largest consumer of agrochemicals, which increases production costs and risks of agricultural products, environment, and farmers' contamination. Sweet pepper, which is one of the main consumed vegetables in the country, is on top of the list of the most sprayed crops. The bacterial spot, caused by Xanthomonas spp, is one of the most damaging diseases of pepper crops. Genetic resistant consists of a suitable way of disease control, but development of durable resistant cultivars as well as understanding of plant-bacterium interaction is being a challenge for plant breeders and pathologists worldwide. Inheritance of disease resistance is often variable, depending on genetic background of the parents. The knowledge of the genetic base controlling such resistance is the first step in a breeding program aiming to develop new genotypes, bringing together resistance and other superior agronomic traits. This study reports the genetic basis of bacterial spot resistance in Capsicum annuum var. annuum using mean generation analysis from crosses between accessions UENF 2285 (susceptible) and UENF 1381 (resistant). The plants of each generation were grown in a greenhouse and leaflets were inoculated with bacterial strain ENA 4135 at 10 5 CFU/mL in 1.0 cm 2 of the mesophyll. Evaluations were performed using a scoring scale whose grades ranged from 1.0 (resistant) to 5.0 (susceptible), depending on symptom manifestation. Genetic control of bacterial spot has a quantitative aspect, with higher additive effect. The quantitative analysis showed that five genes were the minimum number controlling bacterial spot resistance. Additive effect was higher (6.06) than dominant (3.31) and explained 86.36% of total variation.

Bacterial Endophytes Isolated from Plants in Natural Oil Seep Soils with Chronic Hydrocarbon Contamination.

Science.gov (United States)

Lumactud, Rhea; Shen, Shu Yi; Lau, Mimas; Fulthorpe, Roberta

2016-01-01

The bacterial endophytic communities of four plants growing abundantly in soils highly contaminated by hydrocarbons were analyzed through culturable and culture-independent means. Given their tolerance to the high levels of petroleum contamination at our study site, we sought evidence that Achillea millefolium, Solidago canadensis, Trifolium aureum, and Dactylis glomerata support high levels of hydrocarbon degrading endophytes. A total of 190 isolates were isolated from four plant species. The isolates were identified by partial 16S rDNA sequence analysis, with class Actinobacteria as the dominant group in all species except S. canadensis, which was dominated by Gammaproteobacteria. Microbacterium foliorum and Plantibacter flavus were present in all the plants, with M. foliorum showing predominance in D. glomerata and both endophytic bacterial species dominated T. aureum. More than 50% of the isolates demonstrated degradative capabilities for octanol, toluene, naphthalene, kerosene, or motor oil based on sole carbon source growth screens involving the reduction of tetrazolium dye. P. flavus isolates from all the sampled plants showed growth on all the petroleum hydrocarbons (PHCs) substrates tested. Mineralization of toluene and naphthalene was confirmed using gas-chromatography. 16S based terminal restriction fragment length polymorphism analysis revealed significant differences between the endophytic bacterial communities showing them to be plant host specific at this site. To our knowledge, this is the first account of the degradation potential of bacterial endophytes in these commonly occurring pioneer plants that were not previously known as phytoremediating plants.

Bacterial endophytes isolated from plants in natural oil seep soils with chronic hydrocarbon contamination

Directory of Open Access Journals (Sweden)

Rhea eLumactud

2016-05-01

Full Text Available The bacterial endophytic communities of four plants growing abundantly in soils highly contaminated by hydrocarbons were analyzed through culturable and and culture-independent means. Given their tolerance to the high levels of petroleum contamination at our study site, we sought evidence that Achillea millefolium, Solidago canadensis, Trifolium aureum and Dactylis glomerata support high levels of hydrocarbon degrading endophytes. A total of 190 isolates were isolated from four plant species. The isolates were identified by partial 16S rDNA sequence analysis, with class Actinobacteria as the dominant group in all species except Solidago canadensis, which was dominated by Gammaproteobacteria. Microbacterium foliorum and Plantibacter flavus were present in all the plants, with M. foliorum showing predominance in D. glomerata and both endophytic bacterial species dominated T. aureum. More than 50% of the isolates demonstrated degradative capabilities for octanol, toluene, naphthalene, kerosene or motor oil based on sole carbon source growth screens involving the reduction of tetrazolium dye. P. flavus isolates from all the sampled plants showed growth on all the petroleum hydrocarbons substrates tested. Mineralization of toluene and naphthalene was confirmed using gas-chromatography. 16S based terminal restriction fragment length polymorphism analysis revealed significant differences between the endophytic bacterial communities showing them to be plant host specific at this site. To our knowledge, this is the first account of the degradation potential of bacterial endophytes in these commonly occurring pioneer plants that were not previously known as phytoremediating plants.

Bacterial endophytes of perennial crops for management of plant disease

OpenAIRE

Melnick, Rachel L.; Bailey, B.A.; Backman, Paul A.

2013-01-01

Metadata only record Bacterial endophytes, microorganisms which inhabit the internal tissues of plants, can suppress disease and are often used as a biological control in annual crops. Less research, however, has been applied to the use of bacterial endophytes to prevent disease in perennial crops, which presents a more complex challenge. However, exploration of their potential as a biological control in perennial crops has been limited. This chapter assembles current knowledge on the subj...

Effect of bacterial root symbiosis and urea as source of nitrogen on performance of soybean plants grown hydroponically for Bioregenerative Life Support Systems (BLSSs).

Science.gov (United States)

Paradiso, Roberta; Buonomo, Roberta; Dixon, Mike A; Barbieri, Giancarlo; De Pascale, Stefania

2015-01-01

Soybean is traditionally grown in soil, where root symbiosis with Bradyrhizobium japonicum can supply nitrogen (N), by means of bacterial fixation of atmospheric N2. Nitrogen fertilizers inhibit N-fixing bacteria. However, urea is profitably used in soybean cultivation in soil, where urease enzymes of telluric microbes catalyze the hydrolysis to ammonium, which has a lighter inhibitory effect compared to nitrate. Previous researches demonstrated that soybean can be grown hydroponically with recirculating complete nitrate-based nutrient solutions. In Space, urea derived from crew urine could be used as N source, with positive effects in resource procurement and waste recycling. However, whether the plants are able to use urea as the sole source of N and its effect on root symbiosis with B. japonicum is still unclear in hydroponics. We compared the effect of two N sources, nitrate and urea, on plant growth and physiology, and seed yield and quality of soybean grown in closed-loop Nutrient Film Technique (NFT) in growth chamber, with or without inoculation with B. japonicum. Urea limited plant growth and seed yield compared to nitrate by determining nutrient deficiency, due to its low utilization efficiency in the early developmental stages, and reduced nutrients uptake (K, Ca, and Mg) throughout the whole growing cycle. Root inoculation with B. japonicum did not improve plant performance, regardless of the N source. Specifically, nodulation increased under fertigation with urea compared to nitrate, but this effect did not result in higher leaf N content and better biomass and seed production. Urea was not suitable as sole N source for soybean in closed-loop NFT. However, the ability to use urea increased from young to adult plants, suggesting the possibility to apply it during reproductive phase or in combination with nitrate in earlier developmental stages. Root symbiosis did not contribute significantly to N nutrition and did not enhance the plant ability to use

Recombinant Plants Provide a New Approach to the Production of Bacterial Polysaccharide for Vaccines

Science.gov (United States)

Smith, Claire M.; Fry, Stephen C.; Gough, Kevin C.; Patel, Alexandra J. F.; Glenn, Sarah; Goldrick, Marie; Roberts, Ian S.; Andrew, Peter W.

2014-01-01

Bacterial polysaccharides have numerous clinical or industrial uses. Recombinant plants could offer the possibility of producing bacterial polysaccharides on a large scale and free of contaminating bacterial toxins and antigens. We investigated the feasibility of this proposal by cloning and expressing the gene for the type 3 synthase (cps3S) of Streptococcus pneumoniae in Nicotinia tabacum, using the pCambia2301 vector and Agrobacterium tumefaciens-mediated gene transfer. In planta the recombinant synthase polymerised plant-derived UDP-glucose and UDP-glucuronic acid to form type 3 polysaccharide. Expression of the cps3S gene was detected by RT-PCR and production of the pneumococcal polysaccharide was detected in tobacco leaf extracts by double immunodiffusion, Western blotting and high-voltage paper electrophoresis. Because it is used a component of anti-pneumococcal vaccines, the immunogenicity of the plant-derived type 3 polysaccharide was tested. Mice immunised with extracts from recombinant plants were protected from challenge with a lethal dose of pneumococci in a model of pneumonia and the immunised mice had significantly elevated levels of serum anti-pneumococcal polysaccharide antibodies. This study provides the proof of the principle that bacterial polysaccharide can be successfully synthesised in plants and that these recombinant polysaccharides could be used as vaccines to protect against life-threatening infections. PMID:24498433

Hydrolytic bacteria in mesophilic and thermophilic degradation of plant biomass

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Zverlov, Vladimir V.; Hiegl, Wolfgang; Koeck, Daniela E.; Koellmeier, Tanja; Schwarz, Wolfgang H. [Department of Microbiology, Technische Universitaet Muenchen, Freising-Weihenstephan (Germany); Kellermann, Josef [Max Planck Institute for Biochemistry, Am Klopferspitz, Martinsried (Germany)

2010-12-15

Adding plant biomass to a biogas reactor, hydrolysis is the first reaction step in the chain of biological events towards methane production. Maize silage was used to enrich efficient hydrolytic bacterial consortia from natural environments under conditions imitating those in a biogas plant. At 55-60 C a more efficient hydrolyzing culture could be isolated than at 37 C. The composition of the optimal thermophilic bacterial consortium was revealed by sequencing clones from a 16S rRNA gene library. A modified PCR-RFLP pre-screening method was used to group the clones. Pure anaerobic cultures were isolated. 70% of the isolates were related to Clostridium thermocellum. A new culture-independent method for identification of cellulolytic enzymes was developed using the isolation of cellulose-binding proteins. MALDI-TOF/TOF analysis and end-sequencing of peptides from prominent protein bands revealed cellulases from the cellulosome of C. thermocellum and from a major cellulase of Clostridium stercorarium. A combined culture of C. thermocellum and C. stercorarium was shown to excellently degrade maize silage. A spore preparation method suitable for inoculation of maize silage and optimal hydrolysis was developed for the thermophilic bacterial consortium. This method allows for concentration and long-term storage of the mixed culture for instance for inoculation of biogas fermenters. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Root Proteomic Analysis of Grapevine Rootstocks Inoculated with Rhizophagus irregularis and Fusarium oxysporum f. sp. herbemontis

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Elisa Vilvert

Full Text Available ABSTRACT Grapevine decline and death caused by the pathogenic fungus Fusarium oxysporum f. sp. herbemontis is among the main phytosanitary problem for viticulture in southern Brazil. The eradication of infected plants is presently the most common procedure for disease control in vineyards. Inoculation with arbuscular mycorrhizal fungi is an option to reduce or neutralize the negative impacts of soil pathogenic microorganisms, but the mechanisms of plant response involved in this process are not yet completely elucidated. In order to better understand these mechanisms, an experiment was carried out to identify proteins related to plant defence induced by the mycorrhizal fungus after infection with the pathogenic fungus. We used the grapevine rootstocks SO4 and R110 (susceptible and resistant to the pathogenic fungus, respectively inoculated or not inoculated with the mycorrhizal fungus Rhizophagus irregularis, and inoculated or not inoculated with Fusarium oxysporum f. sp. herbemontis. Growth of the rootstocks’ shoot and root and presence of pathogenic symptoms were evaluated. The protein profiles of roots were characterized by two-dimensional electrophoresis and proteins were identified using mass spectrometry. The grapevine rootstocks inoculated with R. irregularis had higher biomass production and lower level of pathogenic symptoms. The R110 rootstock differentially accumulated 73 proteins, while SO4 accumulated 59 proteins. Nine plant-defence proteins were expressed by SO4 rootstock, and six were expressed by R110 rootstock plants. The results confirm the effect of mycorrhizal fungi in plant growth promotion and their potential for biological control against soil pathogenic fungus. Protein expression is dependent on rootstock characteristics and on the combination of plant material with the fungi.

Effect of inoculum size, bacterial species, type of surfaces and contact time to the transfer of foodborne pathogens from inoculated to non-inoculated beef fillets via food processing surfaces.

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Gkana, E; Chorianopoulos, N; Grounta, A; Koutsoumanis, K; Nychas, G-J E

2017-04-01

The objective of the present study was to determine the factors affecting the transfer of foodborne pathogens from inoculated beef fillets to non-inoculated ones, through food processing surfaces. Three different levels of inoculation of beef fillets surface were prepared: a high one of approximately 10 7  CFU/cm 2 , a medium one of 10 5  CFU/cm 2 and a low one of 10 3  CFU/cm 2 , using mixed-strains of Listeria monocytogenes, or Salmonella enterica Typhimurium, or Escherichia coli O157:H7. The inoculated fillets were then placed on 3 different types of surfaces (stainless steel-SS, polyethylene-PE and wood-WD), for 1 or 15 min. Subsequently, these fillets were removed from the cutting boards and six sequential non-inoculated fillets were placed on the same surfaces for the same period of time. All non-inoculated fillets were contaminated with a progressive reduction trend of each pathogen's population level from the inoculated fillets to the sixth non-inoculated ones that got in contact with the surfaces, and regardless the initial inoculum, a reduction of approximately 2 log CFU/g between inoculated and 1st non-inoculated fillet was observed. S. Typhimurium was transferred at lower mean population (2.39 log CFU/g) to contaminated fillets than E. coli O157:H7 (2.93 log CFU/g), followed by L. monocytogenes (3.12 log CFU/g; P < 0.05). Wooden surfaces (2.77 log CFU/g) enhanced the transfer of bacteria to subsequent fillets compared to other materials (2.66 log CFU/g for SS and PE; P < 0.05). Cross-contamination between meat and surfaces is a multifactorial process strongly depended on the species, initial contamination level, kind of surface, contact time and the number of subsequent fillet, according to analysis of variance. Thus, quantifying the cross-contamination risk associated with various steps of meat processing and food establishments or households can provide a scientific basis for risk management of such products. Copyright © 2016 Elsevier Ltd

Characterization of plant-growth promoting diazotrophic bacteria isolated from field grown Chinese cabbage under different fertilization conditions.

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Yim, Woo-Jong; Poonguzhali, Selvaraj; Madhaiyan, Munusamy; Palaniappan, Pitchai; Siddikee, M A; Sa, Tongmin

2009-04-01

Diazotrophic bacteria isolated from the rhizosphere of Chinese cabbage were assessed for other plant growth promoting characteristics viz., production of IAA, ethylene, ACC deaminase, phosphate solubilization, and gnotobiotic root elongation. Their effect on inoculation to Chinese cabbage was also observed under growth chamber conditions. A total of 19 strains that showed higher nitrogenase activity identified by 16S rRNA gene sequence analysis were found to be the members of the genera Pseudomonas and Agrobacterium belonging to alpha- and gamma-Proteobacteria groups. These strains were also efficient in producing IAA and ACC deaminase though they produced low levels of ethylene and no phosphate solubilization. In addition, inoculation of selected diazotrophic bacterial strains significantly increased seedling length, dry weight, and total nitrogen when compared to uninoculated control. The colonization of crop plants by diazotrophic bacteria can be affected by many biotic and abiotic factors, and further studies are oriented towards investigating the factors that could influence the establishment of a selected bacterial community.

Rhizobial Inoculation, Alone or Coinoculated with Azospirillum brasilense, Promotes Growth of Wetland Rice

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Leandro Hahn

Full Text Available ABSTRACT Rhizobia and associative bacteria promote growth in rice plants (Oryza sativa L. through a series of mechanisms, but most studies on inoculation have been performed based on inoculation with these bacteria in a separate or singular manner. The objective of this study was to assess the efficiency of single/isolated inoculation and inoculation combined with symbiotic rhizobia from forage legume and with Azospirillum brasilense on promoting growth and the root colonization process in wetland rice. Two rhizobia among four isolates from a greenhouse and a laboratory experiment were selected that efficiently promoted seed germination and rice plant growth in a sterilized substrate and in soil. The two most efficient isolates (UFRGS Vp16 and UFRGS Lc348 were inoculated alone or in combination with a commercial product containing A. brasilense in two field experiments using two wetland rice cultivars over two growing seasons. In the field experiments, these isolates coinoculated with A. brasilense promoted larger increases in the agronomic variables of wetland rice compared to the control without inoculation. Confocal laser microscopy confirmed the presence of inoculated bacteria tagged with gfp (UFRGS Vp16, UFRGS Lc348, and A. brasilense colonizing the root surface of the rice seedlings, mainly in the root hairs and lateral roots.

Biological control of bacterial spot of tomato by saprobe fungi from semi-arid areas of northeastern Brazil

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Douglas Casaroto Peitl

2017-06-01

Full Text Available Bacterial spot of tomato, caused by Xanthomonas spp., is a common disease in tomato fields that causes significant economic losses. Due to the difficulty with control of bacterial spot by conventional methods, new techniques such as biological control and induction of resistance are gaining prominence. This study aimed to select saprobe fungi from semi-arid regions of the Brazilian Northeast for the biological control of bacterial spot of tomato. To select the best isolates to control bacterial spot, a greenhouse experiment was initially conducted. Tomato plants (‘Santa Cruz Kada’ were treated with filtrates of 25 saprobe fungi and inoculated three days later with Xanthomonas euvesicatoria. Filtrates of Memnoniella levispora, Periconia hispidula, Zygosporium echinosporum, and Chloridium virescens var. virescens were selected as the most effective. Filtrates and volatile compounds from these four isolates were tested for their antibacterial activity in cultures of X. euvesicatoria and in tomato plants (‘Santa Cruz Kada’ inoculated with X. euvesicatoria. In vitro, the addition of nonvolatile fungal metabolites into the culture medium at 5% and 50% (v/v inhibited bacterial growth by 28.9% and 53.8%, respectively. The volatile compounds produced by C. virescens var. virescens reduced the number of colony-forming units of X. euvesicatoria by 25.9%. In vivo, all treatments reduced from 62.4 to 71.3% the area under bacterial spot progress curve, showing the same control efficacy as the commercial resistance inducer used as a positive control (acibenzolar-S-methyl. Systemicity of the fungal filtrates was confirmed in a separate experiment, where application of the treatments exclusively to the third leaf decreased the severity of the disease on the fourth leaf (except for C. virescens var. virescens. These results show that M. levispora, P. hispidula, Z. echinosporum, and C. virescens var. virescens are potential biocontrol agents against

Sonication reduces the attachment of Salmonella Typhimurium ATCC 14028 cells to bacterial cellulose-based plant cell wall models and cut plant material.

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Tan, Michelle S F; Rahman, Sadequr; Dykes, Gary A

2017-04-01

This study investigated the removal of bacterial surface structures, particularly flagella, using sonication, and examined its effect on the attachment of Salmonella Typhimurium ATCC 14028 cells to plant cell walls. S. Typhimurium ATCC 14028 cells were subjected to sonication at 20 kHz to remove surface structures without affecting cell viability. Effective removal of flagella was determined by staining flagella of sonicated cells with Ryu's stain and enumerating the flagella remaining by direct microscopic counting. The attachment of sonicated S. Typhimurium cells to bacterial cellulose-based plant cell wall models and cut plant material (potato, apple, lettuce) was then evaluated. Varying concentrations of pectin and/or xyloglucan were used to produce a range of bacterial cellulose-based plant cell wall models. As compared to the non-sonicated controls, sonicated S. Typhimurium cells attached in significantly lower numbers (between 0.5 and 1.0 log CFU/cm 2 ) to all surfaces except to the bacterial cellulose-only composite without pectin and xyloglucan. Since attachment of S. Typhimurium to the bacterial cellulose-only composite was not affected by sonication, this suggests that bacterial surface structures, particularly flagella, could have specific interactions with pectin and xyloglucan. This study indicates that sonication may have potential applications for reducing Salmonella attachment during the processing of fresh produce. Copyright © 2016 Elsevier Ltd. All rights reserved.

Single and mixed formulations of inoculants with diazotrophic bacteria, under different nitrogen rates and on the paddy rice crop

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Paula Bianchet

2013-12-01

Full Text Available The use of diazotrophic bacteria as a biological input for the production of paddy rice can reduce nitrogen fertilizer applications and contribute to plant development. The use of mixed inoculants’ formulations can increase the efficiency of nitrogen fixation biological process. The objective of this study was to evaluate the effect of single and mixed formulations of inoculants with diazotrophic bacteria on the initial growth of paddy rice plants under different levels of N. The experiment was set in a greenhouse. Treatments consisted of four types of inoculation (no inoculation, inoculation with the isolated AI UDESC 27, inoculation with the isolated FE UDESC 22, and inoculation with the mixed formulation of isolated AI UDESC UDESC 27 and FE UDESC 22; and two levels of mineral nitrogen (30 and 60 mg kg-1 of N. The cultivar used was Epagri 109, which presents late maturity (over 140 days and high yield potential. Treatments were arranged in a factorial design (4 x 2 with five replicates. The experimental design was completely randomized. Inoculation with diazotrophic bacteria reduced by 18% and 26% shoot and root dry matter of rice plants, respectively. Plants also presented lower root area and volume when they were inoculated. There was no significant effect of inoculation and nitrogen rates on the number of leaves and tillers produced per plant or shoot nitrogen accumulation. The results showed that the isolated used in this work were not effective to stimulate shoot and root growth of cv Epagri 109, regardless of formulation type and rate of N.

Performance of pineapple slips inoculated with diazotrophic phosphate-solubilizing bacteria and rock phosphate

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Lílian Estrela Borges Baldotto

2014-06-01

Full Text Available Besides fixing N2, some diazotrophic bacteria or diazotrophs, also synthesize organic acids and are able to solubilize rock phosphates, increasing the availability of P for plants. The application of these bacteria to pineapple leaf axils in combination with rock phosphate could increase N and P availability for the crop, due to the bacterial activity of biological nitrogen fixation and phosphate solubilization. The objectives of this study were: (i to select and characterize diazotrophs able to solubilize phosphates in vitro and (ii evaluate the initial performance of the pineapple cultivars Imperial and Pérola in response to inoculation with selected bacteria in combination with rock phosphate. The experiments were conducted at Universidade Estadual do Norte Fluminense Darcy Ribeiro, in 2009. In the treatments with bacteria the leaf contents of N, P and K were higher than those of the controls, followed by an increase in plant growth. These results indicate that the combined application of diazotrophic phosphate-solubilizing bacteria Burkholderia together with Araxá rock phosphate can be used to improve the initial performance of pineapple slips.

Population dynamics of bacteria associated with different strains of the pine wood nematode Bursaphelenchus xylophilus after inoculation in maritime pine (Pinus pinaster).

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Roriz, Mariana; Santos, Carla; Vasconcelos, Marta W

2011-08-01

For a long time it was thought that Bursaphelenchus xylophilus was the only agent of the pine wilt disease. Recently, it was discovered that there are bacteria associated with the nematodes that contribute to the pathogenesis of this disease, mainly through the release of toxins that promote the death of the pines. Among the species most commonly found, are bacteria belonging to the Bacillus, Pantoea, Pseudomonas and Xanthomonas genera. The main objective of this work was to study the effect of inoculation of maritime pine (Pinus pinaster) with four different nematode isolates, in the bacterial population of nematodes and trees, at different stages of disease progression. The monitoring of progression of disease symptoms was also recorded. Also, the identification of bacteria isolated from the xylem of trees and the surface of nematodes was performed by classical identification methods, by the API20E identification system and by sequencing of bacterial DNA. The results showed that for the symptoms progression, the most striking difference was observed for the pines inoculated with the avirulent isolate, C14-5, which led to a slower and less severe aggravation of symptoms than in pines inoculated with the virulent isolates. In general, it was found that bacterial population, inside the tree, increased with disease progression. A superior bacterial quantity was isolated from pines inoculated with the nematode isolates HF and 20, and, comparatively, few bacteria were isolated from pines inoculated with the avirulent isolate. The identification system API20E was insufficient in the identification of bacterial species; Enterobacter cloacae species was identified in 79% of the isolated bacterial colonies and seven of these colonies could not be identified by this method. Molecular identification methods, through bacterial DNA sequencing, allowed a more reliable identification: eleven different bacterial species within the Bacillus, Citrobacter, Enterobacter, Escherichia

Mycorrhizal inoculation affects the phytochemical content in strawberry fruits

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Ana Paula Cecatto

2016-04-01

Full Text Available The aim of this research was to evaluate the effect of the inoculation date of arbuscular mycorrhizal fungi on the fruit quality and the content of phytochemicals in a strawberry soilless growing system. The experiment was performed in Huelva (Spain and was conducted in a greenhouse on the La Rábida Campus of Huelva University under natural light and temperature from October 2013 to June 2014. Three short-day strawberry cultivars (‘Splendor’, ‘Sabrina’ and ‘Fortuna’ were grown in polyethylene bags filled with coconut fibres. Randomized block design, with 3 repetitions and factorial arrangement (3 cultivars x 3 treatments, was established. Each replicate consisted of one bag with 12 plants supporting structures at 40 cm height. The treatments were: T1 = mycorrhizal inoculation in the transplantation; T2 = mycorrhizal inoculation 30 days after transplantation (DAT; and T0 = control treatment, without inoculation. Arbuscular mycorrhizal fungi inoculation significantly affected the contents of anthocyanin and phenolics. When the inoculation is performed in the transplantation, the fruits showed a high content of anthocyanin and total phenolics. The mycorrhizal inoculation influences decreasing the acidity in fruit throughout the growing season and increase firmness only during the early stage of production.

Restructuring of endophytic bacterial communities in grapevine yellows-diseased and recovered Vitis vinifera L. plants.

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Bulgari, Daniela; Casati, Paola; Crepaldi, Paola; Daffonchio, Daniele; Quaglino, Fabio; Brusetti, Lorenzo; Bianco, Piero Attilio

2011-07-01

Length heterogeneity-PCR assays, combined with statistical analyses, highlighted that the endophytic bacterial community associated with healthy grapevines was characterized by a greater diversity than that present in diseased and recovered plants. The findings suggest that phytoplasmas can restructure the bacterial community by selecting endophytic strains that could elicit a plant defense response.

PCR-based analysis of disease in tomato singly or mixed inoculated with Fusarium oxysporum f. sp. lycopersici races 1 and 2

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OLUSEGUN SAMUEL BALOGUN

2008-07-01

Full Text Available The pathogenic response of two tomato cultivars to races of Fusarium oxysporum f. sp.. lycopersici (cv. Momotaro, insensitive to race 1 of the pathogen, and cv. Ponderosa sensitive to race 1, was studied in greenhouse and laboratory experiments by inoculating the cultivars singly with race 1 or race 2, and in mixed inoculation with the two races of the pathogen. A pre-symptom PCR assay two weeks after inoculation showed that a fragment of the intergenic spacer region (IGS of ribosomal DNA was amplifi ed by DNA templates from leaf samples of cv. Momotaro tomato plants inoculated with only race 2, or with race 1+2, but in the cv. Ponderosa the fragment was amplifi ed only in plants inoculated with race 1+2. Race-specifi c analysis using the sp13 and sp23 primers confi rmed that the amplifi ed fragment was from race 2 in cv. Momotaro and from races 1+2 in cv. Ponderosa. Later wilt symptoms mirrored the pre-symptom and post-symptom molecular analytical results: cv. Momotaro plants inoculated with only race 1 remained symptomless, while the ‘Momotaro’ plants inoculated with both races (1+2 did not manifest more severe wilt symptoms than plants inoculated with race 2 alone; cv. Ponderosa plants that were mixed-inoculated with race 1+2 manifested more severe symptoms, and at an earlier date than plants inoculated with only race 2. Growth parameters such as number of leaves and plant height showed the race 1+2 infected cv. Ponderosa were significantly retarded in growth, suggesting that significant synergism between the fungal races in tomato pathosystem can occur only when the host cultivar is sensitive to both races. An additional important finding is that pre-symptom leaf sampling of apparently healthy plants is useful in PCR diagnostic analysis to predict impending fusarial wilt outbreaks in tomato especially in infested soil.

Adoption of Calliandra calothyrsus for fodder and it's Inoculation Potential on Farms in Kenya

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Kiptot, E; Wanjiku, J; Obonyo, E; Odee, D.W

2007-01-01

In Kenya, productivity of dairy animals is mostly limited by inadequate nutrition especially proteins. To improve feed quality, the use of fodder trees is a preferred option. One of the most widely used fodder tree is calliandra calothyrsus (calliandra) whose productivity can be improved through rhizobia inoculation. A study was initiated to assess farmers' management practices and utilization of calliandra as well as to elicit their knowledge on it's inoculation. Survey sites were identified were identified in areas where calliandra had been previously introduced in central and western regions of Kenya. Results indicated that, for the first establishment of calliandra trees (NGOs) 68.3% of the farmers acquired seedlings from research institutions as well as Non-Governmental Organizations (NGOs) working within the research area. During subsequent establishments, reported only in central region a reverse trend was observed with 73% of farmers acquiring seedlings from private and individual nurseries. A majority of farmers (56%) planted calliandra on contours and 78% used it for fodder, while 22% had no knowledge of food potential. About 41% of farmers from central region had planted inoculated seedlings and only 1.6% from the western region had inoculants. Though the inoculant had been provided free, 47% of the farmers were willing to purchase it if made available. In central region calliandra was highly utilized for dairy animals consequently motivating farmers to expand planting. Contour planting was preferred niche due to the perceived low competition with associate crops for space and growth parameters. The study concluded that though calliandra was accepted as a fodder tree, a knowledge gap existed on farms on the role of rhizobia inoculation in productivity. There is therefore an urgent need to sensitize on the benefits of inoculation

Effect of progressive inoculation of fauna-free sheep with holotrich protozoa and total-fauna on rumen fermentation, microbial diversity and methane emissions.

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Belanche, Alejandro; de la Fuente, Gabriel; Newbold, Charles J

2015-03-01

Rumen methanogenesis represents an energy waste for the ruminant and an important source of greenhouse gas; thus, integrated studies are needed to fully understand this process. Eight fauna-free sheep were used to investigate the effect of successive inoculation with holotrich protozoa then with total fauna on rumen methanogenesis. Holotrichs inoculation neither altered rumen fermentation rate nor diet digestibility, but increased concentrations of acetate (+15%), butyrate (+57%), anaerobic fungi (+0.82 log), methanogens (+0.41 log) and methanogenesis (+54%). Further inoculation with total fauna increased rumen concentrations of protozoa (+1.0 log), bacteria (+0.29 log), anaerobic fungi (+0.78 log), VFA (+8%), ammonia and fibre digestibility (+17%) without affecting levels of methanogens or methanogenesis. Rumen methanogens population was fairly stable in terms of structure and diversity, while the bacterial community was highly affected by the treatments. Inoculation with holotrich protozoa increased bacterial diversity. Further inoculation with total fauna lowered bacterial diversity but increased concentrations of certain propionate and lactate-producing bacteria, suggesting that alternative H2 sinks could be relevant. This experiment suggests that holotrich protozoa have a greater impact on rumen methanogenesis than entodiniomorphids. Thus, further research is warranted to understand the effect of holotrich protozoa on methane formation and evaluate their elimination from the rumen as a potential methane mitigation strategy. © Federation of European Microbiological Society 2014.

Artificially accelerating the reversal of desertification: cyanobacterial inoculation facilitates the succession of vegetation communities.

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Lan, Shubin; Zhang, Qingyi; Wu, Li; Liu, Yongding; Zhang, Delu; Hu, Chunxiang

2014-01-01

Desertification has been recognized as a global environmental problem, and one region experiencing ongoing desertification is the eastern edge of Qubqi Desert (Inner Mongolia). To investigate the facilitating effects of cyanobacterial inoculation technology on the desertification control along this steppe-desert transition region, artificial cyanobacterial crusts were constructed with two filamentous cyanobacteria 3 and 8 years ago combined with Salix planting. The results showed that no crusts formed after 3 years of fixation only with Salix planting, whereas after cyanobacterial inoculation, the crusts formed quickly and gradually succeed to moss crusts. During that course, topsoil environments were gradually improved, providing the necessary material basis for the regeneration of vascular plants. In this investigation, total 27 species of vascular plants had regenerated in the experimental region, mainly belonging to Asteraceae, Poaceae, Chenopodiaceae and Leguminosae. Using space time substitution, the dominant species along with the application of cyanobacterial inoculation technology succeeded from Agriophyllum squarrosum ultimately to Leymus chinensis. In addition, it was found that the shady side of the dunes is more conducive to crust development and succession of vegetation communities. Conclusively, our results indicate artificial cyanobacterial inoculation technology is an effective and desirable path for desertification control.

Endophytic Herbaspirillum seropedicae expresses nif genes in gramineous plants.

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Roncato-Maccari, Lauren D B; Ramos, Humberto J O; Pedrosa, Fabio O; Alquini, Yedo; Chubatsu, Leda S; Yates, Marshall G; Rigo, Liu U; Steffens, Maria Berenice R; Souza, Emanuel M

2003-07-01

Abstract The interactions between maize, sorghum, wheat and rice plants and Herbaspirillum seropedicae were examined microscopically following inoculation with the H. seropedicae LR15 strain, a Nif(+) (Pnif::gusA) mutant obtained by the insertion of a gusA-kanamycin cassette into the nifH gene of the H. seropedicae wild-type strain. The expression of the Pnif::gusA fusion was followed during the association of the diazotroph with the gramineous species. Histochemical analysis of seedlings of maize, sorghum, wheat and rice grown in vermiculite showed that strain LR15 colonized root surfaces and inner tissues. In early steps of the endophytic association, H. seropedicae colonized root exudation sites, such as axils of secondary roots and intercellular spaces of the root cortex; it then occupied the vascular tissue and there expressed nif genes. The expression of nif genes occurred in roots, stems and leaves as detected by the GUS reporter system. The expression of nif genes was also observed in bacterial colonies located in the external mucilaginous root material, 8 days after inoculation. Moreover, the colonization of plant tissue by H. seropedicae did not depend on the nitrogen-fixing ability, since similar numbers of cells were isolated from roots or shoots of the plants inoculated with Nif(+) or Nif(-) strains.

Physiological and biochemical perspectives of non-salt tolerant plants during bacterial interaction against soil salinity.

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Radhakrishnan, Ramalingam; Baek, Kwang Hyun

2017-07-01

Climatic changes on earth affect the soil quality of agricultural lands, especially by increasing salt deposition in soil, which results in soil salinity. Soil salinity is a major challenge to growth and reproduction among glycophytes (including all crop plants). Soil bacteria present in the rhizosphere and/or roots naturally protect plants from the adverse effects of soil salinity by reprogramming the stress-induced physiological changes in plants. Bacteria can enrich the soil with major nutrients (nitrogen, phosphorus, and potassium) in a form easily available to plants and prevent the transport of excess sodium to roots (exopolysaccharides secreted by bacteria bind with sodium ions) for maintaining ionic balance and water potential in cells. Salinity also affects plant growth regulators and suppresses seed germination and root and shoot growth. Bacterial secretion of indole-3-acetic acid and gibberellins compensates for the salt-induced hormonal decrease in plants, and bacterial 1-aminocyclopropane-1-carboxylate (ACC) deaminase synthesis decreases ethylene production to stimulate plant growth. Furthermore, bacteria modulate the redox state of salinity-affected plants by enhancing antioxidants and polyamines, which leads to increased photosynthetic efficiency. Bacteria-induced accumulation of compatible solutes in stressed plants regulates plant cellular activities and prevents salt stress damage. Plant-bacterial interaction reprograms the expression of salt stress-responsive genes and proteins in salinity-affected plants, resulting in a precise stress mitigation metabolism as a defense mechanism. Soil bacteria increase the fertility of soil and regulate the plant functions to prevent the salinity effects in glycophytes. This review explains the current understanding about the physiological changes induced in glycophytes during bacterial interaction to alleviate the adverse effects of soil salinity stress. Copyright © 2017 Elsevier Masson SAS. All rights

Effect of inoculation with arbuscular mycorrhizas on rooting, weaning and subsequent growth of micropropagated Malus (L. Moench

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Marjatta Uosukainen

1994-05-01

Full Text Available The importance of different rooting methods and the effects of arbuscular mycorrhizal (AMF inoculation on the rooting rate, weaning survival and subsequent growth of microcuttings of Malus rootstock YP and the Finnish crab apple cultivars Hanna and Marjatta were studied in four experiments conducted at the Laukaa Research and Elite Plant Unit, Finland. Sucrose in the in vitro rooting medium gave the best support to weaning survival in comparision with glucose and fructose. Directly rooted microcuttings had a higher survival rate than in vitro rooted microcuttings. AMF inoculation did not improve the rooting rate in direct rooting. However, the Glomus hoi strain V98 caused severe rotting of microcuttings and thus lowered the rooting rate of cv. Hanna, AMF inoculation increased the mean shoot height of established plants, particularly inoculation with G. hoi V98, G. claroideum V43a or G. fistulosum V128. This effect, however, varied considerably in different host-fungus combinations. Some AMF strains, e.g. G. hoi V1O4, caused strong growth retardation. After the rooting and weaning stage, many uninoculated plants lapsed into arrest of growth. This phenomenon was less frequent in AMF inoculated plants. Optimal timing of AMF inoculation and nutritional level of rooting and weaning substrate are discussed.

Rhizosphere microbial communities from resistant and susceptible watermelon cultivars showed different response to fusarium oxysporum f. sp. niveum inoculation

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Zhi, W.F.; Can, C.S.; Ling, C.; Hui, X.W.

2015-01-01

Fusarium oxysporum f. sp. niveum (FON), a soil-borne pathogen of watermelon (Citrullus lanatus), can cause substantial production losses worldwide. In this study, plate culture and PCR-denaturing gradient gel electrophoresis (DGGE) methods were used to evaluate the effects of inoculation of Fusarium oxysporum f.sp. niveum on rhizosphere microbial communities of different watermelon cultivars to FON. Two methods indicated that the effects of watermelon rhizosphere microbial community of different resistance cultivars to FON were much different. Populations of culturable bacteria and actinomycetes in the rhizosphere of susceptible watermelon cultivar were significantly lower than in the resistant cultivar after inoculation (P<0.05), but the opposite result was observed for fungi. Principal component analysis of bacterial and fungal community structure also showed that the cultivar of FON-inoculated soil treatment were separated from the non-inoculated controls after inoculation, and there was clear discrimination between the susceptible cultivars and the resistant cultivars. Sequence analysis of specific bands from DGGE profiles showed that specific rhizosphere bacterial and fungal groups differed between watermelon cultivars after inoculation . Both methods demonstrated that different resistant watermelon cultivars occupied different rhizosphere microbial communities, and and disease suppression might be correlated with high microbial diversity. F. oxysporum f. sp. Niveum alters the structure and functional diversity of microbial communities associated with watermelon rhizosphere. (author)

Effect of bacterial contamination on the incorporation of radioactive phosphate in plant r-RNA

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Koleva, S; Khanymova, T; Marinova, E; Varadinova, S

1974-01-01

It is ascertained that the amount of bacterial colonies in root tips of maize seedlings (Wisconsin 641 AA) constitutes approximately 4.5x10/sup 7/ per gram of fresh weight, 90% of the bacterial colonies being various pseudomonas. In the case when plant RNA is labelled with /sup 32/P, the bacteria take up a large amount of phosphate. Owing to this, the RNA isolated from the root tips and fractionated in agar gel, in addition to 25S and 18S r-RNA of the plant cell cytoplasma contains also 23S and 16S of the bacterial r-RNA. Chloramphenicol at a concentration of 50/cm/sup 3/ does not suppress the incorporation of /sup 32/P by the bacteria. The pseudomonas strains isolated are almost insensitive to chloramphenicol and a number of other antibiotics, such as penicyllin, erythromycin, neomycin and oxacylin. This results, as well as the results, obtained by other researchers, indicate that antibiotics do not suppress effectively the action of bacterial contamination if plant RNA is labelled. Furtheremore, some of them, as streptomycin, for instance, if employed at higher concentrations inhibit the growth of the plant cell. Of all asceptic agents (hypochlorite, ethanol, sulphuric acid, etc.), used for surface sterilization, best results in the elimination of bacterial infection on maize seeds have been obtained with 0.1% HgCl/sub 2/ after treatment for 2 min. In spite of the elimination of the bacterial contamination with HgCl/sub 2/,the RNA from the elongated cells, labelled with /sup 32/P for an hour, is distributed into four fractions in the agar gel conversely to the RNA isolated from dividing cells, where only the two 25S and 18S fractions of plant cytoplasmic r-RNA are observed. An assumption is made that the two more fast-moving r-RNA fractions, as compared with 25S and 18S of plant r-RNA, isolated from elongating cells, originate from subcellular organelles, since the mitochondria and the proplstids are fully differentiated during the phase of the elongation of the

Inoculation method could impact the outcome of microbiological experiments

DEFF Research Database (Denmark)

Kragh, Kasper Nørskov; Alhede, Maria; Rybtke, Morten

2018-01-01

For the last 150 years, bacteria have primarily been investigated in liquid bacth cultures (LBC). Contrary to most expectations, these cultures are not a homogeneous mixture of single-celled bacteria as free-floating bacterial aggregates eventually develop in most LBC. These aggregates share...... coli and Staphylococcus aureus also produce aggregates in LBC. Our results stress the importance of inoculation consistency throughout experiments and the substantial impact aggregate development in LBC has on the output of microbiological experiments.IMPORTANCE Liquid pure cultures are fundamental...... to the field of microbiological research. These cultures are normally thought of as a homogeneous mix of single cell bacteria. The present study shows how this is not always true. Bacteria may aggregate in these liquid cultures. The aggregation can be induced by the method chosen for inoculation. The presence...

Effect of phosphate-solubilizing bacteria on phosphorus dynamics and the bacterial community during composting of sugarcane industry waste.

Science.gov (United States)

Estrada-Bonilla, German A; Lopes, Cintia M; Durrer, Ademir; Alves, Paulo R L; Passaglia, Nicolle; Cardoso, Elke J B N

2017-07-01

Sugarcane processing generates a large quantity of residues, such as filter cake and ashes, which are sometimes composted prior to their amendment in soil. However, important issues still have to be addressed on this subject, such as the description of bacterial succession that occurs throughout the composting process and the possibilities of using phosphate-solubilizing bacteria (PSB) during the process to improve phosphorus (P) availability in the compost end product. Consequently, this study evaluated the bacterial diversity and P dynamics during the composting process when inoculated with Pseudomonas aeruginosa PSBR12 and Bacillus sp. BACBR01. To characterize the bacterial community structure during composting, and to compare PSB-inoculated compost with non-inoculated compost, partial sequencing of the bacterial 16S rRNA gene and sequential P fractionation were used. The data indicated that members of the order Lactobacillales prevailed in the early stages of composting for up to 30 days, mostly due to initial changes in pH and the C/N ratio. This dominant bacterial group was then slowly replaced by Bacillales during a composting process of up to 60 days. In addition, inoculation of PSB reduced the levels of Ca-bound P by 21% and increased the labile organic P fraction. In PSB-inoculated compost, Ca-P compound solubilization occurred concomitantly with an increase of the genus Bacillus. The bacterial succession and the final community is described in compost from sugarcane residues and the possible use of these inoculants to improve P availability in the final compost is validated. Copyright © 2017 Elsevier GmbH. All rights reserved.

Biological Inoculants in Forage Conservation

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Judit Peter Szucs

2011-05-01

Full Text Available 3rd generation biological inoculants –containing lactic acid bacteria and enzymes – are prefered nowadays in order to coordinate the fermentation in such a way that they increase lactic acid production by leaps and bounds at the beginning of the fermentation and improve the quality and stability of silage during the fermentation and feeding. The quality of raw material (maturity of plant, chop lenght, spreading of inoculant uniformly and the proper filling, compacting, covering and wrapping have a great influence on the effectiveness of the inoculant. The mycotoxin content of malfermented silages is an undesirable risk factor. The authors established, that the Lactobacillus buchneri and enzymes containing inoculant protected better the carotene content of low, medium- and high wilteed lucerne haylages (P<0,05 compare to untreated ones Aerobic stability experiment by Honnig 1990 method was carried out with medium wilted (36 % DM lucerne haylage which was treatedtreated before ensilage with , the dosage of 105 CFU/g Pediococcus acidilactici, 1,5x105 CFU/g Lactobacillus buchneri and cellulase and hemicellulase enzimes (20 000 CMC /g remained stabyle, unspoiled after 9 days exposure to the air, while the untreated haylages spoiled after 2;4;or 7days on aerobic condition. The different Lactobacillus plantarum strains (50.000 CFU of Lactobacillus plantarum DSM 16568 + 50.000 CFU of Lactobacillus plantarum DSM 4784/ g FM of maize applied together were able to improve the aerobic stability of silomaize silage.

Application of hordothionins and cecropin B for engineering bacterial disease resistance into plants

NARCIS (Netherlands)

Florack, D.

1994-01-01

Bacterial diseases can cause a drastic decrease of yield in certain crops. Breeding for bacterial disease resistance therefore is of utmost necessity. Up to now, traditional plant breeding was the only method to reach this goal. Recent developments in genetic engineering technology however

Carbon nanomaterials alter plant physiology and soil bacterial community composition in a rice-soil-bacterial ecosystem.

Science.gov (United States)

Hao, Yi; Ma, Chuanxin; Zhang, Zetian; Song, Youhong; Cao, Weidong; Guo, Jing; Zhou, Guopeng; Rui, Yukui; Liu, Liming; Xing, Baoshan

2018-01-01

The aim of this study was to compare the toxicity effects of carbon nanomaterials (CNMs), namely fullerene (C 60 ), reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs), on a mini-ecosystem of rice grown in a loamy potted soil. We measured plant physiological and biochemical parameters and examined bacterial community composition in the CNMs-treated plant-soil system. After 30 days of exposure, all the three CNMs negatively affected the shoot height and root length of rice, significantly decreased root cortical cells diameter and resulted in shrinkage and deformation of cells, regardless of exposure doses (50 or 500 mg/kg). Additionally, at the high exposure dose of CNM, the concentrations of four phytohormones, including auxin, indoleacetic acid, brassinosteroid and gibberellin acid 4 in rice roots significantly increased as compared to the control. At the high exposure dose of MWCNTs and C 60 , activities of the antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD) in roots increased significantly. High-throughput sequencing showed that three typical CNMs had little effect on shifting the predominant soil bacterial species, but the presence of CNMs significantly altered the composition of the bacterial community. Our results indicate that different CNMs indeed resulted in environmental toxicity to rice and soil bacterial community in the rhizosphere and suggest that CNMs themselves and their incorporated products should be reasonably used to control their release/discharge into the environment to prevent their toxic effects on living organisms and the potential risks to food safety. Copyright © 2017 Elsevier Ltd. All rights reserved.

Defense reactions of bean genotypes to bacterial pathogens in controlled conditions

Science.gov (United States)

Uysal, B.; Bastas, K. K.

2018-03-01

This study was focused on the role of antioxidant enzymes and total protein in imparting resistance against common bacterial blight caused by Xanthomonas axonopodis pv. phaseoli (Xap) and halo blight caused by Pseudomonas syringae pv. phaseolicola (Psp) in bean. Activities of Ascorbate peroxidase (APX), Catalase (CAT) and total protein were studied in resistant and susceptible bean genotypes. Five-day-old seedlings were inoculated with a bacterial suspension (108 CFU ml-1) and harvested at different time intervals (0, 12, 24 and 36 up to 72 h) under controlled growing conditions and assayed for antioxidant enzymes and total protein. Temporal increase of CAT, APX enzymes activities showed maximum activity at 12 h after both pathogens inoculation (hpi) in resistant cultivar, whereas in susceptible it increased at 72 h after both pathogens inoculation for CAT and 12, 24 h for APX enzymes. Maximum total protein activities were observed at 12 h and 24 h respectively after Xap, Psp inoculation (hpi) in resistant and maximum activities were observed at 24 h and 72 h respectively after Xap, Psp inoculation (hpi) in susceptible. Increase of antioxidant enzyme and total protein activities might be an important component in the defense strategy of resistance and susceptible bean genotypes against the bacterial infection. These findings suggest that disease protection is proportional to the amount of enhanced CAT, APX enzyme and total protein activity.

Efecto de la inoculación de la cepa Sphingomonas paucimobilis 20006FA sobre la composición de un consorcio bacteriano degradador de fenantreno Effect of the inoculant strain Sphingomonas paucimobilis 20006FA on the bacterial composition of a phenanthrene-degrading consortium

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L. Madueño

2009-06-01

Full Text Available Se estudió el efecto de la inoculación con la cepa Sphingomonas paucimobilis 20006FA sobre la composición bacteriana de un consorcio degradador de fenantreno en cultivos discontinuos (batch con 8 repiques sucesivos. El consorcio original se obtuvo a partir de un suelo prístino. A los fines del estudio, se obtuvieron y mantuvieron dos consorcios: uno inoculado (F200+I y otro sin inocular (F200. Se estudió la diversidad bacteriana de los consorcios mediante el análisis de microorganismos cultivables (por caracterización fenotípica y genotípica y totales (por PCR-DGGE. A lo largo de los repiques sucesivos pudo observarse en ambos consorcios una tendencia a la pérdida de la capacidad degradadora de fenantreno, acompañada por una disminución de la diversidad bacteriana. Si bien la inoculación no produjo cambios significativos en la capacidad degradadora de fenantreno de los consorcios (29,9% para F200 y 27,6% para F200+I hacia el tercer repique, sí produjo cambios en la composición bacteriana, ya que los perfiles de DGGE revelaron una dinámica estructural diferente en el consorcio inoculado. En ambos consorcios se pudo observar la presencia de una banda intensa posicionada a la misma altura que el ADN del inóculo en el gel de DGGE; sin embargo, los cultivos aislados de los consorcios que presentaban idéntica posición de banda en el perfil PCR-DGGE que la cepa S. paucimobilis 20006FA mostraron baja similitud con la cepa inoculada mediante la técnica de RAPD.The effect of the inoculant strain Sphingomonas paucimobilis 20006FA on the bacterial composition of a phenanthrene-degrading consortium obtained from a pristine soil in sequencing batch cultures was studied. Inoculated (F200+I and non-inoculated (F200 phenanthrene-degrading consortia, were obtained. Bacterial diversity of consortia was studied at cultivable (phenotype and genotype characterization and non-cultivable (PCR-DGGE levels. During the successive cultures, a loss in

Bacterial disease management: challenges, experience, innovation and future prospects: Challenges in Bacterial Molecular Plant Pathology.

Science.gov (United States)

Sundin, George W; Castiblanco, Luisa F; Yuan, Xiaochen; Zeng, Quan; Yang, Ching-Hong

2016-12-01

Plant diseases caused by bacterial pathogens place major constraints on crop production and cause significant annual losses on a global scale. The attainment of consistent effective management of these diseases can be extremely difficult, and management potential is often affected by grower reliance on highly disease-susceptible cultivars because of consumer preferences, and by environmental conditions favouring pathogen development. New and emerging bacterial disease problems (e.g. zebra chip of potato) and established problems in new geographical regions (e.g. bacterial canker of kiwifruit in New Zealand) grab the headlines, but the list of bacterial disease problems with few effective management options is long. The ever-increasing global human population requires the continued stable production of a safe food supply with greater yields because of the shrinking areas of arable land. One major facet in the maintenance of the sustainability of crop production systems with predictable yields involves the identification and deployment of sustainable disease management solutions for bacterial diseases. In addition, the identification of novel management tactics has also come to the fore because of the increasing evolution of resistance to existing bactericides. A number of central research foci, involving basic research to identify critical pathogen targets for control, novel methodologies and methods of delivery, are emerging that will provide a strong basis for bacterial disease management into the future. Near-term solutions are desperately needed. Are there replacement materials for existing bactericides that can provide effective disease management under field conditions? Experience should inform the future. With prior knowledge of bactericide resistance issues evolving in pathogens, how will this affect the deployment of newer compounds and biological controls? Knowledge is critical. A comprehensive understanding of bacterial pathosystems is required to not

Salinity tolerance of Dodonaea viscosa L. inoculated with plant growth-promoting rhizobacteria: assessed based on seed germination and seedling growth characteristics

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Yousefi Sonia

2017-06-01

Full Text Available The study was conducted to evaluate the potential of different strains of plant growth-promoting rhizobacteria (PGPR to reduce the effects of salinity stress on the medicinal hopbush plant. The bacterium factor was applied at five levels (non-inoculated, inoculated by Pseudomonas putida, Azospirillum lipoferum + Pseudomonas putida, Azotobacter chroococcum + Pseudomonas putida, and Azospirillum lipoferum + Azotobacter chroococcum + Pseudomonas putida, and the salinity stress at six levels: 0, 5, 10, 15, 20, and 50 dS m-1. The results revealed that Pseudomonas putida showed maximal germination percentage and rate at 20 dS m-1 (18.33% and 0.35 seed per day, respectively. The strongest effect among the treatments was obtained with the treatment combining the given 3 bacteria at 15 dS m-1 salinity stress. This treatment increased the root fresh and dry weights by 31% and 87.5%, respectively (compared to the control. Our results indicate that these bacteria applied on hopbush affected positively both its germination and root growth. The plant compatibility with the three bacteria was found good, and the treatments combining Pseudomonas putida with the other one or two bacteria discussed in this study can be applied in nurseries in order to restore and extend the area of hopbush forests and akin dry stands.

Nitrogen translocation in wheat inoculated with Azospirillum and fertilized with nitrogen

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RODRIGUES OSMAR

2000-01-01

Full Text Available The productivity and the translocation of assimilates and nitrogen (N were compared after inoculation of wheat (Triticum aestivum L., cv. BR-23 seeds with two strains of Azospirillum brasilense (strains 245 and JA 04 under field conditions. The inoculation of wheat seeds was done with a peat inoculant at sowing time. Plant material for evaluations were collected at anthesis and maturity. No differences in grain yield and in the translocation of assimilates resulting from inoculation were detected. Differences were observed in relation to N rates (0, 15, and 60 kg ha-1. N content in the grain increased significantly in the bacteria-inoculated treatments in which N was not added. This increase in N content in the grain with inoculation was probably due to higher N uptake after anthesis without any significant contribution on the grain yield. Such increment was of 8.4 kg ha-1 of N representing 66% more N than in no inoculated treatment. Regardless of the inoculation and the rate of N applied, it was observed that about 70% of the N accumulated at anthesis was translocated from vegetative parts to the grain.

Nutritional and fermentation parameters of Xaraés grass silage produced with bacterial additive

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Erickson Tiago Pinheiro da Silva

2014-07-01

Full Text Available The use of bacterial additives in forage silages with low content of dry matter prevents undesirable fermentation and reduces losses by gases (PG and effluents (PE during the ensiling process. This study aimed to evaluate the fermentation parameters, chemical composition and in vitro digestibility of silage of Urochloa brizantha cv. Xaraés produced with bacterial additive. The inoculant contained the following strains: Propionibacterium acidipropionici + Lactobacillus plantarum; Lactobacillus buchnari; Propionibacterium acipropionici + commercial enzymes and Lactobacillus plantarum and Pediococcus pentosaccus, at 0, 25, 50, 75, 100, and 125% of the recommended level for sugarcane (2 g ton-1. The experiment was a completely randomized design with four replications, and six levels of inoculant (0, 25, 50, 75, 100, and 125%. There was a quadratic relationship between the inoculant addition and the levels of pH, PE, DMIVD, NDF, ADF and LIG of the silage. PG and MM increased linearly with the addition of inoculant. The N-NH3, DM, CP, CEL, HEM and EE were not affected by the inoculant. Bacterial additive at 50% provided increased DMIVD. Appropriate values were found for pH and NH3.

Transgenic plants producing the bacterial pheromone N-acyl-homoserine lactone exhibit enhanced resistance to the bacterial phytopathogen Erwinia carotovora.

Science.gov (United States)

Mäe, A; Montesano, M; Koiv, V; Palva, E T

2001-09-01

Bacterial pheromones, mainly different homoserine lactones, are central to a number of bacterial signaling processes, including those involved in plant pathogenicity. We previously demonstrated that N-oxoacyl-homoserine lactone (OHL) is essential for quorum sensing in the soft-rot phytopathogen Erwinia carotovora. In this pathogen, OHL controls the coordinate activation of genes encoding the main virulence determinants, extracellular plant cell wall degrading enzymes (PCWDEs), in a cell density-dependent manner. We suggest that E. carotovora employ quorum sensing to avoid the premature production of PCWDEs and subsequent activation of plant defense responses. To test whether modulating this sensory system would affect the outcome of a plant-pathogen interaction, we generated transgenic tobacco, producing OHL. This was accomplished by ectopic expression in tobacco of the E. carotovora gene expI, which is responsible for OHL biosynthesis. We show that expI-positive transgenic tobacco lines produced the active pheromone and partially complemented the avirulent phenotype of expI mutants. The OHL-producing tobacco lines exhibited enhanced resistance to infection by wild-type E. carotovora. The results were confirmed by exogenous addition of OHL to wild-type plants, which also resulted in increased resistance to E. carotovora.

Inoculation with arbuscular mycorrhizae does not improve 137Cs uptake in crops grown in the Chernobyl region

International Nuclear Information System (INIS)

Vinichuk, M.; Mårtensson, A.; Rosén, K.

2013-01-01

Methods for cleaning up radioactive contaminated soils are urgently needed. In this study we investigated whether the use of arbuscular mycorrhizal (AM) fungi can improve 137 Cs uptake by crops. Barley, cucumber, perennial ryegrass, and sunflower were inoculated with AM fungi and grown in low-level radionuclide contaminated soils in a field experiment 70 km southwest of Chernobyl, Ukraine, during two successive years (2009–2010). Roots of barley, cucumber and sunflower plants were slightly or moderately infected with AM fungus and root infection frequency was negatively or non-correlated with 137 Cs uptake by plants. Roots of ryegrass were moderately infected with AM fungus and infection frequency was moderately correlated with 137 Cs uptake by ryegrass. The application of AM fungi to soil in situ did not enhance radionuclide plant uptake or biomass. The responsiveness of host plants and AM fungus combination to 137 Cs uptake varied depending on the soil, although mycorrhization of soil in the field was conditional and did not facilitate the uptake of radiocesium. The total amount of 137 Cs uptake by plants growing on inoculated soil was equal to amounts in plant cultivated on non-inoculated soil. Thus, the use of AM fungi in situ for bioremediation of soil contaminated with a low concentration of 137 Cs could not be recommended. -- Highlights: • Effect of mycorrhization on 137 Cs uptake by crops was studied in a field experiment. • AM fungi did not enhance radionuclide plant uptake or biomass. • Plants growing on inoculated and non-inoculated soil accumulate 137 Cs equally

Bacterial microflora characteristics of plant samples from contaminated by radionuclides Chernobyl area

International Nuclear Information System (INIS)

Zelena, Pavlina; Shevchenko, Julia; Molozhava, Olha; Berezhna, Valentina; Shylina, Julia; Guscha, Mykola

2015-01-01

Two serious nuclear accidents during the last quarter century (Chernobyl, 1986 and Fukushima, 2011) contaminated large agricultural areas with radioactivity. In radioactive areas all components of ecosystems, including microorganisms, exposed to ionizing radiation. The aim of this study was isolation and identification of dominant bacteria from plant samples, which were collected from the area of radioactive contamination and to compare it with bacteria isolated from plant collected in a non-radioactive area by their qualitative composition, physiological, biochemical and pathogenic characteristics. Bacteria were isolated from plant samples grown in a radioactive field located 5 km from the Chernobyl Nuclear Power Plant (CNPP). Physiological, biochemical and pathogenic properties were characterized from nine pure bacterial isolates. The common features of bacteria from radionuclide contaminated plant samples were increased synthesis of mucus and capsule creation. It was found that all selected isolates produce catalase, therefore, bacteria were resistant to oxidative stress. The increased pathogenicity of most bacteria isolated from the plant grown in radioactive Chernobyl area compare to the isolates from the plant without radioactive contamination was established from the phytopathogenic tests. Consequently, bacterial isolates from the plants grown in the radioactive environment tends to dominate enterobacteria similar to agents of opportunistic infections. (author)

Co-inoculation with Rhizobium and plant growth promoting rhizobacteria (PGPR for inducing salinity tolerance in mung bean under field condition of semi arid climate

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Muhammad Aamir

2013-04-01

Full Text Available Salinity stress severely affects the growth, nodulation and yield of mung bean (Vigna radiata L.. However, its growth can be improved under salinity stress by inoculation/co-inoculation with rhizobia and plant growth promoting rhizobacteria (PGPR containing 1-Aminocyclopropane-1-carboxylic acid (ACC deaminase enzyme. ACC-deaminase containing bacteria regulate the stress induced ethylene production by hydrolyzing the ACC (immediate precursor of ethylene into ammonia and ketobutyric acid, thus improve plant growth by lowering the ethylene level. A study was conducted under salt affected field conditions where pre-isolated strains of Rhizobium and PGPR were used alone as well as in combination for mitigating the salinity stress on growth, nodulation and yield of mung bean by following the randomized complete block design (RCBD. The data were recorded and analyzed statistically to see the difference among treatments.

Variations in early response of grapevine wood depending on wound and inoculation combinations with Phaeoacremonium aleophilum and Phaeomoniella chlamydospora

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Romain J. G. PIERRON

2016-03-01

Full Text Available Defense mechanisms in woody tissue are poorly understood, especially in vine colonized by trunk pathogens. However, several investigations suggest that molecular mechanisms in the central tissue of Vitis vinifera L. may be involved in trunk-defense reactions. In this work, the perception of Phaeoacremonium aleophilum and Phaeomoniella chlamydospora alone or together were investigated in cuttings of Cabernet Sauvignon trunks. Plant responses were analyzed at the tissue level via optical microscopy and at the cellular level via plant-gene expression. The microscopy results revealed that, six weeks after pathogen inoculation, newly formed vascular tissue is less developed in plants inoculated with P. chlamydospora than in plants inoculated with P. aleophilum. Co-inoculation with both pathogens resulted in an intermediate phenotype. Further analysis showed the relative expression of the following grapevine genes: PAL, PR10.3, TL, TLb, Vv17.3, STS, STS8, CWinv, PIN, CAM, LOX at 10, 24, 48, and 120 h post-inoculation (hpi. The gene set was induced by wounding before inoculation with the different pathogens, except for the genes CAM and LOX. This response generated significant noise, but the expression of the grapevine genes (PAL, PR10.3, TL, TLb, Vv17.3, STS, STS8, CWinv, and PIN still differed due to perception of mycelium by the plant. Furthermore, at 48 hpi, the induction of PAL and STS8 differs depending on the pathogen, and a specific pattern emerges from the different inductions associated with the different treatments. Based on these results, we conclude that Vitis vinifera L. trunk perceives the presence of pathogens differently depending on the inoculated pathogen or even on the combination of co-inoculated pathogens, suggesting a defense orchestration in the perennial organs of woody plants.

Effects of inoculating Lachnum and Cadophora isolates on the growth of Vaccinium corymbosum.

Science.gov (United States)

Bizabani, Christine; Dames, Joanna

2015-12-01

The roots of ericaceous plants harbour a diversity of fungal taxa, which confer eco-physiological benefits to the host. Some of the fungi have been established to form ericoid mycorrhizal (ERM) associations and enhance plant growth in certain ericaceous genera. Although, Lachnum and Cadophora isolates have frequently been identified from the roots of this family, the status of their association and functional roles is still vague. The aims of this study were to identify Lachnum and Cadophora isolates; determine the root-fungal interactive structures formed in associations with Vaccinium corymbosum L. (blueberry) hosts and to examine inoculation effects of the fungal associates using several varieties of the blueberry. Lachnum and Cadophora were isolated and identified from Erica cerinthoides L. and Erica demmissa Klotzsch ex Benth using morphological and molecular techniques. Micropropagated blueberry varieties (Bluecrop, Elliott, Spartan, Chandler and Brightwell) were inoculated with respective fungi and plant growth evaluated. Both fungi colonised the roots and did not have any pathogenic effect. Lachnum isolate did not form any particular mycorrhizal structures whereas; Cadophora inoculated plants showed typical ericoid mycorrhizal coils. Inoculation with both fungi enhanced the shoot growth of Brightwell and Elliott varieties. However neutral effects were observed in the remaining varieties. In conclusion, Cadophora and Lachnum isolates have potential to promote growth of selected blueberry varieties. Copyright © 2015 Elsevier GmbH. All rights reserved.

Inoculation of the nonlegume Capsicum annuum L. with Rhizobium strains. 2. Changes in sterols, triterpenes, fatty acids, and volatile compounds.

Science.gov (United States)

Silva, Luís R; Azevedo, Jessica; Pereira, Maria J; Carro, Lorena; Velazquez, Encarna; Peix, Alvaro; Valentão, Patrícia; Andrade, Paula B

2014-01-22

Peppers (Capsicum spp.) are consumed worldwide, imparting flavor, aroma, and color to foods, additionally containing high concentrations of biofunctional compounds. This is the first report about the effect of the inoculation of two Rhizobium strains on sterols, triterpenes, fatty acids, and volatile compounds of leaves and fruits of pepper (Capsicum annuum L.) plants. Generally, inoculation with strain TVP08 led to the major changes, being observed a decrease of sterols and triterpenes and an increase of fatty acids, which are related to higher biomass, growth, and ripening of pepper fruits. The increase of volatile compounds may reflect the elicitation of plant defense after inoculation, since the content on methyl salicylate was significantly increased in inoculated material. The findings suggest that inoculation with Rhizobium strains may be employed to manipulate the content of interesting metabolites in pepper leaves and fruits, increasing potential health benefits and defense abilities of inoculated plants.

Impact of soil salinity on the plant-growth – promoting and biological control abilities of root associated bacteria

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Dilfuza Egamberdieva

2017-11-01

Full Text Available The effectiveness of plant growth – promoting bacteria is variable under different biotic and abiotic conditions. Abiotic factors may negatively affect the beneficial properties and efficiency of the introduced PGPR inoculants. The aim of this study was to evaluate the effect of plant growth – promoting rhizobacteria on plant growth and on the control of foot and root rot of tomatoes caused by Fusarium solani under different soil salinity conditions. Among the five tested strains, only Pseudomonas chlororaphis TSAU13, and Pseudomonas extremorientalis TSAU20 were able to stimulate plant growth and act as biological controls of foot and root rot disease of tomato. The soil salinity did not negatively affect the beneficial impacts of these strains, as they were able to colonize and survive on the roots of tomato plants under both saline and non-saline soil conditions. The improved plant height and fruit yield of tomato was also observed for plants inoculated with P. extremorientalis TSAU20. Our results indicated that, saline condition is not crucial factor in obtaining good performance with respect to the plant growth stimulating and biocontrol abilities of PGPR strains. The bacterial inoculant also enhanced antioxidant enzymes activities thereby preventing ROS induced oxidative damage in plants, and the proline concentrations in plant tissue that play an important role in plant stress tolerance.

Plant water stress effects on stylet probing behaviors of Homalodisca vitripennis (Hemiptera: Cicadellidae) associated with acquisition and inoculation of the bacterium Xylella fastidiosa.

Science.gov (United States)

Krugner, Rodrigo; Backus, Elaine A

2014-02-01

ABSTRACT The glassy-winged sharpshooter, Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), is a xylem fluid-ingesting leafhopper that transmits Xylella fastidiosa Wells et al., a plant-infecting bacterium that causes several plant diseases in the Americas. Although the role of plant water stress on the population density and dispersal ofH. vitripennis has been studied, nothing is known about the effects of plant water stress on the transmission of X. fastidiosa by H. vitripennis. A laboratory study was conducted to determine the influence of plant water stress on the sharpshooter stylet probing behaviors associated with the acquisition and inoculation of X. fastidiosa. Electrical penetration graph was used to monitor H. vitripennis feeding behaviors for 20-h periods on citrus [Citrus sinensis (L.) Osbeck] and almond [Prunus dulcis (Miller) D.A. Webb] plants subjected to levels of water stress. Adult H. vitripennis successfully located xylem vessels, then performed behaviors related to the evaluation of the xylem cell and fluid, and finally ingested xylem fluid from citrus and almond plants under the tested fluid tensions ranging from -5.5 to -33.0 bars and -6.0 to -24.5 bars, respectively. In general, long and frequent feeding events associated with the acquisition and inoculation of X. fastidiosa were observed only in fully irrigated plants (i.e., >-10 bars), which suggests that even low levels of plant water stress may reduce the spread of X. fastidiosa. Results provided insights to disease epidemiology and support the hypothesis that application of regulated deficit irrigation has the potential to reduce the incidence of diseases caused by X.fastidiosa by reducing the number of vectors and by decreasing pathogen transmission efficiency.

Effects of Pseudomonas putida and Glomusintraradices Inoculations on Morphological and Biochemical Traitsin Trigonellafoenum-graecum L.

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simin irankhah

2017-02-01

Full Text Available Introduction: Fenugreek (Trigonellafoenum-graecum L. is a traditional medicinal plant belonging to the legume family Fabaceae. Diverse groups of microorganisms are symbiotic with Fenugreek roots system. This integration leads to significant increases in the development and production by increasing nitrogen fixation, phytohormones production, siderophores and phosphate solubilization. Plant growth-promoting bacteria increase plant growth byimproving nutrientuptake and phytohormones production. In addition, the beneficial effect of these bacteria could be due totheirinteractionwithArbuscularMycorrhizal fungi(VAM. Drought is one of the major limiting factors for crop production in many parts of the world including Iran. Symbiotic microorganisms can enhance plant tolerance to drought. This experiment was carried out to investigate the effect of Vesicular ArbuscularMycorrhiza (VAM and Plant Growth Promoting Rhizobacteria (PGPR on morphological and biochemical characteristics of Fenugreek in drought stress conditions. Materials and Methods: The experiment was carried out in completely random design with 3 replications.There were four treatments including inoculation with Pseudomonas putida, inoculation with Glomusintraradices, combined association of Pseudomonas putida and Glomusintraradices and untreated as a check under drought stress (40% of field capacity and non-stress conditions (80% of field capacity. In this experiment fiveseeds were sowninplastic pots. Before sowing, seeds were inoculated with microorganisms. In order to inoculation ofseed with Mycorrhizal fungi, for each kilogram of soil, 100 grams of powder containing 10 to 15 thousand spores of fungal soil (produced by the biotech company Toos was added to three centimeters of soil in the pot. For seed inoculation with Plant Growth Promoting Rhizobacteria, the growth curve of the bacteria was drawn at first and then the best time for the growth of bacteria was determined. The bacteria at

Restructuring of Endophytic Bacterial Communities in Grapevine Yellows-Diseased and Recovered Vitis vinifera L. Plants ▿

Science.gov (United States)

Bulgari, Daniela; Casati, Paola; Crepaldi, Paola; Daffonchio, Daniele; Quaglino, Fabio; Brusetti, Lorenzo; Bianco, Piero Attilio

2011-01-01

Length heterogeneity-PCR assays, combined with statistical analyses, highlighted that the endophytic bacterial community associated with healthy grapevines was characterized by a greater diversity than that present in diseased and recovered plants. The findings suggest that phytoplasmas can restructure the bacterial community by selecting endophytic strains that could elicit a plant defense response. PMID:21622794

A Bacterial Receptor PcrK Senses the Plant Hormone Cytokinin to Promote Adaptation to Oxidative Stress

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Fang-Fang Wang

2017-12-01

Full Text Available Summary: Recognition of the host plant is a prerequisite for infection by pathogenic bacteria. However, how bacterial cells sense plant-derived stimuli, especially chemicals that function in regulating plant development, remains completely unknown. Here, we have identified a membrane-bound histidine kinase of the phytopathogenic bacterium Xanthomonas campestris, PcrK, as a bacterial receptor that specifically detects the plant cytokinin 2-isopentenyladenine (2iP. 2iP binds to the extracytoplasmic region of PcrK to decrease its autokinase activity. Through a four-step phosphorelay, 2iP stimulation decreased the phosphorylation level of PcrR, the cognate response regulator of PcrK, to activate the phosphodiesterase activity of PcrR in degrading the second messenger 3′,5′-cyclic diguanylic acid. 2iP perception by the PcrK-PcrR remarkably improves bacterial tolerance to oxidative stress by regulating the transcription of 56 genes, including the virulence-associated TonB-dependent receptor gene ctrA. Our results reveal an evolutionarily conserved, inter-kingdom signaling by which phytopathogenic bacteria intercept a plant hormone signal to promote adaptation to oxidative stress. : How pathogenic bacteria use receptors to recognize the signals of the host plant is unknown. Wang et al. have identified a bacterial receptor histidine kinase that specifically senses the plant hormone cytokinin. Through a four-step phosphorelay, cytokinin perception triggers degradation of a second messenger, c-di-GMP, to activate the bacterial response to oxidative stress. Keywords: histidine kinase, ligand, cytokinin, autokinase activity, phosphorelay, response regulator, two-component signal transduction system, Xanthomonas campestris pv. campestris, virulence, oxidative stress

Modeling bacterial contamination of fuel ethanol fermentation.

Science.gov (United States)

Bischoff, Kenneth M; Liu, Siqing; Leathers, Timothy D; Worthington, Ronald E; Rich, Joseph O

2009-05-01

The emergence of antibiotic-resistant bacteria may limit the effectiveness of antibiotics to treat bacterial contamination in fuel ethanol plants, and therefore, new antibacterial intervention methods and tools to test their application are needed. Using shake-flask cultures of Saccharomyces cerevisiae grown on saccharified corn mash and strains of lactic acid bacteria isolated from a dry-grind ethanol facility, a simple model to simulate bacterial contamination and infection was developed. Challenging the model with 10(8) CFU/mL Lactobacillus fermentum decreased ethanol yield by 27% and increased residual glucose from 6.2 to 45.5 g/L. The magnitude of the effect was proportional to the initial bacterial load, with 10(5) CFU/mL L. fermentum still producing an 8% decrease in ethanol and a 3.2-fold increase in residual glucose. Infection was also dependent on the bacterial species used to challenge the fermentation, as neither L. delbrueckii ATCC 4797 nor L. amylovorus 0315-7B produced a significant decrease in ethanol when inoculated at a density of 10(8) CFU/mL. In the shake-flask model, treatment with 2 microg/mL virginiamycin mitigated the infection when challenged with a susceptible strain of L. fermentum (MIC for virginiamycin model may find application in developing new antibacterial agents and management practices for use in controlling contamination in the fuel ethanol industry. Copyright 2008 Wiley Periodicals, Inc.

Interspecific Plant Interactions Reflected in Soil Bacterial Community Structure and Nitrogen Cycling in Primary Succession.

Science.gov (United States)

Knelman, Joseph E; Graham, Emily B; Prevéy, Janet S; Robeson, Michael S; Kelly, Patrick; Hood, Eran; Schmidt, Steve K

2018-01-01

Past research demonstrating the importance plant-microbe interactions as drivers of ecosystem succession has focused on how plants condition soil microbial communities, impacting subsequent plant performance and plant community assembly. These studies, however, largely treat microbial communities as a black box. In this study, we sought to examine how emblematic shifts from early successional Alnus viridus ssp. sinuata (Sitka alder) to late successional Picea sitchensis (Sitka spruce) in primary succession may be reflected in specific belowground changes in bacterial community structure and nitrogen cycling related to the interaction of these two plants. We examined early successional alder-conditioned soils in a glacial forefield to delineate how alders alter the soil microbial community with increasing dominance. Further, we assessed the impact of late-successional spruce plants on these early successional alder-conditioned microbiomes and related nitrogen cycling through a leachate addition microcosm experiment. We show how increasingly abundant alder select for particular bacterial taxa. Additionally, we found that spruce leachate significantly alters the composition of these microbial communities in large part by driving declines in taxa that are enriched by alder, including bacterial symbionts. We found these effects to be spruce specific, beyond a general leachate effect. Our work also demonstrates a unique influence of spruce on ammonium availability. Such insights bolster theory relating the importance of plant-microbe interactions with late-successional plants and interspecific plant interactions more generally.

Comparative studies about fungal colonization and deoxynivalenol translocation in barley plants inoculated at the base with Fusarium graminearum, Fusarium culmorum and Fusarium pseudograminearum

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Francesco Pecoraro

2018-03-01

Full Text Available Fusarium crown rot (FCR, an important disease of wheat and barley, is mainly caused by Fusarium graminearum, F. culmorum and F. pseudograminearum, which are also responsible for mycotoxin production. This is the first comparative investigation of their colonization on barley plants after stem base inoculation. At plant maturity, FCR symptoms were visually evaluated, fungal biomass was quantified by Real-Time quantitative PCR and deoxynivalenol (DON was detected by enzyme-linked immunosorbent assay (ELISA. All the inoculated strains caused the typical FCR necrotic symptoms. Real-Time PCR analysis showed that F. graminearum and F. culmorum were present in the head tissues, while F. pseudograminearum colonized only up to the area including the second node of the stem. Conversely, DON was detected up to the head for all the three species. This study shows that, as already demonstrated in previous research for wheat, DON may be detected up to the head as a consequence of stem base infection by the three FCR agents

Bacterial anoxygenic photosynthesis on plant leaf surfaces.

Science.gov (United States)

Atamna-Ismaeel, Nof; Finkel, Omri; Glaser, Fabian; von Mering, Christian; Vorholt, Julia A; Koblížek, Michal; Belkin, Shimshon; Béjà, Oded

2012-04-01

The aerial surface of plants, the phyllosphere, is colonized by numerous bacteria displaying diverse metabolic properties that enable their survival in this specific habitat. Recently, we reported on the presence of microbial rhodopsin harbouring bacteria on the top of leaf surfaces. Here, we report on the presence of additional bacterial populations capable of harvesting light as a means of supplementing their metabolic requirements. An analysis of six phyllosphere metagenomes revealed the presence of a diverse community of anoxygenic phototrophic bacteria, including the previously reported methylobacteria, as well as other known and unknown phototrophs. The presence of anoxygenic phototrophic bacteria was also confirmed in situ by infrared epifluorescence microscopy. The microscopic enumeration correlated with estimates based on metagenomic analyses, confirming both the presence and high abundance of these microorganisms in the phyllosphere. Our data suggest that the phyllosphere contains a phylogenetically diverse assemblage of phototrophic species, including some yet undescribed bacterial clades that appear to be phyllosphere-unique. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

nfluences of ammonium-nitrate, food waste compost and bacterial fertilizer on soluble soil nitrogen forms and on the growth of carrot (Daucus Carota L.

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Andrea Balla Kovács

2014-04-01

Full Text Available This paper reports a greenhouse study to compare the effects of food waste compost, bacterial fertilizer and their combination with the effect of mineral fertilizer on yield of carrot and the available nutrient content of soils. The study was conducted on calcareous chernozem and acidic sandy soils and consisted of 8 treatments in a randomized complete block design with four replications. The NH4NO3 resulted in reduced growing of carrot plant in sandy soil, and the treatment effect of mineral fertilizer was not observed significantly in chernozem soil. Sandy soil showed higher response of growth of carrot to food waste compost fertilization than chernozem soil. Sole application of EM-1 bacterial fertilizer did not have marked effect on yield parameters and sizes of roots. When EM-1 bacterial fertilizer was applied together with ammonium-nitrate or with compost in chernozem soil, the weights of roots and the sizes of roots in some cases became higher compared to the values of appropriate treatments without inoculation. In sandy soil the diameter of roots slightly increased when EM-1 bacterial fertilizer was applied with ammonium-nitrate and with ammonium-nitrate+compost combination compared to appropriate treatment without inoculation. In chernozem soil the maximum weights and sizes of roots were achieved with the combined treatment of ammonium-nitrate+compost+EM-1 bacterial fertilizer and in sandy soil with compost treatment. Our results of soluble nitrogen content of soils are in good agreement with yield parameters of carrot. Results suggest that food waste compost could be a good substitute for mineral fertilizer application in carrot production mainly in sandy soil. EM-1 bacterial fertilizer did not cause marked effect on yield and yield parameters of carrot plant, but its combination with other fertilizers promises a little bit higher yield or plant available nutrient in the soil. These effects do not clear exactly, so further studies are

Increased acidification in the rhizosphere of cactus seedlings induced by Azospirillum brasilense

Science.gov (United States)

Carrillo, Angel; Li, Ching; Bashan, Yoav

2002-08-01

Acidification of the rhizosphere of cactus seedlings (giant cardon, Pachycereus pringlei) after inoculation with the plant growth-promoting bacterium Azospirillum brasilense Cd, in the presence or absence of ammonium and nitrate, was studied to understand how to increase growth of cardon seedlings in poor desert soils. While ammonium enhanced rhizosphere and liquid culture acidification, inoculation with the bacteria enhanced it further. On the other hand, nitrate increased pH of the rhizosphere, but combined with the bacterial inoculation, increase in pH was significantly smaller. Bacterial inoculation with ammonium enhanced plant growth.

Wild plant species growing closely connected in a subalpine meadow host distinct root-associated bacterial communities

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Kristin Aleklett

2015-02-01

Full Text Available Plant roots are known to harbor large and diverse communities of bacteria. It has been suggested that plant identity can structure these root-associated communities, but few studies have specifically assessed how the composition of root microbiota varies within and between plant species growing under natural conditions. We assessed the community composition of endophytic and epiphytic bacteria through high throughput sequencing using 16S rDNA derived from root tissues collected from a population of a wild, clonal plant (Orange hawkweed–Pilosella aurantiaca as well as two neighboring plant species (Oxeye daisy–Leucanthemum vulgare and Alsike clover–Trifolium hybridum. Our first goal was to determine if plant species growing in close proximity, under similar environmental conditions, still hosted unique root microbiota. Our results showed that plants of different species host distinct bacterial communities in their roots. In terms of community composition, Betaproteobacteria (especially the family Oxalobacteraceae were found to dominate in the root microbiota of L. vulgare and T. hybridum samples, whereas the root microbiota of P. aurantiaca had a more heterogeneous distribution of bacterial abundances where Gammaproteobacteria and Acidobacteria occupied a larger portion of the community. We also explored the extent of individual variance within each plant species investigated, and found that in the plant species thought to have the least genetic variance among individuals (P. aurantiaca still hosted just as diverse microbial communities. Whether all plant species host their own distinct root microbiota and plants more closely related to each other share more similar bacterial communities still remains to be fully explored, but among the plants examined in this experiment there was no trend that the two species belonging to the same family shared more similarities in terms of bacterial community composition.

Differential oxidative and antioxidative response of duckweed Lemna minor toward plant growth promoting/inhibiting bacteria.

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Ishizawa, Hidehiro; Kuroda, Masashi; Morikawa, Masaaki; Ike, Michihiko

2017-09-01

Bacteria colonizing the plant rhizosphere are believed to positively or negatively affect the host plant productivity. This feature has inspired researchers to engineer such interactions to enhance crop production. However, it remains to be elucidated whether rhizobacteria influences plant oxidative stress vis-a-vis other environmental stressors, and whether such influence is associated with their growth promoting/inhibiting ability. In this study, two plant growth-promoting bacteria (PGPB) and two plant growth-inhibiting bacteria (PGIB) were separately inoculated into axenic duckweed (Lemna minor) culture under laboratory conditions for 4 and 8 days in order to investigate their effects on plant oxidative stress and antioxidant activities. As previously characterized, the inoculation of PGPB and PGIB strains accelerated and reduced the growth of L. minor, respectively. After 4 and 8 days of cultivation, compared to the PGPB strains, the PGIB strains induced larger amounts of O 2 •- , H 2 O 2 , and malondialdehyde (MDA) in duckweed, although all bacterial strains consistently increased O 2 •- content by two times more than that in the aseptic control plants. Activities of five antioxidant enzymes were also elevated by the inoculation of PGIB, confirming the severe oxidative stress condition in plants. These results suggest that the surface attached bacteria affect differently on host oxidative stress and its response, which degree correlates negatively to their effects on plant growth. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Screening and characterization of endophytic Bacillus and Paenibacillus strains from medicinal plant Lonicera japonica for use as potential plant growth promoters

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Longfei Zhao

2015-12-01

Full Text Available Abstract A total of 48 endophytic bacteria were isolated from surface-sterilized tissues of the medicinal plant Lonicera japonica, which is grown in eastern China; six strains were selected for further study based on their potential ability to promote plant growth in vitro (siderophore and indoleacetic acid production. The bacteria were characterized by phylogenetically analyzing their 16S rRNA gene similarity, by examining their effect on the mycelial development of pathogenic fungi, by testing their potential plant growth-promoting characteristics, and by measuring wheat growth parameters after inoculation. Results showed that the number of endophytic bacteria in L. japonica varied among different tissues, but it remained relatively stable in the same tissues from four different plantation locations. Among the three endophytic strains, strains 122 and 124 both had high siderophore production, with the latter showing the highest phosphate solubilization activity (45.6 mg/L and aminocyclopropane-1-carboxylic acid deaminase activity (47.3 nmol/mg/h. Strain 170 had the highest indoleacetic acid (IAA production (49.2 mg/L and cellulase and pectinase activities. After inoculation, most of the six selected isolates showed a strong capacity to promote wheat growth. Compared with the controls, the increase in the shoot length, root length, fresh weight, dry weight, and chlorophyll content was most remarkable in wheat seedlings inoculated with strain 130. The positive correlation between enzyme (cellulose and pectinase activity and inhibition rate on Fusarium oxysporum, the IAA production, and the root length of wheat seedlings inoculated with each tested endophytic strain was significant in regression analysis. Deformity of pathogenic fungal mycelia was observed under a microscope after the interaction with the endophytic isolates. Such deformity may be directly related to the production of hydrolytic bacterial enzymes (cellulose and pectinase. The six

Bacterial Rhizosphere Biodiversity from Several Pioneer Desert Sand Plants Near Jizan, Saudi Arabia

KAUST Repository

Osman, Jorge R.; Zelicourt, Axel de; Bisseling, Ton; Geurts, Rene; Hirt, Heribert; DuBow, Michael S.

2016-01-01

Life in arid regions and, in particular, hot deserts is often limited due to their harsh environmental conditions, such as large temperature fluctuations and low amounts of water. These extreme environments can influence the microbial community present on the surface sands and any rhizosphere members surrounding desert plant roots. The Jizan desert area, located in Saudi Arabia, supports particular vegetation that grows in the large sandy flat terrain. We examined five different samples, four from the rhizosphere of pioneer plants plus a surface sand sample, and used pyrosequencing of PCR-amplified V1-V3 regions of 16S rDNA genes from total extracted DNA to reveal and compare the bacterial population diversity of the samples. The results showed a total of 3,530 OTUs in the five samples, calculated using ≥ 97% sequence similarity levels. The Chao1 estimation of the bacterial diversity fluctuated from 637 to 2,026 OTUs for a given sample. The most abundant members found in the samples belong to the Bacteroidetes, Firmicutes and Proteobacteria phyla. This work shows that the Jizan desert area of Saudi Arabia can contain a diverse bacterial community on the sand and surrounding the roots of pioneer desert plants. It also shows that desert sand microbiomes can vary depending on conditions, with broad implications for sandstone monument bacterial communities

Bacterial Rhizosphere Biodiversity from Several Pioneer Desert Sand Plants Near Jizan, Saudi Arabia

KAUST Repository

Osman, Jorge R.

2016-04-08

Life in arid regions and, in particular, hot deserts is often limited due to their harsh environmental conditions, such as large temperature fluctuations and low amounts of water. These extreme environments can influence the microbial community present on the surface sands and any rhizosphere members surrounding desert plant roots. The Jizan desert area, located in Saudi Arabia, supports particular vegetation that grows in the large sandy flat terrain. We examined five different samples, four from the rhizosphere of pioneer plants plus a surface sand sample, and used pyrosequencing of PCR-amplified V1-V3 regions of 16S rDNA genes from total extracted DNA to reveal and compare the bacterial population diversity of the samples. The results showed a total of 3,530 OTUs in the five samples, calculated using ≥ 97% sequence similarity levels. The Chao1 estimation of the bacterial diversity fluctuated from 637 to 2,026 OTUs for a given sample. The most abundant members found in the samples belong to the Bacteroidetes, Firmicutes and Proteobacteria phyla. This work shows that the Jizan desert area of Saudi Arabia can contain a diverse bacterial community on the sand and surrounding the roots of pioneer desert plants. It also shows that desert sand microbiomes can vary depending on conditions, with broad implications for sandstone monument bacterial communities

Soil microbial species loss affects plant biomass and survival of an introduced bacterial strain, but not inducible plant defences

NARCIS (Netherlands)

Kurm, Viola; Putten, Van Der Wim H.; Pineda, Ana; Hol, G.W.H.

2018-01-01

• Background and Aims: Plant growth-promoting rhizobacteria (PGPR) strains can influence plant-insect interactions. However, little is known about the effect of changes in the soil bacterial community in general and especially the loss of rare soil microbes on these interactions. Here, the influence

Inoculating wheat (Triticum aestivum L.) with the endophytic bacterium Serratia sp. PW7 to reduce pyrene contamination.

Science.gov (United States)

Zhu, Xuezhu; Wang, Wanqing; Sun, Kai; Lin, Xianghao; Li, Shuang; Waigi, Michael Gatheru; Ling, Wanting

2017-08-03

This research was conducted to find an optimal inoculation way for a pyrene-degrading endophytic Serratia sp. PW7 to colonize wheat for reducing pyrene contamination. Three inoculation ways, which are soaking seeds in inocula (TS), dipping roots of seedlings in inocula (TR), and spraying inocula on leaves of seedlings (TL), were used in this study. Inoculated seedlings and noninoculated seedlings (CK) were, respectively, cultivated in Hoagland solutions supplemented with pyrene in a growth chamber. The results showed that strain PW7 successfully colonized the inoculated seedlings in high numbers, and significantly promoted the growth of seedlings (TS and TR). More importantly, strain PW7 reduced pyrene levels in the seedlings and the Hoagland solutions. Compared to the noninoculated seedlings, the pyrene contents of the inoculated seedlings were decreased by 35.7-86.3% in the shoots and by 26.8-60.1% in the roots after 8-day cultivation. By comparing the efficiencies of decreasing pyrene residues, it can be concluded that TR was an optimal inoculation way for endophytic strains to colonize the inoculated plants and to reduce the pyrene contamination. Our findings provide an optimized inoculation way to reduce organic contamination in crops by inoculating plants with functional endophytic bacteria.

Effects of Rhizobuim leguminosarum inoculation on the growth and ...

African Journals Online (AJOL)

g per plant in 2008 and 2009 seasons, respectively. The findings suggested that inoculation of Mucuna flagellipies with Rhizobium is beneficial and produced high seed yield and could be use as biofertilizer an alternative to nitrogen fertilizer.

[Inoculation experiments of Cistanche tubulosa on 8 introduced Tamarix species].

Science.gov (United States)

Yang, Tai-Xin; Lu, Yue-Xia; Zhang, Xi-Huan; Cai, Jing-Zhu; Zhao, Yu-Xin

2007-10-01

To analyze the inoculation ratio and echinacoside content of Cistanche tubulosa and provide theoretical basis for Tamarix introduction, resource protection and screening of C. tubulosa. 8 Tamarix species were introduced in the North China Plain and inoculation of C. tubulosa was conducted on all species. Phenylethanoid glycosides fingerprinting and echinacoside content of C. tubulosa were analyzed by using HPLC. The adaptability of 8 Tamarix species were significantly different, phenylethanoid glycosides component of C. tubulosa on T. gansuensis and T. austromongolica were basically identical in contrast to T. chinensis, echinacoside content showed no obvious difference in C. tubulosa plant growing 4 months. T. gansuensis and T. Austromongolica are suitable for the host introduction plant of C. tubulosa resource protection and screening in North China Plain.

Paenibacillus lentimorbus Inoculation Enhances Tobacco Growth and Extenuates the Virulence of Cucumber mosaic virus.

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Susheel Kumar

Full Text Available Previous studies with Paenibacillus lentimorbus B-30488" (hereafter referred as B-30488, a plant growth promoting rhizobacteria (PGPR isolated from cow's milk, revealed its capabilities to improve plant quality under normal and stress conditions. Present study investigates its potential as a biocontrol agent against an economically important virus, Cucumber mosaic virus (CMV, in Nicotiana tabacum cv. White Burley plants and delineates the physical, biophysical, biochemical and molecular perturbations due to the trilateral interactions of PGPR-host-CMV. Soil inoculation of B-30488 enhanced the plant vigor while significantly decreased the virulence and virus RNA accumulation by ~12 fold (91% in systemic leaves of CMV infected tobacco plants as compared to the control ones. Histology of these leaves revealed the improved tissue's health and least aging signs in B-30488 inoculated tobacco plants, with or without CMV infection, and showed lesser intercellular spaces between collenchyma cells, reduced amount of xyloglucans and pectins in connecting primary cells, and higher polyphenol accumulation in hypodermis layer extending to collenchyma cells. B-30488 inoculation has favorably maneuvered the essential biophysical (ion leakage and photosynthetic efficiency and biochemical (sugar, proline, chlorophyll, malondialdehyde, acid phosphatase and alkaline phosphatase attributes of tobacco plants to positively regulate and release the virus stress. Moreover, activities of defense related enzymes (ascorbate peroxidase, guaiacol peroxidase, superoxide dismutase and catalase induced due to CMV-infection were ameliorated with inoculation of B-30488, suggesting systemic induced resistance mediated protection against CMV in tobacco. The quantitative RT-PCR analyses of the genes related to normal plant development, stress and pathogenesis also corroborate well with the biochemical data and revealed the regulation (either up or down of these genes in favor of

Phytomanagement of Cd-contaminated soils using maize (Zea mays L.) assisted by plant growth-promoting rhizobacteria.

Science.gov (United States)

Moreira, Helena; Marques, Ana P G C; Franco, Albina R; Rangel, António O S S; Castro, Paula M L

2014-01-01

Zea mays (L.) is a crop widely cultivated throughout the world and can be considered suitable for phytomanagement due to its metal resistance and energetic value. In this study, the effect of two plant growth-promoting rhizobacteria, Ralstonia eutropha and Chryseobacterium humi, on growth and metal uptake of Z. mays plants in soils contaminated with up to 30 mg Cd kg(-1) was evaluated. Bacterial inoculation increased plant biomass up to 63% and led to a decrease of up to 81% in Cd shoot levels (4-88 mg Cd kg(-1)) and to an increase of up to 186% in accumulation in the roots (52-134 mg Cd kg(-1)). The rhizosphere community structure changed throughout the experiment and varied with different levels of Cd soil contamination, as revealed by molecular biology techniques. Z. mays plants inoculated with either of the tested strains may have potential application in a strategy of soil remediation, in particular short-term phytostabilization, coupled with biomass production for energy purposes.

The decrease in the population of Gluconacetobacter diazotrophicus in sugarcane after nitrogen fertilization is related to plant physiology in split root experiments.

Science.gov (United States)

Rodríguez-Andrade, Osvaldo; Fuentes-Ramírez, Luis E; Morales-García, Yolanda E; Molina-Romero, Dalia; Bustillos-Cristales, María R; Martínez-Contreras, Rebeca D; Muñoz-Rojas, Jesús

2015-01-01

It has been established that a decrease in the population of Gluconacetobacter diazotrophicus associated with sugarcane occurs after nitrogen fertilization. This fact could be due to a direct influence of NH(4)NO(3) on bacterial cells or to changes in plant physiology after fertilizer addition, affecting bacterial establishment. In this work, we observed that survival of G. diazotrophicus was directly influenced when 44.8mM of NH(4)NO(3) (640mgN/plant) was used for in vitro experiments. Furthermore, micropropagated sugarcane plantlets were inoculated with G. diazotrophicus and used for split root experiments, in which both ends of the system were fertilized with a basal level of NH(4)NO(3) (0.35mM; 10mgN/plant). Twenty days post inoculation (dpi) one half of the plants were fertilized with a high dose of NH(4)NO(3) (6.3mM; 180 mgN/plant) on one end of the system. This nitrogen level was lower than that directly affecting G. diazotrophicus cells; however, it caused a decrease in the bacterial population in comparison with control plants fertilized with basal nitrogen levels. The decrease in the population of G. diazotrophicus was higher in pots fertilized with a basal nitrogen level when compared with the corresponding end supplied with high levels of NH4NO3 (100dpi; 80 days post fertilization) of the same plant system. These observations suggest that the high nitrogen level added to the plants induce systemic physiological changes that affect the establishment of G. diazotrophicus. Copyright © 2015 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Effect of mycorrhizal inoculation on the growth and phytoextraction of heavy metals by maize grown in oil contaminated soil

International Nuclear Information System (INIS)

Achakzai, A.K.K.; Liasu, M.O.; Popoola, O.J.

2011-01-01

Pot experiments were conducted to investigate the effect of AM (Glomus mosseae ) fungi inoculation (M) on the growth of maize and phyto extraction of selected heavy metals from a soil contaminated with crude oil (C). Four soil treatments, each with three replicates i.e., C/sup +/M/sup +/, M/sup +/, C/sup +/ and control (without oil and inoculum) were conducted. Half of the pots with the soil treatments were planted with singly sown (SS) and the other half with densely sown i.e., four maize seedlings (DS). Various plant growth attributes were measured at weekly intervals Cu/sup 2+/, Ni/sup 2+/, Pb/sup 2+/ and Cd/sup 2+/ in the soil, root and shoot of maize plants were determined separately. Inoculation by AM promoted the vegetative growth attributes in both treatments viz., C/sup +/M/sup +/ and M/+. AM inoculation also promoted the hyper extraction of heavy metals from C/sup +/M/sup +/ soils, but inhibited by soils treated with M/sup +/. High planting density i.e., DS also promoted phyto extraction of heavy metals from uncontaminated (M/sup +/) soils, but had minimal effect on phyto extraction from oil contaminated soils (C/sup +/). Planting density complemented the promotive effect of AM inoculation on phyto extraction of heavy metals from C/sup +/ soils. The hyper extraction of selected metals from soil is more favored by planting density in C/sup +/ soils, whereas AM inoculation tends to exclude heavy metals from potted plants. However, in case of C/sup +/M/sup +/ soils, AM inoculation promotes the hyper extraction of metals more than planting density. While the combination of the two phenomena act synergistically to promote metal hyper extraction from C/sup +/M/sup +/ as well as M/sup +/ soils. (author)

Bacterial adaptation to the gut environment favors successful colonization: microbial and metabonomic characterization of a simplified microbiota mouse model.

Science.gov (United States)

Rezzonico, Enea; Mestdagh, Renaud; Delley, Michèle; Combremont, Séverine; Dumas, Marc-Emmanuel; Holmes, Elaine; Nicholson, Jeremy; Bibiloni, Rodrigo

2011-01-01

Rodent models harboring a simple yet functional human intestinal microbiota provide a valuable tool to study the relationships between mammals and their bacterial inhabitants. In this study, we aimed to develop a simplified gnotobiotic mouse model containing 10 easy-to-grow bacteria, readily available from culture repositories, and of known genome sequence, that overall reflect the dominant commensal bacterial makeup found in adult human feces. We observed that merely inoculating a mix of fresh bacterial cultures into ex-germ free mice did not guarantee a successful intestinal colonization of the entire bacterial set, as mice inoculated simultaneously with all strains only harbored 3 after 21 d. Therefore, several inoculation procedures were tested and levels of individual strains were quantified using molecular tools. Best results were obtained by inoculating single bacterial strains into individual animals followed by an interval of two weeks before allowing the animals to socialize to exchange their commensal microbes. Through this procedure, animals were colonized with almost the complete bacterial set (9/10). Differences in the intestinal composition were also reflected in the urine and plasma metabolic profiles, where changes in lipids, SCFA, and amino acids were observed. We conclude that adaptation of bacterial strains to the host's gut environment (mono-colonization) may predict a successful establishment of a more complex microbiota in rodents.

An in vitro model to study interactions between Escherichia coli and lactic acid bacterial inoculants for silage in rumen fluid.

Science.gov (United States)

Weinberg, Z G; Chen, Y; Volchinski, V; Sela, S; Ogunade, I M; Adesogan, A

2016-07-01

Previous studies have shown that silages treated with lactic acid bacteria (LAB) inoculants enhance ruminants' performance. The objective of the current experiments was to develop an in vitro model to study interactions between LAB silage inoculants and inoculated silages and Escherichia coli (EC) in rumen fluid (RF). Our hypothesis was that some inoculants inhibit EC in RF. For that purpose buffered RF was incubated under anaerobic conditions at 39°C with commercial strains of LAB silage inoculants or with laboratory corn and wheat silages treated with these LAB, an EC strain and with various ruminant feed ingredients. The EC strain was originally isolated from cattle manure and tagged with a plasmid expressing the green fluorescence protein and kanamycin and streptomycin resistance. Results indicate that the LAB or the treated silages did not suppress EC numbers in the RF. When the pH of the RF decreased below 5·0 the EC disappeared. We conclude that both LAB inoculants for silage and EC survived in RF for several days; however, the inoculants and silages treated with such inoculants did not inhibit EC in RF in vitro. Forage crops, silage and hay are initial stages of the food chain for humans. Cattle harbours and sheds enterobacteria regularly, some strains of which are pathogens. These can contaminate forage crops through field fertilization with cattle manure. The objective of this study was to develop an in vitro model to test whether lactic acid bacteria, which are used in silage inoculants, alone or in treated silages can inhibit Escherichia coli in rumen fluid. This study presents safety aspects and it is also part of a broad research effort aimed at finding out how LAB silage inoculants and inoculated silages enhance ruminant performance or exert probiotic effects in ruminants. © 2016 The Society for Applied Microbiology.

Tiller density and tillering on Brachiaria brizantha cv. Marandu pastures inoculated with Azospirillum brasilense

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B.C. Pedreira

Full Text Available ABSTRACT The objective of this study is to verify the population density and the dynamics of tillering in the Marandu palisade grass sward subjected to nitrogen (N fertilization strategies, characterized by the N supply via urea or bacterial inoculant (Azospirillum brasilense. The treatments comprised of four nitrogen fertilization strategies: (A Without fertilization, (B 80 kg N/ha, (C inoculant (A. brasilense, and (D 80 kg N/ha + inoculant, distributed in a randomized complete block design, with three replications. The nitrogen supply strategies were evaluated during six periods: October, November, and December (2012 as well as January, March, and April (2013. The nitrogen dose or inoculant had no effect on the tiller appearance rate (TAR, tiller mortality rate (TMR, tiller survival rate (TSR, or tiller population density (TPD. However, these variables were influenced by the season. The TAR and TSR were higher at the beginning of the experimental period (October and lower towards the end of the period (March-April, whereas, TMR and TPD exhibited the opposite behavior, with lower values in October and higher from January onward. Neither the nitrogen nor the inoculant influenced the population dynamics of the tillers in Marandu palisade grass.

BACTERIAL POPULATION DYNAMICS IN WASTE OILY EMULSIONS FROM THE METAL-PROCESSING INDUSTRY

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Paweł Kaszycki

2014-07-01

Full Text Available Oil-containing wastewaters are regarded as main industrial pollutants of soil and water environments. They can occur as free-floating oil, unstable or stable oil-in-water (O/W emulsions, and in the case of extreme organic load, as water-in-oil (W/O emulsions. In this study two types of oily effluents, a typical O/W emulsion marked as E1 and a W/O emulsion E2, both discharged by local metal processing plants were examined to test their toxicity to microbial communities and the ability to serve as nutrient sources for bacterial growth. The organic contaminant load of the samples was evaluated on the basis of chemical oxygen demand (COD parameter values and was equal to 48 200 mg O2·dm-3 and >300 000 mg O2·dm-3 for E1 and E2, respectively.Both emulsions proved to be non toxic to bacterial communities and were shown to contain biodiverse autochthonous microflora consisting of several bacterial strains adapted to the presence of xenobiotics (the total of 1.36 · 106 CFU·cm-3 and 1.72 · 105 CFU·cm-3 was determined for E1 and E2, respectively. These indigenous bacteria as well as exogenously inoculated specialized allochthonous microorganisms were biostimulated so as to proliferate within the wastewater environment whose organic content served as the only source of carbon. The most favorable cultivation conditions were determined as fully aerobic growth at the temperature of 25 ºC. In 9 to 18 day-tests, autochthonous as well as bioaugmented allochthonous bacterial population dynamics were monitored. For both emulsions tested there was a dramatic increase (up to three orders of magnitude in bacterial frequency, as compared to the respective initial values. The resultant high biomass densities suggest that the effluents are susceptible to bioremediation. A preliminary xenobiotic biodegradation test confirmed that mixed auto- and allochthonous bacterial consortia obtained upon inoculation of the samples with microbiocenoses preselected for efficient

Bacterial community structure and variation in a full-scale seawater desalination plant for drinking water production

KAUST Repository

Belila, Abdelaziz

2016-02-18

Microbial processes inevitably play a role in membrane-based desalination plants, mainly recognized as membrane biofouling. We assessed the bacterial community structure and diversity during different treatment steps in a full-scale seawater desalination plant producing 40,000 m3/d of drinking water. Water samples were taken over the full treatment train consisting of chlorination, spruce media and cartridge filters, de-chlorination, first and second pass reverse osmosis (RO) membranes and final chlorine dosage for drinking water distribution. The water samples were analyzed for water quality parameters (total bacterial cell number, total organic carbon, conductivity, pH, etc.) and microbial community composition by 16S rRNA gene pyrosequencing. The planktonic microbial community was dominated by Proteobacteria (48.6%) followed by Bacteroidetes (15%), Firmicutes (9.3%) and Cyanobacteria (4.9%). During the pretreatment step, the spruce media filter did not impact the bacterial community composition dominated by Proteobacteria. In contrast, the RO and final chlorination treatment steps reduced the Proteobacterial relative abundance in the produced water where Firmicutes constituted the most dominant bacterial group. Shannon and Chao1 diversity indices showed that bacterial species richness and diversity decreased during the seawater desalination process. The two-stage RO filtration strongly reduced the water conductivity (>99%), TOC concentration (98.5%) and total bacterial cell number (>99%), albeit some bacterial DNA was found in the water after RO filtration. About 0.25% of the total bacterial operational taxonomic units (OTUs) were present in all stages of the desalination plant: the seawater, the RO permeates and the chlorinated drinking water, suggesting that these bacterial strains can survive in different environments such as high/low salt concentration and with/without residual disinfectant. These bacterial strains were not caused by contamination during

Endophytic bacterial effects on seed germination and mobilization of reserves in ammodendron biofolium

International Nuclear Information System (INIS)

Zhu, Y.; She, X.P.

2017-01-01

The main aim of this study was to analyze the mobilization of storage reserves during seed germination of Ammodendron bifolium by host plant-endophytic bacteria interaction and to determine the contribution of endophytic bacteria in plant establishment. The seeds were inoculated with three different endophytic bacteria from A. bifolium, Staphylococcus sp. AY3, Kocuria sp. AY9 and Bacillus sp. AG18, and they were germinated in the dark. Fresh weight changes and early seedling growth were assessed, and the content of storage compounds was quantified using biochemical assays in all germinated and non-germinated seeds. To understand the mechanism promoting seed germination, the activities of extracellular enzymes of bacterial isolates were also analyzed by the plate assay method. The results showed that treatment with endophytic bacteria accelerated seed germination; promoted further water absorption and radicle growth; and also promoted degradation of sucrose, protein and lipids during the germination process. At the same time, our results also showed that strain AG18 was able to produce protease and amylase, strain AY9 had only amylase activity, and strain AY3 had no extracellular enzyme activity. In summary, our current study showed that (i) endophytic bacteria improved seed germination and post-germination seedling growth of A. bifolium; (ii) inoculation with endophytic bacteria could promote storage reserve mobilization during or following germination; (iii) the degradation of protein, lipids and sucrose could provide essential energy for post-germination growth; and (iv) three bacterial isolates might have different action mechanisms on seed germination. (author)

Bacterial Community Structure Shifted by Geosmin in Granular Activated Carbon System of Water Treatment Plants.

Science.gov (United States)

Pham, Ngoc Dung; Lee, Eun-Hee; Chae, Seon-Ha; Cho, Yongdeok; Shin, Hyejin; Son, Ahjeong

2016-01-01

We investigated the relation between the presence of geosmin in water and the bacterial community structure within the granular activated carbon (GAC) system of water treatment plants in South Korea. GAC samples were collected in May and August of 2014 at three water treatment plants (Sungnam, Koyang, and Yeoncho in Korea). Dissolved organic carbon and geosmin were analyzed before and after GAC treatment. Geosmin was found in raw water from Sungnam and Koyang water treatment plants but not in that from Yeoncho water treatment plant. Interestingly, but not surprisingly, the 16S rRNA clone library indicated that the bacterial communities from the Sungnam and Koyang GAC systems were closely related to geosmin-degrading bacteria. Based on the phylogenetic tree and multidimensional scaling plot, bacterial clones from GAC under the influence of geosmin were clustered with Variovorax paradoxus strain DB 9b and Comamonas sp. DB mg. In other words, the presence of geosmin in water might have inevitably contributed to the growth of geosmin degraders within the respective GAC system.

Interaction of rhizosphere bacteria, fertilizer, and vesicular-arbuscular mycorrhizal fungi with sea oats.

Science.gov (United States)

Will, M E; Sylvia, D M

1990-07-01

Plants must be established quickly on replenished beaches in order to stabilize the sand and begin the dune-building process. The objective of this research was to determine whether inoculation of sea oats (Uniola paniculata L.) with bacteria (indigenous rhizosphere bacteria and N(2) fixers) alone or in combination with vesicular-arbuscular mycorrhizal fungi would enhance plant growth in beach sand. At two fertilizer-N levels, Klebsiella pneumoniae and two Azospirillum spp. did not provide the plants with fixed atmospheric N; however, K. pneumoniae increased root and shoot growth. When a sparingly soluble P source (CaHPO(4)) was added to two sands, K. pneumoniae increased plant growth in sand with a high P content. The phosphorus content of shoots was not affected by bacterial inoculation, indicating that a mechanism other than bacterially enhanced P availability to plants was responsible for the growth increases. When sea oats were inoculated with either K. pneumoniae or Acaligenes denitrificans and a mixed Glomus inoculum, there was no consistent evidence of a synergistic effect on plant growth. Nonetheless, bacterial inoculation increased root colonization by vesicular-arbuscular mycorrhizal fungi when the fungal inoculum consisted of colonized roots but had no effect on colonization when the inoculum consisted of spores alone. K. pneumoniae was found to increase spore germination and hyphal growth of Glomus deserticola compared with the control. The use of bacterial inoculants to enhance establishment of pioneer dune plants warrants further study.