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Sample records for bacterial inoculation plant

  1. Resistance Induction and Enhanced Tuber Production by Pre-inoculation with Bacterial Strains in Potato Plants against Phytophthora infestans

    OpenAIRE

    Kim, Hyo-Jeong; Jeun, Yong-Chull

    2006-01-01

    Efficacy of resistance induction by the bacterial isolates Pseudomonas putida (TRL2-3), Micrococcus luteus (TRK2-2) and Flexibacteraceae bacterium (MRL412), which were isolated from the rhizosphere of plants growing in Jeju Mountain, were tested in a greenhouse. The disease severity caused by Phytophthora infestans was effectively reduced in the potato plants pre-inoculated with bacterial isolates compared with those of the untreated control plants growing in a greenhouse. In order to estimat...

  2. Klebsiella pneumoniae inoculants for enhancing plant growth

    Science.gov (United States)

    Triplett, Eric W.; Kaeppler, Shawn M.; Chelius, Marisa K.

    2008-07-01

    A biological inoculant for enhancing the growth of plants is disclosed. The inoculant includes the bacterial strains Herbaspirillum seropedicae 2A, Pantoea agglomerans P101, Pantoea agglomerans P102, Klebsiella pneumoniae 342, Klebsiella pneumoniae zmvsy, Herbaspirillum seropedicae Z152, Gluconacetobacter diazotrophicus PA15, with or without a carrier. The inoculant also includes strains of the bacterium Pantoea agglomerans and K. pneumoniae which are able to enhance the growth of cereal grasses. Also disclosed are the novel bacterial strains Herbaspirillum seropedicae 2A, Pantoea agglomerans P101 and P102, and Klebsiella pneumoniae 342 and zmvsy.

  3. 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

  4. Enhanced Degradation of Diesel in the Rhizosphere of after Inoculation with Diesel-Degrading and Plant Growth-Promoting Bacterial Strains.

    Science.gov (United States)

    Balseiro-Romero, María; Gkorezis, Panagiotis; Kidd, Petra S; Vangronsveld, Jaco; Monterroso, Carmen

    2016-05-01

    The association of plants and rhizospheric bacteria provides a successful strategy to clean up contaminated soils. The purpose of this work was to enhance diesel degradation in rhizosphere by inoculation with selected bacterial strains: a diesel degrader (D), plant growth-promoting (PGP) strains, or a combination (D+PGP). Plants were set up in pots with the A or B horizon of an umbric Cambisol (A and B) spiked with diesel (1.25%, w/w). After 1 mo, the dissipation of diesel range organics (DRO) with respect to = 0 (i.e., 1 wk after preparing the pots with the seedlings) concentration was significantly higher in inoculated than in noninoculated (NI) pots: The highest DRO losses were found in A D+PGP pots (close to 15-20% higher than NI) and in B D pots (close to 10% higher). The water-extractable DRO fraction was significantly higher at = 30 d (15-25%) compared with = 0 (PGP strains resulted in a promising combination for application in the rhizoremediation of soils with moderate diesel contamination. PMID:27136159

  5. Plant growth-promoting bacteria as inoculants in agricultural soils

    Directory of Open Access Journals (Sweden)

    Rocheli de Souza

    2015-01-01

    Full Text Available AbstractPlant-microbe interactions in the rhizosphere are the determinants of plant health, productivity and soil fertility. Plant growth-promoting bacteria (PGPB are bacteria that can enhance plant growth and protect plants from disease and abiotic stresses through a wide variety of mechanisms; those that establish close associations with plants, such as the endophytes, could be more successful in plant growth promotion. Several important bacterial characteristics, such as biological nitrogen fixation, phosphate solubilization, ACC deaminase activity, and production of siderophores and phytohormones, can be assessed as plant growth promotion (PGP traits. Bacterial inoculants can contribute to increase agronomic efficiency by reducing production costs and environmental pollution, once the use of chemical fertilizers can be reduced or eliminated if the inoculants are efficient. For bacterial inoculants to obtain success in improving plant growth and productivity, several processes involved can influence the efficiency of inoculation, as for example the exudation by plant roots, the bacterial colonization in the roots, and soil health. This review presents an overview of the importance of soil-plant-microbe interactions to the development of efficient inoculants, once PGPB are extensively studied microorganisms, representing a very diverse group of easily accessible beneficial bacteria.

  6. Plant growth-promoting bacteria as inoculants in agricultural soils.

    Science.gov (United States)

    Souza, Rocheli de; Ambrosini, Adriana; Passaglia, Luciane M P

    2015-12-01

    Plant-microbe interactions in the rhizosphere are the determinants of plant health, productivity and soil fertility. Plant growth-promoting bacteria (PGPB) are bacteria that can enhance plant growth and protect plants from disease and abiotic stresses through a wide variety of mechanisms; those that establish close associations with plants, such as the endophytes, could be more successful in plant growth promotion. Several important bacterial characteristics, such as biological nitrogen fixation, phosphate solubilization, ACC deaminase activity, and production of siderophores and phytohormones, can be assessed as plant growth promotion (PGP) traits. Bacterial inoculants can contribute to increase agronomic efficiency by reducing production costs and environmental pollution, once the use of chemical fertilizers can be reduced or eliminated if the inoculants are efficient. For bacterial inoculants to obtain success in improving plant growth and productivity, several processes involved can influence the efficiency of inoculation, as for example the exudation by plant roots, the bacterial colonization in the roots, and soil health. This review presents an overview of the importance of soil-plant-microbe interactions to the development of efficient inoculants, once PGPB are extensively studied microorganisms, representing a very diverse group of easily accessible beneficial bacteria. PMID:26537605

  7. Stable cesium uptake and accumulation capacities of five plant species as influenced by bacterial inoculation and cesium distribution in the soil.

    Science.gov (United States)

    Djedidi, Salem; Kojima, Katsuhiro; Yamaya, Hiroko; Ohkama-Ohtsu, Naoko; Bellingrath-Kimura, Sonoko Dorothea; Watanabe, Izumi; Yokoyama, Tadashi

    2014-09-01

    The effects of inoculation with Bacillus and Azospirillum strains on growth and cesium accumulation of five plant species, Komatsuna, Amaranth, sorghum, common millet and buckwheat, grown on cesium-spiked soil were assessed for potential use in cesium remediation. Pot experiments were performed using "artificially" Cs-contaminated soil. Three treatments were applied based on Cs location in the soil. For a soil height of 15 cm in the pots, Cs was added as follows: in the top five cm to imitate no ploughing condition; in the bottom five cm simulating inverted ploughing; and uniformly distributed Cs reproducing normal plowing. Generally, inoculation of Cs-exposed plants significantly enhanced growth and tolerance to this element. Transfer factor (ratio of Cs concentration in the plant tissues to that in surrounding soil) was strongly influenced by Cs distribution, with higher values in the top-Cs treatment. Within this treatment, inoculation of Komatsuna with Bacillus and Azospirillum strains resulted in the greatest transfer factors of 6.55 and 6.68, respectively. Cesium content in the shoots was high in the Azospirillum-inoculated Komatsuna, Amaranth, and buckwheat, i.e., 1,830, 1,220, and 1,030 µg per pot, respectively (five plants were grown in each pot). Therefore, inoculation of Komatsuna and Amaranth with the strains tested here could be effective in enhancing Cs accumulation. The decrease of Cs transfer under uniform- and bottom-Cs treatments would suggest that countermeasures aiming at decreasing the transfer of Cs could rely on ploughing practices. PMID:25002227

  8. Inoculation with Phosphate-Solubilizing Fungi Diversifies the Bacterial Community in Rhizospheres of Maize and Soybean

    Institute of Scientific and Technical Information of China (English)

    WANG Guang-Hua; JIN Jian; XU Mei-Na; PAN Xiang-Wen; G.TANG

    2007-01-01

    Application of phosphate-solubilizing microorganisms(PSMs)has been reported to increase P uptake and plant growth.However,no information is available regarding the ecological consequences of the inoculation with PSMs.The effect of inoculation with phosphate-solubilizing fungal(PSF)isolates Aspergillus niger P39 and Penicillium oxalicumreaction-denaturing gradient gel electrophoresis(PCR-DGGE).Compared with the control,the number of culturable microbes for soybean Was significantly greater with P39,whereas for maize,the same Was significantly greater with P66.In addition,a greater number of microbes were fouud in the rhizosphere of maize compared with soybean.The fingerprint of DGGE for 16S rDNA indicated that inoculation with PSF also increased bacterial communities,with the P66 treatment having higher numbers of DGGE bands and a higher Shannon-Weaver diversity index compared with P39;the composition of the microbial community was also more complex with the P66 treatment.Overall,complex interactions between plant species and exotic PSMs affected the structure of the bacterial community in the rhizosphere.but plant species were more important in determining the bacterial community structure than the introduction of exotic microorganisms.

  9. Response of rice to inoculation with plant growth promoting rhizobacteria in control lab environment and field experiment

    International Nuclear Information System (INIS)

    The present study was conducted to evaluate the effects of bacterial inoculation on different growth parameters of rice variety JP-5. Three bacterial strains (Azospirillum brasilense R1, Azospirillum lipoferum RSWT1 and Pseudomonas Ky1) were used to inoculate rice varietyJP-5 at control lab environment and field. Plant growth promotion was observed in all inoculated treatments over non-inoculated, which was evident from increase in root area, root length, number of tillers, straw and grain yields and total weight of plant. Azospirillum brasilense R1 was more effective in plant growth promotion than other strains and showed 19% increase in the straw weight and 39.5% increase in grain weight. Inoculation with Azospirillum lipoferum RSWT1 and Pseudomonas Ky1 increased grain weight by 18.5% and 13.8% respectively. The study revealed that beneficial strains of PGPR can be used as biofertilizer for rice. (author)

  10. Key factors to inoculate Botrytis cinerea in tomato plants

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    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.

  11. Plant yield and nitrogen content of a digitgrass in response to azospirillum inoculation

    Energy Technology Data Exchange (ETDEWEB)

    Schank, S.C.; Weier, K.L.; MacRae, I.C.

    1981-02-01

    Two Australian soils, a vertisol (pH 6.8, 0.299% N) and a sandy yellow podzol (pH 6.2, 0.042% N), were used with digitgrass, Digitaria sp. X46-2 (PI 421785), in a growth room experiment. Comparisons were made between plants inoculated with live and autoclaved bacterial suspensions of Australian and Brazilian isolates of Azospirillum brasilense. Seedlings were inoculated on days 10 and 35. Acetylene-reducing activity was measured five times during the experiment. Dry matter yields of the digitgrass on the podzol (low N) inoculated with liver bacteria were 23% higher than those of the controls. On the vertisol (high N), yield increases from inoculation with live bacteria were 8.5%. The higher-yielding plants had significantly lower precent nitrogen, but when total nitrogen of the tops was calculated, the inoculated plants had a higher total N than did the controls (P = 0.04). Acetylene-reducing activity was variable in the experiment, ranging from 0.5 to 11.9 mu mol of C2H2 core -1 day -1. Live bacterial treatment induced a proliferation of roots, possible earlier maturity, higher percent dry matter, and a higher total N in the tops. (Refs. 21).

  12. Evaluation of Varying Biochars as Carrier Materials for Bacterial Soil Inoculants

    Science.gov (United States)

    Hale, Lauren; Crowley, David

    2014-05-01

    The incorporation of biochar into agricultural soils for carbon sequestration and improved soil fertility creates an opportunity to simultaneously deliver plant-growth promoting rhizobacteria (PGPR). Many characteristics of biochar materials indicate that these particles could be conducive as inoculum carriers. This could provide a value-added component for biochar marketing and has an advantage over traditional carrier materials, which can be unsustainable or expensive to produce. Here, we assessed the suitability of 10 biochar types, made from 5 feedstocks at 2 pyrolysis temperatures (300°C and 600°C), to serve as carriers for 2 model PGPR strains, Enterobacter cloacae UW5 and Pseudomonas putida UW4. All biochars were characterized based on BET specific surface area, C-N content, pH, EC, and their abilities to adsorb bacterial cells from a liquid inoculum. Further studies incorporated qPCR to quantify the survival of inoculants after introduction into soils via biochar carriers. The biochars that performed well were further assayed for their influence on PGPR traits, 1-aminocyclopropane-1-carboxylate (ACC) deaminase and auxin production. Peat and vermiculite served as traditional carrier materials to which we compared the biochars. Our findings indicated that biochars varied in their interactions with our model PGPR strains. Based on our analysis several biochar types were able to serve as carriers which were as good, if not better than, the traditional carrier materials. Future work should seek to assess shelf life and varying inoculation methods for the biochar-inoculant complexes.

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

    International Nuclear Information System (INIS)

    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

  14. 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.

  15. Response of lupine plants irrigated with saline water to rhizobium inoculation using 15N-isotope dilution

    International Nuclear Information System (INIS)

    The lupine Rhizobium symbiosis and contribution of N2 fixation under different levels of irrigation water salinity were examined. Lysimeter experiment was established under greenhouse conditions during the year 2002-2003. In this experiment, inoculated plants were imposed to different salinity levels of irrigation water and N-fertilizer treatment. Plant height was decreased under different salinity levels, nitrogen treatments and bacterial inoculation. Similar trend was noticed with leaf area. The highest leaf area was recorded with salt tolerant bacterial inoculation (SBI) and splitting N-treatment. Highest values of N-uptake occurred after 100 day intervals under the tested factors. Relative decrease in N-uptake did not exceed 40% of those recorded with the fresh water treatment as affected by experimental factors. Nitrogen uptake by the whole plant reflected an increase at 3 dS/m salinity level of irrigation water. Relative increases were 5% and 15% for normal bacteria inoculation under single dose (NI) and splitting

  16. Comprehensive proteomic analysis of canola leaf inoculated with a plant growth-promoting bacterium, Pseudomonas fluorescens, under salt stress.

    Science.gov (United States)

    Banaei-Asl, Farzad; Farajzadeh, Davoud; Bandehagh, Ali; Komatsu, Setsuko

    2016-09-01

    Plant growth-promoting bacteria can improve the tolerance of canola to salt stress. To better understand the effects of plant growth-promoting bacterium on the protein profiles of canola under salt stress condition, proteomics was performed. Salt-sensitive (Sarigol) and -tolerant (Hyola308) canola cultivars were inoculated with Pseudomonas fluorescens FY32, and the protein profiles of canola leaves were compared using a PEG-fractionation method. Cluster analysis of canola cultivars based on a stress tolerance index of several morphological parameters was used to confirm that Sarigol and Hyola308 were salt-sensitive and -tolerant cultivars, respectively. Using a gel-free proteomic technique, 154 and 94 proteins in Hyola308 and 100 and 144 proteins in Sarigol were uniquely identified in non-inoculated and bacterial-inoculated cultivars, respectively. By PEG fractionation, a total of 132 and 207 proteins were identified in non-inoculated and inoculated Hyola308, respectively. Notably, the abundance of copper/zinc superoxide dismutase 1 was significantly increased in inoculated Hyola308 under severe salt stress and decreased under moderate salt stress. In addition, the enzyme activity of delta-1-pyrroline-5-carboxylate synthase was significantly increased non-inoculated Hyola308 and the activity of succinate dehydrogenase was increased in inoculated Hyola308 leaves exposed to salt stress. Taken together, these results suggest that the bacterial inoculation of canola increases salt tolerance by inducing an increase in the abundance of proteins related to glycolysis, tricarboxylic acid cycle, and amino acid metabolism. PMID:27137672

  17. Plant growth-promoting bacteria as inoculants in agricultural soils

    OpenAIRE

    Rocheli de Souza; Adriana Ambrosini; Passaglia, Luciane M. P.

    2015-01-01

    Abstract Plant-microbe interactions in the rhizosphere are the determinants of plant health, productivity and soil fertility. Plant growth-promoting bacteria (PGPB) are bacteria that can enhance plant growth and protect plants from disease and abiotic stresses through a wide variety of mechanisms; those that establish close associations with plants, such as the endophytes, could be more successful in plant growth promotion. Several important bacterial characteristics, such as biological nitro...

  18. 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. PMID:26873699

  19. Effect of isolate of ruminal fibrolytic bacterial culture supplementation on fibrolytic bacterial population and survivability of inoculated bacterial strain in lactating Murrah buffaloes

    Directory of Open Access Journals (Sweden)

    Brishketu Kumar

    2013-02-01

    Full Text Available Aim: The present study was conducted to evaluate the effect of bacterial culture supplementation on ruminal fibrolytic bacterial population as well as on survivability of inoculated bacterial strain in lactating Murrah buffaloes kept on high fibre diet. Materials and Methods: Fibrolytic bacterial strains were isolated from rumen liquor of fistulated Murrah buffaloes and live bacterial culture were supplemented orally in treatment group of lactating Murrah buffaloes fed on high fibre diet to see it's effect on ruminal fibrolytic bacterial population as well as to see the effect of survivability of the inoculated bacterial strain at three different time interval in comparison to control group. Results: It has been shown by real time quantification study that supplementation of bacterial culture orally increases the population of major fibre degrading bacteria i.e. Ruminococcus flavefaciens, Ruminococcus albus as well as Fibrobacter succinogenes whereas there was decrease in secondary fibre degrading bacterial population i.e. Butyrivibrio fibrisolvens over the different time periods. However, the inoculated strain of Ruminococcus flavefaciens survived significantly over the period of time, which was shown in stability of increased inoculated bacterial population. Conclusion: The isolates of fibrolytic bacterial strains are found to be useful in increasing the number of major ruminal fibre degrading bacteria in lactating buffaloes and may act as probiotic in large ruminants on fibre-based diets. [Vet World 2013; 6(1.000: 14-17

  20. Stability of chloroquine phosphate tablets inoculated with bacterial species

    International Nuclear Information System (INIS)

    Five popular brands of chloroquine tablets available to the average Nigerian consumers were examined for the effects of Staphylococcus aureus and Bacillus cereus, on the dissolution, disintegration and hardness after six weeks of incubation. The maximum percent dissolution was 98.34% with bacillus subtilis while the minimum was 19.12% with staphylococcus aureus. The disintegration results showed a maximum of 69 min. 19 sec with Staphylococcus aureus while the least was 56 sec with Bacillus subtilis. The maximum hardness obtained was 12.75 kg and the least was 1.25 kg also with Staphylococcus aureus. The dissolution, disintegration and hardness also varied with the control. The metabolic activities of the bacterial species were believed to have caused the variations in the physical properties of the chloroquine phosphate tablets. The results from this investigation strongly advises adequate storage of chloroquine phosphate tablets, especially when it is the drug of choice for the of sub-Saharan Africa. (author)

  1. Bacterial inoculants for enhanced seed germination of Spartina densiflora: Implications for restoration of metal polluted areas.

    Science.gov (United States)

    Paredes-Páliz, Karina I; Pajuelo, Eloísa; Doukkali, Bouchra; Caviedes, Miguel Ángel; Rodríguez-Llorente, Ignacio D; Mateos-Naranjo, Enrique

    2016-09-15

    The design of effective phytoremediation programs is severely hindered by poor seed germination on metal polluted soils. The possibility that inoculation with plant growth promoting rhizobacteria (PGPR) could help overcoming this problem is hypothesized. Our aim was investigating the role of PGPR in Spartina densiflora seed germination on sediments with different physicochemical characteristics and metal pollution degrees. Gram negative Pantoea agglomerans RSO6 and RSO7, and gram positive Bacillus aryabhattai RSO25, together with the consortium of the three strains, were used for independent inoculation experiments. The presence of metals (As, Cu, Pb and Zn) in sediments reduced seed germination by 80%. Inoculation with Bacillus aryabhattai RSO25 or Pantoea agglomerans RSO6 and RSO7 enhanced up to 2.5 fold the germination rate of S. densiflora in polluted sediments regarding non-inoculated controls. Moreover, the germination process was accelerated and the germination period was extended. The consortium did not achieve further improvements in seed germination. PMID:27315751

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

    Energy Technology Data Exchange (ETDEWEB)

    Sheng Xiafang [MOA Key Laboratory of Microbiological Engineering of Agricultural Environment, College of Life Science, Nanjing Agricultural University, Nanjing 210095 (China)], E-mail: xfsheng604@sohu.com; He Linyan; Wang Qingya; Ye Hesong; Jiang Chunyu [MOA Key Laboratory of Microbiological Engineering of Agricultural Environment, College of Life Science, Nanjing Agricultural University, Nanjing 210095 (China)

    2008-06-30

    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{sup -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 < 0.05). In the Cd-added soil, above-ground biomass and root dry weights of tomatoes were increased by 24 and 59%, respectively, in live bacterial inoculation compared to dead bacterial inoculation control. There were no obvious differences in the above-ground tissue and root dry weight of maize and sudangrass between live bacterial inoculation and dead bacterial inoculation. In the soil treated with 50 mg Cd kg{sup -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.

  3. Effect of applying bacterial inoculants containing different types of bacteria to corn silage on the performance of dairy cattle.

    Science.gov (United States)

    Arriola, K G; Kim, S C; Staples, C R; Adesogan, A T

    2011-08-01

    This study examined the effect of applying different bacterial inoculants to corn silage at the time of ensiling on the performance of lactating dairy cows. Corn plants were harvested at 35% dry matter (DM), chopped, and ensiled in 2.4-m-wide bags after application of (1) no inoculant (CON); (2) Biotal Plus II (B2) containing Pediococcus pentosaceus and Propionibacteria freudenreichii; (3) Buchneri 40788 (BUC) containing Lactobacillus buchneri; or (4) Buchneri 500 (B500) containing Pediococcus pentosaceus and L. buchneri. All inoculants were supplied by Lallemand Animal Nutrition (Milwaukee, WI). Each of the 4 silages was included in separate total mixed rations consisting of 44% corn silage, 50% concentrate, and 6% alfalfa hay (DM basis). Fifty-two lactating Holstein cows were stratified according to milk production and parity and randomly assigned at 22 d in milk to the 4 dietary treatments. Cows were fed for ad libitum consumption and milked twice daily for 49 d. Dietary treatment did not affect intakes (kg/d) of DM (20.0), crude protein (CP; 3.7), neutral detergent fiber (NDF; 5.7), or acid detergent fiber (ADF; 3.6), or digestibility (%) of DM (73.9) or CP (72.4). However, NDF digestibility was lower in cows fed B2 compared with those fed other diets (45.3 vs. 53.0%). Consequently, cows fed B2 had lower digestible NDF intake (kg/d) than those fed other diets (2.5 vs. 3.0 kg/d). Dietary treatment did not affect milk yield (32.3 kg/d), efficiency of milk production (1.61), concentrations of milk fat (3.18%) and protein (2.79%), or yields of milk fat (1.03 kg/d) and protein (1.26 kg/d). Inoculant application to corn silage did not affect milk yield or feed intake of cows. PMID:21787933

  4. Physiological, structural and molecular traits activated in strawberry plants after inoculation with the plant growth-promoting bacterium Azospirillum brasilense REC3.

    Science.gov (United States)

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

    2015-05-01

    The plant growth-promoting strain REC3 of Azospirillum brasilense, isolated from strawberry roots, prompts growth promotion and systemic protection against anthracnose disease in this crop. Hence, we hypothesised that A. brasilense REC3 can induce different physiological, structural and molecular responses in strawberry plants. Therefore, the aim of this work was to study these traits activated in Azospirillum-colonised strawberry plants, which have not been assessed until now. Healthy, in vitro micropropagated plants were root-inoculated with REC3 under hydroponic conditions; root and leaf tissues were sampled at different times, and oxidative burst, phenolic compound content, malondialdehyde (MDA) concentration, callose deposition, cell wall fortification and gene expression were evaluated. Azospirillum inoculation enhanced levels of soluble phenolic compounds after 12 h post-inoculation (hpi), while amounts of cell wall bound phenolics were similar in inoculated and control plants. Other early responses activated by REC3 (at 24 hpi) were a decline of lipid peroxidation and up-regulation of strawberry genes involved in defence (FaPR1), bacterial recognition (FaFLS2) and H₂O₂ depuration (FaCAT and FaAPXc). The last may explain the apparent absence of oxidative burst in leaves after bacterial inoculation. Also, REC3 inoculation induced delayed structural responses such as callose deposition and cell wall fortification (at 72 hpi). Results showed that A. brasilense REC3 is capable of exerting beneficial effects on strawberry plants, reinforcing their physiological and cellular characteristics, which in turns contribute to improve plant performance. PMID:25280241

  5. Fermentation parameters, quality and losses in sugarcane silages treated with chemical additives and a bacterial inoculant

    OpenAIRE

    André de Faria Pedroso; Armando de Andrade Rodrigues; Waldomiro Barioni Júnior; Gilberto Batista de Souza

    2011-01-01

    The objective of this trial was to evaluate chemical additives and a bacterial inoculant on the inhibition of alcoholic fermentation and reduction of losses in sugarcane silages. Treatments were (doses on a fresh forage basis): without additive (control); urea (10 g/kg); urea (5 g/kg) + sodium benzoate (0.5 g/kg); sodium benzoate (1 g/kg); urea + ammonium sulfate in a 9:1 relation (10 g/kg); Lactobacillus buchneri (5 × 10(4) cfu/g). Silages were produced in 10.16- × 30-cm PVC tubes, provided ...

  6. 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.

  7. Fermentation parameters, quality and losses in sugarcane silages treated with chemical additives and a bacterial inoculant

    Directory of Open Access Journals (Sweden)

    André de Faria Pedroso

    2011-11-01

    Full Text Available The objective of this trial was to evaluate chemical additives and a bacterial inoculant on the inhibition of alcoholic fermentation and reduction of losses in sugarcane silages. Treatments were (doses on a fresh forage basis: without additive (control; urea (10 g/kg; urea (5 g/kg + sodium benzoate (0.5 g/kg; sodium benzoate (1 g/kg; urea + ammonium sulfate in a 9:1 relation (10 g/kg; Lactobacillus buchneri (5 × 10(4 cfu/g. Silages were produced in 10.16- × 30-cm PVC tubes, provided with tight lids adapted with Bunsen valves for gas losses quantification. Minisilos were opened 139 days after ensiling. Ethanol content (227 g/kg dry matter - DM and total DM loss (30% were high in the control silage. All additives, except benzoate, decreased ethanol concentration in silages. Inoculation with L. buchneri increased acetic acid content in the silage, resulting in a 41% reduction in ethanol content and the lowest gas loss among treatments (15.2%. There was synergistic effect between additives for the combined use of urea and benzoate. Silage treated with urea + ammonium sulfate has higher content of total digestible nutrients than the silage treated with urea exclusively.

  8. Biolistic inoculation of plants with viroid nucleic acids

    Czech Academy of Sciences Publication Activity Database

    Matoušek, Jaroslav; Orctová, Lidmila; Steger, G.; Riesner, D.

    2004-01-01

    Roč. 122, - (2004), s. 153-164. ISSN 0166-0934 R&D Projects: GA MŠk ME 662; GA AV ČR IBS5051014; GA MZe QC1183; GA ČR GA521/03/0072 Keywords : viroids * inoculation Subject RIV: EE - Microbiology, Virology Impact factor: 1.729, year: 2004

  9. Plant Growth-Promoting Rhizobacteria Inoculation to Enhance Vegetative Growth, Nitrogen Fixation and Nitrogen Remobilisation of Maize under Greenhouse Conditions.

    Science.gov (United States)

    Kuan, Khing Boon; Othman, Radziah; Abdul Rahim, Khairuddin; Shamsuddin, Zulkifli H

    2016-01-01

    Plant growth-promoting rhizobacteria (PGPR) may provide a biological alternative to fix atmospheric N2 and delay N remobilisation in maize plant to increase crop yield, based on an understanding that plant-N remobilisation is directly correlated to its plant senescence. Thus, four PGPR strains were selected from a series of bacterial strains isolated from maize roots at two locations in Malaysia. The PGPR strains were screened in vitro for their biochemical plant growth-promoting (PGP) abilities and plant growth promotion assays. These strains were identified as Klebsiella sp. Br1, Klebsiella pneumoniae Fr1, Bacillus pumilus S1r1 and Acinetobacter sp. S3r2 and a reference strain used was Bacillus subtilis UPMB10. All the PGPR strains were tested positive for N2 fixation, phosphate solubilisation and auxin production by in vitro tests. In a greenhouse experiment with reduced fertiliser-N input (a third of recommended fertiliser-N rate), the N2 fixation abilities of PGPR in association with maize were determined by 15N isotope dilution technique at two harvests, namely, prior to anthesis (D50) and ear harvest (D65). The results indicated that dry biomass of top, root and ear, total N content and bacterial colonisations in non-rhizosphere, rhizosphere and endosphere of maize roots were influenced by PGPR inoculation. In particular, the plants inoculated with B. pumilus S1r1 generally outperformed those with the other treatments. They produced the highest N2 fixing capacity of 30.5% (262 mg N2 fixed plant-1) and 25.5% (304 mg N2 fixed plant-1) of the total N requirement of maize top at D50 and D65, respectively. N remobilisation and plant senescence in maize were delayed by PGPR inoculation, which is an indicative of greater grain production. This is indicated by significant interactions between PGPR strains and time of harvests for parameters on N uptake and at. % 15Ne of tassel. The phenomenon is also supported by the lower N content in tassels of maize treated with

  10. Plant Growth-Promoting Rhizobacteria Inoculation to Enhance Vegetative Growth, Nitrogen Fixation and Nitrogen Remobilisation of Maize under Greenhouse Conditions.

    Directory of Open Access Journals (Sweden)

    Khing Boon Kuan

    Full Text Available Plant growth-promoting rhizobacteria (PGPR may provide a biological alternative to fix atmospheric N2 and delay N remobilisation in maize plant to increase crop yield, based on an understanding that plant-N remobilisation is directly correlated to its plant senescence. Thus, four PGPR strains were selected from a series of bacterial strains isolated from maize roots at two locations in Malaysia. The PGPR strains were screened in vitro for their biochemical plant growth-promoting (PGP abilities and plant growth promotion assays. These strains were identified as Klebsiella sp. Br1, Klebsiella pneumoniae Fr1, Bacillus pumilus S1r1 and Acinetobacter sp. S3r2 and a reference strain used was Bacillus subtilis UPMB10. All the PGPR strains were tested positive for N2 fixation, phosphate solubilisation and auxin production by in vitro tests. In a greenhouse experiment with reduced fertiliser-N input (a third of recommended fertiliser-N rate, the N2 fixation abilities of PGPR in association with maize were determined by 15N isotope dilution technique at two harvests, namely, prior to anthesis (D50 and ear harvest (D65. The results indicated that dry biomass of top, root and ear, total N content and bacterial colonisations in non-rhizosphere, rhizosphere and endosphere of maize roots were influenced by PGPR inoculation. In particular, the plants inoculated with B. pumilus S1r1 generally outperformed those with the other treatments. They produced the highest N2 fixing capacity of 30.5% (262 mg N2 fixed plant-1 and 25.5% (304 mg N2 fixed plant-1 of the total N requirement of maize top at D50 and D65, respectively. N remobilisation and plant senescence in maize were delayed by PGPR inoculation, which is an indicative of greater grain production. This is indicated by significant interactions between PGPR strains and time of harvests for parameters on N uptake and at. % 15Ne of tassel. The phenomenon is also supported by the lower N content in tassels of maize

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

    Science.gov (United States)

    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; <3.2% fat 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

  12. Effect of arsenic on tolerance mechanisms of two plant growth-promoting bacteria used as biological inoculants.

    Science.gov (United States)

    Armendariz, Ana L; Talano, Melina A; Wevar Oller, Ana L; Medina, María I; Agostini, Elizabeth

    2015-07-01

    Bacterial ability to colonize the rhizosphere of plants in arsenic (As) contaminated soils is highly important for symbiotic and free-living plant growth-promoting rhizobacteria (PGPR) used as inoculants, since they can contribute to enhance plant As tolerance and limit metalloid uptake by plants. The aim of this work was to study the effect of As on growth, exopolysaccharide (EPS) production, biofilm formation and motility of two strains used as soybean inoculants, Bradyrhizobium japonicum E109 and Azospirillum brasilense Az39. The metabolism of arsenate (As(V)) and arsenite (As(III)) and their removal and/or possible accumulation were also evaluated. The behavior of both bacteria under As treatment was compared and discussed in relation to their potential for colonizing plant rhizosphere with high content of the metalloid. B. japonicum E109 growth was reduced with As(III) concentration from 10 μM while A. brasilense Az39 showed a reduction of growth with As(III) from 500 μM. EPS and biofilm production increased significantly under 25 μM As(III) for both strains. Moreover, this was more notorious for Azospirillum under 500 μM As(III), where motility was seriously affected. Both bacterial strains showed a similar ability to reduce As(V). However, Azospirillum was able to oxidize more As(III) (around 53%) than Bradyrhizobium (17%). In addition, both strains accumulated As in cell biomass. The behavior of Azospirillum under As treatments suggests that this strain would be able to colonize efficiently As contaminated soils. In this way, inoculation with A. brasilense Az39 would positively contribute to promoting growth of different plant species under As treatment. PMID:26141894

  13. Plant Growth-Promoting Rhizobacteria Inoculation to Enhance Vegetative Growth, Nitrogen Fixation and Nitrogen Remobilisation of Maize under Greenhouse Conditions

    Science.gov (United States)

    Kuan, Khing Boon; Othman, Radziah; Abdul Rahim, Khairuddin; Shamsuddin, Zulkifli H.

    2016-01-01

    Plant growth-promoting rhizobacteria (PGPR) may provide a biological alternative to fix atmospheric N2 and delay N remobilisation in maize plant to increase crop yield, based on an understanding that plant-N remobilisation is directly correlated to its plant senescence. Thus, four PGPR strains were selected from a series of bacterial strains isolated from maize roots at two locations in Malaysia. The PGPR strains were screened in vitro for their biochemical plant growth-promoting (PGP) abilities and plant growth promotion assays. These strains were identified as Klebsiella sp. Br1, Klebsiella pneumoniae Fr1, Bacillus pumilus S1r1 and Acinetobacter sp. S3r2 and a reference strain used was Bacillus subtilis UPMB10. All the PGPR strains were tested positive for N2 fixation, phosphate solubilisation and auxin production by in vitro tests. In a greenhouse experiment with reduced fertiliser-N input (a third of recommended fertiliser-N rate), the N2 fixation abilities of PGPR in association with maize were determined by 15N isotope dilution technique at two harvests, namely, prior to anthesis (D50) and ear harvest (D65). The results indicated that dry biomass of top, root and ear, total N content and bacterial colonisations in non-rhizosphere, rhizosphere and endosphere of maize roots were influenced by PGPR inoculation. In particular, the plants inoculated with B. pumilus S1r1 generally outperformed those with the other treatments. They produced the highest N2 fixing capacity of 30.5% (262 mg N2 fixed plant−1) and 25.5% (304 mg N2 fixed plant−1) of the total N requirement of maize top at D50 and D65, respectively. N remobilisation and plant senescence in maize were delayed by PGPR inoculation, which is an indicative of greater grain production. This is indicated by significant interactions between PGPR strains and time of harvests for parameters on N uptake and at. % 15Ne of tassel. The phenomenon is also supported by the lower N content in tassels of maize treated

  14. Responses of Moringa oleifera Lam. plants inoculated with mycorrhizal fungi and submitted to water stress

    Directory of Open Access Journals (Sweden)

    Séfora Gil Gomes Farias

    2008-12-01

    Full Text Available This study was to verify the efficiency of mycorrhizal in Moringa oleifera Lam. plants submitted to water deficit. The experiment was conducted in screenhouse distributted a completely randomized design in a 4x2 factorial with four replications. The first factor was the treatment of inoculation with Glomus etunicatum, Acaulospora scrobiculata, an indigenous community treatment and control (without inoculation. The second factor was the treatment of irrigation and water deficit. Plant height, accumulation of dry weight in the shoots, roots and total and mycorrhizal efficiency were evaluated. The plants inoculated with Glomus etunicatum increases in height, biomass and biomass underground when not subject to water stress. There was no contribution of mycorrhizae to increase the resistance of plants to water deficit, independent of the fungus employee. The efficiency of plants in mycorrhizal, was variable according to the species of fungi used.

  15. Bacterial Gibberellins Induce Systemic Resistance of Plants

    Directory of Open Access Journals (Sweden)

    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

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

    International Nuclear Information System (INIS)

    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)

  17. 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)

    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

  18. Effect of Arbuscular Mycorrhizal Inoculation on Plant Growth and Phthalic Ester Degradation in Two Contaminated Soils

    Institute of Scientific and Technical Information of China (English)

    CHEN Rui-Rui; YIN Rui; LIN Xian-Gui; CAO Zhi-Hong

    2005-01-01

    A 60-day pot experiment was carried out using di-(2-ethylhexyl) phthalate (DEHP) as a typical organic pollutant phthalic ester and cowpea (Vigna sinensis) as the host plant to determine the effect of arbuscular mycorrhizal inoculation on plant growth and degradation of DEHP in two contaminated soils, a yellow-brown soil and a red soil. The air-dried soils were uniformly sprayed with different concentrations of DEHP, inoculated or left uninoculated with an arbuscular mycorrhizal (AM) fungus, and planted with cowpea seeds. After 60 days the positive impact of AM inoculation on the growth of cowpea was more pronounced in the red soil than in the yellow-brown soil, with significantly higher (P < 0.01)mycorrhizal colonization rate, shoot dry weight and total P content in shoot tissues for the red soil. Both in the yellowbrown and red soils, AM inoculation significantly (P < 0.01) reduced shoot DEHP content, implying that AM inoculation could inhibit the uptake and translocation of DEHP from roots to the aboveground parts. However, with AM inoculation no positive contribution to the degradation of DEHP was found.

  19. 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)

    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 (32P 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

  20. 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)

    Highlights: ► Elevated CO2 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 CO2 and microbial inoculation can be explored for CO2- and microbe-assisted phytoextraction technology. - Abstract: Growth and cesium uptake responses of plants to elevated CO2 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 CO2 (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 CO2 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 CO2 than for the control treatment in most cases. Regardless of CO2 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 CO2 and microbial inoculation with regard to plant ability to grow and remove radionuclides from soil can be explored for CO2- and microbe-assisted phytoextraction technology.

  1. Effects of inoculation sources on the enrichment and performance of anode bacterial consortia in sensor typed microbial fuel cells

    Directory of Open Access Journals (Sweden)

    Phuong Tran

    2016-01-01

    Full Text Available Microbial fuel cells are a recently emerging technology that promises a number of applications in energy recovery, environmental treatment and monitoring. In this study, we investigated the effect of inoculating sources on the enrichment of electrochemically active bacterial consortia in sensor-typed microbial fuel cells (MFCs. Several MFCs were constructed, operated with modified artificial wastewater and inoculated with different microbial sources from natural soil, natural mud, activated sludge, wastewater and a mixture of those sources. After enrichment, the MFCs inoculated with the natural soil source generated higher and more stable currents (0.53±0.03 mA, in comparisons with the MFCs inoculated with the other sources. The results from denaturing gradient gel electrophoresis (DGGE showed that there were significant changes in bacterial composition from the original inocula to the enriched consortia. Even more interestingly, Pseudomonas sp. was found dominant in the natural soil source and also in the corresponding enriched consortium. The interactions between Pseudomonas sp. and other species in such a community are probably the key for the effective and stable performance of the MFCs.

  2. Impact of rhizobial inoculation and nitrogen utilization in plant growth promotion of maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    RAMESH K. SINGH

    2013-05-01

    Full Text Available Singh RK, Malik N, Singh S. 2013. Impact of rhizobial inoculation and nitrogen utilization in plant growth promotion of maize (Zea mays L.. Nusantara Bioscience 5: 8-14. During the course of growing population demands there has been an increasing interest in exploring the possibility of extending the beneficial interaction between cereals and plant growth promoting rhizobacteria (PGPR. Endophytes are a group of microorganism that resides mostly in the intercellular space of various parts of plants including cereals. Assessment of plant growth promoting properties of the five-rhizobial strains belonging to α subclass i.e. Rhizobium leguminosarum bv. phaseoli RRE6 and R. undicola RRE36 and those belonging to β subclass i.e. Burkholderia cepacia (RRE3, RRE5, RRE25 was done by growing maize plants inoculated with these strains. Inoculated maize plants showed a significant increase in plant height, root length, shoot and root dry weight over uninoculated control. R. leguminosarum bv. phaseoli RRE6 and B. cepacia RRE5 among the α and β-subclass representatives respectively, gave the best inoculation response. Effect of nitrate supplementation upon maize-RRE6 and RRE5 association was also studied and a significant increase in all the growth parameters and colonization ability was recorded when nitrate was present as a supplement over uninoculated control and maize-RRE6 and RRE5 in absence of external nitrate.

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

    Science.gov (United States)

    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. PMID:27155239

  4. Biolistic inoculation of plants with pospiviroid nucleic acids

    Czech Academy of Sciences Publication Activity Database

    Matoušek, Jaroslav; Orctová, Lidmila; Steger, G.; Riesner, D.

    Rennes : INRARennesService communication, 2004. s. 68. [EAPR Virology Section Meeting /12./. 13.06.2004-19.06.2004, Rennes] R&D Projects: GA AV ČR IBS5051014; GA MZe QC1183; GA ČR GA521/03/0072; GA MŠk ME 662 Keywords : plant pathology * viroids Subject RIV: EE - Microbiology, Virology

  5. Enhancement of Chilling Resistance of Inoculated Grapevine Plantlets with a Plant Growth-Promoting Rhizobacterium, Burkholderia phytofirmans Strain PsJN▿

    OpenAIRE

    Ait Barka, Essaid; Nowak, Jerzy; Clément, Christophe

    2006-01-01

    In vitro inoculation of Vitis vinifera L. cv. Chardonnay explants with a plant growth-promoting rhizobacterium, Burkholderia phytofirmans strain PsJN, increased grapevine growth and physiological activity at a low temperature. There was a relationship between endophytic bacterial colonization of the grapevine plantlets and their growth at both ambient (26°C) and low (4°C) temperatures and their sensitivities to chilling. The major benefits of bacterization were observed on root growth (11.8- ...

  6. Inoculating plants with the endophytic bacterium Pseudomonas sp. Ph6-gfp to reduce phenanthrene contamination.

    Science.gov (United States)

    Sun, Kai; Liu, Juan; Gao, Yanzheng; Sheng, Yuehui; Kang, Fuxing; Waigi, Michael Gatheru

    2015-12-01

    Plant organic contamination poses a serious threat to the safety of agricultural products and human health worldwide, and the association of endophytic bacteria with host plants may decrease organic pollutants in planta. In this study, we firstly determined the growth response and biofilm formation of endophytic Pseudomonas sp. Ph6-gfp, and then systematically evaluated the performance of different plant colonization methods (seed soaking (SS), root soaking (RS), leaf painting (LP)) for circumventing the risk of plant phenanthrene (PHE) contamination. After inoculation for 48 h, strain Ph6-gfp grew efficiently with PHE, oxalic acid, or malic acid as the sole sources of carbon and energy. Moreover, strain Ph6-gfp could form robust biofilms in LB medium. In greenhouse hydroponic experiments, strain Ph6-gfp could actively colonize inoculated plants internally, and plants colonized with Ph6-gfp showed a higher capacity for PHE removal. Compared with the Ph6-gfp-free treatment, the accumulations of PHE in Ph6-gfp-colonized plants via SS, RS, and LP were 20.1, 33.1, and 7.1 %, respectively, lower. Our results indicate that inoculating plants with Ph6-gfp could lower the risk of plant PHE contamination. RS was most efficient for improving PHE removal in whole plant bodies by increasing the cell numbers of Ph6-gfp in plant roots. The findings in this study provide an optimized method to strain Ph6-gfp reduce plant PAH residues, which may be applied to agricultural production in PAH-contaminated soil. PMID:26263885

  7. Plant Natural Products Targeting Bacterial Virulence Factors.

    Science.gov (United States)

    Silva, Laura Nunes; Zimmer, Karine Rigon; Macedo, Alexandre José; Trentin, Danielle Silva

    2016-08-24

    Decreased antimicrobial efficiency has become a global public health issue. The paucity of new antibacterial drugs is evident, and the arsenal against infectious diseases needs to be improved urgently. The selection of plants as a source of prototype compounds is appropriate, since plant species naturally produce a wide range of secondary metabolites that act as a chemical line of defense against microorganisms in the environment. Although traditional approaches to combat microbial infections remain effective, targeting microbial virulence rather than survival seems to be an exciting strategy, since the modulation of virulence factors might lead to a milder evolutionary pressure for the development of resistance. Additionally, anti-infective chemotherapies may be successfully achieved by combining antivirulence and conventional antimicrobials, extending the lifespan of these drugs. This review presents an updated discussion of natural compounds isolated from plants with chemically characterized structures and activity against the major bacterial virulence factors: quorum sensing, bacterial biofilms, bacterial motility, bacterial toxins, bacterial pigments, bacterial enzymes, and bacterial surfactants. Moreover, a critical analysis of the most promising virulence factors is presented, highlighting their potential as targets to attenuate bacterial virulence. The ongoing progress in the field of antivirulence therapy may therefore help to translate this promising concept into real intervention strategies in clinical areas. PMID:27437994

  8. Bacterial Modulation of Plant Ethylene Levels.

    Science.gov (United States)

    Gamalero, Elisa; Glick, Bernard R

    2015-09-01

    A focus on the mechanisms by which ACC deaminase-containing bacteria facilitate plant growth.Bacteria that produce the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, when present either on the surface of plant roots (rhizospheric) or within plant tissues (endophytic), play an active role in modulating ethylene levels in plants. This enzyme activity facilitates plant growth especially in the presence of various environmental stresses. Thus, plant growth-promoting bacteria that express ACC deaminase activity protect plants from growth inhibition by flooding and anoxia, drought, high salt, the presence of fungal and bacterial pathogens, nematodes, and the presence of metals and organic contaminants. Bacteria that express ACC deaminase activity also decrease the rate of flower wilting, promote the rooting of cuttings, and facilitate the nodulation of legumes. Here, the mechanisms behind bacterial ACC deaminase facilitation of plant growth and development are discussed, and numerous examples of the use of bacteria with this activity are summarized. PMID:25897004

  9. Cyanobacterial inoculation elicits plant defense response and enhanced Zn mobilization in maize hybrids

    Directory of Open Access Journals (Sweden)

    Radha Prasanna

    2015-12-01

    Full Text Available The present investigation evaluated the effect of inoculating different cyanobacterial formulations on a set of hybrids of maize, in terms of plant defense enzyme activity, soil health parameters, Zn concentration, and yields. Microbial inoculation showed significant effects on accumulation of Zn in flag leaf, with A4 (Anabaena–Azotobacter biofilm recording the highest values. Analysis of variance (ANOVA indicated that both the hybrids and cyanobacterial treatments brought about significant variation in terms of glomalin-related soil proteins and polysaccharides in soil and the activity of defense enzymes in roots and shoots of the plants. Cyanobacterial inoculants—A4 (Anabaena–Azotobacter biofilm and A1 (Anabaena sp.–Providencia sp., CW1 + PW5 enhanced the activity of peroxidase, PAL and PPO in roots, which also showed a positive correlation with Zn concentration in the flag leaf. Grain yield ranged from 7.0 to 7.29 t/ha among the different inoculants. Comparative analyses of treatments showed that A3 (Anabaena–Trichoderma-biofilmed formulation and hybrid B8 (Bio-9681 were superior in terms of parameters investigated. This represents the first report on the genotypic responses of maize hybrids to cyanobacteria-based inoculants. Future research should focus on dissecting the role of root exudates and cyanobacteria-mediated Zn mobilization pathway in maize.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. 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

    OpenAIRE

    Erineudo de Lima Canuto; André Luis Martinez de Oliveira; Verônica Massena Reis; José Ivo Baldani

    2003-01-01

    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 th...

  12. Microbial Inoculation Improves Growth of Oil Palm Plants (Elaeis guineensis Jacq.)

    OpenAIRE

    Om, Azlin Che; Ghazali, Amir Hamzah Ahmad; Keng, Chan Lai; Ishak, Zamzuri

    2009-01-01

    Introduction of diazotrophic rhizobacteria to oil palm tissues during the in vitro micropropagation process establishes an early associative interaction between the plant cells and bacteria. In the association, the diazotrophs provide the host plants with phytohormones and fixed nitrogen. This study was conducted to observe growth of bacterised tissue cultured oil palm plants under ex vitro conditions after 280 days of growth. Root dry weight, shoot dry weight, root volume, bacterial colonisa...

  13. Effect of planting methods and cyanobacterial inoculants on yield, water productivity and economics of rice cultivation

    Directory of Open Access Journals (Sweden)

    Amit A. Shahane

    2015-09-01

    Full Text Available The impact of two crop planting methods and of the application of cyanobacterial inoculants on plant growth, yield, water productivity and economics of rice cultivation was evaluated with the help of a split plot designed experiment during the rainy season of 2011 in New Delhi, India. Conventional transplanting and system of rice intensification (SRI were tested as two different planting methods and seven treatments that considered cyanobacterial inoculants and compost were applied with three repetitions each. Results revealed no significant differences in plant performance and crop yield between both planting methods. However, the application of biofilm based BGA bio-fertiliser + 2/3 N had an overall positive impact on both, plant performance (plant height, number of tillers and crop yield (number and weight of panicles as well as on grain and straw yield. Higher net return and a higher benefit-cost ratio were observed in rice fields under SRI planting method, whereas the application of BGA + PGPR + 2/3 N resulted in highest values. Total water productivity and irrigation water productivity was significantly higher under SRI practices (5.95 and 3.67 kg ha^(-1 mm^(-1 compared to practices of conventional transplanting (3.36 and 2.44, meaning that using SRI method, water saving of about 34 % could be achieved and significantly less water was required to produce one kg of rice. This study could show that a combination of plant growth promoting rhizobacteria (PGPR in conjunction with BGA and 2/3 dose of mineral N fertiliser can support crop growth performance, crop yields and reduces overall production cost, wherefore this practices should be used in the integrated nutrient management of rice fields in India.

  14. A LIQUID CHROMATOGRAPHY METHOD FOR THE DETERMINATION OF CURCUMIN IN PGPR INOCULATED CURCUMA LONGA . L PLANT

    Directory of Open Access Journals (Sweden)

    U. Boominathan* and P.K. Sivakumaar

    2012-11-01

    Full Text Available A rapid and simple HPLC method has been developed for the quantification of curcumin in PGPR inoculated curcuma longa plant. Treatment of PGPR such as Pseudomonas fluorescens and Bacillus megaterium improved the content of curcumin in rhizomes sample. The PGPR treated rhizomes were higher in curcumin content than the PGPR untreated plant rhizomes sample. Analysis was performed using a C18 column (250 X 4.6 mm by isocratic elution with 50mM potassium dihydrogen orthophosphate (pH 3.5: Acetonitrile (40:60 and detection at 420 nm and 340 nm using a photodiode array detector for curcumin respectively. The calibration plot was linear over the range studied (Curcumin: 100 – 3200ng/mL with a correlation of 0.999. The method was also validated for the precision and recovery. Thus, the method is suitable for routine analysis of curcumin in PGPR inoculated curcuma longa plant sample 1, compared with PGPR uninoculated plant sample 2.

  15. 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

  16. Inoculation of sugarcane with diazotrophic bacteria

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Xylella Genomics and Bacterial Pathogenicity to Plants

    OpenAIRE

    Dow, J. M.; Daniels, M. J.

    2000-01-01

    Xylella fastidiosa, a pathogen of citrus, is the first plant pathogenic bacterium for which the complete genome sequence has been published. Inspection of the sequence reveals high relatedness to many genes of other pathogens, notably Xanthomonas campestris. Based on this, we suggest that Xylella possesses certain easily testable properties that contribute to pathogenicity. We also present some general considerations for deriving information on pathogenicity from bacterial genomics.

  19. Migration of Fusarium verticillioides between inoculated and non-inoculated ears of field-grown corn plants

    Science.gov (United States)

    Consequences of Fusarium verticillioides colonization of corn kernels may be plant disease and/or mycotoxin production. Plant disease may reduce crop production and mycotoxins may cause harmful, and often fatal, effects on humans and animals. Understanding migration patterns of F. verticillioides ...

  20. The olive knot disease as a model to study the role of interspecies bacterial communities in plant disease.

    Science.gov (United States)

    Buonaurio, Roberto; Moretti, Chiaraluce; da Silva, Daniel Passos; Cortese, Chiara; Ramos, Cayo; Venturi, Vittorio

    2015-01-01

    There is an increasing interest in studying interspecies bacterial interactions in diseases of animals and plants as it is believed that the great majority of bacteria found in nature live in complex communities. Plant pathologists have thus far mainly focused on studies involving single species or on their interactions with antagonistic competitors. A bacterial disease used as model to study multispecies interactions is the olive knot disease, caused by Pseudomonas savastanoi pv. savastanoi (Psv). Knots caused by Psv in branches and other aerial parts of the olive trees are an ideal niche not only for the pathogen but also for many other plant-associated bacterial species, mainly belonging to the genera Pantoea, Pectobacterium, Erwinia, and Curtobacterium. The non-pathogenic bacterial species Erwinia toletana, Pantoea agglomerans, and Erwinia oleae, which are frequently isolated inside the olive knots, cooperate with Psv in modulating the disease severity. Co-inoculations of these species with Psv result in bigger knots and better bacterial colonization when compared to single inoculations. Moreover, harmless bacteria co-localize with the pathogen inside the knots, indicating the formation of stable bacterial consortia that may facilitate the exchange of quorum sensing signals and metabolites. Here we discuss the possible role of bacterial communities in the establishment and development of olive knot disease, which we believe could be taking place in many other bacterial plant diseases. PMID:26113855

  1. A study on the effect of the bacterial inoculant on corn silage quality,digestibility and performance in dairy cattle

    Institute of Scientific and Technical Information of China (English)

    Wang Jianhua; Wu Zilin; Michael K Woolford; Diao Qiyu; Cai Huiyi

    2005-01-01

    Effect of the bacterial inoculant Sil-All (short for ‘SA') on corn silage quality, digestibility and performance in dairy cattle was studied. SA treated silage resulted in the higher level of retained protein and slightly higher level of residual sugars in that treatment, the better digestibility of the neutral detergent fibre (NDF) and the acid detergent fibre (ADF), the lower pH and evolution of ammonia compared to the control; The fall in pH was most rapid in the SA treated silage in the first 4 days of ensilage, when it matters most for the conservation of protein, compared with the control silage and this was linked more to both lactic and total acids. Both volatile fatty acid (VFA) and lactate content increased with ensiling time, increase degree reached up near 100%; Lactate content in treatment silage was higher than that in the control, and this difference was all maintained at the level of approximately 7%~13% almost in all cases, at length, up 16% in the case of day 15; pH value decreased with ensiling time. Moreover, pH value in most of treatment were lower than that in thecontrol; The digestibility of both dry matter (DM) and crude protein (CP) was appreciably improved by the use of inoculant SA. Also, in relation to reductions, of NDF and ADF were noted. An increase in milk yield of the order of 0.9kg per head per day in favour of SA was observed. Alternatively, with an average daily feed intake of 20kg, this indicates with 1ton of corn silage milk yield could be increased by 46.5kg.

  2. Feasibility of EPS-producing bacterial inoculation to speed up the sand aggregation in the Gurbantunggut Desert, Northwestern China.

    Science.gov (United States)

    Wu, Nan; Pan, Hui-Xia; Qiu, Dong; Zhang, Yuan-Ming

    2014-12-01

    Exopolymers are known to be useful in improving sand aggregation and the development of biological soil crusts (BSCs). A facultative bacterium KLBB0001 was isolated from BSCs in the Gurbantunggut Desert in northwestern China. With the strong effective production of extracellular polymeric substances (EPS), this strain exhibits a multifunctional role for sand stabilization and maintenance of water under laboratory conditions. Practical testing of the feasibility of its inoculation to speed up BSC recovery in the field was also conducted in this experiment. This strain stimulated the heterotrophic community assembly in the topsoil layer (0-2 cm) before the commencement of autotrophic cyanobacteria, while also significantly increasing the number of bacteria, actinomycetes, and content of total phosphorus, available nitrogen, and available phosphorus. However, the low nitrogenase activity (NA) (0.57 µmol/h) that was observed caused us to doubt the previous identification as Azotobacter Beijerinck that was based on physiological and biochemical properties. A phylogenetic analysis based on 16S rRNA gene sequences revealed that this strain was a member of the genus Paenibacillus. It exhibited the closest phylogenetic affinity and highest sequence similarity to the strain Paenibacillus mucilaginosus VKPM B-7519 (sequence similarity 99.698%), which is well known as a typical silicate-weathering bacteria that releases lots of nutritional ions from minerals and the soil. Because P. mucilaginosus can excrete carbonic anhydrase (CA) to capture atmospheric CO2 through hydration of CO2 , it is possible that KLBB0001 might use a similar strategy for heterotrophs in the BSCs to sequester CO2 from the air. Because of its potential role in the reestablishment of the BSC ecosystem due to its ability to improve water relations, sand stabilization, and chemical erosion, EPS-producing bacterial inoculation was concluded to be a suitable and effective treatment for BSC recovery

  3. Lotus japonicus plants of the Gifu B-129 ecotype subjected to alkaline stress improve their Fe(2+) bio-availability through inoculation with Pantoea eucalypti M91.

    Science.gov (United States)

    Campestre, María Paula; Castagno, Luis Nazareno; Estrella, María Julia; Ruiz, Oscar Adolfo

    2016-03-15

    Inoculation assays with Pantoea eucalypti M91 were performed on Lotus japonicus ecotype Gifu. Under alkaline conditions, this ecotype is characterized by the development of interveinal chlorosis of the apical leaves due to low mobilization of Fe(2+). Inoculation with P. eucalypti M91, a plant growth-promoting bacterial strain capable of producing pyoverdine-like and pyochelin-like siderophores under alkaline growth conditions, alters the root, resulting in a herringbone pattern of root branching. Additional features include improvement in Fe(2+) transport to the shoots, acidification of the hydroponic solution of the plant cultures, and an accompanying increase in the efficiency of the PSII parameters. In addition, there was an increase in the expression of the FRO1 and IRT1 genes, accompanied by a significant increase in FRO activity. Results showed that P. eucalypti M91 has a beneficial effect on the Fe acquisition machinery of Strategy I, as described for non-graminaceous monocots and dicots, suggesting its potential as an inoculant for legume crops cultivated in alkaline soils. PMID:26815729

  4. Differential Response of Potato Toward Inoculation with Taxonomically Diverse Plant Growth Promoting Rhizobacteria

    Science.gov (United States)

    Naqqash, Tahir; Hameed, Sohail; Imran, Asma; Hanif, Muhammad Kashif; Majeed, Afshan; van Elsas, Jan Dirk

    2016-01-01

    Rhizosphere engineering with beneficial plant growth promoting bacteria offers great promise for sustainable crop yield. Potato is an important food commodity that needs large inputs of nitrogen and phosphorus fertilizers. To overcome high fertilizer demand (especially nitrogen), five bacteria, i.e., Azospirillum sp. TN10, Agrobacterium sp. TN14, Pseudomonas sp. TN36, Enterobacter sp. TN38 and Rhizobium sp. TN42 were isolated from the potato rhizosphere on nitrogen-free malate medium and identified based on their 16S rRNA gene sequences. Three strains, i.e., TN10, TN38, and TN42 showed nitrogen fixation (92.67–134.54 nmol h-1mg-1 protein), while all showed the production of indole-3-acetic acid (IAA), which was significantly increased by the addition of L-tryptophan. Azospirillum sp. TN10 produced the highest amount of IAA, as measured by spectrophotometry (312.14 μg mL-1) and HPLC (18.3 μg mL-1). Inoculation with these bacteria under axenic conditions resulted in differential growth responses of potato. Azospirillum sp. TN10 incited the highest increase in potato fresh and dry weight over control plants, along with increased N contents of shoot and roots. All strains were able to colonize and maintain their population densities in the potato rhizosphere for up to 60 days, with Azospirillum sp. and Rhizobium sp. showing the highest survival. Plant root colonization potential was analyzed by transmission electron microscopy of root sections inoculated with Azospirillum sp. TN10. Of the five test strains, Azospirillum sp. TN10 has the greatest potential to increase the growth and nitrogen uptake of potato. Hence, it is suggested as a good candidate for the production of potato biofertilizer for integrated nutrient management. PMID:26925072

  5. Differential Response of Potato Toward Inoculation with Taxonomically Diverse Plant Growth Promoting Rhizobacteria.

    Science.gov (United States)

    Naqqash, Tahir; Hameed, Sohail; Imran, Asma; Hanif, Muhammad Kashif; Majeed, Afshan; van Elsas, Jan Dirk

    2016-01-01

    Rhizosphere engineering with beneficial plant growth promoting bacteria offers great promise for sustainable crop yield. Potato is an important food commodity that needs large inputs of nitrogen and phosphorus fertilizers. To overcome high fertilizer demand (especially nitrogen), five bacteria, i.e., Azospirillum sp. TN10, Agrobacterium sp. TN14, Pseudomonas sp. TN36, Enterobacter sp. TN38 and Rhizobium sp. TN42 were isolated from the potato rhizosphere on nitrogen-free malate medium and identified based on their 16S rRNA gene sequences. Three strains, i.e., TN10, TN38, and TN42 showed nitrogen fixation (92.67-134.54 nmol h(-1)mg(-1) protein), while all showed the production of indole-3-acetic acid (IAA), which was significantly increased by the addition of L-tryptophan. Azospirillum sp. TN10 produced the highest amount of IAA, as measured by spectrophotometry (312.14 μg mL(-1)) and HPLC (18.3 μg mL(-1)). Inoculation with these bacteria under axenic conditions resulted in differential growth responses of potato. Azospirillum sp. TN10 incited the highest increase in potato fresh and dry weight over control plants, along with increased N contents of shoot and roots. All strains were able to colonize and maintain their population densities in the potato rhizosphere for up to 60 days, with Azospirillum sp. and Rhizobium sp. showing the highest survival. Plant root colonization potential was analyzed by transmission electron microscopy of root sections inoculated with Azospirillum sp. TN10. Of the five test strains, Azospirillum sp. TN10 has the greatest potential to increase the growth and nitrogen uptake of potato. Hence, it is suggested as a good candidate for the production of potato biofertilizer for integrated nutrient management. PMID:26925072

  6. Differential growth stimulation response of potato towards inoculation with taxonomically diverse plant growth promoting rhizobacteria

    Directory of Open Access Journals (Sweden)

    Tahir eNaqqash

    2016-02-01

    Full Text Available Rhizosphere engineering with beneficial plant growth promoting bacteria offers great promise for sustainable crop yield. Potato is an important food commodity that needs large inputs of nitrogen and phosphorus fertilizers. To overcome high fertilizer demand (especially nitrogen, five bacteria, i.e. Azospirillum sp.TN10, Agrobacterium sp.TN14, Pseudomonas sp.TN36, Enterobactersp. TN38 and Rhizobium sp. TN42 were isolated from the potato rhizosphere on nitrogen-free malate medium and identified based on their 16S rRNA gene sequences. Three strains, i.e. TN10, TN38 and TN42, showed nitrogen fixation (92.67-134.54 nmol h-1mg-1protein, while all showed the production of indole acetic acid in the presence and/or absence of L-tryptophan. Azospirillum sp. TN10 produced the highest amount of IAA, as measured by spectrophotometry (312.14 µg mL-1 and HPLC (18.3 µg mL-1. Inoculation with these bacteria under axenic conditions resulted in differential growth responses of potato. Azospirillum sp. TN10 incited the highest increase in potato fresh and dry weight over control plants, along with increased N contents of shoot and roots. All strains were able to colonize and maintain their population densities in the potato rhizosphere for upto 60 days, with Azospirillum sp. and Rhizobium sp. showing the highest survival. Plant root colonization potential was analyzed by transmission electron microscopy of root sections inoculated with Azospirillum sp. TN10. Of the five test strains, Azospirillum sp. TN10 has the greatest potential to increase the growth and nitrogen uptake of potato. Hence, it is suggested as a good candidate for the production of potato biofertilizer for integrated nutrient management with potato.

  7. 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)

    Alfalfa (Medicago sativa L.) plants susceptible (S) and resistant (R) to bacterial wilt were fed via roots with a nutrient solution labelled with 86Rb+, at different times after inoculation with Corynebacterium insidiosum (McCull.) H.L. Jens. The infection did not affect 86Rb+ 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. 86Rb+ uptake significantly decreased due to the infection in the S-plants on the day 49 after inoculation (a 4-h-exposure to 86Rb+), 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)

  8. Effects of inoculation of plant-growth promoting bacteria on Ni uptake by Indian mustard

    OpenAIRE

    Rajkumar, Mani; Freitas, Helena

    2008-01-01

    In this study, among a collection of Ni resistant bacterial strains isolated from serpentine soil, two plant growth promoting bacteria (PGPB), Ps29C and Bm4C were selected based on their ability to utilize ACC as the sole N source and promote seedling growth in roll towel assay. The Ni resistant PGPB, Ps29C and Bm4C were characterized as Pseudomonas sp. and Bacillus megaterium, respectively, on the basis of their 16s rDNA sequences. Assessment of the parameters of plant growth promotion revea...

  9. Proline and Abscisic Acid Content in Droughted Corn Plant Inoculated with Azospirillum sp. and Arbuscular Mycorrhizae Fungi

    Directory of Open Access Journals (Sweden)

    NOVRI YOULA KANDOWANGKO

    2009-03-01

    Full Text Available Plants that undergo drought stress perform a physiological response such as accumulation of proline in the leaves and increased content abscisic acid. A research was conducted to study proline and abscisic acid (ABA content on drought-stressed corn plant with Azospirillum sp. and arbuscular mycorrhizae fungi (AMF inoculated at inceptisol soil from Bogor, West Java. The experiments were carried out in a green house from June up to September 2003, using a factorial randomized block design. In pot experiments, two factors were assigned, i.e. inoculation with Azospirillum (0, 0.50, 1.00, 1.50 ml/pot and inoculation with AMF Glomus manihotis (0, 12.50, 25.00, 37.50 g/pot. The plants were observed during tasseling up to seed filling periods. Results of experiments showed that the interaction between Azospirillum sp. and AMF was synergistically increased proline, however it decreased ABA.

  10. Susceptibility of pea, horse bean and bean to viruses in dependence on the age of the inoculated plants

    OpenAIRE

    Władysław Błaszczak; Grażyna Ellmann-Wąsik; Renata Lesiak-Jerzyk

    2013-01-01

    Three cultivars of pea did not differ in their susceptibility to Cucumber Mosaic Virus (CMV) notwithstanding the age of the inoculated plants. But their susceptibility to infection with Bean Yellow Mosaic Virus (BYMV) differed. Horse bean cultivars 'Nadwiślański' and 'Major' proved to be less susceptible to Broad Bean True Mosaic Virus (BBTMV) when older plants were-inoculated. Two bean cultivars 'Złota Saxa' and 'Earle' appeared to be susceptible to BBTMV only in the phase of developing prim...

  11. In situ stimulation vs. bioaugmentation: Can microbial inoculation of plant roots enhance biodegradation of organic compounds?

    Energy Technology Data Exchange (ETDEWEB)

    Kingsley, M.T.; Metting, F.B. Jr.; Fredrickson, J.K. [Pacific Northwest Lab., Richland, WA (United States); Seidler, R.J. [Environmental Protection Agency, Corvallis, OR (United States). Environmental Research Lab.

    1993-06-01

    The use of plant roots and their associated rhizosphere bacteria for biocontainment and biorestoration offers several advantages for treating soil-dispersed contaminants and for application to large land areas. Plant roots function as effective delivery systems, since root growth transports bacteria vertically and laterally along the root in the soil column (see [ 1,2]). Movement of microbes along roots and downward in the soil column can be enhanced via irrigation [1-4]. For example, Ciafardini et al. [3] increased the nodulation and the final yield of soybeans during pod filling by including Bradyrhizobium japonicum in the irrigation water. Using rhizosphere microorganisms is advantageous for biodegradation of compounds that are degraded mainly by cometabolic processes, e.g., trichloroethylene (TCE). The energy source for bacterial growth and metabolism is supplied by the plant in the form of root exudates and other sloughed organic material. Plants are inexpensive, and by careful choice of species that possess either tap or fibrous root growth patterns, they can be used to influence mass transport of soil contaminants to the root surface via the transpiration stream [5]. Cropping of plants to remove heavy metals from contaminated soils has been proposed as a viable, low-cost, low-input treatment option [6]. The interest in use of plants as a remediation strategy has even reached the popular press [7], where the use of ragweed for the reclamation of sites contaminated with tetraethyl lead and other heavy metals was discussed.

  12. Comparison and evaluation of experimental mediastinitis models: precolonized foreign body implants and bacterial suspension inoculation seems promising

    Directory of Open Access Journals (Sweden)

    Kose Necmi

    2006-04-01

    Full Text Available Abstract Background Post-sternotomy mediastinitis (PSM is a devastating surgical complication affecting 1–3% of patients that undergo cardiac surgery. Staphylococcus aureus is one of the most commonly encountered bacterial pathogen cultured from mediastinal samples obtained from patients with PSM. A component of the membrane of the gram positive bacteria, lipoteichoic acid, stimulates the blood monocytes and macrophages to secrete cytokines, radicals and nitrogen species leading to oxido-inflammatory damage. This seems to be responsible for the high mortality rate in PSM. For the evaluation of the pathogenesis of infection or for the investigation of alternative treatment models in infection, no standard model of mediastinitis seems to be available. In this study, we evaluated four mediastinitis models in rats. Methods The rats were divided into four groups to form different infection models. Group A: A suspension of 1 × 107 colony-forming units Staphylococcus aureus in 0,5 mL was inoculated from the right second intercostal space into the mediastinum. Group B: A hole was created in the right second intercostal space and a piece of stainless-steel implant with a length of 0.5 cm was inserted into the mediastinum and a suspension of 1 × 107 cfu bacteria in 0,5 mL was administered via the tail vein. Group C: Precolonized stainless-steel implant was inserted into the mediastinum. Group D: Precolonized stainless-steel implant was inserted into the mediastinum and the bacteria suspension was also injected into the mediastinum. On the 10th day, rats were sacrificed and the extension of infection in the mediastenae was evaluated by quantitative cultures. Myeloperoxidase activity (MPO and malondialdehyde (MDA levels were determined in the sera to evaluate the neutrophil activation and assess the inflammatory oxidation. Results The degree of infection in group C and D were 83.3% and 100% respectively (P P Conclusion Infected implants and high

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

    OpenAIRE

    Joelma da Silva Santos; Tarciana de Oliveira Viana; Cristina Meira de Jesus; Vera Lúcia Divan Baldani; Joilson Silva Ferreira

    2015-01-01

    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 Uni...

  14. COMPARING INOCULATION METHODS TO EVALUATE THE GROWTH OF Xanthomonas axonopodis pv. manihotis ON CASSAVA PLANTS

    Directory of Open Access Journals (Sweden)

    Alejandra Muñoz Bodnar

    2014-11-01

    Full Text Available Xanthomonas axonopodis pv. manihotis (Xam is the causal agent of cassava bacterial blight (CBB, a major disease for cassava crops in South America and Africa. Until now the development of the disease is measured via AUDPC (Area Under Disease Progress Curve but no reliable quantitative methods are available probably due to high variability of bacterial growth in planta. To establish an accurate method for bacterial quantification during the course of Xam infection within the host tissues, we analyzed bacterial populations upon stem and leaf-puncturing as well as leaf-clipping of cassava varieties MCOL1522 and SG107-35 challenged with the virulent Xam strain CIO151. Here, we show that the movement of bacteria along the tissues and especially in leaves is stochastic. Moreover, we were able to demonstrate differential growth of virulent Xam strain CIO151 upon stem-puncturing and quantification of bacteria 6 cm. away from the inoculation point of two varieties displaying contrasting levels of susceptibility.RESUMEN Normal 0 21 false false false ES-CO X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Xanthomonas axonopodis pv. manihotis (Xam es el agente causal del tizón bacteriano de la yuca, una de las principales enfermedades de los cultivos de yuca en América del Sur y África. Hasta ahora, el desarrollo de la

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

    Directory of Open Access Journals (Sweden)

    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.

  16. Susceptibility of pea, horse bean and bean to viruses in dependence on the age of the inoculated plants

    Directory of Open Access Journals (Sweden)

    Władysław Błaszczak

    2013-12-01

    Full Text Available Three cultivars of pea did not differ in their susceptibility to Cucumber Mosaic Virus (CMV notwithstanding the age of the inoculated plants. But their susceptibility to infection with Bean Yellow Mosaic Virus (BYMV differed. Horse bean cultivars 'Nadwiślański' and 'Major' proved to be less susceptible to Broad Bean True Mosaic Virus (BBTMV when older plants were-inoculated. Two bean cultivars 'Złota Saxa' and 'Earle' appeared to be susceptible to BBTMV only in the phase of developing primary leaves and the age-dependent resistance to infection increased faster in plants of the cv. 'Złota Saxa'. Both cultivars of bean showed also age-dependent resistance to infection by BYMV. All these viruses restricted growth and yield of plants. The decreases were greater when younger plants were inoculated. These dependences appeared most distinctly in pea cv. 'Sześciotygodniowy' infected with CMV and in two cultivars of bean infected with BYMV.

  17. Effects of Organic and Chemical Fertilizations and Microbe Inoculation on Physiology and Growth ofSweet Corn Plants

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A pot culture experiment was carried out in a glasshouse to compare the physiology and growth of sweet corn plants (Zea mays L. cv. Honey Bantam) grown under organic and chemical fertilizations with or without microbial inoculation (MI). The organic fertilizer used was fermented mainly using rice bran and oil mill sludge, and the MI was a liquid product containing many beneficial microbes such as lactic acid bacteria, yeast, photosynthetic bacteria and actinomycetes. The application amounts of the organic fertilizer and chemical fertilizers were based on the same rate of nitrogen, phosphorus and potassium. Sweet corn plants fertilized with organic materials inoculated with beneficial microbes grew better than those without inoculation. There were no significant differences in physiology and growth of the sweet corn plants between treatments of chemical fertilizers with and without MI. Among the organic fertilization treatments, only the sweet corn plants with organic fertilizer and MI applied 4 weeks before sowing had similar photosynthetic capacity, total dry matter yield and ear yield to those with chemical fertilizers. Sweet corn plants in other organic fertilization treatments were weaker in physiology and growth than those in chemical fertilization treatments. There was no significant variance among chemical fertilization treatments at different time. It is concluded from this research that this organic fertilizer would be more effective if it was inoculated with the beneficial microbes. Early application of the organic fertilizer with beneficial microbes before sowing was recommended to make the nutrients available before the rapid growth at the early stage and obtain a yield similar to or higher than that with chemical fertilizations.

  18. Using bacterial inoculants to control the growth of E. coli O157:H7 in maize silages under anaerobic and aerobic conditions

    International Nuclear Information System (INIS)

    Full text: The aim was to determine if bacterial inoculants could eliminate E. coli O157:H7 (ECOL) in contaminated corn silages and if inoculants transferred antibacterial activity to silages. Chopped corn forage was ensiled in triplicate after treatment with:1) distilled water (control); 2) 5 x 105 cfu/g of ECOL (EC); 3) EC and 1 x 106 cfu/g of Pediococcus pentosaceus and freudenreichii (EC+BII); 4) EC and 1 x 106 cfu/g of Lactobacillus buchneri ((LB; EC+LB); 5)EC and 1 x 106 cfu/g of LB and P. pentosaceus (EC+B500). Silos were opened after 3, 7, 31, and 82 d and analyzed for pH and ECOL counts as well as VFA, lactate, and aerobic stability on d 82. By d 3, all silages had pH was <4 (SE=0.33; p=1) and pH did not increase subsequently; therefore ECOL was not detected in any silage. The Kirby-Bauer disc diffusion test showed that all pure cultures of inoculants had pH-independent antibacterial activity against ECOL but inoculated silages did not, suggesting that ECOL elimination was mediated by pH reduction. Inoculation with LB resulted in less lactate (SE=0.31; P < 0.05), more acetate (SE=0.35; P < 0.05), and greater aerobic stability (SE=7.1; P < 0.05) versus control. Day-82 silages were reinoculated with EC at silo opening (immediate) or after 144 h of exposure (delay) and ECOL were enumerated 24 h later. All immediately reinoculated silages had low pH values (<4) and no ECOL 24 h later. Control, EC, and EC+BII silages reinoculated after the delay had relatively high pH values (4.71, 5.67, and 6.03) (SE=0.74; P < 0.05) and ECOL counts (2.87, 6.73, and 6.87 log cfu/g) (SE=1.4; P < 0.05), whereas those treated with LB had low pH values (<4) and undetectable (EC+B500) or low ECOL counts b(1.9, cfu/g: EC-LB). Inoculants did not enhance elimination of ECOL during ensiling, but L. buchneri inoculants increased stability and eliminated or inhibited ECOL in aerobically exposed silages. (author)

  19. Bacterial indole-3-acetic acid production: a key mediator of plant-microbe interactions between Phaseolus vulgaris and the foliar epiphyte Pantoea agglomerans 299R

    OpenAIRE

    Powell, Tracy Kathleen

    2011-01-01

    The phyllosphere epiphyte Pantoea agglomerans 299R synthesizes indole-3-acetic acid (IAA), an important plant hormone. IAA production was previously shown to confer a small but significant fitness advantage to Pa299R cells inoculated onto bean (Phaseolus vulgaris) leaves, but the mechanism by which bacterial IAA exerts this effect is unknown. In this work, we investigated several hypotheses regarding how bacterial IAA enhances the growth and survival of leaf epiphytic microbes such as Pa299R....

  20. Homoserine lactones: Do plants really listen to bacterial talk?

    OpenAIRE

    Klein, Ilona; von Rad, Uta; Durner, Jörg

    2009-01-01

    The bacterial quorum sensing signals N-acyl-L-homoserine lactones (AHL) enable bacterial cells to regulate gene expression depending on population density, which eventually leads to invasion of hosts. Only little is known about the molecular ways of plants reacting to these bacterial signals. Recently, we showed that the contact of Arabidopsis thaliana roots with N-hexanoyl-DL-homoserine-lactone (HHL) resulted in distinct transcriptional changes in roots and shoots, respectively. In addition,...

  1. Growth, yield and physiology of Verticillium-inoculated pepper plants treated with ATAD and composted sewage sludge

    OpenAIRE

    Pascual, I. (I.); Azcona, I.; Morales, F.; Aguirreolea, J.; Sanchez-Diaz, M. (Manuel)

    2009-01-01

    A greenhouse experiment was conducted to investigate the impact of sanitized sewage sludges, ATAD (aerobic thermophilic autothermic digestion) and composted, on Verticillium-induced wilt in pepper plants (Capsicum annuum L. cv. Piquillo). Two doses of ATAD (15 and 30% v/v) and three of composted sludge (15, 30 and 45% v/v) were applied to a peat-based potting mix. Unamended substrate was included as control. Half of the plants were inoculated with V. dahliae, whereas the other half remained n...

  2. 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.

    Science.gov (United States)

    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

  3. Influence of biochar, mycorrhizal inoculation, and fertilizer rate on growth and flowering of Pelargonium (Pelargonium zonale L.) plants.

    Science.gov (United States)

    Conversa, Giulia; Bonasia, Anna; Lazzizera, Corrado; Elia, Antonio

    2015-01-01

    Peat is the most common substrate used in nurseries despite being a very expensive and a non-renewable material. Peat replacement with biochar could be a sound environmental practice, as it is produced from waste biomass, but evaluation of biochar as a potting substrate is needed. Ratios of peat:biochar of 100:0, 70:30, 30:70 (BC0, BC30, and BC70, respectively), two fertilizer rates (FERT1, FERT2), and arbuscular mycorrhizal fungi (AMF) inoculation were tested on potted Pelargonium plants. Plant growth, flowering, bio-physiological and nutritional responses, and root mycorrhization were evaluated. The BC30 mixture did not affect plant growth compared with pure peat. However, BC30 in combination with FERT2 treatment was more effective in enhancing nitrogen (N) and chlorophyll (CHL) leaf concentrations, and leaf and flower numbers. The BC70 mixture depressed plant growth, flowering traits, and root mycorrhization. Leaf N concentration was below the sufficiency range reported for Pelargonium growth. Leaf concentration of phosphorous (P) was adequate in pure peat and in BC30 but it dropped close to sub-optimal values in BC70. The pH value of the mixtures lowered P availability, though in BC30 the mycorrhizal activity could have allowed adequate P plant uptake. In BC70 plants, the deficiency of both N and P might be a reason for the observed growth reduction. The inoculation of the substrate with selected AMF improved plant growth (higher dry biomass, greater floral clusters, larger and more abundant leaves) and quality resulting in unstressed (lower electrolyte leakage and higher relative water content values) and greener leaves (low L(∗) and C(∗), high CHL content) and in more intensely colored flowers. We conclude that biochar can be applied in nursery/potted plant production provided that the proportion in the peat mixture does not exceed 30%. Furthermore, AMF inoculation contributed to achieving the best plant performance in 30% biochar amended medium. PMID

  4. Influence of biochar, mycorrhizal inoculation, and fertilizer rate on growth and flowering of Pelargonium (Pelargonium zonale L.) plants

    OpenAIRE

    Conversa, Giulia; Bonasia, Anna; Lazzizera, Corrado; Elia, Antonio

    2015-01-01

    Peat is the most common substrate used in nurseries despite being a very expensive and a non-renewable material. Peat replacement with biochar could be a sound environmental practice, as it is produced from waste biomass, but evaluation of biochar as a potting substrate is needed. Ratios of peat:biochar of 100:0, 70:30, 30:70 (BC0, BC30, and BC70, respectively), two fertilizer rates (FERT1, FERT2), and arbuscular mycorrhizal fungi (AMF) inoculation were tested on potted Pelargonium plants. Pl...

  5. [Role of Bacterial Adhesin RAPA1 in Formation of Efficient Symbiosis of Rhizobium leguminosarum with Bean Plants].

    Science.gov (United States)

    Nigmatullina, L R; Lavina, A M; Vershinina, Z R; Baimiev, Al Kh

    2015-01-01

    Bacterial adhesins, the proteins responsible for attachment of plant growth-promoting rhizobacteria to plant roots, are involved in formation of stable associative symbioses. In the present work enhanced expression of the rapA1 adhesin gene in Rhizobium leguminosarum PVu5 was shown to improve the efficiency of nodulation on bean roots inoculated with the modified strain. The rapA1 gene was cloned into the pJN105Turbo plasmid, this construct was used for transformation of R. leguminosarum PVu5, bean plants were inoculated by this transgenic strain, and efficiency of root nodule formation was determined. In the plants treated with rapA1-transgenic rhizobia, the number of root nodules was on average two times higher than in the plants inoculated with the original strain. Aggregation of R. leguminosarum was achieved when the rapA1 gene expression was enhanced either in rhizobia or in the co-cultured modified strain E. coli pJN105TurboRapA1. PMID:26964360

  6. Influence of Nitrogen Sources and Plant Growth-Promoting Rhizobacteria Inoculation on Growth, Crude Fiber and Nutrient Uptake in Squash (Cucurbita moschata Duchesne ex Poir. Plants

    Directory of Open Access Journals (Sweden)

    Alice I. TCHIAZE

    2016-06-01

    Full Text Available Plant growth promoting rhizobacteria (PGPR, B have immense potential application in sustainable agriculture as ecofriendly biofertilizers and biopesticides. In this study, the effects of three nitrogen (N sources (NO3-, NH4+ and NO3NH4 and PGPR on growth, crude fiber and nutrient uptake were investigated in squash plants. Some growth parameters [root dry weight (RDW, shoot dry weight (SDW, total plant dry weight (PDW, number of leaves (NL, shoot length (SL, stem diameter (SD and number of ramifications (NR], crude fiber (cellulose content and nutrient uptake (N, P, K, Ca, Mg, Na, Fe, Cu, Mn and Zn were determined. Application of NO3-,NH4+ or NO3NH4 singly or in combination with PGPR inoculation led to a significant increase in RDW, SDW, PDW, NL, SL, SD and NR. Na, Cu and Zn contents, on the contrary, decreased in inoculated treated plants while no significant differences were recorded in cellulose contents (CE of leaves except in plants fed with NO3-. The leaf CE content ranged from 12.58 to 13.67%. The plants supplied with NO3+B, NH4+B and NO3NH4+B showed significantly higher plant biomass and accumulation of N, P, K and Mn concentrations in leaves compared to all other treatments. These results suggest that specific combinations of PGPR with NO3-, NH4+ or NO3NH4 fertilizers can be considered as efficient alternative biofertilizers to improve significantly the squash growth and nutrient uptake.

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

    International Nuclear Information System (INIS)

    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. 15N recovery by wheat plants was enhanced by bacterial inoculation as well as water salinity levels did. (Author)

  8. 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.

    Science.gov (United States)

    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%). PMID:24148195

  9. 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)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Munier-Lamy, C. [LIMOS, UMR 7137 CNRS-Nancy University, Faculty of Sciences, P.O. Box 239, F-54506 Vandoeuvre-les-Nancy Cedex (France)], E-mail: colette.munier@limos.uhp-nancy.fr; Deneux-Mustin, S. [LIMOS, UMR 7137 CNRS-Nancy University, Faculty of Sciences, P.O. Box 239, F-54506 Vandoeuvre-les-Nancy Cedex (France); Mustin, C. [LIMOS, UMR 7137 CNRS-Nancy University, Faculty of Sciences, P.O. Box 239, F-54506 Vandoeuvre-les-Nancy Cedex (France)], E-mail: christian.mustin@limos.uhp-nancy.fr; Merlet, D. [LIMOS, UMR 7137 CNRS-Nancy University, Faculty of Sciences, P.O. Box 239, F-54506 Vandoeuvre-les-Nancy Cedex (France)], E-mail: denis.merlet@limos.uhp-nancy.fr; Berthelin, J. [LIMOS, UMR 7137 CNRS-Nancy University, Faculty of Sciences, P.O. Box 239, F-54506 Vandoeuvre-les-Nancy Cedex (France)], E-mail: jacques.berthelin@limos.uhp-nancy.fr; Leyval, C. [LIMOS, UMR 7137 CNRS-Nancy University, Faculty of Sciences, P.O. Box 239, F-54506 Vandoeuvre-les-Nancy Cedex (France)], E-mail: corinne.leyval@limos.uhp-nancy.fr

    2007-10-15

    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.

  11. Bacterial endosymbionts of plant-parasitic nematodes

    Science.gov (United States)

    Several groups of bacteria have been reported as endosymbionts of various orders of nematodes including the filarial nematodes (Brugia malayi, Wucheria bancrofti and Onchocerca volvulus (Spiruida)), the entomopathogenic nematodes (Steinernema spp., and Heterorhabditis spp. (Rhabditida)), and plant-p...

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

    Directory of Open Access Journals (Sweden)

    Xiang Gao

    Full Text Available BACKGROUND: 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. PRINCIPAL FINDINGS: 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. CONCLUSIONS: 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.

  13. Effects of Inoculation with Phosphate-solubilizing Bacteriaon Plant Growth and Phosphorus Uptake of Citrus Budlings%溶磷菌对柑桔嫁接苗磷素营养及生长发育的影响

    Institute of Scientific and Technical Information of China (English)

    牛廷香; 邓烈; 易时来; 简仙水; 赵旭阳; 王亮; 何绍兰

    2011-01-01

    Two inorganic phosphate-solubilizing bacterial strains and two organic solubilizing bacterial strains were used separately to inoculate the soils growing potted citrus budlings to investigate the effects of these phosphate-solubilizing bacteria (PSBs) on the phosphorus levels in soils and plants,and the growth of citrus budlings. The results showed that inoculation of both non-sterilized and sterilized soils with PSBs significantly increased the total P content in the above ground parts of the seedlings. In leaves, N, Fe, Cu levels were also significantly increased and the increase in Mg content was even more significant, when compared with controls. The plant heights, stem diameters and the above ground fresh and dry weights of the budlings were significantly increased by soil inoculation of PSBs. Inoculation with inorganic PSBs in both sterilized or non-sterilized soils showed a significant improvement in plant P nutrition and growth while inoculation with organic PSBs in nonsterilized soils had better improvement effects.%将扩繁的无机溶磷菌和有机溶磷菌各2株,分别接种于灭菌和非灭菌的盆栽枳橙Poncirus trifoliata×Citrus sinensis cv.Carrizo Citrange砧塔罗科血橙C.sinensis cv.Tarocco Blood orange嫁接苗土壤中,研究溶磷菌对植株磷营养及其生长发育的影响.结果表明,供试菌株接种于非灭菌和灭菌土壤中,植株地上部总磷含量均显著增加,同时氮、铁、铜以及镁含量亦显著增加.土壤施用溶磷菌的柑桔嫁接苗株高、茎粗及地上部分生物量等显著增加.无论土壤灭菌与否,无机溶磷菌对改善植株磷素营养和促进苗木生长均有明显促进作用,而有机溶磷菌接种于非灭菌土中其效应更为明显.

  14. Bacterial anoxygenic photosynthesis on plant leaf surfaces

    Czech Academy of Sciences Publication Activity Database

    Atamna-Ismaeel, N.; Finkel, O.; Glaser, F.; von Mering, Ch.; Vorholt, J. A.; Koblížek, Michal; Belkin, S.; Béja, O.

    2012-01-01

    Roč. 4, č. 2 (2012), s. 209-216. ISSN 1758-2229 R&D Projects: GA MŠk(CZ) ED2.1.00/03.0110; GA ČR GAP501/10/0221 Institutional support: RVO:61388971 Keywords : phyllosphere * plant * phyllosphere Subject RIV: EE - Microbiology, Virology Impact factor: 2.708, year: 2012

  15. Community structure of actively growing bacterial populations in plant pathogen suppressive soil

    NARCIS (Netherlands)

    Hjort, K.; Lembke, A.; Speksnijder, A.G.C.L.; Smalla, K.; Jansson, J.K.

    2007-01-01

    The bacterial community in soil was screened by using various molecular approaches for bacterial populations that were activated upon addition of different supplements. Plasmodiophora brassicae spores, chitin, sodium acetate, and cabbage plants were added to activate specific bacterial populations a

  16. Cultivation-based and molecular assessment of bacterial diversity in the rhizosheath of wheat under different crop rotations

    OpenAIRE

    Muhammad Tahir; M Sajjad Mirza; Sohail Hameed; Dimitrov, Mauricio R.; Hauke Smidt

    2015-01-01

    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 lengt...

  17. Dynamic Development of Aphelenchoides besseyi on Rice Plant by Artificial Inoculation in the Greenhouse

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A study was done on the relationship between Aphelenchoides besseyi and the symptoms of small grains and erect panicles. This is an important rice disease in Jiangsu Province, China. A. besseyi was extracted from small grains and erect panicles and cultured artificially, and then inoculated into bud and leaf sheaths of seedlings of two Oryza sativa cultivars, namely Zhendao 2 and Wuyunjing 7 in a greenhouse. The effect on rice growth, in particular the small grains and erect panicles, was revealed by the extent of the disease, seed expansion stages, nematode load, and nematode mortality. In contrast to healthy seedlings, the height, length, and the numbers of spikelets of unhealthy panicles of Zhendao 2 were decreased by 6.7, 16.4, and 13.5%, respectively. Before anthesis, nematodes were attracted to the leaf sheath and apical meristem, nematode load increased by 40%; after anthesis, nematodes occurred in spikelets principally and the number increased by 90.8%. The percentages of infected seeds and nematode load were highest in plump seeds and lowest in empty seeds. Nematode mortality on grain with normal endosperm was lower than seeds with abnormal endosperm. Results indicated that A. besseyi was the pathogen in rice with the symptoms of small grains and erect panicles. Wuyunjing 7 manifests only the small grains and erect panicles symptoms and not the symptoms of leaf white-tip. These symptoms of small grains and erect panicles are new symptom records for the disease caused by A. besseyi on rice.

  18. Bacterial Gibberellins Induce Systemic Resistance of Plants

    OpenAIRE

    I. N. FEKLISTOVA; I. A. GRINEVA; T. L. SKAKUN; L. E. SADOVSKAYA

    2014-01-01

    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 ...

  19. Cultivation-based and molecular assessment of bacterial diversity in the rhizosheath of wheat under different crop rotations

    NARCIS (Netherlands)

    Tahir, Muhammad; Mirza, M.S.; Hameed, Sohail; Rocha Dimitrov, Mauricio; Smidt, Hauke

    2015-01-01

    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 inc

  20. Bacterial Outer Membrane Vesicles Induce Plant Immune Responses.

    Science.gov (United States)

    Bahar, Ofir; Mordukhovich, Gideon; Luu, Dee Dee; Schwessinger, Benjamin; Daudi, Arsalan; Jehle, Anna Kristina; Felix, Georg; Ronald, Pamela C

    2016-05-01

    Gram-negative bacteria continuously pinch off portions of their outer membrane, releasing membrane vesicles. These outer membrane vesicles (OMVs) are involved in multiple processes including cell-to-cell communication, biofilm formation, stress tolerance, horizontal gene transfer, and virulence. OMVs are also known modulators of the mammalian immune response. Despite the well-documented role of OMVs in mammalian-bacterial communication, their interaction with plants is not well studied. To examine whether OMVs of plant pathogens modulate the plant immune response, we purified OMVs from four different plant pathogens and used them to treat Arabidopsis thaliana. OMVs rapidly induced a reactive oxygen species burst, medium alkalinization, and defense gene expression in A. thaliana leaf discs, cell cultures, and seedlings, respectively. Western blot analysis revealed that EF-Tu is present in OMVs and that it serves as an elicitor of the plant immune response in this form. Our results further show that the immune coreceptors BAK1 and SOBIR1 mediate OMV perception and response. Taken together, our results demonstrate that plants can detect and respond to OMV-associated molecules by activation of their immune system, revealing a new facet of plant-bacterial interactions. PMID:26926999

  1. Valor nutritivo de silagens de milho (Zea mays L. produzidas com inoculantes enzimo-bacterianos Nutritive value of corn silage (Zea mays L. produced with enzymatic-bacterial inoculants

    Directory of Open Access Journals (Sweden)

    Karina Dosualdo Rocha

    2006-04-01

    valor para a silagem tratada com o inoculante Biomax (66,0%. A adição de inoculantes à planta de milho não promoveu alterações na composição química e no consumo dos nutrientes das silagens.Two inoculated corn silage experiments are reported. In the first one, pH value, ammonia nitrogen in total nitrogen (N-NH3/Total N, chemical composition and in vitro drymatter digestibility of corn silages with or without enzymatic-bacterial inoculants were evaluated in laboratory silos. A 6 x 3 factorial arrangement of treatments, with six fermentation periods (01, 03, 07, 14, 28 and 56 days x three inoculants (control and two commercial inoculants: Maize All (Alltech of Brazil and Biomax (Christian Hansen was used in a completely randomized design, with three replications. Effect of the inoculant × fermentation period interaction was detected on silages DM content, larger values corresponding to the inoculated silages, independent of the fermentation period. Inoculants favored silage crude protein (CP concentration, the smallest value (6.23% being observed in control silage. It was also observed an effect of fermentation period on neutral detergent fiber (NDF and acid detergent fiber (ADF, which decreased by 0.302353 and 0.063321 units/fermentation day, respectively. The in vitro dry matter digestibility increased with fermentation period, with increments of 0.0546305 unit/day. In the second experiment, intake and total apparent digestibility of silage nutrients were evaluated with rams. Eighteen castrated adult rams were assigned to three treatments, in a randomized blocks design, with six replicates. The diets consisted of 90:10 forage to concentrate ratio in a dry matter basis. The intake of nutrients was not influenced by the experimental diets, being observed mean values of 1.26; 0.14 and 0.84 kg/day for dry matter (DM, crude protein intake (CP and total digestive nutrients (TDN intake, respectively. An inoculant effect was observed on CP apparent digestibility

  2. 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.

  3. Bacterial-Plant-Interactions: Approaches to Unravel the Biological Function of Bacterial Volatiles in the Rhizosphere.

    Science.gov (United States)

    Kai, Marco; Effmert, Uta; Piechulla, Birgit

    2016-01-01

    Rhizobacteria produce an enormous amount of volatile compounds, however, the function of these metabolites is scarcely understood. Investigations evaluating influences on plants performed in various laboratories using individually developed experimental setups revealed different and often contradictory results, e.g., ranging from a significant plant growth promotion to a dramatic suppression of plant development. In addition to these discrepancies, these test systems neglected properties and complexity of the rhizosphere. Therefore, to pursue further investigations of the role of bacterial volatiles in this underground habitat, the applied methods have to simulate its natural characteristics as much as possible. In this review, we will describe and discuss pros and cons of currently used bioassays, give insights into rhizosphere characteristics, and suggest improvements for test systems that would consider in natura conditions and would allow gaining further knowledge of the potential function and significance of rhizobacterial volatiles in plant life. PMID:26903987

  4. Improved plant growth and Zn accumulation in grains of rice (Oryza sativa L.) by inoculation of endophytic microbes isolated from a Zn Hyperaccumulator, Sedum alfredii H.

    Science.gov (United States)

    Wang, Yuyan; Yang, Xiaoe; Zhang, Xincheng; Dong, Lanxue; Zhang, Jie; Wei, Yanyan; Feng, Ying; Lu, Lingli

    2014-02-26

    This study is to investigate the possibility of zinc (Zn) biofortification in the grains of rice (Oryza sativa L.) by inoculation of endophytic strains isolated from a Zn hyperaccumulator, Sedum alfredii Hance. Five endophytic strains, Burkholderia sp. SaZR4, Burkholderia sp. SaMR10, Sphingomonas sp. SaMR12, Variovorax sp. SaNR1, and Enterobacter sp. SaCS20, isolated from S. alfredii, were inoculated in the roots of Japonica rice Nipponbare under hydroponic condition. Fluorescence images showed that endophytic strains successfully colonized rice roots after 72 h. Improved root morphology and plant growth of rice was observed after inoculation with endophytic strains especially SaMR12 and SaCS20. Under hydroponic conditions, endophytic inoculation with SaMR12 and SaCS20 increased Zn concentration by 44.4% and 51.1% in shoots, and by 73.6% and 83.4% in roots, respectively. Under soil conditions, endophytic inoculation with SaMR12 and SaCS20 resulted in an increase of grain yields and elevated Zn concentrations by 20.3% and 21.9% in brown rice and by 13.7% and 11.2% in polished rice, respectively. After inoculation of SaMR12 and SaCS20, rhizosphere soils of rice plants contained higher concentration of DTPA-Zn by 10.4% and 20.6%, respectively. In situ micro-X-ray fluorescence mapping of Zn confirmed the elevated Zn content in the rhizosphere zone of rice treated with SaMR12 as compared with the control. The above results suggested that endophytic microbes isolated from S. alfredii could successfully colonize rice roots, resulting in improved root morphology and plant growth, increased Zn bioavailability in rhizosphere soils, and elevated grain yields and Zn densities in grains. PMID:24447030

  5. Seeds with high molybdenum concentration improved growth and nitrogen acquisition of rhizobium-inoculated and nitrogen-fertilized common bean plants

    Directory of Open Access Journals (Sweden)

    Fernanda Fátima Delgado Almeida

    2013-04-01

    Full Text Available Seeds of common bean (Phaseolus vulgaris with high molybdenum (Mo concentration can supply Mo plant demands, but to date no studies have concomitantly evaluated the effects of Mo-enriched seeds on plants inoculated with rhizobia or treated with N fertilizer. This work evaluated the effects of seed Mo on growth and N acquisition of bean plants fertilized either by symbiotic N or mineral N, by measuring the activities of nitrogenase and nitrate reductase and the contribution of biological N2 fixation at different growth stages. Seeds enriched or not with Mo were sown with two N sources (inoculated with rhizobia or fertilized with N, in pots with 10 kg of soil. In experiment 1, an additional treatment consisted of Mo-enriched seeds with Mo applied to the soil. In experiment 2, the contribution of N2 fixation was estimated by 15N isotope dilution. Common bean plants grown from seeds with high Mo concentration flowered one day earlier. Seeds with high Mo concentration increased the leaf area, shoot mass and N accumulation, with both N sources. The absence of effects of Mo application to the soil indicated that Mo contents of Mo-enriched seeds were sufficient for plant growth. Seeds enriched with Mo increased nitrogenase activity at the vegetative stage of inoculated plants, and nitrate reductase activity at late growth stages with both N sources. The contribution of N2 fixation was 17 and 61 % in plants originating from low- or high-Mo seeds, respectively. The results demonstrate the benefits of sowing Mo-enriched seeds on growth and N nutrition of bean plants inoculated with rhizobia or fertilized with mineral N fertilizer.

  6. 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

  7. 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

  8. Yield and nutrient content of Bell Pepper pods from plants developed from seedlings inoculated, or not, with microorganisms

    Science.gov (United States)

    The effectiveness of microorganisms applied in production of vegetable transplants has had mixed results. Bell pepper (Capsicum annuum L.) transplants were produced in a greenhouse using organic methods and the organic certified potting mix was either not inoculated or inoculated with beneficial ba...

  9. Bacterial secondary production on vascular plant detritus: relationships to detritus composition and degradation rate.

    OpenAIRE

    Moran, M.A. (María Asunción); Hodson, R E

    1989-01-01

    Bacterial production at the expense of vascular plant detritus was measured for three emergent plant species (Juncus effusus, Panicum hemitomon, and Typha latifolia) degrading in the littoral zone of a thermally impacted lake. Bacterial secondary production, measured as tritiated thymidine incorporation into DNA, ranged from 0.01 to 0.81 microgram of bacterial C mg of detritus-1 day-1. The three plant species differed with respect to the amount of bacterial productivity they supported per mil...

  10. Deciphering the bacterial microbiome of citrus plants in response to 'Candidatus Liberibacter asiaticus'-infection and antibiotic treatments.

    Directory of Open Access Journals (Sweden)

    Muqing Zhang

    Full Text Available The bacterial microbiomes of citrus plants were characterized in response to 'Candidatus Liberibacter asiaticus' (Las-infection and treatments with ampicillin (Amp and gentamicin (Gm by Phylochip-based metagenomics. The results revealed that 7,407 of over 50,000 known Operational Taxonomic Units (OTUs in 53 phyla were detected in citrus leaf midribs using the PhyloChip™ G3 array, of which five phyla were dominant, Proteobacteria (38.7%, Firmicutes (29.0%, Actinobacteria (16.1%, Bacteroidetes (6.2% and Cyanobacteria (2.3%. The OTU62806, representing 'Candidatus Liberibacter', was present with a high titer in the plants graft-inoculated with Las-infected scions treated with Gm at 100 mg/L and in the water-treated control (CK1. However, the Las bacterium was not detected in the plants graft-inoculated with Las-infected scions treated with Amp at 1.0 g/L or in plants graft-inoculated with Las-free scions (CK2. The PhyloChip array demonstrated that more OTUs, at a higher abundance, were detected in the Gm-treated plants than in the other treatment and the controls. Pairwise comparisons indicated that 23 OTUs from the Achromobacter spp. and 12 OTUs from the Methylobacterium spp. were more abundant in CK2 and CK1, respectively. Ten abundant OTUs from the Stenotrophomonas spp. were detected only in the Amp-treatment. These results provide new insights into microbial communities that may be associated with the progression of citrus huanglongbing (HLB and the potential effects of antibiotics on the disease and microbial ecology.

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

    Science.gov (United States)

    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. PMID:22625420

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

    Science.gov (United States)

    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. PMID:26909087

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

    Directory of Open Access Journals (Sweden)

    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.

  14. Bacterial endophyte Sphingomonas sp. LK11 produces gibberellins and IAA and promotes tomato plant growth.

    Science.gov (United States)

    Khan, Abdul Latif; Waqas, Muhammad; Kang, Sang-Mo; Al-Harrasi, Ahmed; Hussain, Javid; Al-Rawahi, Ahmed; Al-Khiziri, Salima; Ullah, Ihsan; Ali, Liaqat; Jung, Hee-Young; Lee, In-Jung

    2014-08-01

    Plant growth promoting endophytic bacteria have been identified as potential growth regulators of crops. Endophytic bacterium, Sphingomonas sp. LK11, was isolated from the leaves of Tephrosia apollinea. The pure culture of Sphingomonas sp. LK11 was subjected to advance chromatographic and spectroscopic techniques to extract and isolate gibberellins (GAs). Deuterated standards of [17, 17-(2)H2]-GA4, [17, 17-(2)H2]-GA9 and [17, 17-(2)H2]-GA20 were used to quantify the bacterial GAs. The analysis of the culture broth of Sphingomonas sp. LK11 revealed the existence of physiologically active gibberellins (GA4: 2.97 ± 0.11 ng/ml) and inactive GA9 (0.98 ± 0.15 ng/ml) and GA20 (2.41 ± 0.23). The endophyte also produced indole acetic acid (11.23 ± 0.93 μM/ml). Tomato plants inoculated with endophytic Sphingomonas sp. LK11 showed significantly increased growth attributes (shoot length, chlorophyll contents, shoot, and root dry weights) compared to the control. This indicated that such phyto-hormones-producing strains could help in increasing crop growth. PMID:24994010

  15. Novel components of leaf bacterial communities of field-grown tomato plants and their potential for plant growth promotion and biocontrol of tomato diseases.

    Science.gov (United States)

    Romero, Fernando M; Marina, María; Pieckenstain, Fernando L

    2016-04-01

    This work aimed to characterize potentially endophytic culturable bacteria from leaves of cultivated tomato and analyze their potential for growth promotion and biocontrol of diseases caused by Botrytis cinerea and Pseudomonas syringae. Bacteria were obtained from inner tissues of surface-disinfected tomato leaves of field-grown plants. Analysis of 16S rRNA gene sequences identified bacterial isolates related to Exiguobacterium aurantiacum (isolates BT3 and MT8), Exiguobacterium spp. (isolate GT4), Staphylococcus xylosus (isolate BT5), Pantoea eucalypti (isolate NT6), Bacillus methylotrophicus (isolate MT3), Pseudomonas veronii (isolates BT4 and NT2), Pseudomonas rhodesiae (isolate BT2) and Pseudomonas cichorii (isolate NT3). After seed inoculation, BT2, BT4, MT3, MT8, NT2 and NT6 were re-isolated from leaf extracts. NT2, BT2, MT3 and NT6 inhibited growth of Botrytis cinerea and Pseudomonas syringae pv. tomato in vitro, produced antimicrobial compounds and reduced leaf damage caused by B. cinerea. Some of these isolates also promoted growth of tomato plants, produced siderophores, the auxin indole-3-acetic and solubilized inorganic phosphate. Thus, bacterial communities of leaves from field-grown tomato plants were found to harbor potentially endophytic culturable beneficial bacteria capable of antagonizing pathogenic microorganisms and promoting plant growth, which could be used as biological control agents and biofertilizers/biostimulators for promotion of tomato plant growth. PMID:26654914

  16. Studies on the Origin of Plant Bacteriophages in an Artifcial Inoculation Condition%人T接种条件下植物病原细菌噬菌体来源的研究

    Institute of Scientific and Technical Information of China (English)

    涂立超; 成国英; 于大胜; 杨国桂

    2001-01-01

    对盆栽水稻采用针刺、喷雾、盆水等不同方法接种水稻细菌性条斑病病菌后,检测稻株发病和盆水中的噬菌体,结果表明:未接种稻细条病菌的处理中,无稻株发病,盆水中也未测到噬菌体;3种接种处理均可引致稻株发病,并先后在其盆水中检测到噬菌体,说明噬菌体与致病菌有密切的伴随关系。在采用叶面喷雾和盆水接种稻白叶枯自然组合菌株B-1和单细胞系菌株Ⅳ-16试验中,B-1处理后能引起稻株发病,且在盆水中测到噬菌体;而Ⅳ-16处理后虽引起稻株发病,但盆水中无噬菌体,结果表明:在人工接种条件下植物病原细菌噬菌体是由病菌中的溶原细胞传带而来的。%5 days after the leaves of rice plants in polythere bacins were inoculating with the suspention of Xanthomonas oryzae pv. oryzicola strain by needle-pricking, spraying and pouring it in rice basins' water, the percentages of diseased plants and the quantities of phages in the rice basins' water were checked up periodically. The results showed that three kinds of inoculation methods all succeeded in causing bacterial leaf streak (BLS), the bacteriophages were detected in the rice basins' water, while there were no diseased plants and phages in non-inoculated rice basins, which indicted there was a close companionate relationship between the pathogen and the phage. When the rice plants and the rice basins' water were inoculated with the natural composite strain of B-1 and the monocell colony strain of IV-16 of X. oryzae pv. oryzae, both the bacterial leaf blight (BLB) and phages were detected in the treatment with B-l, but altnough the BLB appeared on the rice plants and no phage was detected in the treatment with Ⅳ16,which suggested that the bacteriophages were be transmitted by the lysogenic cell (cells affected by temperate phages) among the composite strain cells in the artificial inoculation condition.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Inoculation of Pinus halepensis Mill. with selected ectomycorrhizal fungi improves seedling establishment 2 years after planting in a degraded gypsum soil.

    Science.gov (United States)

    Rincón, Ana; de Felipe, M R; Fernández-Pascual, M

    2007-12-01

    Vegetative inoculum of Amanita ovoidea (Bull.) Link and three isolates of Suillus collinitus (Fr.) Kuntze, as well as spore inoculum of Rhizopogon roseolus (Corda) Th. M. Fr. and S. collinitus, were evaluated for the production of Pinus halepensis Mill. in nursery and for the establishment of seedlings in a degraded gypsum soil. In nursery, most of the fungi significantly improved the height of seedlings and modified the accumulation of nutrients in needles. The percentage of ectomycorrhizas (ESR) per seedling ranged from 25 to 78%, depending on the fungi. One and 2 years after planting in the field, the survival of seedlings was significantly improved by inoculation with two isolates of S. collinitus and with spores of the same fungus. Inoculation with A. ovoidea had no significant effect on seedling survival, whilst R. roseolus caused a significant mortality of seedlings. Seedling height was significantly improved by inoculation with all fungi except R. roseolus and isolate CCMA-1 of S. collinitus. One year after planting, mycorrhization of control seedlings was negligible, and percentages of ESR were under 38% for the rest of treatments. In spring of the second year, seedlings in all treatments, including the control, became highly mycorrhizal (60-77% of ESR). Low ectomycorrhizal diversity (five morphotypes described) and seasonal variation on morphotype composition were detected 2 years after plantation. From a perspective of soil restoration management under limiting environmental conditions, nursery inoculation with selected fungi can be a key advantage for tree seedlings to surmount the initial transplant stress, assuring their establishment in the field. Our results emphasise the importance of selecting compatible fungal-host species combinations for nursery inoculation and sources of inoculum adapted to the environmental conditions of the transplantation site. PMID:17874144

  19. Tuber melanosporum: mating type distribution in a natural plantation and dynamics of strains of different mating types on the roots of nursery-inoculated host plants.

    Science.gov (United States)

    Rubini, Andrea; Belfiori, Beatrice; Riccioni, Claudia; Arcioni, Sergio; Martin, Francis; Paolocci, Francesco

    2011-02-01

    • In light of the recent finding that Tuber melanosporum, the ectomycorrhizal ascomycete that produces the most highly prized black truffles, is a heterothallic species, we monitored the spatial distribution of strains with opposite mating types (MAT) in a natural truffle ground and followed strain dynamics in artificially inoculated host plants grown under controlled conditions. • In a natural truffle ground, ectomycorrhizas (ECMs), soil samples and fruit bodies were sampled and genotyped to determine mating types. Simple sequence repeat (SSR) markers were also used to fingerprint ECMs and fruit bodies. The ECMs from nursery-inoculated host plants were analysed for mating type at 6 months and 19 months post-inoculation. • In open-field conditions, all ECMs from the same sampling site showed an identical mating type and an identical haploid genotype, based on SSR analysis. Interestingly, the gleba of fruit bodies always demonstrated the same genotype as the surrounding ECMs. Although root tips from nursery-grown plants initially developed ECMs of both mating types, a dominance of ECMs of the same MAT were found after several months. • The present study deepens our understanding of the vegetative and sexual propagation modes of T. melanosporum. These results are highly relevant for truffle cultivation. PMID:20964691

  20. Radiotracer study on phosphorus utilization as influenced by bacterial seed inoculation, farmyard manure and nitrogen fertilization in Triticum aestivum grown on Typic ustifluvents (saline phase)

    International Nuclear Information System (INIS)

    A field experiment was carried out in micro-plots using 32P labelled superphosphate with varying levels of nitrogen (0, 60, 80 and 120 kg ha-1). farmyard manure (0 and 20 t ha-l) and bio fertilizers (Azospirillum, Azotobacter and no inoculation). Results revealed that the application of P either alone or with FYM in the presence of increasing levels of nitrogen as well as different sources of bio-fertilizers enhanced grain and straw yield as well as total P uptake. Seed inoculated with bio fertilizers or individual application of N also enhanced the yield, total P uptake and fertilizer P utilization. On the contrary, radiochemical analysis showed some depletion in per cent phosphorus derived from fertilizer (% Pdff) when FYM was applied in association with P. However, inoculation of seeds with bio fertilizers enhanced it. P utilization on the other hand, increased considerably in presence of N, P and FYM particularly when seeds were inoculated with both the inoculants. Moreover, yield and utilization of P was higher in favour of Azotobacter compared to Azospirillum. (author)

  1. Effect of inoculation of Pseudomonas fluorescens strain FY32 on some traits in canola cultivars under salt stress in hydroponic system

    Directory of Open Access Journals (Sweden)

    2015-06-01

    Full Text Available Plant growth promoting rhizobacteria are known as an alternative to chemical fertilizers, which are able to reduce the harmful effects of non-biological stresses such as salinity and increase soil fertility and crop production. This study was conducted to investigate the effect of inoculation of Pseudomonas fluorescens strain FY32 on a number of morphological characters in canola cultivars under salt stress. Thereby, a split split-plot design with three replications was applied in hydroponic cultivation system. Six bacterial inoculated (Pseudomonas flourescens FY32 and non-inoculated canola cultivars were subjected to sodium chloride salt stress at three levels (0, 150 and 300 mM. Based on the ANOVA results, inoculation effects under different salinity levels on canola cultivars, compared to non-inoculated treatments, were statistically significant on plant fresh weight, dry weight of leaf, stem and total plant, leaf area and root length. Also, three-way interaction effects of salinity, bacteria and cultivar on plant height and root volume were significant (P<0.01. Sodium, potassium and proline concentration in leaves and roots of inoculated plants had significant difference with non-inoculated plants at different levels of salinity. The highest rate of proline and potassium ion was observed in canola cultivars inoculated with Pseudomonas fluorescens under both salinity levels. It can be concluded that inoculation of canola plants with Pseudomonas flourescense (containing ACC- deaminase gene could improve their growth and development in case of salinity stress.

  2. 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. PMID:24665686

  3. New inoculants on maize silage fermentation

    OpenAIRE

    Fábia Giovana do Val de Assis; Carla Luiza da Silva Ávila; José Cardoso Pinto; Rosane Freitas Schwan

    2014-01-01

    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 prot...

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

    OpenAIRE

    Giovanna eVisioli; Teofilo eVamerali; Monica eMattarozzi; Lucia eDramis; Anna Maria Sanangelantoni

    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 spe...

  5. Effects of Plant Biomass, Plant Diversity, and Water Content on Bacterial Communities in Soil Lysimeters: Implications for the Determinants of Bacterial Diversity▿ †

    OpenAIRE

    Zul, Delita; Denzel, Sabine; Kotz, Andrea; Overmann, Jörg

    2007-01-01

    Soils may comprise tens of thousands to millions of bacterial species. It is still unclear whether this high level of diversity is governed by functional redundancy or by a multitude of ecological niches. In order to address this question, we analyzed the reproducibility of bacterial community composition after different experimental manipulations. Soil lysimeters were planted with four different types of plant communities, and the water content was adjusted. Group-specific phylogenetic finge...

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

    Directory of Open Access Journals (Sweden)

    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.

  7. Bacterial microcompartments as metabolic modules for plant synthetic biology.

    Science.gov (United States)

    Gonzalez-Esquer, C Raul; Newnham, Sarah E; Kerfeld, Cheryl A

    2016-07-01

    Bacterial microcompartments (BMCs) are megadalton-sized protein assemblies that enclose segments of metabolic pathways within cells. They increase the catalytic efficiency of the encapsulated enzymes while sequestering volatile or toxic intermediates from the bulk cytosol. The first BMCs discovered were the carboxysomes of cyanobacteria. Carboxysomes compartmentalize the enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) with carbonic anhydrase. They enhance the carboxylase activity of RuBisCO by increasing the local concentration of CO2 in the vicinity of the enzyme's active site. As a metabolic module for carbon fixation, carboxysomes could be transferred to eukaryotic organisms (e.g. plants) to increase photosynthetic efficiency. Within the scope of synthetic biology, carboxysomes and other BMCs hold even greater potential when considered a source of building blocks for the development of nanoreactors or three-dimensional scaffolds to increase the efficiency of either native or heterologously expressed enzymes. The carboxysome serves as an ideal model system for testing approaches to engineering BMCs because their expression in cyanobacteria provides a sensitive screen for form (appearance of polyhedral bodies) and function (ability to grow on air). We recount recent progress in the re-engineering of the carboxysome shell and core to offer a conceptual framework for the development of BMC-based architectures for applications in plant synthetic biology. PMID:26991644

  8. Copper-resistant bacteria reduces oxidative stress and uptake of copper in lentil plants: potential for bacterial bioremediation.

    Science.gov (United States)

    Islam, Faisal; Yasmeen, Tahira; Ali, Qasim; Mubin, Muhammad; Ali, Shafaqat; Arif, Muhammad Saleem; Hussain, Sabir; Riaz, Muhammad; Abbas, Farhat

    2016-01-01

    For effective microbe-assisted bioremediation, metal-resistant plant growth-promoting bacteria (PGPB) must facilitate plant growth by restricting excess metal uptake in plants, leading to prevent its bio-amplification in the ecosystem. The aims of our study were to isolate and characterize copper (Cu)-resistant PGPB from waste water receiving contaminated soil. In addition, we investigated the phytotoxic effect of copper on the lentil plants inoculated with copper-resistant bacteria Providencia vermicola, grown in copper-contaminated soil. Copper-resistant P. vermicola showed multiple plant growth promoting characteristics, when used as a seed inoculant. It protected the lentil plants from copper toxicity with a considerable increase in root and shoot length, plant dry weight and leaf area. A notable increase in different gas exchange characteristics such as A, E, C i , g s , and A/E, as well as increase in N and P accumulation were also recorded in inoculated plants as compared to un-inoculated copper stressed plants. In addition, leaf chlorophyll content, root nodulation, number of pods, 1,000 seed weight were also higher in inoculated plants as compared with non-inoculated ones. Anti-oxidative defense mechanism improved significantly via elevated expression of reactive oxygen species -scavenging enzymes including ascorbate peroxidase, superoxide dismutase, catalase, and guaiacol peroxidase with alternate decrease in malondialdehyde and H2O2 contents, reduced electrolyte leakage, proline, and total phenolic contents suggesting that inoculation of P. vermicola triggered heavy metals stress-related defense pathways under copper stress. Overall, the results demonstrated that the P. vermicola seed inoculation confer heavy metal stress tolerance in lentil plant which can be used as a potent biotechnological tool to cope with the problems of copper pollution in crop plants for better yield. PMID:26387695

  9. Spatiotemporal colonization of Xyllela fastidiosa in its vector supports two types of egestion in the inoculation mechanism of foregut-borne plant pathogens

    Science.gov (United States)

    The bacterial agent that causes Pierce’s disease of grapevine, Xylella fastidiosa, is the only known arthropod-transmitted prokaryotic plant pathogen that does not circulate in the vector’s hemolymph. Instead, bacteria are foregut-borne and semi-persistent, i.e. bacteria colonize cuticular surface...

  10. Effectiveness of mycorrhizal inoculation in the nursery on root colonization, growth, and nutrient uptake of aspen and balsam poplar

    Energy Technology Data Exchange (ETDEWEB)

    Quoreshi, A.M.; Khasa, D.P. [Symbiotech Research Inc. 201, 509-11 Avenue, Nisku, AB (Canada); Forest Biology Research Centre, University of Laval, Quebec (Canada)

    2008-05-15

    Aspen and balsam poplar seedlings were inoculated with six species of ectomycorrhizal fungi (Hebeloma longicaudum, Laccaria bicolor, Paxillus involutus, Pisolithus tinctorius, Rhizopogon vinicolor, and Suillus tomentosus), one species of endomycorrhizal fungus (Glomus intraradices), two species of bacteria (Agrobacterium sp. and Burkholderia cepacia), treated with a growth hormone (SR3), and co-inoculated with a combination of Paxillus and Burkholderia. The seedlings were grown in a greenhouse under three different fertility regimes. Bacterial inoculation alone did not affect seedling growth and nutrition as observed when co-inoculated with ectomycorrhizal fungus. The biomass and root collar diameter of aspen and balsam poplar were significantly increased when adequate mycorrhizas are formed and more prominent when co-inoculated with P. involutus and B. cepacia and grown at the 67% fertilizer level. Except for R. vinicolor and S. tomentosus, the other four species of ectomycorrhizal fungi and G. intraradices formed symbiotic associations with both plant species. Both ectomycorrhizal and endomycorrhizal colonization were observed at all fertilizer levels and fertilizer applications did not affect the colonization rates. Nitrogen and phosphorus concentrations were significantly improved in both aspen and balsam poplar compared with control only when co-inoculated with P. involutus and B. cepacia. However, plant net nitrogen uptake (content) increased significantly in all successful inoculation treatments and co-inoculated treatment when compared with control. These results hold promise for incorporation of inoculation of Populus sp. with appropriate mycorrhizal fungi and selected bacteria into commercial nursery system to improve the establishment of Populus in various sites. (author)

  11. Plant-by-plant variations of bacterial communities associated with leaves of the nickel hyperaccumulator Alyssum bertolonii Desv.

    Science.gov (United States)

    Mengoni, Alessio; Pini, Francesco; Huang, Li-Nan; Shu, Wen-Sheng; Bazzicalupo, Marco

    2009-10-01

    Bacteria associated with tissues of metal-hyperaccumulating plants are of great interest due to the multiple roles they may play with respect to plant growth and resistance to heavy metals. The variability of bacterial communities associated with plant tissues of three populations of Alyssum bertolonii, a Ni hyperaccumulator endemic of serpentine outcrops of Central Italy, was investigated. Terminal-restriction fragment length polymorphism (T-RFLP) analysis of bacterial 16S rRNA genes was applied to DNA extracted from leaf tissues of 30 individual plants from three geographically separated serpentine outcrops. Moreover, T-RFLP fingerprinting was also performed on DNA extracted from the same soils from which the plants were collected. Fifty-nine unique terminal-restriction fragments (TRFs) were identified, with more than half of the taxonomically interpreted TRFs assigned to Alpha- and Gamma-Proteobacteria and Clostridia. Data were then used to define the extent of variation of bacterial communities due to single plants or to plant populations. Results indicated a very high plant-by-plant variation of leaf-associated community (more than 93% of total variance observed). However, a core (numerically small) of plant-specific TRFs was found. This work demonstrates that plant-associated bacterial communities represent a large reservoir of biodiversity and that the high variability existing between plants, even from the same population, should be taken into account in future studies on association between bacteria and metal-hyperaccumulating plants. PMID:19479304

  12. Amazonian dark Earth and plant species from the Amazon region contribute to shape rhizosphere bacterial communities.

    Science.gov (United States)

    Barbosa Lima, Amanda; Cannavan, Fabiana Souza; Navarrete, Acacio Aparecido; Teixeira, Wenceslau Geraldes; Kuramae, Eiko Eurya; Tsai, Siu Mui

    2015-05-01

    Amazonian Dark Earths (ADE) or Terra Preta de Índio formed in the past by pre-Columbian populations are highly sustained fertile soils supported by microbial communities that differ from those extant in adjacent soils. These soils are found in the Amazon region and are considered as a model soil when compared to the surrounding and background soils. The aim of this study was to assess the effects of ADE and its surrounding soil on the rhizosphere bacterial communities of two leguminous plant species that frequently occur in the Amazon region in forest sites (Mimosa debilis) and open areas (Senna alata). Bacterial community structure was evaluated using terminal restriction fragment length polymorphism (T-RFLP) and bacterial community composition by V4 16S rRNA gene region pyrosequencing. T-RFLP analysis showed effect of soil types and plant species on rhizosphere bacterial community structure. Differential abundance of bacterial phyla, such as Acidobacteria, Actinobacteria, Verrucomicrobia, and Firmicutes, revealed that soil type contributes to shape the bacterial communities. Furthermore, bacterial phyla such as Firmicutes and Nitrospira were mostly influenced by plant species. Plant roots influenced several soil chemical properties, especially when plants were grown in ADE. These results showed that differences observed in rhizosphere bacterial community structure and composition can be influenced by plant species and soil fertility due to variation in soil attributes. PMID:25103911

  13. Comparison of Bacterial Community Structures in the Rhizoplane of Tomato Plants Grown in Soils Suppressive and Conducive towards Bacterial Wilt

    OpenAIRE

    Shiomi, Yoshitaka; Nishiyama, Masaya; Onizuka, Tomoko; Marumoto, Takuya

    1999-01-01

    It has been reported that the growth of Ralstonia solanacearum is suppressed at the rhizoplane of tomato plants and that tomato bacterial wilt is suppressed in plants grown in a soil (Mutsumi) in Japan. To evaluate the biological factors contributing to the suppressiveness of the soil in three treated Mutsumi soils (chloroform fumigated soil; autoclaved soil mixed with intact Mutsumi soil; and autoclaved soil mixed with intact, wilt-conducive Yamadai soil) infested with R. solanacearum, we bi...

  14. 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

    Directory of Open Access Journals (Sweden)

    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.

  15. Effect of Inoculation of Acacia senegal mature trees with Mycorrhiza and Rhizobia on soil properties and microbial community structure

    Science.gov (United States)

    Assigbetsé, K.; Ciss, I.; Bakhoum, N.; Dieng, L.

    2012-04-01

    Inoculation of legume plants with symbiotic microorganisms is widely used to improve their development and productivity. The objective of this study was to investigate the effect of inoculation of Acacia senegal mature trees with rhizobium (Sinorhizobium) and arbuscular mycorrhizal fungus (G. mosseae, G. fasciculatum, G. intraradices) either singly or in combination, on soil properties, activity and the genetic structure of soil microbial communities. The experiment set up in Southern Senegal consisted of 4 randomized blocks of A. senegal mature trees with 4 treatments including inoculated trees with Rhizobium (R), mycorrhizal fungus (M) and with Rhizobium+mycorhizal fungus (RM) and non-inoculated control (CON). Soil were sampled 2 years after the inoculation. Soil pH, C and N and available P contents were measured. The microbial abundance and activity were measured in terms of microbial biomass C (MBC) and basal soil respiration. The community structure of the total bacterial, diazotrophic and denitrifying communities was assessed by denaturing gradient gel electrophoresis of 16S rDNA, nifH and nirK genes respectively. Inoculations with symbiont under field conditions have increased soil pH. The C and N contents were enhanced in the dual-inoculated treatments (RM). The mycorrhized treatment have displayed the lowest available P contents while RM and R treatments exhibited higher contents rates. The microbial biomass C rates were higher in treatments co-inoculated with AM fungi and Rhizobium than in those inoculated singly with AM fungi or Rhizobium strains. The basal soil respiration were positively correlated to MBC, and the highest rates were found in the co-inoculated treatments. Fingerprints of 16S rDNA gene exhibited similar patterns between inoculated treatments and the control showing that the inoculation of mature trees have not impacted the total bacterial community structure. In contrast, the inoculated treatments have displayed individually different

  16. Bacterial communities of two parthenogenetic aphid species cocolonizing two host plants across the Hawaiian Islands.

    Science.gov (United States)

    Jones, Ryan T; Bressan, Alberto; Greenwell, April M; Fierer, Noah

    2011-12-01

    Aphids (Hemiptera: Aphididae) have been the focus of several studies with respect to their interactions with inherited symbionts, but bacterial communities of most aphid species are still poorly characterized. In this research, we used bar-coded pyrosequencing to characterize bacterial communities in aphids. Specifically, we examined the diversity of bacteria in two obligately parthenogenetic aphid species (the melon aphid, Aphis gossypii, and the cardamom aphid, Pentalonia caladii) cocolonizing two plant species (taro, Colocasia esculenta, and ginger, Alpinia purpurata) across four Hawaiian Islands (Hawaii, Kauai, Maui, and Oahu). Results from this study revealed that heritable symbionts dominated the bacterial communities for both aphid species. The bacterial communities differed significantly between the two species, and A. gossypii harbored a more diverse bacterial community than P. caladii. The bacterial communities also differed across aphid populations sampled from the different islands; however, communities did not differ between aphids collected from the two host plants. PMID:21965398

  17. The dynamics of apoplast phenolics in tobacco leaves following inoculation with bacteria

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    Con Jacyn Baker

    2015-08-01

    Full Text Available This study demonstrates that the accumulation of apoplastic phenolics is stimulated in planta in response to bacterial inoculation. Past studies have shown that levels of extracellular phenolics are elicited in plant cell suspensions in response to bacteria, and that tomato plants infected with viroids showed changes in apoplastic phenolics. The method described here monitored changes in apoplastic phenolics in tobacco leaves following bacterial inoculation of the same tissue. Inoculation with a saprophyte, Pseudomonas fluorescens, which does not cause visible symptoms or physical damage, was used to elicit phenolics and examine the effects of variable parameters on phenolic composition. Location of the inoculation on the leaf, position or developmental age of the leaf on the plant, and inoculum concentration were standardized for further experiments. The patterns of phenolic change in the apoplast were compared for tobacco inoculated with P. syringae pathovars, pv. syringae, which causes a resistant HR reaction within 15 h, and pv. tabaci, which causes a susceptible reaction with delayed visible symptoms. Both pathogens elicited lower increased levels of acetosyringone compared to the saprophyte, P. fluorescens but had greatly increased levels of the chlorogenic acid derivatives. The latter metabolites appear to have come from the intracellular stores, which could

  18. The dynamics of apoplast phenolics in tobacco leaves following inoculation with bacteria.

    Science.gov (United States)

    Baker, Con J; Mock, Norton M; Smith, Jodi M; Aver'yanov, Andrey A

    2015-01-01

    This study demonstrates that the accumulation of apoplastic phenolics is stimulated in planta in response to bacterial inoculation. Past studies have shown that levels of extracellular phenolics are elicited in plant cell suspensions in response to bacteria, and that tomato plants infected with viroids showed changes in apoplastic phenolics. The method described here monitored changes in apoplastic phenolics in tobacco leaves following bacterial inoculation of the same tissue. Inoculation with a saprophyte, Pseudomonas fluorescens, which does not cause visible symptoms or physical damage, was used to elicit phenolics and examine the effects of variable parameters on phenolic composition. Location of the inoculation on the leaf, position, or developmental age of the leaf on the plant, and inoculum concentration were standardized for further experiments. The patterns of phenolic change in the apoplast were compared for tobacco inoculated with P. syringae pathovars, pv. syringae, which causes a resistant HR reaction within 15 h, and pv. tabaci, which causes a susceptible reaction with delayed visible symptoms. Both pathogens elicited lower increased levels of acetosyringone compared to the saprophyte, P. fluorescens but had greatly increased levels of the chlorogenic acid derivatives. The latter metabolites appear to have come from the intracellular stores, which could indicate a weakening of the apoplast/symplast barrier. This unexpected aspect will require further study of intracellular phenolics. PMID:26347765

  19. Inoculation of tomato plants with rhizobacteria enhances the performance of the phloem-feeding insect Bemisia tabaci

    OpenAIRE

    Shavit, Roee; Ofek-Lalzar, Maya; Burdman, Saul; Morin, Shai

    2013-01-01

    In their natural environment, plants experience multiple biotic interactions and respond to this complexity in an integrated manner. Therefore, plant responses to herbivory are flexible and depend on the context and complexity in which they occur. For example, plant growth promoting rhizobacteria (PGPR) can enhance plant growth and induce resistance against microbial pathogens and herbivorous insects by a phenomenon termed induced systemic resistance (ISR). In the present study, we investigat...

  20. Inoculação de suspensão bacteriana de Plesiomonas shigelloides em Jundiá, Rhamdia quelen (Teleostei: Pimelodidae Inoculation of bacterial suspension of Plesiomonas shigelloides in jundiá, Rhamdia quelen (Teleostei: Pimelodidae

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    Cheila de Lima Boijink

    2001-06-01

    Full Text Available Com o crescimento da aqüicultura mundial e intensificação da criação de peixes, os animais ficam sujeitos às enfermidades bacterianas e outras. Com o objetivo de avaliar a patogenicidade da Plesiomonas shigelloides para jundiás (Rhamdia quelen, diferentes concentrações bacterianas (3 x 10(8 e 9 x 10(8 UFC - Unidade Formadora de Colônia/ml foram inoculadas por via intraperitoneal. Foram utilizados 84 jundiás juvenis com peso e comprimento médios de 24,37 ± 4,28g e 14,42 ± 1,62cm, respectivamente. Os animais inoculados foram mantidos durante 21 dias, em caixas d'agua de amianto, em condições semelhantes de temperatura, pH, alcalinidade e dureza. Os jundiás foram sacrificados a cada dois dias para contagem de UFC/ml de tecido renal. Por observações diárias, constatou-se que a inoculação intraperitoneal de Plesiomonas shigelloides não ocasionou nenhuma alteração nos jundiás, independente da concentração inoculada. As contagens das bactérias nos rins dos jundiás mantiveram-se entre 10(5 e 10(6UFC/ml até o 21º dia, quando o experimento foi finalizado.As worldwide aquaculture has grown, and intensification in fish raising, the animals are subject to bacterial diseases and others. With the aim of evaluating pathogenicity of Plesiomonas shigelloides for "jundiá" (Rhamdia quelen, different bacterial concentrations (3 x 10(8 e 9 x 10(8 CFU - Colony Former Unit/ml were inoculated via peritoneum. Eigthy four juvenile "jundiá" averaging 24.37 ± 4,28g of weight and 14.42 ± 1,62cm of length were utilized. The inoculated animals were maintained for 21 days, in asbestos water tanks, at similar temperature, pH, alkalinity and hardness conditions. The "jundiás" were slaughtered every other day for counting UFC/ml renal tissue. For daily inspections, it was observed that intraperitoneal inoculation of Plesiomonas shigelloides did not cause any change in the catfishes, regardless inoculated concentration. Bacteria counting in

  1. Inoculation of drought-stressed strawberry with a mixed inoculum of two arbuscular mycorrhizal fungi: effects on population dynamics of fungal species in roots and consequential plant tolerance to water deficiency.

    Science.gov (United States)

    Boyer, Louisa Robinson; Brain, Philip; Xu, Xiang-Ming; Jeffries, Peter

    2015-04-01

    The effect of inoculation with two arbuscular mycorrhizal fungi (AMF) on growth and drought tolerance of cultivated strawberry (Fragaria × ananassa) was studied. Three treatments (a single treatment either of Funneliformis mosseae BEG25, Funneliformis geosporus BEG11 or a 50:50 mixed inoculation treatment of both species) were compared to uninoculated plants. Species-specific primers for qPCR quantification of F. geosporus and F. mosseae DNA were developed to quantify the relative abundance of each fungus in roots of strawberry under different conditions of water stress. Co-occupation of the same root by both species was shown to commonly occur, but their relative abundance varied with water stress (reduced irrigation of up to 40%). Greater root colonisation was observed microscopically under water stress, but this increased colonisation was often accompanied with decreased amounts of fungal DNA in the root. F. mosseae tended to become more abundant under water stress relative to F. geosporus. There was significant correlation in the fungal colonisation measurements from the microscopic and qPCR methods under some conditions, but the nature of this relationship varied greatly with AMF inoculum and abiotic conditions. Single-species inoculation treatments gave similar benefits to the host to the mixed inoculation treatment regardless of irrigation regime; here, amount of colonisation was of greater importance than functional diversity. The addition of AMF inocula to plants subjected to reduced irrigation restored plant growth to the same or higher values as the non-mycorrhizal, fully-watered plants. The water use efficiency of plants was greater under the regulated deficit irrigation (RDI) regime and in AMF-inoculated plants, but there were no significant differences between plants inoculated with the single or combined inoculum. This study demonstrated that the increase in plant growth was directly influenced by an increase in root colonisation by AMF when

  2. The effects of bacterial volatile emissions on plant abiotic stress tolerance

    OpenAIRE

    Xiao-min LIU; Zhang, Huiming

    2015-01-01

    Plant growth-promoting rhizobacteria (PGPR) are beneficial plant symbionts that have been successfully used in agriculture to increase seedling emergence, plant weight, crop yield, and disease resistance. Some PGPR strains release volatile organic compounds (VOCs) that can directly and/or indirectly mediate increases in plant biomass, disease resistance, and abiotic stress tolerance. This mini-review focuses on the enhancement of plant abiotic stress tolerance by bacterial VOCs. The review co...

  3. Capability of Streptomyces spp. in Controlling Bacterial Leaf Blight Disease in Rice Plants

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    Ratih D. Hastuti

    2012-01-01

    Full Text Available Problem statement: Bacterial Leaf Blight (BLB caused by Xanthomonas oryzae pv. oryzae (Xoo is the most damaging disease in lowland rice growing areas in Indonesia. Streptomyces spp. have been known as a producer of antimicrobial compounds that can be used as biocontrol agents. This study examined the ability of three promising indigenous Streptomyces isolates which were previously selected from in vitro agar media and greenhouse test to suppress natural infection of Xoo during dry and wet season trials in 2009/2010 at the Muara Experimental Research Station, Bogor West Java, Indonesia. Approach: Streptomyces isolates (PS4-16, LBR-02 and LSW-05 were applied through seed coating in a peat-based carrier followed by seedling soaking, spray treatment, or combination of both methods, either singly or in combination of two or three isolates. The number of Streptomyces population in the peat carrier at the time of inoculation was above 107 cell g-1. The efficacy of Streptomyces was compared to that chemical spray using NORDOX 56 WP (a.i., zinc oxide 56% and non-treatment. Treated and untreated seeds were grown in plots (5×5 m2 and set in a randomized complete block design with four replications. Results: In the dry season experiment, application of Streptomyces spp. reduced BLB severity when compared to that of untreated plots, although did not reduce BLB incidence. PS4-16, applied singly through seed coating followed by seedling soaking, reduced the Area Under Disease Progress Curve (AUDPC at 70 Days After Planting (DAP to 1458, which was equally effective to the chemical spray (AUDPC value 1434 and simultaneously promoted plant height and gave the highest rice yield. In the wet season trial PS4-16 and LBR-02, applied singly or in dual combination through seed coating followed by seedling soaking, suppressed BLB severity, PS4-16 was confirmed as the most effective isolate by reducing the AUDPC to 1923, which was not significantly different to the

  4. Plant tolerance to mercury in a contaminated soil is enhanced by the combined effects of humic matter addition and inoculation with arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Cozzolino, V; De Martino, A; Nebbioso, A; Di Meo, V; Salluzzo, A; Piccolo, A

    2016-06-01

    In a greenhouse pot experiment, lettuce plants (Lactuca sativa L.) were grown in a Hg-contaminated sandy soil with and without inoculation with arbuscular mycorrhizal fungi (AMF) (a commercial inoculum containing infective propagules of Rhizophagus irregularis and Funneliformis mosseae) amended with different rates of a humic acid (0, 1, and 2 g kg(-1) of soil), with the objective of verifying the synergistic effects of the two soil treatments on the Hg tolerance of lettuce plants. Our results indicated that the plant biomass was significantly increased by the combined effect of AMF and humic acid treatments. Addition of humic matter to soil boosted the AMF effect on improving the nutritional plant status, enhancing the pigment content in plant leaves, and inhibiting both Hg uptake and Hg translocation from the roots to the shoots. This was attributed not only to the Hg immobilization by stable complexes with HA and with extraradical mycorrhizal mycelium in soil and root surfaces but also to an improved mineral nutrition promoted by AMF. This work indicates that the combined use of AMF and humic acids may become a useful practice in Hg-contaminated soils to reduce Hg toxicity to crops. PMID:26931658

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

    OpenAIRE

    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 provide novel ways for the production of disease resistant plants. This thesis describes the results of two research projects that have been undertaken to investigate the potential of such a novel way, name...

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

    OpenAIRE

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

    2013-01-01

    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 toma...

  7. Ralstonia solanacearum, a widespread bacterial plant pathogen in the post-genomic era

    OpenAIRE

    Peeters, Nemo; Guidot, Alice; Vailleau, Fabienne; Valls i Matheu, Marc

    2013-01-01

    Ralstonia solanacearum is a soil-borne bacterium causing the widespread disease known as bacterial wilt. Ralstonia solanacearum is also the causal agent of Moko disease of banana and brown rot of potato. Since the last R. solanacearum pathogen profile was published 10 years ago, studies concerning this plant pathogen have taken a genomic and post-genomic direction. This was pioneered by the first sequenced and annotated genome for a major plant bacterial pathogen and followed by many more gen...

  8. Bacterial Symbionts of a Devastating Coffee Plant Pest, the Stinkbug Antestiopsis thunbergii (Hemiptera: Pentatomidae)

    OpenAIRE

    Matsuura, Yu; Hosokawa, Takahiro; Serracin, Mario; Tulgetske, Genet M.; Miller, Thomas A.; Fukatsu, Takema

    2014-01-01

    Stinkbugs of the genus Antestiopsis, so-called antestia bugs or variegated coffee bugs, are notorious pests of coffee plants in Africa. We investigated the symbiotic bacteria associated with Antestiopsis thunbergii, a major coffee plant pest in Rwanda. PCR, cloning, sequencing, and phylogenetic analysis of bacterial genes identified four distinct bacterial lineages associated with A. thunbergii: a gammaproteobacterial gut symbiont and symbionts representing the genera Sodalis, Spiroplasma, an...

  9. Trophic network architecture of root-associated bacterial communities determines pathogen invasion and plant health

    OpenAIRE

    Wei, Zhong; Yang, Tianjie; Friman, Ville-Petri; Xu, Yangchun; Shen, Qirong; Jousset, Alexandre

    2015-01-01

    Host-associated bacterial communities can function as an important line of defence against pathogens in animals and plants. Empirical evidence and theoretical predictions suggest that species-rich communities are more resistant to pathogen invasions. Yet, the underlying mechanisms are unclear. Here, we experimentally test how the underlying resource competition networks of resident bacterial communities affect invasion resistance to the plant pathogen Ralstonia solanacearum in microcosms and ...

  10. Mixed sugarcane and elephant grass silages with or without bacterial inoculant Silagens mistas de cana-de-açúcar e capim-elefante com ou sem inoculante bacteriano

    Directory of Open Access Journals (Sweden)

    Jucilene Cavali

    2010-03-01

    Full Text Available The effects of different ratios of sugarcane and elephant grass (0:100, 25:75, 50:50, 75:25 and 100:0% of the natural basis were assessed on the chemical composition and losses in silages treated with a bacterial inoculant, using laboratory silos. A 2 × 5 factorial arrangement (with and without inoculant and five elephant grass ratios in a randomized blocks design with three replications was used. Interaction was observed in the sugarcane and elephant grass ratio × bacterial inoculant for crude protein (CP and pH. The other variables were influenced only by the increasing proportions of elephant grass. The contents of dry matter, neutral detergent fiber corrected for ashes and protein, acid detergent fiber, insoluble protein in acid detergent fiber, hemicellulose and lignin in the silages increased linearly with the proportions of elephant grass. The water soluble carbohydrate contents and dry matter in vitro digestibility of the silages decreased linearly with the increase in the proportion of elephant grass. The mean value of ammonia nitrogen in relation to total N was 7.0% (% of DM. The CP values of the inoculated and non-inoculated silage fitted linear models. The highest CP content was observed in the silage treated with inoculant. The pH values of the silages, with and without inoculant, fitted quadratic and linear models, respectively. The lactic acid, propionic acid and butyric acid contents were not influenced by the elephant grass ratios, while the acetic acid content, for the non-inoculated silages, and ethanol decreased linearly with the increase in elephant grass. The ratio of 25% sugarcane and 75% elephant grass improves the nutritional value and increases the silage DM recovery, because of the lower effluent and gas productions. The homofermentative bacterial inoculant does not affect the sugarcane silage.Avaliou-se o efeito de diferentes relações de cana-de-açúcar e capim-elefante (0:100; 25:75; 50:50; 75:25 e 100:0% na mat

  11. [Effectiveness of symbiotic n2-fixation in leguminous plants, as affected by inoculation with rhizobia, by substrate, n-fertilizing, and 14c-sucrose application (author's transl)].

    Science.gov (United States)

    Merbach, W; Schilling, G

    1980-01-01

    Cultivation experiments (Mitscherlich-vessels, quartz sand, 15N-labelled soil, 15N-fertilizer) showed, that various strains of Rhizobium lupini (white and yellow lupines) and of Rhizobium leguminosarum (field beans and peas) induced a different N2-fixation of the inoculated plants, the most effective Rhizobium strains being 367a, Cz, T3, 271 (Rh. lupini), and Azotogen (Rh, leguminosarum). Yellow lupines and field bean plants were supplied with N2 from the air considerably better than white lupines and peas after inoculation with the most effective Rhizobium strains. Application of mineral N to the white lupines and peas not only substituted the inhibited N2-fixation, but increased N amounts in the plants. White lupines fixed more N2 under soil conditions than in quartz sand. An experiment with steam-sterilized and 15-labelled soil as a comparative substrate showed, that this finding was mainly caused by an additional Rhizobium infection from the soil. Contrary to field beans and yellow lupines which fix N2 up to ripeness, white lupines and peas finished N2-fixation in the time of flowering. Mineral-N applied at that time was an additional source of N for last-named plants and they utilized it for production of higher protein yields. Continual spraying of white lupine plants with 14C-labelled sucrose solution after the time of flowering caused continuance of N2-fixation up to the stage of ripeness. It is assumed that the cause of this effect was the competition of growing seeds and nodules for the photosynthates. The supply of nodules was inadequate without external sucrose application. Mineral N inhibited the sucrose-induced N2-fixation of white lupine nodules and their consumption of photosynthates. Consequently, the applied 14C was transported into seeds to a larger extent. The investigations allow the following conclusion: Effective N2-fixation requires nodules being a powerful sink for assimilates on the basis of a highly efficient photosynthetic system of the

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

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    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.

  13. Enhanced Pb Absorption by Hordeum vulgare L. and Helianthus annuus L. Plants Inoculated with an Arbuscular Mycorrhizal Fungi Consortium.

    Science.gov (United States)

    Arias, Milton Senen Barcos; Peña-Cabriales, Juan José; Alarcón, Alejandro; Maldonado Vega, María

    2015-01-01

    The effect of an arbuscular mycorrhizal fungi (AMF) consortium conformed by (Glomus intraradices, Glomus albidum, Glomus diaphanum, and Glomus claroideum) on plant growth and absorption of Pb, Fe, Na, Ca, and (32)P in barley (Hordeum vulgare L.) and sunflower (Helianthus annuus L.) plants was evaluated. AMF-plants and controls were grown in a substrate amended with powdered Pb slag at proportions of 0, 10, 20, and 30% v/v equivalent to total Pb contents of 117; 5,337; 13,659, and 19,913 mg Pb kg(-1) substrate, respectively. Mycorrhizal root colonization values were 70, 94, 98, and 90%, for barley and 91, 97, 95, and 97%, for sunflower. AMF inoculum had positive repercussions on plant development of both crops. Mycorrhizal barley absorbed more Pb (40.4 mg Pb kg(-1)) shoot dry weight than non-colonized controls (26.5 mg Pb kg(-1)) when treated with a high Pb slag dosage. This increase was higher in roots than shoots (650.0 and 511.5 mg Pb kg(-1) root dry weight, respectively). A similar pattern was found in sunflower. Plants with AMF absorbed equal or lower amounts of Fe, Na and Ca than controls. H. vulgare absorbed more total P (1.0%) than H. annuus (0.9%). The arbuscular mycorrizal consortium enhanced Pb extraction by plants. PMID:25495930

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

    Science.gov (United States)

    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. PMID:26974817

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

    International Nuclear Information System (INIS)

    The effectiveness of the plant growth-promoting rhizobacterium Bacillus pumilus regarding growth promotion and radiocesium (137Cs) uptake was evaluated in four Brassica species grown on different 137Cs 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 137Cs concentration and higher 137Cs transfer from the soil to plants. The Brassica species exhibited different 137Cs uptake abilities in the order Komatsuna > turnip > mustard > radish. TF values of 137Cs ranged from 0.018 to 0.069 for all vegetables. Komatsuna possessed the largest root surface area and root volume, and showed a higher 137Cs concentration in plant tissue and higher 137Cs TF values (0.060) than the other vegetables. Higher 137Cs 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 137Cs concentration in plants. • Komatsuna that had larger root volume showed higher 137Cs TF from soil to plants. • Soil with high SOM and Al-vermiculite caused larger 137Cs transfer to plants

  16. 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.

  17. 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. PMID:26863134

  18. Analysis of bacterial communities and bacterial pathogens in a biogas plant by the combination of ethidium monoazide, PCR and Ion Torrent sequencing

    DEFF Research Database (Denmark)

    Luo, Gang; Angelidaki, Irini

    2014-01-01

    The present study investigated the changes of bacterial community composition including bacterial pathogens along a biogas plant, i.e. from the influent, to the biogas reactor and to the post-digester. The effects of post-digestion temperature and time on the changes of bacterial community...... had a significant effect on the changes of bacterial community composition. The changes of bacterial community composition were also reflected in the changes of relative abundance of bacterial pathogens. The richness and relative abundance of bacterial pathogens were reduced after anaerobic digestion...... in the biogas reactor. It was found in batch experiments that bacterial pathogens showed the highest relative abundance and richness after 30days' post-digestion. Streptococcus bovis was found in all the samples. Our results showed that special attention should be paid to the post-digestion since the...

  19. The effects of bacterial volatile emissions on plant abiotic stress tolerance

    Directory of Open Access Journals (Sweden)

    Xiao-Min eLiu

    2015-09-01

    Full Text Available Plant growth-promoting rhizobacteria (PGPR are beneficial plant symbionts that have been successfully used in agriculture to increase seedling emergence, plant weight, crop yield, and disease resistance. Some PGPR strains release volatile organic compounds (VOCs that can directly and/or indirectly mediate increases in plant biomass, disease resistance, and abiotic stress tolerance. This mini-review focuses on the enhancement of plant abiotic stress tolerance by bacterial VOCs. The review considers how PGPR VOCs induce tolerance to salinity and drought stress and also how they improve sulfur and iron nutrition in plants. The potential complexities in evaluating the effects of PGPR VOCs are also discussed.

  20. Growth Response and Tolerance to Heavy Metals of two Swamp Species inoculated with a Plant Growth-Promoting Rhizobacteria

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Dorantes, A.; Labra-Cardon, D.; Guerrero-Zuniga, A.; Montes-Villafan, S.

    2009-07-01

    Due to the sensitivity and the sequestration ability of the microbial communities to heavy metals, microbes have been used for bioremediation. Recently the application of plant growth-promoting rhizobacteria (PGPR) for the bioremediation of this kind of contaminants has been done. This study evaluated the growth response and the tolerance to heavy metals of two swamp species. (Author)

  1. Can mycorrhizal inoculation stimulate the growth and flowering of peat-grown ornamental plants under standard or reduced watering?

    Czech Academy of Sciences Publication Activity Database

    Püschel, David; Rydlová, Jana; Vosátka, Miroslav

    2014-01-01

    Roč. 80, Aug 2014 (2014), s. 93-99. ISSN 0929-1393 R&D Projects: GA MŠk 1M0571 Institutional support: RVO:67985939 Keywords : ornamental plants * arbuscular mycorrhizal fungi * beat-based substrate Subject RIV: EF - Botanics Impact factor: 2.644, year: 2014

  2. Growth Response and Tolerance to Heavy Metals of two Swamp Species inoculated with a Plant Growth-Promoting Rhizobacteria

    International Nuclear Information System (INIS)

    Due to the sensitivity and the sequestration ability of the microbial communities to heavy metals, microbes have been used for bioremediation. Recently the application of plant growth-promoting rhizobacteria (PGPR) for the bioremediation of this kind of contaminants has been done. This study evaluated the growth response and the tolerance to heavy metals of two swamp species. (Author)

  3. Monensin inhibits growth of bacterial contaminants from fuel ethanol plants

    Science.gov (United States)

    Contamination of commercial fermentation cultures by lactic acid bacteria (LAB) is a common and costly problem to the fuel ethanol industry. Virginiamycin (VIR) and penicillin (PEN) are frequently used to control bacterial contamination but extensive use of antibiotics may select for strains with d...

  4. Experimental infection of plants with an herbivore-associated bacterial endosymbiont influences herbivore host selection behavior.

    Directory of Open Access Journals (Sweden)

    Thomas Seth Davis

    Full Text Available Although bacterial endosymbioses are common among phloeophagous herbivores, little is known regarding the effects of symbionts on herbivore host selection and population dynamics. We tested the hypothesis that plant selection and reproductive performance by a phloem-feeding herbivore (potato psyllid, Bactericera cockerelli is mediated by infection of plants with a bacterial endosymbiont. We controlled for the effects of herbivory and endosymbiont infection by exposing potato plants (Solanum tuberosum to psyllids infected with "Candidatus Liberibacter solanacearum" or to uninfected psyllids. We used these treatments as a basis to experimentally test plant volatile emissions, herbivore settling and oviposition preferences, and herbivore population growth. Three important findings emerged: (1 plant volatile profiles differed with respect to both herbivory and herbivory plus endosymbiont infection when compared to undamaged control plants; (2 herbivores initially settled on plants exposed to endosymbiont-infected psyllids but later defected and oviposited primarily on plants exposed only to uninfected psyllids; and (3 plant infection status had little effect on herbivore reproduction, though plant flowering was associated with a 39% reduction in herbivore density on average. Our experiments support the hypothesis that plant infection with endosymbionts alters plant volatile profiles, and infected plants initially recruited herbivores but later repelled them. Also, our findings suggest that the endosymbiont may not place negative selection pressure on its host herbivore in this system, but plant flowering phenology appears correlated with psyllid population performance.

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

    Science.gov (United States)

    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. PMID:23812968

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

    OpenAIRE

    Salwani S.; Amir, H. G.; Najimudin, N.

    2012-01-01

    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 ...

  7. 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. PMID:27252685

  8. Getting to PTI of bacterial RNAs: Triggering plant innate immunity by extracellular RNAs from bacteria.

    Science.gov (United States)

    Park, Yong-Soon; Lee, Boyoung; Ryu, Choong-Min

    2016-07-01

    Defense against diverse biotic and abiotic stresses requires the plant to distinguish between self and non-self signaling molecules. Pathogen/microbe-associated molecular patterns (PAMPs/MAMPs) are pivotal for triggering innate immunity in plants. Unlike in animals and humans, the precise roles of nucleic acids in plant innate immunity are unclear. We therefore investigated the effects of infiltration of total Pseudomonas syringae pv. tomato DC3000 (Pto DC3000) RNAs into Arabidopsis plants. The pathogen population was 10-fold lower in bacterial RNAs pre-treated Arabidopsis plants than in the control. Bacterial RNAs purity was confirmed by physical (sonication) and chemical (RNase A and proteinase K digestion) methods. The perception of bacterial RNAs, especially rRNAs, positively regulated mitogen-activated protein kinase (MAPK) and induced a reactive oxygen species burst, callose deposition, salicylic acid (SA) and jasmonic acid (JA) signaling, and defense-related genes. Therefore, bacterial RNAs function as a new MAMP that activates plant innate immunity, providing a new paradigm for plant-microbe interactions. PMID:27301792

  9. 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.

  10. 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. PMID:27252685

  11. Infection of an Insect Vector with a Bacterial Plant Pathogen Increases Its Propensity for Dispersal

    OpenAIRE

    Martini, Xavier; Hoffmann, Mark; Coy, Monique R; Lukasz L Stelinski; Pelz-Stelinski, Kirsten S.

    2015-01-01

    The spread of vector-transmitted pathogens relies on complex interactions between host, vector and pathogen. In sessile plant pathosystems, the spread of a pathogen highly depends on the movement and mobility of the vector. However, questions remain as to whether and how pathogen-induced vector manipulations may affect the spread of a plant pathogen. Here we report for the first time that infection with a bacterial plant pathogen increases the probability of vector dispersal, and that such mo...

  12. Colonização radicular de plantas cultivadas por Ralstonia solanacearum biovares 1, 2 e 3 Root colonization of cultivated plants inoculated with Ralstonia solanacearum biovar 1, 2 and 3

    Directory of Open Access Journals (Sweden)

    José Magno Martins Bringel

    2001-09-01

    Full Text Available A murcha bacteriana causada por Ralstonia solanacearum é considerada a principal doença de origem bacteriana no mundo. Centenas de espécies de plantas pertencentes a mais de 50 famílias botânicas têm sido relatadas como hospedeiras. Foi avaliada, em condições de casa de vegetação, a colonização radicular de alface, arroz, cebolinha, ervilha, pepino e soja, por seis isolados de Ralstonia solanacearum (Rs, biovares 1, 2 e 3. Estirpes dos isolados de Rs com resistência múltipla aos antibióticos estreptomicina, rifampicina e cloranfenicol foram utilizadas. A colonização foi avaliada 45 dias após a inoculação, através do plaqueamento de suspensão de trituração em meio de cultura semi-seletivo. A ervilha comportou-se como hospedeira de todos os isolados mas, apenas um isolado da biovar 3 foi patogênico a esta espécie. A soja apresentou populações elevadas de quatro isolados distribuídos entre as três biovares e o pepino, de apenas dois isolados das biovares 1 e 3. Exceto para o isolado que foi patogênico à ervilha, as plantas não apresentaram sintomas da doença, comportando-se como hospedeiras não suscetível. O arroz apresentou populações muito baixas de todos os isolados. Alface e cebolinha não hospedaram nenhum dos isolados inoculados. Os resultados mostram a capacidade de Rs colonizar e sobreviver em diferentes espécies de plantas como rizobactérias.Bacterial wilt caused by Ralstonia solanacearum is considered the main plant disease of bacterial origin in the world, where hundreds of plant species in more than 50 botanical families are host plants. Root colonization of lettuce (Lactuca sativa, rice (Oryza sativa, spring onion (Allium fistulosum, pea (Pisum sativum, cucumber (Cucumis sativus, and soybean (Glycine max by six isolates of Ralstonia solanacearum (Rs biovars 1, 2 and 3 was evaluated under greenhouse conditions. Bacterial strains resistant to streptomycin, rifampicin and chloranfenicol were used

  13. 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

  14. A bacterial tyrosine phosphatase inhibits plant pattern recognition receptor activation

    Science.gov (United States)

    Perception of pathogen-associated molecular patterns (PAMPs) by surface-localised pattern-recognition receptors (PRRs) is a key component of plant innate immunity. Most known plant PRRs are receptor kinases and initiation of PAMP-triggered immunity (PTI) signalling requires phosphorylation of the PR...

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

    OpenAIRE

    De La Torre-Ruiz, Neyser; Ruiz-Valdiviezo, Víctor Manuel; Rincón-Molina, Clara Ivette; Rodríguez-Mendiola, Martha; Arias-Castro, Carlos; Gutiérrez-Miceli, Federico Antonio; Palomeque-Dominguez, Héctor; Rincón-Rosales, Reiner

    2016-01-01

    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 sh...

  16. Inoculation of maize with Azospirillum brasilense in the seed furrow

    Directory of Open Access Journals (Sweden)

    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.

  17. Changes in soil bacterial communities induced by the invasive plant Pennisetum setaceum in a semiarid environment

    Science.gov (United States)

    Rodriguez-Caballero, Gema; Caravaca, Fuensanta; del Mar Alguacil, María; Fernández-López, Manuel; José Fernández-González, Antonio; García-Orenes, Fuensanta; Roldán, Antonio

    2016-04-01

    Invasive alien species are considered as a global threat being among the main causes of biodiversity loss. Plant invasions have been extensively studied from different disciplines with the purpose of identifying predictor traits of invasiveness and finding solutions. However, less is known about the implication of the rhizosphere microbiota in these processes, even when it is well known the importance of the interaction between plant rhizosphere and microbial communities. The objective of this study was to determine whether native and invasive plants support different bacterial communities in their rhizospheres and whether there are bacterial indicator species that might be contributing to the invasion process of these ecosystems. We carried out a study in five independent locations under Mediterranean semiarid conditions, where the native Hyparrhenia hirta is being displaced by Pennisetum setaceum, an aggressive invasive Poaceae and soil bacterial communities were amplified and 454-pyrosequenced. Changes in the composition and structure of the bacterial communities, owing to the invasive status of the plant, were detected when the richness and alpha-diversity estimators were calculated as well as when we analyzed the PCoA axes scores. The Indicator Species Analysis results showed a higher number of indicators for invaded communities at all studied taxonomic levels. In conclusion, the effect of the invasiveness and its interaction with the soil location has promoted shifts in the rhizosphere bacterial communities which might be facilitating the invader success in these ecosystems.

  18. Water relations in the interaction of foliar bacterial pathogens with plants.

    Science.gov (United States)

    Beattie, Gwyn A

    2011-01-01

    This review examines the many ways in which water influences the relations between foliar bacterial pathogens and plants. As a limited resource in aerial plant tissues, water is subject to manipulation by both plants and pathogens. A model is emerging that suggests that plants actively promote localized desiccation at the infection site and thus restrict pathogen growth as one component of defense. Similarly, many foliar pathogens manipulate water relations as one component of pathogenesis. Nonvascular pathogens do this using effectors and other molecules to alter hormonal responses and enhance intercellular watersoaking, whereas vascular pathogens use many mechanisms to cause wilt. Because of water limitations on phyllosphere surfaces, bacterial colonists, including pathogens, benefit from the protective effects of cellular aggregation, synthesis of hygroscopic polymers, and uptake and production of osmoprotective compounds. Moreover, these bacteria employ tactics for scavenging and distributing water to overcome water-driven barriers to nutrient acquisition, movement, and signal exchange on plant surfaces. PMID:21438680

  19. Inducible viral inoculation system with cultured plant cells facilitates a biochemical approach for virus-induced RNA silencing.

    Science.gov (United States)

    Tamai, Atsushi; Dohi, Koji; Mori, Masasi; Meshi, Tetsuo; Ishikawa, Masayuki

    2010-03-01

    An inducible virus infection system was demonstrated to be an efficient protein expression system for inducing synchronous virus vector multiplication in suspension-cultured plant cells. A GFP-tagged tomato mosaic virus (ToMV-GFP) derivative that has a defect in its 130 K protein, a silencing suppressor of ToMV, was synchronously infected to tobacco BY2 cultured cells using this system. In the infection-induced cells, viral RNA was degraded rapidly, and a cytosol extract prepared from the infected cells showed RNA degradation activity specific for ToMV- or GFP-related sequences. In lysate prepared from cells infected by ToMV-GFP carrying the wild-type 130 K protein, sequence-specific RNA degradation activity was suppressed, although siRNA derived from the virus was generated. Furthermore, the 130 K protein interfered with 3'-end methylation of siRNA. The inducible virus infection system may provide a method for biochemical analysis of antiviral RNA silencing and silencing suppression by ToMV. PMID:20035436

  20. Recombinant plants provide a new approach to the production of bacterial polysaccharide for vaccines.

    Directory of Open Access Journals (Sweden)

    Claire M Smith

    Full Text Available 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.

  1. Detection of Peroxynitrite in Plants Exposed to Bacterial Infection.

    Science.gov (United States)

    Bellin, Diana; Delledonne, Massimo; Vandelle, Elodie

    2016-01-01

    Peroxynitrite is a highly reactive derivative of nitric oxide (NO) which is gaining attention in the plant biology community because it may play a role in NO signaling during biotic stress. Peroxynitrite can react with many different biomolecules, but its ability to nitrate the tyrosine residues of proteins is particularly important because this may regulate defense signaling in response to pathogens. The analysis of peroxynitrite levels in the context of its proposed defense role requires an accurate and specific detection method. Here, we describe a photometric assay using the fluorescent dye Hong Kong Green 2 as a specific and quantitative probe for peroxynitrite in Arabidopsis thaliana plants challenged with an avirulent strain of Pseudomonas syringae pv. tomato. This protocol includes the preparation of plant samples, the assay procedure, the measurement of peroxynitrite-specific fluorescence, and data presentation. PMID:27094421

  2. Bacterial diversity and composition in the fluid of pitcher plants of the genus Nepenthes.

    Science.gov (United States)

    Takeuchi, Yayoi; Chaffron, Samuel; Salcher, Michaela M; Shimizu-Inatsugi, Rie; Kobayashi, Masaki J; Diway, Bibian; von Mering, Christian; Pernthaler, Jakob; Shimizu, Kentaro K

    2015-07-01

    Pitchers are modified leaves used by carnivorous plants for trapping prey. Their fluids contain digestive enzymes from the plant and they harbor abundant microbes. In this study, the diversity of bacterial communities was assessed in Nepenthes pitcher fluids and the composition of the bacterial community was compared to that in other environments, including the phyllosphere of Arabidopsis, animal guts and another pitcher plant, Sarracenia. Diversity was measured by 454 pyrosequencing of 16S rRNA gene amplicons. A total of 232,823 sequences were obtained after chimera and singleton removal that clustered into 3260 distinct operational taxonomic units (OTUs) (3% dissimilarity), which were taxonomically distributed over 17 phyla, 25 classes, 45 orders, 100 families, and 195 genera. Pyrosequencing and fluorescence in situ hybridization yielded similar estimates of community composition. Most pitchers contained high proportions of unique OTUs, and only 22 OTUs (<0.6%) were shared by ≥14/16 samples, suggesting a unique bacterial assemblage in each pitcher at the OTU level. Diversity analysis at the class level revealed that the bacterial communities of both opened and unopened pitchers were most similar to that of Sarracenia and to that in the phyllosphere. Therefore, the bacterial community in pitchers may be formed by environmental filtering and/or by phyllosphere bacteria. PMID:26138047

  3. Dynamic bacterial communities on reverse-osmosis membranes in a full-scale desalination plant.

    Science.gov (United States)

    Manes, C-L de O; West, N; Rapenne, S; Lebaron, P

    2011-01-01

    To better understand biofouling of seawater reverse osmosis (SWRO) membranes, bacterial diversity was characterized in the intake water, in subsequently pretreated water and on SWRO membranes from a full-scale desalination plant (FSDP) during a 9 month period. 16S rRNA gene fingerprinting and sequencing revealed that bacterial communities in the water samples and on the SWRO membranes were very different. For the different sampling dates, the bacterial diversity of the active and the total bacterial fractions of the water samples remained relatively stable over the sampling period whereas the bacterial community structure on the four SWRO membrane samples was significantly different. The richness and evenness of the SWRO membrane bacterial communities increased with usage time with an increase in the Shannon diversity index of 2.2 to 3.7. In the oldest SWRO membrane (330 days), no single operational taxonomic unit (OTU) dominated and the majority of the OTUs fell into the Alphaproteobacteria or the Planctomycetes. In striking contrast, a Betaproteobacteria OTU affiliated to the genus Ideonella was dominant and exclusively found in the membrane used for the shortest time (10 days). This suggests that bacteria belonging to this genus could be one of the primary colonizers of the SWRO membrane. Knowledge of the dominant bacterial species on SWRO membranes and their dynamics should help guide culture studies for physiological characterization of biofilm forming species. PMID:21108068

  4. A bacterial acetyltransferase destroys plant microtubule networks and blocks secretion

    Science.gov (United States)

    The eukaryotic cytoskeleton is essential for structural support and intracellular transport, and is therefore a common target of animal pathogens. However, no phytopathogenic effector has yet been demonstrated to specifically target the plant cytoskeleton. Here we show that the Pseudomonas syringae...

  5. Bacterial lipopolysaccharides in plant and mammalian innate immunity.

    Science.gov (United States)

    De Castro, Cristina; Holst, Otto; Lanzetta, Rosa; Parrilli, Michelangelo; Molinaro, Antonio

    2012-10-01

    This mini-review gives a structural view on the lipopolysaccharides (LPSs), the endotoxin from Gram negative bacteria, paying attention on the features that are relevant for their activity as elicitors of the innate immune system of humans, animals and plants. PMID:22533617

  6. Biological Inoculants in Forage Conservation

    Directory of Open Access Journals (Sweden)

    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.

  7. Response of leaf endophytic bacterial community to elevated CO2 at different growth stages of rice plant

    OpenAIRE

    Ren, Gaidi; Zhang, Huayong; Lin, Xiangui; Zhu, Jianguo; Jia, Zhongjun

    2015-01-01

    Plant endophytic bacteria play an important role in plant growth and health. In the context of climate change, the response of plant endophytic bacterial communities to elevated CO2 at different rice growing stages is poorly understood. Using 454 pyrosequencing, we investigated the response of leaf endophytic bacterial communities to elevated CO2 (eCO2) at the tillering, filling, and maturity stages of the rice plant under different nitrogen fertilization conditions [low nitrogen fertilizatio...

  8. Response of leaf endophytic bacterial community to elevated CO2 at different growth stages of rice plant

    OpenAIRE

    Gaidi eRen; Huayong eZhang; Xiangui eLin; Jianguo eZhu; Zhongjun eJia

    2015-01-01

    Plant endophytic bacteria play an important role in plant growth and health. In the context of climate change, the response of plant endophytic bacterial communities to elevated CO2 at different rice growing stages is poorly understood. Using 454 pyrosequencing, we investigated the response of leaf endophytic bacterial communities to elevated CO2 (eCO2) at the tillering, filling and maturity stages of the rice plant under different nitrogen fertilization conditions (low nitrogen fertilization...

  9. Sturdy fungi : researchers at the University of Saskatchewan say inoculating plants with spores prior to reclamation planting will give them a more efficient future in tailings areas

    Energy Technology Data Exchange (ETDEWEB)

    Bentein, J.

    2010-09-15

    A cost-effective method of reclaiming oil sands mining sites may also hold the potential for growing crops on dry soils without the need for fertilizers or irrigation. The method is currently being researched by a University of Saskatchewan professor who initially noted species that had taken root at an oil sands tailings site. The professor has collected and analyzed dandelions and other plants from areas in the Arctic archipelago to study the characteristics that enable them to live in harsh conditions. The fungi colonizing the roots of plants taken from 3 oil sands tailings sites have been analyzed to determine their role in increasing the survival rates of plants at the disturbed sites. Planting of the primary successors with the appropriate fungi will help to establish an environment where diverse ecological successors can survive. The approach may also be used to grow plants in arid and unusable lands. 2 figs.

  10. Induced release of a plant-defense volatile 'deceptively' attracts insect vectors to plants infected with a bacterial pathogen.

    Directory of Open Access Journals (Sweden)

    Rajinder S Mann

    Full Text Available Transmission of plant pathogens by insect vectors is a complex biological process involving interactions between the plant, insect, and pathogen. Pathogen-induced plant responses can include changes in volatile and nonvolatile secondary metabolites as well as major plant nutrients. Experiments were conducted to understand how a plant pathogenic bacterium, Candidatus Liberibacter asiaticus (Las, affects host preference behavior of its psyllid (Diaphorina citri Kuwayama vector. D. citri were attracted to volatiles from pathogen-infected plants more than to those from non-infected counterparts. Las-infected plants were more attractive to D. citri adults than non-infected plants initially; however after feeding, psyllids subsequently dispersed to non-infected rather than infected plants as their preferred settling point. Experiments with Las-infected and non-infected plants under complete darkness yielded similar results to those recorded under light. The behavior of psyllids in response to infected versus non-infected plants was not influenced by whether or not they were carriers of the pathogen. Quantification of volatile release from non-infected and infected plants supported the hypothesis that odorants mediate psyllid preference. Significantly more methyl salicylate, yet less methyl anthranilate and D-limonene, was released by infected than non-infected plants. Methyl salicylate was attractive to psyllids, while methyl anthranilate did not affect their behavior. Feeding on citrus by D. citri adults also induced release of methyl salicylate, suggesting that it may be a cue revealing location of conspecifics on host plants. Infected plants were characterized by lower levels of nitrogen, phosphorus, sulfur, zinc, and iron, as well as, higher levels of potassium and boron than non-infected plants. Collectively, our results suggest that host selection behavior of D. citri may be modified by bacterial infection of plants, which alters release of

  11. Experimental infection of plants with an herbivore-associated bacterial endosymbiont influences herbivore host selection behavior

    Science.gov (United States)

    Although bacterial endosymbioses are common among phloeophagous herbivores, little is known regarding the effects of symbionts on herbivore host selection and population dynamics. We tested the hypothesis that plant selection and reproductive performance by a phloem-feeding herbivore (potato psyllid...

  12. Plant secondary metabolite-induced shifts in bacterial community structure and degradative ability in contaminated soil

    Czech Academy of Sciences Publication Activity Database

    Uhlík, O.; Musilová, L.; Rídl, Jakub; Hroudová, Miluše; Vlček, Čestmír; Koubek, J.; Holečková, M.; Mackova, M.; Macek, T.

    2013-01-01

    Roč. 97, č. 20 (2013), s. 9245-9256. ISSN 0175-7598 Grant ostatní: EK(XE) 265946; GA MŠk(CZ) ME10041 Institutional support: RVO:68378050 Keywords : plant secondary metabolites (PSM) * bacterial community * metabolic activity * bioremediation * pyrosequencing Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.811, year: 2013

  13. Identification of mVOCs from Andean rhizobacteria and field evaluation of bacterial and mycorrhizal inoculants on growth of potato in its center of origin.

    Science.gov (United States)

    Velivelli, Siva L S; Kromann, Peter; Lojan, Paul; Rojas, Mercy; Franco, Javier; Suarez, Juan Pablo; Prestwich, Barbara Doyle

    2015-04-01

    Food security (a pressing issue for all nations) faces a threat due to population growth, land availability for growing crops, a changing climate (leading to increases in both abiotic and biotic stresses), heightened consumer awareness of the risks related to the use of agrichemicals, and also the reliance on depleting fossil fuel reserves for their production. Legislative changes in Europe mean that fewer agrichemicals will be available in the future for the control of crop pests and pathogens. The need for the implementation of a more sustainable agricultural system globally, incorporating an integrated approach to disease management, has never been more urgent. To that end, the Valorizing Andean Microbial Diversity (VALORAM) project (http://valoram.ucc.ie), funded under FP7, examined the role of microbial communities in crop production and protection to improve the sustainability, food security, environmental protection, and productivity for rural Andean farmers. During this work, microbial volatile organic compounds (mVOCs) of 27 rhizobacterial isolates were identified using gas chromatography/mass spectrometry (GC/MS), and their antifungal activity against Rhizoctonia solani was determined in vitro and compared to the activity of a selection of pure volatile compounds. Five of these isolates, Pseudomonas palleroniana R43631, Bacillus sp. R47065, R47131, Paenibacillus sp. B3a R49541, and Bacillus simplex M3-4 R49538 trialled in the field in their respective countries of origin, i.e., Bolivia, Peru, and Ecuador, showed significant increase in the yield of potato. The strategy followed in the VALORAM project may offer a template for the future isolation and determination of putative biocontrol and plant growth-promoting agents, useful as part of a low-input integrated pest management system. PMID:25339308

  14. Inoculation of Acacia mangium with Alginate Beads Containing Selected Bradyrhizobium Strains under Field Conditions: Long-Term Effect on Plant Growth and Persistence of the Introduced Strains in Soil.

    Science.gov (United States)

    Galiana, A; Prin, Y; Mallet, B; Gnahoua, G M; Poitel, M; Diem, H G

    1994-11-01

    The growth response of Acacia mangium Willd. to inoculation with selected Bradyrhizobium strains was investigated in two field trials in the Ivory Coast (West Africa). In the first trial (Anguededou), four provenances (i.e., trees originating from seeds harvested in different geographical areas) of A. mangium were inoculated with four Bradyrhizobium strains from different origins. Six months after being transplanted in the field, the heights of all inoculated trees showed a statistically significant increase of 9 to 26% compared with those of uninoculated trees, with the most effective strain being Aust 13c. After 19 months, the positive effect of inoculation on tree growth was confirmed. The effect of A. mangium provenance on tree growth was also highly significant. Trees from the Oriomo provenance of Papua New Guinea had a mean height that was 25% greater than those of other provenances. Analysis of variance showed a highly significant effect of interaction between strain and host provenance factors. Thus, most effective strain x provenance combinations could be proposed. Immunological identification of strains clearly showed that 90 to 100% of nodules from trees inoculated with three of the four Bradyrhizobium strains or from uninoculated trees contained exclusively Aust 13c 23 months after tree transplantation. This predominance of Aust 13c in nodules was still observed 42 months after tree transplantation. The second experiment (Port-Bouët), performed with a different soil, confirmed the long-term positive effect of Aust 13c on plant growth, its high competitive ability against indigenous strains, and its persistence in soil. Strain Aust 13c should thus be of great interest for inoculating A. mangium under a wide range of field conditions. PMID:16349430

  15. Virulence Program of a Bacterial Plant Pathogen: The Dickeya Model.

    Science.gov (United States)

    Reverchon, S; Muskhelisvili, G; Nasser, W

    2016-01-01

    The pectinolytic Dickeya spp. are Gram-negative bacteria causing severe disease in a wide range of plant species. Although the Dickeya genus was initially restricted to tropical and subtropical areas, two Dickeya species (D. dianthicola and D. solani) emerged recently in potato cultures in Europe. Soft-rot, the visible symptoms, is caused by plant cell wall degrading enzymes, mainly pectate lyases (Pels) that cleave the pectin polymer. However, an efficient colonization of the host requires many additional elements including early factors (eg, flagella, lipopolysaccharide, and exopolysaccharide) that allow adhesion of the bacteria and intermediate factors involved in adaptation to new growth conditions encountered in the host (eg, oxidative stress, iron starvation, and toxic compounds). To facilitate this adaptation, Dickeya have developed complex regulatory networks ensuring appropriate expression of virulence genes. This review presents recent advances in our understanding of the signals and genetic circuits impacting the expression of virulence determinants. Special attention is paid to integrated control of virulence functions by variations in the superhelical density of chromosomal DNA, and the global and specific regulators, making the regulation of Dickeya virulence an especially attractive model for those interested in relationships between the chromosomal dynamics and gene regulatory networks. PMID:27571692

  16. Anti-enteric bacterial activity of the traditional medicinal plants of Kanyakumari coast, Tamilnadu, India

    Institute of Scientific and Technical Information of China (English)

    Suyambu Rajan; Parameshwaran Suvetha; Thiyagarajan Thirunalasundari; Solomon Jeeva

    2015-01-01

    Objective: To evaluate the antimicrobial potentials of 6 traditionally used medicinal plants to treat gastrointestinal infection against pathogenic bacteria, as most of the pathogens develop drug resistance against commonly used antibiotics. Methods: Crude extracts from different parts of different plants were tested against bacterial strains of clinical significance. Extraction of bioactive principles was done with water and ethanol. Evaluation of antibacterial activity was done by disc diffusion assay against selected bacterial stains. Results: Of the 6 different plant materials tested, extracts prepared from Psidium guajava leaves showed significantly higher efficacy. Extracts prepared using alcohol exhibited higher antibacterial activity when compared to their corresponding aqueous extracts. Conclusions: The findings of the present study suggested that phytochemical extracts of the presently studied plant materials possess significant anti-enteric bacterial activity, and thus lend pharmacological credibility to the suggested traditional use of the plant as a natural remedy for the treatment, management and/or control of gastrointestinal diseases in the coastal tracts of Kanyakumari district, Tamilnadu, India.

  17. Anti-enteric bacterial activity of the traditional medicinal plants of Kanyakumari coast, Tamilnadu, India

    Directory of Open Access Journals (Sweden)

    Suyambu Rajan

    2015-08-01

    Full Text Available Objective: To evaluate the antimicrobial potentials of 6 traditionally used medicinal plants to treat gastrointestinal infection against pathogenic bacteria, as most of the pathogens develop drug resistance against commonly used antibiotics. Methods: Crude extracts from different parts of different plants were tested against bacterial strains of clinical significance. Extraction of bioactive principles was done with water and ethanol. Evaluation of antibacterial activity was done by disc diffusion assay against selected bacterial stains. Results: Of the 6 different plant materials tested, extracts prepared from Psidium guajava leaves showed significantly higher efficacy. Extracts prepared using alcohol exhibited higher antibacterial activity when compared to their corresponding aqueous extracts. Conclusions: The findings of the present study suggested that phytochemical extracts of the presently studied plant materials possess significant anti-enteric bacterial activity, and thus lend pharmacological credibility to the suggested traditional use of the plant as a natural remedy for the treatment, management and/or control of gastrointestinal diseases in the coastal tracts of Kanyakumari district, Tamilnadu, India.

  18. Characterization of culturable bacterial endophytes and their capacity to promote plant growth from plants grown using organic or conventional practices

    Directory of Open Access Journals (Sweden)

    Ye eXia

    2015-07-01

    Full Text Available Plants have a diverse internal microbial biota that has been shown to have an important influence on a range of plant health attributes. Although these endophytes have been found to be widely occurring, few studies have correlated agricultural production practices with endophyte community structure and function. One agricultural system that focuses on preserving and enhancing soil microbial abundance and biodiversity is organic farming, and numerous studies have shown that organically managed system have increased microbial community characteristics. Herein, the diversity and specificity of culturable bacterial endophytes were evaluated in four vegetable crops: corn, tomato, melon and pepper grown under organic or conventional practices. Endophytic bacteria were isolated from surface-sterilized shoot, root and seed tissues and sequence identified. A total of 336 bacterial isolates were identified, and grouped into 32 species and 5 phyla. Among these, 239 isolates were from organically grown plants and 97 from those grown conventionally. Although a diverse range of bacteria were documented, 186 were from the Phylum Firmicutes, representing 55% of all isolates. Using the Shannon diversity index, we observed a gradation of diversity in tissues, with shoots and roots having a similar value, and seeds having the least diversity. Importantly, endophytic microbial species abundance and diversity was significantly higher in the organically grown plants compared to those grown using conventional practices, potentially indicating that organic management practices may increase endophyte presence and diversity. The impact that these endophytes could have on plant growth and yield was evaluated by reintroducing them into tomato plants in a greenhouse environment. Of the bacterial isolates tested, 61% were found to promote tomato plant growth and 50%-64% were shown to enhance biomass accumulation, illustrating their potential agroecosystem application.

  19. Characterization of culturable bacterial endophytes and their capacity to promote plant growth from plants grown using organic or conventional practices.

    Science.gov (United States)

    Xia, Ye; DeBolt, Seth; Dreyer, Jamin; Scott, Delia; Williams, Mark A

    2015-01-01

    Plants have a diverse internal microbial biota that has been shown to have an important influence on a range of plant health attributes. Although these endophytes have been found to be widely occurring, few studies have correlated agricultural production practices with endophyte community structure and function. One agricultural system that focuses on preserving and enhancing soil microbial abundance and biodiversity is organic farming, and numerous studies have shown that organically managed system have increased microbial community characteristics. Herein, the diversity and specificity of culturable bacterial endophytes were evaluated in four vegetable crops: corn, tomato, melon, and pepper grown under organic or conventional practices. Endophytic bacteria were isolated from surface-sterilized shoot, root, and seed tissues and sequence identified. A total of 336 bacterial isolates were identified, and grouped into 32 species and five phyla. Among these, 239 isolates were from organically grown plants and 97 from those grown conventionally. Although a diverse range of bacteria were documented, 186 were from the Phylum Firmicutes, representing 55% of all isolates. Using the Shannon diversity index, we observed a gradation of diversity in tissues, with shoots and roots having a similar value, and seeds having the least diversity. Importantly, endophytic microbial species abundance and diversity was significantly higher in the organically grown plants compared to those grown using conventional practices, potentially indicating that organic management practices may increase endophyte presence and diversity. The impact that these endophytes could have on plant growth and yield was evaluated by reintroducing them into tomato plants in a greenhouse environment. Of the bacterial isolates tested, 61% were found to promote tomato plant growth and 50-64% were shown to enhance biomass accumulation, illustrating their potential agroecosystem application. PMID:26217348

  20. 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

  1. Plant and soil fungal but not soil bacterial communities are linked in long-term fertilized grassland

    Science.gov (United States)

    Cassman, Noriko A.; Leite, Marcio F. A.; Pan, Yao; de Hollander, Mattias; van Veen, Johannes A.; Kuramae, Eiko E.

    2016-03-01

    Inorganic fertilization and mowing alter soil factors with subsequent effects–direct and indirect - on above- and below-ground communities. We explored direct and indirect effects of long-term fertilization (N, P, NPK, Liming) and twice yearly mowing on the plant, bacterial and fungal communities and soil factors. We analyzed co-variation using 16S and 18S rRNA genes surveys, and plant frequency and edaphic factors across treatments. The plant and fungal communities were distinct in the NPK and L treatments, while the bacterial communities and soil factors were distinct in the N and L treatments. Plant community diversity and evenness had low diversity in the NPK and high diversity in the liming treatment, while the diversity and evenness of the bacterial and fungal communities did not differ across treatments, except of higher diversity and evenness in the liming treatment for the bacteria. We found significant co-structures between communities based on plant and fungal comparisons but not between plant and bacterial nor bacterial and fungal comparisons. Our results suggested that the plant and fungal communities are more tightly linked than either community with the bacterial community in fertilized soils. We found co-varying plant, bacterial and fungal taxa in different treatments that may indicate ecological interactions.

  2. Effect of Rhizobium inoculation on some characters of a high protein mutant and its parent field bean Vicia faba L

    International Nuclear Information System (INIS)

    M1011 is a high protein mutant originally selected from the Egyptian bean (Vicia faba L.) variety Giza2 (G2) after seven generations of treating seeds with 4kR of 60Co gamma rays. Both the mutant line M1011 and its parent variety G2 were planted in soil inoculated with Rhizobium phaseoli after being sterilized. The plant and yield characters of both were then investigated. Results showed that the mean values of plant height, total and fertile number of branches per plant, number of pods per plant, seed yield and seed protein content increased significantly in both M1011 and G2 due to pre-sowing Rhizobium inoculation. Significant earliness in flowering and an increase in the number of seeds per pod were also noticed in M1011 after Rhizobium treatment. Therefore, the mutant line showed higher efficiency in utilizing bacterially fixed nitrogen than its parent mother variety Giza2. (author)

  3. Plant nitrogen-use strategy as a driver of rhizosphere archaeal and bacterial ammonia oxidiser abundance.

    Science.gov (United States)

    Thion, Cécile E; Poirel, Jessica D; Cornulier, Thomas; De Vries, Franciska T; Bardgett, Richard D; Prosser, James I

    2016-07-01

    The influence of plants on archaeal (AOA) and bacterial (AOB) ammonia oxidisers (AO) is poorly understood. Higher microbial activity in the rhizosphere, including organic nitrogen (N) mineralisation, may stimulate both groups, while ammonia uptake by plants may favour AOA, considered to prefer lower ammonia concentration. We therefore hypothesised (i) higher AOA and AOB abundances in the rhizosphere than bulk soil and (ii) that AOA are favoured over AOB in the rhizosphere of plants with an exploitative strategy and high N demand, especially (iii) during early growth, when plant N uptake is higher. These hypotheses were tested by growing 20 grassland plants, covering a spectrum of resource-use strategies, and determining AOA and AOB amoA gene abundances, rhizosphere and bulk soil characteristics and plant functional traits. Joint Bayesian mixed models indicated no increase in AO in the rhizosphere, but revealed that AOA were more abundant in the rhizosphere of exploitative plants, mostly grasses, and less abundant under conservative plants. In contrast, AOB abundance in the rhizosphere and bulk soil depended on pH, rather than plant traits. These findings provide a mechanistic basis for plant-ammonia oxidiser interactions and for links between plant functional traits and ammonia oxidiser ecology. PMID:27130939

  4. 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...... 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, in biochar-amended saline soil, strain FD17 performed significantly better than did PsJN in reducing [Na+]xylem. Our results suggested that inoculation of plants with endophytic baterial strains along with biochar amendment could be an effective approach for sustaining crop production in salt...

  5. Development of biological process with pure bacterial cultures for effective bioconversion of sewage treatment plant sludge.

    Science.gov (United States)

    Alam, Zahangir; Muyibi, Suleyman A; Jamal, Parveen

    2007-02-15

    Forty-six bacterial strains were isolated from nine different sources in four treatment plants namely Indah Water Konsortium (IWK) sewage treatment plant (STP), International Islamic University Malaysia (IIUM) wastewater treatment plant-1,-2 and -3 to evaluate the bioconversion process in terms of efficient biodegradation and bioseparation. The bacterial strains isolated were found to be 52.2% (24 isolates) and 47.8% (22 isolates) in the IWK and IIUM treatment plants, respectively. The results showed that higher microbial population (9-10 x 10(4) cfu/mL) was observed in the secondary clarifier of IWK treatment plant. Among the isolates, 23 isolates were gram-positive bacillus (GPB) and gram-positive cocci (GPC), 19 isolates were gram-negative bacillus (GNB) and gram-negative cocci (GNC), and the rest were undetermined. Gram-negative cocci (GNC) were not found in the isolates from IWK. A total of 15 bacterial strains were selected for effective and efficient sludge bioconversion. All the strains were tested against sludge (1% total suspended solids, TSS) to evaluate the biosolids production (TSS% content), chemical oxygen demand (COD) removal and filtration rate (filterability test). The strain S-1 (IWK1001) showed lower TSS content (0.8% TSS), maximum COD removal (84%) and increased filterability (1.1 min/10 mL of filtrate) of treated sludge followed by the strains S-11, S-14, S-2, S-15, S-13, S-7, S-8, S-4, S-3, S-6, S-12, S-16, S-17 and S-9. The pH values in the fermentation broth were affected by the bacterial cultures and recorded as well. Effective bioconversion was observed during the first three days of sludge treatment. PMID:17365300

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

    Science.gov (United States)

    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. PMID:25645593

  7. Infection of an Insect Vector with a Bacterial Plant Pathogen Increases Its Propensity for Dispersal.

    Science.gov (United States)

    Martini, Xavier; Hoffmann, Mark; Coy, Monique R; Stelinski, Lukasz L; Pelz-Stelinski, Kirsten S

    2015-01-01

    The spread of vector-transmitted pathogens relies on complex interactions between host, vector and pathogen. In sessile plant pathosystems, the spread of a pathogen highly depends on the movement and mobility of the vector. However, questions remain as to whether and how pathogen-induced vector manipulations may affect the spread of a plant pathogen. Here we report for the first time that infection with a bacterial plant pathogen increases the probability of vector dispersal, and that such movement of vectors is likely manipulated by a bacterial plant pathogen. We investigated how Candidatus Liberibacter asiaticus (CLas) affects dispersal behavior, flight capacity, and the sexual attraction of its vector, the Asian citrus psyllid (Diaphorina citri Kuwayama). CLas is the putative causal agent of huanglongbing (HLB), which is a disease that threatens the viability of commercial citrus production worldwide. When D. citri developed on CLas-infected plants, short distance dispersal of male D. citri was greater compared to counterparts reared on uninfected plants. Flight by CLas-infected D. citri was initiated earlier and long flight events were more common than by uninfected psyllids, as measured by a flight mill apparatus. Additionally, CLas titers were higher among psyllids that performed long flights than psyllid that performed short flights. Finally, attractiveness of female D. citri that developed on infected plants to male conspecifics increased proportionally with increasing CLas bacterial titers measured within female psyllids. Our study indicates that the phytopathogen, CLas, may manipulate movement and mate selection behavior of their vectors, which is a possible evolved mechanism to promote their own spread. These results have global implications for both current HLB models of disease spread and control strategies. PMID:26083763

  8. Infection of an Insect Vector with a Bacterial Plant Pathogen Increases Its Propensity for Dispersal.

    Directory of Open Access Journals (Sweden)

    Xavier Martini

    Full Text Available The spread of vector-transmitted pathogens relies on complex interactions between host, vector and pathogen. In sessile plant pathosystems, the spread of a pathogen highly depends on the movement and mobility of the vector. However, questions remain as to whether and how pathogen-induced vector manipulations may affect the spread of a plant pathogen. Here we report for the first time that infection with a bacterial plant pathogen increases the probability of vector dispersal, and that such movement of vectors is likely manipulated by a bacterial plant pathogen. We investigated how Candidatus Liberibacter asiaticus (CLas affects dispersal behavior, flight capacity, and the sexual attraction of its vector, the Asian citrus psyllid (Diaphorina citri Kuwayama. CLas is the putative causal agent of huanglongbing (HLB, which is a disease that threatens the viability of commercial citrus production worldwide. When D. citri developed on CLas-infected plants, short distance dispersal of male D. citri was greater compared to counterparts reared on uninfected plants. Flight by CLas-infected D. citri was initiated earlier and long flight events were more common than by uninfected psyllids, as measured by a flight mill apparatus. Additionally, CLas titers were higher among psyllids that performed long flights than psyllid that performed short flights. Finally, attractiveness of female D. citri that developed on infected plants to male conspecifics increased proportionally with increasing CLas bacterial titers measured within female psyllids. Our study indicates that the phytopathogen, CLas, may manipulate movement and mate selection behavior of their vectors, which is a possible evolved mechanism to promote their own spread. These results have global implications for both current HLB models of disease spread and control strategies.

  9. Composição química e estabilidade aeróbia em silagens de milho preparadas com inoculantes bacteriano e/ou enzimático = Chemical composition and aerobic stability of corn silages made with bacterials and/or enzymatic inoculants

    Directory of Open Access Journals (Sweden)

    Agda Luzia de Godoy Gimenes

    2006-04-01

    Full Text Available Este trabalho avaliou o efeito de inoculantes bacterianos e/ou enzimáticos na composição química e na estabilidade aeróbia da silagem de milho confeccionada em minisilos. Os tratamentos foram: SC (silagem controle, SIB (silagem com inoculante bacteriano, SIBE (silagem com inoculante bacteriano e enzimático e SIE (silagem com inoculante enzimático. A adição de inoculante não alterou os teores de matéria orgânica (87,43%, proteína bruta (7,99%, fibra em detergente neutro (55,43% e fibra em detergente ácido (27,67%. Os tratamentos SIE e SC apresentaram, na abertura, o menor (3,28 e maior (3,42 pH, e, após o período de exposição ao ar, o menor (3,87 e maior (6,64 pH, respectivamente. O uso de inoculantes não influenciou os teores de N-amoniacal das silagens. Os tratamentoscom inoculantes apresentaram menor pico de temperatura, maior tempo para atingir o pico de temperatura e maior estabilidade aeróbia.This work evaluated the effect of bacterial and/or enzymatic inoculants on chemical composition and aerobic stability in corn silage, made in mini-silos. The treatments were: CS (control silage, SBI (silage with bacterial inoculant, SBEI (silage with bacterial and enzymatic inoculant and SEI (silage with enzymatic inoculant. The use of inoculants did not affect the organic matter (87,43%, crude protein (7,99%, neutral detergent fiber (55,43% and acid detergent fiber (27,67% contents. The SEI and CS treatments showed the lowest (3,28 and the highest (3,42 pH values in the beginningand after an air exposure period, showed again the lowest (3,87 and the highest (6,64 pH values, respectively. The inoculants used did not affect N-amonniacal contents of the silages. The treatments with inoculants presented the lowest temperature peak, more time to reach this temperature and the highest aerobics stability.

  10. 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. PMID:26759120

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

    Directory of Open Access Journals (Sweden)

    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.

  12. New inoculants on maize silage fermentation

    Directory of Open Access Journals (Sweden)

    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.

  13. The Role of Bacterial Chaperones in the Circulative Transmission of Plant Viruses by Insect Vectors

    Directory of Open Access Journals (Sweden)

    Murad Ghanim

    2013-06-01

    Full Text Available Persistent circulative transmission of plant viruses involves complex interactions between the transmitted virus and its insect vector. Several studies have shown that insect vector proteins are involved in the passage and the transmission of the virus. Interestingly, proteins expressed by bacterial endosymbionts that reside in the insect vector, were also shown to influence the transmission of these viruses. Thus far, the transmission of two plant viruses that belong to different virus genera was shown to be facilitated by a bacterial chaperone protein called GroEL. This protein was shown to be implicated in the transmission of Potato leafroll virus (PLRV by the green peach aphid Myzus persicae, and the transmission of Tomato yellow leaf curl virus (TYLCV by the sweetpotato whitefly Bemisia tabaci. These tri-trophic levels of interactions and their possible evolutionary implications are reviewed.

  14. STUDIES ON NEW FERTILIZATION AND INOCULATION TECHNIQUES FOR PROMOTION OF GROWTH, SEED YIELD AND QUALITY OF SOYBEAN(Glycine max (L.)Merr.)PLANTS

    OpenAIRE

    Tewari, Kaushal; ティワリ, カウサル

    2006-01-01

    Average soybean seed yield in Japan is less than 2t ha-1, although the seed yield is sometimes much higher up to 6t ha-1 in a well managed field under good climatic conditions. Therefore, the present study was carried out in view to obtain better seed yield by employing the deep placement of different feritilizers such as coated urea, lime nitrogen and urea as well as by using different inoculation methods. For this purpose, ten days old seedling with Bradyrhizobium japonicum inoculated paper...

  15. Airborne peptidoglycans as a supporting indicator of bacterial contamination in a metal processing plant

    OpenAIRE

    Marcin Cyprowski; Anna Ławniczek-Wałczyk; Górny, Rafał L.

    2016-01-01

    Objectives: The aim of this study was to assess exposure to airborne endotoxins and peptidoglycans (PGs) as well as possibility of using PGs as a surrogate measure of bacterial exposure in workplaces in a metal processing plant. Material and Methods: Personal dosimetry (N = 11) was used to obtain data on concentrations of viable bacteria, total number of bioaerosol particles, endotoxins and peptidoglycans. To investigate the size distributions of aerosol particles responsible for transport of...

  16. Global Regulation of Virulence Determinants During Plant Colonization in the Bacterial Phytopathogen, Pantoea stewartii subsp. stewartii

    OpenAIRE

    Burbank, Lindsey

    2014-01-01

    Pantoea stewartii subsp. stewartii, the etiological agent of Stewart's wilt, is a bacterial pathogen of sweet corn which colonizes both the apoplast and xylem tissues. During the initial stages of the infection process, the pathogen forms water-soaked lesions through lysis of the plant cells, followed by colonization of the xylem tissue where it can grow to high cell densities and form biofilms. Biofilm formation within the xylem vessels can block water flow, causing the characteristic wiltin...

  17. Parameters That Enhance the Bacterial Expression of Active Plant Polyphenol Oxidases

    OpenAIRE

    Dirks-Hofmeister, Mareike E.; Kolkenbrock, Stephan; Moerschbacher, Bruno. M.

    2013-01-01

    Polyphenol oxidases (PPOs, EC 1.10.3.1) are type-3 copper proteins that enzymatically convert diphenolic compounds into their corresponding quinones. Although there is significant interest in these enzymes because of their role in food deterioration, the lack of a suitable expression system for the production of soluble and active plant PPOs has prevented detailed investigations of their structure and activity. Recently we developed a bacterial expression system that was sufficient for the pr...

  18. Sharing of quorum-sensing signals and role of interspecies communities in a bacterial plant disease

    OpenAIRE

    Hosni, Taha; Moretti, Chiaraluce; Devescovi, Giulia; Suarez-Moreno, Zulma Rocio; Fatmi, M' Barek; Guarnaccia, Corrado; Pongor, Sandor; Onofri, Andrea; Buonaurio, Roberto; Venturi, Vittorio

    2011-01-01

    Pathogenic bacteria interact not only with the host organism but most probably also with the resident microbial flora. In the knot disease of the olive tree (Olea europaea), the causative agent is the bacterium Pseudomonas savastanoi pv. savastanoi (Psv). Two bacterial species, namely Pantoea agglomerans and Erwinia toletana, which are not pathogenic and are olive plant epiphytes and endophytes, have been found very often to be associated with the olive knot. We identified the chemical signal...

  19. Firmicutes dominate the bacterial taxa within sugar-cane processing plants

    OpenAIRE

    Farhana Sharmin; Steve Wakelin; Flavia Huygens; Megan Hargreaves

    2013-01-01

    Sugar cane processing sites are characterised by high sugar/hemicellulose levels, available moisture and warm conditions, and are relatively unexplored unique microbial environments. The PhyloChip microarray was used to investigate bacterial diversity and community composition in three Australian sugar cane processing plants. These ecosystems were highly complex and dominated by four main Phyla, Firmicutes (the most dominant), followed by Proteobacteria, Bacteroidetes, and Chloroflexi. Signif...

  20. BACTERIAL MICROORGANISMS ASSOCIATED WITH THE PLANT TISSUE CULTURE: IDENTIFICATION AND POSSIBLE ROLE (review)

    OpenAIRE

    S.E. DUNAEVA; Yu, S.

    2015-01-01

    Effective sterilization of plant explants and antiseptics rules compliance do not exclude the presence of so-called covert (endophytic) bacteria in in vitro cultures. But the role of these bacteria in tissues cultures has been not enough studied whereas it was related to the explants regeneration capacity and the possibility of animal and human cells transformation under in vitro cultivation. Bacterial strains pathogenic to humans can be stably maintained in cultivated tissues and ex vitro pl...

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

    Directory of Open Access Journals (Sweden)

    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

  2. Early growth promotion and leaf level physiology changes in Burkholderia phytofirmans strain PsJN inoculated switchgrass.

    Science.gov (United States)

    Wang, Bingxue; Mei, Chuansheng; Seiler, John R

    2015-01-01

    Switchgrass (SG) is one of the most promising next generation biofuel crops in North America. Inoculation with bacterial endophytes has improved growth of several plant species. Our study demonstrated that Burkholderia phytofirmans strain PsJN, a well-studied plant growth promoting rhizo-bacterium (PGPR) significantly increased both aboveground and belowground biomass (DW) and promoted elongation of root, stem and leaf within 17 days following inoculation. Furthermore, the enhanced root growth in PsJN inoculated plants lagged behind the shoot response, resulting in greater allocation to aboveground growth (p = 0.0041). Lower specific root length (SRL, p = 0.0158) and higher specific leaf weight (SLW, p = 0.0029) were also observed in PsJN inoculated seedlings, indicating changes in development. Photosynthetic rates (Ps) were also significantly higher in PsJN inoculated seedlings after 17 days (54%, p = 0.0016), and this occurred initially without increases in stomatal conductance resulting in significantly greater water use efficiency (WUE, 37.7%, p = 0.0467) and lower non-stomatal limitation (LNS, 29.6%, p = 0.0222). These rapid changes in leaf level physiology are at least partially responsible for the growth enhancement due to PsJN. PMID:25461696

  3. The role of silicon in enhancing resistance to bacterial blight of hydroponic- and soil-cultured rice

    Science.gov (United States)

    Song, Alin; Xue, Gaofeng; Cui, Peiyuan; Fan, Fenliang; Liu, Hongfang; Yin, Chang; Sun, Wanchun; Liang, Yongchao

    2016-01-01

    Here we report for the first time that bacterial blight of rice can be alleviated by silicon (Si) added. In both inoculated and uninoculated plants, shoot dry weight was significantly higher in the +Si plants than in the −Si plants. A soil-cultured trial showed that disease severity was 24.3% lower in the Si-amended plants than in the non-Si-amended plants. Plants that were switched from −Si to +Si nutrient solution and simultaneously inoculated with Xoo also exhibited the same high resistance to bacterial blight as the plants that were treated continuously with Si, with control efficiencies of 52.8 and 62.9%, respectively. Moreover, total concentrations of soluble phenolics and lignin in rice leaves were significantly higher in the +Si plants than in the −Si plants. Polyphenoloxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities in rice leaves were observed to be higher in the +Si plants than in the −Si plants. The expression levels of Os03g0109600, Prla, Rcht2 and Lox2osPil, were also higher in +Si plants than in −Si plants post-inoculation during the experimental time. Addition of Si resulted in increased Pal transcription, and inhibited CatA and Os03g0126000 expression in the earlier and later stages of bacterial inoculation, respectively. PMID:27091552

  4. The role of silicon in enhancing resistance to bacterial blight of hydroponic- and soil-cultured rice.

    Science.gov (United States)

    Song, Alin; Xue, Gaofeng; Cui, Peiyuan; Fan, Fenliang; Liu, Hongfang; Yin, Chang; Sun, Wanchun; Liang, Yongchao

    2016-01-01

    Here we report for the first time that bacterial blight of rice can be alleviated by silicon (Si) added. In both inoculated and uninoculated plants, shoot dry weight was significantly higher in the +Si plants than in the -Si plants. A soil-cultured trial showed that disease severity was 24.3% lower in the Si-amended plants than in the non-Si-amended plants. Plants that were switched from -Si to +Si nutrient solution and simultaneously inoculated with Xoo also exhibited the same high resistance to bacterial blight as the plants that were treated continuously with Si, with control efficiencies of 52.8 and 62.9%, respectively. Moreover, total concentrations of soluble phenolics and lignin in rice leaves were significantly higher in the +Si plants than in the -Si plants. Polyphenoloxidase (PPO) and phenylalanine ammonia-lyase (PAL) activities in rice leaves were observed to be higher in the +Si plants than in the -Si plants. The expression levels of Os03g0109600, Prla, Rcht2 and Lox2osPil, were also higher in +Si plants than in -Si plants post-inoculation during the experimental time. Addition of Si resulted in increased Pal transcription, and inhibited CatA and Os03g0126000 expression in the earlier and later stages of bacterial inoculation, respectively. PMID:27091552

  5. Effectiveness of Endophytic Bacterial Consortium of Coffee Plant on Mortality of Pratylenchus Coffeae in Vitro

    OpenAIRE

    dwi halimah; Abdul Munif; Giyanto Giyanto

    2015-01-01

    Bacteria live in wild in form of a consortium. Use of microbial consortium tends to give better results than single isolate, because the action of enzyme of each type of microbe can complement each other in order to survive. This study aimed to study the effectiveness of bacterial endophytic consortium from coffee plant on plant growth and mortality of parasitic nematodes in coffee. Isolation of bacteria is conducted  by growing the crushed roots, stems and leaves of coffee on 20% TSA media, ...

  6. Optimizing EPG settings to record blue-green sharpshooter X waves for future studies of grape host plant resistance to Xf inoculation

    Science.gov (United States)

    The long-term goal of the research reported in this review is to develop methodology for assessment of grapevine resistant to sharpshooter inoculation of Xylella fastidiosa(Xf)into healthy grapevines, thereby preventing Xf infection. Such a trait would be quite different from the more common mechani...

  7. O antigen modulates insect vector acquisition of the bacterial plant pathogen Xylella fastidiosa.

    Science.gov (United States)

    Rapicavoli, Jeannette N; Kinsinger, Nichola; Perring, Thomas M; Backus, Elaine A; Shugart, Holly J; Walker, Sharon; Roper, M Caroline

    2015-12-01

    Hemipteran insect vectors transmit the majority of plant pathogens. Acquisition of pathogenic bacteria by these piercing/sucking insects requires intimate associations between the bacterial cells and insect surfaces. Lipopolysaccharide (LPS) is the predominant macromolecule displayed on the cell surface of Gram-negative bacteria and thus mediates bacterial interactions with the environment and potential hosts. We hypothesized that bacterial cell surface properties mediated by LPS would be important in modulating vector-pathogen interactions required for acquisition of the bacterial plant pathogen Xylella fastidiosa, the causative agent of Pierce's disease of grapevines. Utilizing a mutant that produces truncated O antigen (the terminal portion of the LPS molecule), we present results that link this LPS structural alteration to a significant decrease in the attachment of X. fastidiosa to blue-green sharpshooter foreguts. Scanning electron microscopy confirmed that this defect in initial attachment compromised subsequent biofilm formation within vector foreguts, thus impairing pathogen acquisition. We also establish a relationship between O antigen truncation and significant changes in the physiochemical properties of the cell, which in turn affect the dynamics of X. fastidiosa adhesion to the vector foregut. Lastly, we couple measurements of the physiochemical properties of the cell with hydrodynamic fluid shear rates to produce a Comsol model that predicts primary areas of bacterial colonization within blue-green sharpshooter foreguts, and we present experimental data that support the model. These results demonstrate that, in addition to reported protein adhesin-ligand interactions, O antigen is crucial for vector-pathogen interactions, specifically in the acquisition of this destructive agricultural pathogen. PMID:26386068

  8. Detection of bacterial infection of agave plants by laser-induced fluorescence

    Science.gov (United States)

    Cervantes-Martinez, Jesus; Flores-Hernandez, Ricardo; Rodriguez-Garay, Benjamin; Santacruz-Ruvalcaba, Fernando

    2002-05-01

    Greenhouse-grown plants of Agave tequilana Weber var. azul were inoculated with Erwinia carotovora, the causal agent of stem soft rot. We investigated the laser-induced fluorescence (LIF) of agave plants to determine whether LIF can be used as a noninvasive sensing tool for pathological studies. The LIF technique was also investigated as a means of detecting the effect of the polyamine biosynthesis inhibitor beta-hydroxyethylhydrazine as a bactericide against the pathogenic bacterium Erwinia carotovora. A He-Ne laser at 632.8 nm was used as the excitation source, and in vivo fluorescence emission spectra were recorded in the 660-790-range. Fluorescence maxima were at 690 and 740 nm. The infected plants that were untreated with the bactericide showed a definite increase in fluorescence intensity at both maxima within the first three days after infection. Beginning on the fifth day, a steady decrease in fluorescence intensity was observed, with a greater effect at 740 than at 690 nm. After 30 days there was no fluorescence. The infected plants that had been treated with the bactericide showed no significant change in fluorescence compared with that of the uninfected plants. The ratio of fluorescence intensities was determined to be F 690 nm/F 740 nm for all treatments. These studies indicate that LIF measurements of agave plants may be used for the early detection of certain types of disease and for determining the effect of a bactericide on bacteria. The results also showed that fluorescence intensity ratios can be used as a reliable indicator of the progress of disease.

  9. The olive knot disease as a model to study the role of interspecies bacterial communities in plant disease

    OpenAIRE

    Buonaurio, Roberto; Moretti, Chiaraluce; da Silva, Daniel Passos; Cortese, Chiara; Ramos, Cayo; Venturi, Vittorio

    2015-01-01

    There is an increasing interest in studying interspecies bacterial interactions in diseases of animals and plants as it is believed that the great majority of bacteria found in nature live in complex communities. Plant pathologists have thus far mainly focused on studies involving single species or on their interactions with antagonistic competitors. A bacterial disease used as model to study multispecies interactions is the olive knot disease, caused by Pseudomonas savastanoi pv. savastanoi ...

  10. A Complex Inoculant of N2-Fixing, P- and K-Solubilizing Bacteria from a Purple Soil Improves the Growth of Kiwifruit (Actinidia chinensis) Plantlets.

    Science.gov (United States)

    Shen, Hong; He, Xinhua; Liu, Yiqing; Chen, Yi; Tang, Jianming; Guo, Tao

    2016-01-01

    Limited information is available if plant growth promoting bacteria (PGPB) can promote the growth of fruit crops through improvements in soil fertility. This study aimed to evaluate the capacity of PGPB, identified by phenotypic and 16S rRNA sequencing from a vegetable purple soil in Chongqing, China, to increase soil nitrogen (N), phosphorus (P), and potassium (K) availability and growth of kiwifruit (Actinidia chinensis). In doing so, three out of 17 bacterial isolates with a high capacity of N2-fixation (Bacillus amyloliquefaciens, XD-N-3), P-solubilization (B. pumilus, XD-P-1) or K-solubilization (B. circulans, XD-K-2) were mixed as a complex bacterial inoculant. A pot experiment then examined its effects of this complex inoculant on soil microflora, soil N2-fixation, P- and K-solubility and kiwifruit growth under four treatments. These treatments were (1) no-fertilizer and no-bacterial inoculant (Control), (2) no-bacterial inoculant and a full-rate of chemical NPK fertilizer (CF), (3) the complex inoculant (CI), and (4) a half-rate CF and full CI (1/2CF+CI). Results indicated that significantly greater growth of N2-fixing, P- and K-solubilizing bacteria among treatments ranked from greatest to least as under 1/2CF+CI ≈ CI > CF ≈ Control. Though generally without significant treatment differences in soil total N, P, or K, significantly greater soil available N, P, or K among treatments was, respectively, patterned as under 1/2CF+CI ≈ CI > CF ≈ Control, under 1/2CF+CI > CF > CI > Control or under 1/2CF+CI > CF ≈ CI > Control, indicating an improvement of soil fertility by this complex inoculant. In regards to plant growth, significantly greater total plant biomass and total N, P, and K accumulation among treatments were ranked as 1/2CF+CI ≈ CI > CF > Control. Additionally, significantly greater leaf polyphenol oxidase activity ranked as under CF > 1/2CF+CI ≈ Control ≈ CI, while leaf malondialdehyde contents as under Control > CI ≈ CF > 1/2CF

  11. A Complex Inoculant of N2-Fixing, P- and K-Solubilizing Bacteria from a Purple Soil Improves the Growth of Kiwifruit (Actinidia chinensis) Plantlets

    Science.gov (United States)

    Shen, Hong; He, Xinhua; Liu, Yiqing; Chen, Yi; Tang, Jianming; Guo, Tao

    2016-01-01

    Limited information is available if plant growth promoting bacteria (PGPB) can promote the growth of fruit crops through improvements in soil fertility. This study aimed to evaluate the capacity of PGPB, identified by phenotypic and 16S rRNA sequencing from a vegetable purple soil in Chongqing, China, to increase soil nitrogen (N), phosphorus (P), and potassium (K) availability and growth of kiwifruit (Actinidia chinensis). In doing so, three out of 17 bacterial isolates with a high capacity of N2-fixation (Bacillus amyloliquefaciens, XD-N-3), P-solubilization (B. pumilus, XD-P-1) or K-solubilization (B. circulans, XD-K-2) were mixed as a complex bacterial inoculant. A pot experiment then examined its effects of this complex inoculant on soil microflora, soil N2-fixation, P- and K-solubility and kiwifruit growth under four treatments. These treatments were (1) no-fertilizer and no-bacterial inoculant (Control), (2) no-bacterial inoculant and a full-rate of chemical NPK fertilizer (CF), (3) the complex inoculant (CI), and (4) a half-rate CF and full CI (1/2CF+CI). Results indicated that significantly greater growth of N2-fixing, P- and K-solubilizing bacteria among treatments ranked from greatest to least as under 1/2CF+CI ≈ CI > CF ≈ Control. Though generally without significant treatment differences in soil total N, P, or K, significantly greater soil available N, P, or K among treatments was, respectively, patterned as under 1/2CF+CI ≈ CI > CF ≈ Control, under 1/2CF+CI > CF > CI > Control or under 1/2CF+CI > CF ≈ CI > Control, indicating an improvement of soil fertility by this complex inoculant. In regards to plant growth, significantly greater total plant biomass and total N, P, and K accumulation among treatments were ranked as 1/2CF+CI ≈ CI > CF > Control. Additionally, significantly greater leaf polyphenol oxidase activity ranked as under CF > 1/2CF+CI ≈ Control ≈ CI, while leaf malondialdehyde contents as under Control > CI ≈ CF > 1/2CF

  12. Dietary plant phenolic improves survival of bacterial infection in Manduca sexta caterpillars.

    Science.gov (United States)

    Del Campo, Marta L; Halitschke, Rayko; Short, Sarah M; Lazzaro, Brian P; Kessler, André

    2013-03-01

    Plant phenolics are generally thought to play significant roles in plant defense against herbivores and pathogens. Many plant taxa, including Solanaceae, are rich in phenolic compounds and some insect herbivores have been shown to acquire phenolics from their hosts to use them as protection against their natural enemies. Here we demonstrate that larvae of an insect specialist on Solanaceae, the tobacco hornworm, Manduca sexta L. (Lepidoptera: Sphingidae), acquire the plant phenolic chlorogenic acid (CA), and other caffeic acid derivatives as they feed on one of their hosts, Nicotiana attenuata L. (Solanaceae), and on artificial diet supplemented with CA. We test the hypothesis that larvae fed on CA-supplemented diet would have better resistance against bacterial infection than larvae fed on a standard CA-free diet by injecting bacteria into the hemocoel of fourth instars. Larvae fed CA-supplemented diet show significantly higher survival of infection with Enterococcus faecalis (Andrewes & Horder) Schleifer & Kilpper-Bälz, but not of infection with the more virulent Pseudomonas aeruginosa (Schroeter) Migula. Larvae fed on CA-supplemented diet possess a constitutively higher number of circulating hemocytes than larvae fed on the standard diet, but we found no other evidence of increased immune system activity, nor were larvae fed on CA-supplemented diet better able to suppress bacterial proliferation early in the infection. Thus, our data suggest an additional defensive function of CA to the direct toxic inhibition of pathogen proliferation in the gut. PMID:23420018

  13. Plant-Associated Bacterial Degradation of Toxic Organic Compounds in Soil

    Directory of Open Access Journals (Sweden)

    David Dowling

    2009-08-01

    Full Text Available A number of toxic synthetic organic compounds can contaminate environmental soil through either local (e.g., industrial or diffuse (e.g., agricultural contamination. Increased levels of these toxic organic compounds in the environment have been associated with human health risks including cancer. Plant-associated bacteria, such as endophytic bacteria (non-pathogenic bacteria that occur naturally in plants and rhizospheric bacteria (bacteria that live on and near the roots of plants, have been shown to contribute to biodegradation of toxic organic compounds in contaminated soil and could have potential for improving phytoremediation. Endophytic and rhizospheric bacterial degradation of toxic organic compounds (either naturally occurring or genetically enhanced in contaminated soil in the environment could have positive implications for human health worldwide and is the subject of this review.

  14. Plant-associated bacterial degradation of toxic organic compounds in soil.

    LENUS (Irish Health Repository)

    McGuinness, Martina

    2009-08-01

    A number of toxic synthetic organic compounds can contaminate environmental soil through either local (e.g., industrial) or diffuse (e.g., agricultural) contamination. Increased levels of these toxic organic compounds in the environment have been associated with human health risks including cancer. Plant-associated bacteria, such as endophytic bacteria (non-pathogenic bacteria that occur naturally in plants) and rhizospheric bacteria (bacteria that live on and near the roots of plants), have been shown to contribute to biodegradation of toxic organic compounds in contaminated soil and could have potential for improving phytoremediation. Endophytic and rhizospheric bacterial degradation of toxic organic compounds (either naturally occurring or genetically enhanced) in contaminated soil in the environment could have positive implications for human health worldwide and is the subject of this review.

  15. Bacterial communities associated with the pitcher fluids of three Nepenthes (Nepenthaceae) pitcher plant species growing in the wild.

    Science.gov (United States)

    Chou, Lee Yiung; Clarke, Charles M; Dykes, Gary A

    2014-10-01

    Nepenthes pitcher plants produce modified jug-shaped leaves to attract, trap and digest insect prey. We used 16S rDNA cloning and sequencing to compare bacterial communities in pitcher fluids of each of three species, namely Nepenthes ampullaria, Nepenthes gracilis and Nepenthes mirabilis, growing in the wild. In contrast to previous greenhouse-based studies, we found that both opened and unopened pitchers harbored bacterial DNA. Pitchers of N. mirabilis had higher bacterial diversity as compared to other Nepenthes species. The composition of the bacterial communities could be different between pitcher types for N. mirabilis (ANOSIM: R = 0.340, p Nepenthes species had similar bacterial composition between pitcher types. SIMPER showed that more than 50 % of the bacterial taxa identified from the open pitchers of N. mirabilis were not found in other groups. Our study suggests that bacteria in N. mirabilis are divided into native and nonnative groups. PMID:25005571

  16. Bacterial structure and characterization of plant growth promoting and oil degrading bacteria from the rhizospheres of mangrove plants.

    Science.gov (United States)

    do Carmo, Flávia Lima; dos Santos, Henrique Fragoso; Martins, Edir Ferreira; van Elsas, Jan Dirk; Rosado, Alexandre Soares; Peixoto, Raquel Silva

    2011-08-01

    Most oil from oceanic spills converges on coastal ecosystems, such as mangrove forests, which are threatened with worldwide disappearance. Particular bacteria that inhabit the rhizosphere of local plant species can stimulate plant development through various mechanisms; it would be advantageous if these would also be capable of degrading oil. Such bacteria may be important in the preservation or recuperation of mangrove forests impacted by oil spills. This study aimed to compare the bacterial structure, isolate and evaluate bacteria able to degrade oil and stimulate plant growth, from the rhizospheres of three mangrove plant species. These features are particularly important taking into account recent policies for mangrove bioreme-diation, implying that oil degradation as well as plant maintenance and health are key targets. Fifty-seven morphotypes were isolated from the mangrove rhizospheres on Bushneil-Haas (BH) medium supplemented with oil as the sole carbon source and tested for plant growth promotion. Of this strains, 60% potentially fixed nitrogen, 16% showed antimicrobial activity, 84% produced siderophores, 51% had the capacity to solubilize phosphate, and 33% produced the indole acetic acid hormone. Using gas chromatography, we evaluated the oil-degrading potential of ten selected strains that had different morphologies and showed Plant Growth Promoting Rhizobacteria (PGPR) features. The ten tested strains showed a promising degradation profile for at least one compound present in the oil. Among degrader strains, 46% had promising PGPR potential, having at least three of the above capacities. These strains might be used as a consortium, allowing the concomitant degradation of oil and stimulation of mangrove plant survival and maintenance. PMID:21887634

  17. Seasonal Changes in Bacterial Communities Cause Foaming in a Wastewater Treatment Plant.

    Science.gov (United States)

    Wang, Ping; Yu, Zhisheng; Zhao, Jihong; Zhang, Hongxun

    2016-04-01

    Bio-foaming is a major problem in solid separation in activated sludge (AS) wastewater treatment systems. Understanding the changes in bacterial communities during sludge foaming is vital for explaining foam formation. Changes in bacterial communities in the foam, corresponding foaming AS, and non-foaming AS in a seasonal foaming wastewater treatment plant (WWTP) in Northern China were investigated by high-throughput pyrosequencing and molecular quantification-based approaches. We found that bacterial communities of the foam and the corresponding foaming AS were similar but markedly different from those of the non-foaming AS. Actinobacteria was the predominant phylum in the foam and the corresponding foaming AS, whereas Proteobacteria was predominant in the non-foaming AS. Similar to the results of most previous studies, our results showed that Candidatus "Microthrix parvicella" was the predominant filamentous bacteria in the foam and the corresponding foaming AS and was significantly enriched in the foam compared to the corresponding foaming AS. Its abundance decreased gradually with a slow disappearance of sludge foaming, indicating that its overgrowth had a direct relationship with sludge foaming. In addition to Candidatus M. parvicella, Tetrasphaera and Trichococcus might play a role in sludge foaming, because they supported the changes in AS microbial ecology for foam formation. The effluent water quality of the surveyed plant remained stable during the period of sludge foaming, but the microbial consortia responsible for nitrogen and phosphorus transformation and removal markedly changed compared to that in the non-foaming AS. This study adds to the previous understanding of bacterial communities causing foaming in WWTPs. PMID:26577577

  18. Aumento da eficiência nutricional de tomateiros inoculados com bactérias endofíticas promotoras de crescimento Increased nutritional efficiency of tomato plants inoculated with growth-promoting endophytic bacteria

    Directory of Open Access Journals (Sweden)

    Patrícia Baston Barretti

    2008-08-01

    Clara. Fifty five days after transplanting the upper portion of the cut seedlings, the plants were collected to determine the dry matter of the aerial parts and concentration of macro and micro nutrients. The concentration of N, P, K, Ca, Mg, Cu and Zn in the shoot and N, P, Mg and Mn in roots of inoculated plants differed from non-inoculated controls. Endophytic bacteria Micrococcus sp. (UFLA 11-LS and Brevundimonas sp. (UFV-E49 were identified by sequencing of the 16S ribosomal DNA. The P uptake in plants inoculated with these isolates was higher than in the non-inoculated controls. Plants treated with the first isolate were more efficient in the use of N, P, K, Ca, Mg, S, Cu, Fe, and Zn. The highest concentration of N, P, K, Mg, and Zn were found in the shoot of plants inoculated with Brevundimonas sp. The results of this study indicate that these endophytic bacteria isolates may be employed to increase the nutritional efficiency of tomato plants.

  19. The bacterial pathogen Xylella fastidiosa affects the leaf ionome of plant hosts during infection.

    Science.gov (United States)

    De La Fuente, Leonardo; Parker, Jennifer K; Oliver, Jonathan E; Granger, Shea; Brannen, Phillip M; van Santen, Edzard; Cobine, Paul A

    2013-01-01

    Xylella fastidiosa is a plant pathogenic bacterium that lives inside the host xylem vessels, where it forms biofilm believed to be responsible for disrupting the passage of water and nutrients. Here, Nicotiana tabacum was infected with X. fastidiosa, and the spatial and temporal changes in the whole-leaf ionome (i.e. the mineral and trace element composition) were measured as the host plant transitioned from healthy to diseased physiological status. The elemental composition of leaves was used as an indicator of the physiological changes in the host at a specific time and relative position during plant development. Bacterial infection was found to cause significant increases in concentrations of calcium prior to the appearance of symptoms and decreases in concentrations of phosphorous after symptoms appeared. Field-collected leaves from multiple varieties of grape, blueberry, and pecan plants grown in different locations over a four-year period in the Southeastern US showed the same alterations in Ca and P. This descriptive ionomics approach characterizes the existence of a mineral element-based response to X. fastidiosa using a model system suitable for further manipulation to uncover additional details of the role of mineral elements during plant-pathogen interactions. This is the first report on the dynamics of changes in the ionome of the host plant throughout the process of infection by a pathogen. PMID:23667547

  20. Phyllosphere and carposphere bacterial communities in olive plants subjected to different cultural practices

    Directory of Open Access Journals (Sweden)

    Silvia Pascazio

    2015-09-01

    Full Text Available The aim of this study was to characterize phyllosphere and carposphere bacterial communities of olive trees subjected for 13 years to two different soil management systems (sustainable and conventional in a mature olive grove located in Southern Italy. Amplified DNA fragments of the 16S ribosomal RNA eubacterial gene (16S rRNA of bacteria living on leaf and fruit surface, and in fruit pulp were analyzed by denaturing gradient gel electrophoresis (DGGE. A clone library of 16S rRNA amplicons extracted from the bacteria living in pulp homogenates and a phylogenetic analysis were performed. Generally, the DGGE patterns of the bacteria from both the treatments clustered separately. The medium-term sustainable orchard management resulted in a higher number of bacterial species from olive fruit pulp. Phyllosphere and carposphere communities evaluated by DGGE were affected by the type of the agricultural practices adopted. A better understanding of phyllosphere and carposphere microbiota of cultivated olive plants could be useful for the promotion of plant growth, a better plant protection and a higher crop quality.

  1. Bacterial community structure and variation in a full-scale seawater desalination plant for drinking water production.

    Science.gov (United States)

    Belila, A; El-Chakhtoura, J; Otaibi, N; Muyzer, G; Gonzalez-Gil, G; Saikaly, P E; van Loosdrecht, M C M; Vrouwenvelder, J S

    2016-05-01

    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 m(3)/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

  2. Bacterial community structure and variation in a full-scale seawater desalination plant for drinking water production

    KAUST Repository

    Belila, A.

    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

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

    Directory of Open Access Journals (Sweden)

    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.

  4. Analysis of bacterial community in two wastewater treatment plants by denaturing gradient gel electrophoresis and fluorescent in situ hybridization

    International Nuclear Information System (INIS)

    A combination of denaturing gradient gel electrophoresis (DGGE) and oligonucleotide probes was used to characterize and follow the dynamic of bacterial community in two wastewater treatment plants with an A2 O system of each plant. To complete this technique, we used Fluorescent in situ Hybridization (FISH) to quantify the main groups in activated sludges samples. (Author)

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

    Directory of Open Access Journals (Sweden)

    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

  6. EFFECT OF ROOT EXUDATES OF SENGON PLANT (Paraserianthes falcataria L. Nielsen) INOCULATED WITH FUNGAL ENDOPHYTE, Nigrospora sp. ON CONTROL OF ROOT-KNOT NEMATODE Meloidogyne spp.???

    OpenAIRE

    Nur, Amin

    2012-01-01

    Endophytic fungi are fungi that live within their host plant tissues without causing any symptoms on the host. A host plant and endophytic fungi living on it have a mutulistic relathionship. The host provides substrate and space for the endophytes to grow while the fungal endophytes promote plant growth and protect the plant hosts from pests and diseases. The research was aimed to determine the effect of different concentrations of root exudates of sengon plant (Paraserianthes falcataria) ...

  7. The use of 32P dilution techniques to evaluate the effect of mycorrhizal inoculation on plant uptake of P from products of fermentation mixtures including agrowastes, Aspergillus niger and rock phosphate

    International Nuclear Information System (INIS)

    Some microorganisms, such as filamentous fungi, are capable of solubilizing rock phosphate products, which are a less costly alternative to conventional P fertilizers used so far in agriculture. However, metabolizable C compounds must be supplied to the microbes to solubilize rock phosphate (RP). On another hand, huge quantities of organic materials are produced by cultivated plants every year and their residues became agrowastes, which may often pose significant environmental problems. An attractive approach to solubilize RP would therefore, be the application of microorganisms possessing a high acid-producing activity in fermentation processes based on agrowastes. In this context, Aspergillus niger was successfully cultivated on sugar beet (SB) waste material supplemented with 3.0 g/l RP acidifying the medium by releasing citric acid and thus decreasing the pH to 3.0-3.5. At the end of the solid-state fermentation process, the product contained mineralized (69%) organic matter, RP solubilized to 224 μg/ml and fungal mycelium. A series of microcosms greenhouse experiments were then carried out aimed at evaluating the effectiveness of such product, added at a rate of 5% (v/v), to a neutral, calcareous, P-deficient soil. Clover (Trifolium repens) inoculated or not with an arbuscular mycorrhizal fungus, was the test plant. It was shown that the product improved plant growth and P acquisition. Mycorrhizal inoculation further enhanced the effectiveness of the fermentation product. The use of the isotopic 32 P dilution technique showed a lowering of the specific activity of the treated plants, thus indicating that plants benefited from P solublilized from RP by the microbial treatments applied in this experiment. The reported biotechnological approach offers a potential application for sustainability purposes. (author)

  8. The use of 32P dilution techniques to evaluate the effect of mycorrhizal inoculation on plant uptake of P from products of fermentation mixtures including agrowastes, Aspergillus niger and rock phosphate

    International Nuclear Information System (INIS)

    Some microorganisms, such as filamentous fungi, are capable of solubilizing rock phosphate products, which are a less costly alternative to conventional P fertilizers used so far in agriculture. However, metabolizable C compounds must be supplied to the microbes to solubilize rock phosphate (RP). On another hand, huge quantities of organic materials are produced by cultivated plants every year and their residues became agrowastes, which may often pose significant environmental problems. An attractive approach to solubilize RP would therefore, be the application of microorganisms possessing a high acid-producing activity in fermentation processes based on agrowastes. In this context, Aspergillus niger was successfully cultivated on sugar beet (SB) waste material supplemented with 3.0 g/l RP acidifying the medium by releasing citric acid and thus decreasing the pH to 3.0-3.5. At the end of the solid-state fermentation process, the product contained mineralized (69%) organic matter, RP solubilized to 224 μg/ml and fungal mycelium. A series of microcosms greenhouse experiments were then carried out aimed at evaluating the effectiveness of such product, added at a rate of 5% (v/v), to a neutral, calcareous, P-deficient soil. Clover (Trifolium repens) inoculated or not with an arbuscular mycorrhizal fungus, was the test plant. It was shown that the product improved plant growth and P acquisition. Mycorrhizal inoculation further enhanced the effectiveness of the fermentation product. The use of the isotopic 32 P dilution technique showed a lowering of the specific activity of the treated plants, thus indicating that plants benefited from P solubilized from RP by the microbial treatments applied in this experiment. The reported biotechnological approach offers a potential application for sustainability purposes. (author)

  9. Characterization of N/sub 2/-fixing bacteria and their role in plant growth under humic acid treatment

    International Nuclear Information System (INIS)

    Diazo trophic bacteria isolated from rice belonged to the six genera i.e. Pseudomonas, Azospirillum, Azotobacter, Xanthobacter, Flavobacterium and Zoogloea. During reinoculation studies it was observed that the rice roots grow well under humic acid treatment. The maximum root length 49.5 cm, was recorded at 10 ppm in plants inoculated with Azospirillum strain K-1. The total plant dry weight increase was also observed with the same organism at the similar humic acid concentration. In wheat the bacterial inoculation or humic acid treatment separately increased the dry weight of plant, however the humic acid treatment followed by inoculation of bacteria always cause decrease in total dry weight of plants. (author)

  10. Pepino (Solanum muricatum) planting increased diversity and abundance of bacterial communities in karst area.

    Science.gov (United States)

    Hu, Jinxiang; Yang, Hui; Long, Xiaohua; Liu, Zhaopu; Rengel, Zed

    2016-01-01

    Soil nutrients and microbial communities are the two key factors in revegetation of barren environments. Ecological stoichiometry plays an important role in ecosystem function and limitation, but the relationships between above- and belowground stoichiometry and the bacterial communities in a typical karst region are poorly understood. We used pepino (Solanum muricatum) to examine the stoichiometric traits between soil and foliage, and determine diversity and abundance of bacteria in the karst soil. The soil had a relatively high pH, low fertility, and coarse texture. Foliar N:P ratio and the correlations with soil nitrogen and phosphorus suggested nitrogen limitation. The planting of pepino increased soil urease activity and decreased catalase activity. Higher diversity of bacteria was determined in the pepino rhizosphere than bulk soil using a next-generation, Illumina-based sequencing approach. Proteobacteria, Acidobacteria, Actinobacteria and Bacteroidetes were the dominant phyla in all samples, accounting for more than 80% of the reads. On a genus level, all 625 detected genera were found in all rhizosphere and bulk soils, and 63 genera showed significant differences among samples. Higher Shannon and Chao 1 indices in the rhizosphere than bulk soil indicated that planting of pepino increased diversity and abundance of bacterial communities in karst area. PMID:26902649

  11. Benefits of inoculation with azotobacter in the growth and production of tomato and peppers

    Directory of Open Access Journals (Sweden)

    Jarak Mirjana N.

    2010-01-01

    Full Text Available The aim of this research was to investigate the effects of Azotobacter chroococcum in tomato and pepper growth and production by using two types of inoculation - seed inoculation and seedling inoculation. The effect of inoculation was observed thirty days after sowing, thirty days after transplanting, and in the phase of technological maturity. The following were measured: height of the plants, dry matter of the plants and number and the weight of the fruits. Inoculation had a positive effect on these in both plants. With tomato, better results were achieved when seedlings were inoculated. With pepper, the length of the plant and the dry matter were greater with seedling inoculation, whereas the number and the weight of the fruits were greater with seed inoculation.

  12. Measurement strategies for the determination of airborne bacterial endotoxin in sewage treatment plants.

    Science.gov (United States)

    Thorn, Jörgen; Beijer, Lena; Jonsson, Titti; Rylander, Ragnar

    2002-08-01

    Working in sewage plants can involve exposure to different types of microorganisms, viruses and chemicals. The purpose of this study was to evaluate different measurement strategies to determine airborne bacterial endotoxin in such plants. Sewage treatment plants in three municipalities in western Sweden were included. Measurements of airborne endotoxin were performed in April-May and September-October 2001 using personal and stationary samplers. The air sampling times ranged from 60 to 444 min. In stationary and personal sampler measurements, the amounts of airborne endotoxin detected were generally low. At specific worksites, however, higher endotoxin values were identified, with the highest values at worksites located indoors. The results suggest that the exposure situation is relatively stable over a short time period at a specific worksite and that higher values can be recorded during work practices where agitation of wastewater occurs. The results further suggest that airborne endotoxin exposure situations in sewage treatment plants are complex. Sampling techniques, indoor/outdoor measurements and identification of specific worksites/tasks where there is a risk of airborne endotoxin exposure are important factors that must be considered in order to obtain relevant exposure determinations and establish preventive measures from a health risk perspective. PMID:12176770

  13. Biodegradation of atrazine in transgenic plants expressing a modified bacterial atrazine chlorohydrolase (atzA) gene.

    Science.gov (United States)

    Wang, Lin; Samac, Deborah A; Shapir, Nir; Wackett, Lawrence P; Vance, Carroll P; Olszewski, Neil E; Sadowsky, Michael J

    2005-09-01

    Atrazine is one of the most widely used herbicides in the USA. Atrazine chlorohydrolase (AtzA), the first enzyme in a six-step pathway leading to the mineralization of atrazine in Gram-negative soil bacteria, catalyses the hydrolytic dechlorination and detoxification of atrazine to hydroxyatrazine. In this study, we investigated the potential use of transgenic plants expressing atzA to take up, dechlorinate and detoxify atrazine. Alfalfa, Arabidopsis thaliana and tobacco were transformed with a modified bacterial atzA gene, p-atzA, under the control of the cassava vein mosaic virus promoter. All transgenic plant species actively expressed p-atzA and grew over a wide range of atrazine concentrations. Thin layer chromatography analyses indicated that in planta expression of p-atzA resulted in the production of hydroxyatrazine. Hydroponically grown transgenic tobacco and alfalfa dechlorinated atrazine to hydroxyatrazine in leaves, stems and roots. Moreover, p-atzA was found to be useful as a conditional-positive selection system to isolate alfalfa and Arabidopsis transformants following Agrobacterium-mediated transformation. Our work suggests that the in planta expression of p-atzA may be useful for the development of plants for the phytoremediation of atrazine-contaminated soils and soil water, and as a marker gene to select for the integration of exogenous DNA into the plant genome. PMID:17173634

  14. mADP-RTs: Versatile virulence factors from bacterial pathogens of plants and mammals

    Directory of Open Access Journals (Sweden)

    Lennart eWirthmueller

    2012-06-01

    Full Text Available Mono ADP-ribosyltransferases (mADP-RTs are a family of enzymes that cleave NAD+ and covalently attach the ADP-ribosyl moiety to target proteins. mADP-RTs are well established as important virulence factors of bacteria that infect mammals. Cholera toxin, pertussis toxin and diphteria toxin are three of the best-known examples of mADP-RTs. They modify host target proteins in order to promote infection and/or killing of the host cell. Despite low sequence similarity at the primary amino acid level, mADP-RTs share a conserved core catalytic fold and structural biology has made important contributions to elucidating how mADP-RTs modify mammalian host targets. Recently, mADP-RTs were shown to be present in plant pathogenic bacteria, suggesting that mADP-RTs are also important virulence factors of plant pathogens. Crystal structures of plant pathogenic bacterial mADP-RTs are also now available. Here we review the structure/function of mADP-RTs from pathogens of mammals and plants, highlighting both commonalities and differences.

  15. Alterações metabólicas em plantas de feijão originadas de sementes microbiolizadas por Pseudomonas sp. e inoculadas com Xanthomonas axonopodis pv. phaseoli Metabolic alterations on bean plants originated from microbiolization of seeds with Pseudomonas sp. and inoculated with Xanthomnas axonopodis pv. phaseoli

    Directory of Open Access Journals (Sweden)

    Eliane Gonçalves da Silva

    2009-06-01

    . Em relação à atividade de PO houve redução da mesma nas plantas tratadas com o isolado de Pseudomonas (DFs842. Esses resultados evidenciaram que a microbiolização das sementes provocou alterações metabólicas nas plantas delas originadas, pelo aumento do teor de PST e atividade de PPO, indicando uma provável participação destas enzimas na indução de resistência ativada pela microbiolização com o isolado de Pseudomonas (DFs842.Many enzymes are involved in plant defense against pathogens. The purpose of this study was to verify alterations in activity of some enzymes in bean plants originated from microbiolization of seeds with a fluorescent isolate (DFs842 of Pseudomonas. Bean seeds (cv. "BRS Valente" were immersed in a bacterial suspension of a 24 hours old Pseudomonas culture (OD540=0,5 known as a Xanthomonas axonopodis pv. phaseoli biocontroler. Check treatment consisted of seeds immersed in a saline solution (NaCl 0,85%. After microbiolization for 5 hours at 10ºC, seeds were sowed in a non sterilized substrate composed of soil, sand and bovine manure mixture (3:1:1 ratio disposed in pots in a greenhouse. The pathogen was inoculated by cutting the third true leaves with scissors previously immersed in the bacterial suspension (X. axonopodis pv. phaseoli prepared from a 24 hours old culture (OD540=0,4. Plants were kept in moister chambers for 24 hours before and after the inoculation. For protein extraction preparation, the three true leaves were collected individually at five different times: immediately before inoculation and 6, 24, 72 hours and 15 days after inoculation. The leaf extract was used for determination of total soluble proteins (TSP, and the activity of polyphenol oxidase (PPO and peroxidase (PO by spectrophometry. The results showed a significant increase in TSP content and PPO activity in plants treated with the isolated DFs842, when TSP content was the double of the non-treated plants. It was also observed that, even before

  16. 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.

  17. Isolation of 12 Bacterial endophytes from some mangrove plants and determination of, antimicrobial properties of the isolates and the plant extracts

    OpenAIRE

    Ibrahim M.S Eldeen

    2014-01-01

    The mangrove designates a highly productive ecosystem with important economic and environmental functions. Endophytes are microorganisms that live in the intercellular spaces of plant tissue. This study aimed to isolate and identify bacterial endophytes from five mangrove plants and to determine, antimicrobial properties of the isolates and the plant extracts against four pathogenic bacteria: Bacillus cereus, Staphylococcus aureus, Escherichia coli and Salmonella typhimurium using the deferr...

  18. Bacterial symbionts of a devastating coffee plant pest, the stinkbug Antestiopsis thunbergii (Hemiptera: Pentatomidae).

    Science.gov (United States)

    Matsuura, Yu; Hosokawa, Takahiro; Serracin, Mario; Tulgetske, Genet M; Miller, Thomas A; Fukatsu, Takema

    2014-06-01

    Stinkbugs of the genus Antestiopsis, so-called antestia bugs or variegated coffee bugs, are notorious pests of coffee plants in Africa. We investigated the symbiotic bacteria associated with Antestiopsis thunbergii, a major coffee plant pest in Rwanda. PCR, cloning, sequencing, and phylogenetic analysis of bacterial genes identified four distinct bacterial lineages associated with A. thunbergii: a gammaproteobacterial gut symbiont and symbionts representing the genera Sodalis, Spiroplasma, and Rickettsia. In situ hybridization showed that the gut symbiont densely occupied the lumen of midgut crypts, whereas the Sodalis symbiont, the Spiroplasma symbiont, and the Rickettsia symbiont sparsely and sporadically infected various cells and tissues. Diagnostic PCR survey of 154 A. thunbergii individuals collected at 8 localities in Rwanda revealed high infection frequencies (100% for the gut symbiont, 51.3% for the Sodalis symbiont, 52.6% for the Spiroplasma symbiont, and 24.0% for the Rickettsia symbiont). These results suggest that the gut symbiont is the primary symbiotic associate of obligate nature for A. thunbergii, whereas the Sodalis symbiont, the Spiroplasma symbiont, and the Rickettsia symbiont are the secondary symbiotic associates of facultative nature. We observed high coinfection frequencies, i.e., 7.8% of individuals with quadruple infection with all the symbionts, 32.5% with triple infections with the gut symbiont and two of the secondary symbionts, and 39.6% with double infections with the gut symbiont and any of the three secondary symbionts, which were statistically not different from the expected coinfection frequencies and probably reflected random associations. The knowledge of symbiotic microbiota in A. thunbergii will provide useful background information for controlling this devastating coffee plant pest. PMID:24727277

  19. Airborne peptidoglycans as a supporting indicator of bacterial contamination in a metal processing plant

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    Marcin Cyprowski

    2016-03-01

    Full Text Available Objectives: The aim of this study was to assess exposure to airborne endotoxins and peptidoglycans (PGs as well as possibility of using PGs as a surrogate measure of bacterial exposure in workplaces in a metal processing plant. Material and Methods: Personal dosimetry (N = 11 was used to obtain data on concentrations of viable bacteria, total number of bioaerosol particles, endotoxins and peptidoglycans. To investigate the size distributions of aerosol particles responsible for transport of endotoxins and PGs, air samples (N = 5 were additionally collected using the 8-stage cascade impactor. Endotoxins and PGs were assayed with the Limulus amebocyte lysate (LAL test and a kinetic version of the silkworm larvae plasma (SLP test, respectively. Results: Median concentrations of airborne PGs (14.6 ng/m3, endotoxins (0.2 ng/m3, viable bacteria (1.16×103 CFU/m3 and the total number of bioaerosol particles (1.81×106 cells/m3 were determined. Qualitative analysis revealed presence of 19 bacterial species belonging to 14 genera. The calculations showed strong, significant correlations (p < 0.05 between endotoxins, viable bacteria (r = 0.75 and the total number of bioaerosol particle concentrations (r = 0.76 as well as between PGs and the total number of bioaerosol particle concentrations (r = 0.72. Size distribution analysis showed that the highest concentrations of bacterial aerosols occurred in the range of 2.1–3.3 μm. In the case of endotoxins, an increase of concentrations in 2 ranges of aerodynamic diameters: 1.1–3.3 μm and 5.8–9 μm was shown. For PGs there was a visible gradual increase of their concentrations in the range 2.1–9 μm. Conclusions: Peptidoglycans can be treated as a supporting indicator of bacterial contamination in metal processing plants, particularly when an assessment of an immunotoxic potential of microbiological hazards needs to be performed. However, to be extrapolated to other occupational and non

  20. Perspectives of bacterial ACC deaminase in phytoremediation.

    Science.gov (United States)

    Arshad, Muhammad; Saleem, Muhammad; Hussain, Sarfraz

    2007-08-01

    Phytoremediation of contaminated soil and water environments is regulated and coordinated by the plant root system, yet root growth is often inhibited by pollutant-induced stress. Prolific root growth could maximize rates of hyperaccumulation of inorganic contaminants or rhizodegradation of organic pollutants, and thus accelerate phytoremediation. Accelerated ethylene production in response to stress induced by contaminants is known to inhibit root growth and is considered as a major limitation in improving phytoremediation efficiency. Recent work shows that bacterial 1-aminocyclopropane-1-carboxylate (ACC) deaminase regulates ethylene levels in plants by metabolizing its precursor ACC into alpha-ketobutyric acid and ammonia. Plants inoculated with ACC deaminase bacteria or transgenic plants that express bacterial ACC deaminase genes can regulate their ethylene levels and consequently contribute to a more extensive root system. Such proliferation of roots in contaminated soil can lead to enhanced uptake of heavy metals or rhizodegradation of xenobiotics. PMID:17573137

  1. Degradabilidade in situ de silagens de milho confeccionadas com inoculantes bacteriano e/ou enzimático - DOI: 10.4025/actascianimsci.v28i1.658 In situ degradability of corn silages prepared with bacterial and/or enzymatic inoculants - DOI: 10.4025/actascianimsci.v28i1.658

    Directory of Open Access Journals (Sweden)

    Elzânia Sales Pereira

    2006-01-01

    Full Text Available O objetivo deste trabalho foi avaliar os efeitos de inoculantes bacterianos e/ou enzimáticos sobre a degradabilidade ruminal da silagem de milho. Foi utilizada a técnica in situ, em quatro bovinos adultos, distribuídos em quadrado latino 4x4. Os tratamentos avaliados foram: SC (silagem controle, SIB (silagem com inoculante bacteriano, SIBE (silagem com inoculante bacteriano e enzimático e SIE (silagem com inoculante enzimático. Não houve diferença entre tratamentos nas frações solúvel (a, potencialmente degradável (b, taxa de degradação da fração b (c, degradabilidade potencial (DP e degradabilidade efetiva (DE da MS e MO. A DE da PB foi maior para o tratamento SIE (63,13% e menor para o tratamento SIBE (53,69%. A fração b da FDN apresentou maior valor para SIBE (74,13% e menor para SIB (64,07%. O resíduo indigerido (I da FDN não diferiu entre os tratamentos. As frações b e I e a taxa c da FDA não diferiram entre os tratamentos. Palavras-chave: degradação, fibra, matéria orgânica, matéria seca, proteína bruta.The objective of this work was to evaluate the effects of the bacterial and/or enzymatic inoculants on corn silage degradation. The in situ technique was used in four adult steers in a 4x4 latin square design. The evaluated treatments were: CS (control silage, SBI (silage with bacterial inoculant, SBEI (silage with bacterial and enzymatic inoculant and SEI (silage with enzymatic inoculant. There was no difference among treatments in soluble fraction (a, potential degradable fraction (b, fraction b rate of degradation (c, potential degradability (PD and effective degradability (ED of DM and OM. The ED of CP was higher in SEI treatment (63.13% and lower in SBEI treatment (53.69%. The b fraction of NDF was higher for SBEI (74.13% and lower for SBI (64.07%. The NDF indigestible residue (I did not show any difference among treatments. The ADF b and I fraction and the c rate values did not show any difference among

  2. Inoculante enzimático-bacteriano, composição química e parâmetros fermentativos das silagens dos capins Tanzânia e Mombaça Enzymatic-bacterial inoculants, chemical composition and fermentation characteristics of Tanzaniagrass and Mombaçagrass silages

    Directory of Open Access Journals (Sweden)

    Rogério Marchiori Coan

    2005-04-01

    Full Text Available Objetivou-se, com o presente trabalho, avaliar os efeitos de idades de colheita e do uso de inoculante enzimático-bacteriano sobre os parâmetros de fermentação, de composição química e digestibilidade in vitro da matéria seca (DIVMS das silagens dos cultivares Tanzânia e Mombaça (Panicum maximum Jacq.. As forragens foram colhidas aos 45 e 60 dias após o corte de uniformização, submetidas a dois tratamentos (A - Ensilagem sem aditivo [Controle]; B - Ensilagem com adição de inoculante enzimático-bacteriano e distribuídas em um delineamento inteiramente casualizado em esquema fatorial (dois capins x duas inoculações x duas idades de corte, com três repetições. O conteúdo de MS das silagens confeccionadas com as plantas colhidas aos 60 dias de rebrota foi superior àquele das silagens colhidas com 45 dias. As silagens confeccionadas com as plantas colhidas aos 45 dias de rebrota apresentaram os maiores teores de PB (11,9%. Não se observaram efeitos das silagens, dos tratamentos e das idades de corte sobre os teores de hemicelulose, celulose e DIVMS e valores de pH e N-NH3. As silagens do capim-tanzânia apresentaram os maiores teores de MS, FDN, FDA, ácido lático e ácido butírico, enquanto as de capim-mombaça, os de PB e de ácido acético. A adição de inoculante enzimático-bateriano promoveu silagens com menores teores de MS, PB e lignina que as não-tratadas. Os capins tanzânia e mombaça não apresentaram limitações ao processo de ensilagem. O inoculante enzimático-bacteriano não melhorou as características qualitativas, fermentativas e nutricionais das silagens avaliadas.The objective of this trial was to evaluate the effect of the harvest time (45 or 60 days of regrowth, and enzymatic-bacterial inoculants on the fermentation characteristics, chemical composition, in vitro dry matter digestibility (IVDMD of silages from Tanzânia and Mombaça (Panicum maximum Jacq. cultivars. Forages, cut in the different

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

    International Nuclear Information System (INIS)

    Organic components leaked from Sorghum bicolor seedlings ('root exudates') were examined by recovering 14C labelled compounds from root solutions of seedlings inoculated with Azospirillum brasilense, Azotobacter vinelandii or Klebsiella pneumoniae nif-. Up to 3.5% of the total 14C recovered from shoots, roots, and nutrient solutions was found in the root solutions. Inoculation with Azospirillum and Azotobacter increased the amounts of 14C and decreased the amounts of carbohydrates in the root solutions. When sucrose was added as a carbon source for the bacteria, the increase of 14C in the solutions did not occur. Quantities of 14C 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 14CO2, about 15% of the total 14C recovered within 48 hours exposure was found in soil leachates. (orig.)

  4. Adaptation of Oil Palm Seedlings Inoculated with Arbuscular Mycorrhizal Fungi and Mycorrhizal Endosymbiotic Bacteria Bacillus subtilis B10 towards Biotic Stress of Pathogen Ganoderma boninense Pat

    Directory of Open Access Journals (Sweden)

    YENNI BAKHTIAR

    2012-12-01

    Full Text Available The effects of mycorrhizal endosymbiotic bacteria Bacillus subtilis B10 and composite of arbuscular mycorrhizal fungal spores in green house experiment were examined in order to evaluate their effectiveness and compatibility with oil palm seedlings in the presence of a fungal pathogen Ganoderma boninense, the most serious pathogen in oil palm (Elaeis guineensis Jacq in Indonesia. A three factors experiment were conducted, with mycorrhizal inoculation (M0 and M1, bacterial B. subtilis B10 inoculation (B0 and B1, and G. boninense inoculation (G0 and G1 as the first, second, and third factors, respectively. The results showed that disease severity index, plant height, root dry-weight, and phosphorus uptake were affected by co-inoculation of mycorrhizal endosymbiotic bacteria B. subtilis B10 and composite of arbuscular mycorrhizal fungi. Co-inoculation of mycorrhizal endosymbiotic bacteria B. subtilis B10 and arbuscular mycorrhizal fungi did not only reduce the percentage of basal stem rot incidence, but also significantly increased plant height and phosphorus uptake by oil palm seedlings. Our results suggest that in oil palm seedlings mycorrhizal endosymbiotic bacteria B. subtilis B10 worked synergistically with arbuscular mycorrhizal fungi in increasing plant adaptation toward biotic stress of pathogen G. boninese and could be promising biocontrol agents.

  5. Ectomycorrhizal inoculation of willows on cut-over bored peatland

    Energy Technology Data Exchange (ETDEWEB)

    Loree, M.; Lumme, I.; Niemi, M.; Toermaelae, T.

    1988-05-01

    Ectomycorrhizal fungal inoculation was explored as a means to improve productivity of experimental short-rotation plantations of the willows Salix viminalis L. and Salix dasyclados Wimm. for biomass production on surface-mined peatlands in northern Finland. Both willow species formed ectomycorrhizas with Amanita spp., Cortinarius purpurascens, Entoloma nidorosum and other Entoloma spp., Hebeloma crustuliniforme, H. pusillum, Laccaria bicolor, and Paxillus involutus in greenhouse experiments. Field trials on a mined peatland site revealed (after one growing season) statistically significant growth stimultion due to inoculation, but these results were sometimes attributable to non-symbiotic effects of inoculation. Inoculation with some Entoloma isolates resulted in additional field growth stimulation due to symbiotic effects both willow species: plants inoculated with Entoloma were sometimes twice as large as control plants. however, such effects were observed only in plots receiving normal phosphate fertilization 40-80 kg as opposed to low 10-40 kg application and were not consistent from season to season.

  6. Bacterial communities in an ultrapure water containing storage tank of a power plant.

    Science.gov (United States)

    Bohus, Veronika; Kéki, Zsuzsa; Márialigeti, Károly; Baranyi, Krisztián; Patek, Gábor; Schunk, János; Tóth, Erika M

    2011-12-01

    Ultrapure waters (UPWs) containing low levels of organic and inorganic compounds provide extreme environment. On contrary to that microbes occur in such waters and form biofilms on surfaces, thus may induce corrosion processes in many industrial applications. In our study, refined saltless water (UPW) produced for the boiler of a Hungarian power plant was examined before and after storage (sampling the inlet [TKE] and outlet [TKU] waters of a storage tank) with cultivation and culture independent methods. Our results showed increased CFU and direct cell counts after the storage. Cultivation results showed the dominance of aerobic, chemoorganotrophic α-Proteobacteria in both samples. In case of TKU sample, a more complex bacterial community structure could be detected. The applied molecular method (T-RFLP) indicated the presence of a complex microbial community structure with changes in the taxon composition: while in the inlet water sample (TKE) α-Proteobacteria (Sphingomonas sp., Novosphingobium hassiacum) dominated, in the outlet water sample (TKU) the bacterial community shifted towards the dominance of α-Proteobacteria (Rhodoferax sp., Polynucleobacter sp., Sterolibacter sp.), CFB (Bacteroidetes, formerly Cytophaga-Flavobacterium-Bacteroides group) and Firmicutes. This shift to the direction of fermentative communities suggests that storage could help the development of communities with an increased tendency toward corrosion. PMID:22207294

  7. Inoculação do feijoeiro com Rhizobium tropici associada à exsudato de Mimosa flocculosa com diferentes doses de nitrogênio Rhizobium tropici associated with Mimosa flocculosa exudates inoculation effect on bean plants under different nitrogen rates

    Directory of Open Access Journals (Sweden)

    Eulene Francisco da Silva

    2009-01-01

    , strains CIAT 899 and PRF 81, and the association of Rhizobium with the exudates of the Mimosa flocculosa seeds. The sub-subparcels received of four doses of nitrogen fertilization applied on covering: 0, 40, 80 and 120 kg ha-1 N. The inoculation of Rhizobium associated with the addition of exudates of Mimosa flocculosa seeds resulted in higher shoot dry weight. Besides that, the nitrogen fertilization, on the tested doses, reduced, in a linear way, the nodulation of the bean plant. It was also verified that corn as a preceding crop for bean has contributed to the increase of the weight of 100 grains, while the addition of combined N did not contribute to the improvement on the number of beans per plant, neither of the grain yield of bean plants, independent of the dose that was used.

  8. Extreme promiscuity of a bacterial and a plant diterpene synthase enables combinatorial biosynthesis.

    Science.gov (United States)

    Jia, Meirong; Potter, Kevin C; Peters, Reuben J

    2016-09-01

    Diterpenes are widely distributed across many biological kingdoms, where they serve a diverse range of physiological functions, and some have significant industrial utility. Their biosynthesis involves class I diterpene synthases (DTSs), whose activity can be preceded by that of class II diterpene cyclases (DTCs). Here, a modular metabolic engineering system was used to examine the promiscuity of DTSs. Strikingly, both a bacterial and plant DTS were found to exhibit extreme promiscuity, reacting with all available precursors with orthogonal activity, producing an olefin or hydroxyl group, respectively. Such DTS promiscuity enables combinatorial biosynthesis, with remarkably high yields for these unoptimized non-native enzymatic combinations (up to 15mg/L). Indeed, it was possible to readily characterize the 13 unknown products. Notably, 16 of the observed diterpenes were previously inaccessible, and these results provide biosynthetic routes that are further expected to enable assembly of more extended pathways to produce additionally elaborated 'non-natural' diterpenoids. PMID:27060773

  9. Isolation of bacterial fish pathogen Aeromonas hydrophila and therapeutic effects of medicinal plants on its invasion

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    Md. Tareq-Uz-Zaman

    2014-04-01

    Full Text Available Aeromonas hydrophila, a bacterial pathogen, was isolated form Pangasius hypophthalmus. For pathogenicity test, different doses were injected intramuscularly in Barbonymus gonionotus. Crude extracts were prepared from various parts Azadirachta indica, Curcuma longa, C. zedoaria, and Callotropis gigentia and applied to B. gonionotus for 7 days. Bath treatment was done up to their tolerance level and well ventilation was confirmed for aeration and 50% water was exchanged daily. Minimum inhibitory dose was detected as 7 mg/ml. High inhibitory effect was observed in case of A. indica and mixed extract of A. indica and C. gigentia. Both A. indica and C. gigentia showed the best result with 90-95% recovery of infected fish at a dose of 7 mg/l. C. zedoaria showed moderate to weak effect with 50-60% recovery at the same dose. The present study showed that medicinal plants would be an effective control measure against A. hydrophila.

  10. Bacterial community variation and microbial mechanism of triclosan (TCS) removal by constructed wetlands with different types of plants.

    Science.gov (United States)

    Zhao, Congcong; Xie, HuiJun; Xu, Jingtao; Xu, Xiaoli; Zhang, Jian; Hu, Zhen; Liu, Cui; Liang, Shuang; Wang, Qian; Wang, Jingmin

    2015-02-01

    Triclosan (TCS) is a broad-spectrum synthetic antimicrobial agent that is toxic to microbes and other aquatic organisms. Constructed wetlands (CWs) are now popular in TCS removal. However, knowledge on the effects of TCS on the bacterial community and microbial removal mechanism in CWs is lacking. The effects of TCS (60 μg L(-1)) on bacterial communities in batch-loaded CWs with emergent (Typha angustifolia), submerged (Hydrilla verticillata), and floating plant (Salvinia natans) were analyzed by 454 pyrosequencing technology. After six periods of experiment, the TCS removal efficiencies were over 90% in CWs, and negative effects of TCS on bacterial community richness and diversity were observed. Moreover, plant species effect existed. Bacterial strains that contributed to TCS biodegradation in CWs were successfully identified. In TCS-treated T. angustifolia and H. verticillata CWs, beta-Proteobacteria increased by 16.63% and 18.20%, respectively. In TCS-treated S. natans CWs, delta- and gamma-Proteobacteria and Sphingobacteria increased by 9.36%, 19.49%, and 31.37%, respectively, and could relate to TCS biodegradation. TCS affected the development of certain bacteria, and eventually, the bacterial community structures in CWs. This research provided ecologically relevant information on bacterial community and microbial removal mechanism in CWs under TCS treatment. PMID:25461066

  11. Interspecific variation of the bacterial community structure in the phyllosphere of the three major plant components of mangrove forests

    Science.gov (United States)

    Dias, Armando Cavalcante Franco; Taketani, Rodrigo Gouveia; Andreote, Fernando Dini; Luvizotto, Danice Mazzer; da Silva, João Luis; Nascimento, Rosely dos Santos; de Melo, Itamar Soares

    2012-01-01

    Mangrove forests encompass a group of trees species that inhabit the intertidal zones, where soil is characterized by the high salinity and low availability of oxygen. The phyllosphere of these trees represent the habitat provided on the aboveground parts of plants, supporting in a global scale, a large and complex microbial community. The structure of phyllosphere communities reflects immigration, survival and growth of microbial colonizers, which is influenced by numerous environmental factors in addition to leaf physical and chemical properties. Here, a combination of culture-base methods with PCR-DGGE was applied to test whether local or plant specific factors shape the bacterial community of the phyllosphere from three plant species (Avicenia shaueriana, Laguncularia racemosa and Rhizophora mangle), found in two mangroves. The number of bacteria in the phyllosphere of these plants varied between 3.62 x 104 in A. schaeriana and 6.26 x 103 in R. mangle. The results obtained by PCR-DGGE and isolation approaches were congruent and demonstrated that each plant species harbor specific bacterial communities in their leaves surfaces. Moreover, the ordination of environmental factors (mangrove and plant species), by redundancy analysis (RDA), also indicated that the selection exerted by plant species is higher than mangrove location on bacterial communities at phyllosphere. PMID:24031877

  12. Mercuric ion reduction and resistance in transgenic Arabidopsis thaliana plants expressing a modified bacterial merA gene.

    OpenAIRE

    Rugh, C L; Wilde, H D; Stack, N M; Thompson, D. M.; Summers, A O; Meagher, R B

    1996-01-01

    With global heavy metal contamination increasing, plants that can process heavy metals might provide efficient and ecologically sound approaches to sequestration and removal. Mercuric ion reductase, MerA, converts toxic Hg2+ to the less toxic, relatively inert metallic mercury (Hg0) The bacterial merA sequence is rich in CpG dinucleotides and has a highly skewed codon usage, both of which are particularly unfavorable to efficient expression in plants. We constructed a mutagenized merA sequenc...

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

    OpenAIRE

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

    2013-01-01

    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 rh...

  14. Evaluation of antibacterial activity of crude protein extracts from seeds of six different medical plants against standard bacterial strains

    OpenAIRE

    Al Akeel, Raid; Al-Sheikh, Yazeed; Mateen, Ayesha; Syed, Rabbani; Janardhan, K.; V C Gupta

    2013-01-01

    A huge group of natural antimicrobial compounds are active against a large spectrum of bacterial strains causing infectious threat. The present study was conducted to investigate the crude extracts of antimicrobial protein and peptide efficacy from six medicinal plant seeds. Extraction was carried out in Sodium phosphate citrate buffer, and Sodium acetate buffer using different pH. Antimicrobial activities of these plants were determined by the microbiological technique using Agar well diffus...

  15. Bulk and Rhizosphere Soil Bacterial Communities Studied by Denaturing Gradient Gel Electrophoresis: Plant-Dependent Enrichment and Seasonal Shifts Revealed

    OpenAIRE

    Smalla, K.; Wieland, G.; Buchner, A.; A. Zock; Parzy, J.; Kaiser, S; Roskot, N.; Heuer, H.; Berg, G

    2001-01-01

    The bacterial rhizosphere communities of three host plants of the pathogenic fungus Verticillium dahliae, field-grown strawberry (Fragaria ananassa Duch.), oilseed rape (Brassica napus L.), and potato (Solanum tuberosum L.), were analyzed. We aimed to determine the degree to which the rhizosphere effect is plant dependent and whether this effect would be increased by growing the same crops in two consecutive years. Rhizosphere or soil samples were taken five times over the vegetation periods....

  16. INFLUENCE OF ELEMENTAL SULFUR AND/OR INOCULATION WITH SULFUR OXIDIZING BACTERIA ON GROWTH, AND NUTRIENT CONTENT OF SORGHUM PLANTS GROWN ON DIFFERENT SOILS

    OpenAIRE

    Hala Kandil; M. H. El-Halfawi; Ibrahim, S. A.

    2011-01-01

    A pot experiment was conducted to study the effect of elemental sulfur(E.S) rates (300 and 600 ppm) and/or sulfur oxidizing bacteria (S.O.B. ATCC 8158) on growth and nutrients content of sorghum plants grown on different soils (sandy soils(I & II) and clay loam soil).The obtained results could be summarized in the followings:Sorghum plants:Significant increases over the control were observed in fresh and dry weights of sorghum plant as well as its content of SO4=, N, P, K, Fe, Mn, Zn and Cu b...

  17. Stress inoculation modeled in mice

    OpenAIRE

    Brockhurst, J; Cheleuitte-Nieves, C; Buckmaster, C L; Schatzberg, A. F.; Lyons, D M

    2015-01-01

    Stress inoculation entails intermittent exposure to mildly stressful situations that present opportunities to learn, practice and improve coping in the context of exposure psychotherapies and resiliency training. Here we investigate behavioral and hormonal aspects of stress inoculation modeled in mice. Mice randomized to stress inoculation or a control treatment condition were assessed for corticosterone stress hormone responses and behavior during open-field, object-exploration and tail-susp...

  18. Emergence of Competitive Dominant Ammonia-Oxidizing Bacterial Populations in a Full-Scale Industrial Wastewater Treatment Plant

    OpenAIRE

    Layton, Alice C.; Dionisi, Hebe; Kuo, H.-W.; Robinson, Kevin G.; Garrett, Victoria M.; Meyers, Arthur; Sayler, Gary S.

    2005-01-01

    Ammonia-oxidizing bacterial populations in an industrial wastewater treatment plant were investigated with amoA and 16S rRNA gene real-time PCR assays. Nitrosomonas nitrosa initially dominated, but over time RI-27-type ammonia oxidizers, also within the Nitrosomonas communis lineage, increased from below detection to codominance. This shift occurred even though nitrification remained constant.

  19. A family of conserved bacterial effectors inhibits salicylic acid-mediated basal immunity and promotes disease necrosis in plants.

    Science.gov (United States)

    DebRoy, Sruti; Thilmony, Roger; Kwack, Yong-Bum; Nomura, Kinya; He, Sheng Yang

    2004-06-29

    Salicylic acid (SA)-mediated host immunity plays a central role in combating microbial pathogens in plants. Inactivation of SA-mediated immunity, therefore, would be a critical step in the evolution of a successful plant pathogen. It is known that mutations in conserved effector loci (CEL) in the plant pathogens Pseudomonas syringae (the Delta CEL mutation), Erwinia amylovora (the dspA/E mutation), and Pantoea stewartii subsp. stewartii (the wtsE mutation) exert particularly strong negative effects on bacterial virulence in their host plants by unknown mechanisms. We found that the loss of virulence in Delta CEL and dspA/E mutants was linked to their inability to suppress cell wall-based defenses and to cause normal disease necrosis in Arabidopsis and apple host plants. The Delta CEL mutant activated SA-dependent callose deposition in wild-type Arabidopsis but failed to elicit high levels of callose-associated defense in Arabidopsis plants blocked in SA accumulation or synthesis. This mutant also multiplied more aggressively in SA-deficient plants than in wild-type plants. The hopPtoM and avrE genes in the CEL of P. syringae were found to encode suppressors of this SA-dependent basal defense. The widespread conservation of the HopPtoM and AvrE families of effectors in various bacteria suggests that suppression of SA-dependent basal immunity and promotion of host cell death are important virulence strategies for bacterial infection of plants. PMID:15210989

  20. Role of bacterial biofertilizers in agriculture and forestry

    Directory of Open Access Journals (Sweden)

    Paula García-Fraile

    2015-08-01

    Full Text Available Many rhizospheric bacterial strains possess plant growth-promoting mechanisms. These bacteria can be applied as biofertilizers in agriculture and forestry, enhancing crop yields. Bacterial biofertilizers can improve plant growth through several different mechanisms: (i the synthesis of plant nutrients or phytohormones, which can be absorbed by plants, (ii the mobilization of soil compounds, making them available for the plant to be used as nutrients, (iii the protection of plants under stressful conditions, thereby counteracting the negative impacts of stress, or (iv defense against plant pathogens, reducing plant diseases or death. Several plant growth-promoting rhizobacteria (PGPR have been used worldwide for many years as biofertilizers, contributing to increasing crop yields and soil fertility and hence having the potential to contribute to more sustainable agriculture and forestry. The technologies for the production and application of bacterial inocula are under constant development and improvement and the bacterial-based biofertilizer market is growing steadily. Nevertheless, the production and application of these products is heterogeneous among the different countries in the world. This review summarizes the main bacterial mechanisms for improving crop yields, reviews the existing technologies for the manufacture and application of beneficial bacteria in the field, and recapitulates the status of the microbe-based inoculants in World Markets.

  1. Investigating the Antimicrobial Bioactivity of Cyano bacterial Extracts on Some Plant and Human Pathogens

    International Nuclear Information System (INIS)

    The search for broad spectrum antimicrobial agents against microbial pathogens, as the available bioactive compounds, has decreasing efficacy and the multidrug resistance trait is spreading among pathogens. Accordingly, the study was carried out to investigate the antimicrobial bioactivity of extracts derived from a cyano bacterial strain from Egypt. The solvents used were diethyl ether, chloroform and methanol. The antimicrobial bioassay of the lipophilic fraction dissolved in diethyl ether of Synechococcus spp. (isolated from Wadi El-Natroun, Egypt) showed the highest broad spectrum bioactivity as it inhibited the growth of both plant and human pathogens. The extract was also effective on the filamentous plant pathogenic fungi Aspergillus flavus and Aspergillus niger. The effects of incubation periods, growth media and pH values on both growth and antimicrobial activity of Synechococcus spp. were investigated. Chu medium was the medium that gave the highest growth followed by BG11 medium then Oscillatoria medium and all these three media showed antibacterial activities but only BG11 showed both antibacterial and antifungal activities after 18 days of incubation. The pH value 10 proved to be the best for growth and antimicrobial activities of Synechococcus spp. in BG11 medium

  2. Automatic Generation Control Using PI Controller with Bacterial Foraging for both Thermal and Hydro Plants

    Directory of Open Access Journals (Sweden)

    Preeti Hooda,

    2014-06-01

    Full Text Available The load-frequency control (LFC is used to restore the balance between load and generation in each control area by means of speed control. In power system, the main goal of load frequency control (LFC or automatic generation control (AGC is to maintain the frequency of each area and tie- line power flow within specified tolerance by adjusting the MW outputs of LFC generators so as to accommodate fluctuating load demands. In this paper, attempt is made to make a scheme for automatic generation control within a restructured environment considering effects of contracts between DISCOs and GENCOs to make power system network in normal state where, GENCO used are hydro plants as well as thermal plants. The bacterial foraging optimization technique is being developed, which is applied to AGC in an interconnected four area system.The performance of the system is obtained by MATLAB Simulink tool. The results are shown in frequency and power response for four area AGC system. In this paper we have shown practical work by using thermal and hydro both system at Genco’s side.As reheated system transfer function is being used.

  3. Effectiveness of Endophytic Bacterial Consortium of Coffee Plant on Mortality of Pratylenchus Coffeae in Vitro

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    dwi halimah

    2015-12-01

    Full Text Available Bacteria live in wild in form of a consortium. Use of microbial consortium tends to give better results than single isolate, because the action of enzyme of each type of microbe can complement each other in order to survive. This study aimed to study the effectiveness of bacterial endophytic consortium from coffee plant on plant growth and mortality of parasitic nematodes in coffee. Isolation of bacteria is conducted  by growing the crushed roots, stems and leaves of coffee on 20% TSA media, then testing their hemolysis and hypersensitivity reaction. Selected isolates were tested on their effect on the growth of seedling and Pratylenchus coffeae mortality, as well as their chitinolytic, proteolytic, lipolytic, HCN production, dissolution of phosphate (P and fixation of nitrogen (N2 abilities. The results showed that from 27 isolates of the consortium, 23 isolates showed negative reaction to hypersensitive test and 9 isolates to hemolysis test. The highest mortality rate was shown by K6 isolate (65.8%. The highest growth was shown by K15 and K 21 isolates while the highest root length by K21 isolate. Further analisys showed that 100% of the isolates could hydrolyze proteases, lipid, and produce HCN, while chitinolytic activity was shown by 78% isolates which could fix N2 and 11% of isolates could dissolve phosphate.

  4. Multiplex sequencing of bacterial artificial chromosomes for assembling complex plant genomes.

    Science.gov (United States)

    Beier, Sebastian; Himmelbach, Axel; Schmutzer, Thomas; Felder, Marius; Taudien, Stefan; Mayer, Klaus F X; Platzer, Matthias; Stein, Nils; Scholz, Uwe; Mascher, Martin

    2016-07-01

    Hierarchical shotgun sequencing remains the method of choice for assembling high-quality reference sequences of complex plant genomes. The efficient exploitation of current high-throughput technologies and powerful computational facilities for large-insert clone sequencing necessitates the sequencing and assembly of a large number of clones in parallel. We developed a multiplexed pipeline for shotgun sequencing and assembling individual bacterial artificial chromosomes (BACs) using the Illumina sequencing platform. We illustrate our approach by sequencing 668 barley BACs (Hordeum vulgare L.) in a single Illumina HiSeq 2000 lane. Using a newly designed parallelized computational pipeline, we obtained sequence assemblies of individual BACs that consist, on average, of eight sequence scaffolds and represent >98% of the genomic inserts. Our BAC assemblies are clearly superior to a whole-genome shotgun assembly regarding contiguity, completeness and the representation of the gene space. Our methods may be employed to rapidly obtain high-quality assemblies of a large number of clones to assemble map-based reference sequences of plant and animal species with complex genomes by sequencing along a minimum tiling path. PMID:26801048

  5. Plant growth promotion induced by phosphate solubilizing endophytic Pseudomonas isolates

    OpenAIRE

    Oteino, Nicholas; Lally, Richard D.; Kiwanuka, Samuel; Lloyd, Andrew; Ryan, David; Germaine, Kieran J.; Dowling, David N.

    2015-01-01

    The use of plant growth promoting bacterial inoculants as live microbial biofertilizers provides a promising alternative to chemical fertilizers and pesticides. Inorganic phosphate solubilization is one of the major mechanisms of plant growth promotion by plant associated bacteria. This involves bacteria releasing organic acids into the soil which solubilize the phosphate complexes converting them into ortho-phosphate which is available for plant up-take and utilization. The study presented h...

  6. Effect of post-inoculation relative humidity (RH) on peanut infection by Sclerotinia sclerotiorum

    Science.gov (United States)

    Stems of six-week-old plants of the cv Okrun (susceptible to Sclerotinia blight) were inoculated with S. sclerotiorum, isolated from pumpkin. Two post-inoculation humidity regimes of 100% RH were used. In the first RH regime, one inoculation chamber was kept open for the duration of experiment (DO...

  7. Engineering an enhanced, thermostable, monomeric bacterial luciferase gene as a reporter in plant protoplasts.

    Directory of Open Access Journals (Sweden)

    Boyu Cui

    Full Text Available The application of the luxCDABE operon of the bioluminescent bacterium Photorhabdus luminescens as a reporter has been published for bacteria, yeast and mammalian cells. We report here the optimization of fused luxAB (the bacterial luciferase heterodimeric enzyme expression, quantum yield and its application as a reporter gene in plant protoplasts. The fused luxAB gene was mutated by error prone PCR or chemical mutagenesis and screened for enhanced luciferase activity utilizing decanal as substrate. Positive luxAB mutants with superior quantum yield were subsequently shuffled by DNase I digestion and PCR assembly for generation of recombinants with additional increases in luciferase activity in bacteria. The coding sequence of the best recombinant, called eluxAB, was then optimized further to conform to Arabidopsis (Arabidopsis thaliana codon usage. A plant expression vector of the final, optimized eluxAB gene (opt-eluxAB was constructed and transformed into protoplasts of Arabidopsis and maize (Zea mays. Luciferase activity was dramatically increased for opt-eluxAB compared to the original luxAB in Arabidopsis and maize cells. The opt-eluxAB driven by two copies of the 35S promoter expresses significantly higher than that driven by a single copy. These results indicate that the eluxAB gene can be used as a reporter in plant protoplasts. To our knowledge, this is the first report to engineer the bacterium Photorhabdus luminescens luciferase luxAB as a reporter by directed evolution which paved the way for further improving the luxAB reporter in the future.

  8. Aminomethylenediphosphonate: A Potent Type-Specific Inhibitor of Both Plant and Phototrophic Bacterial H+-Pyrophosphatases.

    Science.gov (United States)

    Zhen, R. G.; Baykov, A. A.; Bakuleva, N. P.; Rea, P. A.

    1994-01-01

    The suitability of different pyrophosphate (PPi) analogs as inhibitors of the vacuolar H+-translocating inorganic pyrophosphatase (V-PPase; EC 3.6.1.1) of tonoplast vesicles isolated from etiolated hypocotyls of Vigna radiata was investigated. Five 1,1-diphosphonates and imidodiphosphate were tested for their effects on substrate hydrolysis by the V-PPase at a substrate concentration corresponding to the Km of the enzyme. The order of inhibitory potency (apparent inhibition constants, Kiapp values, [mu]M, in parentheses) of the compounds examined was aminomethylenediphosphonate (1.8) > hydroxymethylenediphosphonate (5.7) [almost equal to] ethane-1-hydroxy-1,1-diphosphonate (6.5) > imidodiphosphate (12) > methylenediphosphonate (68) > dichloromethylenediphosphonate (>500). The specificity of three of these compounds, aminomethylenediphosphonate, imidodiphosphate, and methylenediphosphonate, was determined by comparing their effects on the V-PPase and vacuolar H+-ATPase from Vigna, plasma membrane H+-ATPase from Beta vulgaris, H+-PPi synthase of chromatophores prepared from Rhodospirillum rubrum, soluble PPase from Saccharomyces cerevisiae, alkaline phosphatase from bovine intestinal mucosa, and nonspecific monophosphoesterase from Vigna at a PPi concentration equivalent to 10 times the Km of the V-PPase. Although all three PPi analogs inhibited the plant V-PPase and bacterial H+-PPi synthase with qualitatively similar kinetics, whether substrate hydrolysis or PPi-dependent H+-translocation was measured, neither the vacuolar H+-ATPase nor plasma membrane H+-ATPase nor any of the non-V-PPase-related PPi hydrolases were markedly inhibited under these conditions. It is concluded that 1, 1-diphosphonates, in general, and aminomethylenediphosphonate, in particular, are potent type-specific inhibitors of the V-PPase and its putative bacterial homolog, the H+-PPi synthase of Rhodospirillum. PMID:12232069

  9. Metabolic Coevolution in the Bacterial Symbiosis of Whiteflies and Related Plant Sap-Feeding Insects.

    Science.gov (United States)

    Luan, Jun-Bo; Chen, Wenbo; Hasegawa, Daniel K; Simmons, Alvin M; Wintermantel, William M; Ling, Kai-Shu; Fei, Zhangjun; Liu, Shu-Sheng; Douglas, Angela E

    2015-09-01

    Genomic decay is a common feature of intracellular bacteria that have entered into symbiosis with plant sap-feeding insects. This study of the whitefly Bemisia tabaci and two bacteria (Portiera aleyrodidarum and Hamiltonella defensa) cohoused in each host cell investigated whether the decay of Portiera metabolism genes is complemented by host and Hamiltonella genes, and compared the metabolic traits of the whitefly symbiosis with other sap-feeding insects (aphids, psyllids, and mealybugs). Parallel genomic and transcriptomic analysis revealed that the host genome contributes multiple metabolic reactions that complement or duplicate Portiera function, and that Hamiltonella may contribute multiple cofactors and one essential amino acid, lysine. Homologs of the Bemisia metabolism genes of insect origin have also been implicated in essential amino acid synthesis in other sap-feeding insect hosts, indicative of parallel coevolution of shared metabolic pathways across multiple symbioses. Further metabolism genes coded in the Bemisia genome are of bacterial origin, but phylogenetically distinct from Portiera, Hamiltonella and horizontally transferred genes identified in other sap-feeding insects. Overall, 75% of the metabolism genes of bacterial origin are functionally unique to one symbiosis, indicating that the evolutionary history of metabolic integration in these symbioses is strongly contingent on the pattern of horizontally acquired genes. Our analysis, further, shows that bacteria with genomic decay enable host acquisition of complex metabolic pathways by multiple independent horizontal gene transfers from exogenous bacteria. Specifically, each horizontally acquired gene can function with other genes in the pathway coded by the symbiont, while facilitating the decay of the symbiont gene coding the same reaction. PMID:26377567

  10. Composição química e estabilidade aeróbia em silagens de milho preparadas com inoculantes bacteriano e/ou enzimático - DOI: 10.4025/actascianimsci.v28i2.640 Chemical composition and aerobic stability of corn silages made with bacterials and/or enzymatic inoculants - DOI: 10.4025/actascianimsci.v28i2.640

    Directory of Open Access Journals (Sweden)

    Elzânia Sales Pereira

    2006-01-01

    Full Text Available Este trabalho avaliou o efeito de inoculantes bacterianos e/ou enzimáticos na composição química e na estabilidade aeróbia da silagem de milho confeccionada em minisilos. Os tratamentos foram: SC (silagem controle, SIB (silagem com inoculante bacteriano, SIBE (silagem com inoculante bacteriano e enzimático e SIE (silagem com inoculante enzimático. A adição de inoculante não alterou os teores de matéria orgânica (87,43%, proteína bruta (7,99%, fibra em detergente neutro (55,43% e fibra em detergente ácido (27,67%. Os tratamentos SIE e SC apresentaram, na abertura, o menor (3,28 e maior (3,42 pH, e, após o período de exposição ao ar, o menor (3,87 e maior (6,64 pH, respectivamente. O uso de inoculantes não influenciou os teores de N-amoniacal das silagens. Os tratamentos com inoculantes apresentaram menor pico de temperatura, maior tempo para atingir o pico de temperatura e maior estabilidade aeróbia.This work evaluated the effect of bacterial and/or enzymatic inoculants on chemical composition and aerobic stability in corn silage, made in mini-silos. The treatments were: CS (control silage, SBI (silage with bacterial inoculant, SBEI (silage with bacterial and enzymatic inoculant and SEI (silage with enzymatic inoculant. The use of inoculants did not affect the organic matter (87,43%, crude protein (7,99%, neutral detergent fiber (55,43% and acid detergent fiber (27,67% contents. The SEI and CS treatments showed the lowest (3,28 and the highest (3,42 pH values in the beginning and after an air exposure period, showed again the lowest (3,87 and the highest (6,64 pH values, respectively. The inoculants used did not affect N-amonniacal contents of the silages. The treatments with inoculants presented the lowest temperature peak, more time to reach this temperature and the highest aerobics stability.

  11. Multiplication and Viability of some Rhizobium Strains to be used as Inoculants for Agricultural Biomass Production

    Directory of Open Access Journals (Sweden)

    Simina Neo

    2012-05-01

    Full Text Available Rhizobia are well known for their capacity to establish a symbiosis with legumes. They inhabit root nodules, where they reduce atmospheric nitrogen and make it available to the plant. Biological nitrogen fixation is an important component of sustainable agriculture, and rhizobial inoculants have been applied frequently as biofertilizers. In this review we approach the subject of legumes inoculation in order to improve the nitrogen fixing capacity. In the first part of the experiment, the Rhizobium strains were cultivated on media indicated in the literature as optimal for bacterial growing and development in laboratory conditions. Afterwards, the Rhizobium strains that have grown and accumulate biomass were tested in different conditions of pH and salinity. The biomass accumulation was determinate by spectrophotometer. The obtained values shown that the Rhizobium strains tested can be used to inoculate the legumes cultivated on acid, basic and alkaline soils. Finally, the stability in real time of two strains of Rhizobium (Rhizobium meliloti and Rhizobium japonicum mixed with different supports was evaluated during a 6- months period. The supports studied were: peat, peat and calcium carbonate, zeolite, and ceramic. The highest number of viable cells at the end of the experiment was obtained in ceramic with Rhizobium japonicum (8x105 cells/gram, and the lowest number of viable cells was obtained in zeolite with Rhizobium meliloti (1,1x103 cells/gram.

  12. A Model to Explain Plant Growth Promotion Traits: A Multivariate Analysis of 2,211 Bacterial Isolates

    Science.gov (United States)

    da Costa, Pedro Beschoren; Granada, Camille E.; Ambrosini, Adriana; Moreira, Fernanda; de Souza, Rocheli; dos Passos, João Frederico M.; Arruda, Letícia; Passaglia, Luciane M. P.

    2014-01-01

    Plant growth-promoting bacteria can greatly assist sustainable farming by improving plant health and biomass while reducing fertilizer use. The plant-microorganism-environment interaction is an open and complex system, and despite the active research in the area, patterns in root ecology are elusive. Here, we simultaneously analyzed the plant growth-promoting bacteria datasets from seven independent studies that shared a methodology for bioprospection and phenotype screening. The soil richness of the isolate's origin was classified by a Principal Component Analysis. A Categorical Principal Component Analysis was used to classify the soil richness according to isolate's indolic compound production, siderophores production and phosphate solubilization abilities, and bacterial genera composition. Multiple patterns and relationships were found and verified with nonparametric hypothesis testing. Including niche colonization in the analysis, we proposed a model to explain the expression of bacterial plant growth-promoting traits according to the soil nutritional status. Our model shows that plants favor interaction with growth hormone producers under rich nutrient conditions but favor nutrient solubilizers under poor conditions. We also performed several comparisons among the different genera, highlighting interesting ecological interactions and limitations. Our model could be used to direct plant growth-promoting bacteria bioprospection and metagenomic sampling. PMID:25542031

  13. A model to explain plant growth promotion traits: a multivariate analysis of 2,211 bacterial isolates.

    Directory of Open Access Journals (Sweden)

    Pedro Beschoren da Costa

    Full Text Available Plant growth-promoting bacteria can greatly assist sustainable farming by improving plant health and biomass while reducing fertilizer use. The plant-microorganism-environment interaction is an open and complex system, and despite the active research in the area, patterns in root ecology are elusive. Here, we simultaneously analyzed the plant growth-promoting bacteria datasets from seven independent studies that shared a methodology for bioprospection and phenotype screening. The soil richness of the isolate's origin was classified by a Principal Component Analysis. A Categorical Principal Component Analysis was used to classify the soil richness according to isolate's indolic compound production, siderophores production and phosphate solubilization abilities, and bacterial genera composition. Multiple patterns and relationships were found and verified with nonparametric hypothesis testing. Including niche colonization in the analysis, we proposed a model to explain the expression of bacterial plant growth-promoting traits according to the soil nutritional status. Our model shows that plants favor interaction with growth hormone producers under rich nutrient conditions but favor nutrient solubilizers under poor conditions. We also performed several comparisons among the different genera, highlighting interesting ecological interactions and limitations. Our model could be used to direct plant growth-promoting bacteria bioprospection and metagenomic sampling.

  14. Sweet pepper seed responses to inoculation with microorganisms and coating with micronutrients, aminoacids and plant growth regulators Tratamento de sementes de pimentão com microrganismos, micronutrientes, aminoácidos e reguladores de crescimento

    Directory of Open Access Journals (Sweden)

    Kênia Almeida Diniz

    2009-06-01

    Full Text Available Small sized seeds, such as the horticultural species, have limited quantities of reserves that can be balanced by coating then with essential nutrients for their initial development. In addition, inoculation of the seeds with microorganisms may protect the plants against phytopathogens, thus enhancing their growth. The present work had the objective of evaluate the physiological quality and seedling development of sweet pepper seeds and seedlings coated with several kind of films. Seeds were first coated with polymers and then with antagonistic microorganisms (Trichoderma viride, Trichoderma polysporhum, Trichoderma stromaticum, Beauveria bassiana, Metarhizium anisopliae, mycorrhizas, aminoacids, micronutrients and plant growth regulators. Evaluation was performed for percentage of germination and for seedling emergence, speed of emergence index, number of plants, dry mass of the aerial and root parts and height of the seedlings. Inoculation with Trichoderma viride increased the percentage and rate of the seedlings emergence Inoculation with Trichoderma viride, Metarhizium anisopliae and mycorrhizas promote better seedling development; seed microbiolization with microorganisms Trichoderma viride, T. polysporhum, T. stromaticum, Beauveria bassiana, Metarhizium anisopliae. Mycorrhizas mixture negatively affected seeds and seedling quality. Seed covering with plant growht regulator, at a 5 mL kg-1 dose increased the roots dry matter.Em sementes pequenas, como as de espécies hortícolas, as limitadas quantidades de reservas podem ser equilibradas por meio do seu recobrimento com nutrientes essenciais para o seu desenvolvimento inicial. Além disso, a inoculação dessas sementes com microrganismos, além de proteger as plantas contra fitopatógenos, pode promover o seu crescimento. Assim, objetivo do presente trabalho foi avaliar o efeito de tipos de revestimentos na qualidade de sementes e mudas de pimentão (Capsicum annum. Para tanto, as

  15. Nucleic Acid-Based Detection and Identification of Bacterial and Fungal Plant Pathogens - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Kingsley, Mark T.

    2001-03-13

    The threat to American interests from terrorists is not limited to attacks against humans. Terrorists might seek to inflict damage to the U.S. economy by attacking our agricultural sector. Infection of commodity crops by bacterial or fungal crop pathogens could adversely impact U.S. agriculture, either directly from damage to crops or indirectly from damage to our ability to export crops suspected of contamination. Recognizing a terrorist attack against U.S. agriculture, to be able to prosecute the terrorists, is among the responsibilities of the members of Hazardous Material Response Unit (HMRU) of the Federal Bureau of Investigation (FBI). Nucleic acid analysis of plant pathogen strains by the use of polymerase chain reaction (PCR) amplification techniques is a powerful method for determining the exact identity of pathogens, as well as their possible region of origin. This type of analysis, however, requires that PCR assays be developed specific to each particular pathogen strain, and analysis protocols developed that are specific to the particular instrument used for detection. The objectives of the work described here were threefold: 1) to assess the potential terrorist threat to U.S. agricultural crops, 2) to determine whether suitable assays exist to monitor that threat, and 3) where assays are needed for priority plant pathogen threats, to modify or develop those assays for use by specialists at the HMRU. The assessment of potential threat to U.S. commodity crops and the availability of assays for those threats were described in detail in the Technical Requirements Document (9) and will be summarized in this report. This report addresses development of specific assays identified in the Technical Requirements Document, and offers recommendations for future development to ensure that HMRU specialists will be prepared with the PCR assays they need to protect against the threat of economic terrorism.

  16. Parameters that enhance the bacterial expression of active plant polyphenol oxidases.

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    Mareike E Dirks-Hofmeister

    Full Text Available Polyphenol oxidases (PPOs, EC 1.10.3.1 are type-3 copper proteins that enzymatically convert diphenolic compounds into their corresponding quinones. Although there is significant interest in these enzymes because of their role in food deterioration, the lack of a suitable expression system for the production of soluble and active plant PPOs has prevented detailed investigations of their structure and activity. Recently we developed a bacterial expression system that was sufficient for the production of PPO isoenzymes from dandelion (Taraxacum officinale. The system comprised the Escherichia coli Rosetta 2 (DE3 [pLysSRARE2] strain combined with the pET-22b(+-vector cultivated in auto-induction medium at a constant low temperature (26 °C. Here we describe important parameters that enhance the production of active PPOs using dandelion PPO-2 for proof of concept. Low-temperature cultivation was essential for optimal yields, and the provision of CuCl2 in the growth medium was necessary to produce an active enzyme. By increasing the copper concentration in the production medium to 0.2 mM, the yield in terms of PPO activity per mol purified protein was improved 2.7-fold achieving a v(max of 0.48 ± 0.1 µkat per mg purified PPO-2 for 4-methylcatechol used as a substrate. This is likely to reflect the replacement of an inactive apo-form of the enzyme with a correctly-folded, copper-containing counterpart. We demonstrated the transferability of the method by successfully expressing a PPO from tomato (Solanum lycopersicum showing that our optimized system is suitable for the analysis of further plant PPOs. Our new system therefore provides greater opportunities for the future of research into this economically-important class of enzymes.

  17. Influence of Inoculation on Soybean Adaptivity to Ultraviolet Irradiation

    International Nuclear Information System (INIS)

    Effect of inoculation on soybean (Glycine hispida, Max., var. ''Adreula'') adaptivity to ultraviolet radiation (UV) has been investigated in preflowering and flowering phases. For this purpose photosynthetic activity of leaves, respiration, dry matter accumulation content of plastid pigments, protein and starch were studied. Plants were inoculated by Rhizobium before the sowing and irradiated with high, middle and low intensities of full spectrum UV radiation during the whole vegetation. The obtained experimental results have shown, that UV radiation induced different changes among the studied indices of inoculated and uninoculated variants of soybean, making possible to say that, inoculated plants possess more potential abilities of adaptation to the changing conditions of UV radiation. (author)

  18. Responses of Ammonia-Oxidising Bacterial Communities to Nitrogen, Lime, and Plant Species in Upland Grassland Soil

    Directory of Open Access Journals (Sweden)

    Deirdre C. Rooney

    2010-01-01

    Full Text Available Agricultural improvement of seminatural grasslands has been shown to result in changes to plant and microbial diversity, with consequences for ecosystem functioning. A microcosm approach was used to elucidate the effects of two key components of agricultural improvement (nitrogen addition and liming on ammonia-oxidising bacterial (AOB communities in an upland grassland soil. Plant species characteristic of unimproved and improved pastures (A. capillaris and L. perenne were planted in microcosms, and lime, nitrogen (NH4NO3, or lime plus nitrogen added. The AOB community was profiled using terminal restriction fragment length polymorphism (TRFLP of the amoA gene. AOB community structure was largely altered by NH4NO3 addition, rather than liming, although interactions between nitrogen addition and plant species were also evident. Results indicate that nitrogen addition drives shifts in the structure of key microbial communities in upland grassland soils, and that plant species may play a significant role in determining AOB community structure.

  19. Responses of Ammonia-Oxidising Bacterial Communities to Nitrogen, Lime, and Plant Species in Upland Grassland Soil

    International Nuclear Information System (INIS)

    Agricultural improvement of semi natural grasslands has been shown to result in changes to plant and microbial diversity, with consequences for ecosystem functioning. A microcosm approach was used to elucidate the effects of two key components of agricultural improvement (nitrogen addition and liming) on ammonia-oxidising bacterial (AOB) communities in an upland grassland soil. Plant species characteristic of unimproved and improved pastures (A. capillaries and L. perenne) were planted in microcosms, and lime, nitrogen (NH4NO3), or lime plus nitrogen added. The AOB community was profiled using terminal restriction fragment length polymorphism (TRFLP) of the amoA gene. AOB community structure was largely altered by NH4NO3 addition, rather than liming, although interactions between nitrogen addition and plant species were also evident. Results indicate that nitrogen addition drives shifts in the structure of key microbial communities in upland grassland soils, and that plant species may play a significant role in determining AOB community structure

  20. Changes of microbial activities and soil aggregation in rhizosphere soil of lettuce plants by drought and the possible influence of inoculation with AM fungi and/or PGPR

    Science.gov (United States)

    Kohler, J.; Caravaca, F.; Roldán, A.

    2009-04-01

    The effect of different arbuscular mycorrhizal (AM) fungi, Glomus intraradices (Schenk & Smith) or Glomus mosseae (Nicol & Gerd.) Gerd. & Trappe, and plant growth-promoting rhizobacteria (PGPR) (Pseudomonas mendocina Palleroni), alone or in combination, on structural stability and microbial activity in the rhizosphere soil of Lactuca sativa L. was assessed under well-watered conditions and two levels of drought. Desiccation caused an increase in aggregate stability and water-soluble and total carbohydrates but there were no significant differences among treated soils and the control soil. The glomalin-related soil protein (GRSP) levels in both the activities than the control soil, independent of the water regime.

  1. Inoculation of phosphate solubilizing bacteria for the improvement of lead accumulation by Brassica juncea.

    Science.gov (United States)

    Ren, Y X; Zhu, X L; Fan, D D; Ma, P; Liang, L H

    2013-01-01

    Two phosphate-solubilizing bacterial strains were isolated and identified as Acinetobacter calcoaceticus YC-5a and Enterobacter agglomerans KMC-7 based on the 16S rRNA gene sequence analysis. A. calcoaceticus YC-5a is less well known as a phosphate-solubilizing plant-associated bacterium. The plant growth-promoting properties of the phosphate-solubilizing bacteria (PSB) were characterized in vitro, including their phosphate-solubilizing activities and their capabilities for producing indole-3-acetic acid and siderophores. A pot experiment was conducted to elucidate the effects of inoculating both strains on the growth and Pb uptake of Brassica juncea grown in different concentrations of Pb-contaminated soils. Inoculation with both PSB not only stimulated the growth of B. juncea, but it also influenced the accumulation of Pb in the shoots and roots of the host plant. The present study demonstrates that PSB are a valuable microbial resource that can be exploited to improve the efficiency of phytoextraction. PMID:23530360

  2. Application of non-linear models to predict inhibition effects of various plant hydrosols on Listeria monocytogenes inoculated on fresh-cut apples.

    Science.gov (United States)

    Ozturk, Ismet; Tornuk, Fatih; Sagdic, Osman; Kisi, Ozgur

    2012-07-01

    In this study, we studied the effects of some plant hydrosols obtained from bay leaf, black cumin, rosemary, sage, and thyme in reducing Listeria monocytogenes on the surface of fresh-cut apple cubes. Adaptive neuro-fuzzy inference system (ANFIS), artificial neural network (ANN), and multiple linear regression (MLR) models were used for describing the behavior of L. monocytogenes against the hydrosol treatments. Approximately 1-1.5 log CFU/g decreases in L. monocytogenes counts were observed after individual hydrosol treatments for 20 min. By extending the treatment time to 60 min, thyme, sage, or rosemary hydrosols eliminated L. monocytogenes, whereas black cumin and bay leaf hydrosols did not lead to additional reductions. In addition to antibacterial measurements, the abilities of ANFIS, ANN, and MLR models were compared with respect to estimation of the survival of L. monocytogenes. The root mean square error, mean absolute error, and determination coefficient statistics were used as comparison criteria. The comparison results indicated that the ANFIS model performed the best for estimating the effects of the plant hydrosols on L. monocytogenes counts. The ANN model was also effective; the MLR model was found to be poor at estimating L. monocytogenes numbers. PMID:22690764

  3. Isolation and Purification of Bacterial Strains from Treatment Plants for Effective and Efficient Bioconversion of Domestic Wastewater Sludge

    Directory of Open Access Journals (Sweden)

    K. C.A. Jalal

    2006-01-01

    Full Text Available Forty six bacterial strains were isolated from nine different sources in four treatment plants namely Indah Water Konsortium (IWK sewage treatment plant, International Islamic University Malaysia (IIUM treatment plant-1,-2 and –3 to evaluate the bioconversion process in terms of efficient biodegradation and bioseparation. The bacterial strains isolated were found to be 52.2% (24 isolates and 47.8% (22 isolates in the IWK and IIUM treatment plants respectively. The results showed that the higher microbial population (9-10x104 cfu mLˉ1 was observed in the secondary clarifier of IWK treatment plant. Only the gram-staining identification was done in the strains isolated from IWK treatment plant not to be determined from IIUM. Among the isolates from IWK, 10 isolates of gram-positive bacillus (GPB and gram-positive cocci (GPC, 10 isolates of gram-negative bacillus (GNB and rest were both or undetermined. Gram-negative cocci (GNC were not found in the isolates from IWK.

  4. Evaluation of Phytase Producing Bacteria for Their Plant Growth Promoting Activities

    OpenAIRE

    Prashant Singh; Vinod Kumar; Sanjeev Agrawal

    2014-01-01

    Bacterial inoculants are known to possess plant growth promoting abilities and have potential as liquid biofertilizer application. Four phytase producing bacterial isolates (phytase activity in the range of 0.076–0.174 U/mL), identified as Advenella species (PB-05, PB-06, and PB-10) and Cellulosimicrobium sp. PB-09, were analyzed for their plant growth promoting activities like siderophore production, IAA production, HCN production, ammonia production, phosphate solubilization, and antifungal...

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

    Science.gov (United States)

    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. PMID:26331482

  6. Interactions of Seedborne Bacterial Pathogens with Host and Non-Host Plants in Relation to Seed Infestation and Seedling Transmission

    OpenAIRE

    Bhabesh Dutta; Ronald Gitaitis; Samuel Smith; David Langston

    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...

  7. Inoculation in Political Campaign Communication.

    Science.gov (United States)

    Pfau, Michael; Burgoon, Michael

    1988-01-01

    Posits a strategy of resistance to the influence of attack messages in political campaigns. Finds that political campaign messages can be designed to inoculate supporters of candidates against subsequent attack messages of opposing candidates. (MS)

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

    Science.gov (United States)

    De La Torre-Ruiz, Neyser; Ruiz-Valdiviezo, Víctor Manuel; Rincón-Molina, Clara Ivette; Rodríguez-Mendiola, Martha; Arias-Castro, Carlos; Gutiérrez-Miceli, Federico Antonio; Palomeque-Dominguez, Héctor; Rincón-Rosales, Reiner

    2016-01-01

    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 (pagave plants with proper biological characteristics for agroindustrial and biotechnological use and to increase the sugar content in this agave species. PMID:27268113

  9. Soil inoculation steers restoration of terrestrial ecosystems.

    Science.gov (United States)

    Wubs, E R Jasper; van der Putten, Wim H; Bosch, Machiel; Bezemer, T Martijn

    2016-01-01

    Many natural ecosystems have been degraded because of human activities(1,2) and need to be restored so that biodiversity is protected. However, restoration can take decades and restoration activities are often unsuccessful(3) because of abiotic constraints (for example, eutrophication, acidification) and unfavourable biotic conditions (for example, competition or adverse soil community composition). A key question is what manageable factors prevent transition from degraded to restored ecosystems and what interventions are required for successful restoration(2,4). Experiments have shown that the soil community is an important driver of plant community development(5-8), suggesting that manipulation of the soil community is key to successful restoration of terrestrial ecosystems(3,9). Here we examine a large-scale, six-year-old field experiment on ex-arable land and show that application of soil inocula not only promotes ecosystem restoration, but that different origins of soil inocula can steer the plant community development towards different target communities, varying from grassland to heathland vegetation. The impact of soil inoculation on plant and soil community composition was most pronounced when the topsoil layer was removed, whereas effects were less strong, but still significant, when the soil inocula were introduced into intact topsoil. Therefore, soil inoculation is a powerful tool to both restore disturbed terrestrial ecosystems and steer plant community development. PMID:27398907

  10. In vitro evaluation of Pseudomonas bacterial isolates from rice phylloplane for biocontrol of Rhizoctonia solani and plant growth promoting traits.

    Science.gov (United States)

    Akter, Shamima; Kadir, Jugah; Juraimi, Abdul Shukor; Saud, Halimi Mohd

    2016-07-01

    The ability for biocontrol and plant growth promotion of three Pseudomonas bacterial isolates namely Pseudomonas fluorescens (UMB20), Pseudomonas aeruginosa (KMB25) and Pseudomonas asplenii (BMB42) obtained from rice plants was investigated. Fungal growth inhibition by the isolates ranged from 86.85 to 93.15% in volatile and 100% in diffusible metabolites test. Among the isolates, BMB42 showed fungal growth inhibition significantly in the volatile metabolite test. Isolates UMB20 and BMB42 were able to synthesis chitinase with chitinolytic indices of 13.66 and 13.50, respectively. In case of -1,3-glucanase, all the isolates showed activity to produce this enzyme at varied levels and isolate KMB25 showed significantly highest activity (53.53 ppm). Among the three isolates, KMB25 showed positive response to protease production and all of them were negative to pectinase and lipase and positive to the production of siderophore, and HCN, and were able to solubilize tricalcium phosphate. All the three bacterial isolates were capable of forming biofilm at different levels. Above results suggest that phylloplane Pseudomonas bacterial isolates have potential for antifungal activities and plant growth promotion. PMID:27498507

  11. Characterization of epiphytic bacterial communities from grapes, leaves, bark and soil of grapevine plants grown, and their relations.

    Directory of Open Access Journals (Sweden)

    Guilherme Martins

    Full Text Available Despite its importance in plant health and crop quality, the diversity of epiphytic bacteria on grape berries and other plant parts, like leaves and bark, remains poorly described, as does the role of telluric bacteria in plant colonization. In this study, we compare the bacterial community size and structure in vineyard soils, as well as on grapevine bark, leaves and berries. Analyses of culturable bacteria revealed differences in the size and structure of the populations in each ecosystem. The highest bacteria population counts and the greatest diversity of genera were found in soil samples, followed by bark, grapes and leaves. The identification of isolates revealed that some genera - Pseudomonas, Curtobacterium, and Bacillus - were present in all ecosystems, but in different amounts, while others were ecosystem-specific. About 50% of the genera were common to soil and bark, but absent from leaves and grapes. The opposite was also observed: grape and leaf samples presented 50% of genera in common that were absent from trunk and soil. The bacterial community structure analyzed by T-RFLP indicated similarities between the profiles of leaves and grapes, on the one hand, and bark and soil, on the other, reflecting the number of shared T-RFs. The results suggest an interaction between telluric bacterial communities and the epiphytic bacteria present on the different grapevine parts.

  12. Iron Deficiency Induced by Chrysobactin in Saintpaulia Leaves Inoculated with Erwinia chrysanthemi.

    Science.gov (United States)

    Neema, C.; Laulhere, J. P.; Expert, D.

    1993-07-01

    In this communication, we examine the fate of iron during soft rot pathogenesis caused by Erwinia chrysanthemi on its host, Saintpaulia ionantha. The spread of soft rot caused by this enterobacterium was previously shown to depend on a functional genetic locus encoding a high-affinity iron assimilation system involving the catechol-type siderophore chrysobactin. Leaf intercellular fluid from healthy plants was analyzed with regard to the iron content and its availability for bacterial growth. It was compared to the fluid from diseased plants for the presence of strong iron ligands, using a new approach based on the iron-binding property of an ion-exchange resin. Further characterization allowed the identification of chrysobactin in diseased tissues, thus providing the first evidence for the external release of a microbial siderophore during pathogenesis. Competition for nutritional iron was also studied through a plant-bacterial cell system: iron incorporated into plant ferritin appeared to be considerably reduced in bacteria-treated suspension soybean cells. The same effect was visualized during treatment of soybean cells with axenic leaf intercellular fluid from E. chrysanthemi-inoculated saintpaulia leaves or with chrysobactin. PMID:12231882

  13. Exopolysaccharide-Producing Plant Growth-Promoting Rhizobacteria Under Salinity Condition

    Institute of Scientific and Technical Information of China (English)

    S. K. UPADHYAY; J. S. SINGH; D. P. SINGH

    2011-01-01

    Salt-tolerant plant growth-promoting rhizobacteria (PGPR) can play an important role in alleviating soil salinity stress during plant growth and bacterial exopolysaccharide (EPS) can also help to mitigate salinity stress by reducing the content of Na+ available for plant uptake. In this study, native bacterial strains of wheat rhizosphere in soils of Varanasi, India, were screened to identify the EPS-producing salt-tolerant rhizobacteria with plant growth-promoting traits. The various rhizobacteria strains were isolated and identified using 16S rDNA sequencing. The plant growth-promoting effect of inoculation of seedlings with these bacterial strains was evaluated under soil salinity conditions in a pot experiment. Eleven bacterial strains which initially showed tolerance up to 80 g L-1 NaCl also exhibited an EPS-producing potential. The results suggested that the isolated bacterial strains demonstrated some of the plant growth-promoting traits such as phosphate solubilizing ability and production of auxin, proline, reducing sugars, and total soluble sugars, Furthermore, the inoculated wheat plants had an increased biomass compared to the un-inoculated plants.

  14. Rosmarinic acid is a homoserine lactone mimic produced by plants that activates a bacterial quorum-sensing regulator.

    Science.gov (United States)

    Corral-Lugo, Andrés; Daddaoua, Abdelali; Ortega, Alvaro; Espinosa-Urgel, Manuel; Krell, Tino

    2016-01-01

    Quorum sensing is a bacterial communication mechanism that controls genes, enabling bacteria to live as communities, such as biofilms. Homoserine lactone (HSL) molecules function as quorum-sensing signals for Gram-negative bacteria. Plants also produce previously unidentified compounds that affect quorum sensing. We identified rosmarinic acid as a plant-derived compound that functioned as an HSL mimic. In vitro assays showed that rosmarinic acid bound to the quorum-sensing regulator RhlR of Pseudomonas aeruginosa PAO1 and competed with the bacterial ligand N-butanoyl-homoserine lactone (C4-HSL). Furthermore, rosmarinic acid stimulated a greater increase in RhlR-mediated transcription in vitro than that of C4-HSL. In P. aeruginosa, rosmarinic acid induced quorum sensing-dependent gene expression and increased biofilm formation and the production of the virulence factors pyocyanin and elastase. Because P. aeruginosa PAO1 infection induces rosmarinic acid secretion from plant roots, our results indicate that rosmarinic acid secretion is a plant defense mechanism to stimulate a premature quorum-sensing response. P. aeruginosa is a ubiquitous pathogen that infects plants and animals; therefore, identification of rosmarinic acid as an inducer of premature quorum-sensing responses may be useful in agriculture and inform human therapeutic strategies. PMID:26732761

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

    International Nuclear Information System (INIS)

    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 (N2), 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 (N2) 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 storage

  16. Bacterial and plant HAD enzymes catalyse a missing phosphatase step in thiamin diphosphate biosynthesis.

    Science.gov (United States)

    Hasnain, Ghulam; Roje, Sanja; Sa, Na; Zallot, Rémi; Ziemak, Michael J; de Crécy-Lagard, Valérie; Gregory, Jesse F; Hanson, Andrew D

    2016-01-15

    The penultimate step of thiamin diphosphate (ThDP) synthesis in plants and many bacteria is dephosphorylation of thiamin monophosphate (ThMP). Non-specific phosphatases have been thought to mediate this step and no genes encoding specific ThMP phosphatases (ThMPases) are known. Comparative genomic analysis uncovered bacterial haloacid dehalogenase (HAD) phosphatase family genes (from subfamilies IA and IB) that cluster on the chromosome with, or are fused to, thiamin synthesis genes and are thus candidates for the missing phosphatase (ThMPase). Three typical candidates (from Anaerotruncus colihominis, Dorea longicatena and Syntrophomonas wolfei) were shown to have efficient in vivo ThMPase activity by expressing them in an Escherichia coli strain engineered to require an active ThMPase for growth. In vitro assays confirmed that these candidates all preferred ThMP to any of 45 other phosphate ester substrates tested. An Arabidopsis thaliana ThMPase homologue (At4g29530) of unknown function whose expression pattern and compartmentation fit with a role in ThDP synthesis was shown to have in vivo ThMPase activity in E. coli and to prefer ThMP to any other substrate tested. However, insertional inactivation of the At4g29530 gene did not affect growth or the levels of thiamin or its phosphates, indicating that Arabidopsis has at least one other ThMPase gene. The Zea mays orthologue of At4g29530 (GRMZM2G035134) was also shown to have ThMPase activity. These data identify HAD genes specifying the elusive ThMPase activity, indicate that ThMPases are substrate-specific rather than general phosphatases and suggest that different evolutionary lineages have recruited ThMPases independently from different branches of the HAD family. PMID:26537753

  17. Mycorrhizal inoculation affects the phytochemical content in strawberry fruits

    Directory of Open Access Journals (Sweden)

    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.

  18. Tagging RAPD markers to a bacterial blight resistance gene in rice

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@The somaclonal mutant HX_3 has shown a broad spectrum resistance to bacterial blight. To study the inheritance of the bacterial blight resistance in HX_3, a cross was made between HX_3 and a susceptible cultivar Longtefu A. The F2 population of 418 plants was inoculated with Chinese bacterial blight strain Zhe 173 (pathotype Ⅳ ). Results showed that the F2 progenies segregated in a ratio of 3R∶ 1S (324 resistant plants and 94 susceptible plants). From the plants tested, 114 individuals (86 resistant and 28 susceptible) were chosen randomly for RAPD analysis. Twelve highly resistant and 12 highly susceptible plants were selected to form a resistant pool and a susceptible pool, respectively.

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

    Science.gov (United States)

    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. PMID:27133557

  20. Production of bacterial leaf blight resistant mulberry through tissue culture and induced mutation

    International Nuclear Information System (INIS)

    Mon Noi multiple shoots obtained from axillary buds in vitro cultures were induced mutation by irradiating with gamma rays at the optimum dose (LD 50) of 40 Gy. In vitro inoculation technique for bacterial blight disease of mulberry caused by Pseudomonas syringae p v. mori was done by leaf-rub method, using bacterial suspension at 107 cells per milliliter which was the lowest concentration to cause highest disease severity. A total of 8357 Mon Noi gamma irradiated plantlets in 7-11 generations were screened for bacterial blight disease resistance. Eighteen plants survived and free from bacterial contamination. These surviving plants were in vitro rapid multiplication then screened for disease resistance in greenhouse. At present, only 4 lines from 18 plants are selected

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Effects of chemical and biological pesticides on plant growth parameters and rhizospheric bacterial community structure in Vigna radiata

    International Nuclear Information System (INIS)

    Highlights: • Non-target effects of pesticides employing qualitative and quantitative approaches. • Qualitative shifts in resident and active bacterial community structure. • Abundance of 16S rRNA gene and transcripts were reduced significantly. • Effects of biological pesticide similar to chemical pesticides on rhizospheric bacteria. - Abstract: With increasing application of pesticides in agriculture, their non-target effects on soil microbial communities are critical to soil health maintenance. The present study aimed to evaluate the effects of chemical pesticides (chlorpyrifos and cypermethrin) and a biological pesticide (azadirachtin) on growth parameters and the rhizospheric bacterial community of Vigna radiata. Qualitative and quantitative analysis by PCR-denaturing gradient gel electrophoresis (DGGE) and q-PCR, respectively, of the 16S rRNA gene and transcript were performed to study the impact of these pesticides on the resident and active rhizospheric bacterial community. While plant parameters were not affected significantly by the pesticides, a shift in the bacterial community structure was observed with an adverse effect on the abundance of 16S rRNA gene and transcripts. Chlorpyrifos showed almost complete degradation toward the end of the experiment. These non-target impacts on soil ecosystems and the fact that the effects of the biopesticide mimic those of chemical pesticides raise serious concerns regarding their application in agriculture

  3. Effects of chemical and biological pesticides on plant growth parameters and rhizospheric bacterial community structure in Vigna radiata

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Sunil; Gupta, Rashi; Sharma, Shilpi, E-mail: shilpi@dbeb.iitd.ac.in

    2015-06-30

    Highlights: • Non-target effects of pesticides employing qualitative and quantitative approaches. • Qualitative shifts in resident and active bacterial community structure. • Abundance of 16S rRNA gene and transcripts were reduced significantly. • Effects of biological pesticide similar to chemical pesticides on rhizospheric bacteria. - Abstract: With increasing application of pesticides in agriculture, their non-target effects on soil microbial communities are critical to soil health maintenance. The present study aimed to evaluate the effects of chemical pesticides (chlorpyrifos and cypermethrin) and a biological pesticide (azadirachtin) on growth parameters and the rhizospheric bacterial community of Vigna radiata. Qualitative and quantitative analysis by PCR-denaturing gradient gel electrophoresis (DGGE) and q-PCR, respectively, of the 16S rRNA gene and transcript were performed to study the impact of these pesticides on the resident and active rhizospheric bacterial community. While plant parameters were not affected significantly by the pesticides, a shift in the bacterial community structure was observed with an adverse effect on the abundance of 16S rRNA gene and transcripts. Chlorpyrifos showed almost complete degradation toward the end of the experiment. These non-target impacts on soil ecosystems and the fact that the effects of the biopesticide mimic those of chemical pesticides raise serious concerns regarding their application in agriculture.

  4. Rhizosphere bacterial communities of dominant steppe plants shift in response to a gradient of simulated nitrogen deposition

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    An eYang

    2015-08-01

    Full Text Available We evaluated effects of 9-year simulation of simulated nitrogen (N deposition on microbial composition and diversity in the rhizosphere of two dominant temperate grassland species: grass Stipa krylovii and forb Artemisia frigida. Microbiomes in S. krylovii and A.frigida rhizosphere differed, but changed consistently along the N gradient. These changes were correlated to N-induced shifts to plant community. Hence, as plant biomass changed, so did bacterial rhizosphere communities, a result consistent with the role that N fertilizer has been shown to play in altering plant-microbial mutualisms. A total of 23 bacterial phyla were detected in the two rhizospheric soils by pyrosequencing, with Proteobacteria, Acidobacteria and Bacteroidetes dominating the sequences of all samples. Bacterioidetes and Proteobacteria tended to increase, while Acidobacteria declined with increase in N addition rates. TM7 increased >5-fold in the high N addition rates, especially in S. krylovii rhizosphere. Nitrogen addition also decreased diversity of OTUs (operational taxonomic units, Shannon and Chao1 indices of rhizospheric microbes regardless of plant species. These results suggest that there were both similar but also specific changes in microbial communities of temperate steppes due to N deposition.

  5. Structural and functional diversity of soil bacterial and fungal communities following woody plant encroachment in the southern Great Plains

    Energy Technology Data Exchange (ETDEWEB)

    Hollister, Emily B [ORNL; Schadt, Christopher Warren [ORNL; Palumbo, Anthony Vito [ORNL; Ansley, R J [Texas A& M University; Boutton, Thomas W [Texas A& M University

    2010-01-01

    In the southern Great Plains (USA), encroachment of grassland ecosystems by Prosopis glandulosa (honey mesquite) is widespread. Mesquite encroachment alters net primary productivity, enhances stores of C and N in plants and soil, and leads to increased levels of soil microbial biomass and activity. While mesquite's impact on the biogeochemistry of the region is well established, it effects on soil microbial diversity and function are unknown. In this study, soils associated with four plant types (C{sub 3} perennial grasses, C{sub 4} midgrasses, C{sub 4} shortgrasses, and mesquite) from a mesquite-encroached mixed grass prairie were surveyed to in an attempt to characterize the structure, diversity, and functional capacity of their soil microbial communities. rRNA gene cloning and sequencing were used in conjunction with the GeoChip functional gene array to evaluate these potential differences. Mesquite soil supported increased bacterial and fungal diversity and harbored a distinct fungal community relative to other plant types. Despite differences in composition and diversity, few significant differences were detected with respect to the potential functional capacity of the soil microbial communities. These results may suggest that a high level of functional redundancy exists within the bacterial portion of the soil communities; however, given the bias of the GeoChip toward bacterial functional genes, potential functional differences among soil fungi could not be addressed. The results of this study illustrate the linkages shared between above- and belowground communities and demonstrate that soil microbial communities, and in particular soil fungi, may be altered by the process of woody plant encroachment.

  6. Bulk and rhizosphere soil bacterial communities studied by denaturing gradient gel electrophoresis: plant-dependent enrichment and seasonal shifts revealed.

    Science.gov (United States)

    Smalla, K; Wieland, G; Buchner, A; Zock, A; Parzy, J; Kaiser, S; Roskot, N; Heuer, H; Berg, G

    2001-10-01

    The bacterial rhizosphere communities of three host plants of the pathogenic fungus Verticillium dahliae, field-grown strawberry (Fragaria ananassa Duch.), oilseed rape (Brassica napus L.), and potato (Solanum tuberosum L.), were analyzed. We aimed to determine the degree to which the rhizosphere effect is plant dependent and whether this effect would be increased by growing the same crops in two consecutive years. Rhizosphere or soil samples were taken five times over the vegetation periods. To allow a cultivation-independent analysis, total community DNA was extracted from the microbial pellet recovered from root or soil samples. 16S rDNA fragments amplified by PCR from soil or rhizosphere bacterium DNA were analyzed by denaturing gradient gel electrophoresis (DGGE). The DGGE fingerprints showed plant-dependent shifts in the relative abundance of bacterial populations in the rhizosphere which became more pronounced in the second year. DGGE patterns of oilseed rape and potato rhizosphere communities were more similar to each other than to the strawberry patterns. In both years seasonal shifts in the abundance and composition of the bacterial rhizosphere populations were observed. Independent of the plant species, the patterns of the first sampling times for both years were characterized by the absence of some of the bands which became dominant at the following sampling times. Bacillus megaterium and Arthrobacter sp. were found as predominant populations in bulk soils. Sequencing of dominant bands excised from the rhizosphere patterns revealed that 6 out of 10 bands resembled gram-positive bacteria. Nocardia populations were identified as strawberry-specific bands. PMID:11571180

  7. Effects Due to Rhizospheric Soil Application of an Antagonistic Bacterial Endophyte on Native Bacterial Community and Its Survival in Soil: A Case Study with Pseudomonas aeruginosa from Banana.

    Science.gov (United States)

    Thomas, Pious; Sekhar, Aparna C

    2016-01-01

    Effective translation of research findings from laboratory to agricultural fields is essential for the success of biocontrol or growth promotion trials employing beneficial microorganisms. The rhizosphere is to be viewed holistically as a dynamic ecological niche comprising of diverse microorganisms including competitors and noxious antagonists to the bio-inoculant. This study was undertaken to assess the effects due to the soil application of an endophytic bacterium with multiple pathogen antagonistic potential on native bacterial community and its sustenance in agricultural soil. Pseudomonas aeruginosa was employed as a model system considering its frequent isolation as an endophyte, wide antagonistic effects reported against different phytopathogens and soil pests, and that the species is a known human pathogen which makes its usage in agriculture precarious. Employing the strain 'GNS.13.2a' from banana, its survival in field soil and the effects upon soil inoculation were investigated by monitoring total culturable bacterial fraction as the representative indicator of soil microbial community. Serial dilution plating of uninoculated control versus P. aeruginosa inoculated soil from banana rhizosphere indicated a significant reduction in native bacterial cfu soon after inoculation compared with control soil as assessed on cetrimide- nalidixic acid selective medium against nutrient agar. Sampling on day-4 showed a significant reduction in P. aeruginosa cfu in inoculated soil and a continuous dip thereafter registering >99% reduction within 1 week while the native bacterial population resurged with cfu restoration on par with control. This was validated in contained trials with banana plants. Conversely, P. aeruginosa showed static cfu or proliferation in axenic-soil. Lateral introduction of soil microbiome in P. aeruginosa established soil under axenic conditions or its co-incubation with soil microbiota in suspension indicated significant adverse effects by

  8. Coinoculação rizóbio e Bacillus subtilis em feijão-caupi e leucena: efeito sobre a nodulação, a fixação de N2 e o crescimento das plantas Co-inoculation rhizobia and Bacilus subtilis in cowpea and Leucaena: effects on nodulation, N2 fixation and plant growth

    Directory of Open Access Journals (Sweden)

    Ademir Sérgio Ferreira de Araújo

    2010-02-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito da associação entre o rizóbio e o Bacillus subtilis sobre a nodulação, a fixação de N2 e o crescimento do feijão-caupi (Vigna unguiculata e da leucena (Leucaena leucocephala cultivados em um Latossolo vermelho. Os tratamentos consistiram de: a testemunha; b fertilização com NPK; c inoculação com rizóbio + PK; e d inoculação com rizóbio + Bacillus subtilis + PK. Houve um aumento na nodulação do feijão-caupi com a coinoculação. A massa da parte aérea seca, o acúmulo de N e a leitura da clorofila em feijão-caupi foram maiores nos tratamentos fertilizados (NPK e no tratamento coinoculado. No caso da leucena, não houve diferenças entre os tratamentos NPK, inoculado e coinoculado. As massas das raízes secas do feijão-caupi e leucena aumentaram com a coinoculação. A coinoculação rizóbio e Bacillus subtilis favoreceu o aumento na nodulação em feijão-caupi e tem potencial para aumentar a fixação biológica do N2 e o crescimento das plantas.This research aimed to evaluate co-inoculation of Bradyrhizobium and Bacillus subtilis on nodulation, N2 fixation and growth of cowpea (Vigna unguiculata and leucaena (Leucaena leucocephala grown in a red Oxisol. Treatments consisted by: a control; b NPK; c inoculation with Bradyrhizobium + PK; d co-inoculation Bradyrhizobium + Bacillus subtilis + PK. There was an increase in nodulation of cowpea with co-inoculation. The shoot dry weight, N accumulation and chlorophyll were higher in both co-inoculated and fertilized (NPK treatments. For leucaena, there were not differences between NPK, inoculated and co-inoculated treatments. The dry weight roots of cowpea and leucaena increased with co-inoculation. The co-inoculation Bradyrhizobium and Bacillus subtilis favored the increase in nodulation of cowpea and it has potential to increase biological N2 fixation and plant growth.

  9. Disease interactions in a shared host plant: effects of pre-existing viral infection on cucurbit plant defense responses and resistance to bacterial wilt disease.

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    Lori R Shapiro

    Full Text Available Both biotic and abiotic stressors can elicit broad-spectrum plant resistance against subsequent pathogen challenges. However, we currently have little understanding of how such effects influence broader aspects of disease ecology and epidemiology in natural environments where plants interact with multiple antagonists simultaneously. In previous work, we have shown that healthy wild gourd plants (Cucurbita pepo ssp. texana contract a fatal bacterial wilt infection (caused by Erwinia tracheiphila at significantly higher rates than plants infected with Zucchini yellow mosaic virus (ZYMV. We recently reported evidence that this pattern is explained, at least in part, by reduced visitation of ZYMV-infected plants by the cucumber beetle vectors of E. tracheiphila. Here we examine whether ZYMV-infection may also directly elicit plant resistance to subsequent E. tracheiphila infection. In laboratory studies, we assayed the induction of key phytohormones (SA and JA in single and mixed infections of these pathogens, as well as in response to the feeding of A. vittatum cucumber beetles on healthy and infected plants. We also tracked the incidence and progression of wilt disease symptoms in plants with prior ZYMV infections. Our results indicate that ZYMV-infection slightly delays the progression of wilt symptoms, but does not significantly reduce E. tracheiphila infection success. This observation supports the hypothesis that reduced rates of wilt disease in ZYMV-infected plants reflect reduced visitation by beetle vectors. We also documented consistently strong SA responses to ZYMV infection, but limited responses to E. tracheiphila in the absence of ZYMV, suggesting that the latter pathogen may effectively evade or suppress plant defenses, although we observed no evidence of antagonistic cross-talk between SA and JA signaling pathways. We did, however, document effects of E. tracheiphila on induced responses to herbivory that may influence host-plant

  10. In vitro inhibitory potentials of crude plant extracts on multidrug resistant bacterial species from infected human wounds

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    Yetunde A Ekanola

    2013-01-01

    Full Text Available Background: Scientific data on usage of plants to promote wound healing is exclusively scare in Nigeria. AIM: The aim of this study was to determine in vitro inhibitory potentials of crude extracts of garlic (Allium sativum and ginger (Zingiber officinale on multiple antibiotic resistant bacteria isolated from deep and superficial human wounds. Materials and Methods: Using agar disc- and modified agar well-diffusion methods, 87 wound-borne bacterial strains, Staphylococcus aureus, Proteus mirabilis and Pseudomonas aeruginosa were screened for in vitro susceptibility to 15 commonly-available antibiotic discs, 18 antibiotic drugs and three plant extracts. Results: Staph. aureus strains exhibited 52.5-97.4% resistance to antibiotic (discs, with multiple antibiotic resistance (MAR of 25.0 -100%. Between 39.1 and 95.7% of Proteus mirabilis strains resisted the antibiotics (discs, while MAR was 37.5-100%. Resistance rates displayed by Ps. aeruginosa strains were 61.5-100% with MAR of 50.0-100%. Overall antibiotic resistance patterns of respective bacterial species recorded for the antibiotic drugs were Staph. aureus (11.1-83.3%, Pr. mirabilis (16.7-77.8% and Ps. aeruginosa (16.7-50.0% and the most-resisted antibiotic drugs were axacef (55.3-82.6%, septrin (84.2-92.3%, primpex (78.3-84.6%, mediphenicol (63.2-73.1% and augmentin 1 (43.2-76.9%. All the multidrug resistant wound-borne bacterial strains exhibited minimal to moderate susceptibility towards crude extracts of garlic (17.4-34.6% and ginger (57.7-60.8%. Conclusion: Human wound-borne bacterial strains, which were multi-resistant to commonly available antibiotics (discs/drugs were minimally or moderately susceptible to crude extracts of garlic (Allium sativum and ginger (Zingiber officinale, which can be of clinical importance as herbal therapy in wound dressings or other forms of wound treatments.

  11. Construction of a bacterial artificial chromosome library from the spikemoss Selaginella moellendorffii: a new resource for plant comparative genomics

    OpenAIRE

    Chapple Clint; Carlson John; Arumuganathan K; Mueller Christopher; Kudrna Dave; Weng Jing-Ke; Kim Hye Ran; Sisneros Nicholas; Luo Meizhong; Tanurdzic Milos; Wang Wenming; de Pamphilis Claude; Mandoli Dina; Tomkins Jeff; Wing Rod A

    2005-01-01

    Abstract Background The lycophytes are an ancient lineage of vascular plants that diverged from the seed plant lineage about 400 Myr ago. Although the lycophytes occupy an important phylogenetic position for understanding the evolution of plants and their genomes, no genomic resources exist for this group of plants. Results Here we describe the construction of a large-insert bacterial artificial chromosome (BAC) library from the lycophyte Selaginella moellendorffii. Based on cell flow cytomet...

  12. Influência do teor de matéria seca e do inoculante bacteriano nas características físicas e químicas da silagem de capim Tanzânia = Effects of dry matter content and bacterial inoculant on the physical and chemical properties and losses in Tanzânia grass silage

    Directory of Open Access Journals (Sweden)

    Solidete de Fátima Paziani

    2006-07-01

    Full Text Available Foram avaliados os efeitos do teor de matéria seca e da adição de inoculante bacteriano sobre a composição químico-bromatológica e perdas em silagens do capim Tanzânia. O uso do inoculante não foi efetivo em preservar a PB. Os índices de recuperação de matéria seca e as perdas de MS, na forma de efluente e gases, foram respectivamente de 90,6%; 53,7 kg t-1 MV e 6,4% da MS nas silagens não-emurchecidas, 93,6%; 16,8 kg t-1 MV e 5,0% com adição de milheto grão e 92,2%; 3,6 kg t-1 MV e 6,2% naquelas emurchecidas. Asdensidades de massa verde/matéria seca foram 346/105, 455/145 e 442/97 kg m-3 nas silagens emurchecidas, adicionadas com milheto e com umidade original, respectivamente. Como a elevação no teor de MS não alterou o índice de recuperação de MS, apesar de promoveralgumas modificações na composição química das silagens, a opção pelos tratamentos vai depender da ponderação de fatores que facilitem a operacionalidade e reduzam os custos na confecção da silagem.The present trial aimed to study the effect of dry matter content and the addition of bacterial inoculant on the ensilage of Tanzânia grass. The bacterial inoculant did not alter crude protein content. Dry matter recovery rates, effluent yield and DM gases losses were 90.6%, 53.7 kg t-1 wet forage, 6.4% for the wet silages; 93.6%, 16.8 kg t-1 wet forage, 5.0% for millet added silages and 92.2%, 3.6 kg t-1 wet forage, 6.2% for the wilted silages, respectively. The silages dry matter content influenced wet bulk density/dry matter silo bulk density resulting in 346/105, 455/145 and 442/97 kg m-3 for the wilted, millet added and wet silages, respectively. Because the increase on dry matter content was not offsets in DM recovery rate, although there were some changes in chemical composition, the adoption and field recommendation of strategies will be dependent on the operational and costs restrictions.

  13. Plant growth-promoting effects of native Pseudomonas strains on Mentha piperita (peppermint): an in vitro study.

    Science.gov (United States)

    Santoro, M V; Cappellari, L R; Giordano, W; Banchio, E

    2015-11-01

    Plant growth-promoting rhizobacteria (PGPR) affect growth of host plants through various direct and indirect mechanisms. Three native PGPR (Pseudomonas putida) strains isolated from rhizospheric soil of a Mentha piperita (peppermint) crop field near Córdoba, Argentina, were characterised and screened in vitro for plant growth-promoting characteristics, such as indole-3-acetic acid (IAA) production, phosphate solubilisation and siderophore production, effects of direct inoculation on plant growth parameters (shoot fresh weight, root dry weight, leaf number, node number) and accumulation and composition of essential oils. Each of the three native strains was capable of phosphate solubilisation and IAA production. Only strain SJ04 produced siderophores. Plants directly inoculated with the native PGPR strains showed increased shoot fresh weight, glandular trichome number, ramification number and root dry weight in comparison with controls. The inoculated plants had increased essential oil yield (without alteration of essential oil composition) and biosynthesis of major essential oil components. Native strains of P. putida and other PGPR have clear potential as bio-inoculants for improving productivity of aromatic crop plants. There have been no comparative studies on the role of inoculation with native strains on plant growth and secondary metabolite production (specially monoterpenes). Native bacterial isolates are generally preferable for inoculation of crop plants because they are already adapted to the environment and have a competitive advantage over non-native strains. PMID:26012535

  14. EFFECT OF DIFFERENT INOCULATION METHODS AND INOCULUM LEVELS OF MACROPHOMINA PHASEOLINA ON OKRA

    Directory of Open Access Journals (Sweden)

    Sultan A. Maitlo

    2012-12-01

    Full Text Available Among two methods of Macrophomina phaseolina inoculation used for pathogenicity test, soil infestation method comparatively checked more plant growth of okra plants than seed infestation method. Minimum plant length and weight, as well as seed germination were observed by soil infestation method. Significantly maximum plant mortality and root infection was also occurred in soil infestation method. Seed germination, plant growth, plant mortality and root infection of okra plants were adversely affected with the increasing inoculum levels of M. phaseolina. Seed germination and plant growth were negatively correlated with inoculated pathogen population; whereas, plant mortality and root infection were positively correlated with the inoculum level of M. phaseolina.

  15. Isolation of 12 Bacterial endophytes from some mangrove plants and determination of, antimicrobial properties of the isolates and the plant extracts

    Directory of Open Access Journals (Sweden)

    Ibrahim M.S Eldeen

    2014-10-01

    Full Text Available Diarrhoea is a common disease which causes pain and may be deadly, especially in developing countries. In Bangladesh, diarrhoeal diseases affect thousands of people every year, and children are especially vulnerable. Bacterial toxins or viral infections a Helle Wangensteen, Line Klarpås, Mahiuddin Alamgir, Anne B. C. Samuelsen, Karl E. Malterud diarrhoea; Bangladesh; traditional medicine; mangrove plants; Diospyros peregrina; Heritiera littoralis; Ixora coccinea; Pongamia pinnata; Rhizophora mucronata; Xylocarpus granatum; Xylocarpus moluccensis 15.00 800x600 The mangrove designates a highly productive ecosystem with important economic and environmental functions. Endophytes are microorganisms that live in the intercellular spaces of plant tissue. This study aimed to isolate and identify bacterial endophytes from five mangrove plants and to determine, antimicrobial properties of the isolates and the plant extracts against four pathogenic bacteria: Bacillus cereus, Staphylococcus aureus, Escherichia coli and Salmonella typhimurium using the deferred antagonism and the microdilution assays. Of the total 33 endophytic bacteria isolated, 18 strains showed antagonistic effects. Twelve of these inhibitors were identified using VITEK 2. Crude protein from each of the producer strains were precipitated and tested for minimum inhibitory concentration (MIC against the pathogenic bacteria using the microdilution assay. Best activities were recorded for Staphylococcus intermedius and Bacillus licheniformis (19 µl/ml against B. cereus. The S. intermedius also inhibited growth of both S. aureus and S. typhimurium (39 µl/ml. Staphylococcus lentus, Bacillus pumilus and Bacillus coagulans possessed activities against S.typhimurium with an MIC value of 78 µg/ml. For the plant extract, the lowest MIC value (9.7 µg/ml was obtained by Aviecenna lanata and Sonneratia caseolaris against B.cereus. S.caseolaris also showed significant inhibitory effects against E

  16. The bacterial population adherent to plant particles in the rumen of reindeer fed lichen, timothy hay or silage

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    Monica Alterskjær Olsen

    1998-02-01

    Full Text Available Male reindeer (Rangifer tarandus tarandus calves taken from a natural winter pasture were given ad lib. access to lichen (n = 3, timothy silage (n = 3 and hay (n = 3 for 7 weeks. Median numbers of viable anaerobic bacteria adherent to the plant particles (cells/g wet weight of rumen solids, growing on a habitat simulating medium (M8V, were significantly higher (P = 0.05 in the rumen of reindeer fed lichen (26.5 x 109- 53.0 x 109 and hay (4.0 x 109- 40.5 x 109, compared to reindeer fed silage (1.15 x 109 - 3.25 x 109. Anaerobic bacterial strains (n = 551 from the plant particles obtained from the rumen of the nine reindeer examined, were isolated using an acid swollen cellulose medium (M8SC and tested for their ability to hydrolyse carboxymethyl cellulose (CMC. The proportion of CMC hydrolysing adherent bacteria isolated from M8SC was significantly higher in reindeer fed hay (21.5% compared ro animals fed lichen (5.3% and silage (2.7% (P = 0.05. The CMC hydrolysing bacterial srrains (n=42 isolated from reindeer fed hay where characterised as non-cellulolytic Butyrivibrio fibrisolvens (9.5%, cellulolytic B. fibrisolvens (50.0%, Clostridium sp. (2.4% and unknowns (38.1%, while CMC hydrolysing strains (n=11 isolated from animals fed lichen and strains (n=4 isolated from animals fed silage where all characterised as B. fibrisolvens. None of the bacterial strains isolated from the rumen solids of reindeer fed lichen or silage were found to be cellulolytic. This study suggests that both lichen and timothy silage have a negative influence, compared to hay, on the numbers of cellulolytic bacteria adherent to the plant particles in the rumen of reindeer.

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

    Science.gov (United States)

    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

  18. A new method to provide resistance to bacterial soft rot in plants

    OpenAIRE

    Bouwmeester, K.; Govers, F.

    2014-01-01

    The invention relates to a method for providing plants, preferably potato plants, with resistance to blackleg or soft rot caused by Pectobacterium carotovorum by providing them with a gene encoding the LecRK-I.9 protein.

  19. PRODUCTION OF PLANT GROWTH PROMOTING SUBSTANCES IN BACTERIAL ISOLATES FROM THE SEAGRASS RHIZOSPHERE

    Science.gov (United States)

    Plants and rhizosphere bacteria have evolved chemical signals that enable their mutual growth. These relationships have been well investigated with agriculturally important plants, but not in seagrasses, which are important to the stability of estuaries. Seagrasses are rooted in ...

  20. Cytokinin-Induced Phenotypes in Plant-Insect Interactions: Learning from the Bacterial World

    OpenAIRE

    Giron, David; Glevarec, Gaëlle

    2014-01-01

    Recently, a renewed interest in cytokinins (CKs) has allowed the characterization of these phytohormones as key regulatory molecules in plant biotic interactions. They have been proved to be instrumental in microbe-and insect-mediated plant phenotypes that can be either beneficial or detrimental for the host-plant. In parallel, insect endosymbi-otic bacteria have emerged as key players in plant-insect interactions mediating directly or indirectly fundamental as-pects of insect nutrition, such...

  1. Dietary plant phenolic improves survival of bacterial infection in Manduca sexta caterpillars

    OpenAIRE

    del Campo, Marta L.; Halitschke, Rayko; Short, Sarah M.; Lazzaro, Brian P.; Kessler, André

    2013-01-01

    Plant phenolics are generally thought to play significant roles in plant defense against herbivores and pathogens. Many plant taxa, including Solanaceae, are rich in phenolic compounds and some insect herbivores have been shown to acquire phenolics from their hosts to use them as protection against their natural enemies. Here we demonstrate that larvae of an insect specialist on Solanaceae, the tobacco hornworm, Manduca sexta L. (Lepidoptera: Sphingidae), acquire the plant phenolic chlorogeni...

  2. Genetic diversity of bacterial communities of serpentine soil and of rhizosphere of the nickel-hyperaccumulator plant Alyssum bertolonii.

    Science.gov (United States)

    Mengoni, A; Grassi, E; Barzanti, R; Biondi, E G; Gonnelli, C; Kim, C K; Bazzicalupo, M

    2004-08-01

    Serpentine soils are characterized by high levels of heavy metals (Ni, Co, Cr), and low levels of important plant nutrients (P, Ca, N). Because of these inhospitable edaphic conditions, serpentine soils are typically home to a very specialized flora including endemic species as the nickel hyperaccumulator Alyssum bertolonii. Although much is known about the serpentine flora, few researches have investigated the bacterial communities of serpentine areas. In the present study bacterial communities were sampled at various distances from A. bertolonii roots in three different serpentine areas and their genetic diversity was assessed by terminal restriction fragment length polymorphism (T-RFLP) analysis. The obtained results indicated the occurrence of a high genetic diversity and heterogeneity of the bacterial communities present in the different serpentine areas. Moreover, TRFs (terminal restriction fragments) common to all the investigated A. bertolonii rhizosphere samples were found. A new cloning strategy was applied to 27 TRFs that were sequenced and taxonomically interpreted as mainly belonging to Gram-positive and alpha-Proteobacteria representatives. In particular, cloned TRFs which discriminated between rhizosphere and soil samples were mainly interpreted as belonging to Proteobacteria representatives. PMID:15546041

  3. Antibacterial activity of plant extracts on foodborne bacterial pathogens and food spoilage bacteria

    Science.gov (United States)

    Bacterial foodborne diseases are caused by consumption of foods contaminated with bacteria and/or their toxins. In this study, we evaluated antibacterial properties of twelve different extracts including turmeric, lemon and different kinds of teas against four major pathogenic foodborne bacteria inc...

  4. Metablic Coevolution in the bacterial symbiosis of whiteflies and related plant sap-feeding insects

    Science.gov (United States)

    In animals dependent on intracellular bacteria with very small genomes, the host cell is adapted to support the function of its bacterial symbionts, but the molecular basis of these adaptations is poorly understood. We investigated the metabolic coevolution between the whitefly Bemisia tabaci and th...

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

    Science.gov (United States)

    Hofmann, Andreas; Fischer, Doreen; Hartmann, Anton; Schmid, Michael

    2014-01-01

    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 4 × 10 CFU/ml in the axenic system or 4 × 10(5) CFU/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 some

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

    Directory of Open Access Journals (Sweden)

    AndreasHofmann

    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

  7. Simultaneous and successive inoculations of yeasts and lactic acid bacteria on the fermentation of an unsulfited Tannat grape must

    OpenAIRE

    Viviana Muñoz; Bruno Beccaria; Eduardo Abreo

    2014-01-01

    Interactions between yeasts and lactic acid bacteria are strain specific, and their outcome is expected to change in simultaneous alcoholic -malolactic fermentations from the pattern observed in successive fermentations. One Oenococcus oeni strain Lalvin VP41TM was inoculated with two Saccharomyces cerevisiae strains either simultaneously, three days after the yeast inoculation, or when alcoholic fermentation was close to finish. Early bacterial inoculations with each yeast strain allowed for...

  8. Homoserine Lactones Influence the Reaction of Plants to Rhizobia

    Directory of Open Access Journals (Sweden)

    Karl-Heinz Kogel

    2013-08-01

    Full Text Available Bacterial quorum sensing molecules not only grant the communication within bacterial communities, but also influence eukaryotic hosts. N-acyl-homoserine lactones (AHLs produced by pathogenic or beneficial bacteria were shown to induce diverse reactions in animals and plants. In plants, the reaction to AHLs depends on the length of the lipid side chain. Here we investigated the impact of two bacteria on Arabidopsis thaliana, which usually enter a close symbiosis with plants from the Fabaceae (legumes family and produce a long-chain AHL (Sinorhizobium meliloti or a short-chain AHL (Rhizobium etli. We demonstrate that, similarly to the reaction to pure AHL molecules, the impact, which the inoculation with rhizosphere bacteria has on plants, depends on the type of the produced AHL. The inoculation with oxo-C14-HSL-producing S. meliloti strains enhanced plant resistance towards pathogenic bacteria, whereas the inoculation with an AttM lactonase-expressing S. meliloti strain did not. Inoculation with the oxo-C8-HSL-producing R. etli had no impact on the resistance, which is in agreement with our previous hypothesis. In addition, plants seem to influence the availability of AHLs in the rhizosphere. Taken together, this report provides new insights in the role of N-acyl-homoserine lactones in the inter-kingdom communication at the root surface.

  9. Construction of a bacterial artificial chromosome library from the spikemoss Selaginella moellendorffii: a new resource for plant comparative genomics

    Directory of Open Access Journals (Sweden)

    Chapple Clint

    2005-06-01

    Full Text Available Abstract Background The lycophytes are an ancient lineage of vascular plants that diverged from the seed plant lineage about 400 Myr ago. Although the lycophytes occupy an important phylogenetic position for understanding the evolution of plants and their genomes, no genomic resources exist for this group of plants. Results Here we describe the construction of a large-insert bacterial artificial chromosome (BAC library from the lycophyte Selaginella moellendorffii. Based on cell flow cytometry, this species has the smallest genome size among the different lycophytes tested, including Huperzia lucidula, Diphaiastrum digita, Isoetes engelmanii and S. kraussiana. The arrayed BAC library consists of 9126 clones; the average insert size is estimated to be 122 kb. Inserts of chloroplast origin account for 2.3% of the clones. The BAC library contains an estimated ten genome-equivalents based on DNA hybridizations using five single-copy and two duplicated S. moellendorffii genes as probes. Conclusion The S. moellenforffii BAC library, the first to be constructed from a lycophyte, will be useful to the scientific community as a resource for comparative plant genomics and evolution.

  10. Bacterial Structure and Characterization of Plant Growth Promoting and Oil Degrading Bacteria from the Rhizospheres of Mangrove Plants

    NARCIS (Netherlands)

    do Carmo, Flavia Lima; dos Santos, Henrique Fragoso; Martins, Edir Ferreira; van Elsas, Jan Dirk; Rosado, Alexandre Soares; Peixoto, Raquel Silva

    2011-01-01

    Most oil from oceanic spills converges on coastal ecosystems, such as mangrove forests, which are threatened with worldwide disappearance. Particular bacteria that inhabit the rhizosphere of local plant species can stimulate plant development through various mechanisms; it would be advantageous if t

  11. Biochemical contents of pepper seedlings inoculated with phytophthora infestans and arbuscular mycorrhiza

    OpenAIRE

    Odebode A.C.; Salami A.O.

    2004-01-01

    The effect of interactions between Arbuscular Glomus etunicatum and fungus Phytophthora infestans on biochemical contents of pepper plants was investigated in a greenhouse experiment. The sugar contents (i.e. Glucose fructose and sucrose) were higher in the control and mycorrhizal inoculated pepper seedlings and the lowest in pathogen inoculated seedlings. Free amino acids were the highest in the simultaneously inoculated pepper seedlings while total phenol was found to be the highest in pepp...

  12. Antibacterial activity of plant extracts against Xanthomonas axonopodis Pv. Punicae causing bacterial blight of Pomegranate (Punica granatum L.

    Directory of Open Access Journals (Sweden)

    Alane S K

    2016-01-01

    Full Text Available Pomegranate (Punica granatum L. is the important fruit crop cultivated throughout the world. It is famous for its refreshing fruits. The crop is affected by ‘bacterial blight’ caused by Xanthomonas axonopodis pv. punicae, which is responsible for the failure of crop. It results in the dropping of leaves as well as fruits. It is very hard to manage the disease with chemicals as well as antibiotics and farmers suffer from heavy economic losses. In the present study, aqueous, ethyl alcohol and acetone extracts of ten medicinally useful plants were used against Xanthomonas axonopodis pv. punicae in vitro. The plant extracts showed antibacterial activity and caused inhibition of growth of Xanthomonas axonopodis pv. Punicae. Among them, Mentha spicata, Murraya Koeninngi, Allium sativum and Tridax procumbens caused maximum inhibition of the test bacterium.

  13. Evaluation of antibacterial activity of crude protein extracts from seeds of six different medical plants against standard bacterial strains.

    Science.gov (United States)

    Al Akeel, Raid; Al-Sheikh, Yazeed; Mateen, Ayesha; Syed, Rabbani; Janardhan, K; Gupta, V C

    2014-04-01

    A huge group of natural antimicrobial compounds are active against a large spectrum of bacterial strains causing infectious threat. The present study was conducted to investigate the crude extracts of antimicrobial protein and peptide efficacy from six medicinal plant seeds. Extraction was carried out in Sodium phosphate citrate buffer, and Sodium acetate buffer using different pH. Antimicrobial activities of these plants were determined by the microbiological technique using Agar well diffusion Assay. Extremely strong activity was observed in the seed extracts of Allium ascolinicum extracted in sodium phosphate citrate buffer at pH (5.8) against Proteus vulgaris, Escherichia coli and Staphylococcus aureus with zone of inhibition 17 mm, 17 mm and 15 mm and Rumex vesicarius at pH (7.6), Ammi majus at pH (6.8), Cichorium intybus at pH (7.4) and Cucumis sativus at pH (7.8) also showed better sensitivity against the bacterial strains with zone of inhibition ranges 16-10 mm and some of the strains were found to be resistant. Antibacterial activity pattern of different plant extracts prepared in sodium acetate buffer pH (6.5), among all the plant seed extracts used Foeniculum vulgare had shown good inhibition in all the bacterial strains used, with zone of inhibition ranges 11-12.5 mm, The extracts of C. intybus and C. sativus were found to be effective with zone of inhibition 11-6 mm and some of the strains were found to be resistant. Most of the strains found to have shown better sensitivity compared with the standard antibiotic Chloramphenicol (25 mcg). Our results showed that the plants used for our study are the richest source for antimicrobial proteins and peptides and they may be used for industrial extraction and isolation of antimicrobial compounds which may find a place in medicine industry as constituents of antibiotics. PMID:24600307

  14. Multifunctionality and diversity of culturable bacterial communities strictly associated with spores of the plant beneficial symbiont Rhizophagus intraradices.

    Science.gov (United States)

    Battini, Fabio; Cristani, Caterina; Giovannetti, Manuela; Agnolucci, Monica

    2016-02-01

    Arbuscular Mycorrhizal Fungi (AMF) live in symbiosis with most crop plants and represent essential elements of soil fertility and plant nutrition and productivity, facilitating soil mineral nutrient uptake and protecting plants from biotic and abiotic stresses. These beneficial services may be mediated by the dense and active spore-associated bacterial communities, which sustain diverse functions, such as the promotion of mycorrhizal activity, biological control of soilborne diseases, nitrogen fixation, and the supply of nutrients and growth factors. In this work, we utilised culture-dependent methods to isolate and functionally characterize the microbiota strictly associated to Rhizophagus intraradices spores, and molecularly identified the strains with best potential plant growth promoting (PGP) activities by 16S rDNA sequence analysis. We isolated in pure culture 374 bacterial strains belonging to different functional groups-actinobacteria, spore-forming, chitinolytic and N2-fixing bacteria-and screened 122 strains for their potential PGP activities. The most common PGP trait was represented by P solubilization from phytate (69.7%), followed by siderophore production (65.6%), mineral P solubilization (49.2%) and IAA production (42.6%). About 76% of actinobacteria and 65% of chitinolytic bacteria displayed multiple PGP activities. Nineteen strains with best potential PGP activities, assigned to Sinorhizobium meliloti, Streptomyces spp., Arthrobacter phenanthrenivorans, Nocardiodes albus, Bacillus sp. pumilus group, Fictibacillus barbaricus and Lysinibacillus fusiformis, showed the ability to produce IAA and siderophores and to solubilize P from mineral phosphate and phytate, representing suitable candidates as biocontrol agents, biofertilisers and bioenhancers, in the perspective of targeted management of beneficial symbionts and their associated bacteria in sustainable food production systems. PMID:26805620

  15. Screening Rice Cultivars for Resistance to Bacterial Leaf Blight.

    Science.gov (United States)

    Fred, Agaba Kayihura; Kiswara, Gilang; Yi, Gihwan; Kim, Kyung-Min

    2016-05-28

    Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most serious threats to rice production. In this study, screening of rice for resistance to BLB was carried out at two different times and locations; that is, in a greenhouse during winter and in an open field during summer. The pathogenicity of Xoo race K1 was tested on 32 Korean rice cultivars. Inoculation was conducted at the maximum tillering stage, and the lesion length was measured after 14 days of inoculation. Five cultivars, Hanareum, Namcheon, Samgdeok, Samgang, and Yangjo, were found to be resistant in both the greenhouse and open-field screenings. Expression of the plant defense-related genes JAmyb, OsNPR1, OsPR1a, OsWRKY45, and OsPR10b was observed in resistant and susceptible cultivars by qRT-PCR. Among the five genes tested, only OsPR10b showed coherent expression with the phenotypes. Screening of resistance to Xoo in rice was more accurate when conducted in open fields in the summer cultivation period than in greenhouses in winter. The expression of plant defenserelated genes after bacterial inoculation could give another perspective in elucidating defense mechanisms by using both resistant and susceptible individuals. PMID:26869604

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

    Directory of Open Access Journals (Sweden)

    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.

  17. Pectin and Xyloglucan Influence the Attachment of Salmonella enterica and Listeria monocytogenes to Bacterial Cellulose-Derived Plant Cell Wall Models.

    Science.gov (United States)

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

    2016-01-01

    Minimally processed fresh produce has been implicated as a major source of foodborne microbial pathogens globally. These pathogens must attach to the produce in order to be transmitted. Cut surfaces of produce that expose cell walls are particularly vulnerable. Little is known about the roles that different structural components (cellulose, pectin, and xyloglucan) of plant cell walls play in the attachment of foodborne bacterial pathogens. Using bacterial cellulose-derived plant cell wall models, we showed that the presence of pectin alone or xyloglucan alone affected the attachment of three Salmonella enterica strains (Salmonella enterica subsp. enterica serovar Enteritidis ATCC 13076, Salmonella enterica subsp. enterica serovar Typhimurium ATCC 14028, and Salmonella enterica subsp. indica M4) and Listeria monocytogenes ATCC 7644. In addition, we showed that this effect was modulated in the presence of both polysaccharides. Assays using pairwise combinations of S. Typhimurium ATCC 14028 and L. monocytogenes ATCC 7644 showed that bacterial attachment to all plant cell wall models was dependent on the characteristics of the individual bacterial strains and was not directly proportional to the initial concentration of the bacterial inoculum. This work showed that bacterial attachment was not determined directly by the plant cell wall model or bacterial physicochemical properties. We suggest that attachment of the Salmonella strains may be influenced by the effects of these polysaccharides on physical and structural properties of the plant cell wall model. Our findings improve the understanding of how Salmonella enterica and Listeria monocytogenes attach to plant cell walls, which may facilitate the development of better ways to prevent the attachment of these pathogens to such surfaces. PMID:26567310

  18. Effectiveness of Apu Wood Plant (Pistia stratiotes L to Reduce the Bacterial in Leachate on Integrated Waste Treatment Plant of Toisapu, Ambon

    Directory of Open Access Journals (Sweden)

    Hairudin Rasako

    2016-08-01

    Full Text Available The high population growth figures in the city of Ambon, contributed significantly impact on increasing production of waste and waste generated, both in large scale for industrial / factory, as well as domestic scale at the household level. Of the total waste and waste generated, estimated at nearly largely banished to the Final Disposal (TPA in the Integrated Waste Treatment Plant (IWTP Toisapu. One byproduct of the process is the accumulation of garbage leachate. Leachate contained in IWTP Toisapu already accommodated within a particular basin but there has been no effort or specific treatment for the reduction of pollutants contained therein. The use of water plants Wood Apu (Pistia stratiotes L can be applied as a natural control, because these plants have the ability to reduce the amount of chemical contaminants. This study was done to see how effective the water plant lettuce wood as a natural control in reducing the number of bacterial contaminants in the leachate IPST Toisapu. The research design is quasi-experimental research (quasi experiment. Samples tested were leachate originating from IPST Toisapu. The parameters measured were the levels of the numbers of E. coli, and coliform before and after the Apu wood plants.

  19. Effect of Morphology of Instantaneous Inoculant on Inoculated Result of Melted Iron

    Institute of Scientific and Technical Information of China (English)

    SHENG Da

    2003-01-01

    The characteristics of some elements in inoculant were analyzed. The effect of the morphology of instantaneous inoculant on its melting velocity was studied. When the inoculants pass through the same sieve number, the volume and the ratio of surface area to volume are different. It is evident from the theoretical analysis and experiment under some conditions that the melting velocity of inoculant depends on the morphology of inoculant. The morphology of inoculant during production should be controlled carefully.

  20. Impact of soil heat on reassembly of bacterial communities in the rhizosphere microbiome and plant disease suppression.

    Science.gov (United States)

    van der Voort, Menno; Kempenaar, Marcel; van Driel, Marc; Raaijmakers, Jos M; Mendes, Rodrigo

    2016-04-01

    The rhizosphere microbiome offers a range of ecosystem services to the plant, including nutrient acquisition and tolerance to (a)biotic stress. Here, analysing the data by Mendes et al. (2011), we show that short heat disturbances (50 or 80 °C, 1 h) of a soil suppressive to the root pathogenic fungus Rhizoctonia solani caused significant increase in alpha diversity of the rhizobacterial community and led to partial or complete loss of disease protection. A reassembly model is proposed where bacterial families that are heat tolerant and have high growth rates significantly increase in relative abundance after heat disturbance, while temperature-sensitive and slow-growing bacteria have a disadvantage. The results also pointed to a potential role of slow-growing, heat-tolerant bacterial families from Actinobacteria and Acidobacteria phyla in plant disease protection. In conclusion, short heat disturbance of soil results in rearrangement of rhizobacterial communities and this is correlated with changes in the ecosystem service disease suppression. PMID:26833547

  1. A plant natriuretic peptide-like gene in the bacterial pathogen Xanthomonas axonopodis may induce hyper-hydration in the plant host: a hypothesis of molecular mimicry

    Directory of Open Access Journals (Sweden)

    Sayed Muhammed

    2004-03-01

    Full Text Available Abstract Background Plant natriuretic peptides (PNPs are systemically mobile molecules that regulate homeostasis at nanomolar concentrations. PNPs are up-regulated under conditions of osmotic stress and PNP-dependent processes include changes in ion transport and increases of H2O uptake into protoplasts and whole tissue. Presentation of the hypothesis The bacterial citrus pathogen Xanthomonas axonopodis pv. Citri str. 306 contains a gene encoding a PNP-like protein. We hypothesise that this bacterial protein can alter plant cell homeostasis and thus is likely to represent an example of molecular mimicry that enables the pathogen to manipulate plant responses in order to bring about conditions favourable to the pathogen such as the induced plant tissue hyper-hydration seen in the wet edged lesions associated with Xanthomonas axonopodis infection. Testing the hypothesis We found a Xanthomonas axonopodis PNP-like protein that shares significant sequence similarity and identical domain organisation with PNPs. We also observed a significant excess of conserved residues between the two proteins within the domain previously identified as being sufficient to induce biological activity. Structural modelling predicts identical six stranded double-psi β barrel folds for both proteins thus supporting the hypothesis of similar modes of action. No significant similarity between the Xanthomonas axonopodis protein and other bacterial proteins from GenBank was found. Sequence similarity of the Xanthomonas axonopodis PNP-like protein with the Arabidopsis thaliana PNP (AtPNP-A, shared domain organisation and incongruent phylogeny suggest that the PNP-gene may have been acquired by the bacteria in an ancient lateral gene transfer event. Finally, activity of a recombinant Xanthomonas axonopodis protein in plant tissue and changes in symptoms induced by a Xanthomonas axonopodis mutant with a knocked-out PNP-like gene will be experimental proof of molecular mimicry

  2. Priming, induction and modulation of plant defence responses by bacterial lipopolysaccharides

    DEFF Research Database (Denmark)

    Newman, Mari-Anne; Dow, J. Maxwell; Molinaro, Antonio;

    2007-01-01

    the triggering of defence responses or to the priming of the plant to respond more rapidly and/or to a greater degree to subsequent pathogen challenge. LPS from symbiotic bacteria can have quite different effects on plants to those of pathogens. Some details are emerging of the structures within LPS...... that are responsible for induction of these different plant responses. The lipid A moiety is not solely responsible for all of the effects of LPS in plants; core oligosaccharide and O-antigen components can elicit specific responses. Here, we review the effects of LPS in induction of defence......-related responses in plants, the structures within LPS responsible for eliciting these effects and discuss the possible nature of the (as yet unidentified) LPS receptors in plants....

  3. Screening of anti-bacterial activity of medicinal plants from Belize (Central America).

    Science.gov (United States)

    Camporese, A; Balick, M J; Arvigo, R; Esposito, R G; Morsellino, N; De Simone, F; Tubaro, A

    2003-07-01

    Twenty-one extracts from seven herbal drugs, Aristolochia trilobata (Aristolochiaceae) leaves and bark, Bursera simaruba (Burseraceae) bark, Guazuma ulmifolia (Sterculiaceae) bark, Hamelia patens (Rubiaceae) leaves and Syngonium podophyllum (Araceae) leaves and bark, used in traditional medicine of Belize (Central America) as deep and superficial wound healers, were evaluated for their anti-bacterial properties. Activity was tested against standard strains of Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923 and Enterococcus faecalis ATCC 29212. Almost all the extracts were able to inhibit the growth of one or more of the bacterial strains, except that of Enterococcus faecalis. For the first time an anti-microbial activity is reported for Aristolochia trilobata as well as for Syngonium podophyllum. The hexane extracts of Aristolochia trilobata leaves and bark were the most active extracts against Staphylococcus aureus (MIC=0.31 and 0.625mg/ml, respectively). PMID:12787962

  4. Characterization of culturable bacterial endophytes and their capacity to promote plant growth from plants grown using organic or conventional practices

    OpenAIRE

    Xia, Ye; DeBolt, Seth; Dreyer, Jamin; Scott, Delia; Williams, Mark A.

    2015-01-01

    Plants have a diverse internal microbial biota that has been shown to have an important influence on a range of plant health attributes. Although these endophytes have been found to be widely occurring, few studies have correlated agricultural production practices with endophyte community structure and function. One agricultural system that focuses on preserving and enhancing soil microbial abundance and biodiversity is organic farming, and numerous studies have shown that organically managed...

  5. Plant and soil microbe interactions in controlled conditions: rhizosphere protozoa and bacterial community structure

    OpenAIRE

    Roussel-Delif, Ludovic; Aragno, Michel

    2009-01-01

    Plants influence the soil system by the large proportion of photosynthesized matters translocated to the roots and secreted into the soil. This root exudation provides an abundant energy source for rhizosphere living microorganisms. Plants are also strongly affected, positively and negatively, by the presence of soil microbiota, particularly bacteria, protozoa and fungi. Throughout the experiments conducted in this work, we aimed to better understand the influence of protozoa on plant growth....

  6. Capability of Streptomyces spp. in Controlling Bacterial Leaf Blight Disease in Rice Plants

    OpenAIRE

    Ratih D. Hastuti; Yulin Lestari2); Rasti Saraswati; Antonius Suwanto; Chaerani

    2012-01-01

    Problem statement: Bacterial Leaf Blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is the most damaging disease in lowland rice growing areas in Indonesia. Streptomyces spp. have been known as a producer of antimicrobial compounds that can be used as biocontrol agents. This study examined the ability of three promising indigenous Streptomyces isolates which were previously selected from in vitro agar media and greenhouse test to suppress natural infection of Xoo during dry and wet s...

  7. Chromium Resistant Bacteria: Impact on Plant Growth in Soil Microcosm

    Directory of Open Access Journals (Sweden)

    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.

  8. Field inoculation procedures with vesicular-arbuscular mycorrhiza

    International Nuclear Information System (INIS)

    The goal of field studies with vesicular-arbuscular mycorrhiza (VAM) is to improve crop yield by establishing vigorous VAM infections that will substantially enhance the uptake of phosphate. This objective is usually approached by introducing efficient inoculum into a field crop early enough and at a high enough rate to affect plant growth. Some consideration should also be given to ways of manipulating the native mycorrhizas because satisfactory field inoculation procedures for large-scale application are not yet well developed and the indigenous soil populations of VAM fungi are sometimes symbiotically efficient but too sparse to be effective. Thus mixed cropping systems and crop rotations that include strongly mycorrhizal plant species may well prove to be useful for building up the native VAM population. However, in this article, we are concerned primarily with the methodology of field inoculation, using VAM endophytes that have already been cultured on stock plants and tested for their symbiotic potential and soil/plant preferences

  9. Inoculation Effects of Cast Iron

    Directory of Open Access Journals (Sweden)

    E. Fraś

    2012-12-01

    Full Text Available The paper presents a solidification sequence of graphite eutectic cells of A and D types, as well as globular and cementite eutectics. The morphology of eutectic cells in cast iron, the equations for their growth and the distances between the graphite precipitations in A and D eutectic types were analyzed. It is observed a critical eutectic growth rate at which one type of eutectic transformed into another. A mathematical formula was derived that combined the maximum degree of undercooling, the cooling rate of cast iron, eutectic cell count and the eutectic growth rate. One type of eutectic structure turned smoothly into the other at a particular transition rate, transformation temperature and transformational eutectic cell count. Inoculation of cast iron increased the number of eutectic cells with flake graphite and the graphite nodule count in ductile iron, while reducing the undercooling. An increase in intensity of inoculation caused a smooth transition from a cementite eutectic structure to a mixture of cementite and D type eutectic structure, then to a mixture of D and A types of eutectics up to the presence of only the A type of eutectic structure. Moreover, the mechanism of inoculation of cast iron was studied.

  10. Rhizosphere bacterial communities associated with insect root herbivory of an invasive plant, Euphorbia esula/virgata

    Science.gov (United States)

    The invasive perennial plant of Eurasian origin, Euphorbia esula/virgata L., has been successfully controlled over large areas in North America with a synergism between larvae of Aphthona spp. and soilborne plant pathogens. However, a multitude of sites is not yet under control. Studies are needed o...

  11. Response of Andean and Mesoamerican common bean genotypes to inoculation with rhizobium strains.

    Science.gov (United States)

    In most common bean (Phaseolus vulgaris L.) production regions of Latin America, inoculants are rarely used by farmers in spite of several studies that demonstrate the importance of Rhizobium inoculation on commercial production of legume crops. This study investigated specific bean host plant-Rhizo...

  12. Impact of transgenic potatoes expressing anti-bacterial agents on bacterial endophytes is comparable with the effects of plant genotype, soil type and pathogen infection

    NARCIS (Netherlands)

    Rasche, F.; Velvis, H.; Zachow, C.; Berg, G.; Elsas, van J.D.; Sessitsch, A.

    2006-01-01

    1. Blackleg and soft rot disease of potatoes Solanum tuberosum L., mainly caused by the bacterial pathogen Erwinia carotovora ssp. atrospetica (Eca), lead to enormous yield losses world-wide. Genetically modified (GM) potatoes producing anti-bacterial agents, such as cecropin/attacin and T4 lysozyme

  13. Zoosporic plant pathogens produce bacterial autoinducer-2 that affects Vibrio harveyi quorum sensing

    Science.gov (United States)

    Kong, Ping; Lee, Bobby W.K.; Zhou, Zhaohui Sunny; Hong, Chuanxue

    2009-01-01

    The frequent co-isolation of bacteria with Phytophthora and Pythium species suggests possible interspecies communication. Zoospore free fluids (ZFF) from bacteria-free and nutrient-depleted zoospore suspensions were examined to investigate production of autoinducer-2 (AI-2), a bacterial interspecies signal molecule, by zoosporic oomycetes. ZFF from P. nicotianae, P. sojae and Py. aphanidermatum triggered luminescence of Vibrio harveyi AI-2 reporter, indicating the presence of AI-2 in zoospore extracellular products and the potential of cross-kingdom communication between oomycetes and bacteria. Production of AI-2 by zoospores was confirmed by chemical assays. These results provide new insight into the physiology and ecology of oomycetes. PMID:20002192

  14. Growth response and nutrient uptake of blue pine (Pinus wallichiana seedlings inoculated with rhizosphere microorganisms under temperate nursery conditions

    Directory of Open Access Journals (Sweden)

    M.A. Ahangar

    2012-11-01

    Full Text Available Microbial inoculants (Trichoderma harzianum, Pseudomonas fluorescens,Laccaria laccata inoculated either individually or in combinationsignificantly improved the growth and biomass of blue pine seedlings. The ECM fungus Laccaria laccata, when inoculated individually, showed significantly higher plant growth, followed by Pseudomonas fluorescens and Trichoderma harzianum. The combined inoculation of rhizosphere microorganisms showed synergistic growth promoting action and proved superior in enhancing the growth of blue pine than individual inoculation. Co-inoculation of L. laccata with P. fluorescens resulted in higher ectomycorrhizal root colonization. Uptake of nutrients (N, P, K was significantly improved by microbial inoculants, tested individually or in combination. Combined inoculation of L. laccata with T. harzianum and P. fluorescens significantly increased in N, P and K contents in blue pine seedlings as compared to control. Acid phosphatase activity in the rhizosphere of blue pine seedlings was also enhanced by these microorganisms. L. laccata exhibited higher acid phosphatase activity followed by P. fluorescens.

  15. Effect of clove oil on plant pathogenic bacteria and bacterial wilt of tomato and geranium

    Science.gov (United States)

    We determined the antibacterial activity of clove oil against seven different genera of plant pathogenic bacteria including Gram-negative Agrobacterium tumefaciens, Erwinia carotovora pv. carotovora, Pseudomonas syringae pv. syringae, Ralstonia solanacearum, and Xanthomonas campestris pv. pelargonii...

  16. Evaluation of antimicrobial activity of selected plant extracts by rapid XTT colorimetry and bacterial enumeration.

    Science.gov (United States)

    Al-Bakri, Amal G; Afifi, Fatma U

    2007-01-01

    The aim of this study was to screen and evaluate the antimicrobial activity of indigenous Jordanian plant extracts, dissolved in dimethylsulfoxide, using the rapid XTT assay and viable count methods. XTT rapid assay was used for the initial screening of antimicrobial activity for the plant extracts. Antimicrobial activity of potentially active plant extracts was further assessed using the "viable plate count" method. Four degrees of antimicrobial activity (high, moderate, weak and inactive) against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, respectively, were recorded. The plant extracts of Hypericum triquetrifolium, Ballota undulata, Ruta chalepensis, Ononis natrix, Paronychia argentea and Marrubium vulgare had shown promising antimicrobial activity. This study showed that while both XTT and viable count methods are comparable when estimating the overall antimicrobial activity of experimental substances, there is no strong linear correlation between the two methods. PMID:16831479

  17. Biochemical contents of pepper seedlings inoculated with phytophthora infestans and arbuscular mycorrhiza

    Directory of Open Access Journals (Sweden)

    Odebode A.C.

    2004-01-01

    Full Text Available The effect of interactions between Arbuscular Glomus etunicatum and fungus Phytophthora infestans on biochemical contents of pepper plants was investigated in a greenhouse experiment. The sugar contents (i.e. Glucose fructose and sucrose were higher in the control and mycorrhizal inoculated pepper seedlings and the lowest in pathogen inoculated seedlings. Free amino acids were the highest in the simultaneously inoculated pepper seedlings while total phenol was found to be the highest in pepper seedlings inoculated with P. infestans. The levels of nitrogen, phosphorus and potassium varied in the inoculated pepper seedlings without any significant difference in the treatment. The results obtained suggest protective influence of mycorrhiza by enhancing the nutritional status of the inoculated pepper seedlings.

  18. In vitro interaction of certain antimicrobial agents in combination with plant extracts against some pathogenic bacterial strains

    Institute of Scientific and Technical Information of China (English)

    Kalpna Rakholiya; Sumitra Chanda

    2012-01-01

    Objective: To evaluate the in vitro interaction between methanolic extracts of Terminalia catappa (Combretaceae) (T. catappa) and Carica papaya (caricaceae) (C. papaya) leaves and certain known antimicrobial drugs like penicillin G (P), ampicillin (AMP), amoxyclav (AMC), cephalothin (CEP), polymyxin B (PB), rifampicin (RIF), amikacin (AK), nilidixic acid (NA), gentamicin (GEN), chloramphenicol (C), ofloxacin (OF) against five Gram positive and five Gram negative bacteria.Methods:Evaluation of synergy interaction between plant extracts and antimicrobial agents was carried out using disc diffusion method. Results: The results of this study showed that there is an increased activity in case of combination of methanolic plant extracts and test antimicrobial agents. The more potent result was that the synergism between methanolic extract of C. papaya and antibiotics showed highest and strong synergistic effect against tested bacterial strains;though methanolic extract of C. papaya alone was not showing any antibacterial activity.Conclusions:These results indicate that combination between plant extract and the antibiotics could be useful in fighting emerging drug-resistance microorganisms.

  19. In vitro interaction of certain antimicrobial agents in combination with plant extracts against some pathogenic bacterial strains

    Institute of Scientific and Technical Information of China (English)

    Kalpna Rakholiya; Sumitra Chanda

    2012-01-01

    Objective: To evaluate the in vitro interaction between methanolic extracts of Terminalia catappa (T. catappa) (Combretaceae) and Carica papaya (C. papaya) (caricaceae) leaves and certain known antimicrobial drugs like penicillin G (P), ampicillin (AMP), amoxyclav (AMC), cephalothin (CEP), polymyxin B (PB), rifampicin (RIF), amikacin (AK), nilidixic acid (NA), gentamicin (GEN), chloramphenicol (C), ofloxacin (OF) against five Gram positive and five Gram negative bacteria. Methods: Evaluation of synergy interaction between plant extracts and antimicrobial agents was carried out using disc diffusion method. Results: The results of this study showed that there is an increased activity in case of combination of methanolic plant extracts and test antimicrobial agents. The more potent result was that the synergism between methanolic extract of C. papaya and antibiotics showed highest and strong synergistic effect against tested bacterial strains;though methanolic extract of C. papaya alone was not showing any antibacterial activity. Conclusions: These results indicate that combination between plant extract and the antibiotics could be useful in fighting emerging drug-resistance microorganisms.

  20. A Combination of Biochar-Mineral Complexes and Compost Improves Soil Bacterial Processes, Soil Quality, and Plant Properties.

    Science.gov (United States)

    Ye, Jun; Zhang, Rui; Nielsen, Shaun; Joseph, Stephen D; Huang, Danfeng; Thomas, Torsten

    2016-01-01

    Organic farming avoids the use of synthetic fertilizers and promises food production with minimal environmental impact, however this farming practice does not often result in the same productivity as conventional farming. In recent years, biochar has received increasing attention as an agricultural amendment and by coating it with minerals to form biochar-mineral complex (BMC) carbon retention and nutrient availability can be improved. However, little is known about the potential of BMC in improving organic farming. We therefore investigated here how soil, bacterial and plant properties respond to a combined treatment of BMC and an organic fertilizer, i.e., a compost based on poultry manure. In a pakchoi pot trial, BMC and compost showed synergistic effects on soil properties, and specifically by increasing nitrate content. Soil nitrate has been previously observed to increase leaf size and we correspondingly saw an increase in the surface area of pakchoi leaves under the combined treatment of BMC and composted chicken manure. The increase in soil nitrate was also correlated with an enrichment of bacterial nitrifiers due to BMC. Additionally, we observed that the bacteria present in the compost treatment had a high turnover, which likely facilitated organic matter degradation and a reduction of potential pathogens derived from the manure. Overall our results demonstrate that a combination of BMC and compost can stimulate microbial process in organic farming that result in better vegetable production and improved soil properties for sustainable farming. PMID:27092104

  1. A combination of biochar-mineral complexes and compost improves soil bacterial processes, soil quality and plant properties

    Directory of Open Access Journals (Sweden)

    JUN eYE

    2016-04-01

    Full Text Available Organic farming avoids the use of synthetic fertilizers and promises food production with minimal environmental impact, however this farming practice does not often result in the same productivity as conventional farming. In recent years, biochar has received increasing attention as an agricultural amendment and by coating it with minerals to form biochar-mineral complex (BMC carbon retention and nutrient availability can be improved. However, little is known about the potential of BMC in improving organic farming. We therefore investigated here how soil, bacterial and plant properties respond to a combined treatment of BMC and an organic fertilizer, i.e. a compost based on poultry manure. In a pakchoi pot trial, BMC and compost showed synergistic effects on soil properties, and specifically by increasing nitrate content. Soil nitrate has been previously observed to increase leaf size and we correspondingly saw an increase in the surface area of pakchoi leaves under the combined treatment of BMC and chicken manure. The increase in soil nitrate was also correlated with an enrichment of bacterial nitrifiers due to BMC. Additionally, we observed that the bacteria present in the compost treatment had a high turnover, which likely facilitated organic matter degradation and a reduction of potential pathogens derived from the manure. Overall our results demonstrate that a combination of BMC and compost can stimulate microbial process in organic farming that result in better vegetable production and improved soil properties for sustainable farming.

  2. A Combination of Biochar–Mineral Complexes and Compost Improves Soil Bacterial Processes, Soil Quality, and Plant Properties

    Science.gov (United States)

    Ye, Jun; Zhang, Rui; Nielsen, Shaun; Joseph, Stephen D.; Huang, Danfeng; Thomas, Torsten

    2016-01-01

    Organic farming avoids the use of synthetic fertilizers and promises food production with minimal environmental impact, however this farming practice does not often result in the same productivity as conventional farming. In recent years, biochar has received increasing attention as an agricultural amendment and by coating it with minerals to form biochar–mineral complex (BMC) carbon retention and nutrient availability can be improved. However, little is known about the potential of BMC in improving organic farming. We therefore investigated here how soil, bacterial and plant properties respond to a combined treatment of BMC and an organic fertilizer, i.e., a compost based on poultry manure. In a pakchoi pot trial, BMC and compost showed synergistic effects on soil properties, and specifically by increasing nitrate content. Soil nitrate has been previously observed to increase leaf size and we correspondingly saw an increase in the surface area of pakchoi leaves under the combined treatment of BMC and composted chicken manure. The increase in soil nitrate was also correlated with an enrichment of bacterial nitrifiers due to BMC. Additionally, we observed that the bacteria present in the compost treatment had a high turnover, which likely facilitated organic matter degradation and a reduction of potential pathogens derived from the manure. Overall our results demonstrate that a combination of BMC and compost can stimulate microbial process in organic farming that result in better vegetable production and improved soil properties for sustainable farming. PMID:27092104

  3. 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)

    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

  4. 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)

    Energy Technology Data Exchange (ETDEWEB)

    Norini, M.P.; Beguiristain, Th.; Leyval, C. [LIMOS UMR 7137 CNRS-UHP Nancy - Faculty of Sciences, 54 - Vandoeuvre-les-Nancy (France)

    2005-07-01

    (Medicago 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.

  5. Study the effect of bacterial 1-aminocyclopropane-1-carboxylate deaminase (ACC deaminase on resistance to salt stress in tomato plant

    Directory of Open Access Journals (Sweden)

    Maryam SADRNIA

    2011-11-01

    Full Text Available 1-aminocyclopropane-1-carboxylate deaminase (ACC deaminase produced by rhizobacteria could be remove theethylene precursor and stimulate plant growth. Aim of the work was investigation on effect of rhizosphere bacteria Pseudomonasmendocina containing plasmid carrying gene encoding ACC deaminase on resistance of tomato plant to salinity. Amplification ofacds gene in selected Pseudomonas was performed; the g e n e w a s c l o n e d i n Escherichia coli and was cloned subsequently in P.mendocina. Enzyme activity was determined in cloned Escherichia coli and cloned P. mendocina for confirmation of geneexpression. Effect of bacterial ACC deaminase on resistance of tomato plants to NaCl was studied in Pot and Greenhouse. In potexperiment, tomato plant treated by cloned P. mendocina was compared with plants treated by P. mendocina (without plasmid andcontrol group. Salinity were established by adding 172 and 207 mM of NaCl to irrigated water. Greenhouse experiments wereconducted in similar groups of bacteria in 207 mM of NaCl. Results obtained from pot experiment revealed that plants treated bycloned P. mendocina in 172 mM of NaCl was showed increasing content of growth than ones treated by P. mendocina and controlas 11%, 18.4% growth for the shoot, 16.6%, 3.7% for roots and 9.6%, 27.5% for wet weight after five weeks, respectively. In 207mM of NaCl, the results were as 14.9 %, 9.7% for shoot, 94.3%, 15.7% for roots and 96.4%, 50.6% for wet weight, respectively. Ingreenhouse experiment, results in same parameter in 207 mM of NaCl were revealed as 63.7%, 7 times for shoot, 2.8, 14 times forroots and 66.1%, 154 times for wet weight, respectively. We concluded that recombinant P. mendocina producing ACC deaminaseby reduction of ethylene content of tomato plant in high salt concentrations could result in improvement of plant resistance tosalinity.

  6. Effect of Lactic Acid Bacterial Inoculants on Rice Straw Silage

    Institute of Scientific and Technical Information of China (English)

    HUA Jinling; ZHANG Yonggen; MEN Yuxin

    2008-01-01

    The trail was designed to study on technique aspects of ensiling rice straw (RS) appended amounts of lactobacillus.There were two groups according to silage ways, baled silage (BS) and chopped silage (CS), in which lactobacillus was added at levels of 10,15 and 20 mg·kg-1,respectively and the mixtures were placed into a packed polyethylene bags and stored at room temperature for 45 days.The results showed that lactobacillus had remarkable effect on fermentation characteristics of RS. The quality of the silage was improved with the lactobacillus addition.In the experiment the optimal quality of rice straw silage (RSS) can be obtained when lactobacillus was added with 15 or 20 mg·kg-1 level.The effect of different silage methods was very remarkable to the silage quality of same material.The quality of CS was better than that of long silage, at the same time,BS was feasible on condition of eligible level of lactic acid bacteria.

  7. Effects due to rhizospheric soil application of an antagonistic bacterial endophyte on native bacterial community and its survival in soil: A case study with Pseudomonas aeruginosa from banana

    Directory of Open Access Journals (Sweden)

    Pious eThomas

    2016-04-01

    Full Text Available Effective translation of research findings from laboratory to agricultural fields is essential for the success of biocontrol or growth promotion trials employing beneficial microorganisms. The rhizosphere is to be viewed holistically as a dynamic ecological niche comprising of diverse microorganisms including competitors and noxious antagonists to the bio-inoculant. This study was undertaken to assess the effects due to the soil application of an endophytic bacterium with multiple pathogen antagonistic potential on native bacterial community and its sustenance in agricultural soil. Pseudomonas aeruginosa was employed as a model system considering its frequent isolation as an endophyte, wide antagonistic effects reported against different phytopathogens and soil pests, and that the species is a known human pathogen which makes its usage in agriculture precarious. Employing the strain ‘GNS.13.2a’ from banana, its survival in field soil and the effects upon soil inoculation were investigated by monitoring total culturable bacterial fraction as the representative indicator of soil microbial community. Serial dilution plating of uninoculated control versus P. aeruginosa inoculated soil from banana rhizosphere indicated a significant reduction in native bacterial cfu soon after inoculation compared with control soil as assessed on cetrimide- nalidixic acid selective medium against nutrient agar. Sampling on day-4 showed a significant reduction in P. aeruginosa cfu in inoculated soil and a continuous dip thereafter registering >99% reduction within one week while the native bacterial population resurged with cfu restoration on par with control. This was validated in contained trials with banana plants. Conversely, P. aeruginosa showed static cfu or proliferation in axenic-soil. Lateral introduction of soil microbiome in P. aeruginosa established soil under axenic conditions or its co-incubation with soil microbiota in suspension indicated

  8. Expressing a bacterial mercuric ion binding protein in plant for phytoremediation of heavy metals.

    Science.gov (United States)

    Hsieh, Ju-Liang; Chen, Ching-Yi; Chiu, Meng-Hsuen; Chein, Mei-Fang; Chang, Jo-Shu; Endo, Ginro; Huang, Chieh-Chen

    2009-01-30

    A specific mercuric ion binding protein (MerP) originating from transposon TnMERI1 of Bacillus megaterium strain MB1 isolated from Minamata Bay displayed good adsorption capability for a variety of heavy metals. In this study, the Gram-positive MerP protein was expressed in transgenic Arabidopsis to create a model system for phytoremediation of heavy metals. Under control of an actin promoter, the transgenic Arabidpsis showed higher tolerance and accumulation capacity for mercury, cadium and lead when compared with the control plant. Results from confocal microscopy analysis also indicate that MerP was localized at the cell membrane and vesicles of plant cells. The developed transgenic plants possessing excellent metal-accumulative ability could have potential applications in decontamination of heavy metals. PMID:18538925

  9. Changes in symbiotic and associative interrelations in a higher plant-bacterial system during space flight

    Science.gov (United States)

    Kordyum, V. A.; Man'ko, V. G.; Popova, A. F.; Shcherbak, O. H.; Mashinsky, A. L.; Nguen-Hgue-Thyok

    The miniature cenosis consisting of the water fern Azolla with its associated symbiotic nitrogen-fixing cyanobacterium Anabaena and the concomitant bacteria was investigated. Ecological closure was shown to produce sharp quantitative and qualitative changes in the number and type of concomitant bacteria. Changes in the distribution of bacterial types grown on beef-extract broth after space flight were recorded. Anabaena azollae underwent the most significant changes under spaceflight conditions. Its cell number per Azolla biomass unit increased substantially. Thus closure of cenosis resulted in a weakening of control over microbial development by Azolla. This tendency was augmented by spaceflight factors. Reduction in control exerted by macro-organisms over development of associated micro-organisms must be taken into account in constructing closed ecological systems in the state of weightlessness.

  10. A multiphasic approach for the identification of endophytic bacterial in strawberry fruit and their potential for plant growth promotion.

    Science.gov (United States)

    de Melo Pereira, Gilberto Vinícius; Magalhães, Karina Teixeira; Lorenzetii, Emi Rainildes; Souza, Thiago Pereira; Schwan, Rosane Freitas

    2012-02-01

    This study used a multiphasic approach, characterized by the simultaneous use of culture-dependent and culture-independent methods, to investigate endophytic bacterial communities in strawberry (Fragaria ananassa) fruit. A total of 92 bacterial endophytes were isolated and initially grouped by their repetitive extragenic palindromic (rep)-PCR banding pattern and biochemical features. Phylogenetic analysis of the 16S rRNA gene sequences of 45 representatives showed that the isolates belonged to the species Bacillus subtilis (eight isolates), Bacillus sp. (seven isolates), Enterobacter sp. (seven isolates), Enterobacter ludwigii (six isolates), Lactobacillus plantarum (six isolates), Pseudomonas sp. (five isolates), Pantoea punctata (three isolates), and Curtobacterium citreum (three isolates). Nucleic acids were extracted from the strawberry fruit and subjected to 16S rRNA gene directed polymerase chain reaction denaturing gradient gel electrophoresis (16S rRNA PCR-DGGE). The species B. subtilis, Enterobacter sp., and Pseudomonas sp. were detected both by isolation and DGGE. The DGGE fingerprints of total bacterial DNA did not exhibit bands corresponding to several of the representative species isolated in the extinction dilution (L. plantarum, C. citreum, and P. punctata). In contrast, bands in the DGGE profile that were identified as relatives of Arthrobacter sp. and one uncultivable Erythrobacter sp. were not recovered by cultivation techniques. After isolation, the nitrogen fixation ability and the in vitro production of indole-3-acetic acid (IAA) equivalents and siderophores were evaluated. A high percentage of isolates were found to possess the ability to produce siderophores and IAA equivalents; however, only a few isolates belonging to the genera Pseudomonas and Enterobacter showed the ability to fix nitrogen. Plant growth promotion was evaluated under greenhouse conditions and revealed the ability of the Bacillus strains to enhance the number of leaves

  11. Bacterial biofilm formation inhibitory activity revealed for plant derived natural compounds.

    Science.gov (United States)

    Artini, M; Papa, R; Barbato, G; Scoarughi, G L; Cellini, A; Morazzoni, P; Bombardelli, E; Selan, L

    2012-01-15

    Use of herbal plant remedies to treat infectious diseases is a common practice in many countries in traditional and alternative medicine. However to date there are only few antimicrobial agents derived from botanics. Based on microbiological screening tests of crude plant extracts we identified four compounds derived from Krameria, Aesculus hippocastanum and Chelidonium majus that showed a potentially interesting antimicrobial activity. In this work we present an in depth characterization of the inhibition activity of these pure compounds on the formation of biofilm of Staphylococcus aureus as well as of Staphylococcus epidermidis strains. We show that two of these compounds possess interesting potential to become active principles of new drugs. PMID:22182580

  12. Impact of sampling depth and plant species on local environmental conditions, microbiological parameters and bacterial composition in a mercury contaminated salt marsh

    International Nuclear Information System (INIS)

    Highlights: ► Vegetated habitat contained distinct bacterial communities. ► Variation in bacterial composition with depth differed between plant species. ► There is evidence of an effect of mercury concentration on bacterial composition. ► Depth and sampling depth explained almost 70% of the variation in bacterial composition. - Abstract: We compare the environmental characteristics and bacterial communities associated with two rushes, Juncus maritimus and Bolboschoenus maritimus, and adjacent unvegetated habitat in a salt marsh subjected to historical mercury pollution. Mercury content was higher in vegetated than unvegetated habitat and increased with sampling depth. There was also a significant relationship between mercury concentration and bacterial composition. Habitat (Juncus, Bolboschoenus or unvegetated), sample depth, and the interaction between both, however, explained most of the variation in composition (∼70%). Variation in composition with depth was most prominent for the unvegetated habitat, followed by Juncus, but more constrained for Bolboschoenus habitat. This constraint may be indicative of a strong plant–microbe ecophysiological adaptation. Vegetated habitat contained distinct bacterial communities associated with higher potential activity of aminopeptidase, β-glucosidase and arylsulphatase and incorporation rates of 14C-glucose and 14C-acetate. Communities in unvegetated habitat were, in contrast, associated with both higher pH and proportion of sulphate reducing bacteria.

  13. Preparation of plants containing bacterial enzyme for degradation of polychlorinated biphenyls

    Czech Academy of Sciences Publication Activity Database

    Francová, K.; Surá, M.; Macek, Tomáš; Szekeres, M.; Bancos, S.; Demnerová, K.; Sylvestre, M.; Macková, M.

    2003-01-01

    Roč. 12, č. 3 (2003), s. 309-313. ISSN 1018-4619 Institutional research plan: CEZ:AV0Z4055905 Keywords : transgenic plants * polychlorinated biphenyls * phytoremediation Subject RIV: DK - Soil Contamination ; De-contamination incl. Pesticides Impact factor: 0.325, year: 2003

  14. Autohydrolysis of plant xylans by apoplastic expression of thermophilic bacterial endo-xylanases

    DEFF Research Database (Denmark)

    Borkhardt, Bernhard; Harholt, Jesper; Ulvskov, Peter Bjarne; Ahring, Birgitte Kiær; Jørgensen, Bodil; Brinch-Pedersen, Henrik

    2010-01-01

    The genes encoding the two endo-xylanases XynA and XynB from the thermophilic bacterium Dictyoglomus thermophilum were codon optimized for expression in plants. Both xylanases were designed to be constitutively expressed under the control of the CaMV 35S promoter and targeted to the apoplast. Tra...

  15. Metabolic behavior of bacterial biological control agents in soil and plant rhizospheres

    Science.gov (United States)

    Biological control provides an attractive alternative to chemical pesticides for the control of plant diseases. To date, however, few biocontrol products have been developed successfully at the commercial level. This stems largely from variability in disease control performance that is often obser...

  16. Developing Soil Microbial Inoculants for Pest Management: Can One Have Too Much of a Good Thing?

    Science.gov (United States)

    Gadhave, Kiran R; Hourston, James E; Gange, Alan C

    2016-04-01

    Soil microbes present a novel and cost-effective method of increasing plant resistance to insect pests and thus create a sustainable opportunity to reduce current pesticide application. However, the use of microbes in integrated pest management programs is still in its infancy. This can be attributed primarily to the variations in microbial inoculum performance under laboratory and field conditions. Soil inoculants containing single, indigenous microbial species have shown promising results in increasing chemical defenses of plants against foliar feeding insects. Conversely, commercial inoculants containing multiple species tend to show no effects on herbivore infestation in the field. We present here a simple model that endeavours to explain how single and multiple species in microbial inoculants differentially govern insect population dynamics via changes in plant chemical profiles. We discuss further how this knowledge can be applied to manipulate soil microbial species and develop 'tailored' microbial inoculants that could be used in plant protection against antagonists. PMID:27059329

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

    Science.gov (United States)

    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. PMID:25391485

  18. Increased Biomass of Nursery-Grown Douglas-Fir Seedlings upon Inoculation with Diazotrophic Endophytic Consortia

    Directory of Open Access Journals (Sweden)

    Zareen Khan

    2015-10-01

    Full Text Available Douglas-fir (Pseudotsuga menziesii seedlings are periodically challenged by biotic and abiotic stresses. The ability of endophytes to colonize the interior of plants could confer benefits to host plants that may play an important role in plant adaptation to environmental changes. In this greenhouse study, nursery-grown Douglas-fir seedlings were inoculated with diazotrophic endophytes previously isolated from poplar and willow trees and grown for fifteen months in nutrient-poor conditions. Inoculated seedlings had significant increases in biomass (48%, root length (13% and shoot height (16% compared to the control seedlings. Characterization of these endophytes for symbiotic traits in addition to nitrogen fixation revealed that they can also solubilize phosphate and produce siderophores. Colonization was observed through fluorescent microscopy in seedlings inoculated with gfp- and mkate-tagged strains. Inoculation with beneficial endophytes could prove to be valuable for increasing the production of planting stocks in forest nurseries.

  19. Antibacterial Activity of Cinnamaldehyde and Estragole Extracted from Plant Essential Oils against Pseudomonas syringae pv. actinidiae Causing Bacterial Canker Disease in Kiwifruit.

    Science.gov (United States)

    Song, Yu-Rim; Choi, Min-Seon; Choi, Geun-Won; Park, Il-Kwon; Oh, Chang-Sik

    2016-08-01

    Pseudomonas syringae pv. actinidiae (Psa) causes bacterial canker disease in kiwifruit. Antibacterial activity of plant essential oils (PEOs) originating from 49 plant species were tested against Psa by a vapor diffusion and a liquid culture assays. The five PEOs from Pimenta racemosa, P. dioica, Melaleuca linariifolia, M. cajuputii, and Cinnamomum cassia efficiently inhibited Psa growth by either assays. Among their major components, estragole, eugenol, and methyl eugenol showed significant antibacterial activity by only the liquid culture assay, while cinnamaldehyde exhibited antibacterial activity by both assays. The minimum inhibitory concentrations (MICs) of estragole and cinnamaldehyde by the liquid culture assay were 1,250 and 2,500 ppm, respectively. The MIC of cinnamaldehyde by the vapor diffusion assay was 5,000 ppm. Based on the formation of clear zones or the decrease of optical density caused by these compounds, they might kill the bacterial cells and this feature might be useful for managing the bacterial canker disease in kiwifruit. PMID:27493612

  20. 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. PMID:26336850

  1. 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.

  2. Analysis of bacterial community structures in two sewage treatment plants with different sludge properties and treatment performance by nested PCR-DGGE method

    Institute of Scientific and Technical Information of China (English)

    LIU Xin-chun; ZHANG Yu; YANG Min; WANG Zhen-yu; LV Wen-zhou

    2007-01-01

    The bacterial community structures in two sewage treatment plants with different processes and performance were investigated by denaturing gradient gel electrophoresis (DGGE) of nested polymerase chain reaction (nested PCR) amplified 16S rRNA gene fragments with group-specific primers. Samples of raw sewage and treated effluents were amplified using the whole-cell PCR method, and the activated sludge samples were amplified using the extracted genomic DNA before the PCR products were loaded on the same DGGE gel for bacterial community analysis. Ammonia-oxidizing bacterial and actinomycetic community analysis were also carried out to investigate the relationship between specific population structures and system or sludge performance. The two plants demonstrated a similarity in bacterial community structures of raw sewage and activated sludge, but they had different effluent populations. Many dominant bacterial populations of raw sewage did not appear in the activated sludge samples, suggesting that the dominant bacterial populations in raw sewage might not play an important role during wastewater treatment. Although the two plants had different sludge properties in terms of settleability and foam forming ability, they demonstrated similar actinomycetic community structures. For activated sludge with bad settling performance, the treated water presented a similar DGGE pattern with that of activated sludge, indicating the nonselective washout of bacteria from the system. The plant with better ammonium removal efficiency showed higher ammonia-oxidizing bacteria (AOB) species richness. Analysis of sequencing results showed that the major populations in raw sewage were uncultured bacterium, while in activated sludge the predominant populations were beta proteobacteria.

  3. Plant Ribosomal Proteins, RPL12 and RPL19, Play a Role in Nonhost Disease Resistance against Bacterial Pathogens.

    Science.gov (United States)

    Nagaraj, Satish; Senthil-Kumar, Muthappa; Ramu, Vemanna S; Wang, Keri; Mysore, Kirankumar S

    2015-01-01

    Characterizing the molecular mechanism involved in nonhost disease resistance is important to understand the adaptations of plant-pathogen interactions. In this study, virus-induced gene silencing (VIGS)-based forward genetics screen was utilized to identify genes involved in nonhost resistance in Nicotiana benthamiana. Genes encoding ribosomal proteins, RPL12 and RPL19, were identified in the screening. These genes when silenced in N. benthamiana caused a delay in nonhost bacteria induced hypersensitive response (HR) with concurrent increase in nonhost bacterial multiplication. Arabidopsis mutants of AtRPL12 and AtRPL19 also compromised nonhost resistance. The studies on NbRPL12 and NbRPL19 double silenced plants suggested that both RPL12 and RPL19 act in the same pathway to confer nonhost resistance. Our work suggests a role for RPL12 and RPL19 in nonhost disease resistance in N. benthamiana and Arabidopsis. In addition, we show that these genes also play a minor role in basal resistance against virulent pathogens. PMID:26779226

  4. Plant Ribosomal Proteins, RPL12 and RPL19, Play a Role in Nonhost Disease Resistance against Bacterial Pathogens

    Science.gov (United States)

    Nagaraj, Satish; Senthil-Kumar, Muthappa; Ramu, Vemanna S.; Wang, Keri; Mysore, Kirankumar S.

    2016-01-01

    Characterizing the molecular mechanism involved in nonhost disease resistance is important to understand the adaptations of plant-pathogen interactions. In this study, virus-induced gene silencing (VIGS)-based forward genetics screen was utilized to identify genes involved in nonhost resistance in Nicotiana benthamiana. Genes encoding ribosomal proteins, RPL12 and RPL19, were identified in the screening. These genes when silenced in N. benthamiana caused a delay in nonhost bacteria induced hypersensitive response (HR) with concurrent increase in nonhost bacterial multiplication. Arabidopsis mutants of AtRPL12 and AtRPL19 also compromised nonhost resistance. The studies on NbRPL12 and NbRPL19 double silenced plants suggested that both RPL12 and RPL19 act in the same pathway to confer nonhost resistance. Our work suggests a role for RPL12 and RPL19 in nonhost disease resistance in N. benthamiana and Arabidopsis. In addition, we show that these genes also play a minor role in basal resistance against virulent pathogens. PMID:26779226

  5. Maize growth promotion by inoculation with Azospirillum brasilense and metabolites of Rhizobium tropici enriched on lipo-chitooligosaccharides (LCOs).

    Science.gov (United States)

    Marks, Bettina Berquó; Megías, Manuel; Ollero, Francisco Javier; Nogueira, Marco Antonio; Araujo, Ricardo Silva; Hungria, Mariangela

    2015-12-01

    There is an increasing interest in the development and use of inoculants carrying plant growth-promoting bacteria (PGPB) in crops of agronomic interest. The great majority of the inoculants commercialized worldwide contain rhizobia for legume crops, but the use of PGPB as Azospirillum spp. for non-legume is expanding, as well as of inoculants combining microorganisms and microbial metabolites. In this study we evaluated the effects of inoculants containing Azospirillum brasilense with or without metabolites of Rhizobium tropici strain CIAT 899 highly enriched in lipo-chitooligosaccharides (LCOs) in six field experiments performed for three summer crop seasons in Brazil with maize (Zea mays L.). Inoculants and metabolites were applied either at sowing by seed inoculation, or by leaf spray at the V3 stage of plant growth. Improvement in shoot dry weight (SDW) and total N accumulated in shoots (TNS) by single, but especially by dual inoculation was observed in some of the experiments. Statistically significant increases in grain yield in relation to the non-inoculated control were observed in five out of six experiments when maize was inoculated with Azospirillum supplied with enriched metabolites of R. tropici applied by seed or leaf spray inoculation. The results give strength to the development of a new generation of inoculants carrying microorganisms and microbial molecules. PMID:26567001

  6. Growth and (137)Cs uptake and accumulation among 56 Japanese cultivars of Brassica rapa, Brassica juncea and Brassica napus grown in a contaminated field in Fukushima: Effect of inoculation with a Bacillus pumilus strain.

    Science.gov (United States)

    Djedidi, Salem; Kojima, Katsuhiro; Ohkama-Ohtsu, Naoko; Bellingrath-Kimura, Sonoko Dorothea; Yokoyama, Tadashi

    2016-06-01

    Fifty six local Japanese cultivars of Brassica rapa (40 cultivars), Brassica juncea (10 cultivars) and Brassica napus (6 cultivars) were assessed for variability in growth and (137)Cs uptake and accumulation in association with a Bacillus pumilus strain. Field trial was conducted at a contaminated farmland in Nihonmatsu city, in Fukushima prefecture. Inoculation resulted in different responses of the cultivars in terms of growth and radiocesium uptake and accumulation. B. pumilus induced a significant increase in shoot dry weight in 12 cultivars that reached up to 40% in one B. rapa and three B. juncea cultivars. Differences in radiocesium uptake were observed between the cultivars of each Brassica species. Generally, inoculation resulted in a significant increase in (137)Cs uptake in 22 cultivars, while in seven cultivars it was significantly decreased. Regardless of plant cultivar and bacterial inoculation, the transfer of (137)Cs to the plant shoots (TF) varied by a factor of up to 5 and it ranged from to 0.011 to 0.054. Five inoculated cultivars, showed enhanced shoot dry weights and decreased (137)Cs accumulations, among which two B. rapa cultivars named Bitamina and Nozawana had a significantly decreased (137)Cs accumulation in their shoots. Such cultivars could be utilized to minimize the entry of radiocesium into the food chain; however, verifying the consistency of their radiocesium accumulation in other soils is strongly required. Moreover, the variations in growth and radiocesium accumulation, as influenced by Bacillus inoculation, could help selecting well grown inoculated Brassica cultivars with low radiocesium accumulation in their shoots. PMID:26986237

  7. Enhancement of plant growth and decontamination of nickel-spiked soil using PGPR.

    Science.gov (United States)

    Tank, Neelam; Saraf, Meenu

    2009-04-01

    Phytoremediation i.e. the use of plants to adsorb, accumulate or detoxify contaminants is an emerging area of interest. A viable technology needs optimum biomass production in metal contaminated soil. Five strains of microbes were selected after testing their potential as plant growth promoters, on the basis of their phosphate solubilization ability, IAA, siderophore and HCN production and biocontrol potentials. They were examined for growth in synthetic medium supplemented with nickel and their MIC (2 mM) was determined. These isolates were also able to grow and produce siderophores in presence of heavy metals like Ni, Zn and Cd. A positive response of bacterial inoculants was observed in chickpea plants towards toxic effect of nickel present in soil at different concentration (0, 1 and 2 mM). Bacterial inoculants enhanced fresh and dry weight of plants even at 2 mM nickel concentration. Pot experiments indicated that presence of nickel at upto 1 mM enhanced plant growth compared to uninoculated nickel free plants. The accumulation of nickel/plant was just 50% in Pseudomonas inoculated plants as compared to uninoculated plants with 2 mM nickel concentration along with increased biomass. The results suggest the use of these PGPR to enhance plant growth in nickel-spiked land and remediate nickel from contaminated sites. PMID:18798171

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

    Directory of Open Access Journals (Sweden)

    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

  9. Crescimento, parâmetros biofísicos e aspectos anatômicos de plantas jovens de seringueira inoculadas com fungo micorrízico arbuscular Glomus clarum Growth, biophysical parameters and anatomical aspects of young rubber tree plants inoculated with arbuscular mycorrhizal fungi Glomus clarum

    Directory of Open Access Journals (Sweden)

    Patrícia Fabian de Araújo Diniz

    2010-03-01

    Full Text Available Fungos micorrízicos são reconhecidamente benéficos quando em associação às plantas por favorecerem seu crescimento e desenvolvimento. Apesar de pouco comum para a seringueira, a inoculação artificial de fungos micorrízicos arbusculares (FMAs tem se mostrado uma alternativa para a redução no uso de fertilizantes e pesticidas nas culturas, bem como para a formação de mudas, visando obtenção de porta-enxertos precoces e bem nutridos. O estudo objetivou avaliar o efeito da inoculação do FMA Glomus clarum no crescimento e características biofísicas e anatômicas de plantas jovens de seringueira. Os tratamentos consistiram de plantas inoculadas com o fungo Glomus clarum adubadas com 50 ppm de fósforo (mic+50P, plantas não inoculadas adubadas com 50 ppm de fósforo (s/mic+50P e plantas não inoculadas adubadas com 500 ppm de fósforo (s/mic+500P. Constatou-se que as plantas micorrizadas apresentaram altura e diâmetro dos caules, matéria seca da parte aérea, densidade estomática e área foliar, semelhantes às plantas s/mic+500P. Maior acúmulo de matéria seca de raiz, maior taxa de transpiração, menor resistência estomática e menor temperatura foliar foram observadas para as plantas micorrizadas. As análises anatômicas das raízes evidenciam a ocorrência de alterações no tecido vascular, com aumento no número de pólos de xilema das raízes das plantas micorrizadas.Mycorrhizal fungi are beneficial when associated with plants because they favor growth and develop. Although infrequent, artificial inoculation of arbuscular mycorrhizal fungi (AMF has become an alternative to reduce the use of fertilizers and pesticides in crops, as well as for the formation of seedlings, to obtain precocious and well fed rootstocks. The objective of the study was to evaluate the effect of inoculation of AMF Glomus clarum on growth and biophysical and anatomical characteristics of young rubber trees. The treatments consist of plants

  10. Antimicrobial activity of plant essential oils against bacterial and fungal species involved in food poisoning and/or food decay.

    Science.gov (United States)

    Lixandru, Brînduşa-Elena; Drăcea, Nicoleta Olguţa; Dragomirescu, Cristiana Cerasella; Drăgulescu, Elena Carmina; Coldea, Ileana Luminiţa; Anton, Liliana; Dobre, Elena; Rovinaru, Camelia; Codiţă, Irina

    2010-01-01

    The currative properties of aromatic and medicinal plants have been recognized since ancient times and, more recently, the antimicrobial activity of plant essential oils has been used in several applications, including food preservation. The purpose of this study was to create directly comparable, quantitative data on the antimicrobial activity of some plant essential oils prepared in the National Institute of Research-Development for Chemistry and Petrochemistry, Bucharest to be used for the further development of food packaging technology, based on their antibacterial and antifungal activity. The essential oils extracted from thyme (Thymus vulgaris L.), basil (Ocimum basilicum L.), coriander (Coriandrum sativum L.), rosemary (Rosmarinus officinalis L.), sage (Salvia officinalis L.), fennel (Foeniculum vulgare L.), spearmint (Mentha spicata L.) and carraway (Carum carvi L.) were investigated for their antimicrobial activity against eleven different bacterial and three fungal strains belonging to species reported to be involved in food poisoning and/or food decay: S. aureus ATCC 25923, S. aureus ATCC 6538, S. aureus ATCC 25913, E. coli ATCC 25922, E. coli ATCC 35218, Salmonella enterica serovar Enteritidis Cantacuzino Institute Culture Collection (CICC) 10878, Listeria monocytogenes ATCC 19112, Bacillus cereus CIP 5127, Bacillus cereus ATCC 11778, Candida albicans ATCC 10231, Aspergillus niger ATCC 16404, Penicillium spp. CICC 251 and two E. coli and Salmonella enterica serovar Enteritidis clinical isolates. The majority of the tested essential oils exibited considerable inhibitory capacity against all the organisms tested, as supported by growth inhibition zone diameters, MICs and MBC's. Thyme, coriander and basil oils proved the best antibacterial activity, while thyme and spearmint oils better inhibited the fungal species. PMID:21462837

  11. The response of maize (Zea mays L.) plant assisted with bacterial consortium and fertilizer under oily sludge.

    Science.gov (United States)

    Shahzad, Asim; Saddiqui, Samina; Bano, Asghari

    2016-05-01

    The objective of this study was to evaluate the role of PGPR consortium and fertilizer alone and in combination on the physiology of maize grown under oily sludge stress environment as well on the soil nutrient status. Consortium was prepared from Bacillus cereus (Acc KR232400), Bacillus altitudinis (Acc KF859970), Comamonas (Delftia) belonging to family Comamonadacea (Acc KF859971) and Stenotrophomonasmaltophilia (Acc KF859973). The experiment was conducted in pots with complete randomized design with four replicates and kept in field. Oily sludge was mixed in ml and Ammonium nitrate and Diammonium phosphate (DAP) were added at 70 ug/g and 7ug/g at sowing. The plant was harvested at 21 d for estimation of protein, proline and antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD). To study the degradation, total petroleum hydrocarbon was extracted by soxhelt extraction and extract was analyzed by GC-FID at different period after incubation. Combined application of consortium and fertilizer enhanced the germination %, protein and, proline content by 90,130 and 99% higher than untreated maize plants. Bioavailability of macro and micro nutrient was also enhanced with consortium and fertilizer in oily sludge. The consortium and fertilizer in combined treatment decreased the superoxide dismutase (SOD), peroxidase dismutase (POD) of the maize leaves grown in oily sludge. Degradation of total petroleum hydrocarbon (TPHs) was 59% higher in combined application of consortium and fertilizer than untreated maize at 3 d. The bacterial consortium can enhanced the maize tolerance to oily sludge and enhanced degradation of total petroleum hydrocarbon (TPHs). The maize can be considered as tolerant plant species to remediate oily sludge contaminated soils. PMID:26587972

  12. Characterization of Bacterial Community Structure and Diversity in Rhizosphere Soils of Three Plants in Rapidly Changing Salt Marshes Using 16S rDNA

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The structure and diversity of the bacterial communities in rhizosphere soils of native Phragmites australis and Scirpus mariqueter and alien Spartina alterniflora in the Yangtze River Estuary were investigated by constructing 16S ribosomal DNA (rDNA) clone libraries. The bacterial diversity was quantified by placing the clones into operational taxonomic unit (OTU) groups at the level of sequence similarity of > 97%. Phylogenetic analysis of the resulting 398 clone sequences indicated a high diversity of bacteria in the rhizosphere soils of these plants. The members of Alphaproteobacteria,Betaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria of the phylum Proteobacteria were the most abundant in rhizobacteria. Chao 1 nonparametric diversity estimator coupled with the reciprocal of Simpson's index (1/D) was applied to sequence data obtained from each library to evaluate total sequence diversity and quantitatively compare the level of dominance. The results showed that Phragmites, Scirpus, and Spartina rhizosphere soils contained 200, 668, and 382 OTUs, respectively. The bacterial communities in the Spartina and Phragmites rhizosphere soils displayed species dominance revealed by 1/D, whereas the bacterial community in Scirpus rhizosphere soil had uniform distributions of species abundance. Overall, analysis of 16S rDNA clone libraries from the rhizosphere soils indicates that the changes in bacterial composition may occur concomitantly with the shift of species composition in plant communities.

  13. Metabolic products of PCB degradation and their fate in plant and bacterial cells

    Czech Academy of Sciences Publication Activity Database

    Frančová, Kateřina; Sylvestre, M.; Macek, Tomáš; Macková, Martina

    Praha: VŠCHT Praha, 2007 - (Macková, M.; Macek, T.; Demnerová, K.; Pazlar, V.). s. 37 ISBN 978-80-7080-025-6. [Symposium on Biosorption and Bioremediation /4./. 26.08.2007-30.08.2007, Praha] R&D Projects: GA ČR GA203/06/0563; GA MŠk 2B06156 Institutional research plan: CEZ:AV0Z40550506 Keywords : chlorobenzoic acids * polychlorinated biphenyls * plant-bacteria interactions Subject RIV: EI - Biotechnology ; Bionics

  14. Metabolic products of PCB degradation and their fate in plant and bacterial cells

    Czech Academy of Sciences Publication Activity Database

    Frančová, K.; Sylvestre, M.; Macek, Tomáš; Macková, Martina

    Praha: VŠCHT, 2007 - (Macková, M.; Macek, T.; Demnerová, K.; Pazlar, V.; Nováková, M.), s. 70-73 ISBN 978-80-7080-026-3. [Symposium on Biosorption and Bioremediation /4./. Praha (CZ), 26.08.2007-30.08.2007] R&D Projects: GA ČR GA203/06/0563; GA MŠk 2B06156 Institutional research plan: CEZ:AV0Z40550506 Keywords : chlorobenzoic acids * polychlorinated biphenyls * rhizoremediation * plant-bacteria interactions Subject RIV: EI - Biotechnology ; Bionics

  15. Deciphering Cyanide-Degrading Potential of Bacterial Community Associated with the Coking Wastewater Treatment Plant with a Novel Draft Genome.

    Science.gov (United States)

    Wang, Zhiping; Liu, Lili; Guo, Feng; Zhang, Tong

    2015-10-01

    Biotreatment processes fed with coking wastewater often encounter insufficient removal of pollutants, such as ammonia, phenols, and polycyclic aromatic hydrocarbons (PAHs), especially for cyanides. However, only a limited number of bacterial species in pure cultures have been confirmed to metabolize cyanides, which hinders the improvement of these processes. In this study, a microbial community of activated sludge enriched in a coking wastewater treatment plant was analyzed using 454 pyrosequencing and Illumina sequencing to characterize the potential cyanide-degrading bacteria. According to the classification of these pyro-tags, targeting V3/V4 regions of 16S rRNA gene, half of them were assigned to the family Xanthomonadaceae, implying that Xanthomonadaceae bacteria are well-adapted to coking wastewater. A nearly complete draft genome of the dominant bacterium was reconstructed from metagenome of this community to explore cyanide metabolism based on analysis of the genome. The assembled 16S rRNA gene from this draft genome showed that this bacterium was a novel species of Thermomonas within Xanthomonadaceae, which was further verified by comparative genomics. The annotation using KEGG and Pfam identified genes related to cyanide metabolism, including genes responsible for the iron-harvesting system, cyanide-insensitive terminal oxidase, cyanide hydrolase/nitrilase, and thiosulfate:cyanide transferase. Phylogenetic analysis showed that these genes had homologs in previously identified genomes of bacteria within Xanthomonadaceae and even presented similar gene cassettes, thus implying an inherent cyanide-decomposing potential. The findings of this study expand our knowledge about the bacterial degradation of cyanide compounds and will be helpful in the remediation of cyanides contamination. PMID:25910603

  16. Biological and genetic factors regulating natural competence in a bacterial plant pathogen.

    Science.gov (United States)

    Kung, Stephanie H; Almeida, Rodrigo P P

    2014-01-01

    For naturally competent bacteria, spatially structured growth can provide an environment for enhanced horizontal gene transfer through transformation and recombination. DNA is often present in the extracellular environment, such as in the extracellular matrix of biofilms, and the lysis of a single cell can result in high local DNA concentrations. Xylella fastidiosa is a naturally competent plant pathogen that typically lives in a surface-attached state, yet previous work characterizing the competence of this organism was conducted with planktonic cells in liquid environments. Here, we show that transformation and recombination efficiencies are two to three orders of magnitude higher for cells grown on solid compared with liquid media, with maximum recombination efficiencies of about 10(-3). Cells were highly competent throughout their exponential growth phase, with no significant change in recombination efficiencies until population growth rates began to slow. Mutations in type IV pili, competency-related, and cell-cell signalling genes significantly impacted the ability of X. fastidiosa to acquire and incorporate DNA. Because X. fastidiosa is highly competent when growing in a surface-attached state, as it does within its insect vectors and host plants, recombination of naturally transformed DNA could be a significant route by which horizontal gene transfer occurs in natural environments. PMID:24149707

  17. Characterization of 4-nonylphenol-degrading bacterial consortium obtained from a textile wastewater pretreatment plant.

    Science.gov (United States)

    Di Gioia, Diana; Salvadori, Laura; Zanaroli, Giulio; Coppini, Ester; Fava, Fabio; Barberio, Claudia

    2008-12-01

    4-Nonylphenol (4-NP) isomers are toxic and recalcitrant compounds often resulting, together with short-chain ethoxylated nonylphenol (NPnEO, where n is the number of ethylene oxide units), from NPnEO biodegradation in conventional activated sludge plants. In this work, a microbial consortium, defined as Consortium A, capable of removing 100 mg/L of 4-NP with no accumulation of metabolites with aromatic moiety was isolated from textile wastewaters after enrichment with 4-NP. The consortium showed remarkable degradation activities toward several short-chain NPnEO congeners. Culture-dependent techniques were used to isolate from the consortium twenty-six strains assigned to seven different amplified ribosomal DNA restriction analysis groups. Two- and three-member cocultures were prepared with the strains showing highest 4-NP-degrading capabilities, but neither the single strains nor the cocultures were as efficient in 4-NP degradation as Consortium A. FISH was used to characterize the microbial composition of Consortium A: it evidenced a strong occurrence of Proteobacteria and, in particular, of Gammaproteobacteria along with a relevant stability of the culture. Therefore, the isolated consortium has the potential of being used in the development of a biotechnological process for the tertiary treatment of effluents of activated sludge plants fed with NPnEO-contaminated wastewaters. PMID:18830582

  18. High-resolution bacterial growth inhibition profiling combined with HPLC-HRMS-SPE-NMR for identification of antibacterial constituents in Chinese plants used to treat snakebites

    DEFF Research Database (Denmark)

    Liu, Yueqiu; Nielsen, Mia; Stærk, Dan;

    2014-01-01

    Ethnopharmacogical relevance Bacterial infection is one of the main secondary infections caused by snakebite. The 88 plant species investigated in this study have been used as folk remedies for treatment of snakebite, and it is therefore the aim of this study to investigate whether the plants...... contain compounds with bacterial growth inhibition. Materials and methods The water and ethanol extracts of 88 plant species were screened at 200 μg/mL against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa for their antibacterial activity by micro-broth dilution...... assay. The most active extracts were fractionated into microplates using analytical-scale RP-HPLC, and subsequently growth inhibition was assessed for each well. The biochromatograms constructed from these assays were used to identify compounds responsible for antibacterial activity. The structures of...

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

    OpenAIRE

    Gopu Venkadesaperumal; Natrajan Amaresan; Krishna Kumar

    2015-01-01

    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 (Panto...

  20. Woody plant encroachment, and its removal, impact bacterial and fungal communities across stream and terrestrial habitats in a tallgrass prairie ecosystem.

    Science.gov (United States)

    Veach, Allison M; Dodds, Walter K; Jumpponen, Ari

    2015-10-01

    Woody plant encroachment has become a global threat to grasslands and has caused declines in aboveground richness and changes in ecosystem function; yet we have a limited understanding on the effects of these phenomena on belowground microbial communities. We completed riparian woody plant removals at Konza Prairie Biological Station, Kansas and collected soils spanning land-water interfaces in removal and woody vegetation impacted areas. We measured stream sediments and soils for edaphic variables (C and N pools, soil water content, pH) and bacterial (16S rRNA genes) and fungal (ITS2 rRNA gene repeat) communities using Illumina MiSeq metabarcoding. Bacterial richness and diversity decreased with distance from streams. Fungal richness decreased with distance from the stream in wooded areas, but was similar across landscape position while Planctomycetes and Basidiomycota relative abundance was lower in removal areas. Cyanobacteria, Ascomycota, Chytridiomycota and Glomeromycota relative abundance was greater in removal areas. Ordination analyses indicated that bacterial community composition shifted more across land-water interfaces than fungi yet both were marginally influenced by treatment. This study highlights the impacts of woody encroachment restoration on grassland bacterial and fungal communities which likely subsequently affects belowground processes and plant health in this ecosystem. PMID:26347079

  1. Field and greenhouse inoculation methods for assessment of sheath blight resistance in rice

    Directory of Open Access Journals (Sweden)

    Leila Garcês de Araújo

    2007-01-01

    Full Text Available Field and greenhouse inoculation methods were compared to determine the genetic variation for resistance toRhizoctonia solani in 38 somaclones of rice cultivar Metica-1. Rice plants in pots were inoculated with isolate 4F1 at the ageof sixty four days, with 2.0 g of the fungal culture, multiplied on rice grain and hull medium and placed on the soil surfacearound the plant. The differences among somaclones in relation to lesion height were significant and varied from 6.5 to 15.5cm. In the field trial of artificial inoculation with fungal culture, 52 days after planting, the lesion height varied from 6.2 to 17.7cm. The correlation between disease severity in the greenhouse and the field was positive and highly significant (r=0.44;P< 0.01, indicating the greenhouse inoculation as a safe method for screening germplasm for sheath blight resistance.

  2. Stability of the rhizosphere and endophytic bacterial communities associated with Arabidopsis thaliana (L.) Heynh under impact of cosmic factors

    Science.gov (United States)

    Kordium, V. A.; Adamchuk-Chala, N. I.; Moshinec, H. V.

    The orbital experiment will involve a growing of Arabidopsis plant seed to seed in the presence of a plant probiotic bacteria consortium introduced into the system The purpose of experiment is to characterize microbial community associated with Arabidopsis thaliana and determine how consortium of introduced bacteria along with the endemic plant-associated bacteria influences the plant development reproductive system and seed formation in spaceflight conditions The first study will be an examination of the survival of model bacteria in on the inoculated plant The second complex study is to examine the plant traits in particular the ultrastructure of root statocytes in order to determine whether the plant development proceeds normally under microgravity conditions on background of introduced bacteria and to assess the structural changes occurring in the cotyledons generative organs and seeds The third set of observations will concern studies of the structure of microbial community associated with Arabidopsis plants with traditional and molecular tools The fourth part of the work will be an examination of mobile genetic elements that can play a role in adaptation of bacteria to the spaceflight conditions however they may affect the stability of bacterial endo- and rhizosphere communities The final part of the proposal initiates the study of possible risk of the bacterial consortium use for a plant inoculation in spaceflight conditions An evaluation of this risk will be performed via examination of expression of the Klebsiella

  3. Peculiarities and impacts of expression of bacterial cyanophycin synthetases in plants.

    Science.gov (United States)

    Nausch, Henrik; Huckauf, Jana; Broer, Inge

    2016-02-01

    Cyanophycin (CP) can be successfully produced in plants by the ectopic expression of the CphA synthetase from Thermosynechococcus elongatus BP-1 (Berg et al. 2000), yielding up to 6.8 % of dry weight (DW) in tobacco leaf tissue and 7.5 % in potato tubers (Huehns et al. 2008, 2009). Though, high amounts of the polymer lead to phenotypical abnormalities in both crops. The extension of abnormalities and the maximum amount of CP tolerated depend on the compartment that CP production is localized at the tissue/crop in which CP was produced (Huehns et al. 2008, 2009; Neumann et al. 2005). It cannot be ascribed to a depletion of arginine, lysine, or aspartate, the substrates for CP synthesis. PMID:26658983

  4. PGPR BACILLUS SPECIES ISOLATED FROM TOMATO PLANT –A COMPARATIVE STUDY ON COCONUT WATER ENRICHMENT

    Directory of Open Access Journals (Sweden)

    OS Aysha, P Vinothkumar*, S Vasuki, S Valli, P Nirmala, A Reena

    2012-10-01

    Full Text Available Plant growth promoting rhizobacteria (PGPR are bacteria that colonize plant roots, they promote plant growth and reduce disease or insect damage. PGPR have been identified within many different bacterial taxa, most commercially developed PGPR for agricultural crops are species of Bacillus which form endospores that confer population stability during formulation and storage of products. Here the rhizobacteria Bacillus sp has been isolated from tomato plant and characterized with routine biochemical tests. Then the isolated rhizobacteria was enriched by inoculating with coconut water as carrier medium. The growth pattern was studied with the bacterial strain that was aseptically inoculated within coconut water in flask, coconut water within intact coconut and in nutrient broth.  The rhizobacterial culture inoculated within coconut water in coconut has multiplied to the tune of 10.0×10-6cfu ml-1within a period of 24 hrs. The bacterial strain developed mucoidal colonies on coconut water agar medium as a result of increased polysaccharide production. Seed colonization and plant growth promotion of tomato plant was more when culture was grown in coconut water was used for seed treatment.

  5. Simultaneous and successive inoculations of yeasts and lactic acid bacteria on the fermentation of an unsulfited Tannat grape must

    Directory of Open Access Journals (Sweden)

    Viviana Muñoz

    2014-01-01

    Full Text Available Interactions between yeasts and lactic acid bacteria are strain specific, and their outcome is expected to change in simultaneous alcoholic -malolactic fermentations from the pattern observed in successive fermentations. One Oenococcus oeni strain Lalvin VP41TM was inoculated with two Saccharomyces cerevisiae strains either simultaneously, three days after the yeast inoculation, or when alcoholic fermentation was close to finish. Early bacterial inoculations with each yeast strain allowed for the growth of the bacterial populations, and the length of malolactic fermentation was reduced to six days. Alcoholic fermentation by Lalvin ICV D80® yeast strain left the highest residual sugar, suggesting a negative effect of the bacterial growth and malolactic activity on its performance. In sequential inoculations the bacterial populations did not show actual growth with either yeast strain. In this strategy, both yeast strains finished the alcoholic fermentations, and malolactic fermentations took longer to finish. Lalvin ICV D80® allowed for higher viability and activity of the bacterial strain than Fermicru UY4® under the three inoculation strategies. This was beneficial for the sequential completion of both fermentations, but negatively affected the completion of alcoholic fermentation by Lalvin ICV D80® in the early bacteria additions. Conversely, Fermicru UY4®, which was rather inhibitory towards the bacteria, favored the timely completion of both fermentations simultaneously. As bacteria in early inoculations with low or no SO2 addition can be expected to multiply and interact with fermenting yeasts, not only are the yeast-bacterium strains combination and time point of the inoculation to be considered, but also the amount of bacteria inoculated.

  6. Growth, root colonization and nutrient status of Helianthemum sessiliflorum Desf. inoculated with a desert truffle Terfezia boudieri Chatin.

    Science.gov (United States)

    Slama, Awatef; Gorai, Mustapha; Fortas, Zohra; Boudabous, Abdellatif; Neffati, Mohamed

    2012-01-01

    This study aims to investigate the effects of inoculation using Terfezia boudieri Chatin ascospores (ectomycorrhizal fungus) on growth, root colonization and nutrient status of Helianthemum sessiliflorum Desf. seedlings grown in pots on two-soil types (gypseous and sandy loam). Mycorrhizal seedlings had significantly increased their height and leaf number compared to non-mycorrhizal ones. Regardless of mycorrhizal inoculation treatments, the plants growing on gypseous soil showed higher growth as compared to sandy loam one. It appears that inoculation with T. boudieri changed root morphology, increasing branching of first-order lateral roots of H. sessiliflorum seedlings. The highest root mycorrhizal colonization was recorded in inoculated seedlings on sandy loam soil (89%) when compared to gypseous one (52%). N, P and K concentrations in mycorrhizal seedlings were significantly improved by fungal inoculation. It can be concluded that inoculation of H. sessiliflorum with T. boudieri increased growth attributes and improved plant nutritional status. PMID:23961158

  7. Biochar and Plant Growth Promoting Rhizobacteria as Soil Amendments

    OpenAIRE

    Hale, Lauren Elizabeth

    2014-01-01

    The notion of introducing biochar into soil for carbon sequestration provides the impetus for studying these materials as inoculum carriers. For this goal I assessed the survival of plant growth promoting rhizobacteria (PGPR) introduced into natural soils after pre-inoculation onto biochar materials. First, molecular and culture-based methods, which involved the use of a green fluorescent protein (GFP) marker, were developed to track the introduced bacterial strain. The key findings of a case...

  8. 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.

  9. Transgenic banana plants expressing Xanthomonas wilt resistance genes revealed a stable non-target bacterial colonization structure.

    Science.gov (United States)

    Nimusiima, Jean; Köberl, Martina; Tumuhairwe, John Baptist; Kubiriba, Jerome; Staver, Charles; Berg, Gabriele

    2015-01-01

    Africa is among the continents where the battle over genetically modified crops is currently being played out. The impact of GM in Africa could potentially be very positive. In Uganda, researchers have developed transgenic banana lines resistant to banana Xanthomonas wilt. The transgenic lines expressing hrap and pflp can provide a timely solution to the pandemic. However, the impact of the transgenes expression on non-target microorganisms has not yet been investigated. To study this effect, transgenic and control lines were grown under field conditions and their associated microbiome was investigated by 16S rRNA gene profiling combining amplicon sequencing and molecular fingerprinting. Three years after sucker planting, no statistically significant differences between transgenic lines and their non-modified predecessors were detected for their associated bacterial communities. The overall gammaproteobacterial rhizosphere microbiome was highly dominated by Xanthomonadales, while Pseudomonadales and Enterobacteriales were accumulated in the pseudostem. Shannon indices revealed much higher diversity in the rhizosphere than in the pseudostem endosphere. However, the expression of the transgenes did not result in changes in the diversity of Gammaproteobacteria, the closest relatives of the target pathogen. In this field experiment, the expression of the resistance genes appears to have no consequences for non-target rhizobacteria and endophytes. PMID:26657016

  10. Field evaluation of different antibacterial antibiotic and plant extracts against bacterial blight of soybean caused by pseudomonas syringae pv. glycinea

    Directory of Open Access Journals (Sweden)

    G.P. Jagtap

    2012-08-01

    Full Text Available A field experiment was carried out to study effect of different antibacterial antibiotics and plant extracts against bacterial blight of soybean caused by Pseudomonas syringae pv. glycinea. The highest mean per cent disease incidence 35.51 per cent was observed in poushamycin treatment. The lowest mean per cent disease incidence 12.74 per cent was found in treatment streptocycline 100 ppm + Copper oxychloride (@0.25% and recorded highest seed yield (2605 kg/ha and test weight (14.33 g is superior over rest of treatments which was at par with streptocycline 100 ppm (14.28%, copper oxychloride (19.40 and Bactinashak 500 ppm (25.12%. The highest mean per cent disease incidence 28.16 per cent was observed in Tulsi and lowest mean per cent disease incidence 15.03 per cent was found in treatment Neem. Sprays of Neem is superior over rest of treatment minimum disease incidence was observed in this treatments (11.00 % and which was at par with Ginger Garlic, Onion and Tulsi.

  11. Quality assessment of truffle-inoculated seedlings in Italy: proposing revised parameters for certification

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    Domizia Donnini

    2014-08-01

    Full Text Available Aim of study: the main aims of this study were to evaluate the quality of truffle-inoculated seedlings produced by commercial nurseries in Italy and to identify their minimum requisites in terms of plant age, health, homogeneity, and cut-off percentage of inoculated Tuber and non-Tuber ectomycorrhizae, based on the analysis of an extensive sample of seedlings subjected to quality control and certification.Area of study: truffle-inoculated seedlings produced by Italian commercial nurseries.Material and Methods: analysis of truffle-inoculated seedlings for health and quality standards; recording of presence of inoculated Tuber spp. and other concurrent fungi according to the official Italian method for certification; selective amplification of ectomycorrhizal DNA by PCR species-specific primers.Main results: We showed that mycorrhization levels in truffle-inoculated seedlings increased with time after truffle-spore inoculation. The highest mean percentage of the inoculated Tuber spp., but also the highest presence of contaminants, were recorded after three years. The mycorrhization level of Tuber melanosporum and T. aestivum was higher in Corylus and Ostrya seedlings than in Q. ilex and Q. pubescens, but the latter two host species showed the lowest presence of other ectomycorrhizal fungi. Mycorrhization level distribution in truffle-inoculated seedlings of suitable batches differed very little from the distribution in only all suitable seedlings. Truffle seedlings with other Tuber spp. were very few and even absent after three years. The general quality of Italian truffle-inoculated seedlings is high but can be improved even further by revising the parameters used for their certification.Research highlights: Mycorrhization assessment in truffle-inoculated seedlings produced by commercial nurseries and a revision of the parameters of quality standards following several years of certification in Italy.Keywords: Truffle cultivation; truffle

  12. Differential plant invasiveness is not always driven by host promiscuity with bacterial symbionts.

    Science.gov (United States)

    Klock, Metha M; Barrett, Luke G; Thrall, Peter H; Harms, Kyle E

    2016-01-01

    Identification of mechanisms that allow some species to outcompete others is a fundamental goal in ecology and invasive species management. One useful approach is to examine congeners varying in invasiveness in a comparative framework across native and invaded ranges. Acacia species have been widely introduced outside their native range of Australia, and a subset of these species have become invasive in multiple parts of the world. Within specific regions, the invasive status of these species varies. Our study examined whether a key mechanism in the life history of Acacia species, the legume-rhizobia symbiosis, influences acacia invasiveness on a regional scale. To assess the extent to which species varying in invasiveness correspondingly differ with regard to the diversity of rhizobia they associate with, we grew seven Acacia species ranging in invasiveness in California in multiple soils from both their native (Australia) and introduced (California) ranges. In particular, the aim was to determine whether more invasive species formed symbioses with a wider diversity of rhizobial strains (i.e. are more promiscuous hosts). We measured and compared plant performance, including aboveground biomass, survival, and nodulation response, as well as rhizobial community composition and richness. Host promiscuity did not differ among invasiveness categories. Acacia species that varied in invasiveness differed in aboveground biomass for only one soil and did not differ in survival or nodulation within individual soils. In addition, acacias did not differ in rhizobial richness among invasiveness categories. However, nodulation differed between regions and was generally higher in the native than introduced range. Our results suggest that all Acacia species introduced to California are promiscuous hosts and that host promiscuity per se does not explain the observed differences in invasiveness within this region. Our study also highlights the utility of assessing potential

  13. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    Chowdhury, Soumitra Paul; Dietel, Kristin; Rändler, Manuela; Schmid, Michael; Junge, Helmut; Borriss, Rainer; Hartmann, Anton; Grosch, Rita

    2013-01-01

    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. PMID:23935892

  16. The Generalist Inside the Specialist: Gut Bacterial Communities of Two Insect Species Feeding on Toxic Plants Are Dominated by Enterococcus sp.

    Science.gov (United States)

    Vilanova, Cristina; Baixeras, Joaquín; Latorre, Amparo; Porcar, Manuel

    2016-01-01

    Some specialist insects feed on plants rich in secondary compounds, which pose a major selective pressure on both the phytophagous and the gut microbiota. However, microbial communities of toxic plant feeders are still poorly characterized. Here, we show the bacterial communities of the gut of two specialized Lepidoptera, Hyles euphorbiae and Brithys crini, which exclusively feed on latex-rich Euphorbia sp. and alkaloid-rich Pancratium maritimum, respectively. A metagenomic analysis based on high-throughput sequencing of the 16S rRNA gene revealed that the gut microbiota of both insects is dominated by the phylum Firmicutes, and especially by the common gut inhabitant Enterococcus sp. Staphylococcus sp. are also found in H. euphorbiae though to a lesser extent. By scanning electron microscopy, we found a dense ring-shaped bacterial biofilm in the hindgut of H. euphorbiae, and identified the most prominent bacterium in the biofilm as Enterococcus casseliflavus through molecular techniques. Interestingly, this species has previously been reported to contribute to the immobilization of latex-like molecules in the larvae of Spodoptera litura, a highly polyphagous lepidopteran. The E. casseliflavus strain was isolated from the gut and its ability to tolerate natural latex was tested under laboratory conditions. This fact, along with the identification of less frequent bacterial species able to degrade alkaloids and/or latex, suggest a putative role of bacterial communities in the tolerance of specialized insects to their toxic diet. PMID:27446044

  17. Biodegradation of soil-applied pesticides by selected strains of plant growth-promoting rhizobacteria (PGPR) and their effects on bacterial growth.

    Science.gov (United States)

    Myresiotis, Charalampos K; Vryzas, Zisis; Papadopoulou-Mourkidou, Euphemia

    2012-04-01

    A laboratory study was conducted to investigate the influence of four PGPR strains on the degradation of five soil applied pesticides and their effects on bacterial growth. Interactions of Bacillus subtilis GB03, Bacillus subtilis FZB24, Bacillus amyloliquefaciens IN937a and Bacillus pumilus SE34 with two concentrations of acibenzolar-S-methyl, metribuzin, napropamide, propamocarb hydrochloride and thiamethoxam in liquid culture and soil microcosm were studied. The degradation of acibenzolar-S-methyl by all PGPR tested in low and high concentration, was 5.4 and 5.7 times, respectively, faster than that in non-inoculated liquid culture medium. At the end of the 72-h liquid cultured experiments, 8-18, 9-11, 15-36 and 11-22% of metribuzin, napropamide, propamocarb hydrochloride and thiamethoxam, respectively, had disappeared from PGPR inoculated medium. Under the soil microcosm experimental conditions, the half-lives of acibenzolar-S-methyl incubated in the presence of PGPR strains spiked at 1.0 and 10.0 mg kg(-1) were 10.3-16.4 and 9.2-15.9 days, respectively, markedly lower compared with >34.2 days in the control. From the rest pesticides studied degradation of propamocarb hydrochloride and thiamethoxam was enhanced in the presence of B. amyloliquefaciens IN937a and B. pumilus SE34. Acibenzolar-S-methyl, propamocarb hydrochloride and thiamethoxam significantly increased the PGPR growth. However, the stimulatory effect was related to the level of pesticide spiked. PMID:21870159

  18. Effect of Arbuscular Mycorrhiza Fungi Inoculation on Growth and Up take of Mineral Nutrition in Ipomoea Aquatica.

    Directory of Open Access Journals (Sweden)

    Milton Halder

    2015-04-01

    Full Text Available A green house experiment was conducted to investigate the effect of arbuscular mycorrhiza inoculation on plant growth and uptake of mineral nutrition in Ipomoea aquatica considering the objective of using environmental friendly biofertilizer instead of chemical fertilizer. A common leafy vegetable plant Ipomoea aquatica was grown with mycorrhiza and without mycorrhiza for 42 days. After harvest the plants were analyzed for mineral nutrition concentration. Plant fresh weight, dry weight, macronutrient (P, K, Mg, Na, micronutrient (Fe, Mn, Zn concentration was higher in arbuscular mycorrhiza inoculated plant than non-mycorrhiza inoculated plant. For sustainable agriculture, introducing biofertilizer by using arbuscular mycorrhiza inoculation would be one of the most efficient techniques for replacing chemical fertilizer to meet the nutrient deficiency in nutrient deficient soils of Bangladesh.

  19. Mycorrhizal fungal establishment in agricultural soils: factors determining inoculation success.

    Science.gov (United States)

    Verbruggen, Erik; van der Heijden, Marcel G A; Rillig, Matthias C; Kiers, E Toby

    2013-03-01

    Soil biota provide a number of key ecological services to natural and agricultural ecosystems. Increasingly, inoculation of soils with beneficial soil biota is being considered as a tool to enhance plant productivity and sustainability of agricultural ecosystems. However, one important bottleneck is the establishment of viable microbial populations that can persist over multiple seasons. Here, we explore the factors responsible for establishment of the beneficial soil fungi, arbuscular mycorrhizal fungi (AMF), which can enhance the yield of a wide range of agricultural crops. We evaluate field application potential and discuss ecological and evolutionary factors responsible for application success. We identify three factors that determine inoculation success and AM fungal persistence in soils: species compatibility (can the introduced species thrive under the imposed circumstances?); field carrying capacity (the habitat niche available to AMF); and priority effects (the influence of timing and competition on the establishment of alternative stable communities). We explore how these factors can be employed for establishment and persistence of AMF. We address the importance of inoculum choice, plant choice, management practices and timing of inoculation for the successful manipulation of the resulting AMF community. PMID:23495389

  20. Field performance of maize grown from Fusarium verticillioides-inoculated seed.

    Science.gov (United States)

    Yates, I E; Widstrom, N W; Bacon, C W; Glenn, A; Hinton, D M; Sparks, D; Jaworski, A J

    2005-01-01

    Fusarium verticillioides is an important fungus occupying dual roles in the maize plant. The fungus functions as an endophyte, a fungal/host interaction beneficial to the growth of some plants. At other times, the fungus may function as a mycotoxin producing pathogen. The advantages and/or disadvantages of the endophytic relationship must be established in order to target appropriate sites for controlling diseases and mycotoxins in maize. One possibility could be to ensure seed maize is fungal free prior to planting. Reciprocal inoculations were made with two fungal isolates on seed of two maize genotypes. Yield was measured at harvest by ear and seed characters and vegetative growth at one-month intervals for plant survival, height, weight and stem diameter. Yield and vegetative growth differed among mature plants only once based on seed inoculation status. In 1998, plant weight was reduced and seed weight per ear was increased for the dent maize, GT-MAS: gk, grown from F. verticillioides RRC 374-inoculated seed compared to other seed treatments. Most vegetative characters were reduced at the first collection for Silver Queen plants grown from F. verticillioides-inoculated seed in 1997 and 1999, but not in 1998. However, no significant differences occurred among mature Silver Queen plants during any of the three growing seasons. In conclusion, yield and vegetative growth of mature maize plants grown from F. verticillioides-inoculated seed were equal to or greater than plants grown from non-inoculated seed under south Georgia field conditions during 1997, 1998, and 1999. PMID:15750733

  1. Bacterial gastroenteritis

    Science.gov (United States)

    Infectious diarrhea - bacterial gastroenteritis; Acute gastroenteritis; Gastroenteritis - bacterial ... Bacterial gastroenteritis can affect 1 person or a group of people who all ate the same food. It is ...

  2. Inoculant production in developing countries - Problems, potentials and success

    International Nuclear Information System (INIS)

    Sustainable agriculture is a long-term goal that seeks to overcome some of problems and constraints that confront the economic viability, environmental soundness and social acceptance of agricultural production systems. In this context, bio-fertilizers assume special significance particularly because they are 'eco-friendly', but also since their alternative, chemical fertilizers are expensive. Undoubtedly, the most commonly used bio-fertilizers are soil bacteria of the genus Rhizobium, but others like Azolla, Azospirillum, various cyanobacteria also contribute significant amounts of N to e.g. rice. Other bacteria like Frankia and Acetobacter contribute N to trees of the genus Casuarina and sugarcane, respectively. Furthermore, although they are rarely used as inoculants, vesicular arbuscular mycorrhizae (VAM) and phosphobacteria help countless plants solubilise and assimilate soil phosphorus. Despite these advantages, bio-fertilizers could be more widely used in developing countries. Contingent upon greater use is improved quality of the inoculants, and all aspects of their production are discussed here. (author)

  3. Study on the Effect of Different Urea Fertilizer Rates and Plant Populations on the Severity of Bacterial Blight (BB of Rice

    Directory of Open Access Journals (Sweden)

    Si Si Myint

    2007-10-01

    Full Text Available To study the effect of different urea fertilizer rates and plant populations on disease severity of bacterial blight of rice and yield lasses related to disease, the experiments including three plant populations (110000, 150000, 190000 and five urea fertilizer rates (0,56 lb, 112 lb, 168 lb and 224 lb per acre were conducted at Central Agriculture Research Institute farm in 1999 and 2000 rainy seasons. Manawthukha was used as a test variety that is susceptible to bacterial blight of rice. The disease severity could be increased by the application of urea. Although urea 112 lb per acre gave moderate disease severity than without urea, its yield is highest. The higher disease severity also showed the related effect of plant population of 150000 and above. However the combination of urea 224 lb per acre with the population of 190000 and 150000 gave the highest severity of bacterial blight disease and the minimum grain yield. The application of urea 224 lbs per acre can cause yield reduction ranging from 18.67 percent to 27.57 percent over the application of urea 112 lb per acre.

  4. Biosynthesis of isoprenoids in plants: Structure of the 2C-methyl-d-erithrytol 2,4-cyclodiphosphate synthase from Arabidopsis thaliana. Comparison with the bacterial enzymes

    OpenAIRE

    Calisto, Barbara M.; Perez-Gil, Jordi; Bergua, Maria; Querol-Audi, Jordi; Fita, Ignacio; Imperial, Santiago

    2007-01-01

    The X-ray crystal structure of the 2C-methyl-d-erythritol 2,4-cyclodiphosphate synthase (MCS) from Arabidopsis thaliana has been solved at 2.3 Å resolution in complex with a cytidine-5-monophosphate (CMP) molecule. This is the first structure determined of an MCS enzyme from a plant. Major differences between the A. thaliana and bacterial MCS structures are found in the large molecular cavity that forms between subunits and involve residues that are highly conserved among plants. In some bact...

  5. Multiplication and Viability of some Rhizobium Strains to be used as Inoculants for Agricultural Biomass Production

    OpenAIRE

    Simina Neo; Daniela Vintilă; Teodor Vintilă; Monica Dragomirescu; Marioara Nicula

    2012-01-01

    Rhizobia are well known for their capacity to establish a symbiosis with legumes. They inhabit root nodules, where they reduce atmospheric nitrogen and make it available to the plant. Biological nitrogen fixation is an important component of sustainable agriculture, and rhizobial inoculants have been applied frequently as biofertilizers. In this review we approach the subject of legumes inoculation in order to improve the nitrogen fixing capacity. In the first part of the experiment, the Rhiz...

  6. Inoculation with Azospirillum, associated with nitrogen fertilization in maize

    Directory of Open Access Journals (Sweden)

    Maria do Carmo Lana

    2012-06-01

    Full Text Available The biological nitrogen fixation is an alternative to supply the nitrogen needed for maize. The objective of this study was to evaluate the development and yield of maize in response to inoculation with Azospirillum associated with nitrogen fertilization. We conducted two field experiments in the summer harvest, the first in the 2000/2001 crop year in the region of Marechal Cândido Rondon, under conventional tillage, and second in the 2002/2003 agricultural year in the region of Cascavel, under no tillage. The experimental design in both experiments was a randomized complete block, with four replications, 2x2x2 factorial, with two levels of nitrogen at sowing (zero and 20 kg ha-1, two levels of inoculum (zero and 200 g ha-1 and two levels of nitrogen in topdressing (zero and 100 kg ha-1. There was evaluated the height of ear insertion, total plant height, leaf N content, shoot dry biomass and grain yield. The height of ear insertion and total plant height were not influenced by the factors under study. Nitrogen fertilization at sowing increased the leaf N content, causing the opposite effect when combined with inoculation. Inoculation with Azospirillum in the absence of nitrogen, provide productivity increases of 15.4% and 7.4% for 2000/2001 and 2002/2003 crops, respectively. The inoculation provided productivity similar to that obtained with 100 kg ha-1 in topdressing in crop 2000/2001, while in association with the topdressing, reduced productivity and shoot dry biomass in crop 2002/2003.

  7. Effect of amino acid application on induced resistance against citrus canker disease in lime plants

    Directory of Open Access Journals (Sweden)

    Hasabi Vahideh

    2014-07-01

    Full Text Available Citrus bacterial canker, caused by Xanthomonas citri subsp. citri (Xcc, is a destructive disease. So far, the chemicals used to control this pathogen are either ineffective or harmful to the environment. To improve control of this disease, lime (Citrus aurantifolia were treated with L-arginine, L-methionine, L-ornithine, and distilled water. Plants were inoculated with Xcc, 48 hours post treatment. Lesion diameters of inoculated leaves were evaluated four weeks after inoculation with a bacterial suspension. Changes in β-1,3-glucanase transcript levels and activity of antioxidant enzymes, catalase, peroxidase, and phenylalanine ammonia-lyase were investigated at 48 hours post treatment and 24, 48, and 72 hours post inoculation. Based on the results of phenotypic, antioxidant enzyme activity and a molecular study of the stressed plants, it was found that those plants treated with the amino acid methionine significantly increased the plant induced resistance as well as decreased the severity of disease by reducing necrotic lesion size.

  8. Characterization of plant growth promoting traits of bacterial isolates from the rhizosphere of barley (Hordeum vulgare L.) and tomato (Solanum lycopersicon L.) grown under Fe sufficiency and deficiency.

    Science.gov (United States)

    Scagliola, M; Pii, Y; Mimmo, T; Cesco, S; Ricciuti, P; Crecchio, C

    2016-10-01

    Plant Growth Promoting Bacteria (PGPB) are considered a promising approach to replace the conventional agricultural practices, since they have been shown to affect plant nutrient-acquisition processes by influencing nutrient availability in the rhizosphere and/or those biochemical processes determining the uptake at root level of nitrogen (N), phosphorus (P), and iron (Fe), that represent the major constraints for crop productivity worldwide. We have isolated novel bacterial strains from the rhizosphere of barley (Hordeum vulgare L.) and tomato (Solanum lycopersicon L.) plants, previously grown in hydroponic solution (either Fe deficient or Fe sufficient) and subsequently transferred onto an agricultural calcareous soil. PGPB have been identified by molecular tools and characterized for their capacity to produce siderophores and indole-3-acetic acid (IAA), and to solubilize phosphate. Selected bacterial isolates, showing contemporarily high levels of the three activities investigated, were finally tested for their capacity to induce Fe reduction in cucumber roots two isolates, from barley and tomato plants under Fe deficiency, significantly increased the root Fe-chelate reductase activity; interestingly, another isolate enhanced the reduction of Fe-chelate reductase activity in cucumber plant roots, although grown under Fe sufficiency. PMID:27295343

  9. Chlor-alkali plant contamination of Aussa River sediments induced a large Hg-resistant bacterial community

    Science.gov (United States)

    Baldi, Franco; Marchetto, Davide; Gallo, Michele; Fani, Renato; Maida, Isabel; Covelli, Stefano; Fajon, Vesna; Zizek, Suzana; Hines, Mark; Horvat, Milena

    2012-11-01

    A closed chlor-alkali plant (CAP) discharged Hg for decades into the Aussa River, which flows into Marano Lagoon, resulting in the large-scale pollution of the lagoon. In order to get information on the role of bacteria as mercury detoxifying agents, analyses of anions in the superficial part (0-1 cm) of sediments were conducted at four stations in the Aussa River. In addition, measurements of biopolymeric carbon (BPC) as a sum of the carbon equivalent of proteins (PRT), lipids (LIP), and carbohydrates (CHO) were performed to correlate with bacterial biomass such as the number of aerobic heterotrophic cultivable bacteria and their percentage of Hg-resistant bacteria. All these parameters were used to assess the bioavailable Hg fraction in sediments and the potential detoxification activity of bacteria. In addition, fifteen isolates were characterized by a combination of molecular techniques, which permitted their assignment into six different genera. Four out of fifteen were Gram negative with two strains of Stenotrophomonas maltophilia, one Enterobacter sp., and one strain of Brevibacterium frigoritolerans. The remaining strains (11) were Gram positive belonging to the genera Bacillus and Staphylococcus. We found merA genes in only a few isolates. Mercury volatilization from added HgCl2 and the presence of plasmids with the merA gene were also used to confirm Hg reductase activity. We found the highest number of aerobic heterotrophic Hg-resistant bacteria (one order magnitude higher) and the highest number of Hg-resistant species (11 species out of 15) at the confluence of the River Aussa and Banduzzi's channel, which transport Hg from the CAP, suggesting that Hg is strongly detoxified [reduced to Hg(0)] at this location.

  10. Effects of stage of maturity at harvest, wilting and LAB inoculant on aerobic stability of wheat silages

    DEFF Research Database (Denmark)

    Weinberg, Z.G.; Khanal, Prabhat; Chen, Y.;

    2010-01-01

    The objective was to study effects of cultivar, stage of maturity at harvest, wilting, and addition of lactic acid bacterial (LAB) inoculant at ensiling, and their interactions, on the aerobic stability of wheat silages. Wheat of two cultivars, harvested at the flowering or the milk stage...... to the results with cultivar, stage of maturity, wilting and inoculant as main effects, as well as their interactions. Cultivar and LAB inoculant had effects on silage composition and aerobic stability, with stage of maturity having an effect on aerobic losses, whereas wilting did not have effects on aerobic...

  11. Endophytic Cultivable Bacteria of the Metal Bioaccumulator Spartina maritima Improve Plant Growth but Not Metal Uptake in Polluted Marshes Soils

    Science.gov (United States)

    Mesa, Jennifer; Mateos-Naranjo, Enrique; Caviedes, Miguel A.; Redondo-Gómez, Susana; Pajuelo, Eloisa; Rodríguez-Llorente, Ignacio D.

    2015-01-01

    Endophytic bacterial population was isolated from Spartina maritima tissues, a heavy metal bioaccumulator cordgrass growing in the estuaries of Tinto, Odiel, and Piedras River (south west Spain), one of the most polluted areas in the world. Strains were identified and ability to tolerate salt and heavy metals along with plant growth promoting and enzymatic properties were analyzed. A high proportion of these bacteria were resistant toward one or several heavy metals and metalloids including As, Cu, and Zn, the most abundant in plant tissues and soil. These strains also exhibited multiple enzymatic properties as amylase, cellulase, chitinase, protease and lipase, as well as plant growth promoting properties, including nitrogen fixation, phosphates solubilization, and production of indole-3-acetic acid (IAA), siderophores and 1-aminocyclopropane-1-carboxylate (ACC) deaminase. The best performing strains (Micrococcus yunnanensis SMJ12, Vibrio sagamiensis SMJ18, and Salinicola peritrichatus SMJ30) were selected and tested as a consortium by inoculating S. maritima wild plantlets in greenhouse conditions along with wild polluted soil. After 30 days, bacterial inoculation improved plant photosynthetic traits and favored intrinsic water use efficiency. However, far from stimulating plant metal uptake, endophytic inoculation lessened metal accumulation in above and belowground tissues. These results suggest that inoculation of S. maritima with indigenous metal-resistant endophytes could mean a useful approach in order to accelerate both adaption and growth of this indigenous cordgrass in polluted estuaries in restorative operations, but may not be suitable for rhizoaccumulation purposes. PMID:26733985

  12. CO-INOCULAÇÃO DE SEMENTES DE CAUPI COM Bradyrhizobium E Paenibacillus E SUA EFICIÊNCIA NA ABSORÇÃO DE CÁLCIO, FERRO E FÓSFORO PELA PLANTA CO-INOCULATION OF CAUPI SEEDS WITH Bradyrhizobium AND Paenibacillus AND ITS EFFICIENCY ON CALCIUM IRON AND PHOSPHORUS PLANT ABSORPTION

    Directory of Open Access Journals (Sweden)

    Luiz Eduardo de Souza Fernandes da Silva

    2007-09-01

    Full Text Available

    O objetivo deste estudo foi verificar a viabilidade da co-inoculação de sementes de caupi (Vigna unguiculata (L. Walp. com bactérias fixadoras de nitrogênio dos gêneros Bradyrhizobium sp. (BR-2001 e NFB-700 e Paenibacillus polymyxa [(Loutit (L.]e sua eficiência na absorção de cálcio, ferro e fósforo pelas plantas de caupi, sob diferentes métodos de inoculação. Foi utilizado um Argissolo Amarelo coletado em fevereiro de 2002, localizado a BR 101 Norte, km 53, latitude 07º34'00'', longitude 35º00'00'' e altitude 14m, em Itapirema (Goiana, Estado de Pernambuco. As inoculações foram efetuadas na semente e no solo a uma profundidade de 3,5 cm, usando-se a cultivar IPA-205. Foram determinadas as concentrações de cálcio, ferro e fósforo na matéria seca da parte aérea das plantas de caupi. A co-inoculação do caupi com as estirpes de Bradyrhizobium sp. introduzidas no solo proporciona aumentos nas concentrações de cálcio, ferro e fósforo.

    PALAVRAS-CHAVE: Co-infecção; cálcio; ferro; fósforo; Vigna unguiculata.

    The objective of this study was to verify the viability of the co-inoculation of caupi seeds (Vigna unguiculata (L. Walp. with nitrogen fixing bacteria of Bradyrhizobium sp. (BR-2001 and NFB-700 and Paenibacillus polymyxa [(Loutit (L.] strains and their efficiency in calcium, iron, and phosphorus absorption by caupi plants under different inoculation methods. A Yellow Argisol was collected in February, 2002, located at the km 53 of BR 101 North highway, latitude 07ºSouth34'00'', longitude 35ºWest00'00'' and altitude 14m, in Itapirema (Goiana, Pernambuco State, Brazil. The inoculations were made in seeds and soil to a depth of 3.5 cm using IPA-205 cultivar. The variables evaluated were calcium, iron, and phosphorus concentration in the aerial

  13. Mine land valorization through energy maize production enhanced by the application of plant growth-promoting rhizobacteria and arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Moreira, Helena; Pereira, Sofia I A; Marques, Ana P G C; Rangel, António O S S; Castro, Paula M L

    2016-04-01

    The use of heavy metals (HM) contaminated soils to grow energy crops can diminish the negative impact of HM in the environment improving land restoration. The effect of two PGPR (B1-Chryseobacterium humi ECP37(T) and B2-Pseudomonas reactans EDP28) and an AMF (F-Rhizophagus irregularis) on growth, Cd and Zn accumulation, and nutritional status of energy maize plants grown in a soil collected from an area adjacent to a Portuguese mine was assessed in a greenhouse experiment. Both bacterial strains, especially when co-inoculated with the AMF, acted as plant growth-promoting inoculants, increasing root and shoot biomass as well as shoot elongation. Cadmium was not detected in the maize tissues and a decrease in Zn accumulation was observed for all microbial treatments in aboveground and belowground tissues-with inoculation of maize with AMF and strain B2 leading to maximum reductions in Zn shoot and root accumulation of up to 48 and 43 %, respectively. Although microbial single inoculation generally did not increase N and P levels in maize plants, co-inoculation of the PGPR and the AMF improved substantially P accumulation in roots. The DGGE analysis of the bacterial rhizosphere community showed that the samples inoculated with the AMF clustered apart of those without the AMF and the Shannon-Wiener Index (H') increased over the course of the experiment when both inoculants were present. This work shows the benefits of combined inoculation of AMF and PGPR for the growth energy maize in metal contaminated soils and their potential for the application in phytomanagement strategies. PMID:26676544

  14. Inoculation of chromium white cast iron

    Directory of Open Access Journals (Sweden)

    D. Kopyciński

    2009-01-01

    Full Text Available It has been proved that an addition of boron carbide introduced as an inoculant to the chromium white cast iron changes the structureof castings. Castings after inoculation revealed a different structure with numerous grains. Primary precipitates of chromium carbide also appeared, reducing the mechanical properties of as-cast parts. Properly established heat treatment regime makes chromium iron castings regain their, originally high, mechanical properties.

  15. Inoculation of chromium white cast iron

    OpenAIRE

    D. Kopyciński

    2009-01-01

    It has been proved that an addition of boron carbide introduced as an inoculant to the chromium white cast iron changes the structureof castings. Castings after inoculation revealed a different structure with numerous grains. Primary precipitates of chromium carbide also appeared, reducing the mechanical properties of as-cast parts. Properly established heat treatment regime makes chromium iron castings regain their, originally high, mechanical properties.

  16. Multiple inoculations of ductile iron and the effects on properties

    OpenAIRE

    Adebayo Badmos; Kelvin Fakehinde

    2015-01-01

    Multiple inoculation of ductile iron and the effects on the structure and mechanical properties have being investigated. Samples of ductile iron were produced with inoculation carried out either once or twice and with different materials as inoculants. Ferrosilicon was used for the primary inoculation and either ferrosilicon or nickel-ferrosilicon for the secondary inoculation. It is observed that the nodules produced are more and finer with multiple inoculations and the effect is more pronou...

  17. Inoculated Slightly Hypereutectic Gray Cast Irons

    Science.gov (United States)

    Chisamera, Mihai; Riposan, Iulian; Stan, Stelian; Militaru, Cristina; Anton, Irina; Barstow, Michael

    2012-03-01

    The current experimental investigation in this article was designed to characterize the structure of mold (M) and ladle (L) inoculated, low-S (0.025 wt.% S), low-Al (0.003 wt.% Al), slightly hypereutectic (CE = 4.4-4.5 wt.%) electric melted gray irons, typical for high performance thin-wall castings. It describes the effect of a Ca, Al, Zr-FeSi inoculant addition of 0-0.25 wt.% on structure characteristics, and compares to similar treatments with hypoeutectic irons (3.5-3.6 wt.% CE, 0.025 wt.% S, and 0.003 wt.% Al). A complex structure including primary graphite, austenite dendrites, and eutectic cells is obtained in hypereutectic irons, as the result of nonequilibrium solidification following the concept of a coexisting region. Dendrites appear to be distributed between eutectic cells at higher eutectic undercooling, while in inoculated irons and for lower undercooling, the eutectic cells are "reinforced" by eutectic austenite dendrites. A Zr, Ca, Al-FeSi alloy appears to be an effective inoculant in low S, low Al, gray cast irons, especially for a late inoculation technique, with beneficial effects on both graphite and austenite phases. First, inoculation influenced the nucleation of graphite/eutectic cell, and then their characteristics. A further role of these active elements directly contributed to form nucleation sites for austenite, as complex (Mn,X)S particles.

  18. Two Volatile Organic Compounds Trigger Plant Self-Defense against a Bacterial Pathogen and a Sucking Insect in Cucumber under Open Field Conditions

    Directory of Open Access Journals (Sweden)

    Choong-Min Ryu

    2013-05-01

    Full Text Available Systemic acquired resistance (SAR is a plant self-defense mechanism against a broad-range of pathogens and insect pests. Among chemical SAR triggers, plant and bacterial volatiles are promising candidates for use in pest management, as these volatiles are highly effective, inexpensive, and can be employed at relatively low concentrations compared with agrochemicals. However, such volatiles have some drawbacks, including the high evaporation rate of these compounds after application in the open field, their negative effects on plant growth, and their inconsistent levels of effectiveness. Here, we demonstrate the effectiveness of volatile organic compound (VOC-mediated induced resistance against both the bacterial angular leaf spot pathogen, Pseudononas syringae pv. lachrymans, and the sucking insect aphid, Myzus persicae, in the open field. Using the VOCs 3-pentanol and 2-butanone where fruit yields increased gave unexpectedly, a significant increase in the number of ladybird beetles, Coccinella septempunctata, a natural enemy of aphids. The defense-related gene CsLOX was induced by VOC treatment, indicating that triggering the oxylipin pathway in response to the emission of green leaf volatiles can recruit the natural enemy of aphids. These results demonstrate that VOCs may help prevent plant disease and insect damage by eliciting induced resistance, even in open fields.

  19. 岷山红三叶根际优良促生菌对其宿主生长和品质的影响%The inoculant potential of plant growth promoting rhizobacteria strains to improve the yield and quality of Trifolium pratense cv.Minshan

    Institute of Scientific and Technical Information of China (English)

    荣良燕; 姚拓; 马文彬; 李德明; 李儒仁; 张洁; 陆飒

    2014-01-01

    从岷山红三叶根际分离出高效溶磷菌,并对其分泌生长激素、拮抗病原菌特性进行测定,筛选出优良促生菌6株,根瘤菌1株,按照一定比例混合制成复合菌肥,进行盆栽试验,研究复合菌肥对岷山红三叶产量、品质及异黄酮含量的影响。结果表明:利用筛选的优良促生菌和根瘤菌研制的复合微生物菌肥符合《微生物肥料》标准(NY227-94)。75%化肥+PGPR菌肥处理使岷山红三叶干草总产量较 CK 增加4.76%,同时,该处理可提高红三叶粗蛋白、粗灰分、钙、磷含量,降低中、酸性洗涤纤维含量;50%化肥+PGPR菌肥处理对岷山红三叶的总干草产量、营养品质以及4种异黄酮的含量均没有显著影响。%Interest in plant growth promoting rhizobacteria (PGPR)has increased due to their potential contri-bution to sustainable agricultural systems by reducing environmental impact,the consumption of non-renew-able resources and input costs.This paper investigates the inoculant effect of PGPR on the hay yield and nutri-ent quality of Trifoliumpratensecv.Minshan.Six PGPR and one rhizobia strains were identified by screening for phosphate solubilization,3-indoleacetic acid (IAA)secretion and antagonism to plant pathogens.A PGPR inoculant was produced by mixing these strains and pot tests have been conducted to investigate its effects on the growth and quality of T.pratensecv.Minshan when combined with different amounts of chemical fertiliz-er.The results showed that the nitrogenase activity of the rhizobia strain was 488.2 C2 H4 nmol/(mL·h).The phosphate solubilization and IAA secreting ability of the five PGPR strains was distributed across the ranges 50.34-229.5 mg/L and 0.86-12.01 μg/mL respectively.The PGPR compound bio-fertilizer demonstrated strong antagonism to the pathogensFusariumoxysporium f.sp.cucumerinum,RhizoctoniasolaniandFusar-iumoxysporum f.niveum.The composite microbial inoculant

  20. Comparison of the bacterial community and characterization of plant growth-promoting rhizobacteria from different genotypes of Chrysopogon zizanioides (L.) Roberty (vetiver) rhizospheres.

    Science.gov (United States)

    Monteiro, Juliana Mendes; Vollú, Renata Estebanez; Coelho, Marcia Reed Rodrigues; Alviano, Celuta Sales; Blank, Arie Fitzgerald; Seldin, Lucy

    2009-08-01

    Molecular approaches [PCR-denaturing gradient gel electrophoresis (DGGE)] were used to determine whether three different vetiver (Chrysopogon zizanioides) genotypes, commercially used in Brazil and considered economically important over the world, select specific bacterial populations to coexist in their rhizospheres. DGGE profiles revealed that the predominant rhizospheric bacterial community hardly varies regarding the vetiver genotype. Moreover, using traditional cultivation methods, bacterial strains were isolated from the different rhizospheres. Colonies presenting different morphologies (83) were selected for determining their potential for plant growth promotion. More than half of the strains tested (57.8%) were amplified by PCR using nifH-based primers, specific for the enzyme nitrogenase reductase. The production of siderophores was observed in 88% of the strains, while the production of antimicrobial substances was detected in only 14.5% of the isolates when Micrococcus sp. was used as the indicator strain. Production of indole-3-acetic acid and the solubilization of phosphate were observed in 55.4% and 59% of the isolates, respectively. In total, 44 strains (53%) presented at least three characteristics of plant growth promotion and were submitted to amplified ribosomal DNA restriction analysis. Twenty-four genetic groups were formed at 100% similarity and one representative of each group was selected for their identification by partial 16S rRNA gene sequencing. They were affiliated with the genera Acinetobacter, Comamonas, Chryseobacterium, Klebsiella, Enterobacter, Pantoea, Dyella, Burkholderia, or Pseudomonas. These strains can be considered of great importance as possible biofertilizers in vetiver. PMID:19763409

  1. Combination of inoculation methods of Azospirilum brasilense with broadcasting of nitrogen fertilizer increases corn yield

    Directory of Open Access Journals (Sweden)

    Tânia Maria Müller

    2015-01-01

    Full Text Available Nitrogen (N is the most limiting nutrient for corn production. Thereby, the goal of the paper was to evaluate inoculation methods of Azospirillum brasilense in order to partially supply N required by the crop. The experiment was carried out in Guarapuava, PR, Brasil, in 2011/2012 growing season. Randomized blocks with factorial 3 inoculation methods (seed treatment, planting furrow and non-inoculated control x 5 doses of nitrogen (0, 75, 150, 225 and 300kg ha-1 x 8 replications was used as the experimental design. Leaf are index, foliar nitrogen content, total chlorophyll, grains per ear and yield were evaluated. There was significant interaction between inoculation methods and nitrogen fertilization to leaf area index, but not for yield. Inoculation with the diazotrophic bacteria provided yield increase of 702kg ha-1 for inoculation in seeding furrow and 432kg ha-1 for inoculation in seed treatment compared to the control, but both treatments did not differ between each other. Furthermore, total chlorophyll, grains per ear and yield were positively affected, with quadratic response, by the nitrogen fertilization in broadcasting

  2. Improvement of Rhizobial Inoculants: A Key Process in Sustainable Soybean Production

    Directory of Open Access Journals (Sweden)

    Mihaela Blažinkov

    2016-01-01

    Full Text Available Symbiotic nitrogen fixation has important role in sustainable soybean production because of utilization of atmospheric nitrogen for soybean nutrition. Pre-sowing soybean seed inoculation with selected rhizobial strains is used to improve the amount of symbiotically fixed nitrogen. Besides strain selection, suitable inoculant formulation is important for the success of inoculant application. The aim of this research is the evaluation of symbiotic efficiency and compatibility of Bradyrhizobium japonicum strains with soybean cultivar as well as possibility of using different inoculant formulation in soybean production. During two years of field trials in eastern Slavonia, nodule dry weight, nitrogen content in plant, seed yield, 1000 seeds weight, protein and oil content in seed were determined. Results of this study indicate that inoculant formulation as well as the use of selected strains affects nodulation, symbiotic and agronomic properties of soybean. Despite the differences in results in both experimental years, it can be concluded that the strains used as well as inoculant formulations are suitable for soybean inoculation in agroecological conditions of eastern Slavonia.

  3. Effect of Microbial Inoculants on Uptake of Nutrient Elements in Two Cultivars of Sunflower (Helianthus annuus L. in Saline Soils

    Directory of Open Access Journals (Sweden)

    Mostafa SHIRMARDI

    2010-09-01

    Full Text Available A greenhouse experiment was conducted in order to evaluate the interactive effects of microbial inoculants on uptake of nutrient elements (N, P, K, Ca, Mg, Na, Cl, Fe, Zn, Cu, Mn in two cultivars of sunflower. The trials were carried out on saline (EC = 7.6 dS m-1 calcareous soils taken from Eshtehard (Karaj region of Iran. In a factorial trial and completely randomized design (CRD, three levels of arbuscular mycorrhizal inoculants (non inoculation, inoculation withGlomus etunicatum and Glomus intradices and four levels of Pseudomonas fluorescensinoculants (non inoculation and inoculation with Pseudomonas fluorescens strains 4, 9, 12 in two cultivars of sunflower with four replications per treatments were applied. Results revealed that all of the treatments increased the N uptake in Euroflor cultivar. Moreover, in Euroflor cultivar, inoculation with Pseudomonas fluorescens strains 9 and co-inoculation of Pseudomonas fluorescens strains 4 and Glomus intradices made a significant different in phosphorous uptake, while did not make any significant change in the Master cultivar. However, bacterial and fungal treatments significantly (P < 0.05 increased uptake of micro nutrients such as Fe, Zn and Mn.

  4. Effect of arbuscular mycorrhizal fungal inoculation in combination with different organic fertilizers on maize crop in eroded soils

    International Nuclear Information System (INIS)

    A pot experiment was conducted to study the effect of inoculating maize (Zea mays L. Azam) with Arbuscular mycorrhizal (AM) fungi in 2 different series of North West Pakistan during the year 2007. Data showed significant increase in shoots and roots yield of maize with the inoculation of AM fungi alone and in combination with farm yard manure (FYM), poultry manure (PM) and humic acid (HA) over control and N-P-K treatments. Accumulation of N by maize shoots increased significantly by the addition of HA, PM and FYM plus N-P-K with or without inoculation of AM fungi over the treatments of N-P-K and control. Plants P accumulation increased significantly over control and N-P-K treatments with the inoculation of AM fungi alone and in combination with FYM, PM and HA in missa soil series. In missa gullied soil series, significantly increased plants P accumulation was noted by the treatments of AM inoculation with PM followed by HA. Accumulation of Mn by maize shoots increased significantly with AM inoculation with HA and PM over all other treatments, Fe increased with PM, HA and FYM. Plants Cu accumulation in missa series increased significantly over control and N-P-K treatments by AM alone and in combination with PM, FYM and HA and by AM fungi with PM, FYM and HA in missa gullied series. Maximum Mycorrhizal root infection rate of 51 % was recorded in the treatment of AM fungal inoculation with HA followed by the treatment inoculated with AM fungi with FYM. In missa gullied soil series, Maximum (59 %) and significantly increased roots infection rates over all treatments were observed in the treatment of AM fungal inoculation with HA followed by PM. Spores concentrations of AM fungi increased significantly with AM inoculation alone and with FYM, PM and HA. Maximum spores numbers of 50 in 20 g soil were recorded by the inoculation of AM fungi alone and with HA. (author)

  5. Arsenite-oxidizing bacteria exhibiting plant growth promoting traits isolated from the rhizosphere of Oryza sativa L.: Implications for mitigation of arsenic contamination in paddies.

    Science.gov (United States)

    Das, Suvendu; Jean, Jiin-Shuh; Chou, Mon-Lin; Rathod, Jagat; Liu, Chia-Chuan

    2016-01-25

    Arsenite-oxidizing bacteria exhibiting plant growth promoting (PGP) traits can have the advantages of reducing As-uptake by rice and promoting plant growth in As-stressed soil. A gram-positive bacterium Bacillus flexus ASO-6 resistant to high levels of As (32 and 280 mM for arsenite and arsenate, respectively) and exhibiting elevated rates of As(III) oxidation (Vmax=1.34 μM min(-1) 10(-7) cell) was isolated from rhizosphere of rice. The presence of aoxB gene and exhibition of As(III)-oxidase enzyme activity of this strain was observed. The ability of the strain to produce siderophore, IAA, ACC-deaminase and to solubilize phosphate was verified. The rice seed treated with the strain exhibited significantly improved seed germination and seedling vigor compared with the un-inoculated seeds. The bacterial inoculation significantly increased root biomass, straw yield, grain yield, chlorophyll and carotenoid in the rice plant. Moreover, As uptake from root to shoot and As accumulation in straw and grain decreased significantly as a result of the bacterial inoculation. Noteworthy, the inoculation effect is more prominent in non-flooded soil than it is in flooded soil. Owing to its wide action spectrum, this As(III)-oxidizing PGPB could serve as a potential bio-inoculant for mitigation of As in paddies and sustainable rice production in As-contaminated areas. PMID:26448489

  6. Role of microbial inoculation and chitosan in phytoextraction of Cu, Zn, Pb and Cd by Elsholtzia splendens - a field case

    Energy Technology Data Exchange (ETDEWEB)

    Wang Fayuan [Agricultural College, Henan University of Science and Technology, 70 Tianjin Road, Luoyang, Henan Province 471003 (China) and Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province 210008 (China)]. E-mail: wfy1975@163.com; Lin Xiangui [Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province 210008 (China); Yin Rui [Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province 210008 (China)

    2007-05-15

    A field experiment was carried out to study the effect of microbial inoculation on heavy metal phytoextraction by Elsholtzia splendens and whether chitosan could have a synergistic effect with the microbial inocula. The microbial inocula consisted of a consortium of arbuscular mycorrhizal fungi and two Penicillium fungi. Three treatments were included: the control, inoculation with microbial inocula, and the inoculation combined with chitosan. Microbial inoculation increased plant biomass especially shoot dry weight, enhanced shoot Cu, Zn and Pb concentrations but did not affect Cd, leading to higher shoot Cu, Zn, Pb and Cd uptake. Compared with microbial inoculation alone, chitosan application did not affect plant growth but increased shoot Zn, Pb and Cd concentrations except Cu, which led to higher phytoextraction efficiencies and partitioning to shoots of Zn, Pb and Cd. These results indicated synergistic effects between microbial inocula and chitosan on Zn, Pb and Cd phytoextraction. - Co-application of microbial inocula and chitosan enhanced heavy metal phytoextraction by E. splendens.

  7. Role of microbial inoculation and chitosan in phytoextraction of Cu, Zn, Pb and Cd by Elsholtzia splendens - a field case

    International Nuclear Information System (INIS)

    A field experiment was carried out to study the effect of microbial inoculation on heavy metal phytoextraction by Elsholtzia splendens and whether chitosan could have a synergistic effect with the microbial inocula. The microbial inocula consisted of a consortium of arbuscular mycorrhizal fungi and two Penicillium fungi. Three treatments were included: the control, inoculation with microbial inocula, and the inoculation combined with chitosan. Microbial inoculation increased plant biomass especially shoot dry weight, enhanced shoot Cu, Zn and Pb concentrations but did not affect Cd, leading to higher shoot Cu, Zn, Pb and Cd uptake. Compared with microbial inoculation alone, chitosan application did not affect plant growth but increased shoot Zn, Pb and Cd concentrations except Cu, which led to higher phytoextraction efficiencies and partitioning to shoots of Zn, Pb and Cd. These results indicated synergistic effects between microbial inocula and chitosan on Zn, Pb and Cd phytoextraction. - Co-application of microbial inocula and chitosan enhanced heavy metal phytoextraction by E. splendens

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

    Directory of Open Access Journals (Sweden)

    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.

  9. A plant natriuretic peptide-like gene in the bacterial pathogen Xanthomonas axonopodis may induce hyper-hydration in the plant host: a hypothesis of molecular mimicry

    OpenAIRE

    Sayed Muhammed; Seoighe Cathal; Nembaware Victoria; Gehring Chris

    2004-01-01

    Abstract Background Plant natriuretic peptides (PNPs) are systemically mobile molecules that regulate homeostasis at nanomolar concentrations. PNPs are up-regulated under conditions of osmotic stress and PNP-dependent processes include changes in ion transport and increases of H2O uptake into protoplasts and whole tissue. Presentation of the hypothesis The bacterial citrus pathogen Xanthomonas axonopodis pv. Citri str. 306 contains a gene encoding a PNP-like protein. We hypothesise that this ...

  10. Common sequence motifs coding for higher-plant and prokaryotic O-acetylserine (thiol)-lyases: bacterial origin of a chloroplast transit peptide?

    Science.gov (United States)

    Rolland, N; Job, D; Douce, R

    1993-08-01

    A comparison of the amino acid sequence of O-acetylserine (thiol)-lyase (EC 4.2.99.8) from Escherichia coli and the isoforms of this enzyme found in the cytosolic and chloroplastic compartments of spinach (Spinacia oleracea) leaf cells allows the essential lysine residue involved in the binding of the pyridoxal 5'-phosphate cofactor to be identified. The results of further sequence comparison of cDNAs coding for these proteins are discussed in the frame of the endosymbiotic theory of chloroplast evolution. The results are compatible with a mechanism in which the chloroplast enzyme originated from the cytosolic enzyme and both plant genes originated from a common prokaryotic ancestor. The comparison also suggests that the 5'-non-coding sequence of the bacterial gene was transferred to the plant cell nucleus and that it has been used to create the N-terminal portions of both plant enzymes, and possibly the transit peptide of the chloroplast enzyme. PMID:7916619

  11. Assessment of the relevance of the antibiotic 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine from Pantoea agglomerans biological control strains against bacterial plant pathogens.

    Science.gov (United States)

    Sammer, Ulrike F; Reiher, Katharina; Spiteller, Dieter; Wensing, Annette; Völksch, Beate

    2012-12-01

    The epiphyte Pantoea agglomerans 48b/90 (Pa48b) is a promising biocontrol strain against economically important bacterial pathogens such as Erwinia amylovora. Strain Pa48b produces the broad-spectrum antibiotic 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine (APV) in a temperature-dependent manner. An APV-negative mutant still suppressed the E. amylovora population and fire blight disease symptoms in apple blossom experiments under greenhouse conditions, but was inferior to the Pa48b wild-type indicating the influence of APV in the antagonism. In plant experiments with the soybean pathogen Pseudomonas syringae pv. glycinea both, Pa48b and the APV-negative mutant, successfully suppressed the pathogen. Our results demonstrate that the P. agglomerans strain Pa48b is an efficient biocontrol organism against plant pathogens, and we prove its ability for fast colonization of plant surfaces over a wide temperature range. PMID:23233458

  12. Induced mutation for bacterial blight resistance in mulberry

    International Nuclear Information System (INIS)

    Buds of mulberry varieties Phai, Noi and SK2502 were irradiated by gamma radiation and then cultured on the Murashige and Skoog medium containing 1.0 mg/l of BA and Casein hydrolysate 1g/l. After proliferation of shoots, they were transferred to the rooting medium (MS + NAA 0.2 mg/l + IBA 0.2 mg/l). Plantlets of mulberry var. Noi were transplanted to soil in greenhouse for screening for bacterial blight disease resistance. All plants showed symptoms of disease. In vitro inoculation of the pathogen, Pseudomonas syringae p.v. mori, on plantlets of the mulberry var. Noi and Phai was conducted. All plants showed symptoms of the disease and died. In vitro screening will be continued with much larger populations in order to select the resistance traits. (author). 4 refs, 4 tabs

  13. Field performance of Alnus cordata Loisel (Italian alder) inoculated with Frankia and VA-mycorrhizal strains in mine-spoil afforestation plots

    Energy Technology Data Exchange (ETDEWEB)

    Lumini, E.; Bosco, M.; Puppi, G.; Isopi, R.; Frattegiani, M.; Burseti, E.; Favili, F.

    1994-05-01

    Mixed stands of {ital Alnus cordata}, {ital Eleagnus} spp. and broad leaf timber trees have been successfully used for reclamation of mine spoils in surface mined areas of central Italy. Trials showed that the use of mycorrhizal planting stock may improve the establishment of plants on mine spoils. Alder seeds were sown in pots filled with peat moss and lignite mine spoils and Fungal strains {ital Glomus mosscae} and {ital G. fasciculatum} were inoculated into the pots. A Frankia strain isolated from {ital A. cordata} was also tested. Plants were then outplanted after measuring shoot height and collar diameter. The planting was done in mid-January among commercial trees ({ital Quercus robur}, {ital Fraxinus oxyphilla}, and {ital Prunus avium}). Plants became highly nodulated in the pots. Mycorrhizal infection was about 30% on inoculate plants but did not occur on uninoculated plants. Aboveground biomass at out-planting was significantly greater in the Frankia inoculated plants. There was generally more N in plant leaves in the inoculate plants than in the uninoculated ones. Plant survival in the field after one winter was 83% on average. One year after planting, the inoculated plants were significantly bigger as were the Frankia inoculated plants. The combination of Frankia and Glomus was very effective (contrary to other studies).

  14. Effect of Azolla Inoculation on the Contribution of Urea-N Fertilizer in Lowland Rice Culture

    International Nuclear Information System (INIS)

    Two experiments (dry and wet seasons) have been conducted to study effect of Azolla inoculated in lowland rice culture. Five treatments combination of urea and Azolla tested were: N-0, N-0+Az, N-45+Az, N-90+Az, and N-90. Experiments were designed with completely randomized design (CRD) and each treatment was replicated 4 times. 15N-labelled urea was used in this experiment to determine N-derived from fertilizer. Results of this experiments showed that planting season did not influenced production of grain, total-N percentage, and total-N uptake of the plant. Azolla inoculation was able to increase dry matter production, percentage of total-N, and plant total-N uptake up to 36 %. The fertilizer use efficiencies were increased 16 % in dry season and 23 % in wet season respectively. This condition expressed that Azolla inoculation in lowland rice could present N-logg through vaporization and water current. (author)

  15. Effect of combined microbes on plant tolerance to Zn-Pb contaminations.

    Science.gov (United States)

    Ogar, Anna; Sobczyk, Łukasz; Turnau, Katarzyna

    2015-12-01

    The presence and composition of soil microbial communities has been shown to have a large impact on plant-plant interactions and consequently plant diversity and composition. The goal of the present study was to evaluate impact of arbuscular mycorrhizal fungi (AMF) and nitrogen-fixing bacteria, which constitutes an essential link between the soil and the plant's roots. A greenhouse pot experiment was conducted to evaluate the feasibility of using selected microbes to improve Hieracium pilosella and Medicago sativa growth on Zn-Pb-rich site. Results of studies revealed that biomass, the dry mass of shoots and roots, increased significantly when plants were inoculated with mycorrhizal fungi and nitrogen-fixing bacteria. The addition of Azospirillum sp. and Nostoc edaphicum without mycorrhiza suppressed plant growth. Single bacterial inoculation alone does not have a positive effect on M. sativa growth, while co-inoculation with AMF improved plant growth. Plant vitality (expressed by the performance index) was improved by the addition of microbes. However, our results indicated that even dry heat sterilization of the substratum created imbalanced relationships between soil-plant and plants and associated microorganisms. The studies indicated that AMF and N2-fixers can improve revegetation of heavy metal-rich industrial sites, if the selection of interacting symbionts is properly conducted. PMID:26250813

  16. Nodulation, Symbiotic Growth and Yield of Vegetable Soybean Inoculated with Photorhizobium and Bradyrhizobium Zulkifli

    Directory of Open Access Journals (Sweden)

    H. Shamsuddin

    1999-01-01

    Full Text Available A pot experiment with vegetable soybean (Glycine max L. AGS190 inoculated with Photorhizobium was conducted with the following five treatments: three inoculation treatments with Photorhizobium (-N+Br and a combination of both inocula (-N + Pr + Br, and two uninoculated nitrogen treatments, with and without inorganic nitrogen (+N-I, -N-I. The plants were harvested for symbiotic growth and yield after 42 and 65 days, respectively. The results showed that Photorhizobium was able to nodulate vegetable soybean; the nodules formed were larger (74mg/nodule than the other two inoculation treatments involving Bradyrhizobium (32 and 35mg/nodule. The analysis N-solutes in xylem exudates indicated that nodules formed by Photorhizobium have high N2 fixing activity (98.3 %. However, a low concentration (0.19 % of reducing sugar in the nodule tissues compared to the Bradyrhizobium and combined inoculum treatments (1.72 and 1.92 % respectively lowered the total amount of N2 fixed; consequently, the relatively lower leaf N concentration (2.73 % compared to control treatment with inorganic nitrogen (+N-I (3.12%. A mixed inoculum of Photorhizobium and Bradyrhizobium showed a synergistic effect on the leaf N concentration (3.64 % and pod yield (4.21 g/plant compared to a single inoculation with Bradyrhizobium (3.31 %, 4.05 g/plant. Photorhizobium inoculation alone produced a significant reduction in pod yield (3.42g/plant which corresponded directly to the lower leaf N concentration (2.73 %. This stud showed that Photorhizobium can nodulate vegetable soybean but have no positive effect in supplying photosynthate to the nodules and produced lower leaf N concentration and pod yield compared to Bradyrhizobium inoculation. co-inoculation with Photorhizobium and Bradyrhizobium produced a synergistic effect on the leaf N concentration and pod yield.

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

    International Nuclear Information System (INIS)

    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

  18. Influence of Rhizobacterial Inoculation on Growth of the Sweetpotato Cultivar

    Directory of Open Access Journals (Sweden)

    Y. Farzana

    2005-01-01

    Full Text Available Sweetpotato (Ipomoea batatas L. is the most important of local tuber crops in Malaysia. It is usually planted on marginal soils such as peat and sandy soils. Malaysian’s are consumed a lot of sweetpotatoes and its production requires high fertilizer input, which can lead to increased production cost and environment problems. The use of biofertilizer and bioenhancer such as N2 (nitrogen fixing bacteria and beneficial microorganism can reduce chemical fertilizer applications and consequently lower production cost. The pot experiment was conducted to determine the influence of rhizobacterial isolates on the response of sweetpotato plant growth. A total of five rhizobacterial isolates capable of producing indole-3-acetic acid (IAA were used. Four of the isolates were collected from sweetpotato rhizosphere and one isolate was imported. Cuttings of sweetpotato cultivars melaka and oren were planted in plastic pots containing alluvium soil. Cultures of the rhizobacterial isolates were inoculated at planting time, two and four weeks after planting. Plants were harvested 60 days after planting. The results showed that, three of isolates significantly increased the plant growth and the N, P, K, Ca and Mg uptake of sweetpotato cultivar.

  19. The Influence of Gamma Irradiation on the Bacterial Growth and the Concentration of Macro nutrient Plant Elements (N,P,K) in The Sludge

    International Nuclear Information System (INIS)

    The investigation of the gamma irradiation influence for bacterial growth and macro-nutrient plant element in the sludge has been done. The objective of the research is to study the gamma irradiation influence on bacterial growth and macro-nutrient plant element concentration; after that, can be determine the effective dose for killing pathogenic bacteria, while the other kind of bacteria such as the decomposer has been survived. The sludge samples was collected from the vicinity of Surabaya such as Sukolilo for sewage, PT SIER Rungkut for in