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Aims@#Plant growth-promoting bacteria are the key components of a biofertilizer. This study was aimed to isolate and identify the predominant bacteria found in a foliar biofertilizer and characterizes the potential of the bacterial isolates as plant growth promoters.@*Methodology and results@#Potential bacteria with plant growth-promoting activities were isolated from a foliar biofertilizer on HiCrome™ Bacillus agar and Nutrient agar. Bacteria with unique colonial morphology were selected and categorized by Gram’s differential staining. Subsequently, the bacterial isolates were being further characterized for plant growth-promoting potentials, such as the production of indole acetic acid (IAA), 1-aminocyclopropane-1-carboxylate (ACC) deaminase and siderophore; as well as the ability of nitrogen fixation and phosphate/potassium solubilization. Based on the characterized traits, three bacterial isolates, namely M17, M22 and M52 showed great potential for being a plant growth promoter. Based on their 16S rRNA gene sequence analysis, M17, M22 and M52 were identified as Leclercia adecarboxylata, Margalitia shackletonii and Lysinibacillus pakistanensis, respectively.@*Conclusion, significance and impact of study@#Bacterial isolates exhibiting plant growth-promoting activities were successfully isolated from a biofertilizer and identified in this study. This finding provides an insight into the potential bacteria of a foliar fertilizer that may promote plant growth. Identification of these plant-growth promoters may help the scientists and agrochemical manufacturers to determine and disclose the key microorganisms of their biofertilizers, thereby contributing to the improvement of biofertilizers and promoting them as reliable alternatives to chemical fertilizers.
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Endophytic bacteria Bacillus safensis RS95 and Pseudomonas hibiscicola RS121 were evaluated for their ability to promote the growth of rice seedlings and produce indole-acetic acid (IAA) and siderophores and to solubilize phosphates. 'Guri' rice seeds were immersed in bacterial endophyte cell suspensions (separated and two-strain mixed), as well as in Escherichia coli DH5α, phosphate-buffered saline (PBS) and water treatments (negative controls). Seeds were sown on agar-water in Petri plates placed vertically at an angle of 65°. The ability of plant growth-promoting endophytic bacteria (PGPEB) to produce IAA and siderophores was determined by Salkowski colorimetric and chrome azurol S (CAS) assays, respectively. Mineral phosphate solubilization activity was calculated by inoculating the endophytes onto medium containing insoluble phosphate. PGPEB showed a positive effect on the growth of rice seedlings, causing a mean growth of shoots and primary-roots of 60 and 67%, respectively. Bacterial strains also showed positive traits for IAA and siderophore production, as well as phosphate-solubilization activity
Subject(s)
Pseudomonas , Oryza/growth & development , Bacillus , Siderophores , Endophytes , Indoleacetic Acids/analysis , PhosphatesABSTRACT
ABSTRACT In the present study, 62 endophytic bacterial strains of cedar seeds (Cedrela odorata L.), collected in the municipalities of Huehuetán, Motozintla, and Pijijiapan in the state of Chiapas, Mexico were isolated. The goal was to identify characteristics of biotechnological interest such as biocontrol, promotion ofplant growth, and growth in aromatic compounds. The strains were identified by the partial sequence of the 16S ribosomal gene as belonging to the Bacillus genus. The biocontrol capacity of phytopathogenic fungi, production of indoleacetic acid (IAA), solubilization of phosphate, and growth in xenobiotic compounds (phenanthrene, benzene, anthracene, or phenol) were detected in 26 strains of the 62 isolates. 21 % of the strains inhibited the mycelial growth of Alternaria solani and Fusarium sp., and 13 % of the Phytophthora capsici oomycete. IAA production was detected in 24 isolates, phosphate solubilizing activity was identified in 18 isolates, while the ability to grow in the presence of phenanthrene and benzene was found in 26 isolates; 24 isolates grew in the presence of anthracene and only two isolates grew in phenol as the only carbon sources. This is the first report of the isolation and identification of endophytic bacteria from cedar seeds, where biotechnological characteristics were detected for biological control, promotion of plant growth, and growth in the presence of xenobiotic compounds.
RESUMEN En el presente estudio se aislaron 62 cepas bacterianas endófitas de semillas de cedro (Cedrela odorata L.) colectadas en los municipios de Huehuetán, Motozintla y Pijijiapan en el estado de Chiapas, México, con el objetivo de identificar características de interés biotecnológicas como biocontrol, promoción del crecimiento vegetal y crecimiento en compuestos aromáticos. Las cepas se identificaron por la secuencia parcial del gen 16S ribosomal como pertenecientes al género Bacillus. En 26 cepas de las 62 aisladas se detectaron la capacidad de biocontrol de hongos fitopatógenos, la producción de ácido indolacético (AIA), la solubilización de fosfato y el crecimiento en compuestos xenobióticos (fenantreno, benceno, antraceno o fenol). El 21 % de las cepas inhibió el crecimiento miceliar de Alternaria solani y Fusarium sp., y el 13 % del oomiceto Phytophthora capsici. La producción de ácido indolacético se detectó en 24 aislados y la actividad solubilizadora de fosfato se encontró en 18 aislados, mientras que la capacidad de crecer en presencia de fenantreno y benceno se manifestó en 26 aislados (24 aislados crecieron en presencia de antraceno y solo dos aislados crecieron en fenol como únicas fuentes de carbono). Es importante mencionar que este es el primer reporte del aislamiento e identificación de bacterias endófitas de semillas de cedro, en el que se detectaron características biotecnológicas para el control biológico, la promoción del crecimiento vegetal y el crecimiento en presencia de compuestos xenobióticos.
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Objective: To study the effect of the inoculation time of arbuscular mycorrhizal (AM) fungi on endogenous hormone content in Paris polyphylla var. yunnanensis seedlings. Methods: The indoor pot test was applied. The seeds, one-year-old seedlings, and two-year-old seedlings of P. polyphylla var. yunnanensis were inoculated by different mixed AM fungi and cultivated in the sterilized soil matrix respectively. The contents of endogenous hormone zeatin riboside (ZR), gibberellin (GA), indole acetic acid (IAA) and abscisic acid (ABA) were determined by HPLC. Results: The results showed that the endogenous hormone (ZR, GA, IAA and ABA) contents in rhizome and fibrous roots of P. polyphylla var. yunnanensis from different regions or different time inoculated by mixed AM fungi were various. As a whole, the contents of endogenous hormone ZR and GA increased obviously in the rhizome and fibrous roots of the wild and cultivated P. polyphylla var. yunnanensis compared with the control group (CK), while the content of ABA reduced. The IAA/ABA value, GA/ABA value and ZR/ABA value increased obviously in the rhizome and fibrous roots of P. polyphylla var. yunnanensis. Conclusion: The one-year-old of P. polyphylla var. yunnanensis inoculated with S2 and S6 mixed AM fungi showed the best comprehensive effect for promoting growth of the rhizome and fibrous roots of P. polyphylla var. yunnanensis seedlings.
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Objective::To clone the complementary deoxyribonucleic acid (cDNA) of auxin/indole acetic acid protein (Aux/IAA) from Glycyrrhiza glabra (GgARPI) and analyze its sequence by bioinformatics. Method::RNA was extracted from fresh root of G. glabra, the cDNA sequence of GgARPI gene was cloned by reverse transcription polymerase chain reaction (RT-PCR), then sequencing and bioinformatic analysis were performed. Result::The GgARPI cDNA sequence with the full length of 686 bp was obtained from G. glabra. The full open reading frame (ORF) was 585 bp, encoding 194 amino acid residues. The bioinformatic analysis showed that the protein coded by GgARPI was a stable hydrophilic protein, with a relative molecular weight of 21.95 kDa and isoelectric point of 6.85.It contained no signal peptides or transmembrane domain. Its secondary structure mainly consisted of random coil. An Aux/IAA superfamily was included in the conversed domain. Homology analysis indicated that it had a close evolutionary relationship with leguminous plants, and a distant evolutionary relationship with monocotyledon, such as Setaria italica. Conclusion::GgARPI cDNA sequence is successfully cloned from G. glabra for the first time, which will lay a foundation for studying the function of GgARPI and explaining the molecular regulatory mechanism of biosynthesis of glycyrrhizic acid in G. glabra.
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Abstract Bacterial endophytes are considered to have a beneficial effect on host plants, improving their growth by different mechanisms. The objective of this study was to investigate the capacity of four endophytic Bacillus strains to solubilize iron phosphate (Fe-P), produce siderophores and indole-acetic acid (IAA) in vitro, and to evaluate their plant growth promotion ability in greenhouse conditions by inoculation into pearl millet cultivated in a P-deficient soils without P fertilization, with Araxá rock phosphate or soluble triple superphosphate. All strains solubilized Fe-P and three of them produced carboxylate-type siderophores and high levels of IAA in the presence of tryptophan. Positive effect of inoculation of some of these strains on shoot and root dry weight and the N P K content of plants cultivated in soil with no P fertilization might result from the synergistic combination of multiple plant growth promoting (PGP) traits. Specifically, while B1923 enhanced shoot and root dry weight and root N P content of plants cultivated with no P added, B2084 and B2088 strains showed positive performance on biomass production and accumulation of N P K in the shoot, indicating that they have higher potential to be microbial biofertilizer candidates for commercial applications in the absence of fertilization.
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Abstract Bacterial endophytes are considered to have a beneficial effect on host plants, improving their growth by different mechanisms. The objective of this study was to investigate the capacity of four endophytic Bacillus strains to solubilize iron phosphate (Fe-P), produce siderophores and indole-acetic acid (IAA) in vitro, and to evaluate their plant growth promotion ability in greenhouse conditions by inoculation into pearl millet cultivated in a P-deficient soils without P fertilization, with Araxá rock phosphate or soluble triple superphosphate. All strains solubilized Fe-P and three of them produced carboxylate-type siderophores and high levels of IAA in the presence of tryptophan. Positive effect of inoculation of some of these strains on shoot and root dry weight and the N P K content of plants cultivated in soil with no P fertilization might result from the synergistic combination of multiple plant growth promoting (PGP) traits. Specifically, while B1923 enhanced shoot and root dry weight and root N P content of plants cultivated with no P added, B2084 and B2088 strains showed positive performance on biomass production and accumulation of N P K in the shoot, indicating that they have higher potential to be microbial biofertilizer candidates for commercial applications in the absence of fertilization.
Subject(s)
Bacillus/metabolism , Food/metabolism , Pennisetum/growth & development , Pennisetum/microbiology , Endophytes/metabolism , Indoleacetic Acids/metabolism , Phosphates/analysis , Phosphates/metabolism , Bacillus/genetics , Siderophores/metabolism , Plant Roots/growth & development , Plant Roots/metabolism , Plant Roots/microbiology , Pennisetum/metabolism , Endophytes/genetics , Iron/metabolismABSTRACT
ABSTRACT Rhizobium-legume symbioses play relevant roles in agriculture but have not been well studied in Ecuador. The aim of this study was to characterize the genetic and phenotypic diversity of Rhizobium isolates associated with Phaseolus vulgaris from southern Ecuador. Morpho-cultural characterization, biochemical tests and physiological analyses were conducted to authenticate and determine the diversity of bacteria Rhizobium-like isolates. The genetic diversity of the isolates was determined by molecular techniques, which consisted of bacteria DNA extraction and amplification and sequencing of the 16S rRNA gene. The nodulation parameters and nitrogen fixation for P. vulgaris under greenhouse conditions were also assessed to determine the phenotypic diversity among isolates. Furthermore, bacteria indole-acetic-acid production was evaluated by the colorimetric method. Morpho-cultural and biochemical characteristic assessments demonstrated that Rhizobium-like bacteria was associated with the P. vulgaris nodules. The diversity among the isolates, as determined by physiological analyses, revealed the potential of several isolates to grow at different pH values, salinity conditions and temperatures. Partial sequencing of the 16S rRNA gene identified the Rhizobium genus in every sampling site. From a total of 20 aligned sequences, nine species of Rhizobium were identified. Nodule formation and biomass, as well as nitrogen fixation, showed an increase in plant phenotypic parameters, which could be influenced by IAA production, especially for the strains R. mesoamericanum NAM1 and R. leguminosarum bv. viciae COL6. These results demonstrated the efficiency of native symbiotic diazotrophic strains inoculants for legume production. This work can serve as the basis for additional studies of native Rhizobium strains and to help spread the use of biofertilizers in Ecuadorian fields.
RESUMO A simbiose Rhizobium-leguminosa desempenha um relevante papel na agricultura, entretanto não tem recebido suficiente atenção de estudos científicos no Equador. O objetivo deste artigo foi caracterizar a diversidade genética e fenotípica de isolados de Rhizobium associados com Phaseolus vulgaris do sul do Equador. A caracterização morfo-cultural, testes bioquímicos e análises fisiológicas foram realizados para autenticar e determinar a diversidade de isolados de bactérias Rhizobium. A diversidade genética foi determinada por por técnicas moleculares consistindo na extração de DNA genômico bacteriano, amplificação e sequenciamento parcial do gene 16SrRNA; e parâmetros de nodulação e fixação de nitrogênio de P. vulgaris sobre condições de estufa foram testados para determinar a diversidade fenotípica entre os isolados. Além disso, a produção de ácido indolacético foi avaliada por um método colorimétrico. A análise fisiológica da diversidade entre os isolados revelou o potencial de crescimento de diversos isolados em diferentes níveis de pH, salinidade e temperatura. O sequenciamento parcial do gene 16S rRNA mostrou o gênero Rhizobium em todas os locais de amostragem. De um total de 20 sequências alinhadas, 9 espécies de Rhizobium foram identificadas. A formação de nódulos e biomassa, bem como a fixação de nitrogênio mostraram um aumento nos parâmetros fenotípicos das plantas, os quais devem ser influenciados pela produção de IAA, especialmente pelas cepas R. mesoamericanum NAM1 e R. leguminosarum bv. viciae COL6. Estes resultados demonstram a eficiência de cepas diazotróficas simbióticas nativas para produção de inoculantes para leguminosas e fornece informações valiosas e uteis para a agricultura sustentável equatoriana. Neste sentido, este trabalho deve ser um elemento essencial para a realização de futuras pesquisas aplicadas relacionadas a cepas Rhizobium nativas e espalhar o uso de biofertizantes em campos equatorianos.
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RESUMEN Con el propósito de evaluar el efecto de tres concentraciones de ácidos húmicos (AH) 1, 10, 100 mg/L contra una concentración de ácido indol acético (AIA), sobre la producción de biomasa, pigmentos, proteínas, carbohidratos y lípidos de A. platensis; se realizaron cultivos en discontinuo en medio Zarrouk 25% suplementados con AH y AIA, bajo condiciones de aireación constante y fotoperiodos de 12:12 horas, durante 30 días. Se encontró que la producción máxima de biomasa fue mayor en el cultivo suplementado con 10 mg/L de AH, comparado con el control y los cultivos suplementados con AIA. De la misma manera fue observado en este tratamiento la producción más alta de pigmentos, proteínas y carbohidratos. Por tanto, se logró incrementar el crecimiento y la producción de metabolitos de A. platensis, lo cual permite observar el uso potencial de estas sustancias como estimulantes biológicos orgánicos.
ABSTRACT The purpose of this research was to evaluate the effect of three concentrations of humic acids (HA) 1, 10, 100 mg/L against a concentration of indole acetic acid (IAA) on production of biomass, pigments, proteins, carbohydrates and lipids of A. platensis. Cultures discontinuous in Zarrouk 25% medium supplemented with HA and IAA under conditions of aeration constant and photoperiod from 12:12 hours, during 30 days were made. It was found that the maximum biomass production was higher in the culture supplemented with 10 mg / L of AH, compared to the control and cultures supplemented with AIA. In the same way the highest production of pigments, proteins and carbohydrates were observed in this treatment. Therefore, the growth and production of metabolites of A. platensis was increased, which makes it possible to observe the potential use of these substances as organic biological stimulants.
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Azotobacter strains were isolated by serial dilution method and colonies were viscous, smooth, glistening, and brown to black colour on Jenson’s N-free agar. Morphological and biochemical tests showed characteristic features of Azotobacter. Further, molecular analyses revealed the presence of different Azotobacter species viz., A. armeniacus, A. chroococcum, A. salinestris, A. tropicalis and A. vinelandii. The isolates were tested for their ability of nitrogen fixation, indole acetic acid (IAA), gibberllic acid production and phosphate solubilization. Four isolates (GVT-1, GVT-2 KOP-11 and SND-4) were efficient in fixation of highest amount of N2 (29.21 μg NmL-1day-1), produced IAA (25.50 µg mL-1), gibberllic acid (17.25 μg 25 mL-1) and formed larger P solubilizing zone (13.4 mm). Some of the Azotobacter strains were produced siderophores, hydrogen cyanide and were positive for ammonia production with respect to antifungal activity of Azotobacter was tested with dual culture method and A. tropicalis inhibited the growth of Fusarium, Aspergillus and Alternaria species. Azotobacter isolates were tested against salt (0-10%), temperature (4-55ºC), pH (5.0-10) and insecticide chloropyrifos (0-3%) tolerance study. Among them, A. chroococcum was found tolerant to a maximum of 6% NaCl with a temperature of 35-45ºC and to a pH up to 8. All the 4 strains showed effective growth against 3% chloropyrifos concentration. The studies revealed that the Azotobacter strains not only produced plant growth promoting substances but are also tolerant to abiotic stresses such as temperature, pH and insecticides.
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Melatonin is an environmentally friendly-molecule with a potent free radical scavenger and antioxidant capacity. Two pot experiments were conducted during two successive winter seasons (2011/2012 and 2012/2013) at the wire-house of the National Research Centre, Dokki, Cairo, Egypt to study the potentiality of melatonin (100 mM and 500 mM) in alleviating the harmful effect of diluted seawater at a relatively low and high concentrations (3.85 dS/m and 7.69 dS/m, respectively) on the performance of faba bean plants. The results revealed that irrigation of faba bean plants with diluted seawater reduced growth parameters (plant height, leaves number/plant, fresh and dry weights of plant), relative water content (RWC), photosynthetic pigments (chlorophylls a, b and carotenoids), indole acetic acid, total carbohydrate, K+,Ca+2, as well as the ratios of K+/Na+ and Ca+2/Na+. Thiswasaccompanied by significant increases in phenolic content, compatible solutes (total soluble carbohydrate, free amino acids, proline), Na+ and Cl- relative to the control plants (untreated plants). On the other hand, melatonin treatments improved growth parameters, RWC, photosynthetic pigments, total carbohydrate, total phenolic content, indole acetic acid, K+,Ca+2 as well as K+/Na+ and Ca+2/Na+ ratios, either in the plants irrigated with tap water or with diluted seawater, as compared with corresponding controls. Meanwhile, melatonin treatments reduced the levels of compatible solutes, as well as Na+ and Cl- contents, relative to those of corresponding controls. Salinity stress and/ or melatonin treatments induced the production of new protein bands that did not occur in the control plants. Melatonin at 500 mM had a more pronounced effect in alleviating the adverse effects of the two salinity levels under study on the performance of faba bean plants than 100 mM melatonin.
La melatonina es una molécula ambientalmente amigable con una potente capacidad antioxidante y de trampa de radicales libres. Dos experimentos en materas fueron realizados en dos inviernos consecutivos (2011/2012 y 2012/2013) en instalaciones del Centro Nacional de Investigaciones, Dokki, Cairo, Egipto, para estudiar el potencial de la melatonina (100 mM and 500 mM) para disminuir los efectos nocivos del agua de mar diluida a concentraciones relativamente bajas y altas (3,85 dS/m and 7,69 dS/m, respectivamente). Los resultados mostraron que la irrigación de plantas de haba con agua de mar diluida reduce los parámetros de crecimiento (altura de la planta, número de hojas/planta, peso fresco y seco de la planta), el contenido relativo de agua (RWC), los pigmentos fotosintéticos (clorofilas a, b y carotenoides), el ácido indo lacético, los carbohidratos totales, K+, Ca+2, al igual que las relaciones K+/Na+ y Ca2+/Na+. Esto fue acompañado por un incremento significativo en el contenido de fenoles, solutos compatibles (carbohidratos solubles totales, aminoácidos libres, prolina), Na+ y Cl- en comparación con las plantas control (plantas no tratadas). De otro lado, los tratamientos con melatonina mejoraron los parámetros de crecimiento, RWC, los pigmentos fotosintéticos, carbohidratos totales, contenido fenólico total, ácido indo acético, K+,Ca+2 al igual que las relaciones K+/Na+ y Ca+2/Na+ , tanto en las plantas irrigadas con agua dulce de la llave como en las irrigadas con agua de mar diluida en comparación con los controles correspondientes. De otro lado, los tratamientos con melatonina redujeron los niveles de solutos compatibles, al igual que los contenidos de Na+ y Cl-, en comparación con los controles. El estrés por salinidad y/o los tratamientos con melatonina indujeron la producción de nuevas bandas de proteínas que no estuvieron presentes en las plantas control. El tratamiento de melatonina 500 mM tuvo un efecto más pronunciado que el tratamiento de 100 mM en disminuir los efectos adversos de los dos niveles de salinidad estudiados sobre el comportamiento de las plantas de haba.
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Recently, plant growth hormones have been widely used in green houses and the consumptions of agriculture food products have markedly increased; however their toxicological aspects are still unclear. The aim of the present study is to illustrate the toxicities of plant growth hormones; gibberellic (GA3) and indole acetic acid (IAA) on ocular tissues of pregnant Wistar albino rats and their offsprings. Intra-gastric administration of either GA3 or IAA (100 mg/kg body weight) to mother rats were carried out for one month prior to conception as well as throughout gestation period (n=20). The control received saline-free organochemical compounds (n=10). At parturition, mother rats and their offsprings were sacrificed by light anesthesia, and their ocular regions were separated and investigated for light and transmission electron microscopy, immunochemical staining of Caspase-3, Bcl-2 and p53 and assessments of antioxidant enzymes and DNA fragmentation. Maternal administration of either GA3 or IAA was found to develop cataractous lenses to about 6% (3/20) in GA3-treatment and 4% (2/20) in IAA-treatment. The applied organochemical compounds developed retinopathy in mother rats and their offsprings. These were characterized by apparent damage of ganglion and nuclear cells. In mothers, the photoreceptor’s outer segment showed spotty dissolution of their stacked membranes while in offsprings, there was still lack of differentiation. The retinal tissue showed discrete positive immunostaining foci with P53, Pcl2 and caspase-3, especially in ganglion and nuclear cells compared with control. The antioxidant enzymes' catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR) and peroxidase (GPx) showed apparent depletion and vice versa for malondialdhyde (MDA) and hydrogen peroxide (H2O2), the markers of cell death. DNA fragmentation was markedly detected. Finally, it was concluded that maternal administration of GA3 and IAA led to the development of retinopathy and development of cataractous lenses parallel to the increase of immunostaining of caspase-3, Pcl2 and P53 and decrease of the endogenous antioxidant system and increase of DNA damage.
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germination of S. emarginatus in vitro cotyledon explants in BAP/Kn/TDZ (1.0-3.0 mg/L) supplemented MS medium and (2) in plant treatment with BAP/Kn/TDZ (3.0 mg/ L) in combination of 1AA (0.5 mg/L) of the cotyledon explants of plants and maintained under sterile conditions. While the former method resulted in as many as (7.5±8.6 shoot buds) from the cotyledonary explants within four weeks, the latter yielded on average approximately 8 shoot buds from each treated node in eight weeks. The cytokinin treatment in plant consisted of placing sterile filter paper moistened with sterile distilled water over the node and adding different concentrations of 6- benzylaminopurine. The best results for shoot bud regeneration were obtained with cotyledons, when cultured in the presence of (0.5 mg/L) IAA in combination with (3.0 mg/L). The shoots elongated and rooted directly in vermiculite after a pulse treatment with IBA (2.5 mg/L) for 15 min. Fungus growth, a serious problem in S. emarginatus tissue culture, was controlled using a fungicide, Bavistin, along with elimination of organic nutrients from the growth medium.
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Five Rhizobium strains (Cb1, Cb2, Cb3, Cb4 and Cb5) were isolated from root nodules of cluster bean [Cyamopsis tetragonoloba (L.)] on yeast extract mannitol agar (YMA) medium. All the five Rhizobium isolates have shown the Indole Acetic Acid( IAA) production in culture medium supplemented with L-tryptophan. The IAA content in culture supernatant was estimated by using the colorimetric method (13). All the five Rhizobium isolates produced maximum amount of IAA in medium supplemented with 2.5mg/ml Ltryptophan concentration. Production of IAA was maximum at 72h of incubation when bacteria reached the stationary phase. The cultural conditions were optimized for maximum IAA production by using different carbon and nitrogen sources as well as changing the incubation period. Glucose and L-asparagine were found to be the best carbon and nitrogen sources, respectively for maximum IAA production. The cell wall affecting agent, penicillin increased the IAA production up to 77.95% in Cb4, 59.52% in Cb5 and 37.84% in Cb3 isolates, over the control. Among the five isolates studied, isolate Cb4 showed better performance in IAA production.
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Objective To investigate dynamic changes in extracellular striatal 5-hydroxy indole acetic acid (5-HIAA) and melatonin (MLT) concentrations in the 6-hydroxydopamine (6-OHDA)-induced Parkinson's disease (PD) rat models.Methods A hemiparkinsonium rat model was established by a unilateral injection of 6-OHDA into the right substantia nigra pars compacta (SNc) and the right medial forebrain bundle (MFB).Dialysate samples were collected at 10:00 in the lesioned striatum by microdialysis at 1,2,3 and 4 weeks post-lesion,respectively.The levels of dopamine (DA) and 5-HIAA,as well as MLT in dialysate sanples were measured by high performance liquid chromotorgraphy (HPLC).Results One week after surgery,the level of DA in PD group was (1.19±0.22) ng/ml,which was distinctly lower than those in the vehicle group ((8.62 ± 0.73) ng/ml) and the sham group ((8.73 ± 0.78) ng/ml) (P ＜ 0.01).The levels of 5-HIAA in PD group had a downward trend,but there were no significant differences.The level of MLT in PD group was (43.31 ± 11.37) pg/ml at 4 weeks post-lesion,and significantly higher than those in the vehicle group ((19.13 ± 5.38)pg/ml) and the sham group ((19.80 ± 6.96) pg/ml) (P＜ 0.05).The striatal dialysate DA and 5-HIAA concentrations had a good positive correlation in the PD group (r =0.867,P ＜ 0.01).Conclusion Decreased DA level concomitantly with changes of 5-HIAA and MLT in the ipsilateral striatum of 6-OHDA-induced PD rats,and these changes may be related to PD progression.
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Five species of Azospirillum isolated from Manakkudi mangrove ecosystem were subjected for their efficiency to find out their growth parameters potential for the successful establishment of mangrove seedlings. Of the isolated five Azospirillum species, Azospirillum lipoferum (60%) was found to be the dominant one. But the level of maximum indole acetic acid (IAA) production (19.8mg.ml-1) and nitrogen fixation (5.9 C2H2hr-1) was identified with A. brasilense. Further, A. brasilense showed significant (p<0.05) level of increased growth parameters [maximum root length (29.55%), average root length (7.39%), total Chl (55.36%), carrotenoids (28.57%), Chl b (37.50%), carbohydrates (90.91%) and total amino acids (78.95%)] in Avicennia officinals when compared with control group. Further, A. brasilense also showed significant (p<0.05) level of increased growth parameters [average number of primary roots (40%), average biomass (44.44%), average shoot biomass (55.56%), total Chl (20%), Chl b (77.78%) and carotenoid (1.54%)] in C. decandra seedlings when compared with control group. Similarly, the average number of primary roots (23.08%), average root biomass (15.52%), average shoot biomass (15.30%), carbohydrate (20%) and total amino acids (44.44%) were found significant (p<0.05) in A. irakense inoculated R. apiculata seedlings. In conclusion, Azospirillum brasilense was found better for the growth of Avicennia officinalis and Ceriops decandra seedlings, but Azospirillum irakense was found better for Rhizophora apiculata seedlings.
ABSTRACT
A cana-de-açúcar é uma fonte importante de alimento e bioenergia. Assim, o estudo da interação com bactérias endofíticas que fixam o nitrogênio atmosférico (FBN) e produzem o ácido indol acético (AIA) vem sendo amplamente explorado. Porém, devido à sensibilidade bacteriana, tanto a produção de AIA, como a FBN, podem sofrer o impacto de fatores edafoclimáticos. O objetivo deste trabalho foi avaliar a influência de diferentes concentrações de NaCl sobre o crescimento bacteriano, a FBN e a produção de AIA in vitro de linhagens bacterianas do gênero Burkholderia, isoladas endofiticamente de plantas de cana-de-açúcar, cultivadas no estado de Pernambuco. Para tanto, duas linhagens bacterianas endofíticas das espécies Burkholderia gladioli e B. heleia foram inoculadas em meio TSA (com L-triptofano) acrescido de cinco concentrações de NaCl: 0,1; 1; 10; 25 e 50 g.L-1 e incubadas sob agitação. O crescimento bacteriano e a produção de AIA foram avaliados através de um espectrofotômetro por 48 horas. Para o teste de fixação de nitrogênio, as linhagens foram inoculadas em meio LGI-P semi-sólido acrescido de cinco concentrações de NaCl: 0,1; 1; 10; 25 e 50 g.L1 e incubadas a 28ºC por 10 dias. Foi possível observar que altas concentrações de NaCl influenciaram negativamente o crescimento bacteriano e a produção do AIA in vitro por B. glaidoli e B. heleia. E que, concentrações de NaCl acima de 25 g.L-1 inibiram a capacidade de fixar nitrogênio, de ambas as linhagens.
The sugarcane is an important source of food and bioenergy. So, the study of its interaction with endophytic bacteria that fix atmospheric nitrogen (BNF) and produce indole acetic acid (IAA) has been widely explored. However, due to bacterial sensitivity, both the production of IAA as the BNF may suffer the impact of soil and climatic factors. The goal of this study was to evaluate the influence of the NaCl different concentrations on the bacterial growth, on the BNF and on the IAA production in vitro by endophytic bacterial strains of the genus Burkholderia isolated from sugarcane plants grown in the Pernambuco State. In this study, two endophytic bacterial strains of Burkholderia gladioli and B. heleia species were inoculated in TSA (with L-tryptophan) added of five NaCl concentrations: 0.1, 1, 10, 25 and 50 g.L-1 and incubated under agitation. Bacterial growth and IAA production were assessed using a spectrophotometer for 48 hours. The nitrogen fixation test was carried out by the inoculation of the bacteria in semi-solid LGP-I added of five NaCl concentrations: 0.1, 1, 10, 25 and 50 g.L-1 and incubated at 28°C during 10 days. It was observed that high concentrations of NaCl influenced negatively the bacterial growth and indole acetic acid production in vitro by B. glaidoli and B. heleia. Nevertheless, NaCl concentrations above 25 g.L-1 inhibited the ability to fix nitrogen in both strains.
Subject(s)
Sodium Chloride , Saltpetre Soils , Burkholderia , Saccharum , Burkholderia gladioli , Nitrogen Fixation , BiofuelsABSTRACT
A inoculação de plantas leguminosas com rizóbios é um dos principais métodos biotecnológicos de utilização de micro-organismos em plantas visando à fixação biológica de nitrogênio na agricultura. No entanto, nos últimos anos, vêm sendo observada nesses micro-organismos a capacidade de produção de fitohormônios, principalmente o ácido indol-acético (AIA) e a promoção de crescimento em gramíneas. Dessa forma, os objetivos deste trabalho foram quantificar o ácido indol-acético produzido por rizóbios isolados de alfafa, avaliar o efeito da inoculação desses micro-organismos na germinação de sementes de arroz e realizar a caracterização genética desses isolados. Nove rizóbios isolados de nódulos de alfafa foram avaliados quanto a sua capacidade de produção de equivalentes de AIA e a influência da inoculação desses micro-organismos na germinação e desenvolvimento de plântulas de arroz. Os rizóbios produtores de AIA foram identificados pelo sequenciamento da região do gene 16S do DNAr. A produção de equivalentes ao ácido indol-acético foi observada em todos rizóbios, com valores que variaram de 43,04 a 101,26µg mL-1 em meio de cultura. Com relação à germinação das sementes de arroz, a inoculação com rizóbios acelerou o processo e o crescimento de suas plântulas. Os rizóbios UFRGS Ms58, Ms515, Ms195, Ms205, Ms2010 e 2012 foram identificados como pertencentes à espécie Sinorhizobium meliloti e UFRGS Ms55, Ms72 e Ms75 à espécie Rhizobium sp.
The inoculation of leguminous plants with rhizobia is one of the main methods of biotechnological use of microorganisms in order to obtain biological nitrogen fixation in agriculture. However, in recent years it has been attributed to these microorganisms the ability to produce phytohormones, mainly indole acetic acid (IAA), and to promote the growth in grasses. Thus, the objectives of this study were to quantify the indole acetic acid produced by rhizobia from alfalfa and to evaluate the effect of inoculation of these microorganisms on the germination of rice seed and to perform the genetic characterization of these isolates. Nine rhizobia, from nodules of alfalfa, were evaluated for their ability to produce IAA equivalents and for their influence in inoculating these microorganisms on germination and seedling development of rice. Moreover, these rhizobia producers of IAA were identified by the 16S region of DNAr. The equivalent production of indole acetic acid was observed in all tested isolates, with values ranging from 43.04 to 101.26µg mL-1 in culture medium. Regarding the germination of rice seeds, the inoculation with rhizobia accelerated this germination and its growth. Microorganisms UFRGS Ms58, UFRGS Ms515, UFRGS Ms195, UFRGS Ms205, UFRGS Ms2010 and UFRGS 2012 were identified as belonging to the species of Sinorhizobium meliloti. Microorganisms Ms55 UFRGS, UFRGS Ms75 and UFRG Ms72 were identified as belonging to the species of Rhizobium sp.