Department of Biological Sciences

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Author: search.filters.author.Jha, Prabhat N.Subject: search.filters.subject.ACC deaminase

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Now showing 1 - 6 of 6
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    Molecular identification and characterization of rhizospheric bacteria for plant growth promoting ability
    (IJCB, 2015) Jha, Prabhat N.
    The objective of this study was to isolate and characterize a rhizospheric bacterium from Sorgastrum nutans, growing around the desert region of Rajasthan (India). Plant growth promoting rhizobacteria (PGPR) are known to influence plant growth by various direct or indirect mechanisms. Isolated strain was tested for various PGP traits like 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, phosphate solubilization, indole acetic acid production, production of siderophore, nitrogen fixation and ammonia production. Bio-control ability of isolate was screened by antagonistic activity against certain fungal/bacterial pathogens as well as Hydrogen cyanide HCN production. Isolated test organism was also biochemically characterized. Further identification of isolate was performed by PCR based 16S rRNA gene sequencing. Moreover evaluation of the isolate SNP-18 exhibiting multiple plant growth promoting (PGP) traits on soil/plant system is on-going to uncover their efficacy as effective PGPR.
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    Plant Growth Promoting Potential of ACC Deaminase Rhizospheric Bacteria Isolated from Aerva javanica: A Plant Adapted to Saline Environments
    (IJCMAS, 2015) Jha, Prabhat N.
    The present study demonstrates the plant growth promoting features of a bacterial isolate isolated from rhizospheric roots of Aerva javanica, commonly growing around the Sambhar salt lake Rajasthan. Isolate was able to produce the indole-3- acetic acid and solubilize the inorganic phosphate. Based on 16SrRNA gene sequencing bacterial isolate belongs to Enterobacter cloaceae. Among the other PGP traits isolates were found to positive for ACC deaminase activity, nitrogen fixation and ammonia production. The strain has shown the tolerance to NaCl concentrations up to 6% (w/v), growing ability up to pH 11 and temperature of 50 °C. Isolate was showed production of industrially important enzymes that make it suitable for various biotechnological and agricultural applications. Moreover strain AJS-15 showed antibacterial and antifungal activities against certain pathogenic microorganism, illustrating its biocontrol ability. Therefore use of bacterium with multifarious traits could be used as biofertilizers for ameliorating the salt stress for the plants.
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    The plant-growth-promoting bacterium Klebsiella sp. SBP-8 confers induced systemic tolerance in wheat (Triticum aestivum) under salt stress
    (Elsiever, 2015) Jha, Prabhat N.
    Plant-growth-promoting bacteria (PGPB) with 1-aminocyclopropane-1-carboxylatedeaminase (ACCD) activity can protect plants from the deleterious effects of abioticstressors. An ACCD bacterial strain, SBP-8, identified as Klebsiella sp., also having other plant-growth-promoting activities, was isolated from Sorghum bicolor growing in the desertregion of Rajasthan, India. ACCD activity of SBP-8 was characterized at biochemical, physiological, and molecular levels. The presence of AcdS, a structural gene for ACCD, was confirmed by the polymerase chain reaction. Strain SBP-8 showed optimum growth and ACCD activity at increased salt (NaCl) concentrations of up to 6%, indicating its potential to survive and associate with plants growing in saline soil. Inoculation of wheat plants with SBP-8 when grow in the presence of salt (150–200 mM) and temperature (30–40 °C) stressors resulted inamelioration of stress conditions by increasing plant biomass and chlorophyll content, and are duction in plant growth inhibition (10–100%) occurred due to salt and temperature stressors. Moreover, strain SBP-8 also caused Na+ exclusion (65%) and increased uptake of K+ (84.21%) in the host plant. This property can protect plants from adverse effects of Na+ on plant growth and physiology. Thus, SBP-8 improves growth of the host plant and protects from salt stressors through more than one mechanism including an effect of ACCD activity and on K+/Na+ ratio in plants. The colonization efficiency of strain SBP-8 was confirmedby CFU (colony-forming unit) count, microscopy, and ERIC–PCR based DNA-finger-printing approach. Therefore, and the use of efficient colonizing plant-growth-promoting bacteria may provideinsights into possible biotechnological approaches to decrease the impact of salinity and other stressors.
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    Alleviation of salinity-induced damage on wheat plant by an ACC deaminase-producing halophilic bacterium Serratia sp. SL- 12 isolated from a salt lake
    (Springer, 2016-02) Jha, Prabhat N.
    Plant growth promoting bacteria (PGPB) with 1-aminocyclopropane-1-carboxylate deaminase (ACC deaminase) activity can be used to ameliorate salt stress in plants. The aim of this study was to characterize a salt-tolerant PGP bacterium Serratia sp. SL-12 isolated from a salt lake, and to evaluate its capability to promote growth in wheat plants (Triticum aestivum L) under conditions of salt stress. The isolate SL-12 exhibited other plant growth promoting properties such as the production of indole-3-acetic acid, and enabling solubilization of inorganic phosphate. An analysis of fatty acid composition of the isolate grown at different salt concentrations (150–200 mM) indicated that salt concentration strongly influenced the fatty acid composition, and increased the proportion of unsaturated fatty acids. Inoculation of SL-12 into wheat plants growing under salt stress (150–200 mM NaCl) resulted in a significant increase in plant growth, as measured by parameters such as shoot/root length, fresh/dry weight, and photosynthetic pigment accumulation. In addition, application of isolate SL-12 decreased the levels of Na+ by (65 %) and increased the uptake of K+ by (39 %), indicating a role in maintaining ionic homeostasis, and minimizing toxic ionic effects in host wheat plants. The growth of wheat seedling under salinity stress was improved by SL-12 by inducing accumulation of osmolytes such as total soluble sugar and total protein content, while reducing the salt-induced malondialdehyde content. This has been found by other researchers. The present study indicates the potential of isolate SL-12 as a biofertilizer for enhancing the growth of wheat and other crops under salt stress conditions.
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    Priming with ACC-utilizing bacterium attenuated copper toxicity, improved oxidative stress tolerance, and increased phytoextraction capacity in wheat
    (Springer, 2018) Jha, Prabhat N.
    The major challenges for the plants growing in metal-contaminated soils are deficiency of nutrients, biomass reduction, and severe oxidative damages in the presence of heavy metals. In this regard, our aim was to overcome these challenges through the use of efficient microbial strains in metal-polluted soils and to assess its/their physiological and biochemical effects. In the current study, a copper (Cu)-resistant bacterium was isolated from the rhizospheric soil of ‘Ziziphus nummularia’ and evaluated for its ability to promote the wheat growth under the gradient stress of copper. Based on 16S rRNA gene sequencing, the isolate was identified as Pantoea sp. Among the plant growth promoting tests, the isolate showed the production of indole acetic acid, solubilization of inorganic phosphate, and ACC deaminase activity. Also, the isolate showed resistance to many heavy metals and antibiotics and increased the water-soluble copper in solution. The results of pot studies showed that bacterial application promoted various growth parameters of wheat plants and also enhanced the Cu uptake of wheat from the Cu-amended soil. The results showed that enhancement of Cu stress (100 to 300 mg kg−1) resulted in a decrease in various compatible solutes such as proline, total soluble sugars, and total protein content, and increase in the level of malondialdehyde (MDA), latter of which is the indicator of oxidative stress. Bacterial treatment markedly increased the proline, soluble sugar, total protein content, and decreased the MDA content under Cu stress. In addition, bacterial inoculation significantly alleviated the harmful effect of metal toxicity by decreasing the activation of ROS molecules including superoxide (O2 −) and hydrogen peroxide (H2O2). The activation of various antioxidative enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) was noted following bacterial inoculation under Cu stress. Therefore, the present study demonstrates the potential of the isolate Pantoea sp. ZNP-5 to improve the growth and phytoextraction of metal from the metal-polluted soil through the polyphasic mechanism of action.
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    Effect of inoculation of zinc-resistant bacterium Enterobacter ludwigii CDP-14 on growth, biochemical parameters and zinc uptake in wheat (Triticum aestivum L.) plant
    (Elsiever, 2018-03) Jha, Prabhat N.; Mishra, Somesh; Raghuvanshi, Smita
    A metal resistant bacterium was isolated from the rhizosphere of Kair ‘Capparis decidua’ and screened for its phytoextraction ability under gradient metal stress conditions. Based on 16S rDNA analysis, the strain was identified as Enterobacter ludwigii. Among the plant growth promoting traits, isolate showed the ACC (1-aminocyclopropane-1-carboxylate) deaminase activity, production of indole-3-acetic acid in tryptophan supplemented medium and solubilize the inorganic phosphate. The isolate was resistant to heavy metals like zinc (Zn), nickel (Ni), copper (Cu), and cadmium (Cd). The fatty acid adaptation of isolate growing at different concentration of Zn (100–300 mg kg−1) was also studied, which indicated that metal concentration strongly influenced the fatty acid composition of bacterium, particularly by increasing the unsaturated fatty acids. Furthermore, inoculation with the test isolate was found to significantly (p < 0.01) increase the various growth parameters of wheat plants and also improve the photosynthetic pigments. In addition, inoculation with isolate resulted in significant (p < 0.01) increase in the Zn content in wheat plant under metal stress. Moreover, bacterial application significantly (p < 0.01) increased the various compatible solutes such as proline content (30–65%), total soluble sugar (9–49%), and decreased the malondialdehyde (MDA) content (38–47%) as compared to control, illustrating its protective effect under metal induced oxidative stress. Inoculation with test isolate also increased the total protein content in range of 16–52%. Our work revealed that metal resistant plant growth promoting rhizobacterium could be exploited as microbial mediated phytoremediation of metal polluted soils.