Publications by authors named "Jyoti Kumar Thakur"

6 Publications

  • Page 1 of 1

Amelioration of short-term drought stress during different growth stages in Brassica juncea by rhizobacteria mediated maintenance of ROS homeostasis.

Physiol Plant 2021 Aug 18;172(4):1880-1893. Epub 2021 Apr 18.

Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi, India.

In the present investigation, the role of rhizobacteria in alleviating the deleterious effects of drought on mustard was assessed. The plants were exposed to short-term water shortages, during the vegetative and reproductive growth stages. Drought stress in both stages had a negative effect on growth, physiological, and biochemical parameters of mustard. Both the root and shoot biomass were significantly reduced in plants exposed to drought, but rhizobacterial inoculation resulted in better plant biomass than uninoculated plants. The ameliorative effects of inoculation were also indicated by improved relative water content, membrane stability index, total chlorophyll content, and photosynthetic parameters. Similarly, inoculation resulted in enhanced activity of antioxidative enzymes superoxide dismutase (SOD), ascorbate peroxidase, and catalase in both stages of growth which possibly increased stress tolerance by maintaining reactive oxygen species (ROS) homeostasis. There was a significant reduction in the accumulation of H O , proline and total soluble sugar in rhizobacteria treated plants under drought, suggesting that the treated plants did not encounter much stress and could maintain better plant health than uninoculated plants. Expression analysis of the BjP5CSB and BjFeSOD genes was conducted during both the growth stages. Expression of the BjP5CSB gene was significantly down-regulated in inoculated plants under drought, while BjFeSOD gene transcript levels were upregulated. The vegetative stage was more responsive to rhizobacterial inoculations than the reproductive stage under drought. Principal component analysis indicated a differential response by the two growth stages to inoculation. Hence, results indicate that these rhizobacteria reduce the negative impacts of drought in mustard by maintaining ROS homeostasis.
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http://dx.doi.org/10.1111/ppl.13399DOI Listing
August 2021

In situ decomposition of crop residues using lignocellulolytic microbial consortia: a viable alternative to residue burning.

Environ Sci Pollut Res Int 2021 Feb 24. Epub 2021 Feb 24.

ICAR-Indian Institute of Soil Science, Bhopal, 462038, India.

Open field burning of crop residue causes severe air pollution and greenhouse gas emission contributing to global warming. In order to seek an alternative, the current study was initiated to explore the prospective of lignocellulolytic microbes to expedite in situ decomposition of crop residues. Field trials on farmers' field were conducted in the state of Haryana and Maharashtra, to target the burning of rice and wheat residue and sugarcane trash, respectively. A comparative study among crop residue removal (CRR), crop residue burning (CRB) and in situ decomposition of crop residues (IND) revealed that IND of rice and wheat residues took 30 days whereas IND of sugarcane trash took 45 days. The decomposition status was assessed by determining the initial and final lignin to cellulose ratio which increased significantly from 0.23 to 0.25, 0.21 to 0.23 and 0.24 to 0.27 for rice, wheat residues and sugarcane trash, respectively. No yield loss was noticed in IND for both rice-wheat system and sugarcane-based system; rather IND showed relatively better crop yield as well as soil health parameters than CRB and CRR. Furthermore, the environmental impact assessment of residue burning indicated a substantial loss of nutrients (28-31, 23-25 and 51-77 kg ha of N+PO+KO for rice, wheat and sugarcane residue) as well as the emission of pollutants to the atmosphere. However, more field trials, as well as refinement of the technology, are warranted to validate and establish the positive potential of in situ decomposition of crop residue to make it a successful solution against the crop residue burning.
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http://dx.doi.org/10.1007/s11356-021-12611-8DOI Listing
February 2021

Antioxidant, physiological and biochemical responses of drought susceptible and drought tolerant mustard (Brassica juncea L) genotypes to rhizobacterial inoculation under water deficit stress.

Plant Physiol Biochem 2019 Oct 26;143:19-28. Epub 2019 Aug 26.

Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi, 110 012, India.

Response of drought susceptible (DS) genotype Pusa Karishma LES-39 and drought tolerant (DT) mustard genotype NPJ-124, to rhizobacterial inoculation under water deficit stress, was compared in the present study to determine the influence of inoculants on biochemical and physiological attributes of these two different genotypes. Inoculation was observed to improve root and shoot dry weight in both the genotypes, although better results were observed in the DS genotype. There was variation in the response of the two genotypes to rhizobacterial inoculation, under water deficit stress. Significant improvement in most of the physiological and biochemical parameters including antioxidative enzyme activities of the DS genotype; with concomitant decrease in starch content, accumulation of HO and lipid peroxidation upon inoculation of rhizobacteria was observed. In contrast, there was improvement in only few physiological and biochemical parameters in the DT genotype in response to inoculation with rhizobacteria. There was significant increase in catalase enzyme activity along with concomitant decrease in lipid peroxidation. Thus, drought susceptibility of the mustard genotypes, NPJ-124 and Pusa Karishma LES-39, determined their physiological, biochemical and antioxidative responses to rhizobacterial inoculation under water deficit stress. Expression of drought stress responsive genes belonging to ABA-dependent (RD20 and RD26) and ABA-independent (DREB2 and DREB1-2) pathways was studied in the DS genotype. Expression of DREB2 and DREB1-2 genes was considerably enhanced due to inoculation under water deficit stress; indicating that in Bacillus-mediated priming for drought stress tolerance, in this genotype, ABA-independent pathway probably played key role in enhancing tolerance to drought stress.
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http://dx.doi.org/10.1016/j.plaphy.2019.08.018DOI Listing
October 2019

Phylloplane bacteria of Jatropha curcas: diversity, metabolic characteristics, and growth-promoting attributes towards vigor of maize seedling.

Can J Microbiol 2017 Oct 31;63(10):822-833. Epub 2017 Jul 31.

Indian Institute of Soil Science, Nabibagh, Bhopal 462038, India.

The complex role of phylloplane microorganisms is less understood than that of rhizospheric microorganisms in lieu of their pivotal role in plant's sustainability. This experiment aims to study the diversity of the culturable phylloplane bacteria of Jatropha curcas and evaluate their growth-promoting activities towards maize seedling vigor. Heterotrophic bacteria were isolated from the phylloplane of J. curcas and their 16S rRNA genes were sequenced. Sequences of the 16S rRNA gene were very similar to those of species belonging to the classes Bacillales (50%), Gammaproteobacteria (21.8%), Betaproteobacteria (15.6%), and Alphaproteobacteria (12.5%). The phylloplane bacteria preferred to utilize alcohol rather than monosaccharides and polysaccharides as a carbon source. Isolates exhibited ACC (1-aminocyclopropane-1-carboxylic acid) deaminase, phosphatase, potassium solubilization, and indole acetic acid (IAA) production activities. The phosphate-solubilizing capacity (mg of PO solubilized by 10 cells) varied from 0.04 to 0.21. The IAA production potential (μg IAA produced by 10 cells in 48 h) of the isolates varied from 0.41 to 9.29. Inoculation of the isolates to maize seed significantly increased shoot and root lengths of maize seedlings. A linear regression model of the plant-growth-promoting activities significantly correlated (p < 0.01) with the growth parameters. Similarly, a correspondence analysis categorized ACC deaminase and IAA production as the major factors contributing 41% and 13.8% variation, respectively, to the growth of maize seedlings.
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http://dx.doi.org/10.1139/cjm-2017-0189DOI Listing
October 2017

Induction of osmoadaptive mechanisms and modulation of cellular physiology help Bacillus licheniformis strain SSA 61 adapt to salt stress.

Curr Microbiol 2015 Apr 6;70(4):610-7. Epub 2015 Jan 6.

Division of Microbiology, Indian Agricultural Research Institute, New Delhi, 10012, India,

Bacillus licheniformis strain SSA 61, originally isolated from Sambhar salt lake, was observed to grow even in the presence of 25 % salt stress. Osmoadaptive mechanisms of this halotolerant B. licheniformis strain SSA 61, for long-term survival and growth under salt stress, were determined. Proline was the preferentially accumulated compatible osmolyte. There was also increased accumulation of antioxidants ascorbic acid and glutathione. Among the different antioxidative enzymes assayed, superoxide dismutase played the most crucial role in defense against salt-induced stress in the organism. Adaptation to stress by the organism involved modulation of cellular physiology at various levels. There was enhanced expression of known proteins playing essential roles in stress adaptation, such as chaperones DnaK and GroEL, and general stress protein YfkM and polynucleotide phosphorylase/polyadenylase. Proteins involved in amino acid biosynthetic pathway, ribosome structure, and peptide elongation were also overexpressed. Salt stress-induced modulation of expression of enzymes involved in carbon metabolism was observed. There was up-regulation of a number of enzymes involved in generation of NADH and NADPH, indicating increased cellular demand for both energy and reducing power.
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http://dx.doi.org/10.1007/s00284-014-0761-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7001579PMC
April 2015

Degradation of sulphonated azo dye Red HE7B by Bacillus sp. and elucidation of degradative pathways.

Curr Microbiol 2014 Aug 30;69(2):183-91. Epub 2014 Mar 30.

Division of Soil Biology, Indian Institute of Soil Science, Bhopal, 462 038, Madhya Pradesh, India.

Bacteria capable of degrading the sulfonated azo dye Red HE7B were isolated from textile mill effluent contaminated soil. The most efficient isolate was identified as Bacillus sp. Azo1 and the isolate could successfully decolorize up to 89% of the dye. The decolorized cultural extract analyzed by HPLC confirmed degradation. Enzymatic analysis showed twofold and fourfold increase in the activity of azoreductase and laccase enzymes, respectively, indicating involvement of both reductive and oxidative enzymes in biodegradation of Red HE7B. Degraded products which were identified by GC/MS analysis included various metabolites like 8-nitroso 1-naphthol, 2-diazonium naphthalene. Mono azo dye intermediate was initially generated from the parent molecule. This mono azo dye was further degraded by the organism, into additional products, depending on the site of cleavage of R-N=N-R molecule. Based on the degradation products identified, three different pathways have been proposed. The mechanism of degradation in two of these pathways is different from that of the previously reported pathway for azo dye degradation. This is the first report of a microbial isolate following multiple pathways for azo dye degradation. Azo dye Red HE7B was observed to be phytotoxic, leading to decrease in root development, shoot length and seedling fresh weight. However, after biotreatment the resulting degradation products were non-phytotoxic.
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http://dx.doi.org/10.1007/s00284-014-0571-2DOI Listing
August 2014
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