Browsing by Author "Rajesh Prasad Rastogi"

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Salt-tolerant plant growth-promoting Bacillus pumilus strain JPVS11 to enhance plant growth attributes of rice and improve soil health under salinity stress
(Elsevier GmbH, 2021) Akhilesh Kumar; Saurabh Singh; Arpan Mukherjee; Rajesh Prasad Rastogi; Jay Prakash Verma
Rice (Oryza sativa L.) growth and productivity has been negatively affected due to high soil salinity. However, some salt-tolerant plant growth-promoting bacteria (ST-PGPB) enhance crop growth and reduce the negative impacts of salt stress through regulation of some biochemical, physiological, and molecular features. Total thirty six ST-PGPB were isolated from sodic soil of eastern Uttar Pradesh, India, and screened for salt tolerance at different salt (NaCl) concentrations up to 2000 millimolar (mM). Out of thirty-six, thirteen strains indicated better growth and plant growth properties (PGPs) in NaCl amended medium. Among thirteen, one most effective Bacillus pumilus strain JPVS11 was molecularly characterized, which showed potential PGPs, such as indole-3-acetic acid (IAA),1-aminocyclo propane-1-carboxylicacid (ACC) deaminase activity, P-solubilization, proline accumulation and exopolysaccharides (EPS) production at different concentrations of NaCl (0 –1200 mM). Pot experiment was conducted on rice (Variety CSR46) at different NaCl concentrations (0, 50, 100, 200, and 300 mM) with and without inoculation of Bacillus pumilus strain JPVS11. At elevated concentrations of NaCl, the adverse effects on chlorophyll content, carotenoids, antioxidant activity was recorded in non-inoculated (only NaCl) plants. However, inoculation of Bacillus pumilus strain JPVS11 showed positive adaption and improve growth performance of rice as compared to non-inoculated in similar conditions. A significant (P < 0.05) enhancement plant height (12.90–26.48%), root length (9.55–23.09%), chlorophyll content (10.13–27.24%), carotenoids (8.38–25.44%), plant fresh weight (12.33–25.59%), and dry weight (8.66–30.89%) were recorded from 50 to 300 mM NaCl concentration in inoculated plants as compared to non-inoculated. Moreover, the plants inoculated with Bacillus pumilus strain JPVS11showed improvement in antioxidant enzyme activities of catalase (15.14–32.91%) and superoxide dismutase (8.68–26.61%). Besides, the significant improvement in soil enzyme activities, such as alkaline phosphatase (18.37–53.51%), acid phosphatase (28.42–45.99%), urease (14.77–47.84%), and β-glucosidase (25.21–56.12%) were recorded in inoculated pots as compared to non-inoculated. These results suggest that Bacillus pumilus strain JPVS11 is a potential ST-PGPB for promoting plant growth attributes, soil enzyme activities, microbial counts, and mitigating the deleterious effects of salinity in rice. © 2020 Elsevier GmbH
Ultraviolet radiation and cyanobacteria
(Elsevier, 2014) Rajesh Prasad Rastogi; Rajeshwar P. Sinha; Sang Hyun Moh; Taek Kyun Lee; Sreejith Kottuparambil; Youn-Jung Kim; Jae-Sung Rhee; Eun-Mi Choi; Murray T. Brown; Donat-Peter Häder; Taejun Han
Cyanobacteria are the dominant photosynthetic prokaryotes from an ecological, economical, or evolutionary perspective, and depend on solar energy to conduct their normal life processes. However, the marked increase in solar ultraviolet radiation (UVR) caused by the continuous depletion of the stratospheric ozone shield has fueled serious concerns about the ecological consequences for all living organisms, including cyanobacteria. UV-B radiation can damage cellular DNA and several physiological and biochemical processes in cyanobacterial cells, either directly, through its interaction with certain biomolecules that absorb in the UV range, or indirectly, with the oxidative stress exerted by reactive oxygen species. However, cyanobacteria have a long history of survival on Earth, and they predate the existence of the present ozone shield. To withstand the detrimental effects of solar UVR, these prokaryotes have evolved several lines of defense and various tolerance mechanisms, including avoidance, antioxidant production, DNA repair, protein resynthesis, programmed cell death, and the synthesis of UV-absorbing/screening compounds, such as mycosporine-like amino acids (MAAs) and scytonemin. This study critically reviews the current information on the effects of UVR on several physiological and biochemical processes of cyanobacteria and the various tolerance mechanisms they have developed. Genomic insights into the biosynthesis of MAAs and scytonemin and recent advances in our understanding of the roles of exopolysaccharides and heat shock proteins in photoprotection are also discussed. ©2014 Elsevier B.V. All rights reserved.