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1

Salicylic acid-induced salinity tolerance in corn grown under NaCl stress

100%
Gautam S., Singh P. K.
Acta Physiologiae Plantarum
|
2009
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tom 31
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nr 6
Effects of salicylic acid on some physiological and biochemical characteristics of maize (Zea mays L.) seedlings under NaCl stress were studied. Pre-soaking treatments of NaCl (0, 50, 100 and 200 mM) were given to maize seeds in the presence as well as in the absence of 0.5 mM salicylic acid. Two-week-old maize seedlings exhibited significant decrease in dry weight, root length, shoot length and leaf area on 6 h exposure of 100 and 200 mM NaCl stress. Photosynthetic pigments and NR activity in leaves decreased sharply with increasing stress levels. Both proline content and lipid peroxidation (measured in terms of MDA) levels increased significantly under saline conditions. However, seedlings pretreated with 0.5 mM salicylic acid along with the salinity levels showed enhancement in growth parameters, photosynthetic pigments, NR activity while, free proline and MDA levels decreased. The results showed that salt-induced deleterious effects in maize seedlings were significantly encountered by the pretreatment of salicylic acid. It is concluded that 0.5 mM salicylic acid improves the adaptabilities of maize plants to NaCl stress.
2

Role of salicylic acid on physiological and biochemical mechanism of salinity stress tolerance in plants

100%
Singh P. K., Gautam S.
Acta Physiologiae Plantarum
|
2013
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tom 35
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nr 08
Salinity stress is one of the major abiotic stresses affecting plant growth and productivity globally. In order to improve the yields of plants growing under salt stress bear remarkable importance to supply sustainable agriculture. Acclimation of plants to salinized condition depends upon activation of cascade of molecular network involved in stress sensing/perception, signal transduction, and the expression of specific stress-related genes and metabolites. Isolation of salt overly sensitive (SOS) genes by sos mutants shed us light on the relationship between ion homeostasis and salinity tolerance. Regulation of antioxidative system to maintain a balance between the overproduction of reactive oxygen species and their scavenging to keep them at signaling level for reinstating metabolic activity has been elucidated. However, osmotic adaptation and metabolic homeostasis under abiotic stress environment is required. Recently, role of phytohormones like Abscisic acid, Jasmonic acid, and Salicylic acid in the regulation of metabolic network under osmotic stress condition has emerged through crosstalk between chemical signaling pathways. Thus, abiotic stress signaling and metabolic balance is an important area with respect to increase crop yield under suboptimal conditions. This review focuses on recent developments on improvement in salinity tolerance aiming to contribute sustainable plant yield under saline conditions in the face of climate change.
3

The spatial patterns of oxidative stress indicators co-locate with early signs of natural senescence in maize leaves

81%
Tewari R. K., Singh P. K., Watanabe M.
Acta Physiologiae Plantarum
|
2013
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tom 35
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nr 03
Reactive oxygen species play a crucial role for various physiological and developmental processes in plants. Here, we report a spatial pattern of oxidative stress and antioxidant defence within maize leaf. Localization of hydrogen peroxide in different region of leaf clearly exhibits well-defined increasing pattern of accumulation from the base to the leaf tip. Lipid peroxidation, an index of oxidative damage, also showed a similar pattern-like hydrogen peroxide that is lowest at the base and highest at the leaf tip. NADPH oxidase, an enzyme responsible for superoxide anion generation, showed highest activity in the leaf tip and least in the leaf base regions. Superoxide dismutase (SOD) activity was increased from the base to the leaf tip. Peroxidases, DAB-peroxidase (DAB-POD) and guaiacol-peroxidase (G-POD), catalase (CAT) and glutathione reductase (GR) also showed increases in their activities from the base to the leaf tip. Ascorbate peroxidase (APX), however, showed a reverse trend—highest at the base and least in the leaf tip. The decrease in APX and increases in the activities of other antioxidant enzymes SOD, CAT, DAB-POD, G-POD and GR along with H2O2 and lipid peroxidation, ascorbate/dehydroascorbate and non-protein thiol levels from the base to the leaf tip clearly exhibit a spatial pattern prior to the onset of visible signs of senescence in the maize leaf.
4
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Identifying overlapping phylogenetic and geographic roots of HIV - 1 evolution through computational analyses

61%
Singh P. K., Banik R., Chakraborty H. J., Das S. G., Ganguli S., Datta A.
International Letters of Natural Sciences
|
2014
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tom 02
HIV-1 or Human Immuno Deficiency Virus-1 is the main causative agent of Acquired Immuno Deficiency Syndrome (AIDS). Human host infected with HIV - 1 extensively harbours many viral variants but very little is known about the difference in pattern[17] of evolution of phylogenetic lineages of HIV-1 non recombinant, normal inter subtype recombinant and main two specific recombinant forms of HIV-1 i.e., Circulating Recombinant Forms (CRFs) and Unique Recombinant Forms (URFs). This study is mainly concerned with study of the difference in evolutionary lineages of non-recombinant and recombinant sequences of HIV-1 genome sequences and identification of geographically rich areas which has reported high degree of HIV-1 occurrence and variety. Total 1550 HIV-1 genome sequences were obtained from HIV Los Alamos Database. The sequences were aligned using MAFFT (Multiple Alignment using Fast Fourier Transform) web server tool. Alignment was carried out using 10 different set of alignment parameter values. After alignment the aligned file was used for constructing N-J phylogenetic tree using Clustal X2 tool. Phylogenetic analysis was performed keeping in mind the category to which the sequence belongs. Upon analysis it was observed that the clade containing the probable ancestor belongs remained constant in all cases of different alignment values. Non recombinant isolates, inter subtype recombinants, CRFs, URFs all followed different patterns of evolution. Non recombinant sequences were found geographically specific and subtype specific to some extent whereas, normal recombinants were subtype specific and less geographically specific. CRFs showed variation among the pattern of their evolution. At some instances the sequences occurred as sister taxa of non-recombinant or normal inter subtype recombinant sequences, while at some instances as sister taxa of other CRFs where they were geographically specific. Three CRFs existed as completely diverged sequences. URFs were four in number; two of them were Indian isolates of while other two were Japanese isolates. URFs were found to be totally geographically specific. Geography wise high rate of variation was observed in India and Japan as these two countries had sequences belonging to all of the above categories. Cameroon and South Africa have very large number isolates and a considerable amount of genetic variation among isolates but they lack URFs.
5

Salt stress tolerance of methylotrophic bacteria Methylophilus sp. and Methylobacterium sp. isolated from coal mine spoils

61%
Giri D. D., Kumar A., Shukla P. N., Singh R., Singh P. K., Pandey K. D.
Polish Journal of Microbiology
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2013
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tom 62
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nr 3
Two methylotrophic strains of Bina coalmine spoil BNV7b and BRV25 were identified based on physiological traits and 16S rDNA sequence as Methylophilus and Methylobacterium species. The strains exhibited similar carbon utilization but differed in N utilization and their response to the metabolic inhibitors. Methylophilus sp. was less tolerant to salt stress and it viability declined to one tenth within 4 h of incubation in 2M NaCl due to membrane damage and leakage of the intracellular electrolytes as evident from malondiaaldehyde (MDA) assay. In 200 mM NaCl, they exhibited increased superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) activity while in 500 mM NaCl, enzyme activities declined in Methylophilus sp. and increased in Methylobacterium sp. Among exogenously applied osmoprotectants proline was most efficient; however, polyols (mannitol, sorbitol and glycerol) also supported growth under lethal NaCl concentration.
6
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Isolation and computational characterization of glutathione peroxidase gene from an aquatic fern - Salvinia molesta

61%
Rahaman S., Singh P. K., Basu P., Gupta S., Basu M., Ganguli S.
International Letters of Natural Sciences
|
2016
|
tom 51
Pteridophytes and more specifically ferns represent a large but threatened group of plants which often serve as important environmental markers for pollution. Reports regarding stress responses in ferns are rare, apart from a few studies involving the ecological distribution and molecular marker studies. This work isolates a glutathione peroxidase enzyme from an aquatic fern widely distributed in fresh and polluted water bodies adjacent to sources of environmental polluted sources. Further computational analyses were performed to study the structure of the protein encoded by the open reading frame. Results indicate the presence of a large number of binding pockets which serve as important binding sites in the interactions with the cognate ligands.
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