Tapan Kumar Mohanta

Identification of new members of the MAPK gene family in plants shows diverse conserved domains and novel activation loop variants

BackgroundMitogen Activated Protein Kinase (MAPK) signaling is of critical importance in plants and other eukaryotic organisms. The MAPK cascade plays an indispensible role in the growth and development of plants, as well as in biotic and abiotic stress responses. The MAPKs are constitute the most downstream module of the three tier MAPK cascade and are phosphorylated by upstream MAP kinase kinases (MAPKK), which are in turn are phosphorylated by MAP kinase kinase kinase (MAPKKK). The MAPKs play pivotal roles in regulation of many cytoplasmic and nuclear substrates, thus regulating several biological processes.ResultsA total of 589 MAPKs genes were identified from the genome wide analysis of 40 species. The sequence analysis has revealed the presence of several N- and C-terminal conserved domains. The MAPKs were previously believed to be characterized by the presence of TEY/TDY activation loop motifs. The present study showed that, in addition to presence of activation loop TEY/TDY motifs, MAPKs are also contain MEY, TEM, TQM, TRM, TVY, TSY, TEC and TQY activation loop motifs. Phylogenetic analysis of all predicted MAPKs were clustered into six different groups (group A, B, C, D, E and F), and all predicted MAPKs were assigned with specific names based on their orthology based evolutionary relationships with Arabidopsis or Oryza MAPKs.ConclusionWe conducted global analysis of the MAPK gene family of plants from lower eukaryotes to higher eukaryotes and analyzed their genomic and evolutionary aspects. Our study showed the presence of several new activation loop motifs and diverse conserved domains in MAPKs. Advance study of newly identified activation loop motifs can provide further information regarding the downstream signaling cascade activated in response to a wide array of stress conditions, as well as plant growth and development.

Aflatoxins: A Global Concern for Food Safety, Human Health and Their Management

The aflatoxin producing fungi, Aspergillus spp., are widely spread in nature and have severely contaminated food supplies of humans and animals, resulting in health hazards and even death. Therefore, there is great demand for aflatoxins research to develop suitable methods for their quantification, precise detection and control to ensure the safety of consumers’ health. Here, the chemistry and biosynthesis process of the mycotoxins is discussed in brief along with their occurrence, and the health hazards to humans and livestock. This review focuses on resources, production, detection and control measures of aflatoxins to ensure food and feed safety. The review is informative for health-conscious consumers and research experts in the fields. Furthermore, providing knowledge on aflatoxins toxicity will help in ensure food safety and meet the future demands of the increasing population by decreasing the incidence of outbreaks due to aflatoxins.

Biosynthesis of Silver Nanoparticles from Protium serratum and Investigation of their Potential Impacts on Food Safety and Control

Silver nanoparticles play an integral part in the evolution of new antimicrobials against the broad ranges of pathogenic microorganisms. Recently, biological synthesis of metal nanoparticles using plant extracts has been successfully consummated. In the present study, the biosynthesis of silver nanoparticles (AgNPs) was conducted using the leaf extract of plant Protium serratum, having novel ethnomedicinal. The synthesized AgNPs were characterized using UV-Visible spectroscopy, dynamic light scattering spectroscopy (DLS), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy. The DLS study revealed the surface charge of the resulted nanoparticles that was highly negative, i.e., −25.0 ± 7.84 mV and the size was 74.56 ± 0.46 nm. The phytochemical and FTIR analysis confirmed the role of water-soluble phyto-compounds for the reduction of silver ions to silver nanoparticles. The potential antibacterial activity of AgNPs was studied against the food borne pathogens viz. Pseudomonas aeruginosa (IC50 = 74.26 ± 0.14 μg/ml), Escherichia coli (IC50 = 84.28 ± 0.36 μg/ml), Bacillus subtilis (IC50 = 94.43 ± 0.4236 μg/ml). The in vitro antioxidant potential of AgNPs was evaluated using 1, 1-diphenyl-2-picryl-hydrazil (IC50 = 6.78 ± 0.15 μg/ml) and hydroxyl radical assay (IC50 = 89.58 ± 1.15 μg/ml). In addition, the cytotoxicity of AgNPs was performed against fibroblast cell line L-929 to evaluate their biocompatibility. The overall results of the present investigation displayed the potential use of P. serratum leaf extract as a good bio-resource for the biosynthesis of AgNPs and their implementation in diverse applications, specifically as antibacterial agent in food packaging and preservation to combat against various food borne pathogenic bacteria along with its pharmaceutical and biomedical applications.

Genome-wide identification of Calcineurin B-Like (CBL) gene family of plants reveals novel conserved motifs and evolutionary aspects in calcium signaling events

BackgroundCalcium ions, the most versatile secondary messenger found in plants, are involved in the regulation of diverse arrays of plant growth and development, as well as biotic and abiotic stress responses. The calcineurin B-like proteins are one of the most important genes that act as calcium sensors.ResultsIn this study, we identified calcineurin B-like gene family members from 38 different plant species and assigned a unique nomenclature to each of them. Sequence analysis showed that, the CBL proteins contain three calcium binding EF-hand domain that contains several conserved Asp and Glu amino acid residues. The third EF-hand of the CBL protein was found to posses the D/E-x-D calcium binding sensor motif. Phylogenetic analysis showed that, the CBL genes fall into six different groups. Additionally, except group B CBLs, all the CBL proteins were found to contain N-terminal palmitoylation and myristoylation sites. An evolutionary study showed that, CBL genes are evolved from a common ancestor and subsequently diverged during the course of evolution of land plants. Tajima’s neutrality test showed that, CBL genes are highly polymorphic and evolved via decreasing population size due to balanced selection. Differential expression analysis with cold and heat stress treatment led to differential modulation of OsCBL genes.ConclusionsThe basic architecture of plant CBL genes is conserved throughout the plant kingdom. Evolutionary analysis showed that, these genes are evolved from a common ancestor of lower eukaryotic plant lineage and led to broadening of the calcium signaling events in higher eukaryotic organisms.

Antimicrobial, Antioxidant and Cytotoxic Activity of Silver Nanoparticles Synthesized by Leaf Extract of Erythrina suberosa (Roxb.)

In this experiment, biosynthesized silver nanoparticles (AgNPs) were synthesized using aqueous leaf extract of Erythrina suberosa (Roxb.). The biosynthesis of silver nanoparticle was continuously followed by UV-vis spectrophotometric analysis. The response of the phytoconstituents resides in E. suberusa during synthesis of stable AgNPs were analyzed by ATR- fourier-transform infrared spectroscopy. Further, the size, charge, and polydispersity nature of AgNPs were studied using dynamic light scattering spectroscopy. The morphology of the nanoparticles was determined by scanning electron microscopy. Current result shows core involvement of plant extracts containing glycosides, flavonoids, and phenolic compounds played a crucial role in the biosynthesis of AgNPs. The antimicrobial activities of silver nanoparticles were evaluated against different pathogenic bacterium and fungi. The antioxidant property was studied by radical scavenging (DPPH) assay and cytotoxic activity was evaluated against A-431 osteosarcoma cell line by MTT assay. The characteristics of the synthesized silver nanoparticles suggest their application as a potential antimicrobial and anticancer agent.

Large Scale Screening of Ethnomedicinal Plants for Identification of Potential Antibacterial Compounds

The global burden of bacterial infections is very high and has been exacerbated by increasing resistance to multiple antibiotics. Antibiotic resistance leads to failed treatment of infections, which can ultimately lead to death. To overcome antibiotic resistance, it is necessary to identify new antibacterial agents. In this study, a total of 662 plant extracts (diverse parts) from 222 plant species (82 families, 177 genera) were screened for antibacterial activity using the agar cup plate method. The aqueous and methanolic extracts were prepared from diverse plant parts and screened against eight bacterial (two Gram-positive and six Gram-negative) species, most of which are involved in common infections with multiple antibiotic resistance. The methanolic extracts of several plants were shown to have zones of inhibition ≥ 12 mm against both Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration was calculated only with methanolic extracts of selected plants, those showed zone of inhibition ≥ 12 mm against both Gram-positive and Gram-negative bacteria. Several extracts had minimum inhibitory concentration ≤ 1 mg/mL. Specifically Adhatoda vasica, Ageratum conyzoides, Alangium salvifolium, Alpinia galanga, Andrographis paniculata, Anogeissus latifolia, Annona squamosa, A. reticulate, Azadirachta indica, Buchanania lanzan, Cassia fistula, Celastrus paniculatus, Centella asiatica, Clausena excavate, Cleome viscosa, Cleistanthus collinus, Clerodendrum indicum, Croton roxburghii, Diospyros melanoxylon, Eleutherine bulbosa, Erycibe paniculata, Eryngium foetidum, Garcinia cowa, Helicteres isora, Hemidesmus indicus, Holarrhena antidysenterica, Lannea coromandelica, Millettia extensa, Mimusops elengi, Nyctanthes arbor-tristis, Oroxylum indicum, Paederia foetida, Pterospermum acerifolium, Punica granatum, Semecarpus anacardium, Spondias pinnata, Terminalia alata and Vitex negundo were shown to have significant antimicrobial activity. The species listed here were shown to have anti-infective activity against both Gram-positive and Gram-negative bacteria. These results may serve as a guide for selecting plant species that could yield the highest probability of finding promising compounds responsible for the antibacterial activities against a broad spectrum of bacterial species. Further investigation of the phytochemicals from these plants will help to identify the lead compounds for drug discovery.

Genomics and evolutionary aspect of calcium signaling event in calmodulin and calmodulin-like proteins in plants

BackgroundCa2+ ion is a versatile second messenger that operate in a wide ranges of cellular processes that impact nearly every aspect of life. Ca2+ regulates gene expression and biotic and abiotic stress responses in organisms ranging from unicellular algae to multi-cellular higher plants through the cascades of calcium signaling processes.ResultsIn this study, we deciphered the genomics and evolutionary aspects of calcium signaling event of calmodulin (CaM) and calmodulin like- (CML) proteins. We studied the CaM and CML gene family of 41 different species across the plant lineages. Genomic analysis showed that plant encodes more calmodulin like-protein than calmodulins. Further analyses showed, the majority of CMLs were intronless, while CaMs were intron rich. Multiple sequence alignment showed, the EF-hand domain of CaM contains four conserved D-x-D motifs, one in each EF-hand while CMLs contain only one D-x-D-x-D motif in the fourth EF-hand. Phylogenetic analysis revealed that, the CMLs were evolved earlier than CaM and later diversified. Gene expression analysis demonstrated that different CaM and CMLs genes were express differentially in different tissues in a spatio-temporal manner.ConclusionIn this study we provided in detailed genome-wide identifications and characterization of CaM and CML protein family, phylogenetic relationships, and domain structure. Expression study of CaM and CML genes were conducted in Glycine max and Phaseolus vulgaris. Our study provides a strong foundation for future functional research in CaM and CML gene family in plant kingdom.

Green synthesis and antimicrobial activity of silver nanoparticles using wild medicinal mushroom Ganoderma applanatum (Pers.) Pat. from Similipal Biosphere Reserve, Odisha, India.

In the present study, green synthesis and cost effective approach of silver nanoparticles using wild medicinal mushroom Ganoderma applanatum (Pers.) Pat. from Similipal Biosphere Reserve, Odisha, India is reported. The biosynthesised AgNPs were characterised using UV-visible spectroscopy, particle analyser and scanning electron microscopy studies. It was found by dynamic light scattering analysis, that the average size and charges of the AgNPs were 133.0 ± 0.361 nm and -6.01 ± 5.30 mV, respectively. Moreover, the Fourier transform infrared study was also conducted to identify the biomolecules or functional groups responsible for the reduction of Ag and stabilisation of the AgNPs. The potential biomedical application with reference to antimicrobial activity of the synthesised AgNPs was investigated against some pathogenic microorganisms viz. Escherichia coli, Bacillus subtilis, Staphylococcus epidermidis, Vibrio cholerae, Staphylococcus aureus and Shigella flexneri.

Functional genomics and signaling events in mycorrhizal symbiosis

The symbiotic association between plant and arbuscular mycorrhizal fungi is an evolutionary conserved association that resulted from co-evolutionary events where both partners benefit from each other. Different plant genes, hormones, and miRNAs regulate this symbiotic association at different levels. Of those, the most important signaling molecules that play critical roles in symbiotic association are plant-derived strigolactones and fungal-derived lipochito-oligosaccharides. These molecules regulate the symbiotic association at the initial stage of symbiosis. Subsequent signaling events of these two molecules activate downstream signaling cascades to develop a proper symbiotic relationship between plants and fungi.

Systems biology approach in plant abiotic stresses

Plant abiotic stresses are the major constraint on plant growth and development, causing enormous crop losses across the world. Plants have unique features to defend themselves against these challenging adverse stress conditions. They modulate their phenotypes upon changes in physiological, biochemical, molecular and genetic information, thus making them tolerant against abiotic stresses. It is of paramount importance to determine the stress-tolerant traits of a diverse range of genotypes of plant species and integrate those traits for crop improvement. Stress-tolerant traits can be identified by conducting genome-wide analysis of stress-tolerant genotypes through the highly advanced structural and functional genomics approach. Specifically, whole-genome sequencing, development of molecular markers, genome-wide association studies and comparative analysis of interaction networks between tolerant and susceptible crop varieties grown under stress conditions can greatly facilitate discovery of novel agronomic traits that protect plants against abiotic stresses.