Harikesh Bahadur Singh

Bio: Harikesh Bahadur Singh is an academic researcher from Institute of Agricultural Sciences, Banaras Hindu University. The author has contributed to research in topics: Trichoderma & Trichoderma harzianum. The author has an hindex of 46, co-authored 307 publications receiving 7372 citations. Previous affiliations of Harikesh Bahadur Singh include Central Institute of Medicinal and Aromatic Plants & Pandit Ravishankar Shukla University.

Abiotic stress responses and microbe-mediated mitigation in plants: The omics strategies

Abstract: Abiotic stresses are the foremost limiting factors for agricultural productivity. Crop plants need to cope up adverse external pressure created by environmental and edaphic conditions with their intrinsic biological mechanisms, failing which their growth, development, and productivity suffer. Microorganisms, the most natural inhabitants of diverse environments exhibit enormous metabolic capabilities to mitigate abiotic stresses. Since microbial interactions with plants are an integral part of the living ecosystem, they are believed to be the natural partners that modulate local and systemic mechanisms in plants to offer defence under adverse external conditions. Plant-microbe interactions comprise complex mechanisms within the plant cellular system. Biochemical, molecular and physiological studies are paving the way in understanding the complex but integrated cellular processes. Under the continuous pressure of increasing climatic alterations, it now becomes more imperative to define and interpret plant-microbe relationships in terms of protection against abiotic stresses. At the same time, it also becomes essential to generate deeper insights into the stress-mitigating mechanisms in crop plants for their translation in higher productivity. Multi-omics approaches comprising genomics, transcriptomics, proteomics, metabolomics and phenomics integrate studies on the interaction of plants with microbes and their external environment and generate multi-layered information that can answer what is happening in real-time within the cells. Integration, analysis and decipherization of the big-data can lead to a massive outcome that has significant chance for implementation in the fields. This review summarizes abiotic stresses responses in plants in-terms of biochemical and molecular mechanisms followed by the microbe-mediated stress mitigation phenomenon. We describe the role of multi-omics approaches in generating multi-pronged information to provide a better understanding of plant-microbe interactions that modulate cellular mechanisms in plants under extreme external conditions and help to optimize abiotic stresses. Vigilant amalgamation of these high-throughput approaches supports a higher level of knowledge generation about root-level mechanisms involved in the alleviation of abiotic stresses in organisms.

Biofabricated Silver Nanoparticles Act as a Strong Fungicide against Bipolaris sorokiniana Causing Spot Blotch Disease in Wheat

Abstract: The present study is focused on the extracellular synthesis of silver nanoparticles (AgNPs) using culture supernatant of an agriculturally important bacterium, Serratia sp. BHU-S4 and demonstrates its effective application for the management of spot blotch disease in wheat. The biosynthesis of AgNPs by Serratia sp. BHU-S4 (denoted as bsAgNPs) was monitored by UV–visible spectrum that showed the surface plasmon resonance (SPR) peak at 410 nm, an important characteristic of AgNPs. Furthermore, the structural, morphological, elemental, functional and thermal characterization of bsAgNPs was carried out using the X-ray diffraction (XRD), electron and atomic microscopies, energy dispersive X-ray (EDAX) spectrometer, FTIR spectroscopy and thermogravimetric analyzer (TGA), respectively. The bsAgNPs were spherical in shape with size range of ∼10 to 20 nm. The XRD and EDAX analysis confirmed successful biosynthesis and crystalline nature of AgNPs. The bsAgNPs exhibited strong antifungal activity against Bipolaris sorokiniana, the spot blotch pathogen of wheat. Interestingly, 2, 4 and 10 µg/ml concentrations of bsAgNPs accounted for complete inhibition of conidial germination, whereas in the absence of bsAgNPs, conidial germination was 100%. A detached leaf bioassay revealed prominent conidial germination on wheat leaves infected with B. sorokiniana conidial suspension alone, while the germination of conidia was totally inhibited when the leaves were treated with bsAgNPs. The results were further authenticated under green house conditions, where application of bsAgNPs significantly reduced B. sorokiniana infection in wheat plants. Histochemical staining revealed a significant role of bsAgNPs treatment in inducing lignin deposition in vascular bundles. In summary, our findings represent the efficient application of bsAgNPs in plant disease management, indicating the exciting possibilities of nanofungicide employing agriculturally important bacteria.

Unraveling the efficient applications of secondary metabolites of various Trichoderma spp.

Abstract: Recent shift in trends of agricultural practices from application of synthetic fertilizers and pesticides to organic farming has brought into focus the use of microorganisms that carryout analogous function. Trichoderma spp. is one of the most popular genera of fungi commercially available as a plant growth promoting fungus (PGPF) and biological control agent. Exploitation of the diverse nature of secondary metabolites produced by different species of Trichoderma augments their extensive utility in agriculture and related industries. As a result, Trichoderma has achieved significant success as a powerful biocontrol agent at global level. The endorsement of Trichoderma spp. by scientific community is based on the understanding of its mechanisms of action against a large set of fungal, bacterial and in certain cases viral infections. However, it is still an agnostic view that there could be any single major mode of operation, although it is argued that all mechanisms operate simultaneously in a synchronized fashion. The central idea behind this review article is to emphasize the potentiality of applications of target specific secondary metabolites of Trichoderma for controlling phytopathogens as a substitute of commercially available whole organism formulations. With the aim to this point, we have compiled an inclusive list of secondary metabolites produced by different species of Trichoderma and their applications in diverse areas with the major emphasis on agriculture. Outlining the importance and diverse activities of secondary metabolites of Trichoderma besides its relevance to agriculture would generate greater understanding of their other important and beneficial applications apart from target specific biopesticides.

Silver Nanoparticles: Synthesis, Characterization, Properties, Applications, and Therapeutic Approaches

Abstract: Recent advances in nanoscience and nanotechnology radically changed the way we diagnose, treat, and prevent various diseases in all aspects of human life. Silver nanoparticles (AgNPs) are one of the most vital and fascinating nanomaterials among several metallic nanoparticles that are involved in biomedical applications. AgNPs play an important role in nanoscience and nanotechnology, particularly in nanomedicine. Although several noble metals have been used for various purposes, AgNPs have been focused on potential applications in cancer diagnosis and therapy. In this review, we discuss the synthesis of AgNPs using physical, chemical, and biological methods. We also discuss the properties of AgNPs and methods for their characterization. More importantly, we extensively discuss the multifunctional bio-applications of AgNPs; for example, as antibacterial, antifungal, antiviral, anti-inflammatory, anti-angiogenic, and anti-cancer agents, and the mechanism of the anti-cancer activity of AgNPs. In addition, we discuss therapeutic approaches and challenges for cancer therapy using AgNPs. Finally, we conclude by discussing the future perspective of AgNPs.

Effect of Temperature

Abstract: A positive temperature coefficient is the term which has been used to indicate that an increase in solubility occurs as the temperature is raised, whereas a negative coefficient indicates a decrease in solubility with rise in temperature.