Mihir Halder

Bio: Mihir Halder is an academic researcher from Barasat Government College. The author has contributed to research in topics: Hairy root culture & Secondary metabolite. The author has an hindex of 7, co-authored 12 publications receiving 147 citations. Previous affiliations of Mihir Halder include University of Calcutta.

Elicitation: A biotechnological tool for enhanced production of secondary metabolites in hairy root cultures

Abstract: Elicitation is a possible aid to overcome various difficulties associated with the large-scale production of most commercially important bioactive secondary metabolites from wild and cultivated plants, undifferentiated or differentiated cultures. Secondary metabolite accumulation in vitro or their efflux in culture medium has been elicited in the undifferentiated or differentiated tissue cultures of several plant species by the application of a low concentration of biotic and abiotic elicitors in the last three decades. Hairy root cultures are preferred for the application of elicitation due to their genetic and biosynthetic stability, high growth rate in growth regulator-free media, and production consistence in response to elicitor treatment. Elicitors act as signal, recognized by elicitor-specific receptors on the plant cell membrane and stimulate defense responses during elicitation resulting in increased synthesis and accumulation of secondary metabolites. Optimization of various parameters, such as elicitor type, concentration, duration of exposure, and treatment schedule is essential for the effectiveness of the elicitation strategies. Combined application of different elicitors, integration of precursor feeding, or replenishment of medium or in situ product recovery from the roots/liquid medium with the elicitor treatment have showed improved accumulation of secondary metabolites due to their synergistic effect. This is a comprehensive review about the progress in the elicitation approach to hairy root cultures from 2010 to 2019 and the information provided is valuable and will be of interest for scientists working in this area of plant biotechnology.

Biotechnological Approaches for Production of Anti-Cancerous Compounds Resveratrol, Podophyllotoxin and Zerumbone.

Abstract: Secondary metabolites from numerous plant sources have been developed as anti- cancer reagents and compounds such as resveratrol, podophyllotoxin and zerumbone are of particular importance in this regard. Since their de novo chemical synthesis is both arduous and commercially expensive, there has been an impetus to develop viable, biotechnological methods of production. Accordingly, this review focuses on the recent developments in the field, highlighting the use of micropropagation, cell suspension cultures, callus cultures, hairy root cultures, recombinant microbes and genetically modified higher plants. Optimization of media and culture conditions, precursor feeding, immobilization and the use of chemical or physical elicitation in various protocols has led to an increase in resveratrol and podophyllotoxin production. Heterologous gene transformation of higher plants with stilbene synthase derived from Arachis hypogaea or Vitis vinifera lead to resveratrol production with the concomitant increase in resistance to plant pathogens. Interestingly, genetic transformation of Podophyllum hexandrum and Linum flavum with Agrobacterium rhizogenes resulted in Ri-T-DNA gene(s)-mediated enhancement of podophyllotoxin production. Zerumbone yields from tissue cultured plantlets or from suspension cultures are generally low and these methods require further optimization. In microbes lacking the native resveratrol or zerumbone biosynthesis pathway, metabolic engineering required not only the introduction of several genes of the pathway, but also precursor feeding and optimization of gene expression to increase their production. Data pertaining to safety and toxicity testing are needed prior to use of these sources of anti-cancer compounds in therapy.

A Critical Review on Biotechnological Interventions for Production and Yield Enhancement of Secondary Metabolites in Hairy Root Cultures

Abstract: In the past three decades, differentiated hairy root culture-related researches gained a great attention due to the equal or greater bio-production capacity of low amount, high-value secondary metabolites as compared to their parent plants with several advantages over undifferentiated cell suspension cultures in plants. This was mainly because hairy roots are capable of auxin-independent rapid growth and are genetically and biochemically stable, with high productivity and suitability for adaptation to large-scale systems. Nowadays, hairy root cultures of various plant species offer a novel promising opportunity and great prospects for in vitro mass production of economically important bioactive metabolites. At present, the productivity of desired compounds by hairy root cultures is generally too low to fulfill the demands of pharmaceutical industry owing to various biological and technological limitations. Screening and selection for high-yielding root lines and optimization of the culture media and the culture conditions like type of nutrient medium, salt strength, source of carbon and concentration, source of nitrogen and the ratio of NH4+/NO3−, concentration of phosphate, inoculum density, hydrogen ion concentration, temperature, and light intensity and quality have been taken as yield enhancement strategies among others, to produce desired secondary metabolites using hairy root cultures. Feasibility of commercial application of hairy root culture in bioreactors requires several optimization steps. This review highlights some of the recent progress and outlines future prospects for metabolite production and yield enhancement approaches in hairy root cultures for producing bioactive substances.

Karyotype analysis of three important traditional Indian medicinal plants, Bacopa monnieri, Tylophora indica and Withania somnifera

Abstract: Chromosome characters of three indigenous medicinal plants of high repute were studied. Their karyotypes were commonly mono-modal, decreasing in length from the longest to the shortest chromosomes. The chromosome complement in centromeric positions was 6sm+34M+24m for Bacopa monnieri (L.) Wettst. (2n = 64), 2m.st+12M+6sm+2m for Tylophora indica (Burm.f.) Merrill (2n = 22) and 2m.st+4m.sm+4M+18m+20sm for Withania somnifera (L.) Dunal (2n = 48).

Enhanced trans-resveratrol production in genetically transformed root cultures of Peanut (Arachis hypogaea L.)

Abstract: In the present study, 30 Ri-transformed root lines of peanut (Arachis hypogaea) cv. JL-24, a popular Indian cultivar, obtained following infection with Agrobacterium rhizogenes strains LBA9402, A4 and R1000 were selected on the basis of growth index and maintained in vitro for 3 years. The root lines showed high degree of branching and rapid, plagiotropic growth on phytohormone free solid N/5 medium but were devoid of root hairs. Trans-resveratrol was isolated by preparative HPLC from Ri-transformed roots and identified by ESI–MS/MS. Strain independent variability was observed among 30 Ri-transformed root lines on the basis of lateral root density per cm (7.60 ± 0.30 to 4.5 ± 0.5), relative thickness (0.54 ± 0.07 to 1.54 ± 0.1 mm), growth index (9.16 ± 1.1 to 17.79 ± 1.35 FW basis and 10.77 ± 0.95 to 19.46 ± 1.78 DW basis) and trans-resveratrol content 0.27 ± 0.03 (root line R1000-1) to 0.969 ± 0.141 mg g DW−1 (root line RIX-19) in solid N/5 medium, which was 4.1–14 fold greater than in excised non-transformed root cultures (0.06 ± 0.01 mg g DW−1). Optimum growth and productivity in liquid culture was achieved in N/5 medium supplemented with 0.01 % activated charcoal. Root line RIX-19 showed maximum trans-resveratrol accumulation (1.21 ± 0.09 mg g DW−1) and productivity (0.37 ± 0.08 mg per flask), which was 19 fold higher than non-transformed root cultures. This optimized protocol can be utilized for large scale cultivation of transformed root cultures in industrial bioreactors for mass synthesis of trans-resveratrol.

Elicitation: A biotechnological tool for enhanced production of secondary metabolites in hairy root cultures

Abstract: Elicitation is a possible aid to overcome various difficulties associated with the large-scale production of most commercially important bioactive secondary metabolites from wild and cultivated plants, undifferentiated or differentiated cultures. Secondary metabolite accumulation in vitro or their efflux in culture medium has been elicited in the undifferentiated or differentiated tissue cultures of several plant species by the application of a low concentration of biotic and abiotic elicitors in the last three decades. Hairy root cultures are preferred for the application of elicitation due to their genetic and biosynthetic stability, high growth rate in growth regulator-free media, and production consistence in response to elicitor treatment. Elicitors act as signal, recognized by elicitor-specific receptors on the plant cell membrane and stimulate defense responses during elicitation resulting in increased synthesis and accumulation of secondary metabolites. Optimization of various parameters, such as elicitor type, concentration, duration of exposure, and treatment schedule is essential for the effectiveness of the elicitation strategies. Combined application of different elicitors, integration of precursor feeding, or replenishment of medium or in situ product recovery from the roots/liquid medium with the elicitor treatment have showed improved accumulation of secondary metabolites due to their synergistic effect. This is a comprehensive review about the progress in the elicitation approach to hairy root cultures from 2010 to 2019 and the information provided is valuable and will be of interest for scientists working in this area of plant biotechnology.

Hairy Root Cultures—A Versatile Tool With Multiple Applications

Abstract: Hairy roots derived from the infection of a plant by Rhizobium rhizogenes (previously referred to as Agrobacterium rhizogenes) bacteria, can be obtained from a wide variety of plants and allow the production of highly diverse molecules. Hairy roots are able to produce and secrete complex active glycoproteins from a large spectrum of organisms. They are also adequate to express plant natural biosynthesis pathways required to produce specialized metabolites and can benefit from the new genetic tools available to facilitate an optimized production of tailor-made molecules. This adaptability has positioned hairy root platforms as major biotechnological tools. Researchers and industries have contributed to their advancement, which represents new alternatives from classical systems to produce complex molecules. Now these expression systems are ready to be used by different industries like pharmaceutical, cosmetics, and food sectors due to the development of fully controlled large-scale bioreactors. This review aims to describe the evolution of hairy root generation and culture methods and to highlight the possibilities offered by hairy roots in terms of feasibility and perspectives.

Application of genetics and biotechnology for improving medicinal plants.

Abstract: Plant tissue culture has been used for conservation, micropropagation, and in planta overproduction of some pharma molecules of medicinal plants. New biotechnology-based breeding methods such as targeted genome editing methods are able to create custom-designed medicinal plants with different secondary metabolite profiles. For a long time, humans have used medicinal plants for therapeutic purposes and in food and other industries. Classical biotechnology techniques have been exploited in breeding medicinal plants. Now, it is time to apply faster biotechnology-based breeding methods (BBBMs) to these valuable plants. Assessment of the genetic diversity, conservation, proliferation, and overproduction are the main ways by which genetics and biotechnology can help to improve medicinal plants faster. Plant tissue culture (PTC) plays an important role as a platform to apply other BBBMs in medicinal plants. Agrobacterium-mediated gene transformation and artificial polyploidy induction are the main BBBMs that are directly dependent on PTC. Manageable regulation of endogens and/or transferred genes via engineered zinc-finger proteins or transcription activator-like effectors can help targeted manipulation of secondary metabolite pathways in medicinal plants. The next-generation sequencing techniques have great potential to study the genetic diversity of medicinal plants through restriction-site-associated DNA sequencing (RAD-seq) technique and also to identify the genes and enzymes that are involved in the biosynthetic pathway of secondary metabolites through precise transcriptome profiling (RNA-seq). The sequence-specific nucleases of transcription activator-like effector nucleases (TALENs), zinc-finger nucleases, and clustered regularly interspaced short palindromic repeats-associated (Cas) are the genome editing methods that can produce user-designed medicinal plants. These current targeted genome editing methods are able to manage plant synthetic biology and open new gates to medicinal plants to be introduced into appropriate industries.