Sukumar Gupta

Bio: Sukumar Gupta is an academic researcher from Bose Institute. The author has contributed to research in topics: Callus & Kinetin. The author has an hindex of 12, co-authored 17 publications receiving 321 citations.

Effects of salt and osmotic shocks on unadapted and adapted callus lines of tobacco

Abstract: Growth, viability and proline content of adapted and unadapted calluses of Nicotiana tabacum L. var. Jayasri, affected due to osmotic stresses and particularly to stress-shocks treated with different osmotica like NaCl (ionic-penetrating), mannitol (non-ionic-penetrating) and polyethylene glycol, (PEG) (non-ionic-non penetrating) were studied to evaluate the physiological differences of stress effects. The tissues adapted to a low concentration of NaCl (85 mM) showed low growth with high proline content compared to the tissues adapted to a low concentration of mannitol (165 mM). Proline content was similar in tissues adapted to high concentrations of NaCl (171 mM) and mannitol (329 mM) but growth in the latter case was relatively low. Growth and viability were subsequently correlated with the pattern of retention in or diffusion of proline out of the tissues after shock-treatments. The loss of tissue viability of the adapted calluses was comparatively less than the unadapted callus even after shock-treatments with 1282 mM NaCl and 823 mM mannitol. The former calluses retained the capability of regrowth though at a slow rate. Such adapted tissues also retained more proline. The mannitol-adapted tissues, when shocked with PEG (200 g l-1), showed low viability with more diffusion and a very little retention of proline while, in the unadapted tissue, all the proline was leached out. The results indicated that the effects of different osmotica on plant tissue varied depending upon the physico-chemical nature of the compounds used as stress-inducing-agents, and retention and diffusion of proline was altered when the tissues were shocked with high concentrations of all these compounds.

In vitro selection and physiological characterization of NaCl- and mannitol-adapted callus lines in Brassica juncea

Abstract: Na Cl (salt)- and mannitol (drought)- tolerant callue lines of Brassica juncea (L) Czern. Var. RW-85-59 were isolated by a plated cell suspension culture technique against 43 mM NaCl and 165 mM mannitol, respectively. Callus lines, adapted to a high concentration of Na Cl (171 mM) and mannitol (329 mM) were then established bv direct adaptation procedures. In the initial passages, the calluses showed severe reduction in tissue growth when grown on NaCl/mannitol-containing media but growth of adapted calluses recovered and was sustainable in the subsequent passages. Adapted calluses showed considerable accumulation of free proline in NaCl-/mannitol- containing media compared to the control callus grown on stress-free medium. A significant increase of intensity of one particular acid phosphatase isozymic band in the adapted calluses, irrespective of NaCl or mannitol stress, indicated that it may be used as an osmotic stress-marker in this system. Short-term salt/osmotic-shock-treatment with high concentrations of osmotica revealed that only the adapted lines retained the maximum amount of free proline within the cells for osmoregulation. This response probably helped the cells to restore their normal growth when the stress was withdrawn.

Plant regeneration of salt adapted callus of indica rice (var. Basmati 370) in saline conditions

Abstract: NaCl adapted callus of a salt sensitive scented indica variety of rice (Oryza sativa var Basmati 370) showed 55% regeneration in culture medium supplemented with IAA and kinetin Regeneration was low in 85 mM NaCl but a concentration of 128 mM was inhibitory to regeneration SEM study revealed organogenesis and somatic embryogenesis from the same callus The rate of survival and endogenous free proline content of the plants regenerated from the NaCl adapted callus was significantly higher than for those obtained from unadapted callus in liquid maintenance media supplemented with NaCl

Micropropagation of Tectona grandis: assessment of genetic fidelity

Abstract: Random amplified polymorphic DNA (RAPD) markers were used to analyze genetic fidelity of micropropagated teak (Tectona grandis L.) clones with respect to subcultural passage. Of the twenty primers screened, no variation in RAPD profiles was noticed in the in vitro clones of fifth, tenth, fifteenth and twentieth passage in comparison to the in vivo mother plants. Only one micropropagated plant of twenty-fifth subcultural passage, however, differed from the in vivo ones. It revealed the appearance of a new polymorphic DNA fragment (molecular mass 379 kb) in case of primer OPB-08. This primer, manifesting detectable variation, may be utilized as a diagnostic marker for assessing genetic fidelity of micropropagted teak plants.

Embryogenesis and Differentiation in Nigella sativa Leaf Callus in vitro

Abstract: Embryogenesis occurred in Nigella sativa L. (Fam. Ranunculaceae) leaf callus tissue when coconut milk was replaced from the Murashige and Skoog's (MS) medium by casein hydrolysate. On MS + IAA (0.5 mg/l) + casein hydrolysate (100 and 500 mg/l) medium, tissue gained a capacity of growing embryoids for a pro-longed culture period. At a concentration of 1000 mg/l casein hydrolysate suppressed the differentiating capacity after the fifth subculture. 2.4-D and kinetin had inhibitory effects on morphogenesis. Histology of the differentiated tissue revealed that the origin of roots, shoot buds and leaves were from groups of meristematic cells whereas embryoids were initiated by the repeated division of a single cell.

Roles of glycine betaine and proline in improving plant abiotic stress resistance

Abstract: Glycine betaine (GB) and proline are two major organic osmolytes that accumulate in a variety of plant species in response to environmental stresses such as drought, salinity, extreme temperatures, UV radiation and heavy metals. Although their actual roles in plant osmotolerance remain controversial, both compounds are thought to have positive effects on enzyme and membrane integrity along with adaptive roles in mediating osmotic adjustment in plants grown under stress conditions. While many studies have indicated a positive relationship between accumulation of GB and proline and plant stress tolerance, some have argued that the increase in their concentrations under stress is a product of, and not an adaptive response to stress. In this article, we review and discuss the evidence supporting each of these arguments. As not all plant species are capable of natural production or accumulation of these compounds in response to stress, extensive research has been conducted examining various approaches to introduce them into plants. Genetically-engineered plants containing transgenes for production of GB or proline have thus far faced with the limitation of being unable to produce sufficient amounts of these compounds to ameliorate stress effects. An alternative “shot-gun” approach of exogenous application of GB or proline to plants under stress conditions, however, has gained some attention. A review of the literature indicates that in many, but not all, plant species such applications lead to significant increases in growth and final crop yield under environmental stresses. In this review article, numerous examples of successful application of these compounds to improve plant stress tolerance are presented. However, to streamline useful and economic applications of these compounds, further investigations are needed to determine the most effective concentrations and number of applications as well as the most responsive growth stage(s) of the plant. All these factors may vary from species to species. Furthermore, a better understanding of the mechanisms of action of exogenously applied GB and proline is expected to aid their effective utilization in crop production in stress environments.

Role of proline under changing environments: a review.

Abstract: When exposed to stressful conditions, plants accumulate an array of metabolites, particularly amino acids. Amino acids have traditionally been considered as precursors to and constituents of proteins, and play an important role in plant metabolism and development. A large body of data suggests a positive correlation between proline accumulation and plant stress. Proline, an amino acid, plays a highly beneficial role in plants exposed to various stress conditions. Besides acting as an excellent osmolyte, proline plays three major roles during stress, i.e., as a metal chelator, an antioxidative defense molecule and a signaling molecule. Review of the literature indicates that a stressful environment results in an overproduction of proline in plants which in turn imparts stress tolerance by maintaining cell turgor or osmotic balance; stabilizing membranes thereby preventing electrolyte leakage; and bringing concentrations of reactive oxygen species (ROS) within normal ranges, thus preventing oxidative burst ...

Some Prospective Strategies for Improving Crop Salt Tolerance

Abstract: Soil salinity is a major environmental constraint to crop productivity worldwide. The “biological” approach to this problem focuses on the management, exploitation, or development of plants able to thrive on salt‐affected soils. This chapter reviews strategies by which plants can be enabled to grow on saline soils. The first strategy is to prime seeds before planting by treating them with inorganic or organic chemicals and/or with high or low temperatures. The second strategy involves exogenous application of organic chemicals, such as glycine betaine, proline, or plant growth regulators, or inorganic chemicals to plants under salinity stress. Considerable improvements in growth and yield have been reported in a number of crops using these approaches. The third strategy is to employ selection and breeding. Major efforts have been made to develop salt‐tolerant lines or cultivars of crops using conventional plant breeding. However, the complexity of the tolerance mechanisms, lack of selection criteria, and variation in responses of plants at different developmental stages have resulted in only limited success. The emphases for developing salt‐tolerant lines/cultivars are now on marker‐assisted breeding and genetic transformation. The development of salt‐tolerant transgenic plants is still at an early stage but may become increasingly more effective as better knowledge of the complex mechanisms involved in plant salt tolerance is acquired. Furthermore, the rapid expansion in knowledge on genomics and proteomics will undoubtedly accelerate the transgenic and molecular breeding approaches However, to date, there are few conclusive reports indicating successful performance of transgenic cultivars under natural stressful environments.

In vitro manipulation and propagation of medicinal plants

Abstract: Well developed techniques are currently available to help growers meet the demand of the pharmaceutical industry in the next century. These protocols are designed to provide optimal levels of carbohydrates, organic compounds (vitamins), mineral nutrients, environmental factors (e.g. light, gaseous environment, temperature, and humidity) and growth regulators required to obtain high regeneration rates of many plant species in vitro and thereby facilitate commercially viable micropropagation. Well-defined cell culture methods have also been developed for the production of several important secondary products. An overview of the regeneration of medicinal plants by direct and indirect organogenesis and by somatic embryogenesis from various types of explants is presented, and the use of these techniques combined with other biotechnological approaches to improve medicinal plants through somaclonal variation and genetic transformation is reviewed.

Developing stress tolerant plants through in vitro selection—An overview of the recent progress

Abstract: Biotic and abiotic stresses impose a major threat to agriculture Therefore, the efforts to develop stress-tolerant plants are of immense importance to increase crop productivity In recent years, tissue culture based in vitro selection has emerged as a feasible and cost-effective tool for developing stress-tolerant plants Plants tolerant to both the biotic and the abiotic stresses can be acquired by applying the selecting agents such as NaCl (for salt tolerance), PEG or mannitol (for drought tolerance) and pathogen culture filtrate, phytotoxin or pathogen itself (for disease resistance) in the culture media Only the explants capable of sustaining such environments survive in the long run and are selected In vitro selection is based on the induction of genetic variation among cells, tissues and/or organs in cultured and regenerated plants The selection of somaclonal variations appearing in the regenerated plants may be genetically stable and useful in crop improvement This review focuses on the progress made towards the development of stress-tolerant lines through tissue culture based in vitro selection Plants have evolved many biochemical and molecular mechanisms to survive under stress conditions The mechanisms of ROS (reaction oxygen species) generation and removal in plants under biotic and abiotic stress conditions have also been reviewed