Suprasanna Penna

... Suprasanna Penna.*, Manjunatha Benakanare Ramaswamy, Bapat Vishvas. Anant. ... In Ashwini Kumar, Shikha Roy eds, Plant Biotechnology & Its Applications in Tissue Culture., IK International, New Delhi, pp 54-61 Suprasanna P, Ganapathi, TR, Rao PS. 1995. ...

A protocol for direct somatic embryogenesis without an intervening callus phase was developed for sugar- cane (Saccharum spp. hybrids) using immature inflo- rescence segments. Murashige and Skoog (MS) medium supplemented with 0.5 mg/l naphthaleneacetic acid, 2.5 mg/l kinetin, 100 mg/l L-glutamine and 4% sucrose showed high frequency of somatic embryo develop- ment (54.09 ± ± 2.7%), with an average 7.72 ± ± 0.89 plants per explant. Embryo development was seen all over the cultured explants within four weeks of culture and the embryos germinated within a week upon transfer to basal MS medium without any growth regulators and all the plants grew normally in the greenhouse. This is a report on the induction of direct embryo- genesis from inflorescence segments in Indian sugar- cane. This method could be useful for regenerating large number of plants as well as provide a target ti s- sue for genetic transformation studies. SUGARCANE (Saccharum spp. hybrids) is a highly poly- ploid plant ...

A b s t r a c t Bananas and plantains are one of the major fruit crops and a staple food in the developing world. Most of the edible bananas are triploid, highly sterile and hence integration of in vitro techniques banana improvement becomes crucial. In this milieu, technique of somatic embryogenesis in combination with genetic manipulation, has become pertinent. In the present study, results are presented on developing embryogenic culture systems in banana. Immature Male Flowers (IMFs) of different banana cultivars (Ardhapuri, Basrai, Grande Naine, Lalkela, Mutheli and Shrimanti) were tested for callus induction on medium containing 2,4-D, IAA and NAA. In terms of callus induction from IMFs of AAA genomic group, Lalkela showed highest response (77.7%) followed by medium response in Shrimanti (52.2%), Basrai (51%), Grande Naine (42.5%), Ardhapuri (42%) and Mutheli (40%). Compared to this group, Safed Velchi (BB) was found to be highly responsive to IMF culture (70%) similar to Lalke...

In banana tissue cultures, the occurrence of dwarf off types is a common phenomenon and their detection become relevant. In this study, tissue culture derived (somaclonal) and radiation-induced off types in banana cultivars. Robusta and Giant Cavendish were analyzed using a SCAR-based molecular diagnostic technique. The dwarfs were initially characterized at maturity, by height, leaf shape, pseudostem height and other agronomic characters. At the molecular level, amplification with the SCAR primer resulted in an expected amplified fragment of 1500 bp in normal but not in the dwarf types. Further in a multiplex PCR, an internal positive control was included using primers for 18S rRNA which gave amplification in both the normal and dwarf types. This study shows that the dwarf off-types isolated through tissue culture and radiation-mutagenesis were true dwarfs, validated by using the dwarf-specific RAPD marker for banana.

Osmotic and oxidative stress responses to iso-osmotic (-0.4 Mpa) NaCl, PEG-6000 and mannitol stress were studied in 15-day old plants of three potato cultivars viz. 'Kufri Kufri Bahar' 'Jyoti' and 'Chandramukhi'. After 2-weeks of treatment, plants were analyzed for bio-chemical and physiological determinants of stress. Relative water content (RWC) and membrane damage rate (MDR) were significantly affected in all the cultivars in all the treatments. Decrease in RWC was significant in plants subjected to PEG while significant increase in MDR was observed in NaCl-treated plants. Among the treatments, NaCl treatment showed significant MDR (78.57%) over PEG (69.29%) and mannitol (62.90%) treatments. Proline, glycine betaine and total soluble sugar accumulation increased in the stressed plants than controls. Increased SOD activity was observed under NaCl stress compared to PEG/mannitol stress in all the cultivars. Comparison of different iso-osmotic stresses indica...

Amylases are well known for applications ranging from starch and food processes industry to medical applications. In the present study, the potential of banana peel was evaluated for α-amylase production using the fungal culture of Aspergillus niger NCIM 616 in solid submerged (SmF) and solid state (SSF) fermentation. The effect of different parameters, such as, substrate concentration, water content, layer thickness and external salt addition was studied in terms of the amylase activity. In SmF, 25% peel concentration was found optimum for the maximal amylase activity; while in SSF, 30% water content in the 3 cm thick substrate bed was optimum. The activity was also influenced by the addition of external salts and the combination of 1% NH 4 NO 3 with 0.5% CaCl 2 was found to have maximal effect. A comparative evaluation of two different fermentation systems showed 80% higher specific activity of α-amylase in SSF as compared to that in SmF, which clearly demonstrated the superiority...

... Sci. 86, 902–904. Kulkarni, VM, Suprasanna, P., Ganapathi, TR, Bapat, VA & Rao, PS (2004b) Differential effects of genome and cytokinins on shoot ... Murashige, T. & Skoog, F. (1962) A revised medium for rapid growth and bioassays with tobacco tissue culture. Physiol. ...

ABSTRACT Effect of plant growth regulators on morphogenesis was studied using callus derived from inflorescence segments of sugarcane cv. Co-91010 and CoC-671 cultured on MS medium supplemented with 2,4-D, malt extract, L-glutamine, casein hydroly sate and coconut water (CW). Comparison was made of different media combinations of CW (5,10%), kinetin (lmg/l), zeatin (0.5mg/l) andTDZ (0.5mg/l) to study callus growth and regeneration. Results showed that CW (5%) + zeatin (0.5mg/l) was more effective over other growth regulators for callus induction while CW 5% was found effective for the regeneration of healthy plants in cv. Co-91010. Different levels of proline and thioproline were tested on the induction of embryogenie callus and subsequent plant regeneration in var. CoC-671. Proline at 2.61M showed vigorous growth of embryogenie callus compared to thioproline. Plants regenerated were hardened and grown in the green house to maturity.

... Acknowledgements. Authors would like to thank Dr. Sudhakar Srivastava, NABTD for giving critical suggestions during manuscript preparation. Ms. Esha Mathur is also gratefully acknowledged for the assistance provided during the course of experiment. References. ...

ABSTRACT Salt stress, considered as one of the major factors, decreases crop productivity world-wide and hence, investigations are being made to understand the cellular basis of salt tolerance in plants. In our earlier studies, maintenance of redox homeostasis and energetics were found as key determinants of salt tolerance in a halophyte Sesuvium portulacastrum (high salt accumulator). The redox homeostasis is defined as integrated ratio of different redox couples present inside the cell. In recent years, it has also been proposed as general stress response regulator in plants, bacteria as well as animals. In view of this, present study was performed to compare responses of redox state and energetics of S. portulacastrum with a glycophyte Brassica juncea (low salt accumulator). The data revealed activation of antioxidant defense in S. portulacastrum which either avoided or delayed the accumulation of different reactive oxygen species (ROS). In contrast, due to the lack of co-ordination, although the non-enzymatic antioxidants were increased, significant oxidative damage was seen in B. juncea. Further, the decreased NADPH oxidase activity suggested that basal redox signaling was also affected in B. juncea. In order to correlate these changes with chloroplastic and mitochondrial electron transport chain, NADP/NADPH and NAD/NADH ratios were measured. The NADP/NADPH ratio suggested that the process of photosynthesis was minimally affected in S. portulacastrum which might have contributed to its lower level of ROS under salt stress. The comparatively lower NAD/NADH and ATP/ADP ratios in S. portulacastrum as compared to B. juncea indicated the active and better utilization of energy generated to support different processes associated with salt tolerance. Thus, the findings suggest that co-ordinated regulation of antioxidant defense to avoid oxidative damage and proper utilization of energy are the key determinants of salt-tolerance in plants.

Salt-stress-induced alterations in osmotic, ionic, and redox responses were studied in the early period of treatment (30 min to 5 days) in seedlings of Brassica juncea L. Roots and shoots under mild (50 mM) and severe (250 mM) NaCl stress were analyzed for growth, oxidative stress, osmolyte accumulation, antioxidant defense, and redox state. Growth reduction was less pronounced in the early time period of salt stress while oxidative damage increased linearly and in a sustained manner under severe stress up to 6 h. An early and transient reactive oxygen species (ROS) burst, as evidenced by superoxide and hydrogen peroxide level was observed, followed by activation of enzymatic antioxidant system (GPX, SOD, CAT, and GR) in both root and shoot. The enzymatic activity was not affected much under mild stress particularly at early phase; however, severe stress induced a significant increase in the activity of antioxidant enzymes. Root ascorbate was progressively accumulated, and its redox state maintained in the early time phase of treatment under mild stress while increase in root and shoot glutathione content was recorded under mild stress at 5 days when the active ascorbate pool decreased. While early period of salt stress showed significant Na(+) accumulation over control, plants subjected to mild stress measured less Na(+) accumulation up to 5 days compared to severely stressed plants. The results showed an early induction of differential responses to salt stress in roots and shoots of Brassica which include growth limitations, reduced relative water content, increased osmolytes, redox state, and antioxidant system, and a significant Na(+) increase. The results also indicate that roots and shoots may have distinct mechanisms of responses to salt stress.

Arsenic (As) is a ubiquitously present environmental carcinogen that enters into the human food chain through rice grains. In our previous research, the application of thiourea (TU; a non-physiological thiol based ROS scavenger) has been demonstrated to enhance salt and UV stress tolerance as well as the crop yield under field conditions. These effects were associated with the ability of TU to maintain plant redox homeostasis. Since As stress also induces redox imbalance, the present research was initiated to evaluate the efficiency of TU in regulating As tolerance/accumulation in rice. The supplementation of TU (75 μM) to As(V) (25 μM) improved the root growth and also reduced the As concentration by 56% in the aerial parts, which could be attributed to significant downregulation of the Lsi2 transporter responsible for the translocation of As from root to shoot. The fact that these effects were not due to direct interaction between As and TU was confirmed from complexation studies ...

Plants were regenerated from encapsulated shoot tips of banana. Shoot tips (ca 4 mm) isolated from multiple shoot cultures of banana cv. Basrai were encapsulated in 3% sodium alginate containing different gel matrices. The encapsulated shoot tips regenerated in vitro on different substrates. Use of White's medium resulted in 100% conversion of encapsulated shoot tips into plantlets. The plantlets were successfully established in soil.

Arsenic (As) contamination of the environment has emerged as a serious problem. Consequently, there is an urge to understand plants' responses to As. The analysis of various hypertolerant and hyperaccumulator plants and comparison of their responses with non-tolerant and nonaccumulators have provided valuable information about the mechanisms of As tolerance and detoxification. Therefore, we understand why most of the pteridophytes are able to hyperacumulate As, why it is difficult to find hyperaccumulators among angiosperms and why rice is able to translocate As to its grains more efficiently than any other cereal crop. This information can be employed to generate As hyperaccumulators in angiosperms and to develop safe cultivars of rice for human consumption through biotechnological approaches. Although measurable success, in terms of application in the field, has so far not been achieved, transgenic research has yielded promising results, which shed light on the approaches to b...

Abiotic stresses including salinity are the major constraints to crop production. In this regard, the use of thiourea (TU) in imparting salinity-stress tolerance to Indian mustard (Brassica juncea) has been demonstrated earlier. To gain an insight into the mechanism of TU action, various molecular and biochemical studies were conducted. Microarray analysis was performed in seeds subjected to distilled water (control), 1 m NaCl, 1 m NaCl + 6·5 mm TU and 6·5 mm TU alone for 1 h. Real-time PCR validation of selected genes and biochemical studies were conducted under similar treatments at 1 h and 6 h. The microarray analysis revealed a differential expression profile of 33 genes in NaCl- and NaCl + TU-treated seeds, most of which are established markers of stress tolerance. The temporal regulation of eight selected genes by real-time PCR indicated their early and co-ordinated induction at 1 h in NaCl + TU only. Besides, NaCl + TU-treated seeds also maintained a higher level of abscisic ...

Drought-tolerant and drought-susceptible genotypes of sorghum (Sorghum bicolor L. Monech) were analyzed by the energy-dispersive X-ray fluorescence (EDXRF) technique to study the correlation of trace elements with drought-tolerance capacities. Samples prepared from mature seeds, young seedlings, and old plants were analyzed using a 109Cd radioisotope source and a Si(Li) semiconductor detector of resolution 170 eV for 5.9-keV MnKalpha X-rays. Elements such as K, Fe, Cu, Zn, Rb and Sr and Y were found to be present in varying concentrations in different samples. The trace element profile studied in the seeds of 11 genotypes and in seedlings (young and old) of 4 sorghum genotypes showed considerable variation. The genotype Arfa Gadamak (AG) showed a distinct presence of a high level of Zn in its young seedling. It was observed that in most of the genotypes (seeds), K and Fe concentrations were more in the tolerant genotype as compared to the susceptible type. The concentration of Fe de...

In the past two to three decades, great progress has been achieved in the field of plant genetic manipulation. This progress is based on fine-tuning gene transfer methods, selection of transformed cells and regulation of transgene expression. Transgenic plant production requires selectable marker genes that enable the selection of transformed cells, tissue and plants. The most used are those that exhibit resistance to antibiotics or herbicides. Although this type of selection is routinely practiced, there are perceived risks in the deployment of transgenic plants containing these markers. A number of strategies have emerged on the development of alternate selection systems referred to as positive selection and marker-free systems. Transgenes that permit plant cells to utilize new carbon sources are being employed in transformation research. Current research on development of novel selection methods in transgenics is growing rapidly and its application is being tested in different plant species.

Glucosinolates, found principally in the plant order Brassicales, are modulated by different post-harvest processing operations. Among these, ionizing radiation, a non-thermal process, has gained considerable interest for ensuring food security and safety. In gamma-irradiated cabbage, enhanced sinigrin, a major glucosinolate, has been reported. However, the molecular basis of such a radiation induced effect is not known. Herein, the effect of radiation processing on the expression of glucosinolate biosynthetic genes was investigated. RT-PCR based expression analysis of seven glucosinolate biosynthetic pathway genes (MYB28, CYP79F1, CYP83A1, SUR1, UGT74B1, SOT18 and TGG1) showed that CYP83A1, MYB28, UGT74B1, CYP79F1 and SUR1 were up-regulated in irradiated cabbage. The content of jasmonates, signalling molecules involved in glucosinolate induction was, however, unaffected in irradiated cabbage suggesting their non-involvement in glucosinolate induction during radiation processing. This is the first report on the effect of gamma irradiation on the expression of glucosinolate biosynthetic genes in vegetables.

Radiation induced and somaclonal variants of sugarcane cv. COC671 were selected in vitro on different sub-lethal doses of salt (NaC1) and polyethylene glycol 8000 (PEG). The genetic variability among the variants was analyzed using Random Amplified Polymorphic DNA ( ...

ABSTRACT Gamma-ray-induced mutagenesis and in vitro selection of sugarcane (Saccharum officinarum L. Lam.) plants tolerant to NaCl was achieved using embryogenic calli of sugarcane var. Co740. Sensitivity to gamma radiation and NaCl was studied in vitro in embryogenic calli followed by characterization and evaluation of mutant clones. The results indicated that callus growth and plant regeneration were significantly affected by radiation dose (0, 10, 20, 30, 40, 50, 60, 70, or 80 Gy 60Co gamma rays) as well as NaCl exposure (0, 50, 100, 150, 200, or 250 mM). Salt tolerance was achieved by culturing irradiated callus on selection medium with different NaCl concentrations through stepwise in vitro selection. Salt-selected embryogenic callus lines were then analyzed for proline, glycine betaine, Na+, and K+ contents. Salt-selected plants were grown to maturity, and their agronomic performance was evaluated under normal and saline conditions. Twenty-four mutant clones were characterized for proline, glycine betaine, Na+, and K+ contents. The mutant clones exhibited improved sugar yield with increments in Brix%, number of millable canes, girth, and yield. The results suggest that in vitro culture and induced mutagenesis offer an effective way to enhance the genetic variation in sugarcane.

Abstract Abiotic stress has become a challenge to food security due to occurrences of climate change and environmental degradation. Plants initiate molecular, cellular and physiological changes to respond and adapt to various types of abiotic stress. Understanding of plant response mechanisms will aid in strategies aimed at improving stress tolerance in crop plants. One of the most common and early symptoms associated with these stresses is the disturbance in plant-water homeostasis, which is regulated by a group of proteins called "aquaporins". Aquaporins constitute a small family of proteins which are classified further on the basis of their localization, such as plasma membrane intrinsic proteins, tonoplast intrinsic proteins, nodulin26-like intrinsic proteins (initially identified in symbiosomes of legumes but also found in the plasma membrane and endoplasmic reticulum), small basic intrinsic proteins localized in ER (endoplasmic reticulum) and X intrinsic proteins present in plasma membrane. Apart from water, aquaporins are also known to transport CO2, H2O2, urea, ammonia, silicic acid, arsenite and wide range of small uncharged solutes. Besides, aquaporins also function to modulate abiotic stress-induced signaling. Such kind of versatile functions has made aquaporins a suitable candidate for development of transgenic plants with increased tolerance toward different abiotic stress. Toward this endeavor, the present review describes the versatile functions of aquaporins in water uptake, nutrient balancing, long-distance signal transfer, nutrient/heavy metal acquisition and seed development. Various functional genomic studies showing the potential of specific aquaporin isoforms for enhancing plant abiotic stress tolerance are summarized and future research directions are given to design stress-tolerant crops.