Satyesh Chandra Roy

Bio: Satyesh Chandra Roy is an academic researcher from University of Calcutta. The author has contributed to research in topics: Callus & Explant culture. The author has an hindex of 14, co-authored 38 publications receiving 801 citations.

Genetic stability of three economically important micropropagated banana (Musa spp.) cultivars of lower Indo-Gangetic plains, as assessed by RAPD and ISSR markers

Abstract: An efficient micropropagation protocol produced large number of plants of the three elite banana (Musa spp.) cultivars Robusta (AAA), Giant Governor (AAA) and Martaman (AAB) from shoot tip meristem. The genetic relationships and fidelity among the cultivars and micropropagated plants as assessed by random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers, revealed three somaclonal variants from Robusta and three from Giant Governor. A total of 5330 RAPD and 2741 ISSR fragments were generated with 21 RAPD and 12 ISSR primers in micropropagated plants. The percentage of polymorphic loci by RAPD and ISSR were found to be 1.75, 5.08 in Robusta and 0.83, 5.0 in Giant Governor respectively. Among the two marker systems used, ISSR fingerprinting detected more polymorphism than RAPD in Robusta and Giant Governor with most of the primers showing similar fingerprinting profile, whereas Martaman revealed complete genetic stability.

Transgenic rice expressing Allium sativum leaf lectin with enhanced resistance against sap-sucking insect pests.

Abstract: Mannose binding Allium sativum leaf agglutinin (ASAL) has been shown to be antifeedant and insecticidal against sap-sucking insects. In the present investigation, ASAL coding sequence was expressed under the control of CaMV35S promoter in a chimeric gene cassette containing plant selection marker, hpt and gusA reporter gene of pCAMBIA1301 binary vector in an elite indica rice cv. IR64. Many fertile transgenic plants were generated using scutellar calli as initial explants through Agrobacterium-mediated transformation technology. GUS activity was observed in selected calli and in mature plants. Transformation frequency was calculated to be ~12.1%±0.351 (mean ± SE). Southern blot analyses revealed the integration of ASAL gene into rice genome with a predominant single copy insertion. Transgene localization was detected on chromosomes of transformed plants using PRINS and C-PRINS techniques. Northern and western blot analyses determined the expression of transgene in transformed lines. ELISA analyses estimated ASAL expression up to 0.72 and 0.67% of total soluble protein in T0 and T1 plants, respectively. Survival and fecundity of brown planthopper and green leafhopper were reduced to 36% (P<0.01), 32% (P<0.05) and 40.5, 29.5% (P<0.001), respectively, when tested on selected plants in comparison to control plants. Specific binding of expressed ASAL to receptor proteins of insect gut was analysed. Analysis of T1 progenies confirmed the inheritance of the transgenes. Thus, ASAL promises to be a potential component in insect resistance rice breeding programme.

In vitro regeneration and micropropagation of Aloe vera L.

Abstract: Rapid propagation by the formation of shoots from calli of Aloe vera was obtained in the present investigation. Callus formation was induced in stem segments from young axillary shoots grown on the underground rhizomatous stem. The use of polyvinylpyrrolidone (PVP) in the nutrient media reduced the secretion of phenolic substances from the explant. Murashige and Skoog's basal medium containing 1 mg l−1 2,4-dichlorophenoxyacetic acid and 0.2 mg l−1 kinetin gave the best callus induction. Shoots were initiated from the calli with reduced 2,4-D and increased kinetin concentration.

Genetic Diversity of Amaranthus Species from the Indo-Gangetic Plains Revealed by RAPD Analysis Leading to the Development of Ecotype-Specific SCAR Marker

Abstract: Genetic diversity and relationships among 6 Amaranthus species from 8 phytogeographic regions of the Indo-Gangetic plains were analyzed using a random amplified polymorphic DNA (RAPD) marker RAPD primers yielded a total of 262 amplicons, ranging from ;250 to ;3000 bp in size with an average of 131 amplicons per primer, of which 254 amplicons (9694%) were polymorphic The genetic similarity coefficient among all the Amaranthus species ranged from 016 to 097 with a mean similarity coefficient of 056, indicating that variation existed in the genetic diversity of different populations In the unweighted pair group method with arithmetic average dendrogram, populations of the same species clustered together A unique 1371-bp RAPD band specific for Amaranthus gangeticus (syn tricolor) of a particular phytogeographic region was converted to a sequenced characterized amplified region (SCAR) marker The translated marker sequence showed homology with hemagglutinin protein This SCAR marker is potentially useful for germplasm conservation and identification of amaranth ecotype

Somaclonal variation — a novel source of variability from cell cultures for plant improvement

Abstract: It is concluded from a review of the literature that plant cell culture itself generates genetic variability (somaclonal variation). Extensive examples are discussed of such variation in culture subclones and in regenerated plants (somaclones). A number of possible mechanisms for the origin of this phenomenon are considered. It is argued that this variation already is proving to be of significance for plant improvement. In particular the phenomenon may be employed to enhance the exchange required in sexual hybrids for the introgression of desirable alien genes into a crop species. It may also be used to generate variants of a commercial cultivar in high frequency without hybridizing to other genotypes.

Mechanisms of plant defense against insect herbivores

Abstract: Plants respond to herbivory through various morphological, biochemicals, and molecular mechanisms to counter/offset the effects of herbivore attack. The biochemical mechanisms of defense against the herbivores are wide-ranging, highly dynamic, and are mediated both by direct and indirect defenses. The defensive compounds are either produced constitutively or in response to plant damage, and affect feeding, growth, and survival of herbivores. In addition, plants also release volatile organic compounds that attract the natural enemies of the herbivores. These strategies either act independently or in conjunction with each other. However, our understanding of these defensive mechanisms is still limited. Induced resistance could be exploited as an important tool for the pest management to minimize the amounts of insecticides used for pest control. Host plant resistance to insects, particularly, induced resistance, can also be manipulated with the use of chemical elicitors of secondary metabolites, which confer resistance to insects. By understanding the mechanisms of induced resistance, we can predict the herbivores that are likely to be affected by induced responses. The elicitors of induced responses can be sprayed on crop plants to build up the natural defense system against damage caused by herbivores. The induced responses can also be engineered genetically, so that the defensive compounds are constitutively produced in plants against are challenged by the herbivory. Induced resistance can be exploited for developing crop cultivars, which readily produce the inducible response upon mild infestation, and can act as one of components of integrated pest management for sustainable crop production.

Somaclonal variation in plants: causes and detection methods

Abstract: Plant tissue culture has become one of the fundamental tools of plant science research. It is extensively employed in the production, conservation and improvement of plant resources. The presence of somaclonal variation in populations derived from tissue culture is affecting the use of tissue culture negatively and has remained a major problem. Conversely, it is a source of new desirable clones/variants with better agronomic traits. In this review, we summarize the possible causes, detection methods and desirability of variants. Somaclonal variation is one of the most researched and reviewed topics. Hence, we restricted ourselves to outlining various examples which may be used as important references for researchers who intend to identify and/or characterize somaclonal variants while using tissue culture for research and production. Emphasis is placed on the negative effects of somaclonal variation. However, this review also includes examples of some useful variants generated as a result of somaclonal variation.

Domestication, Genomics and the Future for Banana

Abstract: We thank the Generation Challenge Programme for support, and some work was in collaborations under an IAEA/FAO Coordinated Research Project. We are extremely grateful to our many collaborators on the banana projects. Funding to pay the Open Access publication charges for this article was provided by the OECD.

From forest to field: Perennial fruit crop domestication

Abstract: PREMISE OF THE STUDY Archaeological and genetic analyses of seed-propagated annual crops have greatly advanced our understanding of plant domestication and evolution. Comparatively little is known about perennial plant domestication, a relevant topic for understanding how genes and genomes evolve in long-lived species, and how perennials respond to selection pressures operating on a relatively short time scale. Here, we focus on long-lived perennial crops (mainly trees and other woody plants) grown for their fruits. KEY RESULTS We reviewed (1) the basic biology of long-lived perennials, setting the stage for perennial domestication by considering how these species evolve in nature; (2) the suite of morphological features associated with perennial fruit crops undergoing domestication; (3) the origins and evolution of domesticated perennials grown for their fruits; and (4) the genetic basis of domestication in perennial fruit crops. CONCLUSIONS Long-lived perennials have lengthy juvenile phases, extensive outcrossing, widespread hybridization, and limited population structure. Under domestication, these features, combined with clonal propagation, multiple origins, and ongoing crop-wild gene flow, contribute to mild domestication bottlenecks in perennial fruit crops. Morphological changes under domestication have many parallels to annual crops, but with key differences for mating system evolution and mode of reproduction. Quantitative trait loci associated with domestication traits in perennials are mainly of minor effect and may not be stable across years. Future studies that take advantage of genomic approaches and consider demographic history will elucidate the genetics of agriculturally and ecologically important traits in perennial fruit crops and their wild relatives.