Browsing by Author "Smita Kumar"

Now showing 1 - 4 of 4

Comprehensive analysis of regulatory elements of the promoters of rice sulfate transporter gene family and functional characterization of OsSul1;1 promoter under different metal stress
(Taylor and Francis Inc., 2015) Smita Kumar; Mehar Hasan Asif; Debasis Chakrabarty; Rudra Deo Tripathi; Rama Shanker Dubey; Prabodh Kumar Trivedi
Adverse environmental conditions including heavy metal stress impose severe effects on the plant growth and development limiting productivity and yield. Studies demonstrated that changes in genome-wide expression modulate various biochemical processes and molecular components in response to heavy metal stress in plants. Some of the key components involved in such a regulation are the transcription initiation machinery, nucleotide sequence of promoters and presence of cis-acting elements. Therefore, identification of the putative cis-acting DNA sequences involved in gene regulation and functional characterization of promoters are important steps in understanding response of plants to heavy metal stress. In this study, comprehensive analysis of the proximal promoters of members of rice sulfate transporter gene family which is an essential component of stress response has been carried out. Analysis suggests presence of various common stress related cis-acting elements in the promoters of members of this gene family. In addition, transcriptional regulation of the arsenic-responsive high affinity sulfate transporter, OsSul1;1, has been studied through development of Arabidopsis transgenic lines expressing reporter gene encoding b-glucuronidase under the control of OsSul1;1 promoter. Analysis of the transgenic lines suggests differential response of the OsSul1;1 promoter to various heavy metals as well as other abiotic stresses. © 2015 Taylor & Francis Group, LLC.
Differential Expression of Rice Lambda Class GST Gene Family Members During Plant Growth, Development, and in Response to Stress Conditions
(2013) Smita Kumar; Mehar Hasan Asif; Debasis Chakrabarty; Rudra Deo Tripathi; Rama Shanker Dubey; Prabodh Kumar Trivedi
Glutathione S-transferases (GSTs; EC 2.5.1.18) are members of an isozyme family and catalyze the conjugation of the reduced tripeptide glutathione to a variety of hydrophobic and electrophilic substrates. Though members of different classes of the GST superfamily have been identified and characterized from many plant species including rice, no detailed information is available for the Lambda class gene family in rice. In this study, a genome-wide analysis was carried out to investigate expression patterns of three Lambda class GST members of rice including OsGSTL1, OsGSTL2 and OsGSTL3 in seedlings, at different growth and developmental stages as well as in response to various biotic and abiotic stresses. Expression analysis using microarray datasets and quantitative real-time reverse transcriptase polymerase chain reaction suggests that this gene family express differentially in various tissues, in response to hormones and during different biotic and abiotic stresses including heavy metals, cold, drought and salt stress. Massively Parallel Signature Sequencing (MPSS) analysis also showed differential expression of OsGSTLs during plant growth and development and under different stresses. Out of three members, maximum expression of OsGSTL2 was observed for the MPSS libraries in comparison to other members. We conclude that members of rice Lambda class GST family play an important role in plant growth and development and in combating different biotic and abiotic stresses. © 2012 Springer Science+Business Media New York.
Expression of a rice Lambda class of glutathione S-transferase, OsGSTL2, in Arabidopsis provides tolerance to heavy metal and other abiotic stresses
(2013) Smita Kumar; Mehar Hasan Asif; Debasis Chakrabarty; Rudra Deo Tripathi; Rama Shanker Dubey; Prabodh Kumar Trivedi
Global industrial growth has contaminated the soil and water with many hazardous compounds, including heavy metals. These heavy metals are not only toxic to plants but also cause severe human health hazards when leach out into food chain. One of the approaches employed for the decontamination of environment includes identification and overexpression of genes involved in the detoxification mechanism of plants. Glutathione S-transferases (GSTs) are a superfamily of enzymes, principally known for their role in detoxification reactions. Different classes of GSTs have been used to develop plants with improved detoxification mechanism, but not much information is available for Lambda class of GSTs. Here, we studied expression of OsGSTLs in different rice genotypes under arsenic stress. The study suggests differential expression of these genes in arsenic sensitive and tolerant genotypes. Further, the role of one member of Lambda class OsGSTL2 was studied by expressing in heterologous system, Arabidopsis. Transgenic lines developed were analysed for their response to different abiotic stresses including heavy metals. Analysis suggests that OsGSTL2 provides tolerance for heavy metals and other abiotic stresses like cold, osmotic stress and salt. We conclude that OsGSTLs can be utilized for developing plant varieties tolerant to different abiotic stresses including heavy metals. © 2013 Elsevier B.V.
Omics and biotechnology of arsenic stress and detoxification in plants: Current updates and prospective
(Elsevier Ltd, 2015) Smita Kumar; Rama Shanker Dubey; Rudra Deo Tripathi; Debasis Chakrabarty; Prabodh Kumar Trivedi
Arsenic (As), a naturally occurring metallic element, is a dreadful health hazard to millions of people across the globe. Arsenic is present in low amount in the environment and originates from anthropogenic impact and geogenic sources. The presence of As in groundwater used for irrigation is a worldwide problem as it affects crop productivity, accumulates to different tissues and contaminates food chain. The consumption of As contaminated water or food products leads to several diseases and even death. Recently, studies have been carried out to explore the biochemical and molecular mechanisms which contribute to As toxicity, accumulation, detoxification and tolerance acquisition in plants. This information has led to the development of the biotechnological tools for developing plants with modulated As tolerance and detoxification to safeguard cellular and genetic integrity as well as to minimize food chain contamination. This review aims to provide current updates about the biochemical and molecular networks involved in As uptake by plants and the recent developments in the area of functional genomics in terms of developing As tolerant and low As accumulating plants. © 2014 Elsevier Ltd.