Institutional Publications

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    Expression of TaNCL2-A ameliorates cadmium toxicity by increasing calcium and enzymatic antioxidants activities in arabidopsis
    (Elsevier B.V., 2023) Shumayla; Tyagi, Shivi; Sharma, Yashraaj; Madhu; Sharma, Alok; Pandey, Ashutosh; Singh, Kashmir; Upadhyay, Santosh Kumar
    Cadmium (Cd) is a heavy metal that occurs naturally in the environment and is toxic to both animals and plants. The impact of Cd toxicity is shown to be reduced by the exogenous application of calcium (Ca) in crop plants. The sodium/calcium exchanger-like (NCL) protein is involved in Ca enrichment in the cytoplasm by transporting it from the vacuole in the exchange of cytosolic sodium (Na). However, it has not been utilized to ameliorate the Cd toxicity, to date. An elevated expression of TaNCL2-A gene in the root and shoot tissues of bread wheat seedlings, and a higher growth rate of recombinant yeast cells, suggested its role in Cd stress response. The TaNCL2-A expressing transgenic Arabidopsis lines exhibited significant Cd tolerance with increased Ca (∼10-fold) accumulation. The proline content and antioxidant enzymes activities were increased while oxidative stress-related molecules such as H2O2 and MDA were reduced in the transgenic lines. In addition, the growth and yield parameters of transgenic lines such as seed germination rate, root length, leaf biomass, leaf area index, rosette diameter, leaf length and width, and silique count, along with various physiological indicators like chlorophyll, carotenoid, and relative water contents were also improved in comparison to the control plants. Further, the transgenic lines exhibited significant salinity and osmotic stress tolerance, as well. Taken together, these results suggested that the TaNCL2-A could mitigate Cd toxicity along with salinity and osmotic stress. This gene may also be utilized for phytoremediation and Cd sequestration in future studies.
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    Jasmonic acid (JA) induced-calcium elevation in Arabidopsis is highly variable due to time of day and conversion to JA-Ile
    (Springer Nature Publishing AG, 2020) Prajapati, Ramgopal; Mittal, Deepika; Meena, Mukesh Kumar; Vadassery, Jyothilakshmi
    Plants have evolved mechanisms to effectively anticipate environmental changes via diurnal rhythmicity (day/night) maintained by the circadian clock. Jasmonic acid biosynthesis and signalling are known to be under the control of the circadian clock. Both JA and its bioactive form jasmonoyl-L-isoleucine (JA-Ile) when externally added can induce a cytosolic Ca2? influx in Arabidopsis thaliana. JA and JA-Ile induced Ca2? is poorly understood and often used interchangeably to study Ca2? regulation of jasmonates. We attempted to understand if they are similar and if diurnal rhythms or time of day regulate them. JA induced Cacyt 2? signature is variable according to time-of-day in Arabidopsis. JA is sensed in two ways according to the time-of-day (a) directly sensed as JA and induces Cacyt 2? elevation (b) JA gets converted into the JA-Ile by JAR1 and is sensed as JA-Ile, which we proved using jar1-1*aequorin. This twin sensing mode is responsible for variability in JA induced Cacyt 2? signature. We further suggest caution when using JA as a stimulant for Cacyt 2? elevation measurements to compare wild-type (Col-0 transformed with pMAQ2; transgenic aequorin) and effect of different mutations. On the other hand bioactive JA-Ile induced Cacyt 2? signature is constant diurnally with maximum amplitude at dawn which coincides with maximum sensitivity of JA-Ile receptor, COI1 and increased VSP2 expression. From the above study we conclude that JA-Ile induced Cacyt 2? elevation is a better read-out than the highly variable JA-induced Cacyt 2? elevations to study the output pathways.
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    Decoding and relay of calcium signals by CBL-CIPK module in plants
    (Indian National Science Academy, 2019) Meena, Mukesh Kumar; Sardar, Atish; Chattopadhyay, Debasis
    Calcium is an essential macronutrient and a second messenger for signal transduction in plants. Apart from acting as a second messenger, calcium is also required for cytoskeleton, cell division, pollen tube growth and as a co-factor. Cytoplasmic calcium ion ([Ca2+](cyt)) is maintained at a low level, however, is rapidly elevated using storages in organelles on perception of a stimulus. Ca2+-binding proteins that sense the kinetics and magnitude of elevated [Ca2+](cyt) convert the chemical signals to biological signals and define specificity of responses. These proteins are broadly classified into sensor relays and sensor responders. Sensor relay proteins require another interacting protein to transmit the signal; whereas, the sensor responders combine within one protein the relay, amplification and response functions. A significant achievement has been made in the last three decades that identified and characterized various proteins instrumental in decoding Ca2+-signals in plant cells. The latest addition in Ca2+-signaling is Calcineurin B-like proteins (CBLs) and their interacting kinases (CIPKs). It is believed that flexibility of interactions between different CBL and CIPK proteins and their sub-cellular localizations are crucial in sensing and responding to specific signals. In this review, we have laid emphasis on the recent and emerging advancements in understanding of the CBL-CIPK module.
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    New evidences about strictosidine synthase (Str) regulation by salinity, cold stress and nitric oxide in Catharanthus roseus
    (Springer, 2013) Dutta, Ajaswrata; Sen, Jayanti; Deswal, Renu
    Alkaloid production in plants is altered by abiotic stressors, but the mechanism(s) are poorly understood. Present study provides novel evidences about differential regulation of strictosidine synthase (Str), the key gene of terpenoid indole alkaloid (TIA) biosynthetic pathway in response to salinity and low temperature stress in Catharanthus roseus. HPLC analysis of terpene indole alkaloids correlated with differential regulation of Str by low temperature and salinity stress. Administration of exogenous calcium and calcium channel modulator preferentially regulated Str transcript. In addition, administration of kinase and phosphatase inhibitors modulated Str expression. Involvement of nitric oxide (NO) signaling was ascertained by NO donor and nitric oxide synthase (NOS) scavenger treatments. This finding suggests co-ordinated action of calcium, protein kinases, phosphatases and nitric oxide in abiotic stress signaling for TIA biosynthetic pathway in C. roseus.