Institutional Publications

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Author: search.filters.author.Sinha, Alok KrishnaSubject: search.filters.subject.Arsenic

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    Transcriptomic and OsWAK24-MPK3 crosstalk reveal resistance mechanism of primed rice seedlings against Arsenic-Iron
    (Oxford University Press, 2026) Bhatia, Priyanka; Mittal, Lavanya; Pandey, Shubhangi; Khatoon, Narjis Saba; Sinha, Alok Krishna; Gupta, Meetu
    Priming, elucidated as "memory," refers to the preconditioning of plant's stress responses to enhance resilience toward future stressors, including arsenic (As) contamination. This adaptive preparedness becomes further complex under As-Fe(iron) interplay, which remains scarcely delineated within priming background. Here, we employed Illumina sequencing to acquire global transcriptome alterations and heterologous interaction approach to chart the molecular reprogramming associated with As and As-Fe-dynamics in primed rice. The transcriptome revealed 3005 and 3650 genes to be differentially regulated in As and As-Fe-exposed primed seedlings. Comprehensive elucidation of expression profiling revealed that key genes were involved in transportation (OsNramp, OsFCR, OsNAS), signalling (OsWRKY, OsMYB, OsAP2, OsZF-TF), and defence (OsHSP, OsPRX, OsCyt P450). The antioxidant (OsGST, OsAPX) expression correlated well with their respective physiological enzyme activity. The entire WAK module, transducing extracellular signals to intercellular pathways, was differentially regulated under As and As-Fe influence. Notably, OsWAK24 revealed higher expression under As-Fe, reflecting its association with seedlings' tolerance behaviour. The computational protein network and docking unfolded OsMPK3 as an interactor of OsWAK24. The split-ubiquitin-based yeast-hybrid assay and immunoblot revealed OsWAK24-OsMPK3 association, suggesting OsMPK3 phosphorylates OsWAK24 at serine residue. Overall, the results decoded the seedling's resilience mechanism and aid in developing rice varieties with desired traits.
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    Unraveling the molecular aspects of iron-mediated OsWRKY76 signaling under arsenic stress in rice
    (Elsevier B.V., 2023) Mirza, Zainab; Jonwal, Sarvesh; Saini, Himanshu; Sinha, Alok Krishna; Gupta, Meetu
    Arsenic (As) is a significant environmental element that restricts the growth and production of rice plants. Although the role of iron (Fe) to sequester As in rice is widely known, the molecular mechanism regarding As–Fe interaction remains opaque. Here, we show the differential response of two rice varieties (Ratna and Lalat) in terms of their morphological and biochemical changes in the presence of As and Fe. These results together with in-silico screening, gene expression analysis, and protein-protein interaction studies suggest the role of OsWRKY76 in Fe-mediated As stress alleviation. When OsWRKY76 is activated by MAPK signaling, it inhibits the gene expression of Fe transporters OsIRT1 and OsYSL2, which reduces the amount of Fe accumulated. However, MAPK signaling and OsWRKY76 remain down-regulated during Fe supplementation with As, which subsequently encourages the up-regulation of OsIRT1 and OsYSL2. This results in greater Fe content and decreased As accumulation and toxicity. The lower H2O2 and SOD, CAT, and APX activities were likewise seen under the As + Fe condition. Overall, results revealed the molecular aspects of Fe-mediated control of OsWRKY76 signaling and showed that Ratna is a more As tolerant variety than Lalat. Lalat, however, performs better in As stress due to the presence of Fe.
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    Arsenic stress activates MAP kinase in rice roots and leaves
    (Elsevier, 2011) Rao, Kudupudi Prabhakara; Vani, Gubbala; Kumar, Kundan; Wankhede, Dhammaprakash Pandhari; Misra, Mohit; Gupta, Meetu; Sinha, Alok Krishna
    The toxic metalloid arsenite has become a potential threat to rice growing regions leading to serious contamination in food chain. In the present study effect of different physiological concentration of arsenite that is toxic and triggers the molecular events were evaluated in rice seedlings. Along with severe effect on the growth of rice seedling, production of reactive oxygen species (ROS) and nitric oxide (NO) in arsenite treated rice roots was also observed. Activation of a 42kDa mitogen activated protein kinase (MAPK/MPK) by arsenite was observed in rice leaves and 42 and 44kDa in roots in dose dependent manner. The activated MAPK could be immunoprecipitated with anti-phospho-tyrosine antibody, 4G10. The kinetic of MAPK activation by arsenite was found to be dose dependent. Transcript analysis of MAPK family and immunokinase assay in arsenite treated rice seedling revealed significant level of induction in OsMPK3 transcripts in leaves and OsMPK3, OsMPK4 transcripts in roots. Among MAPK kinase (MKKs) gene family, OsMKK4 transcripts were found to be induced in arsenite treated rice leaves and roots. In-silico homology modeling and docking analysis supported OsMPK3-OsMKK4 interaction. The data indicates that arsenite stress is transduced through MAPK signaling cascade in rice.