Publications of NIPGR Scientists

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Author: search.filters.author.Pareek, AshwaniSubject: search.filters.subject.phytoglobin

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    Overexpression of phytoglobin1 in rice leads to enhanced nitrogen use efficiency via modulation of nitric oxide
    (John Wiley & Sons, 2025) Samant, Sanjib Bal; Swain, Jagannath; Yadav, Nidhi; Yadav, Reena; Singh, Pooja; Rai, Preeti; Sheri, Vijay; Sreeman, Sheshshayee; Subramanyam, Rajagopal; Pareek, Ashwani; Gupta, Kapuganti Jagadis
    Nitric oxide (NO) is one of the byproducts of nitrogen metabolism. Excess amount of NO is scavenged by phytoglobins. The role of phytoglobin mediated NO homoeostasis in modulation of nitrate transporters was investigated using NO scavenger cPTIO, phytoglobin overexpressing rice and Arabidopsis. Growing plants under low nitrate leads to generation of reduced levels of NO accompanied by elevated expression of high affinity transporters (HATs) such as NRT2.1, NRT2.3 and NRT2.4. Scavenging of NO by cPTIO under optimal nitrate caused enhanced HATs expression. Phytoglobin overexpressing Arabidopsis showed improved growth and enhanced expression of HATs under low nitrogen in comparison to WT. Pretreatment of optimal nitrate grown plants with NO scavenger cPTIO enhanced HATs expression and shifting of these primed plants from optimal to low nitrate leads to further elevation of HATs expression accompanied by enhanced nitrogen uptake and its accumulation with positive effect on growth. Phytoglobin overexpression in rice leads to enhanced HATs expression, improved growth, nitrogen accumulation under low nitrate. Pgb OE lines showed enhanced accumulation of amino acids. Taken together our results suggest an important role of phytoglobins in nitrogen uptake and assimilation.
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    Nitric oxide, energy and redox-dependent responses to hypoxia
    (Oxford University Press, 2024) Samant, Sanjib Bal; Yadav, Nidhi; Swain, Jagannath; Joseph, Josepheena; Kumari, Aprajita; Praveen, Afsana; Sahoo, Ranjan Kumar; Manjunatha, Girigowda; Seth, Chandra Shekar; Singla-Pareek, Sneh Lata; Foyer, Christine H; Pareek, Ashwani; Gupta, Kapuganti Jagadis
    Hypoxia occurs when the oxygen levels fall below the levels required for mitochondria to support respiration. Regulated hypoxia is associated with quiescence, particularly in storage organs (seeds) and stem cell niches. In contrast, environmentally-induced hypoxia poses significant challenges for metabolically-active cells that are adapted to aerobic respiration. The perception of oxygen availability through cysteine oxidases, which function as oxygen-sensing enzymes in plants that control the N-degron pathway, and the regulation of hypoxia-responsive genes and processes is essential to survival. Functioning together with reactive oxygen species (ROS), particularly hydrogen peroxide and reactive nitrogen species (RNS), such as nitric oxide (•NO), nitrogen dioxide (•NO2), S‐nitrosothiols (SNOs), and peroxynitrite (ONOO−), hypoxia signaling pathways trigger anatomical adaptations such as formation of aerenchyma, mobilization of sugar reserves for anaerobic germination, formation of aerial adventitious roots and hyponastic response. NO and hydrogen peroxide (H2O2) participate in local and systemic signaling pathways that facilitate acclimation to changing energetic requirements, controlling glycolytic fermentation, the GABA shunt and amino acid synthesis. NO enhances antioxidant capacity and contributes to the recycling of redox equivalents energy metabolism through the phytoglobin (Pgb)-NO cycle. Here, we summarize current knowledge, highlighting the central role of NO and redox regulation in adaptive responses that prevent hypoxia-induced death in challenging conditions such as flooding.