Publications of NIPGR Scientists

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Author: search.filters.author.Singh, Amar PalSubject: search.filters.subject.Ammonium

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    Differential response of rice genotypes to nitrogen availability is associated with the altered nitrogen metabolism and ionomic balance
    (Elsevier B.V., 2022) Kumari, Priyanka; Devi, Loitongbam Lorinda; Kumar, Amresh; Pandey, Ashutosh; Sinha, Subodh Kumar; Singh, Amar Pal
    Nitrogen (N) uptake and its assimilation are crucial steps for plant growth and productivity. Plant's N balance largely depends on nitrate (NO3-) and ammonium (NH4+) forms present in the rhizosphere. Due to the fluctuating and heterogeneous availability of these N forms in the soils, plants encounter low to N deficiency. In contrast to low nitrogen, high N in the form of ammonium (NH4+) severely hampers plant development and causes NH4+ toxicity. In this study, we assessed eleven rice genotypes under sufficient (SN) and low N (LN) conditions. From the analysis, we identified a rice genotype, PB1, which is hypersensitive to SN and showed reduced root and shoot growth. In contrast to the SN condition, PB1 showed improved growth performance under the LN condition. Our data show that compromised growth of PB1 under SN condition is associated with increased activity of N responsive genes such as OsAMT1.1, OsAMT2.3, OsAMT3.1 and OsAMT3.2, OsNRT1.1A and OsNRT1.1B. Strikingly, LN treatment improved the root and shoot biomass with a concomitant increase in levels of NO3- and NH4+ transporter genes along with an increase in shoot: root NO3- ratio. Additionally, we show that increased levels of N in PB1 under SN condition are associated with the enhanced activity of the GS-GOGAT pathway. Further, our ionomic analysis highlighted the role of N-defined Fe accumulation which is partially associated with the N toxicity. Taken together, our study led to identifying a rice genotype (Oryza sativa L.) which is associated with enhanced N levels and assimilation and could be used for raising N use efficient rice varieties using breeding approaches.
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    Review: Emerging roles of brassinosteroid in nutrient foraging
    (Elsevier B.V., 2020) Pandey, Anshika; Devi, Loitongbam Lorinda; Singh, Amar Pal
    Brassinosteroids (BRs) are well-characterized growth hormones that are critical for plant growth, development, and productivity. Genetic and molecular studies have revealed the key components of BR biosynthesis and signaling pathways. The membrane-localized BR signaling receptor, BRASSINOSTEROID INSENSITIVE1 (BRI1) binds directly to its ligand and initiates series of signaling events that led to the activation of BR transcriptional regulators, BRASSINAZOLE RESISTANT1 (BZR1) and BRI1-ETHYL METHANESULFONATE-SUPPRESSOR1 (BES1/BZR2) to regulate the cellular processes. Insights from Arabidopsis research revealed tissue and cell typespecific roles of BR in controlling cell elongation and maintenance of stem cell niche in roots. More recently, BRs have gained much attention in regulating the root growth during nutrient deficiency such as nitrogen, phosphorus, and boron. Differential distribution of nutrients in the rhizosphere alters BR hormone levels and signaling to reprogram spatial distribution of root system architecture (RSA) such as a change in primary root growth, lateral root numbers, length, and angle, root hair formation and elongation. These morpho-physiological changes in RSA are also known as an adaptive root trait or foraging response of the plant. In this review, we highlight the role of BRs in regulating RSA to increase root foraging response during fluctuating nutrient availability.