Publications of NIPGR Scientists

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Subject: search.filters.subject.Nitrogen assimilation

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    Brassinosteroids-regulated nitrogen metabolism fine-tunes growth physiology and low nitrogen response in tomato
    (Elsevier B.V., 2023) Yadav, Ritesh Kumar; Analin, Benedict; Panda, Mahesh Kumar; Ranjan, Aashish; Singh, Amar Pal
    Nitrogen (N) is a crucial nutrient for plants and its limited availability in the soils significantly affects plant growth and development. To adapt under low N condition, plants undergo various changes such as root system reprogramming to explore deeper soil horizons and metabolic activity adjustment. These N dependent responses and the genetic factors governing them are poorly known in crop plants. In this study, we investigated the effect of BRs on N metabolism in tomato. BRs application improved N assimilation and metabolic responses. By using the transgenic approach, we demonstrated the essential role of tomato Brassinazole resistant (BES1/BZR1) homolog 4 (BEH4) protein in regulating N metabolic response, growth physiology, and fruit quality. Overexpression of BEH4 promoted deeper root system architecture and improved physiological performance by adjusting N metabolic activity and photosynthetic efficiency in low N-grown plants. The BEH4 transgenic lines exhibited increased expression of genes involved in N uptake and assimilation which are associated with the improved N content and assimilation (root and shoot). Altogether, data suggested an essential role of BRs in plant adaptation to altered N regimes and appears potential target for genetic manipulation to improve nitrogen use efficiency (NUE) and nutritional quality in crops.
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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.