Institutional Publications

Permanent URI for this collectionhttps://ndkr-library.nipgr.ac.in/handle/123456789/11

Browse

Start date: 2020Subject: search.filters.subject.Nitrogen

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    A cytokinin-auxin antagonistic module participates in nitrogen-triggered tiller outgrowth in rice
    (Oxford University Press, 2026) Chatterjee, Sourav; Dwivedi, Aditi; Sarkar, Ananda K; Ranjan, Aashish
    Tillering is a key trait that shapes rice (Oryza sativa L.) shoot architecture and directly influences yield. While tiller bud formation is largely genetically determined, bud outgrowth into functional tillers is highly responsive to environmental cues. However, integration of environmental signals with genetic regulators to determine tiller bud fate remains poorly understood. Here, we investigated the effects of nitrogen on early stages of tiller bud outgrowth. Comprehensive phenotyping and temporal transcriptomic analyses demonstrated that both nitrate and ammonium promote bud outgrowth and elicit overlapping transcriptional responses, with nitrate acting more slowly. Gene regulatory network analysis identified phytohormone signaling as a key interface for nitrogen- triggered tiller outgrowth. Pharmacological and molecular experiments demonstrated the involvement of cytokinin–auxin antagonism in nitrogen-mediated tillering. Cytokinin promoted bud activation by repressing the critical bud dormancy regulators rice TEOSINTE BRANCHED 1 (OsTB1) and a homolog of PIN-FORMED 1 (OsPIN1a) through the Cytokinin Response Factors OsERF53/54. In contrast, auxin maintained dormancy by inducing OsTB1 and OsPIN1a expression through Auxin Response Factors OsARF11/16. Consistently, OsTB1 overexpression lines showed reduced responsiveness to nitrogen and hormone treatments, placing OsTB1 downstream of these convergent inputs. Sequence and gene expression differences in OsERF53/54, along with phenotypic variations across contrasting rice accessions, further substantiated the crucial roles of OsERF53/54 in nitrogen-mediated tillering. Together, we identify a key regulatory role of the cytokinin-auxin antagonistic module for integrating nitrogen signals to determine tiller bud fate. Adequate nitrogen promotes cytokinin signaling while attenuating auxin signaling and transport in tiller buds, thereby releasing dormancy and initiating bud outgrowth.
  • Thumbnail Image
    Item
    An overview of important enzymes involved in nitrogen assimilation of plants
    (Springer Nature Publishing AG, 2020) Kishorekumar, Reddy; Bulle, Mallesham; Wany, Aakanksha; Gupta, Kapuganti Jagadis
    Nitrogen (N) is a macro-nutrient that is essential for growth development and resistance against biotic and abiotic stresses of plants. Nitrogen is a constituent of amino acids, proteins, nucleic acids, chlorophyll, and various primary and secondary metabolites. The atmosphere contains huge amounts of nitrogen but it cannot be taken up directly by plants. Plants can take up nitrogen in the form of nitrate, ammonium, urea, nitrite, or a combination of all these forms. In addition, in various leguminous rhizobia, bacteria can convert atmospheric nitrogen to ammonia and supply it to the plants. The form of nitrogen nutrition is also important in plant growth and resistance against pathogens. Nitrogen content has an important function in crop yield. Nitrogen deficiency can cause reduced root growth, change in root architecture, reduced plant biomass, and reduced photosynthesis. Hence, understanding the function and regulation of N metabolism is important. Several enzymes and intermediates are involved in nitrogen assimilation. Here we provide an overview of the important enzymes such as nitrate reductase, nitrite reductase, glutamine synthase, GOGAT, glutamate dehydrogenase, and alanine aminotransferase that are involved in nitrogen metabolism.
  • Thumbnail Image
    Item
    Expression analysis of important genes involved in nitrogen metabolism under hypoxia
    (Springer Nature Publishing AG, 2020) Bulle, Mallesham; Kishorekumar, Reddy; Wany, Aakanksha; Gupta, Kapuganti Jagadis
    Hypoxia or anoxia condition can occurs during flooding or waterlogging and can cause intense damage to the plants. Since oxygen is important for active operation of electron transport chain in mitochondria to generate energy production (ATP) any drop in oxygen can cause an energy crisis during flooding/waterlogging. To cope with this energy crisis plants have developed various anatomical, physiological, and biochemical adaptations. Perception of signals and induction of genes are required for initiation of these adaptive responses. Various genes involved in nitrogen, carbon, and fermentative metabolism play a role in hypoxic tolerance. Regulation of genes involved in nitrogen metabolism also plays a role under hypoxia. Hence in this present chapter we describe the expression of nitrate reductase-1 (NIA1), nitrate reductase-2 (NIA2), and glutamine synthetase-1 (GLN-1) during hypoxia in Arabidopsis.