Browsing by Author "Gupta, Shreya"

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The interplay of auxin and brassinosteroid signaling tunes root growth under low and different nitrogen forms
(Oxford University Press, 2022) Devi, Loitongbam Lorinda; Pandey, Anshika; Gupta, Shreya; Singh, Amar Pal
The coordinated signaling activity of auxin and brassinosteroids (BRs) is critical for optimal plant growth and development. Nutrient-derived signals regulate root growth by modulating the levels and spatial distribution of growth hormones to optimize nutrient uptake and assimilation. However, the effect of the interaction of these two hormones and their signaling on root plasticity during low and differential availability of nitrogen (N) forms (NH4+/NO3-) remains elusive. We demonstrate that root elongation under low nitrogen (LN) is an outcome of the interdependent activity of auxin and BR signaling pathways in Arabidopsis (Arabidopsis thaliana). LN promotes root elongation by increasing BR-induced auxin transport activity in the roots. Increased nuclear auxin signaling and its transport efficiency have a distinct impact on root elongation under LN conditions. High auxin levels reversibly inhibit BR signaling via BRI1 KINASE INHIBITOR1 (BKI1). Using the tissue-specific approach, we show that BR signaling from root vasculature (stele) tissues is sufficient to promote cell elongation and, hence, root growth under LN condition. Further, we show that N form-defined root growth attenuation or enhancement depends on the fine balance of BR and auxin signaling activity. NH4+ as a sole N source represses BR signaling and response, which in turn inhibits auxin response and transport, whereas NO3- promotes root elongation in a BR signaling–dependent manner. In this study, we demonstrate the interplay of auxin and BR-derived signals, which are critical for root growth in a heterogeneous N environment and appear essential for root N foraging response and adaptation.
Jasmonate signaling modulates root growth by suppressing iron accumulation during ammonium stress
(Oxford University Press, 2024) Pandey, Anshika; Devi, Loitongbam Lorinda; Gupta, Shreya; Prasad, Priti; Agrwal, Kanupriya; Asif, Mehar Hasan; Pandey, Ajay Kumar; Bandyopadhyay, Kaustav; Singh, Amar Pal
Plants adapt to changing environmental conditions by adjusting their growth physiology. Nitrate (NO3-) and ammonium (NH4+) are the major inorganic nitrogen forms for plant uptake. However, high NH4+ inhibits plant growth, and roots undergo striking changes, such as inhibition of cell expansion and division, leading to reduced root elongation. In this work, we show that high NH4+ modulates nitrogen metabolism and root developmental physiology by inhibiting iron (Fe)-dependent Jasmonate (JA) signaling and response in Arabidopsis (Arabidopsis thaliana). Transcriptomic data suggested that NH4+ availability regulates Fe and JA-responsive genes. High NH4+ levels led to enhanced root Fe accumulation, which impaired nitrogen balance and growth by suppressing JA biosynthesis and signaling response. Integrating pharmacological, physiological, and genetic experiments revealed the involvement of NH4+ and Fe-derived responses in regulating root growth and nitrogen metabolism through modulation of the JA pathway during NH4+ stress. The JA signaling transcription factor MYC2 directly bound the promoter of the NITRATE TRANSPORTER 1.1 (NRT1.1) and repressed it to optimize the NH4+/Fe-JA balance for plant adaptation during NH4+ stress. Our findings illustrate the intricate balance between nutrient and hormone-derived signaling pathways that appear essential for optimizing plant growth by adjusting physiological and metabolic responses during NH4+/Fe stress.
Nitric oxide: Interaction with auxins, brassinosteroids, and abscisic acid
(John Wiley & Sons, 2022) Gupta, Shreya; Devi, Loitongbam Lorinda; Singh, Amar Pal
Studies have identified the central role of nitric oxide in stress mitigation through the modulation of physiological and biochemical pathways including germination, photosynthesis regulation, and programmed cell death. Nitric Oxide in Plants: A Molecule with Dual Roles provides a detailed account of the physio-biochemical, molecular, and omic basis of NO-mediated responses in crop plants under different stresses. Summarizing recent work from leading researchers in the field, this up-to-date volume presents the current understanding of the modulation of the endogenous nitric oxide concentration following exogenous treatments and nitric oxide scavengers or inhibitors. The contributors discuss topics such as NO-mediated regulation of growth, photosynthesis, and tolerance mechanisms, the reductive and oxidative pathways of NO synthesis, molecular interventions for enhancing NO synthesis, the role of nitrogen in production of NO, beneficial microbes in NO production under normal and changing environmental conditions, and more.
Plant growth coordination during stress conditions: Role of phytohormones
(Elsevier B.V., 2024) Gupta, Shreya; Devi, Loitongbam Lorinda; Singh, Amar Pal
Plants encounter multiple stresses which are associated with compromised plant growth and yield across the globe. Several studies have been done in the past few years to understand plant acclimatization under numerous stresses like nutrient deficiency, drought, salinity, temperature, and pathogen attack. The shoot and root system architecture in plants seems a promising approach as it is highly sensitive to edaphic and internal signals and plants adapt by modulating them to these stresses. Intrinsic factors such as growth hormones are the key components of the plant whose levels and signaling determine the extent of plant growth and performance. The major phytohormones that are involved in monitoring plant development for optimized plant growth during environmental stresses are auxin, brassinosteroids, cytokinin, abscisic acid, jasmonic acid, gibberellins, and ethylene. In recent years, detailed genetic and biochemical analysis of the signaling and biosynthesis genes and transcription factors of these hormones have been studied from the model plant Arabidopsis to different crops. Genetic studies have shown that these hormones regulate several biological processes of root and shoot growth including cell elongation, division and differentiation, root hair and lateral root formation, and floral and leaf morphology in response to altered environmental conditions. In this chapter, the current understanding of both above- and below-ground plant organs and their developmental plasticity during stress conditions along with the interplay of growth hormones has been summarized and discussed.
Review: Nutrient-nutrient interactions governing underground plant adaptation strategies in a heterogeneous environment
(Elsevier B.V., 2024) Singh, Kratika; Gupta, Shreya; Singh, Amar Pal
Plant growth relies on the mineral nutrients present in the rhizosphere. The distribution of nutrients in soils varies depending on their mobility and capacity to bind with soil particles. Consequently, plants often encounter either low or high levels of nutrients in the rhizosphere. Plant roots are the essential organs that sense changes in soil mineral content, leading to the activation of signaling pathways associated with the adjustment of plant architecture and metabolic responses. During differential availability of minerals in the rhizosphere, plants trigger adaptation strategies such as cellular remobilization of minerals, secretion of organic molecules, and the attenuation or enhancement of root growth to balance nutrient uptake. The interdependency, availability, and uptake of minerals, such as phosphorus (P), iron (Fe), zinc (Zn), potassium (K), nitrogen (N) forms, nitrate (NO3-), and ammonium (NH4+), modulate the root architecture and metabolic functioning of plants. Here, we summarized the interactions of major nutrients (N, P, K, Fe, Zn) in shaping root architecture, physiological responses, genetic components involved, and address the current challenges associated with nutrient-nutrient interactions. Furthermore, we discuss the major gaps and opportunities in the field for developing plants with improved nutrient uptake and use efficiency for sustainable agriculture.