Publications of NIPGR Scientists
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Item OsMED14_2, a tail module subunit of mediator complex, controls rice development and involves jasmonic acid(Elsevier B.V., 2024) Prusty, Ankita; Mehra, Poonam; Sharma, Shivam; Malik, Naveen; Agarwal, Pinky; Parida, Swarup K.; Kapoor, Sanjay; Tyagi, Akhilesh K.The Mediator complex is essential for eukaryotic transcription, yet its role and the function of its individual subunits in plants, especially in rice, remain poorly understood. Here, we investigate the function of OsMED14_2, a subunit of the Mediator tail module, in rice development. Overexpression and knockout of OsMED14_2 resulted in notable changes in panicle morphology and grain size. Microscopic analysis revealed impact of overexpression on pollen maturation, reflected by reduced viability, irregular shapes, and aberrant intine development. OsMED14_2 was found to interact with proteins involved in pollen development, namely, OsMADS62, OsMADS63 and OsMADS68, and its overexpression negatively affected the expression of OsMADS68 and the expression of other genes involved in intine development, including OsCAP1, OsGCD1, OsRIP1, and OsCPK29. Additionally, we found that OsMED14_2 overexpression influences jasmonic acid (JA) homeostasis, affecting bioactive JA levels, and expression of OsJAZ genes. Our data suggest OsMED14_2 may act as a regulator of JA-responsive genes through its interactions with OsHDAC6 and OsJAZ repressors. These findings contribute to better understanding of the Mediator complex's role in plant traits regulation.Item Genomic and transcriptomic approaches to developing abiotic stress-resilient crops(MDPI AG, 2023) Kamali, Saravanappriyan; Singh, AmarjeetIn the realm of agriculture, a pressing concern remains the abiotic stresses, such as temperature fluctuation, drought, soil salinity, and heavy metal contamination. These adverse growth conditions hamper crop yields and global food security. In this review, we present a comprehensive examination of the recent advancements in utilizing genomics and transcriptomics, tools to enhance crop resilience against these stress factors. Genomics aids in the identification of genes responsive to stress, unravels regulatory networks, and pinpoints genetic variations linked to stress tolerance. Concurrently, transcriptomics sheds light on the intricate dynamics of gene expression during stress conditions, unearthing novel stress-responsive genes and signaling pathways. This wealth of knowledge shapes the development of stress-tolerant crop varieties, achieved through conventional breeding programs and state-of-the-art genetic engineering and gene editing techniques like CRISPR-Cas9. Moreover, the integration of diverse omics data and functional genomics tools empowers precise manipulation of crop genomes to fortify their stress resilience. In summary, the integration of genomics and transcriptomics holds substantial promise in elucidating the molecular mechanisms behind crop stress tolerance, offering a path towards sustainable agriculture and safeguarding food security amidst shifting environmental challenges.Item Paradigm and framework of WUS-CLV feedback loop in stem cell niche for SAM maintenance and cell identity transition(MDPI AG, 2022) Agarwal, Yamini; Shukla, Bhavya; Manivannan, Abinaya; Soundararajan, PrabhakaranShoot apical meristem (SAM) consists of stem cells that act as a reservoir for the aerial growth. It plays an important role in the differential architectural development in plants. SAM actively performs parallel functions by maintaining the pluripotent of stem cells and continuous organogenesis throughout the plant’s life cycle. Molecular mechanisms regulating the signaling networks of this dual function of the SAM have been progressively understood. In the SAM, the feedback loop of WUSCHEL (WUS)-CLAVATA (CLV) has been found to be the key regulator in stabilizing stem cell proliferation and differentiation. In general, WUS migrates into central zone (CZ) from organizing center (OC) and activates the expression of CLV3 by binding to the promoter elements. CLV3 acts as a ligand to interact with the CLV1, leucine rich repeats (LRR) receptor-like kinase (RLK) and LRR receptor-like protein CLV2, and protein kinase coryne (CRN) (CLV2/CRN) to restrict WUS transcription to the OC. Evolution of CLV3 is one of the main factors contributing to the transformation of two dimensional (2D) to 3D plants. WUS-CLV loop is involved in several pathways and networks that integrate on meristem maintenance and cell identity transition. WUSCLV maintains stem cells with simultaneous differentiation signals by the spatial-temporal signaling of the phytohormones. WUS-CLV loop has an interaction with reactive oxygen species (ROS), an important signaling molecules regulating cell proliferation and developmental transition. WUS also forms feedback loop with AGAMOUS (AG) for differentiation, proliferation, and termination of floral meristem. These loops might also involve in interaction with vernalization and its regulatory factors that oversees the precise timing of flowering after exposure to cold temperatures. In this review, we highlight the evolutionary and developmental importance of the WUS-CLV feedback loop on SAM maintenance and cell identity transition for inflorescence and floral meristem development.Item Jasmonates as emerging regulators of plants response to variable nutrient environment(Taylor & Francis Group, 2022) Kamali, Saravanappriyan; Singh, AmarjeetJasmonates (JAs) are known for their roles in plant defense and growth regulation. In recent years their roles in nutrient uptake and homeostasis have been explored. Regulation of nutrients uptake is crucial to maintain their optimum level in normal and deficient conditions. Under the deficiency of different nutrients, plants show unique responses like altered root growth, remodeling of root system architecture (RSA), induction of nutrient uptake-related genes, activation of nutrient transporters, and nutrient reallocation. JAs have been shown to regulate these responses in the variable availability of macro-and micronutrients. Emerging evidences revealed that in response to deficiency of macronutrients, such as nitrogen (N), phosphorous (P), and potassium (K+), JA biosynthesis pathway is activated. JA signaling pathway has been implicated in regulating nutrient deficiency-related transcription factors, transporters, and various facets of RSA for optimum plant development. In addition, JA pathway cross-talks with other phytohormones like auxin and ethylene for improving plant growth and adaptive response under nutrient deficiencies. In this review, emerging evidences and the latest developments on involvements of JAs in macro- and micronutrient uptakes, homeostasis, deficiency response, and plant development are discussed.Item Molecular characterization reveals the involvement of calcium dependent protein kinases in abiotic stress signaling and development in chickpea (Cicer arietinum)(Frontiers Media S.A., 2022) Deepika, Deepika; Poddar, Nikita; Kumar, Shailesh; Singh, AmarjeetCalcium-dependent protein kinases (CDPKs) are a major group of calcium (Ca2+) sensors in plants. CDPKs play a dual function of "Ca2+ sensor and responder." These sensors decode the "Ca2+ signatures" generated in response to adverse growth conditions such as drought, salinity, and cold and developmental processes. However, knowledge of the CDPK family in the legume crop chickpea is missing. Here, we have identified a total of 22 CDPK genes in the chickpea genome. The phylogenetic analysis of the chickpea CDPK family with other plants revealed their evolutionary conservation. Protein homology modeling described the three-dimensional structure of chickpea CDPKs. Defined arrangements of α-helix, β-strands, and transmembrane-helix represent important structures like kinase domain, inhibitory junction domain, N and C-lobes of EF-hand motifs. Subcellular localization analysis revealed that CaCDPK proteins are localized mainly at the cytoplasm and in the nucleus. Most of the CaCDPK promoters had abiotic stress and development-related cis-regulatory elements, suggesting the functional role of CaCDPKs in abiotic stress and development-related signaling. RNA sequencing (RNA-seq) expression analysis indicated the role of the CaCDPK family in various developmental stages, including vegetative, reproductive development, senescence stages, and during seed stages of early embryogenesis, late embryogenesis, mid and late seed maturity. The real-time quantitative PCR (qRT-PCR) analysis revealed that several CaCDPK genes are specifically as well as commonly induced by drought, salt, and Abscisic acid (ABA). Overall, these findings indicate that the CDPK family is probably involved in abiotic stress responses and development in chickpeas. This study provides crucial information on the CDPK family that will be utilized in generating abiotic stress-tolerant and high-yielding chickpea varieties.Item Dark-induced hormonal regulation of plant growth and development(Frontiers Media S.A., 2020) Deepika; Ankit; Sagar, Sushma; Singh, AmarjeetThe sessile nature of plants has made them extremely sensitive and flexible towards the constant flux of the surrounding environment, particularly light and dark. The light is perceived as a signal by specific receptors which further transduce the information through the signaling intermediates and effector proteins to modulate gene expression. Signal transduction induces changes in hormone levels that alters developmental, physiological and morphological processes. Importance of light for plants growth is well recognized, but a holistic understanding of key molecular and physiological changes governing plants development under dark is awaited. Here, we describe how darkness acts as a signal causing alteration in hormone levels and subsequent modulation of the gene regulatory network throughout plant life. The emphasis of this review is on dark mediated changes in plant hormones, regulation of signaling complex COP/DET/FUS and the transcription factors PIFs which affects developmental events such as apical hook development, elongated hypocotyls, photoperiodic flowering, shortened roots, and plastid development. Furthermore, the role of darkness in shade avoidance and senescence is discussed.Item Mediator subunit OsMED14_1 plays an important role in rice development(John Wiley & Sons, 2020) Malik, Naveen; Ranjan, Rajeev; Parida, Swarup K.; Agarwal, Pinky; Tyagi, Akhilesh K.Mediator, a multi‐subunit coactivator complex, regulates transcription in eukaryotes and is involved in diverse processes in Arabidopsis through its different subunits. Here, we have explored developmental aspects of one of the rice Mediator subunit gene OsMED14_1. We analyzed its expression pattern through RNA in‐situ hybridization and pOsMED14_1:GUS transgenics which showed its expression in roots, leaves, anthers and seeds prominently at younger stages, indicating possible involvement of this subunit in multiple aspects of rice development. To understand developmental roles of OsMED14_1 in rice, we generated and studied RNAi based knockdown rice plants which showed multiple effects including less height, narrower leaves and culms with reduced vasculature, lesser lateral root branching, defective microspore development, reduced panicle branching and seed set, and smaller seeds. Histological analyses showed that slender organs were caused by reduction in both cell number and cell size in OsMED14_1 knockdown plants. Flow cytometric analyses and expression analyses of cell‐cycle related genes revealed that defective cell‐cycle progression led to these defects. Expression analyses of auxin related genes and IAA immuno‐localization study indicated altered auxin level in these knockdown plants. Reduction of lateral root branching in knockdown plants was corrected by exogenous IAA supplement. OsMED14_1 physically interacts with transcription factors YABBY5, TDR and MADS29, possibly regulating auxin homeostasis and ultimately leading to lateral organ/leaf, microspore and seed development.Item May the fittest protein evolve: favoring the plant-specific origin and expansion of NAC transcription factors(John Wiley & Sons, 2018) Mathew, Iny Elizebeth; Agarwal, PinkyPlant‐specific NAC transcription factors (TFs) evolve during the transition from aquatic to terrestrial plant life and are amplified to become one of the biggest TF families. This is because they regulate genes involved in water conductance and cell support. They also control flower and fruit formation. The review presented here focuses on various properties, regulatory intricacies, and developmental roles of NAC family members. Processes controlled by NACs depend majorly on their transcriptional properties. NACs can function as both activators and/or repressors. Additionally, their homo/hetero dimerization abilities can also affect DNA binding and activation properties. The active protein levels are dependent on the regulatory cascades. Because NACs regulate both development and stress responses in plants, in‐depth knowledge about them has the potential to help guide future crop improvement studies.Item Calcium dependent protein kinase, a versatile player in plant stress management and development(Taylor & Francis Group, 2018) Singh, Amarjeet; Sagar, Sushma; Biswas, Dipul KumarCalcium-dependent protein kinases (CDPKs) form the major and unique group of calcium (Ca2+) sensors in plants. Attributed to their peculiar structural features, CDPKs play a dual role of “Ca2+ sensor and responder” and translate the message from specific Ca2+ signature to phosphorylation events. Most of the stress and developmental triggers instigate an increase in Ca2+ level and consequently Ca2+ signaling in plants. Expression and functional analyses across plant species have revealed differential regulation of CDPK transcripts, activity, protein interactions and substrate targeting under different cues, including biotic and abiotic stresses and plant development. Thus, vital roles of CDPKs are proposed in perpetuating stress and development triggered Ca2+ signaling to adaptive responses in plants. Genetic engineering using CDPK genes could be utilitarian in the agricultural biotechnology for imparting higher degree of biotic and abiotic stress tolerance and better productivity. Here, we discuss the recent advancements and update of CDPK gene family organization, domain structure and regulatory mechanism, the role of CDPKs in abiotic stress, biotic stress, development signaling and responses in the model and crop plants.Item Importance of mediator complex in the regulation and integration of diverse signaling pathways in plants(Frontiers Media S.A., 2015) Samanta, Subhasis; Thakur, Jitendra K.Basic transcriptional machinery in eukaryotes is assisted by a number of cofactors, which either increase or decrease the rate of transcription. Mediator complex is one such cofactor, and recently has drawn a lot of interest because of its integrative power to converge different signaling pathways before channeling the transcription instructions to the RNA polymerase II machinery. Like yeast and metazoans, plants do possess the Mediator complex across the kingdom, and its isolation and subunit analyses have been reported from the model plant, Arabidopsis. Genetic, and molecular analyses have unraveled important regulatory roles of Mediator subunits at every stage of plant life cycle starting from flowering to embryo and organ development, to even size determination. It also contributes immensely to the survival of plants against different environmental vagaries by the timely activation of its resistance mechanisms. Here, we have provided an overview of plant Mediator complex starting from its discovery to regulation of stoichiometry of its subunits. We have also reviewed involvement of different Mediator subunits in different processes and pathways including defense response pathways evoked by diverse biotic cues. Wherever possible, attempts have been made to provide mechanistic insight of Mediator's involvement in these processes.