Browsing by Author "Deepika"

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Dark-induced hormonal regulation of plant growth and development
(Frontiers Media S.A., 2020) Deepika; Ankit; Sagar, Sushma; Singh, Amarjeet
The 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.
Expression dynamics indicate the role of Jasmonic acid biosynthesis pathway in regulating macronutrient (N, P and K+) deficiency tolerance in rice (Oryza sativa L.)
(Springer Nature Publishing AG, 2021) Deepika; Singh, Amarjeet
Key message: Expression pattern indicates that JA biosynthesis pathway via regulating JA levels might control root system architecture to improve nutrient use efciency (NUE) and N, P, K+ defciency tolerance in rice. Abstract: Defciencies of macronutrients (N, P and K+) and consequent excessive use of fertilizers have dramatically reduced soil fertility. It calls for development of nutrient use efcient plants. Plants combat nutrient defciencies by altering their root system architecture (RSA) to enhance the acquisition of nutrients from the soil. Amongst various phytohormones, Jasmonic acid (JA) is known to regulate plant root growth and modulate RSA. Therefore, to understand the role of JA in macronutrient defciency in rice, expression pattern of JA biosynthesis genes was analyzed under N, P and K+ defciencies. Several members belonging to diferent families of JA biosynthesis genes (PLA1, LOX, AOS, AOC, OPR, ACX and JAR1) showed diferential expression exclusively in one nutrient defciency or in multiple nutrient defciencies. Expression analysis during developmental stages showed that several genes expressed signifcantly in vegetative tissues, particularly in root. In addition, JA biosynthesis genes were found to have signifcant expression under the treatment of diferent phytohormones, including Auxin, cytokinin, gibberellic acid (GA), abscisic acid (ABA), JA and abiotic stresses, such as drought, salinity and cold. Analysis of promoters of these genes revealed various cis-regulatory elements associated with hormone response, plant development and abiotic stresses. These fndings suggest that JA biosynthesis pathway by regulating the level of JA might control the RSA thus, it may help rice plant in combating macronutrient defciency.
Genome-wide identification, structure analysis and expression profiling of phospholipases D under hormone and abiotic stress treatment in chickpea (Cicer arietinum)
(Elsevier B.V., 2021) Sagar, Sushma; Deepika; Biswas, Dipul Kumar; Chandrasekar, Ramsankar; Singh, Amarjeet
Phospholipases D (PLDs) are phospholipid hydrolyzing enzymes and crucial components of lipid signaling in plants. PLDs are implicated in stress responses in different plants however, characterization of PLDs in chickpea is missing. Here, we identify 13 PLD genes in the chickpea genome. PLD family could be divided into α, β, δ, ε and ζ isoforms based on sequence and structure. Protein remodeling described that chickpea PLDs are composed of defined arrangements of α-helix, β-sheets and short loops. Phylogenetic analysis suggested evolutionary conservation of chickpea PLD family with dicots. In-planta subcellular localization showed the plasma membrane localization of chickpea PLDs. All PLD promoters had hormone and stress related cis-regulatory elements, which suggested overlapping function of PLDs in hormone and abiotic stress signaling. The qRT-PCR expression analysis revealed that most PLD genes are differentially expressed in multiple abiotic stresses (drought, salt and cold stress). Moreover, several PLD genes had overlapping expression in abiotic stress and ABA and JA treatment. These observations indicate the involvement of PLD gene family in cross-talk of phytohormone and abiotic stress signaling in chickpea. Thus, present study opens new avenues of utilizing PLD related information for understanding hormone-regulated abiotic stress signaling in legume crops.
Regulation of stress responses in plants by calcium dependent protein kinases
(John Wiley & Sons, 2021) Deepika; Mali, Komal Vitthalrao; Kumar, Amit; Singh, Amarjeet
Calcium‐dependent protein kinases (CDPKs) represent the group of major calcium (Ca2+) sensors in plants. CDPKs comprise of peculiar structural features due to which they play a dual role of “Ca2+ sensor and responder” and decode the message from specific Ca2+ signature to phosphorylation events. Onset of most of the stresses results in increase in cytosolic Ca2+ level in plant cell. In depth functional analyses across plant species showed regulation of CDPK transcripts, activity, protein interactions and substrate targeting under biotic and abiotic stresses. Thus, vital role of CDPKs is proposed in transduction of stress triggered Ca2+ signaling to adaptive responses in plants. Genetic manipulations using CDPK genes could be vital in the agricultural biotechnology for imparting tolerance to biotic and abiotic stress, and better productivity. In this chapter, we provide an overview and update of CDPK gene family organization, CDPK domain structure and regulatory mechanism, the role of various CDPKs in abiotic stress, biotic stress signaling and responses in the model and crop plants.