Browsing by Author "Malakar, Paheli"

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Adaptation of plants to salt stress: the role of the ion transporters
(Springer Nature Publishing AG, 2021) Malakar, Paheli; Chattopadhyay, Debasis
Adaptation to high salinity is achieved by cellular ion homeostasis which involves regulation of toxic sodium ion (Na+) and Chloride ion (Cl−) uptake, preventing the transport of these ions to the aerial parts of the plants and vacuolar sequestration of these toxic ions. Ion transporters have long been known to play roles in maintaining ion homeostasis. Na+ enters the cell through various voltage dependent selective and non-selective ion channels. High Na+ concentration in the plasma membrane is balanced either by uptake of potassium ion (K+) by various potassium importing channels, by salt exclusion mechanism or by sequestration of Na+ in the vacuoles. Therefore, the role of high-affinity potassium transporter, the salt overly sensitive pathway, the most well-defined Na+ exclusion pathway that exports Na+ from cell into xylem and tonoplast localized cation transporters that compartmentalizes Na+ in vacuoles need to be studied in detail and applied to make the plant adaptable to saline soil. Knowledge on the regulation of expression of these transporters by the hormones, microRNAs and other non-coding RNAs can be utilized to manipulate the ion transport. Here, we reviewed paradigm of the ion transporters in salt stress signalling pathways from the recent and past studies aiding transformation of basic knowledge into biotechnological applications to generate engineered salt stress tolerant crops.
Development of an Agrobacterium-delivered codon-optimized CRISPR/Cas9 system for chickpea genome editing
(Springer Nature Publishing AG, 2023) Gupta, Santosh Kumar; Vishwakarma, Niraj Kumar; Malakar, Paheli; Vanspati, Poonam; Sharma, Nilesh Kumar; Chattopadhyay, Debasis
Chickpea is considered recalcitrant to in vitro tissue culture amongst all edible legumes. The clustered, regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9)–based genome editing in chickpea can remove the bottleneck of limited genetic variation in this cash crop, which is rich in nutrients and protein. However, generating stable mutant lines using CRISPR/Cas9 requires efficient and highly reproducible transformation protocols. As an attempt to solve this problem, we developed a modified and optimized protocol for chickpea transformation. This study transformed the single cotyledon half-embryo explants using CaMV35S promoter to drive two marker genes (β-glucuronidase gene; GUS and green fluorescent protein; GFP) through binary vectors pBI101.2 and modified pGWB2, respectively. These vectors were delivered in the explants through three different strains of Agrobacterium tumefaciens, viz., GV3101, EHA105, and LBA4404. We found better efficiency with the strain GV3101 (17.56%) compared with two other strains, i.e., 8.54 and 5.43%, respectively. We recorded better regeneration frequencies in plant tissue culture for the constructs GUS and GFP, i.e., 20.54% and 18.09%, respectively. The GV3101 was further used for the transformation of the genome editing construct. For the development of genome-edited plants, we used this modified protocol. We also used a modified binary vector pPZP200 by introducing a CaMV35S-driven chickpea codon-optimized SpCas9 gene. The promoter of the Medicago truncatula U6.1 snRNA gene was used to drive the guide RNA cassettes. This cassette targeted and edited the chickpea phytoene desaturase (CaPDS) gene. A single gRNA was found sufficient to achieve high efficiency (42%) editing with the generation of PDS mutants with albino phenotypes. A simple, rapid, highly reproducible, stable transformation and CRISPR/Cas9-based genome editing system for chickpea was established. This study aimed to demonstrate this system’s applicability by performing a gene knockout of the chickpea PDS gene using an improved chickpea transformation protocol for the first time.
Role of plant neurotransmitters in salt stress: A critical review
(Elsevier B.V., 2024) Malakar, Paheli; Gupta, Santosh K.; Chattopadhyay, Debasis
Neurotransmitters are naturally found in many plants, but the molecular processes that govern their actions still need to be better understood. Acetylcholine, γ-Aminobutyric acid, histamine, melatonin, serotonin, and glutamate are the most common neurotransmitters in animals, and they all play a part in the development and information processing. It is worth noting that all these chemicals have been found in plants. Although much emphasis has been placed on understanding how neurotransmitters regulate mood and behaviour in humans, little is known about how they regulate plant growth and development. In this article, the information was reviewed and updated considering current thinking on neurotransmitter signaling in plants' metabolism, growth, development, salt tolerance, and the associated avenues for underlying research. The goal of this study is to advance neurotransmitter signaling research in plant biology, especially in the area of salt stress physiology.
Root-specific expression of chickpea cytokinin oxidase/dehydrogenase 6 leads to enhanced root growth, drought tolerance and yield without compromising nodulation
(John Wiley & Sons, 2020) Khandal, Hitaishi; Gupta, Santosh Kumar; Dwivedi, Vikas; Mandal, Drishti; Sharma, Nilesh Kumar; Vishwakarma, Niraj Kumar; Pal, Lalita; Choudhary, Megha; Francis, Aleena; Malakar, Paheli; Singh, Nagendra Pratap; Sharma, Kapil; Sinharoy, Senjuti; Singh, Narendra Pratap; Sharma, Rameshwar; Chattopadhyay, Debasis
Cytokinin group of phytohormones regulate root elongation and branching during post‐embryonic development. Cytokinin degrading enzymes cytokinin oxidases/dehydrogenases (CKXs) have been deployed to investigate biological activities of cytokinin and to engineer root growth. We expressed chickpea cytokinin oxidase 6 (CaCKX6) under the control of a chickpea root‐specific promoter of CaWRKY31 in Arabidopsis thaliana and chickpea having determinate and indeterminate growth patterns, respectively, to study the effect of cytokinin depletion on root growth and drought tolerance. Root‐specific expression of CaCKX6 led to a significant increase in lateral root number and root biomass in Arabidopsis and chickpea without any penalty to vegetative and reproductive growth of shoot. Transgenic chickpea lines showed increased CKX activity in root. Soil‐grown advanced chickpea transgenic lines exhibited higher root‐to‐shoot biomass ratio and enhanced long‐term drought tolerance. These chickpea lines were not compromised in root nodulation and nitrogen fixation. The seed yield in some lines was up to 25% higher with no penalty in protein content. Transgenic chickpea seeds possessed higher levels of zinc, iron, potassium and copper. Our results demonstrated the potential of cytokinin level manipulation in increasing lateral root number and root biomass for agronomic trait improvement in an edible legume crop with indeterminate growth habit.