Browsing by Author "Choudhary, Shruti"

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    Adaptability of Rhododendrons in high altitude habitats
    (Northeast Forestry University, 2020-01-03T00:00:00) Choudhary, Shruti; Thakur, Sapna; Majeed, Aasim; Bhardwaj, Pankaj
    Tree species dominate many ecosystems throughout the world and their response to climate, in light of global warming, is a matter of primary concern. This review describes past and ongoing research in Rhododendron, an ecologically important and well-adapted genus of more than 1000 species, occupying diverse habitats. Research to date indicates survival ability and mechanisms, with an emphasis on cold tolerance. The capability of long-distance gene flow in these species increases their genetic variability which in turn enhances their adaptability to newer niches as well as to environmental gradients (mainly temperature). Attempts to explain the molecular basis of morphological and behavioural changes in Rhododendron against cold-induced damage has been made. Gradual advances in �omics� have led to an enriched genomic resource dissecting the role and interaction of multiple molecular factors participating in cold adaptability. However, fewer genetic studies are available on species with an inherent or a default cold-tolerance ability. Considering this fact, understanding specific features of an adapted species can provide insights on overriding the effects of desiccation and determining phase transitions in other plants as well. We propose to integrate ecological and evolutionary studies with functional genomics to improve predictions of tree responses to their environment. � 2020, Northeast Forestry University.
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    Adaptability of Rhododendrons in high altitude habitats
    (Northeast Forestry University, 2020-01-03T00:00:00) Choudhary, Shruti; Thakur, Sapna; Majeed, Aasim; Bhardwaj, Pankaj
    Tree species dominate many ecosystems throughout the world and their response to climate, in light of global warming, is a matter of primary concern. This review describes past and ongoing research in Rhododendron, an ecologically important and well-adapted genus of more than 1000 species, occupying diverse habitats. Research to date indicates survival ability and mechanisms, with an emphasis on cold tolerance. The capability of long-distance gene flow in these species increases their genetic variability which in turn enhances their adaptability to newer niches as well as to environmental gradients (mainly temperature). Attempts to explain the molecular basis of morphological and behavioural changes in Rhododendron against cold-induced damage has been made. Gradual advances in �omics� have led to an enriched genomic resource dissecting the role and interaction of multiple molecular factors participating in cold adaptability. However, fewer genetic studies are available on species with an inherent or a default cold-tolerance ability. Considering this fact, understanding specific features of an adapted species can provide insights on overriding the effects of desiccation and determining phase transitions in other plants as well. We propose to integrate ecological and evolutionary studies with functional genomics to improve predictions of tree responses to their environment. � 2020, Northeast Forestry University.
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    Comparative transcriptome profiling reveals the reprogramming of gene networks under arsenic stress in Indian mustard.
    (Canadian Science Publishing, 2019) Thakur, Sapna; Choudhary, Shruti; Dubey, Preeti; Bhardwaj, Pankaj
    Arsenic is a widespread toxic metalloid that is classified as a class I carcinogen known to cause adverse health effects in humans. In the present study, we investigated arsenic accumulation potential and comparative gene expression in Indian mustard. The amount of arsenic accumulated in shoots varied in the range of 15.99-1138.70 mg/kg on a dry weight basis among five cultivars. Comparative expression analysis revealed 10?870 significantly differentially expressed genes mostly belonging to response to stress, metabolic processes, signal transduction, transporter activity, and transcription regulator activity to be up-regulated, while most of the genes involved in photosynthesis, developmental processes, and cell growth were found to be down-regulated in arsenic-treated tissues. Further, pathway analysis using the KEGG Automated Annotation server (KAAS) revealed a large-scale reprogramming of genes involved in genetic and environmental information processing pathways. Top pathways with maximum KEGG orthology hits included carbon metabolism (2.5%), biosynthesis of amino acids (2.1%), plant hormone signal transduction (1.4%), and glutathione metabolism (0.6%). A transcriptomic investigation to understand the arsenic accumulation and detoxification in Indian mustard will not only help to improve its phytoremediation efficiency but also add to the control measures required to check bioaccumulation of arsenic in the food chain.
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    Development and chacterization of genomic microsatellite markers in rhdodendron arboreum
    (Central University of Punjab, 2014) Choudhary, Shruti; Bhardwaj, Pankaj
    Rhododendron arboreum, a key species inhabiting Indian Himalayas, has ecological and economic importance. Global climate change and anthropogenic activities can pose a threat to the biodiversity richness. Population genetics characteristics are the fundamentals of conservation and management practices. However, no genetic background for the species is presently available. To provide an insight into the population structure of the species, an effective marker resource was developed. A genomic library enriched for microsatellites was constructed using biotin- streptavidin hybridization technique, followed by sequencing of positive clones. With 54% enrichment rate, 41 primers were designed from SSR clones, consisting of perfect or interrupted repeats of AG/CT, AC/GT motifs. 38 loci showed successful amplification on genotypes of three populations with number of alleles ranging from 2 to 14, observed and expected heterozygosity of 0.167 to 0.933 and 0.422 to 0.917, respectively and average polymorphic information content of 0.104 to 0.811. A high gene flow (Nm= 5.436) demonstrated high genetic diversity within the populations. 19 loci displayed significant deviations from Hardy Weinberg equilibrium. Overall no linkage disequilibrium and bottleneck was detected among sampled populations. DARwin and STRUCTURE analysis grouped the populations into two original clusters and admixed genetic stock irrespective of their geographical locations. These novel loci will support further genotyping studies in R. arboreum.
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    Development and characterization of genomic microsatellite markers in Prosopis cineraria
    (Elsevier B.V., 2017) Anand, Shashi Shekhar; Thakur, Sapna; Gargi, Madhuranjana; Choudhary, Shruti; Bhardwaj, Pankaj; Anand, S.S.; Thakur, S.; Gargi, M.; Choudhary, S.; Bhardwaj, P.
    Characterization of genetic diversity is a must for exploring the genetic resources for plant development and improvement. Prosopis cineraria is ecologically imperative species known for its innumerable biological benefits. Since there is a lack of genetic resources for the species, so it is crucial to unravel the population dynamics which will be very effective in plant improvement and conservation strategies. Of the 41 genomic microsatellite markers designed from (AG)n enriched library, 24 were subsequently employed for characterization on 30 genotypes of Indian arid region. A total of 93 alleles with an average 3.875 could be amplified by tested primer pairs. The average observed and expected heterozygosity was 0.5139 and 0.5786, respectively with 23 primer pairs showing significant deviations from Hardy-Weinberg equilibrium. Polymorphic information content average to 0.5102 and the overall polymorphism level was found to be 93.27%. STRUCTURE analysis and DARwin exhibited the presence of 4 clusters among 30 genotypes. ? 2017 The Authors
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    Development and characterization of genomic microsatellite markers in Rhododendron arboreum
    (Kluwer Academic Publishers, 2014) Choudhary, Shruti; Thakur, Sapna; Saini, Ram Gopal; Bhardwaj, Pankaj; Choudhary, S.; Thakur, S.; Saini, R.G.; Bhardwaj, P.
    Population genetics characteristics are the fundamentals of conservation and management practices. Rhododendronarboreum, a key biodiversity component inhabiting Indian Himalayas, suffers from overexploitation and global warming. Using biotin?streptavidin hybridization technique, 41 microsatellite markers were designed from an enriched DNA library to provide a genetic background and an insight into the population structure of the species. With a range of 2?14 alleles amplified from 38 loci, the populations were reported with observed and expected heterozygosity of 0.167?0.933 and 0.422?0.917 respectively. Some of the loci showed significant deviations from Hardy?Weinberg equilibrium and overall no linkage disequilibrium was detected. These markers will support genetic diversity and further genotyping studies in R. arboreum. ? 2014, Springer Science+Business Media Dordrecht.
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    Development and characterization of genomic microsatellite markers in Tinospora cordifolia
    (Springer India, 2017) Gargi, Madhuranjana; Thakur, Sapna; Anand, Shashi Shekhar; Choudhary, Shruti; Bhardwaj, Pankaj; Gargi, M.; Thakur, S.; Anand, S.S.; Choudhary, S.; Bhardwaj, P.
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    Exploring microRNA profiles for circadian clock and flowering development regulation in Himalayan Rhododendron
    (Elsevier, 2018) Choudhary, Shruti; Thakur, Sapna; Majeed, Aasim; Bhardwaj, Pankaj
    miRNA is a non-coding, yet crucial entity in remodeling the genetic architecture. Rhododendron arboreum of Himalayas grows and even flower under fluctuating climate. sRNA from leaves of vegetative and reproductive periods was sequenced to elucidate its seasonal associations. Conserved (256) and novel (210) miRNAs and their precursors were located based on homology with plant databases and transcriptome of the species. 27,139 predicted targets were involved with metabolism, reproduction, and response to abiotic stimuli. A comparative analysis showed differential expression of 198 miRNAs with season-specific abundance of 103 miRNAs. Specific isoforms of 11 miRNA families exhibited a temporal expression and targeted different genes implying a complex regulation. The variable miRNA expression among the tissues of different conditions can be associated with the adaptability of the species, which will prove essential for further study on miRNAs mediating seasonal response. Moreover, exogenous cues also mediate phase transition via networking of flowering pathways and their components. In this context, 18 known families and 77 novel miRNAs modulating 117 genes crucial in circadian entrainment were filtered. A negative correlation was obtained between the expression of 18 of these miRNAs and their targets when tested through quantitative-PCR. It highlighted the role of miRNA-target pairs in perceiving environmental variabilities and monitoring flowering growth. Furthermore, a phylogenetic clustering was performed, which supported the lineage-specific evolution and function of putative miR156 sequence in the species. This documentation of genome-wide profiling of miRNA, their targets, and expression will enhance the understanding of developmental and climate-tolerance strategies in high-altitude trees.
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    Genetic diversity and population structure of Melia azedarach in North-Western Plains of India
    (Springer Verlag, 2016) Thakur, Sapna; Choudhary, Shruti; Singh, Amandeep; Ahmad, Kamal; Sharma, Gagan; Majeed, Aasim; Bhardwaj, Pankaj
    Key message: Genetic structure amongM. azedarachpopulations was detected and two subpopulations were present among them. A significant ?isolation by distance? was found inM. azedarachpopulation in North-Western Plains of India. Abstract: Melia azedarach is an important forest tree with pharmaceutical, insecticidal, pesticidal, and commercial significance. It is a good reforestation tree because of its fast growth and drought hardy nature. Genetic variation in a species allows itself to adapt, evolve and respond to environmental stress. It provides the basis for survival of a species and critically influences its evolutionary potential. Assessment of genetic diversity is necessary for improvement and conservation of a species. For this, microsatellite markers are of particular interest given the attributes like co-dominance, reproducibility, hyper variability and abundance throughout the genome. In the present study, we analyzed the genetic diversity and population structure of M. azedarach, an ecologically imperative species growing in the North-Western Plains of India. We developed 43 microsatellite markers, of which 20 were subsequently employed for analysis of diversity and population structure among 33 populations encompassing 318 genotypes representing North-Western Plains of India. A moderate level of diversity (Na?=?5.1, Ho?=?0.506, He?=?0.712, I?=?1.386) was assessed. The highest value of ?K estimated using STRUCTURE indicated 2 subpopulations (K?=?2). AMOVA exhibited 73?% variation within populations and 12?% variation was found among regions. Significant positive correlation between geographical and genetic distance was found (Rxy?=?0.365, P?=?0.010). The present study lays a foundation on a better understanding of genetic dynamics of the species and reveals its diversity and population structure in North-Western Plains of India. ? 2016, Springer-Verlag Berlin Heidelberg.
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    Studies on adaptive environmental responses in Himalayan Rhododendron arboreum
    (Central University of Punjab, 2019) Choudhary, Shruti; Bhardwaj, Pankaj
    Temperate plants acclimatize to survive freezing temperatures, which are otherwise prerequisite in the initiation/transition of a developmental phase. The dominance of Rhododendron arboreum under a highly fluctuating Himalayan environment makes it enticing for genetic structure and functional analysis. In the present study, transcript, small RNA and metabolome libraries from flowers and foliar tissues of reproductive and vegetative seasons were analyzed. The high-quality paired-end reads were assembled into 157,427 non-redundant transcripts and categorized functionally based on gene ontology, pathway, and transcription factor database. The screening for molecular markers identified 35,419 SSR and 811 high-quality SNPs. A comparison of transcript profiles for the vegetative and flowering season tissues revealed that 12,577 unigenes with fluctuating expression were responsible for seasonal adaptations. Additional to the gene interaction networks, 421 ions obtained from LC-MS were annotated to distinct pathways, especially secondary metabolites. Thirdly, 466 conserved and novel miRNAs, 442 precursors, and 27,139 targets were predicted and the miRNAs modulating circadian clock and reproductive development were discussed further. Other than the genes, miRNAs, and compounds held for an active metabolism, signaling, development, and their regulations, supplementary responses to abiotic/biotic stimuli were induced. A multifaceted response not only sponsored the climatic encounters but brought the shift from vegetative to reproductive growth. The genome-wide profiling and the spatiotemporal variation in mRNA and miRNA expression, as well as the nontargeted metabolome, will enhance the understanding of development and tolerance strategies in high altitude tree species.