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Author: search.filters.author.Prasad, ManojSubject: search.filters.subject.Epigenetics

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Now showing 1 - 8 of 8
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    DNA methylation dynamics in response to abiotic and pathogen stress in plants
    (Springer Nature Publishing AG, 2022) Arora, Heena; Singh, Roshan Kumar; Sharma, Shambhavi; Sharma, Namisha; Panchal, Anurag; Das, Tuhin; Prasad, Ashish; Prasad, Manoj
    DNA methylation is a dynamic epigenetic mechanism that plays a significant role in gene expression and also maintains chromatin stability. The process is conserved in both plants and animals, and crucial for development and stress responses. Differential DNA methylation during adverse environmental conditions or pathogen attack facilitates the selective expression of defense-related genes. Both stress-induced DNA hypomethylation and hypermethylation play beneficial roles in activating the defense response. These DNA marks may be carried to the next generation making the progenies ‘primed’ for abiotic and biotic stress responses. Over the recent years, rapid advancements in the area of high throughput sequencing have enabled the detection of methylation status at genome levels in several plant species. Epigenotyping offers an alternative tool to plant breeders in addition to conventional markers for the selection of the desired offspring. In this review, we briefly discuss the mechanism of DNA methylation, recent understanding of DNA methylation-mediated gene regulation during abiotic and biotic stress responses, and stress memory in plants.
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    Histone acetylation dynamics regulating plant development and stress responses
    (Springer Nature Publishing AG, 2021) Kumar, Verandra; Thakur, Jitendra K.; Prasad, Manoj
    Crop productivity is directly dependent on the growth and development of plants and their adaptation during different environmental stresses. Histone acetylation is an epigenetic modification that regulates numerous genes essential for various biological processes, including development and stress responses. Here, we have mainly discussed the impact of histone acetylation dynamics on vegetative growth, flower development, fruit ripening, biotic and abiotic stress responses. Besides, we have also emphasized the information gaps which are obligatory to be examined for understanding the complete role of histone acetylation dynamics in plants. A comprehensive knowledge about the histone acetylation dynamics will ultimately help to improve stress resistance and reduce yield losses in different crops due to climate changes.
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    Surfacing the role of epigenetics in host-virus interaction
    (Caister Academic Press, 2018) Sharma, Namisha; Sahu, Pranav P.; Kulshreshtha, Ritika; Prasad, Manoj
    Epigenetics is a mechanism which determines the phenotype of an organism by causing heritable (during cell division) but simultaneously reversible alterations/variations in gene expression. It is not related to alterations in the DNA sequence of the genotype. Geminiviruses are the most devastating plant viruses since they cause significant yield losses in world agriculture. The plant defense initiated against these DNA viruses is of special interest, specifically in regard to the role of epigenetic mechanism played in control of virus spread. These heritable and covalent modifications of DNA and histone in virus genome are mainly related to suppression of gene transcription, despite the differences between viruses, the role of epigenetics seems to be reasonably comparable. However, several key questions remain unanswered concerning the basic mechanism behind the epigenetic regulation of viruses via plant defense system. This book chapter specifically summarizes the recent advances on role of epigenetics in virus genome modification leading to silencing of viral genes and plant tolerance/resistance.
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    An insight into plant–Tomato leaf curl New Delhi virus interaction
    (Springer Nature, 2017) Sharma, Namisha; Prasad, Manoj
    Plants being sessile are constantly exposed to several stresses, which involve different types of abiotic and biotic stress factors. Biotic stress in plants is caused by various living organisms called plant pathogens including bacteria, viruses, fungi and parasites. Among these pathogens, plant viruses cause severe damage to world agricultural productivity. The reason behind such widespread destruction caused by viruses is their ability to frequently evolve them through mutation and genetic recombination, to succeed over the unfavourable conditions. The virus infects both susceptible and tolerant/resistant plants by the similar and systematic manner but resistant/tolerant plants combat the virus spread and suppress the viral growth. When pathogen enters the plant system, diverse defense responses are initiated which are mediated by plant disease resistance genes (R genes) mediated resistance and hormone based signaling pathways which restrict the viral spread by initiating hypersensitive response. To further enhance our knowledge regarding resistance mechanisms, the virus infection pattern and interactions of virus within resistant and susceptible plants needs to be analysed. At present, most successful strategy involves deployment of crops possessing resistance/tolerance against viruses with the foremost interest of detecting genes associated with resistance or recovery. Among several plant viruses, ‘Geminiviruses’ are the most devastating. In this article we have provided a comprehensive overview of Tomato leaf curl New Delhi virus (ToLCNDV), a member of family Geminiviridae and the plant defense system initiated against this virus. The evaluation of ToLCNDV infection in a variety of hosts differing in their tolerance and identification of differentially expressed genes would be helpful in speculating the threats associated with similar begomoviral invasions.
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    Salinity induced differential methylation patterns in contrasting cultivars of foxtail millet (Setaria italica L.)
    (Springer, 2017) Pandey, Garima; Yadav, Chandra Bhan; Sahu, Pranav Pankaj; Muthamilarasan, Mehanathan; Prasad, Manoj
    Reduced productivity and significant yield loss are the adverse effects of environmental conditions on physiological and biochemical pathways in crop plants. In this context, understanding the epigenetic machinery underlying the tolerance traits in a naturally stress tolerant crop is imperative. Foxtail millet (Setaria italica) is known for its better tolerance to abiotic stresses compared to other cereal crops. In the present study, methylation-sensitive amplified polymorphism (MSAP) technique was used to quantify the salt-induced methylation changes in two foxtail millet cultivars contrastingly differing in their tolerance levels to salt stress. The study highlighted that the DNA methylation level was significantly reduced in tolerant cultivar compared to sensitive cultivar. A total of 86 polymorphic MSAP fragments were identified, sequenced and functionally annotated. These fragments showed sequence similarity to several genes including ABC transporter, WRKY transcription factor, serine threonine-protein phosphatase, disease resistance, oxidoreductases, cell wall-related enzymes and retrotransposon and transposase like proteins, suggesting salt stress-induced methylation in these genes. Among these, four genes were chosen for expression profiling which showed differential expression pattern between both cultivars of foxtail millet. Altogether, the study infers that salinity stress induces genome-wide DNA demethylation, which in turn, modulates expression of corresponding genes.
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    Post-transcriptional and epigenetic arms of RNA silencing: a defense machinery of naturally tolerant tomato plant against Tomato leaf curl New Delhi virus
    (Springer, 2014) Sahu, Pranav Pankaj; Sharma, Namisha; Puranik, Swati; Prasad, Manoj
    Tomato leaf curl disease (ToLCD), caused by strains of Tomato leaf curl virus, is major constraint to tomato production globally. The present study was aimed to understand the mechanisms of ToLCD tolerance in a naturally tolerant tomato cultivar through post-transcriptional and DNA methylation-specific RNA silencing. We evaluated the distribution of virus-derived short-interfering RNAs (siRNAs) throughout the Tomato leaf curl New Delhi virus (ToLCNDV) genome along with DNA methylation patterns in intergenic (IR) and Rep (AC1) regions in two tomato cultivars differing in their ToLCNDV tolerance. The methylation pattern was correlated by expression analysis of key methyltransferases genes. In the tolerant cultivar, higher accumulation of viral IR-specific 24-nucleotides (nt) siRNA and AC1-specific 21-nt siRNA were found. Higher methylation levels were observed in various regions of IR. Additionally, AC1 region which facilitates binding of plant nuclear proteins was hypermethylated. DNA methylation in the key regulating region may control the expression of AC1, AC2, and AC3 genes. Components of RNA silencing and DNA methylation machinery were found to be differentially expressed in both the cultivar of tomato at 21 dpi. Thus, we infer that both viral DNA methylation and siRNA-mediated RNA degradation play an important role in conferring tolerance against Tomato leaf curl New Delhi virus. Due to the inability to achieve field resistance in transgenic tomato by deploying the viral genes, targeting the viral genomic regions through RNAi technology reported here could offer an alternate defense strategy for generating transgenics to prevent yield loss.
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    Involvement of host regulatory pathways during geminivirus infection: a novel platform for generating durable resistance
    (Springer, 2014) Sahu, Pranav Pankaj; Sharma, Namisha; Puranik, Swati; Muthamilarasan, Mehanathan; Prasad, Manoj
    Geminiviruses are widely distributed throughout the world and cause devastating yield losses in almost all the economically important crops. In this review, the newly identified roles of various novel plant factors and pathways participating in plant–virus interaction are summarized with a particular focus on the exploitation of various pathways involving ubiquitin/26S proteasome pathway, small RNA pathways, cell division cycle components, and the epigenetic mechanism as defense responses during plant–pathogen interactions. Capturing the information on these pathways for the development of strategies against geminivirus infection is argued to provide the basis for new genetic approaches to resistance.
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    Epigenetic mechanisms of plant stress responses and adaptation
    (Springer, 2013) Sahu, Pranav Pankaj; Pandey, Garima; Sharma, Namisha; Puranik, Swati; Muthamilarasan, Mehanathan; Prasad, Manoj
    Epigenetics has become one of the hottest topics of research in plant functional genomics since it appears promising in deciphering and imparting stress-adaptive potential in crops and other plant species. Recently, numerous studies have provided new insights into the epigenetic control of stress adaptation. Epigenetic control of stress-induced phenotypic response of plants involves gene regulation. Growing evidence suggest that methylation of DNA in response to stress leads to the variation in phenotype. Transposon mobility, siRNA-mediated methylation and host methyltransferase activation have been implicated in this process. This review presents the current status of epigenetics of plant stress responses with a view to use this knowledge towards engineering plants for stress tolerance.