Publications of NIPGR Scientists

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Author: search.filters.author.Mathur, SaloniSubject: search.filters.subject.Drought

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    Deciphering the role of MIR169d:NF-YA2 module under individual as well as combined drought and heat stress in Arabidopsis
    (Springer Nature Publishing AG, 2024) Gupta, Apoorva; Ghosh, Debasish; Rao, Sombir; Mathur, Saloni
    Plants are often subjected to a combination of abiotic stresses under natural environmental conditions. The response of plants to combined stresses can be very diferent from that to the individual stress. Several regulatory mechanisms work in harmony to maintain plant’s homeostasis during stress conditions. Among them the roles of microRNAs (miRNAs) in combined stresses are beginning to be unravelled. In this study, we evaluated the MIR169d: NF-YA2 target module in individual as well as combined drought and heat stress (HS) in Arabidopsis. We found that MIR169d is highly HS inducible, however, contrary to the reported downregulation of MIR169a/c forms in drought stress in literature, MIR169d is upregulated in drought. Moreover, while MIR169d expression is upregulated during combined stress, the response is less than individual stresses. Further, Arabidopsis plants overexpressing MIR169d or target nf-ya2 knockout mutant plants are more tolerant to both individual as well as combined heat and drought stress as indicated by the higher expression of stress responsive genes and less Trypan blue staining, while plants overexpressing NF-YA2 or those in which miR169defg isoform is sponged up (MIM169defg) are more prone to individual as well as combined heat and drought stress. The MIR169d promoter harbours both heat and drought stress-responsive cis-elements. Assessment of GUS expression in MIR169d-promoter:GUS and NF-YA2-promoter:GUS transgenic lines shows increased and reduced reporter expression in all the three stress conditions as compared to control, respectively. This suggests a stress-induced transcriptional regulation of the MIR169d:NF-YA2 pair. Thus, the MIR169d:NF-YA2 module can be potentially exploited to engineer crops for resistance to multiple abiotic stresses.
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    Inferring the regulatory network of the miRNA-mediated response to individual and combined heat and drought stress in tomato
    (Springer Nature Publishing AG, 2021) Bansal, Chandni; Balyan, Sonia; Mathur, Saloni
    Under natural environmental conditions, plants are prone to be challenged simultaneously by combination of stresses like heat and drought stress together, thus affecting their overall growth, development and reproduction. Moreover, future climatic conditions are predicted to be warmer and drier, thus, warranting deep understanding of the stress-responsive regulatory networks for developing stress-management strategies. The role of microRNAs (miRNAs) that are key regulators of different stress signalling cascades in such dual stress conditions using varieties growing in warmer climatic conditions is completely lacking. In this study, we have investigated the effect of drought, heat and the two stresses together (combined stress) on a heat-tolerant tomato (Solanum lycopersicum) variety by evaluating physiological parameters as well as, some stress-responsive miRNA-target modules. Taqman-based qRT-PCR miRNA expression analysis showed enhanced expression of sly-miR482d-3p, sly-miR172d-3p, sly-miR164b-3p, sly-miR398b in individual drought and heat stress with an additive upregulation effect under combined stresses. On the other hand, the expression of sly-miR397-5p and sly-miR396b-3p was less when these two stresses co-occurred than the individual stresses and an antagonistic response was observed for sly-miR166a expression in combined versus single stresses. Several high confidence miRNA targets (101) were identified in-silico using degradome data and were functionally annotated using Gene Ontology enrichment analysis into various stress regulatory networks. The comparative analysis confirmed the inverse expression regulation of the miRNA:target pairs for sly-miR398b:Solyc07g006180, sly-miR164b-3p:Solyc08g061500, sly-miR172d:Solyc04g049800, sly-miR396b-3p:Solyc01g102810 and sly-miR396b-3p:Solyc05g017930 under all the three stress conditions. Since miRNAs are highly conserved across diverse plant species, these miRNAs can be candidates for engineering climate resilient crop plants.
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    Identification of miRNA-mediated drought responsive multi-tiered regulatory network in drought tolerant rice, Nagina 22
    (Nature Publishing Group, 2017) Balyan, Sonia; Kumar, Mukesh; Mutum, Roseeta Devi; Raghuvanshi, Utkarsh; Agarwal, Priyanka; Mathur, Saloni; Raghuvanshi, Saurabh
    Comparative characterization of microRNA-mediated stress regulatory networks in contrasting rice cultivars is critical to decipher plant stress response. Consequently, a multi-level comparative analysis, using sRNA sequencing, degradome analysis, enzymatic and metabolite assays and metal ion analysis, in drought tolerant and sensitive rice cultivars was conducted. The study identified a group of miRNAs "Cultivar-specific drought responsive" (CSDR)-miRNAs (osa-miR159f, osa-miR1871, osa-miR398b, osa-miR408-3p, osa-miR2878-5p, osa-miR528-5p and osa-miR397a) that were up-regulated in the flag-leaves of tolerant cultivar, Nagina 22 (N22) and Vandana, but down-regulated in the sensitive cultivar, Pusa Basmati 1 (PB1) and IR64, during drought. Interestingly, CSDR-miRNAs target several copper-protein coding transcripts like plantacyanins, laccases and Copper/Zinc superoxide dismutases (Cu/Zn SODs) and are themselves found to be similarly induced under simulated copper-starvation in both N22 and PB1. Transcription factor OsSPL9, implicated in Cu-homeostasis also interacted with osa-miR408-3p and osa-miR528-5p promoters. Further, N22 flag leaves showed lower SOD activity, accumulated ROS and had a higher stomata closure. Interestingly, compared to PB1, internal Cu levels significantly decreased in the N22 flag-leaves, during drought. Thus, the study identifies the unique drought mediated dynamism and interplay of Cu and ROS homeostasis, in the flag leaves of drought tolerant rice, wherein CSDR-miRNAs play a pivotal role.
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    Unique miRNome during anthesis in drought-tolerant indica rice var. Nagina 22
    (Springer, 2015) Kansal, Shivani; Devi, Roseeta M.; Balyan, Sonia C.; Arora, Mukesh K.; Singh, Anil K.; Mathur, Saloni; Raghuvanshi, Saurabh
    MAIN CONCLUSION: Drought-tolerant rice variety, Nagina 22 (N22), has a unique spikelet miRNome during anthesis stage drought as well as transition from heading to anthesis. Molecular characterization of genetic diversity of rice is essential to understand the evolution and molecular basis of various agronomically important traits such as drought tolerance. miRNAs play an important role in regulating plant development as well as stress response such as drought. In this study, we characterized the yet unexplored dynamics of the spikelet miRNA population during developmental transition from 'heading' to 'anthesis' as well as anthesis stage drought stress in a drought-tolerant indica rice variety, N22. A significant proportion of miRNA population (~20 %) in N22 spikelets is modulated during transition from heading to anthesis indicating a unique miRNome at anthesis, a developmental stage highly sensitive to stress (drought/heat). Based on the analysis of degradome data, majority of differentially regulated miRNAs appear to regulate transcription factors, some of which are implicated in regulation of development and fertilization. Similarly, drought during anthesis leads to a global change in miRNA expression pattern including those which regulate ROS homeostasis. It was possible to identify several miRNAs that were not reported to be drought responsive in earlier studies. Interestingly, a significant proportion of the drought-regulated miRNAs co-localize within QTLs related to drought tolerance and associated traits. Comparison of the expression profiles between N22 and Pusa Basmati 1 (drought sensitive) identified miRNAs with variety-specific expression patterns during phase transition (miR164, miR396, miR812, and miR1881) as well as drought stress (miR1881) indicating an evolution of a distinct and variety-specific regulatory mechanism. The promoters of these miRNAs contain LREs (light-responsive elements) and are induced by dark treatment. It was also possible to identify 4 novel miRNAs including an intronic miRNA that was conserved in both rice varieties.
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    Insights into the small RNA-mediated networks in response to abiotic stress in plants
    (Springer, 2015) Balyan, Sonia C.; Mutum, Roseeta D.; Kansal, Shivani; Kumar, Santosh; Mathur, Saloni; Raghuvanshi, Saurabh
    Under natural conditions, plants are constantly exposed to various environmental stresses such as drought, extreme temperature, salt, UV, mechanical, or nutrient starvation. To cope with these adverse conditions, plants have evolved cascade of molecular networks to perceive and transduce the stress signals, resulting into the reprogramming of gene expression. The stress-regulated reprogramming of gene expression at post-transcriptional regulation has been emphasized with the discovery of small regulatory RNAs. Plant small RNAs represent non-coding RNAs in the size range of 20–24 nucleotides and categorized into hairpin RNAs (hpRNAs) and siRNAs. The first category includes miRNAs, lmiRNAs, and nat-miRNAs while the siRNA group includes hc-siRNA, secondary siRNAs and nat-siRNAs. Studies have shown that small RNAs, especially miRNAs, are dynamically regulated by a variety of abiotic stress conditions. Such sRNAs target a variety of downstream targets including regulatory proteins as well as metabolic enzymes and thus play pivotal role in the regulation of plant abiotic stress response. Stress appears to regulate miRNA biogenesis as well as its activity. Several miRNA gene:target pairs respond to multiple stress conditions and are conserved in various plant species indicating that miRNAs may define pivotal regulatory nodes involved in the regulation of the plant stress response. On the other hand, miRNAs also show variety-/cultivar-specific stress response indicating that they themselves are under a very dynamic regulation. The world of small RNAs is gradually unfolding and much remains to be explored, nevertheless, it has been conclusively demonstrated that small RNAs define a new dimension in the molecular regulatory network regulating the plant stress response.