Publications of NIPGR Scientists

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Author: search.filters.author.Choudhary, AanchalSubject: search.filters.subject.Combined stress

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Now showing 1 - 4 of 4
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    The war for apoplastic water: stomatal control as a key strategy in bacterial pathogenesis
    (Springer Nature Publishing AG, 2023) Choudhary, Aanchal; Senthil-Kumar, Muthappa
    In this commentary, important recent discoveries on effector-mediated manipulation of apoplast hydration and the involvement of ABA machinery that are targeted in later stages of bacterial infection culminating in stomatal closure are highlighted. This article also sheds light on the differences in early and later stages of infection wherein the COR signaling in the initial phase promotes stomatal opening while in later stages ABA signaling overrides and forces the stomata to close. Also, the current understanding of pathogen-driven modulation of leaf water status during infection, in which stomata act as a crucial battleground between pathogens and plants at the post-invasive stage is summarized.
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    Investigation of the novel transcriptional changes under combined drought and bacterial stress underpins the role of AtMYB96 in imparting tolerance
    (Springer Nature Publishing AG, 2021) Choudhary, Aanchal; Senthil-Kumar, Muthappa
    The physiological and molecular responses instigated to combat drought and bacterial pathogens often work antagonistically and, in most cases, the impact of combined stress is more detrimental to plant growth. Interestingly, plants exposed to this stress combination show a novel transcriptome fingerprint with a significant set of genes that are uniquely altered under combined stress. Despite this being reported in several transcriptomic datasets, our molecular understanding of these combined stress-specific genes and pathways is still in its nascent stages. These unique genes and the dedicated regulatory pathways are important for understanding the molecular aspects of signaling responses under combined stress. In this study, a previously available microarray dataset was extensively reanalysed to identify the novel genes and pathways specifically altered under combined stress. Using a combination of bioinformatic and data-guided approaches, we identified major biological pathways, transcription factor (TF) network and novel motifs potentially involved in the combined stress-specific responses. The candidate gene analysis using gene expression and mutant analysis identified AtMYB96 as an important TF involved in combined stress response. Taken together, our analysis pinpoints many novel genes that can be used for understanding the molecular mechanism of how plants deal with the combination of drought and bacterial pathogen.
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    Transcriptomic changes under combined drought and nonhost bacteria reveal novel and robust defenses in Arabidopsis thaliana
    (Elsevier B.V., 2017) Choudhary, Aanchal; Gupta, Aarti; Ramegowda, Venkategowda; Senthil-Kumar, Muthappa
    Plants in the natural conditions are often challenged by a combination of two or more stressors. A combination of drought and pathogen is one of the most pressing threats to the plant’s growth and survival in the field, and thus warrants a mechanistic understanding. Susceptible plant-pathogen interaction, owing to effector-mediated suppression of plant defense responses, limits its scope for combined stress studies. In the present study, we have investigated the morpho-physiological responses of Arabidopsis thaliana to simultaneous drought and nonhost bacterial pathogen Pseudomonas syringae pv. tabaci. Combined stress treatment provoked an early and more pronounced hypersensitive response in the plant as compared to the non-host pathogen treatment. We have further deciphered the molecular basis for the robust defense response observed under combined stress by transcriptomic profiling carried out using whole-genome microarray. We found that the enhanced resistance to the combined stress is accompanied by a massive transcriptional reprogramming involving several transcripts specifically responding to the stress combination. A prominent over-representation of genes involved in basal defense-related machinery was observed under the combined stress. Genes involved in various defense signaling cascades, accumulation of secondary metabolites and those encoding for receptor-like kinases were highly up-regulated under the combined stress. Up-regulated genes related to redox homeostasis and hypersensitive response (HR)-mediated cell death were also found to be markedly enriched under combined stress. We also compared the global gene expression profile of A. thaliana subjected to combined drought-nonhost bacteria to those treated with a combination of drought-host bacteria Pseudomonas syringae pv. tomato DC3000. A significant induction of genes responding to drought as well as bacteria was observed during both the interactions. However, the amplitude of induction was more pronounced under the combination of drought and nonhost bacteria. Our results also indicate that plant activates multiple defense pathways upon exposure to combined stress which strengthens the overall basal immunity of the plant, characterized by a stronger HR response.
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    Tailored responses to simultaneous drought stress and pathogen infection in plants
    (Springer, 2016) Choudhary, Aanchal; Pandey, Prachi; Senthil-Kumar, Muthappa
    Under field conditions plants are often challenged by combination of biotic and abiotic stressors and they severely affect crop productivity. An increasing number of studies suggest that plants “tailor” their adaptation strategies to combat simultaneously occurring stresses. The stress combat strategies of plants are customized according to the stress combination and vary with the intensity and timing of the stresses involved. While some of the responses seen under combined stress are commonly instigated by individual stresses, some other are uniquely triggered under combined stress. Since some responses are unique only to the combined stress, the outcome of a stress interaction cannot be completely predicted using results from individual stress studies. In this chapter, the effects of combinatorial drought stress and pathogen infection on plants are discussed with an emphasis on the molecular and physiological mechanisms that underpin how plants tolerate simultaneously occurring stresses. We also highlight the complexity involved in the responses of plants to multiple stresses and underscore the importance of studying plant stressors in combination.