Browsing by Author "Nandi, Ashis Kumar"

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    CBL-interacting protein kinase 6 negatively regulates immune response to Pseudomonas syringae in Arabidopsis
    (Oxford University Press, 2017) Sardar, Atish; Nandi, Ashis Kumar; Chattopadhyay, Debasis
    Cytosolic calcium ion (Ca2+) is an essential mediator of the plant innate immune response. Here, we report that a calcium-regulated protein kinase Calcineurin B-like protein (CBL)-interacting protein kinase 6 (CIPK6) functions as a negative regulator of immunity against the bacterial pathogen Pseudomonas syringae in Arabidopsis thaliana. Arabidopsis lines with compromised expression of CIPK6 exhibited enhanced disease resistance to the bacterial pathogen and to P. syringae harboring certain but not all avirulent effectors, while restoration of CIPK6 expression resulted in abolition of resistance. Plants overexpressing CIPK6 were more susceptible to P. syringae. Enhanced resistance in the absence of CIPK6 was accompanied by increased accumulation of salicylic acid and elevated expression of defense marker genes. Salicylic acid accumulation was essential for improved immunity in the absence of CIPK6. CIPK6 negatively regulated the oxidative burst associated with perception of pathogen-associated microbial patterns (PAMPs) and bacterial effectors. Accelerated and enhanced activation of the mitogen-activated protein kinase cascade in response to bacterial and fungal elicitors was observed in the absence of CIPK6. The results of this study suggested that CIPK6 negatively regulates effector-triggered and PAMP-triggered immunity in Arabidopsis.
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    Systemic acquired resistance specifc proteome of Arabidopsis thaliana
    (Springer Nature Publishing AG, 2020) Kumar, Rajiv; Barua, Pragya; Chakraborty, Niranjan; Nandi, Ashis Kumar
    Key message A comparative proteomic study between WT and SAR-compromised rsi1/fd mutant reveals a set of proteins having possible roles in the SAR development. Abstract A partly infected plant shows enhanced resistance during subsequent infection through the development of systemic acquired resistance (SAR). Mobile signals generated at the site of primary infection travel across the plant for the activation of SAR. These mobile signals are likely to cause changes in the expression of a set of proteins in the distal tissue, which contributes to the SAR development. However, SAR-specifc proteome is not revealed for any plant. The reduced systemic immunity 1 (rsi1)/(allelic to fowering locus D; fd) mutant of Arabidopsis is compromised for SAR but shows normal local resistance. Here we report the SAR-specifc proteome of Arabidopsis by comparing diferentially abundant proteins (DAPs) between WT and fd mutant. Plants were either mock-treated or SAR-induced by primary pathogen inoculation. For proteomic analysis, samples were collected from the systemic tissues before and after the secondary inoculation. Protein identifcation was carried out by using two-dimensional gel electrophoresis (2-DE) followed by tandem mass spectrometry. Our work identifed a total of 94 DAPs between mock and pathogen treatment in WT and fd mutant. The DAPs were categorized into diferent functional groups along with their subcellular localization. The majority of DAPs are involved in metabolic processes and stress response. Among the subcellular compartments, plastids contained the highest number of DAPs, suggesting the importance of plastidic proteins in SAR activation. The fndings of this study would provide resources to engineer efcient SAR activation traits in Arabidopsis and other plants.