Publications of NIPGR Scientists

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Author: search.filters.author.Ghosh, ShraboniSubject: search.filters.subject.Arabidopsis

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    The Arabidopsis F-box protein SKP1-INTERACTING PARTNER 31 modulates seed maturation and seed vigor by targeting JASMONATE ZIM DOMAIN proteins independently of jasmonic acid-isoleucine
    (Oxford University Press, 2023) Varshney, Vishal; Hazra, Abhijit; Rao, Venkateswara; Ghosh, Shraboni; Kamble, Nitin Uttam; Achary, Rakesh Kumar; Gautam, Shikha; Majee, Manoj
    F-box proteins have diverse functions in eukaryotic organisms, including plants, mainly targeting proteins for 26S proteasomal degradation. Here, we demonstrate the role of the F-box protein SKP1-INTERACTING PARTNER 31 (SKIP31) from Arabidopsis (Arabidopsis thaliana) in regulating late seed maturation events, seed vigor, and viability through biochemical and genetic studies using skip31 mutants and different transgenic lines. We show that SKIP31 is predominantly expressed in seeds and that SKIP31 interacts with JASMONATE ZIM DOMAIN (JAZ) proteins, key repressors in jasmonate (JA) signaling, directing their ubiquitination for proteasomal degradation independently of coronatine/jasmonic acid-isoleucine (JA-Ile), in contrast to CORONATINE INSENSITIVE 1, which sends JAZs for degradation in a coronatine/JA-Ile dependent manner. Moreover, JAZ proteins interact with the transcription factor ABSCISIC ACID-INSENSITIVE 5 (ABI5) and repress its transcriptional activity, which in turn directly or indirectly represses the expression of downstream genes involved in the accumulation of LATE EMBRYOGENESIS ABUNDANT proteins, protective metabolites, storage compounds, and abscisic acid biosynthesis. However, SKIP31 targets JAZ proteins, deregulates ABI5 activity, and positively regulates seed maturation and consequently seed vigor. Furthermore, ABI5 positively influences SKIP31 expression, while JAZ proteins repress ABI5-mediated transactivation of SKIP31 and exert feedback regulation. Taken together, our findings reveal the role of the SKIP31-JAZ-ABI5 module in seed maturation and consequently, establishment of seed vigor.
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    A protein repairing enzyme, PROTEIN L- ISOASPARTYL METHYLTRANSFERASE is involved in salinity stress tolerance by increasing efficiency of ROS-scavenging enzymes
    (Elsevier B.V., 2020) Ghosh, Shraboni; Kamble, Nitin Uttam; Majee, Manoj
    Saline conditions can significantly affect plant growth and development, leading to massive reduction in crop yield. Herein, we show that a protein repairing enzyme PROTEIN L-ISOASPARTYL METHYLTRANSFERASE imparts salinity stress tolerance in Arabidopsis thaliana by repairing deleterious isoAsp accumulation during salinity stress. We demonstrate that salinity stress accelerates isoAsp accumulation in proteins and also induces PIMT activity in Arabidopsis. Transcript analysis indicates that both PIMT1 and PIMT2 are upregulated in response to salinity stress. Subsequent functional analysis reveals that PIMT1 and PIMT2 overexpression lines are tolerant, while RNAi lines are hyper sensitive to salinity stress in comparison to wild type (WT). Biochemical analyses of thesePIMT transgenic lines also reveals that compromised salinity tolerance of RNAi lines are linked to increased isoAsp accumulation, while improved tolerance of overexpression lines is associated with reduced isoAsp accumulation in proteins. Histochemical and biochemical studies further confirm lower accumulation of ROS and reduced lipid peroxidation in PIMT overexpression lines, while increased ROS accumulation and increased lipid peroxidation in RNAi lines as compared to WT under salinity stress. Interestingly, PIMToverexpression lines exhibit improved antioxidant enzyme efficiency, while RNAi lines display compromised antioxidant enzyme efficacy as compared to WT type plants. Our study suggests that PIMT improves salinity stress tolerance by restricting salt induced-excess ROS accumulation possibly by repairing isoAsp mediated protein damage of antioxidant enzymes. Our study can be utilized for enhancing salinity stress tolerance of economically important crops.
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    Arabidopsis Protein L-Isoaspartyl Methyltransferase repairs isoaspartyl damage to antioxidant enzymes and increases heat and oxidative stress tolerance
    (American Society for Biochemistry and Molecular Biology, 2020) Ghosh, Shraboni; Kamble, Nitin Uttam; Verma, Pooja; Salvi, Prafull; Petla, Bhanu Prakash; Roy, Shweta; Rao, Venkateswara; Hazra, Abhijit; Varshney, Vishal; Kaur, Harmeet; Majee, Manoj
    Stressful environments accelerate the formation of isoaspartyl (isoAsp) residues in proteins, which detrimentally affect protein structure and function. The enzyme Protein L-Isoaspartyl Methyltransferase (PIMT) repairs other proteins by reverting deleterious isoAsp residues to functional aspartyl residues. PIMT function previously has been elucidated in seeds, but its role in plant survival under stress conditions remains undefined. Herein, we used molecular, biochemical, and genetic approaches, including protein overexpression and knockdown experiments, in Arabidopsis to investigate the role of PIMTs in plant growth and survival during heat and oxidative stresses. We demonstrate that these stresses increase isoAsp accumulation in plant proteins, that PIMT activity is essential for restricting isoAsp accumulation, and that both PIMT1 and PIMT2 play an important role in this restriction and Arabidopsis growth and survival. Moreover, we show that PIMT improves stress tolerance by facilitating efficient reactive oxygen species (ROS) scavenging and thereby protecting the functionality of antioxidant enzymes from isoAsp-mediated damage during stress. Specifically, biochemical and MS/MS analyses revealed that antioxidant enzymes acquire deleterious isoAsp residues during stress, which adversely affect their catalytic activities, and that PIMT repairs the isoAsp residues and thereby restores antioxidant enzyme function. Collectively, our results suggest that the PIMT-mediated protein repair system is an integral part of the stress tolerance mechanism in plants, in which PIMTs protect antioxidant enzymes that maintain proper ROS homeostasis against isoAsp-mediated damage in stressful environments.