Institutional Publications

Permanent URI for this collectionhttps://ndkr-library.nipgr.ac.in/handle/123456789/11

Browse

Author: search.filters.author.Majee, ManojSubject: search.filters.subject.Arabidopsis

Search Results

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    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.
  • No Thumbnail Available
    Item
    Seed germination variability: Why do genetically identical seeds not germinate at the same time?
    (Oxford University Press, 2023) Sharma, Eshan; Majee, Manoj
    For survival in the wild environment, plants prefer a bet-hedging strategy where individual variation is high and also produce a range of phenotypes. When faced with unpredictable environmental conditions, fluctuation in seed behaviour is a beneficial trait that allows the survival of plants, particularly if seedlings from early germinated seeds don't survive. However, this is not a desired trait when agriculture is concerned, where a set of uniformly grown seedlings are required. Even though variability in seed behaviour is unavoidable, over the centuries, humans might have selected seeds with minimum variability for agricultural use. In the model plant Arabidopsis, non-stratified seeds even in the same silique germinate variably. How this variability is manifested from genes to a physiological outcome and what molecular mechanism of bet-hedging facilitates this diversity remains elusive. Will the reintroduction of valuable wild alleles in domesticated crops contribute to this variability between individual seeds by promotion of bet-hedging? Recent advances have shed light on possible molecular pathways of germination that are impacted at the level of single seeds and single cells. Here, we review the hormonal, molecular and cellular mechanisms that may impact the germination outcome of individual genetically identical seeds.
  • Thumbnail Image
    Item
    Sequestering miR165/166 enhances seed germination in Arabidopsis thaliana under normal condition and ABA treatment
    (Springer Nature Publishing AG, 2020) Sarkar Das, Shabari; Majee, Manoj; Nandi, Asis K.; Karmakar, Prakash
    Seed germination is a dynamic process involving imbibition, increased metabolic activity and protrusion of a tiny plantlet rupturing the seed coat. Many genes, phytohormones like ABA and GA have been implicated in germination of Arabidopsis thaliana seeds. Although many microRNAs (miRNAs) have been shown to be differentially expressed during seed germination process, their role remains mostly unaddressed. Here we address the role of developmentally important miR165/166 in the process of seed germination. We demonstrate that the seeds of transgenic A. thaliana having target mimic-miR165/166 (eTM-miR165/166), where miR165/166 is sponged, show better germination efficiency. The seeds of this line also maintain better germination even under ABA treatment, which is a negative regulator of seed germination. Thus, our results suggest that, sequestering miR165/166 activity enhances seed germination efficiency under normal and ABA-stress condition.
  • Thumbnail Image
    Item
    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.
  • Thumbnail Image
    Item
    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.
  • Thumbnail Image
    Item
    Light-induced phosphorylation and degradation of the negative regulator PIF1 depends upon its direct physical interactions with photoactivated phytochromes
    (American Society of Plant Biologists, 2008) Shen, Hui; Zhu, Ling; Castillon, Alicia; Majee, Manoj; Downie, Bruce; Huq, Enamul
    The phytochrome (phy) family of photoreceptors regulates changes in gene expression in response to red/far-red light signals in part by physically interacting with constitutively nucleus-localized phy-interacting basic helix-loop-helix transcription factors (PIFs). Here, we show that PIF1, the member with the highest affinity for phys, is strongly sensitive to the quality and quantity of light. phyA plays a dominant role in regulating the degradation of PIF1 following initial light exposure, while phyB and phyD and possibly other phys also influence PIF1 degradation after prolonged illumination. PIF1 is rapidly phosphorylated and ubiquitinated under red and far-red light before being degraded with a half-life of ~1 to 2 min under red light. Although PIF1 interacts with phyB through a conserved active phyB binding motif, it interacts with phyA through a novel active phyA binding motif. phy interaction is necessary but not sufficient for the light-induced phosphorylation and degradation of PIF1. Domain-mapping studies reveal that the phy interaction, light-induced degradation, and transcriptional activation domains are located at the N-terminal 150–amino acid region of PIF1. Unlike PIF3, PIF1 does not interact with the two halves of either phyA or phyB separately. Moreover, overexpression of a light-stable truncated form of PIF1 causes constitutively photomorphogenic phenotypes in the dark. Taken together, these data suggest that removal of the negative regulators (e.g., PIFs) by light-induced proteolytic degradation might be sufficient to promote photomorphogenesis.