Institutional Publications

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Subject: search.filters.subject.herbivory

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    Cellular responses in the pigeonpea wild relative Cajanus platycarpus to Helicoverpa armigera herbivory: The role of methionine sulfoxide reductase B1 (CpMSRB1) in enhanced defense
    (American Phytopathological Society, 2025) Rathinam, Maniraj; Dokka, Narasimham; Senthil, Kameshwaran; Mahawar, Shivangi; Tyagi, Shaily; Rengarajan, Dineshkumar; Vijayaraghavareddy, Preethi; Iyyappan, Yuvaraj; YB, Basavaraj; Reddy, Sandeep; T, Vinutha; G, Rama Prashat; Sinha, Subodh Kumar; Dash, Prasanta K.; Sreeman, Sheshshayee; Majee, Manoj; Sreevathsa, Rohini
    Understanding key cellular mechanisms leading to improved defense against various stressors is essential for cultivating robust nutritious crops capable of flourishing in diverse environments. We present an in-depth characterization of the defense response in the pigeonpea wild relative Cajanus platycarpus to herbivory by pod borer Helicoverpa armigera. To fight the attacking pest, C. platycarpus strategically activated non-enzymatic reactive oxygen species (ROS) scavengers and unleashed methionine sulfoxide reductases to safeguard the integrity of methionine residues. We unveiled for the first time physical interaction between CpMSRB1 and chorismate mutase (CpCM1.1), a pivotal player in the phenylpropanoid pathway. This association fueled the synthesis of phenylpropanoids and enhanced ROS scavenging crucial for repelling herbivores. Repairing CpCM1.1 also boosted salicylic acid production, coordinating defense signaling with jasmonic acid. Additionally, heterologous expression of CpMSRB1 in tomato improved defense against herbivory by enhanced ROS scavenging and polyphenol production. This study demonstrates the role of CpMSRB1 in protecting a major enzyme in the shikimate pathway, reinforcing defense against H. armigera.
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    Whispering through the leaves: elucidating the mechanical perception and downstream defence response against herbivory
    (John Wiley & Sons, 2026) Vero, Khrade; Meena, Mukesh Kumar
    Insect herbivory generates not only tissue loss but also a suite of biophysical and chemical cues that plants must detect and interpret. To cope with these challenges, plants have evolved specialised structures and molecular mechanisms that perceive mechanical inputs and translate them into coordinated defence responses. This review summarises the concept of mechanostimulation during insect feeding, with a focus on how plants recognise mechanical cues and integrate them into broader defence signalling networks. We outline the types of stimuli generated during herbivory, the morphological and molecular sensors involved in mechanoperception, and the electrical signalling processes that mediate intra- and inter-cellular communication of long-distance signal transmission, for which the vascular system, particularly the phloem and xylem, emerges as a critical conduit. We further discuss how mechanostimulation interfaces with hormonal pathways and transcriptional regulation, ultimately activating defence genes. This framework is further extended to non-vascular plants such as bryophytes, where mechanosensing and defence occur in the absence of vascular tissues, shedding light on how these strategies originated and evolved in early land plants. Collectively, these insights provide a comprehensive framework for understanding how mechanostimulation shapes plant defence and offers avenues for future research in enhancing crop resilience.
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    Deep metabolomics revealed trajectories of jasmonate signaling-mediated primary metabolism in Arabidopsis upon Spodoptera litura herbivory
    (John Wiley & Sons, 2025) Kundu, Anish; Bera, Paramita; Mishra, Shruti; Vadassery, Jyothilakshmi
    Plants defend against chewing herbivores by up-regulating jasmonic acid (JA) signaling, which activates downstream signaling cascades and produces numerous secondary metabolites that act as defense molecules against the herbivores. Although secondary metabolism always remains a focus of research, primary metabolism is also reported to be realigned upon herbivory. However, JA signaling-mediated modulation of primary metabolites and their metabolic pathways in plants are mostly unexplored. Here, we applied gas chromatography–mass spectrometry-based untargeted metabolomics aided with computational statistical frameworks on wild type Arabidopsis, mutants of active JA receptor (i.e., CORONATINE-INSENSITIVE 1, COI1-1) and downstream transcription factor (i.e., MYC2) to navigate the JA signaling-mediated primary metabolism alterations during herbivory. Pathway and metabolite's chemical class enrichment analysis revealed JA signaling is crucial for constitutive as well as herbivore-induced primary metabolism and topology of their interaction networks. JA signaling majorly modulated alterations of sugars, amino acids and related metabolites. Herbivory-mediated sugar depletion and induction of methionine for aliphatic glucosinolates are also dependent on JA signaling. Taken together, our results demonstrate trails of JA signaling-mediated primary metabolic alterations associated with herbivory.
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    External jasmonic acid isoleucine mediates amplification of plant elicitor peptide receptor (PEPR) and jasmonate-based immune signalling
    (John Wiley & Sons, 2024) Mittal, Deepika; Gautam, Janesh Kumar; Varma, Mahendra; Laie, Amrutha; Mishra, Shruti; Behera, Smrutisanjita; Vadassery, Jyothilakshmi
    Jasmonic acid-isoleucine (JA-Ile) is a plant defence hormone whose cellular levels are elevated upon herbivory and regulate defence signalling. Despite their pivotal role, our understanding of the rapid cellular perception of bioactive JA-Ile is limited. This study identifies cell type-specific JA-Ile-induced Ca2+ signal and its role in self-amplification and plant elicitor peptide receptor (PEPR)-mediated signalling. Using the Ca2+ reporter, R-GECO1 in Arabidopsis, we have characterized a monophasic and sustained JA-Ile-dependent Ca2+ signature in leaf epidermal cells. The rapid Ca2+ signal is independent of positive feedback by the JA-Ile receptor, COI1 and the transporter, JAT1. Microarray analysis identified up-regulation of receptors, PEPR1 and PEPR2 upon JA-Ile treatment. The pepr1 pepr2 double mutant in R-GECO1 background exhibits impaired external JA-Ile induced Ca2+cyt elevation and impacts the canonical JA-Ile responsive genes. JA responsive transcription factor, MYC2 binds to the G-Box motif of PEPR1 and PEPR2 promoter and activates their expression upon JA-Ile treatment and in myc2 mutant, this is reduced. External JA-Ile amplifies AtPep-PEPR pathway by increasing the AtPep precursor, PROPEP expression. Our work shows a previously unknown non-canonical PEPR-JA-Ile-Ca2+-MYC2 signalling module through which plants sense JA-Ile rapidly to amplify both AtPep-PEPR and jasmonate signalling in undamaged cells.
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    A comprehensive investigation of lipid-transfer proteins from Cicer arietinum disentangles their role in plant defense against Helicoverpa armigera-infestation
    (Frontiers Media S.A., 2023) Saxena, Harshita; Negi, Harshita; Keshan, Radhika; Chitkara, Pragya; Kumar, Shailesh; Chakraborty, Amrita; Roy, Amit; Singh, Indrakant K.; Singh, Archana
    Lipid Transfer Proteins (LTPs) play a crucial role in synthesizing lipid barrier polymers and are involved in defense signaling during pest and pathogen attacks. Although LTPs are conserved with multifaceted roles in plants, these are not yet identified and characterized in Cicer arietinum. In this study, a genome-wide analysis of LTPs was executed and their physiochemical properties, biochemical function, gene structure analysis, chromosomal localization, promoter analysis, gene duplication, and evolutionary analysis were performed using in silico tools. Furthermore, tissue-specific expression analysis and gene expression analysis during pest attack was also conducted for the LTPs. A total of 48 LTPs were identified and named as CaLTPs. They were predicted to be small unstable proteins with "Glycolipid transfer protein" and "Alpha-Amylase Inhibitors, Lipid Transfer and Seed Storage" domains, that are translocated to the extracellular region. CaLTPs were predicted to possess 3-4 introns and were located on all the eight chromosomes of chickpea with half of the CaLTPs being localized on chromosomes 4, 5, and 6, and found to be closely related to LTPs of Arabidopsis thaliana and Medicago trancatula. Gene duplication and synteny analysis revealed that most of the CaLTPs have evolved due to tandem or segmental gene duplication and were subjected to purifying selection during evolution. The promoters of CaLTPs had development-related, phytohormone-responsive, and abiotic and biotic stress-related cis-acting elements. A few CaLTP transcripts exhibited differential expression in diverse tissue types, while others showed no/very low expression. Out of 20 jasmonate-regulated CaLTPs, 14 exhibited differential expression patterns during Helicoverpa armigera-infestation, indicating their role in plant defense response. This study identified and characterized CaLTPs from an important legume, C. arietinum, and indicated their involvement in plant defense against H. armigera-infestation, which can be further utilized to explore lipid signaling during plant-pest interaction and pest management.
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    Systemic cytosolic Ca2+ elevation is activated upon wounding and herbivory in Arabidopsis
    (John Wiley & Sons, 2015) Kiep, Victoria; Vadassery, Jyothilakshmi; Lattke, Justus; Maaß, Jan-Peter; Boland, Wilhelm; Peiter, Edgar; Mithöfer, Axel
    Calcium ion (Ca2+) signalling triggered by insect herbivory is an intricate network with multiple components, involving positive and negative regulators. Real-time, noninvasive imaging of entire Arabidopsis thaliana rosettes was employed to monitor cytosolic free calcium ([Ca2+]cyt) elevations in local and systemic leaves in response to wounding and Spodoptera littoralis feeding. Luminescence emitted by the cytosol-localized Ca2+ reporter aequorin was imaged using a high-resolution photon-counting camera system. Spodoptera littoralis feeding on Arabidopsis induced both local and systemic [Ca2+]cyt elevations. Systemic [Ca2+]cyt signals were found predominantly in adjacent leaves with direct vascular connections to the treated leaf and appeared with a delay of 1 to 2 min. Simulated herbivory by wounding always induced a local [Ca2+]cyt response, but a systemic one only when the midrib was wounded. This systemic [Ca2+]cyt response was suppressed by the presence of insect-derived oral secretions as well as in a mutant of the vacuolar cation channel, Two Pore Channel 1 (TPC1). Our results provide evidence that in Arabidopsis insect herbivory induces both local and systemic [Ca2+]cyt signals that distribute within the vascular system. The systemic [Ca2+]cyt signal could play an important signalling role in systemic plant defence.