Institutional Publications
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Item Whispering through the leaves: elucidating the mechanical perception and downstream defence response against herbivory(John Wiley & Sons, 2026) Vero, Khrade; Meena, Mukesh KumarInsect 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.Item Quantification of jasmonic acid and salicylic acid in plant-insect interactions(Springer Nature Publishing AG, 2026) Meena, Mukesh KumarPlants encounter a variety of insect herbivores and have developed complex defense mechanisms against different feeding strategies. Phytohormones jasmonic acid (JA) and salicylic acid (SA) play a central role in recognizing and mounting appropriate defense response against pathogens. Primarily, JA provides resistance against chewing insect herbivores, whereas SA bolster defense against biotrophs and phloem-feeding insects (aphids and whitefly). Complex interaction of JA and SA signaling creates a plant stress memory which helps to generate elevated defense response to future insect threats. Phytohormone quantification can provide significant insights about activated plant defense response and involved signaling pathways. Here, we describe a detailed and reproducible protocol for phytohormone quantification (SA, ABA, JA, and JA-Ile) in insect-fed Arabidopsis leaves tissues. JA and JA-Ile quantification results clearly indicate their contribution in plant adaptation and defense response.Item Insect herbivory simulation and insect bioassays to study plant stress memory response(Springer Nature Publishing AG, 2026) Meena, Mukesh KumarPlant stress memory response is an emerging field in plant–insect interaction. Recent reports indicate phytohormone jasmonic acid (JA) triggers long-term effects on the defense phenotype, transcriptome, and DNA methylome of Arabidopsis. Long-term JA-mediated induced resistance required MYC2/3/4 transcription factors and epigenetic regulatory components that prepare plants for future insect herbivore threats. Three weeks after transient JA signaling, 5-week-old plants retained induced resistance against herbivory but showed increased susceptibility to pathogens. This mechanism is linked with long-term priming and/or upregulation of JA-dependent defense genes but repression of ethylene- and salicylic acid-dependent genes. Still more research is required to fully understand plant stress memory response in plant–insect interaction. Here, a detailed and reproducible protocol for simulated herbivory and sample collection for transcriptomic and metabolomic studies is described to investigate involved defense signaling pathways. Furthermore, the insect bioassay protocol is described to study insect performance on various plant genotypes. Both protocols are robust and could be useful to study plant stress memory response in plant defense mechanisms through simulated herbivory and direct insect performance and feeding behavior by insect bioassays.Item The Arabidopsis eATP receptor DORN1 and CNGC19 calcium channel act in tandem to regulate plant defense upon Spodoptera litura herbivory(Oxford University Press, 2025) Kundu, Pritha; Kumari, Misha; Meena, Mukesh Kumar; Mishra, Shruti; Vadassery, JyothilakshmiPlants deploy cellular Ca2+ elevation as a signal for environmental stress signaling. Extracellular ATP (eATP) is released into the extracellular matrix when cells are wounded. DOES NOT RESPOND TO NUCLEOTIDES 1 (DORN1), a key legume-type lectin receptor, senses and binds eATP and activates Ca2+ signaling. No evidence directly links calcium-mediated eATP signaling to resistance against insect herbivores. Here, we report upregulation of DORN1 transcripts upon wounding and Spodoptera litura feeding in Arabidopsis. Loss-of-function of DORN1 resulted in increased S. litura feeding compared to that on wildtype. Plant immunity is compromised in dorn1 mutants as they show reduced S. litura oral secretion mediated Ca2+ elevation, jasmonic acid accumulation, and expression of jasmonate responsive genes. The herbivory-induced calcium channel, CYCLIC NUCLEOTIDE GATED CHANNEL 19 (CNGC19), co-expresses with DORN1. We found that eATP-induced Ca2+ elevation requires functional CNGC19. Loss-of-function of DORN1 and CNGC19 highly increased the susceptibility to S. litura, mediated by reduced accumulation of jasmonates. We also demonstrate a plausible interaction of CNGC19 with DORN1. The data implicate the role of damage-released eATP and its receptor DORN1 in herbivory-induced defense signaling. DORN1 together with the Ca2+ channel CNGC19 generate the eATP-induced Ca2+ elevation, leading to the activation of immune signaling.Item Regulating postharvest pathogen infection and decay using biotechnological tools(Taylor & Francis Group, 2024) Meena, Mukesh KumarRegulating postharvest pathogen infection and decay using biotechnological tools explores the critical issues surrounding postharvest losses in fruits and vegetables caused by pathogens and their management. Despite the pivotal role of plants in sustaining life on Earth, they face continuous challenges from environmental stresses, including biotic factors like bacteria, fungi, and insect pests, which lead to preharvest and postharvest crop losses. With the global population expected to reach 10 billion by 2050, there is a pressing need to address these losses, estimated at 30%–50% or more, to meet increasing food demands. This chapter delves into the causes of postharvest diseases, including latent infections and infections initiated during and after harvest, highlighting the importance of pathogen detection and identification. Additionally, economic and social challenges posed by postharvest factors, such as environmental pollution from pesticide usage and health risks associated with pesticide residues, are discussed. Conventional methods like chemical treatments are commonly employed for disease control, but their adverse effects necessitate the exploration of alternative strategies. The chapter then explores 136novel biotechnological approaches, including genetic engineering, RNA interference, and genome editing, as promising solutions to mitigate postharvest losses sustainably. While challenges in the commercialization of biotechnological approaches exist, the precision and potential of CRISPRCas-based genome editing offer promising avenues for future research and crop improvement to ensure global food security.Item Negative regulators of grain yield and mineral contents in rice: potential targets for CRISPR-Cas9-mediated genome editing(Springer Nature Publishing AG, 2023) Yadav, Banita; Majhi, Ashis; Phagna, Kanika; Meena, Mukesh Kumar; Ram, HasthiRice is a major global staple food crop, and improving its grain yield and nutritional quality has been a major thrust research area since last decades. Yield and nutritional quality are complex traits which are controlled by multiple signaling pathways. Sincere efforts during past decades of research have identified several key genetic and molecular regulators that governed these complex traits. The advent of clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9)-mediated gene knockout approaches has accelerated the development of improved varieties; however, finding out target gene with negative regulatory function in particular trait without giving any pleiotropic effect remains a challenge. Here, we have reviewed past and recent literature and identified important negative regulators of grain yield and mineral contents which could be potential targets for CRISPR-Cas9-mediated gene knockout. Additionally, we have also compiled a list of microRNAs (miRNAs), which target positive regulators of grain yield, plant stress tolerance, and grain mineral contents. Knocking out these miRNAs could help to increase expression of such positive regulators and thus improve the plant trait. The knowledge presented in this review would help to further accelerate the CRISPR-Cas9-mediated trait improvement in rice.Item Jasmonic acid (JA) induced-calcium elevation in Arabidopsis is highly variable due to time of day and conversion to JA-Ile(Springer Nature Publishing AG, 2020) Prajapati, Ramgopal; Mittal, Deepika; Meena, Mukesh Kumar; Vadassery, JyothilakshmiPlants have evolved mechanisms to effectively anticipate environmental changes via diurnal rhythmicity (day/night) maintained by the circadian clock. Jasmonic acid biosynthesis and signalling are known to be under the control of the circadian clock. Both JA and its bioactive form jasmonoyl-L-isoleucine (JA-Ile) when externally added can induce a cytosolic Ca2? influx in Arabidopsis thaliana. JA and JA-Ile induced Ca2? is poorly understood and often used interchangeably to study Ca2? regulation of jasmonates. We attempted to understand if they are similar and if diurnal rhythms or time of day regulate them. JA induced Cacyt 2? signature is variable according to time-of-day in Arabidopsis. JA is sensed in two ways according to the time-of-day (a) directly sensed as JA and induces Cacyt 2? elevation (b) JA gets converted into the JA-Ile by JAR1 and is sensed as JA-Ile, which we proved using jar1-1*aequorin. This twin sensing mode is responsible for variability in JA induced Cacyt 2? signature. We further suggest caution when using JA as a stimulant for Cacyt 2? elevation measurements to compare wild-type (Col-0 transformed with pMAQ2; transgenic aequorin) and effect of different mutations. On the other hand bioactive JA-Ile induced Cacyt 2? signature is constant diurnally with maximum amplitude at dawn which coincides with maximum sensitivity of JA-Ile receptor, COI1 and increased VSP2 expression. From the above study we conclude that JA-Ile induced Cacyt 2? elevation is a better read-out than the highly variable JA-induced Cacyt 2? elevations to study the output pathways.Item Calcium channel CNGC19 mediates basal defense signaling to regulate colonization of Piriformospora indica in Arabidopsis roots(Oxford University Press, 2020) Jogawat, Abhimanyu; Meena, Mukesh Kumar; Kundu, Anish; Varma, Mahendra; Vadassery, JyothilakshmiThe activation of calcium signaling is a crucial event for perceiving environmental stress. Colonization by Piriformospora indica, a growth promoting root endosymbiont activates cytosolic Ca2+ in Arabidopsis roots. In this study, we analyze the role of calcium channels responsible for Ca2+ fluxes and its functional relevance. Expression profiling revealed that CNGC19 is a early activated gene, induced by unidentified components in P. indica cell wall extract. Functional analysis revealed that loss-of-function of CNGC19 results in growth inhibition by P.indica, due to increased colonization and loss of controlled P. indica growth. P. indica cell wall extract induced cytosolic Ca2+ elevation is reduced in cngc19 mutant indicating a role in generation of Ca2+cyt elevation. MAMP-trigerred immunity (MTI) is compromised in cngc19 lines as evident from unaltered callose deposition, reduced cis-OPDA, JA and JA-Ile levels and downregulation of jasmonate and other defense related genes which contributes to shift towards pathogenic response. Loss-of-function of CNGC19 results in inability to modulate indole glucosinolate content during P. indica-colonization. CNGC19 mediated basal immunity is AtPep receptor, PEPR dependent. CNGC19 is also crucial for P. indica mediated suppression of AtPep induced immunity. Thus, Arabidopsis CNGC19 is an important Ca2+ channel, maintaining a robust innate immunity and crucial for growth promotion signalling upon P. indica colonization.Item The Ca2+ channel CNGC19 regulates Arabidopsis defense against spodoptera herbivory(American Society of Plant Biologists, 2019) Meena, Mukesh Kumar; Prajapati, Ramgopal; Krishna, Deepthi; Divakaran, Keerthi; Pandey, Yogesh; Reichelt, Michael; Mathew, M.K.; Boland, Wilhelm; Mithöfer, Axel; Vadassery, JyothilakshmiCellular calcium elevation is an important signal used by plants for recognition and signaling of environmental stress. Perception of the generalist insect, Spodoptera litura, by Arabidopsis thaliana activates cytosolic Ca2+ elevation, which triggers downstream defense. However, not all the Ca2+ channels generating the signal have been identified, nor are their modes of action known. We report on a rapidly activated, leaf vasculature- and plasma membrane-localized, CYCLIC NUCLEOTIDE GATED CHANNEL19 (CNGC19), which activates herbivory-induced Ca2+ flux and plant defense. Loss of CNGC19 function results in decreased herbivory defense. The cngc19 mutant shows aberrant and attenuated intra-vascular Ca2+ fluxes. CNGC19 is a Ca2+ permeable channel, as hyperpolarization of CNGC19-expressing Xenopus oocytes in the presence of both cAMP and Ca2+ results in Ca2+ influx. Breakdown of Ca2+-based defence in cngc19 mutants leads to a decrease in herbivory-induced JA-Ile biosynthesis and expression of JA responsive genes. cngc19 mutants are deficient in aliphatic glucosinolate accumulation and hyperaccumulate its precursor, methionine. CNGC19 modulates aliphatic glucosinolate biosynthesis in tandem with BRANCHED-CHAIN AMINO ACID TRANSAMINASE4 (BCAT4), which is involved in the chain elongation pathway of Met-derived glucosinolates. Furthermore, CNGC19 interacts with herbivory-induced CALMODULIN2 (CaM2) in planta. Together, our work reveals a key mechanistic role for the Ca2+ channel CNGC19 in the recognition of herbivory and the activation of defense signaling.Item Decoding and relay of calcium signals by CBL-CIPK module in plants(Indian National Science Academy, 2019) Meena, Mukesh Kumar; Sardar, Atish; Chattopadhyay, DebasisCalcium is an essential macronutrient and a second messenger for signal transduction in plants. Apart from acting as a second messenger, calcium is also required for cytoskeleton, cell division, pollen tube growth and as a co-factor. Cytoplasmic calcium ion ([Ca2+](cyt)) is maintained at a low level, however, is rapidly elevated using storages in organelles on perception of a stimulus. Ca2+-binding proteins that sense the kinetics and magnitude of elevated [Ca2+](cyt) convert the chemical signals to biological signals and define specificity of responses. These proteins are broadly classified into sensor relays and sensor responders. Sensor relay proteins require another interacting protein to transmit the signal; whereas, the sensor responders combine within one protein the relay, amplification and response functions. A significant achievement has been made in the last three decades that identified and characterized various proteins instrumental in decoding Ca2+-signals in plant cells. The latest addition in Ca2+-signaling is Calcineurin B-like proteins (CBLs) and their interacting kinases (CIPKs). It is believed that flexibility of interactions between different CBL and CIPK proteins and their sub-cellular localizations are crucial in sensing and responding to specific signals. In this review, we have laid emphasis on the recent and emerging advancements in understanding of the CBL-CIPK module.