Publications of NIPGR Scientists

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Author: search.filters.author.Vadassery, JyothilakshmiStart date: 2020

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    Evolutionary trade-offs in plant immunity: prioritizing antiviral priming by herbivore-induced plant volatiles over defense against herbivores
    (Springer Nature Publishing AG, 2026) Megaladevi, Pachamuthu; Vadassery, Jyothilakshmi
    Plants respond to insect herbivory by producing and releasing distinctive blends of volatile compounds. These herbivore-induced plant volatiles (HIPVs) serve several roles, including direct defense through toxic or repellent effects on herbivores and indirect defense by attracting the herbivores’ natural enemies (Bleeker et al. 2009; Veyrat et al. 2016). HIPVs also act as warning signals, informing undamaged tissues within the same plant and nearby plants of a pending insect attack (Heil and Bueno 2007). HIPVs are mostly composed of terpenes, fatty acid-derived compounds, and shikimic acid pathway metabolites. In response to certain HIPVs, neighboring plants enter a primed state, preparing for a future attack. As a result, when these primed plants are later attacked by the same herbivore, they can mount a faster and stronger defense response (Arimura et al. 2009). However, many specialized herbivores and pathogens can overcome, and often manipulate, these defenses to thrive on their specific host plants. Some insect vectors have evolved mutualisms with their viruses, e.g., some begomoviruses suppress terpenoid emissions that negatively affect their whitefly vectors (Bleeker et al. 2009). HIPV emissions vulnerable to manipulation include the generalist whitefly Bemisia tabaci-induced volatile blend (composed of the monoterpenes β-myrcene and ρ-cymene, and the sesquiterpene β-caryophyllene). These whitefly-induced volatiles prime salicylic acid-dependent defenses against pathogens in tomato plants while suppressing jasmonic acid-dependent defenses against herbivores, thus rendering neighboring tomato plants more susceptible to whiteflies (Zhang et al. 2019). This appears to be paradoxical and warrants further investigation.
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    Developing together: The elementome and biogeochemical niche of the mutualistic occupants of a fig microcosm
    (2026) Kulkarni, Manasa; Naik, Nehal Vijay; Vadassery, Jyothilakshmi; Borges, Renee M.
    In brood-site pollination mutualisms, where flowers provide nutrition and shelter to pollinator offspring in exchange for pollination, resource allocation to inflorescences is directly related to plant and pollinator fitness. We determine resource allocation to components of an enclosed monoecious Ficus inflorescence or syconium that, besides seeds, also houses and provides nutrition to pollinator wasp offspring, each developing within individual uniovulate galled flowers. Besides biomass, we determine elemental concentrations as parameters of resource allocation. For the first time, we apply the biogeochemical niche (BN) concept to a mutualism and construct the BN of syconial occupants using the elementomes and stoichiometric ratios of plant, seed and pollinator tissue. We predicted that BNs of seeds and galls containing wasps should differ due to differences in tissue type, facilitating their co-development. We also measure trophic stoichiometric ratios (TSRs) for various elements to determine resource mismatch between consumers and resources. We found that the syconium wall, which insulates and protects developing seeds and wasps, constituted 58% of syconial biomass. Individual pollinators and their galls were significantly heavier than seeds indicating that their development is resource-intensive. As predicted, seeds and adult female pollinators had significantly different BNs, highlighting differences in nutritional needs of these mutualistic occupants within a shared nutrient-providing resource. Pollinators had significantly lower C:N and C:P ratios than the syconial wall indicating limitation of N and P within host resources. The BN of pollinator wasps was distinguished by significantly higher concentrations of nitrogen, phosphorus, zinc and sulphur compared to the syconium wall or seeds. TSRs of >4 for nitrogen and sulphur highlight the heightened resource mismatch that pollinators likely face for these elements during their development. We found no overlap in the BNs of male and female pollinator wasps, likely due to their starkly different anatomical and functional traits. Overall, our study demonstrates how BNs and TSRs can reveal trading of resources within mutualisms highlighting non-overlapping requirements for elements and the potential limitations they can pose for resource providers and consumers. These parameters can serve as common currencies for comparisons across mutualistic interactions.
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    Arabidopsis SWEET12 contributes to the regulation of sugar allocation and defense responses during interaction with Serendipita indica
    (Oxford University Press, 2026) Jogawat, Abhimanyu; Sanyasi, Madhan; Menon, Sidhardh H; Goyal, Divya; Nair, Athira Mohandas; Vadassery, Jyothilakshmi
    Carbon availability is a central determinant of beneficial plant–fungal associations, and sugar transporters are key levers of this exchange. SWEETs (SUGARS WILL EVENTUALLY BE EXPORTED TRANSPORTER) are involved in transporting various kinds of sugars in plants; however, their functional roles in fungal symbiosis are not sufficiently explored. In this study, we investigate the functional relevance of Arabidopsis SWEETs in the interaction with endophytic fungi, Serendipita indica. Transcript profiling of SWEET genes in response to S. indica and its major elicitor, cellotriose, revealed early root-specific induction of SWEET12. Using a SWEET12 loss-of-function mutant, we demonstrate that the absence of SWEET12 disrupts the major outcomes of mutualism including growth promotion, balanced colonization, sugar allocation, and the accumulation of defense phytohormones (JA and SA). Transcriptome profiling further reveals that SWEET12 buffers whole-plant responses by coordinating genes linked to carbohydrate, nitrogen, and lipid metabolism, and by tuning defense signalling and nutrient transporter networks. Our findings indicate that SWEET12 is essential for balancing fungal colonization and host defense, thereby promoting plant growth. SWEET12 does so by acting as sugar valve that meters sugar release to the apoplast, enabling the fungus to access carbon while preserving host sugar homeostasis and immune competence.
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    Anaerobic-aerobic swerve in arsenic-stressed deepwater rice genotype under submergence
    (John Wiley & Sons, 2025) Khan, Asna; Khatoon, Narjis Saba; Vadassery, Jyothilakshmi; Gupta, Meetu
    Global floods in arsenic (As)-stressed paddy fields affect rice productivity. Future predictions of flood-related disasters provoke an urge to opt for climate-smart varieties for a secure supply. Thus, this study is designed to present the mechanisms favoring a traditional variety Mini mansoori (M.M) to withstand the dual stress of As and submergence (Sub). The investigation involved the identification of the key attributes regulating the physio-biochemical shifts in 3- and 7-day (d) submerged plants. Our results indicated that at 3 days, gas-film (GF) decrement correlated with reduced photosynthesis and Kreb-cycle enzymes. This, in turn, stimulated anaerobic enzymes, salicylic acid, and gibberellic acid (SA-GA) production, which increased glutamate metabolism through GDH enzyme, ultimately enhancing GABA and proline production to cover the energy gap. Proline dehydrogenase enzyme at 3 days monitored the stabilized proline turnover by catabolizing proline into glutamate while releasing reducing equivalents for additional ATP generation. However, at 7 days, further enhancement in GA content led to shoot elongation. The expanded GF and new leaf emergence recovered the photosynthetic machinery, TCA functioning, sugar reserves, and GABA content via proline homeostasis. This proline metabolic balance accentuated As tolerance and Sub resistance, henceforth presenting M.M. var. as climate smart for future crop improvements.
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    Nutrient use efficiency promoted hormonal crosstalk and stomatal dynamics in wheat under the co-impact of arsenic and drought
    (Elsevier B.V., 2025) Khatoon, Narjis Saba; Khan, Asna; Bhatia, Priyanka; Vadassery, Jyothilakshmi; Gupta, Meetu
    This study presents the interlink of Nutrient use efficiency (NUE) influenced hormone and stomatal dynamics, in enhancing photosynthesis under the co-impact of drought (D) and arsenic (As) in wheat. We analyzed how nitrogen (N) and phosphorus (P) supplementation under D+As modulates these interactions with jasmonic acid (JA) and sucrose, as central regulators. Enhanced JA by NP-enrichment reduced abscisic-acid (ABA) and salicylic-acid (SA) production to promote stomatal opening via sugar-transporter-proteins; TaSTP12, TaSTP51, and TaKAT-like1. Computational docking confirms strong interaction between JA, TaMYB84 and TaSTP’s (TaSTP12, TaSTP51) suggesting a functional complex that facilitates sucrose osmoregulation. This influences stomatal opening which promotes gas-exchange for better photosynthesis. Additionally, we highlight the correlation between stomatal dynamics and NP-use efficiency. The NP-promoted photosynthesis, phosphorus-use efficiency (PnPUE), and TaPHT1. 10 ensures Pi availability for Krebs-cycle. This improves non-photochemical quenching (NPQ), for ATP production, boosting CO2 assimilation. Moreover, the increased photosynthetic-nitrogen-use efficiency (PnNUE), along with TaNRT2.1, and TaAMT1.1 augmented rubisco activity, thereby increasing photosynthesis. NP-supplementation also boosts ASC-GSH cycle, which safeguards the rubisco enzyme and light-harvesting-complex. These processes optimize photosynthesis to maintain starch reserves and sustain wheat productivity under D+As. Our findings provide valuable insights into NP-mediated photosynthetic regulation and underscore the crucial role of NUE in optimizing this process.
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    Potential regulation of cleistogamy in pigeonpea through jasmonic acid and bHLH transcription factor interactions
    (Springer Nature Publishing AG, 2025) Gupta, Palak; Srivastava, Harsha; Kumar, Kuldeep; Nirgude, Machindra; Arpita, Kumari; Vadassery, Jyothilakshmi; Sharma, Sandhya; Abdin, Malik Zainul; Gaikwad, Kishor
    This study provides insights into the molecular and hormonal control of cleistogamy in pigeonpea, focusing on bHLH transcription factors and jasmonic acid pathway. Pigeonpea, an annual diploid (2n = 22) grain legume, holds significant nutritional value in cereal-dominated diets. The chasmogamous flowers of pigeonpea have a typical 9 + 1 diadelphous stamen where flowers open pre-fertilization resulting in cross-pollination. In contrast, a cleistogamous genotype characterized by polyadelphous stamens and flowers that open post-fertilization ensuring seed purity was analyzed for identifying causal pathways. Subsequent analysis focused on a set of transcription factors and their interaction with the hormonal networks associated with cleistogamy. Genes of the Jasmonic acid (JA) signaling pathway have been established to play a significant role in inducing cleistogamy and one of the key regulators of the JA pathway is bHLH (basic helix loop helix). A genome-wide survey identified 176 bHLH genes in the pigeonpea genome. Phylogenetic analysis classified 176 bHLH genes into 21 subfamilies distributed randomly across the genome. Gene ontology, cis-motifs analysis in the upstream region, and protein-protein interaction network implied the involvement of these genes in various biological processes. Expression analysis of key genes of the jasmonic acid pathway which includes MYC2 (Cc_bHLH135) along with its interacting partners TIFY/JAZ in chasmogamous and cleistogamous floral tissues revealed their potential role in flower opening. The results of UHPLC-MS/MS quantitation of Jasmonic acid and its bioactive form JA-Ile align with the expression analysis. The congruence of gene expression and hormone profiling highlights the involvement of the JA pathway in regulating flower opening, implying their potential role in cleistogamy in pigeonpea.
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    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, Jyothilakshmi
    Plants 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.
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    Host manipulations within mutualisms: Role of plant hormones in selective resource allocation
    (Springer Nature Publishing AG, 2025) Kulkarni, Manasa; Vadassery, Jyothilakshmi; Borges, Renee M.
    In some mutualisms involving host plants, photoassimilates are provided as rewards to symbionts. Endophagous organisms often manipulate host plants to increase access to photoassimilates. Host manipulations by endophagous organisms that are also mutualists are poorly understood. We show host plant manipulations by symbionts and the role of phytohormones, i.e. the auxin indole-3-acetic acid (IAA), and the cytokinin trans-zeatin (tZ), in the brood-site pollination mutualism between fig trees and pollinator fig wasps. In this interaction, pollinator wasps pollinate Ficus flowers within an enclosed inflorescence called a syconium, in exchange for flowers that develop into galls nourishing pollinator offspring. To examine host manipulation by pollinator galls by affecting host fitness through seed reduction, we compared growth hormones released by syconial occupants within three experimentally produced treatment groups of syconia: S (containing only seeds), G (containing only pollinator galls) and SG (containing seeds and pollinator galls). We harvested syconia from each treatment in early and mid-phases of syconial maturation when maximal growth occurs and measured hormone levels. Hormones were reduced by mid-phase in general; however, their levels were mostly sustained in G syconia in the mid-phase, suggesting that galls manipulate the host to continuously access resources. We found no difference in IAA and tZ levels of S and G syconia. IAA concentrations were higher in SG syconia. From the perspective of the maintenance of mutualism, syconium volume and hormone concentrations were highest when both seeds and galls were present (SG treatment), indicating that both partners control allocation of resources to syconia.
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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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    Identification of novel target genes for RNAi mediated management of the pest, Fall Armyworm (Spodoptera frugiperda, J. E. Smith)
    (Elsevier B.V., 2025) Bera, Paramita; Suby, S.B.; Dixit, Sameer; Vijayan, Vishakh; Kumar, Naveen; Sekhar, J.C.; Vadassery, Jyothilakshmi
    RNA interference (RNAi) of vital insect genes is a potential tool for targeted pest management. However, the selection of the right target genes and its dsRNA delivery method is also a challenge because the RNAi efficacy is known to vary among insect species. Fall Armyworm (FAW; Spodoptera frugiperda) is a polyphagous generalist insect pest that can feed on more than 100 plant species, with a strong preference for maize. In the present study, we evaluated the RNAi efficiency of three vital genes coding for Coatomer Subunit alpha (COPIα), Coatomer Subunit beta (COPIβ) and Glutathione-S-transferase U1 (GSTU1) as potential targets for managing FAW. Real-time PCR analysis showed that the target genes' expression level reduced to 75–80% in FAW larvae, after their continuous oral delivery through diet for 8 days. It also caused significant mortality in larvae (40–50%) and pupae (40–62%), and resulted in deformed intermediates (28–38%) and adults (25–40%). It also affected reproduction as evidenced by an approximately 50% reduction in oviposition. Moreover, exogenous application of dsRNA in maize leaves resulted in significant feeding deterrence by FAW larvae, which enhanced the frequency of cannibalism. The impact of target genes’ dsRNA on the biology and behaviour of FAW suggests their insecticidal potential. Thus, the current study reveals the novel target genes and their utility in RNA based pesticides for sustainable management of FAW.