Browsing by Author "Vadassery, Jyothilakshmi"

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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.
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.
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.
AtSWEET11 and AtSWEET12 transporters function in tandem to modulate sugar flux in plants
(John Wiley & Sons, 2023) Fatima, Urooj; Balasubramaniam, D.; Khan, Wajahat Ali; Kandpal, Manu; Vadassery, Jyothilakshmi; Arockiasamy, Arulandu; Senthil-Kumar, Muthappa
The sugar will eventually be exported transporter (SWEET) members in Arabidopsis, AtSWEET11 and AtSWEET12 are the important sucrose efflux transporters that act synergistically to perform distinct physiological roles. These two transporters are involved in apoplasmic phloem loading, seed filling, and sugar level alteration at the site of pathogen infection. Here, we performed the structural analysis of the sucrose binding pocket of AtSWEET11 and AtSWEET12 using molecular docking followed by rigorous molecular dynamics (MD) simulations. We observed that the sucrose molecule binds inside the central cavity and in the middle of the transmembrane (TM) region of AtSWEET11 and AtSWEET12, that allows the alternate access to the sucrose molecule from either side of the membrane during transport. Both AtSWEET11 and AtSWEET12, shares the similar amino acid residues that interact with sucrose molecule. Further, to achieve more insights on the role of these two transporters in other plant species, we did the phylogenetic and the in-silico analyses of AtSWEET11 and AtSWEET12 orthologs from 39 economically important plants. We reported the extensive information on the gene structure, protein domain and cis-acting regulatory elements of AtSWEET11 and AtSWEET12 orthologs from different plants. The cis-elements analysis indicates the involvement of AtSWEET11 and AtSWEET12 orthologs in plant development and also during abiotic and biotic stresses. Both in silico and in planta expression analysis indicated AtSWEET11 and AtSWEET12 are well-expressed in the Arabidopsis leaf tissues. However, the orthologs of AtSWEET11 and AtSWEET12 showed the differential expression pattern with high or no transcript expression in the leaf tissues of different plants. Overall, these results offer the new insights into the functions and regulation of AtSWEET11 and AtSWEET12 orthologs from different plant species. This might be helpful in conducting the future studies to understand the role of these two crucial transporters in Arabidopsis and other crop plants.
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, Jyothilakshmi
Cellular 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.
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, Jyothilakshmi
The 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.
Calmodulin-like protein CML37 is a positive regulator of ABA during drought stress in Arabidopsis
(Taylor & Francis Group, 2015) Scholz, Sandra S; Reichelt, Michael; Vadassery, Jyothilakshmi; Mithöfer, Axel
Plants need to adapt to various stress factors originating from the environment. Signal transduction pathways connecting the recognition of environmental cues and the initiation of appropriate downstream responses in plants often involve intracellular Ca(2+) concentration changes. These changes must be deciphered into specific cellular signals. Calmodulin-like proteins, CMLs, act as Ca(2+) sensors in plants and are known to be involved in various stress reactions. Here, we show that in Arabidopsis 2 different CMLs, AtCML37 and AtCML42 are antagonistically involved in drought stress response. Whereas a CML37 knock-out line, cml37, was highly susceptible to drought stress, CML42 knockout line, cml42, showed no obvious effect compared to wild type (WT) plants. Accordingly, the analysis of the phytohormone abscisic acid (ABA) revealed a significant reduction of ABA upon drought stress in cml37 plants, while in cml42 plants an increase of ABA was detected. Summarizing, our results show that both CML37 and CML42 are involved in drought stress response but show antagonistic effects.
Cas variants increased the dimension of the CRISPR tool kit
(John Wiley & Sons, 2024) Dixit, Sameer; Shukla, Akanchha; Pawar, Mahendra; Vadassery, Jyothilakshmi
CRISPR technology shows promising developments in multiple areas of biological sciences. It is a developing technology and continuously evolving day by day. Cas proteins, an integral component of CRISPR technology, has enormous scope for new discoveries and reengineering. It can enhance new dimensions in CRISPR tool kit. In this chapter, we systematically explain the classification of CRISPR-Cas system. We separately compiled applicability of different CRISPR-Cas system. In the end, we discussed about the advancement and reengineering of available CRISPR-Cas systems.
Channels hold the key: cyclic nucleotide gated channels (CNGC) in plant biotic stress signaling
(International Society of Endocytobiology, 2015) Meena, Mukesh K.; Vadassery, Jyothilakshmi
Cyclic nucleotide‐gated channels (CNGC) are non‐ selective cation channels opened by the direct binding of cyclic nucleotides and permit diffusion of divalent and monovalent cations, including Ca2+ and K+. The role of CNGC in various plant signaling process is emerging rapidly. Multiple studies have shown that CNGCs are involved in both basal and R gene mediated plant immunity. In this review, we will concentrate on the role of CNGCs in plant immunity, their role in calcium uptake in plants and on their relevance for plant phenotypic plasticity, focusing mostly on the well‐studied Arabidopsis CNGCs.
Chlorogenic acid-mediated chemical defense of plants against insect herbivores
(John Wiley & Sons, 2019) Kundu, Anish; Vadassery, Jyothilakshmi
Chlorogenic acid is one of the most abundant beneficial polyphenols in plants and is well known as nutritional anti‐oxidant in plant based foods. Apart from its dietary antioxidant activity, it has been proven to be an efficient defense molecule against a broad range of insect herbivores. In the last two decades, several reports have shown the effectiveness of chlorogenic acid for insect's growth deterrence. Biosynthetic pathway for chlorogenic acid biosynthesis in plants was previously elucidated and metabolic engineering of the principal pathway showed high chlorogenic acid production in tomato plants. Herbivore mediated induction of chlorogenic acid biosynthesis was also demonstrated both at metabolite and transcript level, though herbivore‐mediated molecular regulation of chlorogenic acid biosynthesis is not fully elucidated yet. In this communication, we present our views on the efficacy of chlorogenic acid as anti‐herbivore defense molecule in plants and also discuss its future outlook.
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.
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.
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.
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.
Forward genetic screen using transgenic calcium reporter aequorin to identify novel targets in calcium signaling
(Journal of Visualized Experiment, 2020) Mittal, Deepika; Mishra, Shruti; Prajapati, Ramgopal; Vadassery, Jyothilakshmi
Forward genetic screens have been important tools in the unbiased identification of genetic components involved in several biological pathways. The basis of the screen is to generate a mutant population that can be screened with a phenotype of interest. EMS (ethyl methane sulfonate) is a commonly used alkylating agent for inducing random mutation in a classical forward genetic screen to identify multiple genes involved in any given process. Cytosolic calcium (Ca2+) elevation is a key early signaling pathway that is activated upon stress perception. However the identity of receptors, channels, pumps and transporters of Ca2+ is still elusive in many study systems. Aequorin is a cellular calcium reporter protein isolated from Aequorea victoria and stably expressed in Arabidopsis. Exploiting this, we designed a forward genetic screen in which we EMS-mutagenized the aequorin transgenic. The seeds from the mutant plants were collected (M1) and screening for the phenotype of interest was carried out in the segregating (M2) population. Using a 96-well high-throughput Ca2+ measurement protocol, several novel mutants can be identified that have a varying calcium response and are measured in real time. The mutants with the phenotype of interest are rescued and propagated till a homozygous mutant plant population is obtained. This protocol provides a method for forward genetic screens in Ca2+ reporter background and identify novel Ca2+ regulated targets. The video component of this article can be found at https://www.jove.com/video/61259/
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.
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.
In silico identification of effector proteins from generalist herbivore Spodoptera litura
(BioMed Central Ltd, 2020) Prajapati, Vinod Kumar; Varma, Mahendra; Vadassery, Jyothilakshmi
Background: The common cutworm, Spodoptera litura Fabricius is a leaf and fruit feeding generalist insect of the order Lepidoptera and a destructive agriculture pest. The broad host range of the herbivore is due to its ability to downregulate plant defense across different plants. The identity of Spodoptera litura released effectors that downregulate plant defense are largely unknown. The current study aims to identify genes encoding effector proteins from salivary glands of S. litura (Fab.). Results: Head and salivary glands of Spodoptera litura were used for de-novo transcriptome analysis and effector prediction. Eight hundred ninety-nine proteins from the head and 330 from salivary gland were identified as secretory proteins. Eight hundred eight proteins from the head and 267 from salivary gland proteins were predicted to be potential effector proteins. Conclusions: This study is the first report on identification of potential effectors from Spodoptera litura salivary glands.
Invasion of fall armyworm (Spodoptera frugiperda) in India: nature, distribution, management and potential impact
(Current Science Association, Bengaluru, 2020) Suby, S.B.; Soujanya, P. Lakshmi; Yadava, Pranjal; Patil, Jagadeesh; Subaharan, K.; Prasad, G. Shyam; Babu, K. Srinivasa; Jat, S. L.; Yathish, K. R.; Vadassery, Jyothilakshmi; Kalia, Vinay K.; Bakthavatsalam, N.; Shekhar, J. C.; Rakshit, Sujay
Fall armyworm (FAW; Spodoptera frugiperda (J. E. Smith)) is emerging as the most destructive pest of maize in India since its report in May 2018. Its rapid spread to more than 90% of maize-growing areas of diverse agro-ecologies of India within a span of 16 months presents a major challenge to smallholder maize farmers, maize-based industry, as well as food and nutritional security. FAW has been reported from other crops as well like sorghum and millets with varied proportion of economic damage. In this review, the transboundary movement of FAW, role of ecology, its spread and damage are discussed. Management of FAW by developing and deploying various pest management tools is elaborated. The role of agroecological measures for reducing FAW damage with African experiences has also been highlighted.
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, Jyothilakshmi
Plants 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.