Browsing by Author "Kundu, Anish"

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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.
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.
Molecular mechanisms of Piriformospora indica mediated growth promotion in plants
(Taylor & Francis Group, 2022) Kundu, Anish; Vadassery, Jyothilakshmi
Piriformospora indica is a root endophyte having a vast host range in plants. Plant growth promotion is a hallmark of the symbiotic interaction of P. indica with its hosts. As a plant growth-promoting microorganism, it is important to know the mechanisms involved in growth induction. Hitherto, multiple reports have demonstrated various molecular mechanisms of P. indica-mediated growth promotion, including protein kinase-mediated pathway, enhanced nutrient uptake and polyamine-mediated growth phytohormone elevation. Here, we briefly present a discussion on the state-of-the-art molecular mechanisms of P. indica-mediated growth promotion in host plants, in order to obtain a future prospect on utilization of this microorganism for sustainable agriculture.
Piriformospora indica recruits host-derived putrescine for growth promotion in plants
(Oxford University Press, 2022) Kundu, Anish; Mishra, Shruti; Kundu, Pritha; Jogawat, Abhimanyu; Vadassery, Jyothilakshmi
Growth promotion induced by the endosymbiont Piriformospora indica has been observed in various plants; however, except growth phytohormones, specific functional metabolites involved in P. indica-mediated growth promotion are unknown. Here, we used a GC-MS based untargeted metabolite analysis to identify tomato (Solanum lycopersicum) metabolites whose levels were altered during P. indica-mediated growth promotion. Metabolomic multivariate analysis revealed several primary metabolites with altered levels, with putrescine induced most significantly in roots during the interaction. Further, our results indicated that P. indica modulates the arginine decarboxylase (ADC)-mediated putrescine biosynthesis pathway via induction of SlADC1 in tomato. P. indica did not promote growth in Sladc1-VIGS (virus-induced gene silencing of SlADC1) lines of tomato tomato and showed less colonization. Furthermore, using LC-MS/MS we showed that putrescine promoted growth by elevation of auxin (indole-3-acetic acid) and gibberellin (GA4, GA7) levels in tomato. In Arabidopsis (Arabidopsis thaliana) adc knock-out mutants, P. indica colonization also decreased and showed no plant growth promotion, and this response was rescued upon exogenous application of putrescine. Putrescine is also important for hyphal growth of P. indica, indicating that it is co-adapted by both host and microbe. Taken together, we conclude that putrescine is an essential metabolite and its biosynthesis in plants is crucial for P. indica-mediated plant growth promotion and fungal growth.
Spodoptera litura-mediated chemical defense is differentially modulated in older and younger systemic leaves of Solanum lycopersicum
(Springer Nature, 2018) Kundu, Anish; Mishra, Shruti; Vadassery, Jyothilakshmi
Main conclusion: Metabolite profling, biochemical assays, and transcript analysis revealed diferential modulation of specifc induced defense responses in local, older, and younger systemic leaves in Solanum lycopersicum upon Spodoptera litura herbivory. Plants reconfgure their metabolome upon herbivory to induce production of defense metabolites involved in both direct and indirect defenses against insect herbivores. Herbivory mediated leaf-to-leaf systemic induction pattern of primary and nonvolatile secondary metabolites is not well studied in tomato. Here, we show that, in cultivated tomato Solanum lycopersicum herbivory by generalist insect, Spodoptera litura results in diferential alteration of primary metabolites, majorly sugars and amino acids and specifc secondary metabolites in local, younger, and older systemic leaves. Cluster analysis of 55 metabolites identifed by GC–MS showed correlation between local and younger systemic leaves. Re-allocation of primary metabolites like glucose and amino acids from the local to systemic leaf was observed. Secondary metabolites chlorogenic acid, cafeic acid, and catechin were signifcantly induced during herbivory in systemic leaves. Among specifc secondary metabolites, chlorogenic acid and catechin signifcantly inhibits S. litura larval growth in all stages. Local leaf exhibited increased lignin accumulation upon herbivory. Diferential alteration of induced defense responses like reactive oxygen species, polyphenol oxidase activity, proteinase inhibitor, cell wall metabolites, and lignin accumulation was observed in systemic leaves. The metabolite alteration also resulted in increased defense in systemic leaves. Thus, comparative analysis of metabolites in local and systemic leaves of tomato revealed a constant re-allocation of primary metabolites to systemic leaves and diferential induction of secondary metabolites and induced defenses upon herbivory.
Synergistic effects of canopy chemistry and autogenic soil biota on a global invader
(John Wiley & Sons, 2023) Majumdar, Sudipto; Kaur, Harleen; Rinella, Matthew J.; Kundu, Anish; Vadassery, Jyothilakshmi; Erbilgin, Nadir; Callaway, Ragan M.; Cadotte, Marc W.; Inderjit
Soil biota have strong effects on plants, but we have a poor understanding of how plant chemistry might modify these effects. We examined the effect of soil biota associated with an exotic invasive tree, Prosopis juliflora, versus that associated with native species, from seven sites across India on conspecifics and two other plant species. We then measured changes in species-specific soil biota effects (identified as plant–soil feedbacks, PSFs) when leaf leachate from P. juliflora or from native plant species was added to soil containing respective live and sterile soil inoculum. We quantified the amino acid L-tryptophan from leaf leachate of P. juliflora, Leucaena leucocephala (another invader), and two native species. We also tested effects of P. juliflora or native species soil inoculum amendment of tryptophan on P. juliflora, P. cineraria and L. leucocephala across seven sites. We then quantified the microbially metabolized derivatives of tryptophan, phytohormone indole-3-acetic acid (IAA) and intermediates after adding tryptophan into P. juliflora and native soils. Soil biota associated with P. juliflora generated positive effects on conspecifics and L. leucocephala, but negative effects on the native congener P. cineraria. When P. juliflora leaf leachate was added to soil with live P. juliflora inoculum, PSFs became more positive for P. juliflora and other species, compared to leaf leachate amended with sterile soil inoculum. Native leaf leachate interacted weakly with soil biota to impact biomass of conspecifics and heterospecifics. There was roughly 10× more tryptophan in the leaf leachate of P. juliflora than in the leaf leachate of other species. Tryptophan generally increased positive PSFs associated with P. juliflora relative to soil biota associated with other plant species. When tryptophan was added to live P. juliflora soil, IAA and its intermediates were produced at five of seven sites, and at four of these sites soil biota from P. juliflora had positive PSFs. Synthesis. These results provide the first experimental evidence that a chemical leached from the leaves of an invader regulates PSFs. Our results indicate that canopy effects and PSFs, which are usually studied independently, can interact in ways that strongly affect conspecifics and neighbouring species.