Institutional Publications
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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 Role of WRKY transcription factors in plant defense against lepidopteran insect herbivores: an overview(Springer Nature Publishing AG, 2021) Kundu, Pritha; Vadassery, JyothilakshmiPlants, in nature are challenged by various environmental stresses (both biotic and abiotic), which distort the plant growth, development and crop yield. A wide range of insect herbivores attack plants across the globe, throughout the year, causing huge loss to the productivity of crop species. Being sessile, the plants respond to the crisis using a wide range of defense responsive elements which at the transcriptional level, includes the transcription factors, like WRKY, NAC, AP2/ERF, MYB, MYC, bZIP, bHLH and others. Increasing evidences suggest a pivotal role of WRKY TFs in the regulation of plant defense response against herbivory in Arabidopsis and other important crop plants. Unlike pathogenic attack, very limited information is available on the role of different WRKYs in herbivore-plant interaction. In this review, we will thus majorly focus on the role of WRKY transcription factors and its regulation in response to herbivore attack while summarizing the recent developments from the field of transcriptional, post-transcriptional and epigenetic regulation of WRKYs in response to herbivory attack with the prospects for future implementation in research.Item Piriformospora indica recruits host-derived putrescine for growth promotion in plants(Oxford University Press, 2022) Kundu, Anish; Mishra, Shruti; Kundu, Pritha; Jogawat, Abhimanyu; Vadassery, JyothilakshmiGrowth 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.
