Publications of NIPGR Scientists
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Item Seed endophytic bacterium Bacillus velezensis and its lipopeptides acts as elicitors of defense responses against Fusarium verticillioides in maize seedlings(Springer Nature Publishing AG, 2023) Pal, Gaurav; Saxena, Samiksha; Kumar, Kanchan; Verma, Anand; Kumar, Deepak; Shukla, Pooja; Pandey, Ashutosh; Verma, Satish K.Purpose: The potential of endophytic bacteria to improve plant health has been well-established. In maize plants, studies have reported the antagonistic activity of endophytic bacteria against various kinds of phytopathogenic strains; however, the effect of lipopeptide inoculation on germinated seedlings and its underlying defense responses remain unexplored. In this study, we examined the effects of seed endophytic bacterium Bacillus velezensis and its lipopeptides in improving plant defense against Fusarium verticillioides in maize seedlings. Methods: In vitro germinated maize seedlings were treated with lipopeptides extracted from the B. velezensis, followed by inoculation with the phytopathogen Fusarium verticillioides. The lipopeptides were characterized using MALDI-TOF analysis and their effects on fungal colonization and defense gene expression were investigated. Polyphenol content was checked in the bacterium-ZMW8 as well as ZMW8 and Fusarium-inoculated seedlings through UHPLC. Results: Lipopeptide treatment to the maize seedling’s roots resulted in enhanced protection from the fungus with significant improvement in all the growth parameters measured. Antifungal lipopeptides were identified as bacillomycin D and fengycin. Confocal microscopy images revealed the heavy colonization of fungus on the seed and root surface of non-lipopeptide-treated seedlings. Gene expression analysis revealed upregulation of various defense response genes including ZmPR-1, ZmPR-4, ZmSOD-2, ZmLOX, ZmPDF1.2, and ZmERF in the roots of bacteria and lipopeptides-treated maize seedlings. Targeted metabolite analysis through UHPLC revealed the accumulation of antifungal polyphenols including p-coumaric acid, kaempferol, dihydrokaempferol (DHK), and dihydroquercetin (DHQ). Conclusions: The study highlights the potential of bacterial lipopeptides as elicitors of defense responses in maize seedlings against Fusarium infection.Item Interplay of neuronal and non-neuronal genes regulates intestinal DAF-16-mediated immune response during Fusarium infection of Caenorhabditis elegans(Nature Publishing Group, 2017) Nag, Papri; Aggarwal, Pooja Rani; Ghosh, Sudip; Narula, Kanika; Tayal, Rajul; Maheshwari, Nidhi; Chakraborty, Niranjan; Chakraborty, SubhraAlthough precisely controlled innate immune response is governed by conserved cellular events in phylogenetically diverse hosts, the underlying molecular mechanisms by which this process is regulated against a multi-host pathogen remain unknown. Fusarium oxysporum is a model multi-host pathogen, known to be associated with neuronal stress in humans and vascular wilt in plants. The interaction between innate immune and neuronal pathways is the basis of many diverse biological responses. How these processes are coordinated in response to fungal disease is not well understood. Here, we show that F. oxysporum f. sp. ciceri causes neuronal stress and intestinal disintegration, ultimately leading to the death of Caenorhabditis elegans. To explore the regulatory framework of Fusarium-associated disease, we analysed the gene expression during infection, integrated temporal gene expression, and network analysis with genetic inactivation data in Caenorhabditis elegans. We identified 1024 genes showing significant changes in expression (corrected P-values <0.05) in response to Fusarium infection. Co-expression network analysis of our data identified prognostic genes related to disease progression. These genes were dynamically expressed in various neuronal and non-neuronal tissues exhibiting diverse biological functions, including cellular homeostasis, organ patterning, stress response, and lipid metabolism. The RNA-seq analysis further identified shared and unique signalling pathways regulated by DAF-16/FOXO and SIR-2.1 linking neuronal stress, which facilitates negative regulation of intestinal innate immunity. Genetic analysis revealed that GCY-5 in ASE functions upstream of DAF-16, whereas ASI-specific SRD-1 regulates behavioural immunity. Overall, our results indicate that a ubiquitous response occurs during Fusarium infection mediated by highly conserved regulatory components and pathways, which can be exploited further for the identification of disease-responsive genes conserved among animals and plants. Finally, this study provided a novel insight into cross-species immune signalling and may facilitate the discovery of cellular therapeutic targets for Fusarium-associated disease.Item Discovery of molecular markers for Fusarium wilt via transcriptome sequencing of chickpea cultivars(Springer, 2015) Jain, Mukesh; Pole, Anil K.; Singh, Vikash K.; Ravikumar, Ramapura L.; Garg, RohiniThe wilt caused by Fusarium oxysporum f.sp. Ciceris is a major problem for chickpea. The large-scale discovery of DNA polymorphisms in different cultivars can provide insights into the genetic basis of phenotypic differences. In the present study, we sequenced the transcriptomes of four chickpea cultivars with contrasting response to Fusarium infection, including susceptible JG62 and resistant/tolerant ICCV2, K850 and WR315. Based on the analysis of their transcriptome sequences, we identified at least 303 polymorphic microsatellites, of which 64 % could be physically mapped on the chickpea genome. Further, we identified a total of 14,462 single nucleotide polymorphisms (SNPs) and 1864 insertions/deletions (InDels) among the chickpea cultivars analysed. More than 50 % of the SNPs and 19 % of the InDels were detected in the predicted coding regions, and about 46 % of these SNPs resulted in nonsynonymous changes. In addition, we identified at least 60 large-effect SNPs and 248 InDels that affected the integrity of the encoded protein. Several defence-related genes involved in different cellular processes were found to harbour nonsynonymous and/or large-effect SNPs and/or InDels. These data will provide functional markers and promising target genes for wilt resistance and present a valuable resource for molecular breeding for this important trait in chickpea.
