Institutional Publications

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Author: search.filters.author.Ghosh, SrayanSubject: search.filters.subject.sheath blight disease

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    The host and pathogen myo-inositol-1-phosphate synthases are required for Rhizoctonia solani AG1-IA infection in tomato
    (John Wiley & Sons, 2024) Tyagi, Kriti; Chandan, Ravindra K.; Sahoo, Debashis; Ghosh, Srayan; Gupta, Santosh Kumar; Jha, Gopaljee
    The myo-inositol-1-phosphate synthase (MIPS) catalyses the biosynthesis of myo-inositol, an important sugar that regulates various physiological and biochemical processes in plants. Here, we provide evidence that host (SlMIPS1) and pathogen (Rs_MIPS) myo-inositol-1-phosphate synthase (MIPS) genes are required for successful infection of Rhizoctonia solani, a devastating necrotrophic fungal pathogen, in tomato. Silencing of either SlMIPS1 or Rs_MIPS prevented disease, whereas an exogenous spray of myo-inositol enhanced disease severity. SlMIPS1 was upregulated upon R. solani infection, and potentially promoted source-to-sink transition, induced SWEET gene expression, and facilitated sugar availability in the infected tissues. In addition, salicylic acid (SA)-jasmonic acid homeostasis was altered and SA-mediated defence was suppressed; therefore, disease was promoted. On the other hand, silencing of SlMIPS1 limited sugar availability and induced SA-mediated defence to prevent R. solani infection. Virus-induced gene silencing of NPR1, a key gene in SA signalling, rendered SlMIPS1-silenced tomato lines susceptible to infection. These analyses suggest that induction of SA-mediated defence imparts disease tolerance in SlMIPS1-silenced tomato lines. In addition, we present evidence that SlMIPS1 and SA negatively regulate each other to modulate the defence response. SA treatment reduced SlMIPS1 expression and myo-inositol content in tomato, whereas myo-inositol treatment prevented SA-mediated defence. We emphasize that downregulation of host/pathogen MIPS can be an important strategy for controlling diseases caused by R. solani in agriculturally important crops.
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    RS_CRZ1, a C2H2 type transcription factor is required for pathogenesis of Rhizoctonia solani AG1-IA in tomato
    (American Phytopathological Society, 2021) Ghosh, Srayan; Kant, Ravi; Pradhan, Amrita; Jha, Gopaljee
    Rhizoctonia solani is a necrotrophic fungal pathogen which causes disease in diverse plant species. In recent years, the genomic and transcriptomic studies have identified several candidate pathogenicity determinants of R. solani; however, most of them remain to be validated. In this study, we report a viral vector-based host induced gene silencing (HIGS) as well as a dsRNA (double stranded RNA) based approach to effectively downregulate genes of R. solani AG1-IA (BRS1 strain) during pathogenesis in tomato. We tested a few of the in-planta upregulated R. solani genes and observed that silencing of one of them i.e. RS_CRZ1 (a C2H2 type Zn finger transcription factor) significantly compromises the pathogenesis of R. solani in tomato. The RS_CRZ1 silenced plants not only exhibited significant reduction in disease symptoms, but the depth of pathogen colonization was also compromised. Furthermore, we identified the R. solani genes that were co-regulated with RS_CRZ1 during pathogenicity process. The HIGS mediated silencing of a few of them (CL1756Contig1; subtilisin like protease and CL1817Contig2; 2OG- Fe(II) oxygenase) compromised the pathogenesis of R. solani in tomato. The ectopic expression of RS_CRZ1 complemented the crz1 mutant of yeast and restored tolerance against various metal ion stress. Overall, our study reveals the importance of RS_CRZ1 in managing the hostile environment encountered during host colonization. Also, it emphasizes the relevance of HIGS and dsRNA-based gene silencing approach towards functional characterization of pathogenicity determinants of R. solani.