Institutional Publications
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Item RAV1 family members function as transcriptional regulators and play a positive role in plant disease resistance(John Wiley & Sons, 2023) Chandan, Ravindra Kumar; Kumar, Rahul; Swain, Durga Madhab; Ghosh, Srayan; Bhagat, Prakash Kumar; Patel, Sunita; Bagler, Ganesh; Sinha, Alok Krishna; Jha, GopaljeePhytopathogens pose a severe threat to agriculture and strengthening plant defense response is an important strategy for disease control. Here, we report that AtRAV1, an AP2 and B3 domain-containing transcription factor is required for basal plant defense in Arabidopsis thaliana. The atrav1 mutant lines demonstrate hyper-susceptibility against fungal pathogens (Rhizoctonia solani and Botrytis cinerea) while AtRAV1 overexpressing (OE) lines exhibit disease resistance against them. Enhanced expression of various defense genes and activation of MAP kinases (AtMPK3 and AtMPK6) are observed in the R. solani infected OE lines, but not in the atrav1 mutant plants. In-vitro phosphorylation assay suggests AtRAV1 to be a novel phosphorylation target of AtMPK3. The bimolecular fluorescence complementation and yeast two-hybrid assay support physical interactions between AtRAV1 and AtMPK3. Overexpression of the native as well as phospho-mimic but not the phospho-defective variant of AtRAV1 impart disease resistance in the atrav1 mutant A. thaliana lines. On the other hand, overexpression of AtRAV1 fails to impart disease resistance in the atmpk3 mutant. These analyses emphasize that AtMPK3-mediated phosphorylation of AtRAV1 is important for the elaboration of defense response in A. thaliana. Considering that RAV1 homologs are conserved in diverse plant species, we propose that they can be gainfully deployed to impart disease resistance in agriculturally important crop plants. Indeed, overexpression of SlRAV1 (a member of the RAV1 family) imparts disease tolerance against not only fungal (R. solani and B. cinerea) but also against bacterial (Ralstonia solanacearum) pathogens in tomato, while silencing of the gene enhances disease susceptibility.Item Heterologous overexpression of PDH45 gene of pea provides tolerance against sheath blight disease and drought stress in rice(Elsevier B.V., 2022) Sahoo, Ranjan Kumar; Chandan, Ravindra Kumar; Swain, Durga Madhab; Tuteja, Narendra; Jha, GopaljeeBiotic and abiotic stress tolerant crops are required for sustainable agriculture as well as ensuring global food security. In a previous study, we have reported that heterologous overexpression of pea DNA helicase (PDH45), a DEAD-box family member protein, provides salinity stress tolerance in rice. The improved management of photosynthetic machinery and scavenging of reactive oxygen species (ROS) are associated with PDH45 mediated salinity stress tolerance. However, the role of PDH45 in biotic and other abiotic stress (drought) tolerance remains unexplored. In the present study, we have generated marker-free transgenic IR64 rice lines that overexpress PDH45 under the CaMV35S promoter. The transgenic rice lines exhibited a significant level of tolerance against sheath blight disease, caused by Rhizoctonia solani, a polyphagous necrotrophic fungal pathogen. The defense as well as antioxidant responsive marker genes were significantly upregulated in the PDH45 overexpressing (OE) rice lines, upon pathogen infection. Moreover, the OE lines exhibited tolerance to drought stress and various antioxidant as well as drought responsive marker genes were significantly upregulated in them, upon drought stress. Overall, the current study emphasizes that heterologous overexpression of PDH45 provides abiotic as well as biotic stress tolerance in rice. Tolerance against drought as well as sheath blight disease by overexpression of a single gene (PDH45) signifies the practical implication of the present study. Moreover, considering the conserved nature of the gene in different plant species, we anticipate that PDH45 can be gainfully deployed to impart tolerance against multiple stresses in agriculturally important crops.Item Bacteria-fungal confrontation and fungal growth prevention assay(Bio-protocol LLC., 2018) Kumar, Rahul; Swain, Durga Madhab; Yadav, Sunil Kumar; Tyagi, Isha; Kumar, Rajeev; Das, Joyati; Ghosh, Srayan; Jha, GopaljeeThere are some bacteria which can grow and multiply at the cost of living fungal biomass. They can potentially utilize fungi as a source of nutrients to forage over them. Such phenomenon is known as bacterial mycophagy, however, its mechanistic insights need to be explored to identify the molecules involved in mycophagy for potential utilization in controlling various fungal diseases. Recently we have demonstrated that a rice-associated bacteria Burkholderia gladioli strain NGJ1 exhibits mycophagous ability on several fungi, including Rhizoctonia solani, the necrotrophic fungal pathogen causing sheath blight disease in rice. We hereby describe our validated and efficient methods used to study B. gladioli strain NGJ1-R. solani interactions. These methodologies would be useful for designing assays to study the confrontation between bacteria and fungi which in turn enable discovery of novel antifungal molecules from such bacteria.
