Publications of NIPGR Scientists

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    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, Gopaljee
    Phytopathogens 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.
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    Expression dynamics indicate the role of Jasmonic acid biosynthesis pathway in regulating macronutrient (N, P and K+) deficiency tolerance in rice (Oryza sativa L.)
    (Springer Nature Publishing AG, 2021) Deepika; Singh, Amarjeet
    Key message: Expression pattern indicates that JA biosynthesis pathway via regulating JA levels might control root system architecture to improve nutrient use efciency (NUE) and N, P, K+ defciency tolerance in rice. Abstract: Defciencies of macronutrients (N, P and K+) and consequent excessive use of fertilizers have dramatically reduced soil fertility. It calls for development of nutrient use efcient plants. Plants combat nutrient defciencies by altering their root system architecture (RSA) to enhance the acquisition of nutrients from the soil. Amongst various phytohormones, Jasmonic acid (JA) is known to regulate plant root growth and modulate RSA. Therefore, to understand the role of JA in macronutrient defciency in rice, expression pattern of JA biosynthesis genes was analyzed under N, P and K+ defciencies. Several members belonging to diferent families of JA biosynthesis genes (PLA1, LOX, AOS, AOC, OPR, ACX and JAR1) showed diferential expression exclusively in one nutrient defciency or in multiple nutrient defciencies. Expression analysis during developmental stages showed that several genes expressed signifcantly in vegetative tissues, particularly in root. In addition, JA biosynthesis genes were found to have signifcant expression under the treatment of diferent phytohormones, including Auxin, cytokinin, gibberellic acid (GA), abscisic acid (ABA), JA and abiotic stresses, such as drought, salinity and cold. Analysis of promoters of these genes revealed various cis-regulatory elements associated with hormone response, plant development and abiotic stresses. These fndings suggest that JA biosynthesis pathway by regulating the level of JA might control the RSA thus, it may help rice plant in combating macronutrient defciency.
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    Omega hydroxylated JA-Ile is an endogenous bioactive jasmonate that signals through the canonical jasmonate signaling pathway
    (Elsevier B.V., 2019) Jimenez-Aleman, Guillermo H.; Almeida-Trapp, Marilia; Fernández-Barbero, Gemma; Gimenez-Ibanez, Selena; Reichelt, Michael; Vadassery, Jyothilakshmi; Mithöfer, Axel; Caballero, Julio; Boland, Wilhelm; Solano, Roberto
    Jasmonates are fatty acid derivatives that control several plant processes including growth, development and defense. Despite the chemical diversity of jasmonates, only jasmonoyl-L-isoleucine (JA-Ile) has been clearly characterized as the endogenous ligand of the jasmonate co-receptors (COI1-JAZs) in higher plants. Currently, it is accepted that ω-hydroxylation of JA-Ile leads to inactivation of the molecule. This study shows that ω-hydroxylated JA-Ile (12-OH-JA-Ile) retains bioactivity and signals through the canonical JA-pathway. The results suggest that 12-OH-JA-Ile differentially activates a subset of JA-Ile co-receptors that may control and/or modulate particular jasmonate dependent responses. It is proposed that after a strong immune response mediated by JA-Ile, the ω-hydroxylated form modulates JA-Ile activated processes thereby improving plant resilience.