Institutional Publications
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Item Phosphorylation of AGO1a by MAP kinases is required for miRNA mediated resistance against Xanthomonas oryzae pv. oryzae infection in rice(Elsevier B.V., 2024) Singh, Kirti; Sharma, Deepika; Bhagat, Prakash Kumar; Tayyeba, Sumaira; Noryang, Stanzin; Sinha, Alok KrishnaBacterial leaf blight is a devastating disease caused by Xanthomonas oryzae pv. oryzae (Xoo) which causes severe crop loss in rice. The molecular mechanism that initiates defense against such pathogens remains unexplored. Reports have suggested crucial role of several miRNAs in regulating immune responses in plants. Argonaute (AGO) proteins have been implicated in imparting immunity against pathogens by using small RNAs as guide molecules. Here, we show that phosphorylation of rice AGO1a by MAP kinases is required for miRNA expression regulation during Xoo infection. AGO1a is induced in response to pathogen infection and is under the control of SA signaling pathway. The pathogen responsive MAP kinases MPK3, MPK4 and MPK6, interact with AGO1a in planta and can phosphorylate the protein in vitro. Overexpression of AGO1a extends disease resistance against Xoo in rice and leads to a higher accumulation of miRNAs. Conversely, overexpression of a non phosphorylatable mutant protein aggravates disease susceptibility and remarkably suppresses the miRNA expression levels. At a molecular level, phosphorylation of AGO1a by MAP kinase is required for increased accumulation of miRNAs during pathogen challenge. Taken together, the data suggests that OsAGO1a is a direct phosphorylation target of MAP kinases and this phosphorylation is crucial for its role in imparting disease resistance.Item AtSWEET11 and AtSWEET12 transporters function in tandem to modulate sugar flux in plants(John Wiley & Sons, 2023) Fatima, Urooj; Balasubramaniam, D.; Khan, Wajahat Ali; Kandpal, Manu; Vadassery, Jyothilakshmi; Arockiasamy, Arulandu; Senthil-Kumar, MuthappaThe sugar will eventually be exported transporter (SWEET) members in Arabidopsis, AtSWEET11 and AtSWEET12 are the important sucrose efflux transporters that act synergistically to perform distinct physiological roles. These two transporters are involved in apoplasmic phloem loading, seed filling, and sugar level alteration at the site of pathogen infection. Here, we performed the structural analysis of the sucrose binding pocket of AtSWEET11 and AtSWEET12 using molecular docking followed by rigorous molecular dynamics (MD) simulations. We observed that the sucrose molecule binds inside the central cavity and in the middle of the transmembrane (TM) region of AtSWEET11 and AtSWEET12, that allows the alternate access to the sucrose molecule from either side of the membrane during transport. Both AtSWEET11 and AtSWEET12, shares the similar amino acid residues that interact with sucrose molecule. Further, to achieve more insights on the role of these two transporters in other plant species, we did the phylogenetic and the in-silico analyses of AtSWEET11 and AtSWEET12 orthologs from 39 economically important plants. We reported the extensive information on the gene structure, protein domain and cis-acting regulatory elements of AtSWEET11 and AtSWEET12 orthologs from different plants. The cis-elements analysis indicates the involvement of AtSWEET11 and AtSWEET12 orthologs in plant development and also during abiotic and biotic stresses. Both in silico and in planta expression analysis indicated AtSWEET11 and AtSWEET12 are well-expressed in the Arabidopsis leaf tissues. However, the orthologs of AtSWEET11 and AtSWEET12 showed the differential expression pattern with high or no transcript expression in the leaf tissues of different plants. Overall, these results offer the new insights into the functions and regulation of AtSWEET11 and AtSWEET12 orthologs from different plant species. This might be helpful in conducting the future studies to understand the role of these two crucial transporters in Arabidopsis and other crop plants.Item Indian wheat genomics initiative for harnessing the potential of wheat germplasm resources for breeding disease-resistant, nutrient-dense, and climate-resilient cultivars(Frontiers Media S.A., 2022) Kumar, Sundeep; Jacob, Sherry R.; Mir, Reyazul Rouf; Vikas, V. K.; Kulwal, Pawan; Chandra, Tilak; Kaur, Satinder; Kumar, Uttam; Kumar, Suneel; Sharma, Shailendra; Singh, Ravinder; Prasad, Sai; Singh, Anju Mahendru; Singh, Amit Kumar; Kumari, Jyoti; Saharan, M. S.; Bhardwaj, Subhash Chander; Prasad, Manoj; Kalia, Sanjay; Singh, KuldeepWheat is one of the major staple cereal food crops in India. However, most of the wheat-growing areas experience several biotic and abiotic stresses, resulting in poor quality grains and reduced yield. To ensure food security for the growing population in India, there is a compelling need to explore the untapped genetic diversity available in gene banks for the development of stress-resistant/tolerant cultivars. The improvement of any crop lies in exploring and harnessing the genetic diversity available in its genetic resources in the form of cultivated varieties, landraces, wild relatives, and related genera. A huge collection of wheat genetic resources is conserved in various gene banks across the globe. Molecular and phenotypic characterization followed by documentation of conserved genetic resources is a prerequisite for germplasm utilization in crop improvement. The National Genebank of India has an extensive and diverse collection of wheat germplasm, comprising Indian wheat landraces, primitive cultivars, breeding lines, and collection from other countries. The conserved germplasm can contribute immensely to the development of wheat cultivars with high levels of biotic and abiotic stress tolerance. Breeding wheat varieties that can give high yields under different stress environments has not made much headway due to high genotypes and environmental interaction, non-availability of truly resistant/tolerant germplasm, and non-availability of reliable markers linked with the QTL having a significant impact on resistance/tolerance. The development of new breeding technologies like genomic selection (GS), which takes into account the G × E interaction, will facilitate crop improvement through enhanced climate resilience, by combining biotic and abiotic stress resistance/tolerance and maximizing yield potential. In this review article, we have summarized different constraints being faced by Indian wheat-breeding programs, challenges in addressing biotic and abiotic stresses, and improving quality and nutrition. Efforts have been made to highlight the wealth of Indian wheat genetic resources available in our National Genebank and their evaluation for the identification of trait-specific germplasm. Promising genotypes to develop varieties of important targeted traits and the development of different genomics resources have also been highlighted.Item RNA interference for improving disease resistance in plants and its relevance in this clustered regularly interspaced short palindromic repeats-dominated era in terms of dsRNA-based biopesticides(Frontiers Media S.A., 2022) Halder, Koushik; Chaudhuri, Abira; Abdin, Malik Z.; Majee, Manoj; Datta, AsisRNA interference (RNAi) has been exploited by scientists worldwide to make a significant contribution in the arena of sustainable agriculture and integrated pest management. These strategies are of an imperative need to guarantee food security for the teeming millions globally. The already established deleterious effects of chemical pesticides on human and livestock health have led researchers to exploit RNAi as a potential agri-biotechnology tool to solve the burning issue of agricultural wastage caused by pests and pathogens. On the other hand, CRISPR/Cas9, the latest genome-editing tool, also has a notable potential in this domain of biotic stress resistance, and a constant endeavor by various laboratories is in progress for making pathogen-resistant plants using this technique. Considerable outcry regarding the ill effects of genetically modified (GM) crops on the environment paved the way for the research of RNAi-induced double-stranded RNAs (dsRNA) and their application to biotic stresses. Here, we mainly focus on the application of RNAi technology to improve disease resistance in plants and its relevance in today’s CRISPR-dominated world in terms of exogenous application of dsRNAs. We also focused on the ongoing research, public awareness, and subsequent commercialization of dsRNA-based biocontrol products.Item Molecular characterization revealed the role of thaumatin-like proteins of bread wheat in stress response(Frontiers Media S.A., 2022) Sharma, Alok; Sharma, Himanshu; Rajput, Ruchika; Pandey, Ashutosh; Upadhyay, Santosh KumarThaumatin-like proteins (TLPs) are related to pathogenesis-related-5 (PR-5) family and involved in stress response. Herein, a total of 93 TLP genes were identified in the genome of Triticum aestivum. Further, we identified 26, 27, 39, and 37 TLP genes in the Brachypodium distachyon, Oryza sativa, Sorghum bicolor, and Zea mays genomes for comparative characterization, respectively. They could be grouped into small and long TLPs with conserved thaumatin signature motif. Tightly clustered genes exhibited conserved gene and protein structure. The physicochemical analyses suggested significant differences between small and long TLPs. Evolutionary analyses suggested the role of duplication events and purifying selection in the expansion of the TLP gene family. Expression analyses revealed the possible roles of TLPs in plant development and abiotic and fungal stress response. Recombinant expression of TaTLP2-B in Saccharomyces cerevisiae provided significant tolerance against cold, heat, osmotic, and salt stresses. The results depicted the importance of TLPs in cereal crops that would be highly useful in future crop improvement programs.Item Progress and prospects of concurrent or combined stress studies in plants(John Wiley & Sons, 2021) Mahalingam, Ramamurthy; Pandey, Prachi; Senthil-Kumar, MuthappaPlants growing under field conditions are often exposed to multiple abiotic and biotic stresses occurring simultaneously or sequentially. Biotic stressors often interact with abiotic stressors at the plant interphase, which makes the impact of their combination on plants remarkably variable, though differing with order and intensity of stresses, as well as plant species and pathotypes. In this article, we examine the major abiotic stress combinations, as well as abiotic-biotic stress combinations, and physiological and molecular responses of plants to these combined stresses. Utilizing the available literature, information on the phenomic and transcriptomic response of plants to the combined abiotic and biotic stresses, and the cross-talk during signalling is reviewed. A succinct discussion on the scope and application of combined abiotic and biotic stress studies highlighting major gaps and novel avenues for further research is articulated.Item Adaptive reprogramming during early seed germination requires temporarily enhanced fermentation-A critical role for alternative oxidase regulation that concerns also microbiota effectiveness(Frontiers Media S.A., 2021) Bharadwaj, Revuru; Noceda, Carlos; Mohanapriya, Gunasekharan; Kumar, Sarma Rajeev; Thiers, Karine Leitão Lima; Costa, José Hélio; Macedo, Elisete Santos; Kumari, Aprajita; Gupta, Kapuganti Jagadis; Srivastava, Shivani; Adholeya, Alok; Oliveira, Manuela; Velada, Isabel; Sircar, Debabrata; Sathishkumar, Ramalingam; Arnholdt-Schmitt, BirgitPlants respond to environmental cues via adaptive cell reprogramming that can affect whole plant and ecosystem functionality. Microbiota constitutes part of the inner and outer environment of the plant. This Umwelt underlies steady dynamics, due to complex local and global biotic and abiotic changes. Hence, adaptive plant holobiont responses are crucial for continuous metabolic adjustment at the systems level. Plants require oxygen-dependent respiration for energy-dependent adaptive morphology, such as germination, root and shoot growth, and formation of adventitious, clonal, and reproductive organs, fruits, and seeds. Fermentative paths can help in acclimation and, to our view, the role of alternative oxidase (AOX) in coordinating complex metabolic and physiological adjustments is underestimated. Cellular levels of sucrose are an important sensor of environmental stress. We explored the role of exogenous sucrose and its interplay with AOX during early seed germination. We found that sucrose-dependent initiation of fermentation during the first 12 h after imbibition (HAI) was beneficial to germination. However, parallel upregulated AOX expression was essential to control negative effects by prolonged sucrose treatment. Early downregulated AOX activity until 12 HAI improved germination efficiency in the absence of sucrose but suppressed early germination in its presence. The results also suggest that seeds inoculated with arbuscular mycorrhizal fungi (AMF) can buffer sucrose stress during germination to restore normal respiration more efficiently. Following this approach, we propose a simple method to identify organic seeds and low-cost on-farm perspectives for early identifying disease tolerance, predicting plant holobiont behavior, and improving germination. Furthermore, the research strengthens the view that AOX can serve as a powerful functional marker source for seed hologenomes.Item Plant phospholipase D: novel structure, regulatory mechanism, and multifaceted functions with biotechnological application(Taylor & Francis Group, 2022) Deepika, Deepika; Singh, AmarjeetPhospholipases D (PLDs) are important membrane lipid-modifying enzymes in eukaryotes. Phosphatidic acid, the product of PLD activity, is a vital signaling molecule. PLD-mediated lipid signaling has been the subject of extensive research leading to discovery of its crystal structure. PLDs are involved in the pathophysiology of several human diseases, therefore, viewed as promising targets for drug design. The availability of a eukaryotic PLD crystal structure will encourage PLD targeted drug designing. PLDs have been implicated in plants response to biotic and abiotic stresses. However, the molecular mechanism of response is not clear. Recently, several novel findings have shown that PLD mediated modulation of structural and developmental processes, such as: stomata movement, root growth and microtubule organization are crucial for plants adaptation to environmental stresses. Involvement of PLDs in regulating membrane remodeling, auxin mediated alteration of root system architecture and nutrient uptake to combat nitrogen and phosphorus deficiencies and magnesium toxicity is established. PLDs via vesicle trafficking modulate cytoskeleton and exocytosis to regulate self-incompatibility (SI) signaling in flowering plants, thereby contributes to plants hybrid vigor and diversity. In addition, the important role of PLDs has been recognized in biotechnologically important functions, including oil/TAG synthesis and maintenance of seed quality. In this review, we describe the crystal structure of a plant PLD and discuss the molecular mechanism of catalysis and activity regulation. Further, the role of PLDs in regulating plant development under biotic and abiotic stresses, nitrogen and phosphorus deficiency, magnesium ion toxicity, SI signaling and pollen tube growth and in important biotechnological applications has been discussed.Item Organic acids: Versatile stress response roles in plants(Oxford University Press, 2021) Panchal, Poonam; Miller, Anthony J; Giri, JitenderOrganic acids (OAs) are central to cellular metabolism. Many plant stress responses involve exudation of OAs at the root-soil interface that can improve soil mineral acquisition and toxic metal tolerance. Because of their simple structure, the Low Molecular Weight Organic Acids (LMWOAs) are widely studied. We discuss the conventional roles of OAs, along with some newly emerging roles in plant stress tolerance. OAs are more versatile in their role in plant stress tolerance and are efficient chelating agents when compared with other acids, such as amino acids. Root OA exudation is important in soil carbon sequestration. These functions are key processes combating climate change and helping with more sustainable food production. We briefly review the mechanisms behind enhanced biosynthesis, secretion and regulation of these activities under different stresses. Also, an outline of the transgenic approaches targeted towards the enhanced production and secretion of OAs is provided. A re-occurring theme of OAs in plant biology is their roles as either ‘acids’ modifying pH or ‘chelators’ binding metals or as ‘carbon sources’ for microbes. We argue that these multiple functions are key factors for understanding these molecules important roles in plant stress biology. Finally, we contemplate how the functions of OAs in plant stress responses can be made use of and what the important unanswered questions are.Item Regulation of stress responses in plants by calcium dependent protein kinases(John Wiley & Sons, 2021) Deepika; Mali, Komal Vitthalrao; Kumar, Amit; Singh, AmarjeetCalcium‐dependent protein kinases (CDPKs) represent the group of major calcium (Ca2+) sensors in plants. CDPKs comprise of peculiar structural features due to which they play a dual role of “Ca2+ sensor and responder” and decode the message from specific Ca2+ signature to phosphorylation events. Onset of most of the stresses results in increase in cytosolic Ca2+ level in plant cell. In depth functional analyses across plant species showed regulation of CDPK transcripts, activity, protein interactions and substrate targeting under biotic and abiotic stresses. Thus, vital role of CDPKs is proposed in transduction of stress triggered Ca2+ signaling to adaptive responses in plants. Genetic manipulations using CDPK genes could be vital in the agricultural biotechnology for imparting tolerance to biotic and abiotic stress, and better productivity. In this chapter, we provide an overview and update of CDPK gene family organization, CDPK domain structure and regulatory mechanism, the role of various CDPKs in abiotic stress, biotic stress signaling and responses in the model and crop plants.