Publications of NIPGR Scientists
Permanent URI for this communityhttps://ndkr-library.nipgr.ac.in/handle/123456789/1
Browse
9 results
Search Results
Item Optimizing photosynthesis by targeting light signaling transcriptional networks(Oxford University Press, 2026) Sanyal, Rajarshi; Ranjan, AashishLight serves as a crucial environmental signal for plants besides providing energy for photosynthesis. Photomorphogenesis, light-induced plant developmental responses, involves photoreceptors perceiving light signals to initiate signaling cascades with downstream transcriptional networks. Moreover, light is also absorbed by photopigments to drive photosynthetic light reactions, providing energy for growth and metabolism. As light serves as a primary cue for both photomorphogenesis and photosynthesis, a crosstalk between the two processes is anticipated. While transcriptional regulation of photomorphogenesis is investigated in detail, our understanding of the transcriptional control of photosynthesis remains limited. Recent studies have shown the involvement of photoreceptors and key light-signaling transcription factors, such as PHYTOCHROME-INTERACTING FACTORs (PIFs) and ELONGATED HYPOCOTYL 5 (HY5), in the regulation of photosynthesis. This review not only highlights the transcriptional regulation of photosynthesis but also provides a broader perspective on the involvement of key transcription factors of photomorphogenesis in the regulation of photosynthesis. The review further discusses strategies to investigate and manipulate the light signaling transcriptional regulatory networks for optimizing photosynthetic efficiency.Item Nutrient use efficiency promoted hormonal crosstalk and stomatal dynamics in wheat under the co-impact of arsenic and drought(Elsevier B.V., 2025) Khatoon, Narjis Saba; Khan, Asna; Bhatia, Priyanka; Vadassery, Jyothilakshmi; Gupta, MeetuThis study presents the interlink of Nutrient use efficiency (NUE) influenced hormone and stomatal dynamics, in enhancing photosynthesis under the co-impact of drought (D) and arsenic (As) in wheat. We analyzed how nitrogen (N) and phosphorus (P) supplementation under D+As modulates these interactions with jasmonic acid (JA) and sucrose, as central regulators. Enhanced JA by NP-enrichment reduced abscisic-acid (ABA) and salicylic-acid (SA) production to promote stomatal opening via sugar-transporter-proteins; TaSTP12, TaSTP51, and TaKAT-like1. Computational docking confirms strong interaction between JA, TaMYB84 and TaSTP’s (TaSTP12, TaSTP51) suggesting a functional complex that facilitates sucrose osmoregulation. This influences stomatal opening which promotes gas-exchange for better photosynthesis. Additionally, we highlight the correlation between stomatal dynamics and NP-use efficiency. The NP-promoted photosynthesis, phosphorus-use efficiency (PnPUE), and TaPHT1. 10 ensures Pi availability for Krebs-cycle. This improves non-photochemical quenching (NPQ), for ATP production, boosting CO2 assimilation. Moreover, the increased photosynthetic-nitrogen-use efficiency (PnNUE), along with TaNRT2.1, and TaAMT1.1 augmented rubisco activity, thereby increasing photosynthesis. NP-supplementation also boosts ASC-GSH cycle, which safeguards the rubisco enzyme and light-harvesting-complex. These processes optimize photosynthesis to maintain starch reserves and sustain wheat productivity under D+As. Our findings provide valuable insights into NP-mediated photosynthetic regulation and underscore the crucial role of NUE in optimizing this process.Item Integration of metabolite and transcriptome profiles of cultivated and wild rice to unveil gene regulatory networks and key genes determining rice source and sink strength(Springer Nature Publishing AG, 2025) Singh, Anuradha; Mathan, Jyotirmaya; Dwivedi, Aditi; Rani, Ruchi; Ranjan, AashishTargeting source and sink strength for crop yield increase requires a comprehensive genetic and metabolic understanding of desirable source and sink features. We performed comprehensive metabolite and transcriptomic comparisons of the photosynthetic flag leaves and milky-stage developing grains of two cultivated rice varieties (Oryza sativa L. ssp. Indica cv. IR64 and Oryza sativa L. ssp. Japonica cv. Nipponbare) and two wild rice accessions (Oryza rufipogon and Oryza australiensis). The selected wild rice accessions had stronger source strength as evidenced by a higher photosynthesis rate and more abundance of primary metabolites in the photosynthetic leaves than the cultivated varieties. In contrast, cultivated varieties had efficient sink as grains were bigger and accumulated more sugars, amino acids, and fatty acids than the selected wild rice. Transcriptomic analyses identified 9,309 genes for efficient source in wild rice, enriched for biological pathways related to photosynthesis, carbohydrate metabolism, and sucrose transport. 7,062 genes, enriched for starch biosynthesis and lipid metabolism, were associated with the efficient sink strength in the cultivated varieties. Gene co-expression networks showed 267 hub genes for source strength in wild rice that included important genes for photosynthetic reactions and sucrose metabolism. 196 hub genes for sink strength in cultivated rice included genes involved in sucrose, amino acid, and fatty acid metabolism. Gene co-expression modules further identified the candidate transcription regulators, such as zinc finger proteins and NAC for source strength and MYB55/80 and MADS64 for sink strength. Moreover, our analyses suggested a complex interplay of phytohormones regulating rice source and sink strength.Item Revisiting development and physiology of wild rice relatives for crop improvement and climate resilience(Springer Nature Publishing AG, 2025) Mathan, Jyotirmaya; Dwivedi, Aditi; Ranjan, AashishIncreasing rice yield and productivity under changing climatic conditions is imperative for sustainable food security, given rice is a major staple crop around the world. Natural variation in crop plants, including wild relatives, offers remarkable genetic variability to explore the desirable developmental and physiologic traits for crop improvement. Wild relatives of rice, with distinct developmental and physiologic features compared to cultivated varieties, are the potential genetic and genomic resource for rice yield increases under changing climate. A thorough genetic basis of rice developmental and architectural changes during domestication is now established with the identification and characterization of domestication genes. Photosynthetically efficient wild rice accessions, with desirable developmental, physiologic, and metabolic traits, have been identified in recent years that could be instrumental for rice improvement. While several abiotic and biotic stress-tolerant wild relatives of rice along with the associated genetic loci have been identified over the years, a comprehensive insight into the desirable developmental and physiologic attributes of the wild rice is limited. Moreover, the usage of wild rice is not streamlined in rice-improvement programs due to genetic and genomic constraints. In this review, we summarize the desirable developmental and physiologic features of wild rice species that can be exploited for combining yield increases with climate resilience in rice-improvement programs.Item Regulation of photosynthesis by mitogen-activated protein kinase in rice: antagonistic adjustment by OsMPK3 and OsMPK6(Springer Nature Publishing AG, 2023) Jonwal, Sarvesh; Rengasamy, Balakrishnan; Sinha, Alok KrishnaPhotosynthesis is the basis of almost all life on earth and is the main component of crop yield that contributes to the carbohydrate partitioning to the grains. Maintaining the photosynthetic efficiency of plants in challenging environmental conditions by regulating the associated factors is a potential research arena which will help in the improvement of crop yield. Phosphorylation is known to play a pivotal role in the regulation of photosynthesis. Mitogen Activated Protein Kinases (MAPKs) cascade although known to regulate a diverse range of processes does not have any exact reported function in the regulation of photosynthesis. To elucidate the regulatory role of MAPKs in photosynthesis we investigated the changes in net photosynthesis rate and related parameters in DEX inducible over-expressing (OE) lines of two members of MAPK gene family namely, OsMPK3 and OsMPK6 in rice. Interestingly, significant changes were found in net photosynthesis rate and related physiological parameters in OsMPK3 and OsMPK6-OE lines compared to its wild-type relatives. OsMPK3 and OsMPK6 have regulatory effects on nuclear-encoded photosynthetic genes. Untargeted metabolite profiling reveals a higher accumulation of sugars and their derivatives in MPK6 overexpressing plants and a lower accumulation of sugars and organic acids in MPK3 overexpressing plants. The accumulation of amino acids was found in abundance in both MPK3 and MPK6 overexpressing plants. Understanding the effects of MPK3 and MPK6 on the CO2 assimilation of rice plants under normal growth conditions, will help in devising strategies that can be extended for crop improvement.Item SiHSFA2e regulated expression of SisHSP21.9 maintains chloroplast proteome integrity under high temperature stress(Springer Nature Publishing AG, 2022) Singh, Roshan Kumar; Muthamilarasan, Mehanathan; Prasad, ManojHigh temperature-induced crop failures are prominent nowadays in major staples, including rice, wheat, and maize; however, crops such as foxtail millet (Setaria italica) are resilient to temperature stress. In this study, a novel small heat shock protein of foxtail millet, SisHSP21.9, is identified and characterized for its role in conferring tolerance to high-temperature stress. SisHSP21.9 is a panicoid-specific gene, which is highly upregulated during high-temperature in leaves, and the protein is localized in the chloroplast. Its expression is directly regulated by heat shock factor, SiHSFA2e, during temperature stress. Further, overexpression of SiHSP21.9 in rice enhanced the survival of transgenics during high-temperature stress (> 80% survival frequency), and the transgenic lines showed improved plant architecture and overall grain yield. Compared to WT plants, transgenic lines maintained optimal photosynthesis rates with higher photosystem efficiencies at high temperatures, and this is conferred through protecting the components of photosystems, chlorophyll-binding proteins, and chloroplast-localized functional proteins by SisHSP21.9. Prolonged high-temperature stress showed minimal damage to chloroplast proteins resulting in comparatively lower yield loss (35–37%) in transgenic lines. Altogether, the study suggests that SisHSP21.9 is a potential candidate for designing thermotolerant crops for climate-resilient agriculture; however, further research is needed because tolerance to abiotic stresses is polygenic.Item Regulation of photosynthetic light reaction proteins via reversible phosphorylation(Elsevier B.V., 2022) Jonwal, Sarvesh; Verma, Neetu; Sinha, Alok KrishnaThe regulation of photosynthesis occurs at different levels including the control of nuclear and plastid genes transcription, RNA processing and translation, protein translocation, assemblies and their post translational modifications. Out of all these, post translational modification enables rapid response of plants towards changing environmental conditions. Among all post-translational modifications, reversible phosphorylation is known to play a crucial role in the regulation of light reaction of photosynthesis. Although, phosphorylation of PS II subunits has been extensively studied but not much attention is given to other photosynthetic complexes such as PS I, Cytochrome b6f complex and ATP synthase. Phosphorylation reaction is known to protect photosynthetic apparatus in challenging environment conditions such as high light, elevated temperature, high salinity and drought. Recent studies have explored the role of photosynthetic protein phosphorylation in conferring plant immunity against the rice blast disease. The evolution of phosphorylation of different subunits of photosynthetic proteins occurred along with the evolution of plant lineage for their better adaptation to the changing environment conditions. In this review, we summarize the progress made in the research field of phosphorylation of photosynthetic proteins and highlights the missing links that need immediate attention.Item High photosynthesis rate in two wild rice species is driven by leaf anatomy mediating high Rubisco activity and electron transport rate(Oxford University Press, 2021) Mathan, Jyotirmaya; Singh, Anuradha; Jathar, Vikram; Ranjan, AashishThe importance of increasing photosynthetic efficiency for sustainable crop yield increases to feed the growing world population is well recognized. The natural genetic variation for leaf photosynthesis in crop plants is largely unexploited for increasing genetic yield potential. The genus Oryza, including cultivated rice and wild relatives, offers tremendous genetic variability to explore photosynthetic differences, and underlying biochemical, photochemical, and developmental bases. We quantified leaf photosynthesis and related physiological parameters for six cultivated and three wild rice genotypes, and identified photosynthetically efficient wild rice accessions. Fitting A/Ci curves and biochemical analyses showed that the leaf photosynthesis in cultivated rice varieties, IR64 and Nipponbare, was limited due to leaf nitrogen content, Rubisco activity, and electron transport rate compared to photosynthetically efficient accessions of wild rice Oryza australiensis and Oryza latifolia. The selected wild rice accessions with high leaf photosynthesis per unit area had striking anatomical features, such as larger mesophyll cells with more chloroplasts, fewer mesophyll cells between two consecutive veins, and higher mesophyll cell and chloroplast surface area exposed to intercellular space. Our results show the existence of desirable variations in Rubisco activity, electron transport rate, and leaf anatomical features in the rice system itself that could be targeted for increasing the photosynthetic efficiency of cultivated rice varieties.Item Sucrose transport and metabolism control carbon partitioning between stem and grain in rice(Oxford University Press, 2021) Mathan, Jyotirmaya; Singh, Anuradha; Ranjan, AashishThe source-sink relationship is key to overall crop performance. Detailed understanding of the factors that determine source-sink dynamics is imperative for the balance of biomass and grain yield in crop plants. We investigated the differences in the source-sink relationship between a cultivated rice Oryza sativa cv. Nipponbare and a wild rice Oryza australiensis that show striking differences in biomass and grain yield. Oryza australiensis, accumulating higher biomass, not only showed higher photosynthesis per unit leaf area but also exported more sucrose from leaves than Nipponbare. However, grain features and sugar levels suggested limited sucrose mobilization to the grains in the wild rice due to vasculature and sucrose transporter functions. Low cell wall invertase activity and high sucrose synthase cleavage activity followed by higher expression of cellulose synthase genes in Oryza australiensis stem utilized photosynthates preferentially for the synthesis of structural carbohydrates, resulting in high biomass. In contrast, the source-sink relationship favored high grain yield in Nipponbare via accumulation of transitory starch in the stem, due to higher expression of starch biosynthetic genes, which is mobilized to panicles at the grain filling stage. Thus, vascular features, sucrose transport, and functions of sugar metabolic enzymes explained the differences in the source-sink relationship between Nipponbare and Oryza australiensis.