Publications of NIPGR Scientists
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Item The Mediator complex subunit, OsMED26_2, modulates plant growth, seed set and seed traits related to starch quality in rice(Elsevier B.V., 2026) Prusty, Ankita; Malik, Naveen; Ranjan, Rajeev; Agarwal, Pinky; Parida, Swarup K.; Kapoor, Sanjay; Tyagi, Akhilesh K.The Mediator (MED) complex is a multi-subunit structure crucial for RNA polymerase II-dependent transcription in eukaryotes. In this study, we investigated the function of a seed-preferential subunit of the rice Mediator complex, namely, OsMED26_2, for the first time. Knockdown of OsMED26_2 in rice reduced plant height and altered panicle morphology with shorter panicles, lesser branching, and fewer seeds per panicle. OsMED26_2 knockdown also led to shorter grains with shorter length and chalky endosperm. A significantly higher percentage of grains with chalkiness (PGWC) and degree of chalky endosperm (DCE) was observed in OsMED26_2 knockdown lines. OsMED26_2-knockdown seeds contained lower starch levels and altered proportions of amylose and amylopectin. Scanning electron microscopy further showed that these changes caused irregular, round, and loosely packed starch granules in the endosperm, contributing to the chalky phenotype. Decreased amylose content and increased grain chalkiness were corroborated by the downregulation of the Waxy (Wx) gene, which is involved in amylose synthesis, and altered expression of AMY3A, CHALK5, FLO4, GPA3, and SUSY3 genes, which regulate grain chalkiness. Our findings demonstrate that OsMED26_2 is critical in regulating panicle architecture, impacting yield, and modulating starch level and composition to control grain chalkiness and thereby suggesting its functional significance especially in manipulating yield attributing grain cooking quality traits of rice.Item OsMED14_2, a tail module subunit of mediator complex, controls rice development and involves jasmonic acid(Elsevier B.V., 2024) Prusty, Ankita; Mehra, Poonam; Sharma, Shivam; Malik, Naveen; Agarwal, Pinky; Parida, Swarup K.; Kapoor, Sanjay; Tyagi, Akhilesh K.The Mediator complex is essential for eukaryotic transcription, yet its role and the function of its individual subunits in plants, especially in rice, remain poorly understood. Here, we investigate the function of OsMED14_2, a subunit of the Mediator tail module, in rice development. Overexpression and knockout of OsMED14_2 resulted in notable changes in panicle morphology and grain size. Microscopic analysis revealed impact of overexpression on pollen maturation, reflected by reduced viability, irregular shapes, and aberrant intine development. OsMED14_2 was found to interact with proteins involved in pollen development, namely, OsMADS62, OsMADS63 and OsMADS68, and its overexpression negatively affected the expression of OsMADS68 and the expression of other genes involved in intine development, including OsCAP1, OsGCD1, OsRIP1, and OsCPK29. Additionally, we found that OsMED14_2 overexpression influences jasmonic acid (JA) homeostasis, affecting bioactive JA levels, and expression of OsJAZ genes. Our data suggest OsMED14_2 may act as a regulator of JA-responsive genes through its interactions with OsHDAC6 and OsJAZ repressors. These findings contribute to better understanding of the Mediator complex's role in plant traits regulation.Item Major transcription factor families at the nexus of regulating abiotic stress response in millets: a comprehensive review(Springer Nature Publishing AG, 2024) Prusty, Ankita; Panchal, Anurag; Singh, Roshan Kumar; Prasad, ManojMillets stand out as a sustainable crop with the potential to address the issues of food insecurity and malnutrition. These small-seeded, drought-resistant cereals have adapted to survive a broad spectrum of abiotic stresses. Researchers are keen on unravelling the regulatory mechanisms that empower millets to withstand environmental adversities. The aim is to leverage these identified genetic determinants from millets for enhancing the stress tolerance of major cereal crops through genetic engineering or breeding. This review sheds light on transcription factors (TFs) that govern diverse abiotic stress responses and play role in conferring tolerance to various abiotic stresses in millets. Specifically, the molecular functions and expression patterns of investigated TFs from various families, including bHLH, bZIP, DREB, HSF, MYB, NAC, NF-Y and WRKY, are comprehensively discussed. It also explores the potential of TFs in developing stress-tolerant crops, presenting a comprehensive discussion on diverse strategies for their integration.Item OsJAZ11 regulates spikelet and seed development in rice(John Wiley & Sons, 2022) Mehra, Poonam; Pandey, Bipin K.; Verma, Lokesh; Prusty, Ankita; Singh, Ajit Pal; Sharma, Shivam; Malik, Naveen; Bennett, Malcolm J.; Parida, Swarup K.; Giri, Jitender; Tyagi, Akhilesh K.Seed size is one of the major determinants of seed weight and eventually, crop yield. As the global population is increasing beyond the capacity of current food production, enhancing seed size is a key target for crop breeders. Despite the identification of several genes and QTLs, current understanding about the molecular regulation of seed size/weight remains fragmentary. In the present study, we report novel role of a jasmonic acid (JA) signaling repressor, OsJAZ11 controlling rice seed width and weight. Transgenic rice lines overexpressing OsJAZ11 exhibited up to a 14% increase in seed width and ~30% increase in seed weight compared to wild type (WT). Constitutive expression of OsJAZ11 dramatically influenced spikelet morphogenesis leading to extra glume-like structures, open hull, and abnormal numbers of floral organs. Furthermore, overexpression lines accumulated higher JA levels in spikelets and developing seeds. Expression studies uncovered altered expression of JA biosynthesis/signaling and MADS box genes in overexpression lines compared to WT. Yeast two-hybrid and pull-down assays revealed that OsJAZ11 interacts with OsMADS29 and OsMADS68. Remarkably, expression of OsGW7, a key negative regulator of grain size, was significantly reduced in overexpression lines. We propose that OsJAZ11 participates in the regulation of seed size and spikelet development by coordinating the expression of JA-related, OsGW7 and MADS genes.Item OsJAZ11 regulates phosphate starvation responses in rice(Springer Nature Publishing AG, 2021) Pandey, Bipin K.; Verma, Lokesh; Prusty, Ankita; Singh, Ajit Pal; Bennett, Malcolm J.; Tyagi, Akhilesh K.; Giri, Jitender; Mehra, PoonamJasmonic Acid (JA) is a key plant signaling molecule which negatively regulates growth processes including root elongation. JAZ (JASMONATE ZIM-DOMAIN) proteins function as transcriptional repressors of JA signaling. Therefore, targeting JA signaling by deploying JAZ repressors may enhance root length in crops. In this study, we overexpressed JAZ repressor OsJAZ11 in rice to alleviate the root growth inhibitory action of JA. OsJAZ11 is a low phosphate (Pi) responsive gene which is transcriptionally regulated by OsPHR2. We report that OsJAZ11 overexpression promoted primary and seminal root elongation which enhanced Pi foraging. Expression studies revealed that overexpression of OsJAZ11 also reduced Pi starvation response (PSR) under Pi limiting conditions. Moreover, OsJAZ11 overexpression also suppressed JA signaling and biosynthesis as compared to wild type (WT). We further demonstrated that the C-terminal region of OsJAZ11 was crucial for stimulating root elongation in overexpression lines. Rice transgenics overexpressing truncated OsJAZ11ΔC transgene (i.e., missing C-terminal region) exhibited reduced root length and Pi uptake. Interestingly, OsJAZ11 also regulates Pi homeostasis via physical interaction with a key Pi sensing protein, OsSPX1. Our study highlights the functional connections between JA and Pi signaling and reveals JAZ repressors as a promising candidate for improving low Pi tolerance of elite rice genotypes.