Biology subjects

Chouhan, S.

Publications and source records attributed to Chouhan, S..

4 recordsLinked to original sources

bioRxiv2026

Euchromatin Peripheral Organization Follows Anterograde Signalling Under Anaesthetic Stress

Anterograde and retrograde signalling establish bidirectional communication between the nucleus and chloroplasts. Retrograde signals from chloroplasts regulate nuclear gene expression while anterograde signals from the nucleus coordinate chloroplast development and maintain cellular homeostasis. How this bidirectional signalling framework extends beyond locus-specific regulation to shape the global spatial organization of nuclear chromatin across tissues remains unclear. Although anaesthesia can alter chromatin organisation, the role of chloroplast dysfunction in these changes remains unclear. Here, we investigate how chloroplast dysfunction and anaesthesia influence euchromatin and heterochromatin organisation in Solanum lycopersicum seedlings across tissues with contrasting photosynthetic competence. Using confocal and super-resolution radial fluctuation (SRRF) imaging with quantitative multiparameter analysis, we identify distinct, tissue-specific chromatin responses to chloroplast disruption and anaesthesia. Notably, anaesthesia induces distinct spatial chromatin changes across tissues that are independent of chloroplast dysfunction, suggesting a direct nuclear response to anaesthesia rather than a chloroplast-mediated retrograde effect. These findings highlight chromatin topology as a potential quantitative biomarker of cellular disruption and provide a framework for investigating anterograde chloroplast-nucleus coordination and stress-responsive nuclear organisation in plants.

plant biology↗

bioRxiv2026

Efficient Mitigation of Copper Induced Cellular Dysfunction Using Chitosan Based Iron Oxide Nanoparticles

Copper is an essential redox-active micronutrient, but agricultural soils are increasingly contaminated by copper from mining, industrial discharge, and intensive agrochemical use, pushing concentrations beyond levels plants can tolerate. Excess copper triggers Fenton-like reactive oxygen species (ROS) generation, mitochondrial dysfunction, and impaired growth. Existing mitigation strategies, such as soil amendments, phytoremediation, antioxidants, and different chelators, have been explored to reduce copper toxicity, but their effectiveness can be limited by immobilization, poor specificity, and environmental persistence. The present work introduces a nanoparticle-based strategy for the direct sequestration of excess copper coupled with protection against the oxidative damage caused by copper stress. Here, we report MPA-iron oxide nanoparticles (MIONPs), sequentially functionalized with chitosan, glutathione, and 3-mercaptopropionic acid, designed to simultaneously scavenge ROS, restore redox homeostasis, and chelate copper via surface thiol groups. MIONPs showed a significant increase in copper binding capacity over bare iron oxide nanoparticles (BIONPs) and, in copper-stressed Solanum lycopersicum seedlings, significantly improved germination and root/shoot growth, reduced intracellular ROS, restored mitochondrial membrane potential, and preserved nuclear integrity. This integrated design establishes MIONPs as a promising, dual-function nanoplatform for sustainable copper stress management in agriculture.

plant biology↗

bioRxiv2025

Copper Stress Trigger Organelles Communication and Chromatin Condensation Leading to Cell Death in Solanum lycopersicum

Copper (Cu) is a vital micronutrient for plants but becomes highly toxic when present in excess, disrupting redox balance and damaging cellular structures. While the physiological and mitochondrial responses to Cu toxicity are well-documented, the nuclear-level consequences, particularly chromatin remodeling and gene regulatory changes, remain poorly understood. In this study, we used the root apex of Solanum lycopersicum as a model system to explore how increasing copper concentrations affect organelle integrity, stress signaling, and nuclear architecture. Using confocal and super-resolution imaging with organelle-specific markers and immunostaining, we observed that mitochondria was the earliest affected to Cu stress, exhibiting fragmentation, membrane depolarization, and cytochrome c release led to reactive oxygen species (ROS) accumulation, activation of AMPK, suppression of mTOR signaling, and nuclear translocation of NRF2. Critically, we found that copper exposure induced profound nuclear alterations, including shrinkage, lobulation, peripheral chromatin tethering, and global condensation events tightly correlated with stress signaling. H3K4me3 immunostaining revealed a shift from active euchromatin to condensed, transcriptionally silent states, leading to membrane rupture and cell death in root tip cells. Our findings show that the nucleus actively integrates organelle-derived stress signals, with chromatin remodeling as a key marker of copper toxicity. This highlights potential for chromatin-based diagnostics and stress-resilient crop breeding. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=86 SRC="FIGDIR/small/665307v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@15a3595org.highwire.dtl.DTLVardef@1740149org.highwire.dtl.DTLVardef@1007f24org.highwire.dtl.DTLVardef@19b1a20_HPS_FORMAT_FIGEXP M_FIG C_FIG

plant biology↗

bioRxiv2025

A Hierarchical Cascade of Organellar Silencing and their Regeneration under Anaesthetic Stress in Plants

Anaesthetics are pharmacological drugs that temporarily inhibit neural activity by acting on voltage-gated sodium channels and GABA receptors. Although their neurological mechanisms are well-defined, their wider cellular effects, especially in non-neuronal systems, are inadequately understood d. This study utilized Solanum lycopersicum plants root apex cells as a transparent model to examine anaesthetic-induced subcellular alterations via live-cell fluorescence imaging, immunostaining, and super-resolution microscopy. Our findings, first of its kind, demonstrate the initial comprehensive model of sequential causal structure and hierarchical cascade of organelle collapse of different but important organelles such as mitochondria, lysosome, vesicles trafficking and nuclear architectures under anaesthesia in plants. The nucleus is identified as the most important controller of recovery potential and cellular fate. In a time dependent experiment, we found that plant cells exposed to lidocaine for up to four hours could still recover mitochondrial potential, lysosomal function, and nuclear integrity when anaesthesia is removed. However, beyond four hours, the damage, especially to the nucleus, was irreversible, and cells proceeded to programmed cell death. Our data further demonstrate that organelle functions can recover after brief exposure to anaesthetic stress. However, prolonged exposure prevents recovery, resulting in the irreversible degradation of the nucleus leading to complete cell death. The results present novel targets for preventative therapies, such as mitochondrial antioxidants, lysosomal stabilizers, and nuclear structural protectants that could mitigate anaesthetic-induced damage.

plant biology↗