Biology subjects

Rupasinghe, T.

Publications and source records attributed to Rupasinghe, T..

5 recordsLinked to original sources

bioRxiv2025

Thermotolerance in Chia (Salvia hispanica L.) is Mediated by Rapid Heat-Induced Transcriptomic Reprogramming and Lipid Remodelling in Leaves

Heat stress poses a significant threat to crop productivity; however, the thermotolerance mechanisms in underutilised oilseed crops, such as chia (Salvia hispanica L.), remain poorly understood. Despite the growing interest in chia as a rich source of {omega}-3 fatty acids, its molecular response to heat stress, particularly in vegetative tissues, has not been explored. We conducted transcriptomic and lipidomic profiling to examine how chia leaves respond to short-term (3 h) and prolonged (27 h) heat stress, followed by recovery under ambient conditions. Heat stress induced differential expression in over 20% of transcripts in chia leaves, with distinct patterns involving Ca{superscript 2} signalling, heat shock factors, and other biological pathways contributing to cellular homeostasis. Gene expression and lipid profiles in chia leaves responded dynamically to both short-term (3 h) and prolonged (27 h) heat stress (38{degrees}C/20{degrees}C). An almost complete return to baseline was observed, with all but 0.3% of heat-responsive genes reverting to control expression levels after 24 h. Our analysis confirms the role of Ca{superscript 2}-mediated signalling pathways and molecular chaperones, including heat shock proteins and heat shock factors, which have been previously shown to contribute to maintaining cellular function during heat stress in other plant species. Among 287 annotated lipid species, TGs exhibited the most significant and reversible changes (>2-fold), suggesting their involvement in membrane remodelling. Our findings reveal adaptive mechanisms in chia that may open avenues for enhancing thermotolerance in other heat-sensitive oilseed crops. SIGNIFICANCE STATEMENTUnderstanding how crops respond to heat stress is crucial as global temperatures rise. This study indicates that in chia (Salvia hispanica), pathways responding to heat stress, like calcium signalling and heat shock proteins, are rapidly activated, and leaf triacylglycerol levels rise under heat stress before returning to baseline during recovery. By demonstrating near-complete recovery of gene expression following heat exposure, these findings highlight mechanisms of thermotolerance that may support improved stress tolerance in other crops.

plant biology↗

bioRxiv2022

Profound lipid dysregulation in mutant TDP-43 mice is ameliorated by the glucocerebrosidase 2 inhibitor ambroxol

The importance of dyslipidemia in amyotrophic lateral sclerosis (ALS) patients is increasingly recognised as a potential key mechanism driving disease onset, progression and survival. Evidence in familial ALS models suggests that lipid composition is significantly affected, however clinically relevant models have yet to be investigated. Using a powerful lipidomic approach, we uncover significant dysregulation of glycosphingolipid (GSL) metabolism in both the spinal cord and skeletal muscles of transgenic TDP-43Q331K mice. Treatment with the selective glucocerebrosidase 2 (GBA2) inhibitor ambroxol at symptom onset significantly improved motor and gait functions in TDP-43Q331K mice. Ambroxol treatment preserved motor neurons and neuromuscular junctions which was associated with modulation of GSL metabolism. Our study establishes significant lipid dysregulation in a clinically relevant model of ALS. Importantly, we show positive therapeutic outcomes in a mouse model of TDP-43 proteinopathy, suggesting that ambroxol may be a promising candidate to treat underlying dyslipidemia and symptoms of ALS.

neuroscience↗

bioRxiv2021

Low doses of the organic insecticide spinosad trigger lysosomal defects, ROS driven lipid dysregulation and neurodegeneration in flies

The plight of insect populations around the world and the threats it poses to agriculture and ecosystems has thrown insecticide use into the spotlight. Spinosad is an organic insecticide, considered less harmful to beneficial insects than synthetic insecticides, but its mode of action remains unclear. Using Drosophila, we show that low doses of spinosad reduce cholinergic response in neurons by antagonizing D6 nAChRs. D6 nAChRs are transported to lysosomes that become enlarged and accumulate upon spinosad treatment. Oxidative stress is initiated in the central nervous system, and spreads to midgut and disturbs lipid storage in metabolic tissues in a D6-dependent manner. Spinosad toxicity was ameliorated with the antioxidant N-Acetylcysteine amide (NACA). Chronic exposures lead to mitochondrial defects, severe neurodegeneration and blindness in adult animals. The many deleterious effects of low doses of this insecticide reported here point to an urgent need for rigorous investigation of its impacts on beneficial insects.

neuroscience↗

bioRxiv2020

Investigation of biochemical changes in barley inoculated with Trichoderma harzianum T-22 under salt stress

Increases in soil salinity impacts growth and yield of agricultural plants by inhibiting plant functions. Soil salinization is increasing because of the pressure of a growing population on food supply. Genetically modified crops and plant breeding techniques are being used to produce plants tolerant to salt stress. However, interactions of fungal endophytes with crop plants can also improve tolerance and is a less expensive approach. Here, the role of Trichoderma harzianum T-22 in alleviating NaCl-induced stress in two barley genotypes (cv. Vlamingh and cv. Gairdner) has been investigated. Metabolomics using GC-MS for polar metabolites and LC-MS for lipids was employed to provide insights into the biochemical changes in barley roots inoculated with fungus during the early stages of interaction. T. harzianum increased the root length of both genotypes under controlled and saline conditions. The fungus reduced the relative concentration of sugars in both genotypes and caused no change in organic acids under saline conditions. Amino acids decreased only in cv. Gairdner in fungus-inoculated roots under saline conditions. Lipid analyses suggest that salt stress causes large changes in the lipid profile of roots but that inoculation with fungus greatly reduces the extent of these changes. By studying a tolerant and a sensitive genotype and their responses to salt and inoculation we have been able to develop hypotheses about what lipid species and metabolites may be involved in the tolerant genotype for its tolerance to salt and how fungal inoculation changes the response of the sensitive genotype to improve its tolerance.

biochemistry↗

bioRxiv2019

Integrative Multi-Omics Analysis of Barley Genotypes Shows Differential Salt-Induced Osmotic Barriers and Response Phases Among Rootzones

The mechanisms underlying rootzone-localised responses to salinity stress during early stage of barley development remains fragmentary and elusive. Here, we performed a comprehensive detection of the multi-root-omes (transcriptomes, metabolomes, lipidomes) of a domesticated barley cultivar (Clipper) and a landrace (Sahara) with seedling root growth maintained and restricted in response to salt stress, respectively. Novel generalized linear models were designed to determine differentially expressed genes (DEG) or abundant metabolites (DAM) specific to salt treatments, genotypes, or rootzones (meristematic Z1, elongation Z2, maturation Z3). Based on pathway over-representation of the DEG and DAM, phenylpropanoid biosynthesis is the most statistically over-represented biological pathways among all salinity responses observed. Together with the histological evidence, an intense salt-induced lignin impregnation was found only at the stelic cell wall of Clipper Z2, comparing to a unique elevation of suberin deposition across Sahara Z2. This suggests two differential salt-induced modulations of apoplastic flow between the genotypes. Based on global correlation network construction of the DEG and DAM, callose deposition that potentially adjusted the symplastic flow in roots was almost independent of salinity in rootzones of Clipper, but was markedly decreased in that of Sahara. Through closer examinations of molecular and hormonal clues, we further demonstrate that the salinity response in rootzones of Clipper were mostly at recovery phase, comparing to Sahara with rootzones retained at quiescence. Taken together, we propose that two distinctive salt tolerance mechanisms could exist in Clipper (growth-sustaining) and Sahara (salt-shielding), providing important clues for improving crop plasticity to cope with the deteriorating global salinization of soil.

plant biology↗