Erratum: The uppermost monoterpenes improving Cinnamomum camphora thermotolerance by serving signaling functions.

[This corrects the article DOI: 10.3389/fpls.2022.1072931.].

Concurrent Measurement of O2 Production and Isoprene Emission During Photosynthesis: Pros, Cons and Metabolic Implications of Responses to Light, CO2 and Temperature.

Traditional leaf gas exchange experiments have focused on net CO2 exchange (Anet). Here, using California poplar (Populus trichocarpa), we coupled measurements of net oxygen production (NOP), isoprene emissions and δ18O in O2 to traditional CO2/H2O gas exchange with chlorophyll fluorescence, and measured light, CO2 and temperature response curves. This allowed us to obtain a comprehensive picture of the photosynthetic redox budget including electron transport rate (ETR) and estimates of the mean assimilatory quotient (AQ = Anet/NOP). We found that Anet and NOP were linearly correlated across environmental gradients with similar observed AQ values during light (1.25 ± 0.05) and CO2 responses (1.23 ± 0.07). In contrast, AQ was suppressed during leaf temperature responses in the light (0.87 ± 0.28), potentially due to the acceleration of alternative ETR sinks like lipid synthesis. Anet and NOP had an optimum temperature (Topt) of 31°C, while ETR and δ18O in O2 (35°C) and isoprene emissions (39°C) had distinctly higher Topt. The results confirm a tight connection between water oxidation and ETR and support a view of light-dependent lipid synthesis primarily driven by photosynthetic ATP/NADPH not consumed by the Calvin-Benson cycle, as an important thermotolerance mechanism linked with high rates of (photo)respiration and CO2/O2 recycling.

Ampk-mediated regulation of cardiac energy metabolism: Implications for thermotolerance in Argopecten irradians irradians.

AMPK is a key regulator of metabolism in eukaryotes across various pathways related to energy regulation. Although extensive investigations of AMPK have been conducted in mammals and some model organisms, research on AMPK in scallops is comparatively limited. In this study, three AMPK family genes (AiAMPKα, AiAMPKß and AiAMPKγ) in scallop Argopecten irradians irradians were identified through genome scanning. Structure prediction and phylogenetic analyses of AiAMPKs were performed to determine their structural features and evolutionary relationships. Spatiotemporal expression patterns of AiAMPKs at different developmental stages and in healthy adult tissues were analyzed to elucidate the function of AiAMPKs in bay scallops' growth and development. The spatiotemporally specific expression of AiAMPKs implied their important roles in growth and development of bay scallops. Heat stress experiment was performed to determine the regulations of AiAMPKs in four kinds of thermosensitive tissues. Expression profiles revealed distinct molecular mechanisms of AiAMPKs in different tissues in response to heat stress: significant down-regulations in mobile hemocytes, but dominant up-regulations occurring in stationary gills, mantles and hearts. Functional verification including knock-down of AiAMPKα and inhibition of AiAMPK was separately conducted in the thermotolerant tissue heart at the post-transcription and translation levels. The thermotolerant index Arrhenius break temperature (ABT) showed a significant decrease and the rate-amplitude product (RAP) peaked earlier in the individuals after RNAi targeting AiAMPKα, displaying an earlier transition to anaerobic metabolism under heat stress, indicating an impairing ability of aerobic metabolism. After AiAMPK inhibition, widespread down-regulations of genes in key energy metabolism pathways, RNA polymerase II-mediated transcription, and aminoacyl-tRNA synthesis pathways were obviously observed, revealing the post-translational inhibition of AiAMPK hindered cardiac energy metabolism, basal transcription and translation. Overall, our findings provide evidences for exploring the molecular mechanisms of energy regulation in thermotolerant traits in bay scallops under ongoing global warming.

Heat shock factor ZmHsf17 positively regulates phosphatidic acid phosphohydrolase ZmPAH1 and enhances maize thermotolerance.

Heat stress (HS) adversely impacts plant growth, development and grain yield. Heat shock factors (Hsf), especially HsfA2 subclass, play a pivotal role in the transcriptional regulation of genes in response to HS. In this study, the coding sequence of maize ZmHsf17 was cloned. ZmHsf17 contains conserved domains: DNA binding, oligomerization and transcriptional activation. The protein was nuclear localized and had transcription activation activity. Yeast two hybrid and split luciferase complementary assays confirmed the interaction of ZmHsf17 with members of the maize HsfA2 subclass. Overexpression of ZmHsf17 in maize significantly increased chlorophyll content and net photosynthesis rate of maize leaves, and enhanced the stability of cellular membranes. Through integrative analysis of ChIP-seq and RNA-seq datasets, ZmPAH1, encoding phosphatidic acid phosphohydrolase of lipid metabolic pathways, was identified as a target gene of ZmHsf17. The promoter fragment of ZmPAH1 was bound by ZmHsf17 in protein-DNA interaction experiments in vivo and in vitro. Lipidomic data also indicates that the overexpression of ZmHsf17 increased levels of some critical membrane lipid components of maize leaves under HS. This research provides new insights into the role of the ZmHsf17-ZmPAH1 module in regulating thermotolerance in maize.

Identification and Analysis of the Superoxide Dismutase (SOD) Gene Family and Potential Roles in High-Temperature Stress Response of Herbaceous Peony (Paeonia lactiflora Pall.).

The herbaceous peony (Paeonia lactiflora Pall.) plant is world-renowned for its ornamental, medicinal, edible, and oil values. As global warming intensifies, its growth and development are often affected by high-temperature stress, especially in low-latitude regions. Superoxide dismutase (SOD) is an important enzyme in the plant antioxidant systems and plays vital roles in stress response by maintaining the dynamic balance of reactive oxygen species (ROS) concentrations. To reveal the members of then SOD gene family and their potential roles under high-temperature stress, we performed a comprehensive identification of the SOD gene family in the low-latitude cultivar 'Hang Baishao' and analyzed the expression patterns of SOD family genes (PlSODs) in response to high-temperature stress and exogenous hormones. The present study identified ten potential PlSOD genes, encoding 145-261 amino acids, and their molecular weights varied from 15.319 to 29.973 kDa. Phylogenetic analysis indicated that PlSOD genes were categorized into three sub-families, and members within each sub-family exhibited similar conserved motifs. Gene expression analysis suggested that SOD genes were highly expressed in leaves, stems, and dormancy buds. Moreover, RNA-seq data revealed that PlCSD1-1, PlCSD3, and PlFSD1 may be related to high-temperature stress response. Finally, based on the Quantitative Real-time PCR (qRT-PCR) results, seven SOD genes were significantly upregulated in response to high-temperature stress, and exogenous EBR and ABA treatments can enhance high-temperature tolerance in P. lactiflora. Overall, these discoveries lay the foundation for elucidating the function of PlSOD genes for the thermotolerance of herbaceous peony and facilitating the genetic breeding of herbaceous peony cultivars with strong high-temperature resistance.

Enrichment and characterization of thermophilic anaerobic ammonium oxidizing bacteria from hot spring.

Anaerobic ammonium oxidization (Anammox) process plays a crucial role in the global nitrogen cycle and sustainable biological nitrogen removal from wastewater. Although Anammox bacteria have been detected across mesophilic and thermophilic conditions, the direct cultivation of Anammox bacteria from thermal environments has remained elusive. This impedes limiting our understanding of their physiology and ecology in high-temperature habitats. Here, we successfully enriched Anammox bacteria from hot spring sediments at 45 °C, achieving an ammonium oxidation rate of 158.0 mg NH4+-N l-1d-1, with the genus 'Candidatus Brocadia' presenting 22.9 % of the total microbial community after about 500 days of operation. Metagenomic analysis recovered two high-quality genomes of novel Anammox bacteria, which we designed as 'Candidatus Brocadia thermophilus' and 'Candidatus Brocadia thermoanammoxidans'. Both of them encoded and actively expressed key metabolic genes involved in Anammox process and several genes associated with thermotolerance, demonstrating their remarkable ability to perform Anammox reaction in thermophilic environments. Notably, phylotypes related to 'Candidatus Brocadia thermoanammoxidans' have frequently been retrieved from geographically distinct natural habitats. These findings expand our understanding of thermophilic Anammox bacteria and underscore their potential in the nitrogen cycle of thermal natural and engineering ecosystems.

Heat stress induces a three-phase thermoregulatory response in different hot and humid environments in rats.

As global warming intensifies, heat waves occur more frequently around the world. Heat stress from hot and humid environments poses a significant threat to human health. It can cause a significant increase in core body temperature (CBT), and even lead to life-threatening heat stroke. Extremely high CBT is considered the most important clinical symptom and prognostic indicator of heat stroke. To study it, we implanted temperature-monitoring capsules into the abdominal cavities of rats to measure their CBT values. The rats were then exposed to different hot and humid environments to monitor the resultant changes in their CBTs. The results showed that heat stress could induce a three-phase thermoregulatory response in rats under different conditions. A temperature plateau was observed as part of the three-phase thermoregulatory response, at a similar CBT across different conditions. The duration of this plateau can reflect the thermotolerance of rats in hot and humid environments. The third stage of the three-phase thermoregulatory response reflects the pathogenesis of heat stroke, which may present the key stage of heat injury. Moreover, a certain range of humidity did not affect the thermoregulatory responses of rats, but exerted a significant impact once a certain threshold was reached. In this study, the CBTs of the rats in different environments were monitored to characterize their thermoregulatory responses under heat stress. In particular, the discovery of the plateau phase and humidity threshold may help to better understand the effects of high temperature and humidity conditions on living organisms.

Hyperthermia and radiotherapy: physiological basis for a synergistic effect.

In cancer treatment, mild hyperthermia (HT) represents an old, but recently revived opportunity to increase the efficacy of radiotherapy (RT) without increasing side effects, thereby widening the therapeutic window. HT disrupts cellular homeostasis by acting on multiple targets, and its combination with RT produces synergistic antitumoral effects on specific pathophysiological mechanisms, associated to DNA damage and repair, hypoxia, stemness and immunostimulation. HT is furthermore associated to direct tumor cell kill, particularly in higher temperature levels. A phenomenon of temporary resistance to heat, known as thermotolerance, follows each HT session. Cancer treatment requires innovative concepts and combinations to be tested but, for a meaningful development of clinical trials, the understanding of the underlying mechanisms of the tested modalities is essential. In this mini-review, we aimed to describe the synergistic effects of the combination of HT with RT as well as the phenomena of thermal shock and thermotolerance, in order to stimulate clinicians in new, clinically relevant concepts and combinations, which become particularly relevant in the era of technological advents in both modalities but also cancer immunotherapy.

Molecular dialogue between light and temperature signaling in plants: From perception to thermotolerance.

Light and temperature are the two most variable environmental signals, which significantly regulate plant growth and development. Plants in the natural environment usually encounter warmer temperatures during the day and cooler temperatures at night, suggesting both light and temperature are closely linked signals. Due to global warming, it has become important to understand how light and temperature signaling pathways converge, and regulate plant development. This review outlines diverse mechanisms of light and temperature perception and downstream signaling, with an emphasis on their integration and interconnection. The recent research has highlighted the regulation of thermomorphogenesis by photoreceptors and their downstream light signaling proteins under different light conditions, and circadian clock components at warm temperatures. We have made an attempt to comprehensively describe these studies and demonstrate their connection with plant developmental responses. We have also explained how gene signaling pathways of light and thermomorphogenesis, are interconnected with HSR-mediated thermotolerance, which reveals new avenues to manipulate plants for climate resilience. In addition, the role of sugars as signaling molecules between light and temperature is also highlighted. Thus, we envisage that such detailed knowledge will enhance the understanding of how plants perceive light and temperature cues simultaneously and bring about responses that help in their adaptation.

LzSCL9, a Novel GRAS Transcription Factor in Lanzhou Lily (Lilium davidii var. unicolor), Participates in Regulation of Trichokonins-Primed Heat Stress Tolerance.

In our previous research, we found that trichokonins' (TKs) employment improved the thermotolerance of the Lanzhou lily, a renowned edible crop species endemic to China that is relatively susceptible to high temperatures (HTs). Here, a novel Lanzhou lily GRAS gene, LzSCL9, was identified to respond to heat stress (HS) and HS+TKs treatment based on transcriptome and RT-qPCR analysis. TKs could improve the upregulation of LzSCL9 during long-term HS. The expression profile of LzSCL9 in response to HS with or without TKs treatment showed a significant positive correlation with LzHsfA2a-1, which was previously identified as a key regulator in TKs' conferred resilience to HT. More importantly, overexpression of LzSCL9 in the lily enhanced its tolerance to HTs and silencing LzSCL9 in the lily reduced heat resistance. Taken together, this study identified the positive role of LzSCL9 in TK-induced thermotolerance, thereby preliminarily establishing a molecular mechanism on TKs regulating the thermostability of the Lanzhou lily and providing a new candidate regulator for plant heat-resistant breeding.

Characterization of susceptibility patterns and adaptability of the newly emerged Candida auris.

The emergence of Candida auris has caused a major concern in the public health worldwide. This novel fungus is characterized by its multidrug resistance profile, ability to thrive in harsh and stressful conditions, as well as high temperatures and salt concentrations, persistence on hospital surfaces, causing nosocomial infections and outbreaks, and unique fitness properties. Here, we study the antifungal susceptibility patterns, thermotolerance, and halotolerance of 15 putative C. auris clinical isolates from Inkosi Albert Academic Hospital, Durban, South Africa. Five of the C. auris isolates showed resistance to all three antifungals (fluconazole, amphotericin B, and micafungin) and were selected for characterization of their adaptability mechanisms. Four of the tested multidrug-resistant C. auris isolates (C. auris strain F25, C. auris strain F276, C. auris F283, and C. auris M153) showed good growth when exposed to high temperature (42 °C) and salinity (10% NaCl) conditions whereas one isolate (C. auris F65) showed moderate growth under these conditions. Candida parapsilosis showed poor growth whereas C. albicans no growth under these conditions. The five C. auris strains were positive for all the adaptive features.

Consequences of gene editing of PRLR on thermotolerance, growth, and male reproduction in cattle.

Global warming is a major challenge to the sustainable and humane production of food because of the increased risk of livestock to heat stress. Here, the example of the prolactin receptor (PRLR) gene is used to demonstrate how gene editing can increase the resistance of cattle to heat stress by the introduction of mutations conferring thermotolerance. Several cattle populations in South and Central America possess natural mutations in PRLR that result in affected animals having short hair and being thermotolerant. CRISPR/Cas9 technology was used to introduce variants of PRLR in two thermosensitive breeds of cattle - Angus and Jersey. Gene-edited animals exhibited superior ability to regulate vaginal temperature (heifers) and rectal temperature (bulls) compared to animals that were not gene-edited. Moreover, gene-edited animals exhibited superior growth characteristics and had larger scrotal circumference. There was no evidence for deleterious effects of the mutation on carcass characteristics or male reproductive function. These results indicate the potential for reducing heat stress in relevant environments to enhance cattle productivity.

Proteomic changes of the bovine blood plasma in response to heat stress in a tropically adapted cattle breed.

Background: Identifying molecular mechanisms responsible for the response to heat stress is essential to increase production, reproduction, health, and welfare. This study aimed to identify early biological responses and potential biomarkers involved in the response to heat stress and animal's recovery in tropically adapted beef cattle through proteomic analysis of blood plasma. Methods: Blood samples were collected from 14 Caracu males during the heat stress peak (HSP) and 16 h after it (heat stress recovery-HSR) assessed based on wet bulb globe temperature index and rectal temperature. Proteome was investigated by liquid chromatography-tandem mass spectrometry from plasma samples, and the differentially regulated proteins were evaluated by functional enrichment analysis using DAVID tool. The protein-protein interaction network was evaluated by STRING tool. Results: A total of 1,550 proteins were detected in both time points, of which 84 and 65 were downregulated and upregulated during HSR, respectively. Among the differentially regulated proteins with the highest absolute log-fold change values, those encoded by the GABBR1, EPHA2, DUSP5, MUC2, DGCR8, MAP2K7, ADRA1A, CXADR, TOPBP1, and NEB genes were highlighted as potential biomarkers because of their roles in response to heat stress. The functional enrichment analysis revealed that 65 Gene Ontology terms and 34 pathways were significant (P < 0.05). We highlighted those that could be associated with the response to heat stress, such as those related to the immune system, complement system, hemostasis, calcium, ECM-receptor interaction, and PI3K-Akt and MAPK signaling pathways. In addition, the protein-protein interaction network analysis revealed several complement and coagulation proteins and acute-phase proteins as important nodes based on their centrality and edges. Conclusion: Identifying differentially regulated proteins and their relationship, as well as their roles in key pathways contribute to improve the knowledge of the mechanisms behind the response to heat stress in naturally adapted cattle breeds. In addition, proteins highlighted herein are potential biomarkers involved in the early response and recovery from heat stress in tropically adapted beef cattle.

Effects of high temperature on the growth performance and midgut autophagy of thermotolerant and thermosensitive silkworm strains.

High temperature stress has long-term negative effects on the growth and development of silkworm (Bombyx mori). Different silkworm varieties show the different tolerance to high temperature. The induction of autophagy is linked to increased thermotolerance in diverse ectothermic organisms. However, the function of autophagy in the thermotolerant and thermosensitive silkworm strains under high-temperature conditions remains unclear. The thermotolerant Liangguang NO.2 and thermosensitive Jingsong × Haoyue strains were used to explore the role of autophagy in thermotolerance. Here, we first found that the larval body weight gain was increased in the thermosensitive Jingsong × Haoyue strain, but there was no difference in the thermotolerant Liangguang NO.2 strain under high temperature conditions. High temperature stress had a negative influence on the cocoon performance in both the Liangguang NO.2 and Jingsong × Haoyue strains. Additionally, the autophagy-related gene Atg5 mRNA expression in the Liangguang NO.2 strain was upregulated by high temperature, while the expression of Atg12 mRNA was reduced in the Jingsong × Haoyue strain. Titers of 20-Hydroxyecdysone and the ultraspiracle 1 mRNA expression in the Liangguang NO.2 strain were upregulated by high temperature, which might be associated with the induction of autophagy. These results demonstrate the potentially regulatory mechanism of autophagy in silkworms' tolerance to high temperature, providing a theoretical basis for exploring the physiological mechanism of thermotolerance in insects.

A high-quality genome assembly reveals adaptations underlying glossy, wax-coated leaves in the heat-tolerant wild raspberry Rubus leucanthus.

With glossy, wax-coated leaves, Rubus leucanthus is one of the few heat-tolerant wild raspberry trees. To ascertain the underlying mechanism of heat tolerance, we generated a high-quality genome assembly with a genome size of 230.9 Mb and 24,918 protein-coding genes. Significantly expanded gene families were enriched in the flavonoid biosynthesis pathway and the circadian rhythm-plant pathway, enabling survival in subtropical areas by accumulating protective flavonoids and modifying photoperiodic responses. In contrast, plant-pathogen interaction and MAPK signaling involved in response to pathogens were significantly contracted. The well-known heat response elements (HSP70, HSP90, and HSFs) were reduced in R. leucanthus compared to two other heat-intolerant species, R. chingii and R. occidentalis, with transcriptome profiles further demonstrating their dispensable roles in heat stress response. At the same time, three significantly positively selected genes in the pathway of cuticular wax biosynthesis were identified, and may contribute to the glossy, wax-coated leaves of R. leucanthus. The thick, leathery, waxy leaves protect R. leucanthus against pathogens and herbivores, supported by the reduced R gene repertoire in R. leucanthus (355) compared to R. chingii (376) and R. occidentalis (449). Our study provides some insights into adaptive divergence between R. leucanthus and other raspberry species on heat tolerance.

Heat stress transcription factors as the central molecular rheostat to optimize plant survival and recovery from heat stress.

Heat stress transcription factors (HSFs) are the core regulators of the heat stress (HS) response in plants. HSFs are considered as a molecular rheostat: their activities define the response intensity, incorporating information about the environmental temperature through a network of partner proteins. A prompted activation of HSFs is required for survival, for example the de novo synthesis of heat shock proteins. Furthermore, a timely attenuation of the stress response is necessary for the restoration of cellular functions and recovery from stress. In an ever-changing environment, the balance between thermotolerance and developmental processes such as reproductive fitness highlights the importance of a tightly tuned response. In many cases, the response is described as an ON/OFF mode, while in reality, it is very dynamic. This review compiles recent findings to update existing models about the HSF-regulated HS response and address two timely questions: How do plants adjust the intensity of cellular HS response corresponding to the temperature they experience? How does this adjustment contribute to the fine-tuning of the HS and developmental networks? Understanding these processes is crucial not only for enhancing our basic understanding of plant biology but also for developing strategies to improve crop resilience and productivity under stressful conditions.

Early life thermal conditioning alters heat-shock protein expression in response to an adult thermal stressor.

Developmental environmental stressors can have instructive effects on an organism's phenotype. This developmental plasticity can prepare organisms for potentially stressful future environments, circumventing detrimental effects on fitness. However, the physiological mechanisms underlying such adaptive plasticity are understudied, especially in vertebrates. We hypothesized that captive male zebra finches (Taeniopygia castanotis) exposed to a mild heat conditioning during development would acquire a persisting thermotolerance, and exhibit increased heat-shock protein (HSP) levels associated with a decrease in oxidative damage when exposed to a high-intensity stressor in adulthood. To test this, we exposed male finches to a prolonged mild heat conditioning (38°C) or control (22°C) treatment as juveniles. Then in a 2 × 2 factorial manner, these finches were exposed to a high heat stressor (42°C) or control (22°C) treatment as adults. Following the adult treatment, we collected testes and liver tissue and measured HSP70, HSP90, and HSP60 protein levels. In the testes, finches exhibited lower levels of HSP90 and HSP60 when exposed to the high heat stressor in adulthood if they were exposed to the mild heat conditioning as juveniles. In the liver, finches exposed to the high heat stressor in adulthood had reduced HSP90 and HSP60 levels, regardless of whether they were conditioned as juveniles. In some cases, elevated testes HSP60 levels were associated with increased liver oxidative damage and diminishment of a condition-dependent trait, indicating potential stress-induced tradeoffs. Our results indicate that a mild conditioning during development can have persisting effects on HSP expression and acquired thermotolerance.

HSFA1 heat shock factors integrate warm temperature and heat signals in plants.

Warm temperatures and heat stress trigger distinct plant responses. Recently, Li et al. and Tan et al. identified HSFA1 heat shock transcription factors (HSFs) as central gatekeepers of high-temperature signaling, integrating warm temperature and heat shock responses (HSRs) in arabidopsis (Arabidopsis thaliana). HSFA1d stabilizes phytochrome-interacting factor 4 (PIF4) and activates HSFA2, establishing a crosstalk between thermomorphogenesis and thermotolerance.

Impact of thermal manipulation during embryogenesis on thermotolerance and semen quality of Mandarah roosters exposed to heat stress.

Background and Aim: The management of incubation conditions impacts embryonic development, hatchability, and post-hatch performance. This study aimed to examine the effects of thermal manipulation (TM) during embryonic development on roosters' thermotolerance, antioxidant activity, immunity, and semen quality under heat-stress conditions. Materials and Methods: 1200 fertile eggs were distributed evenly between two groups, each containing three replicates (200 eggs/replicate). The first group (G1) was held in the commercial setter with a consistent temperature of 37.5°C and 55% relative humidity (RH) through the 18-day incubation period, acting as a control, while the second group (G2) experienced these conditions until only the 11th day. The eggs were incubated at 39.5°C with 60% RH for 4 h each day from the 12th to the 18th day. From the 19th to 22nd incubation days, both groups maintained a consistent temperature of 37.2°C with a RH of 70%. Two hundred hatched male chicks per treatment group were moved into a closed-system house. All roosters were exposed to a 6-h daily heat challenge with a temperature of 35°C and a humidity of 70% between their 36th and 40th weeks of age. Results: Roosters of G2 exposed to thermal challenge showed improvements (p ≤ 0.05) in multiple blood biochemical, antioxidant, and immunity markers, including total protein, globulin, aspartate aminotransferase, alanine aminotransferase, triiodothyronine, thyroxine, corticosterone, testosterone, total antioxidant capacity, malondialdehyde, immunoglobulin G, immunoglobulin M, and immunoglobulin A levels. Improved semen quality characteristics, including ejaculate volume, sperm concentration, motility, livability, and quality factor, as well as enhanced thermoregulation in post-hatch cocks, were also achieved (p ≤ 0.05). Conclusion: To boost antioxidant activity, immunity, thermotolerance, and semen parameters in roosters under heat-stress conditions, TM application during egg incubation, specifically at 12-18 days, is recommended.

Transgenic tobacco plants overexpressing a wheat salt stress root protein (TaSSRP) exhibit enhanced tolerance to heat stress.

BACKGROUND: Heat stress is a detrimental abiotic stress that limits the development of many plant species and is linked to a variety of cellular and physiological problems. Heat stress affects membrane fluidity, which leads to negative effects on cell permeability and ion transport. Research reveals that heat stress causes severe damage to cells and leads to rapid accumulation of reactive oxygen species (ROS), which could cause programmed cell death. METHODS AND RESULTS: This current study aimed to validate the role of Triticum aestivum Salt Stress Root Protein (TaSSRP) in plants' tolerance to heat stress by modulating its expression in tobacco plants. The Relative Water Content (RWC), total chlorophyll content, and Membrane Stability Index (MSI) of the seven distinct transgenic lines (T0 - 2, T0 - 3, T0 - 6, T0 - 8, T0 - 9, T0 - 11, and T0 - 13), increased in response to heat stress. Despite the fact that the same tendency was detected in wild-type (WT) plants, changes in physio-biochemical parameters were greater in transgenic lines than in WT plants. The expression analysis revealed that the transgene TaSSRP expressed from 1.00 to 1.809 folds in different lines in the transgenic tobacco plants. The gene TaSSRP offered resistance to heat stress in Nicotiana tabacum, according to the results of the study. CONCLUSION: These findings could help to improve our knowledge and understanding of the mechanism underlying thermotolerance in wheat, and the novel identified gene TaSSRP could be used in generating wheat varieties with enhanced tolerance to heat stress.