Can silicate types regulate plant defense and rhizospheric microbiome diversity differently during heat stress conditions?

Heat stress is a major environmental challenge affecting agricultural productivity and food security. The jasmonate (JA)-myelocytomatosis protein 2 (MYC2) pathway plays a critical role in plant growth and stress response. However, the mechanisms of how the JA-MYC2 pathway participates in the heat stress response in tomato remain unclear. Here, using approaches of reverse genetics, biochemical and molecular biology, we explore the molecular mechanism by which the JA signaling pathway and the histone demethylase Jumonji C domain - containing protein C3 (JMJC3)synergistically regulate thermotolerance in tomato. The JA biosynthetic mutant spr2 exhibited reduced thermotolerance, which was rescued by exogenous methyl jasmonate. Further analysis revealed that the transcription factor MYC2, a key JA signaling component, directly binds to the promoters of heat shock proteins (HSPs), activating their expression under heat stress. Moreover, MYC2 interacts with the histone demethylase JMJC3, which specifically removes repressive histone marks (H3K9me1/3 and H3K27me3) at HSP loci, facilitating their transcription. Genetic evidence showed that JMJC3 silencing compromises MYC2-mediated thermotolerance and HSP induction. Notably, MYC2 also transcriptionally activates JMJC3, forming a positive feedback loop. Collectively, the study unveiled a JA-MYC2-JMJC3 module that integrates hormonal signaling and epigenetic regulation to enhance HSP expression and thermotolerance in tomato, providing insights into plant adaptation to heat stress.

Climate change, especially terminal heat stress, poses a major threat to wheat production by affecting both crop establishment and grain quality. Developing climate-resilient cultivars requires identifying genotypes that can maintain stable seed Vigour and grain quality under different thermal conditions. Therefore, it is necessary to evaluate the genetic stability of these key traits in diverse wheat genotypes to identify promising lines for breeding heat-resilient varieties. This study aimed to assess the genetic stability of seed Vigour and grain quality parameters in 43 diverse wheat genotypes. Laboratory experiments were conducted on seeds produced under two contrasting field environments: a temperate condition (E1: 2023-24) and a heat-stress condition (E2: 2024-25). Analysis of variance revealed highly significant (P less than 0.01) genotypic differences for all ten evaluated traits, confirming substantial genetic variability. The heat-stress environment generally compromised seed performance, significantly reducing mean germination to 85.09% and seedling dry weight to 0.16 g, while notably increasing mean grain protein content to 12.69%. Among the genotypes, WH 1182 demonstrated superior stability with one of the highest Seed Vigour Index-I values (3548.75) under stress. PBW 750 excelled in biomass accumulation, achieving the highest seedling dry weight (0.49 g) and Seed Vigour Index-II (46.17) in the stress environment. Furthermore, HD 2307 proved genetically stable for grain quality, maintaining the highest protein content (15.90%) under heat stress conditions.

The biogenesis of mitochondria relies on the import of newly synthesized precursor proteins from the cytosol. Tom70 is a mitochondrial surface receptor which recognizes precursors and serves as an interface between mitochondrial protein import and the cytosolic proteostasis network. Mitochondrial import defects trigger a complex stress response, in which compromised protein synthesis rates are a characteristic element. The molecular interplay that connects mitochondrial (dys)function to cytosolic translation rates in yeast cells is however poorly understood. Here, we show that the deletion of the two Tom70 paralogs of yeast (TOM70 and TOM71) leads to defects in mitochondrial biogenesis and slow cell growth. Surprisingly, upon heat stress, the deletion of ZUO1, a chaperone of the ribosome-associated complex (RAC), largely prevented the slow growth and the reduced translation rates in the tom70Δ/tom71Δ double deletion mutant. In contrast, the mitochondrial defects were not cured but even enhanced by ZUO1 deletion. Our study shows that Zuo1 is a critical component in the signaling pathway that mutes protein synthesis upon mitochondrial dysfunction. We propose a novel paradigm according to which RAC serves as a stress-controlled regulatory element of the cytosolic translation machinery.

Blue light strongly influences plant development, but its interaction with ethylene, a seed conditioning agent for abiotic stress tolerance, is poorly understood, especially for Moringa oleifera, a crucial crop in arid regions. This study aimed to evaluate whether conditioning seeds with blue light (PB) or a combination of blue light and ethylene (PBE) could mitigate the adverse physiological and biochemical effects of water deficit and high temperature in M. oleifera seedlings. We used a 2 × 2 × 3 factorial design (water level, temperature, conditioning). Combined water and heat stress significantly impaired gas exchange, photochemical efficiency, osmotic adjustment, and biomass accumulation. However, seedlings from seeds conditioned with PB showed significant tolerance. The biological mechanism underlying this resilience was associated with the maintenance of higher antioxidant activity (CAT in leaves, TSP in roots) and greater water use efficiency (WUE) in seedlings conditioned with PBE. Under moderate drought conditions (water stress without heat), conditioning with blue light alone (PB) was more effective, increasing carboxylation efficiency. Although all abiotic stresses increased cell membrane damage (electrolyte leakage), treatment with ethylene (PBE) mitigated the most severe damage by pre-activating these protective pathways. Conditioning seeds with a combination of blue light and ethylene (PBE) is a promising strategy to enhance Moringa oleifera's resilience to moderate drought by modulating antioxidant and photosynthetic pathways. However, the effectiveness of this conditioning decreased under severe combined heat and drought conditions, indicating a critical limitation of the treatment under extreme stress.Keywords: Moringaceae; Abiotic stresses; plant hormones; light spectrum; osmotic adjustment; antioxidant mechanism.

This study is a systematic review of heat stress-driven changes in tomato morphology and physiology, thermotolerance mechanisms, and crop improvement methods. Tomato is a widely cultivated and utilized crop. However, climate change poses a direct threat to food systems by diminishing the productivity and indirectly limiting the genetic diversity of crops and their wild relatives. Consequently, this limits future options for breeding improved varieties and makes it harder to adapt crops to new challenges. This is particularly concerning as the average global surface temperature is anticipated to increase by 0.3°C over the next 10years. Because of their sessile nature, tomato plants have developed complex signalling networks that allow them to detect changes in ambient temperature. However, high-temperature stress can negatively impact the morphology, physiology, and biochemistry of tomato plants at every stage of development, from vegetative to reproductive. This heat stress leads to significant yield losses due to induced changes in crop phenology, growth patterns, sensitivity to pests, shrinkage of the maturity period, and accelerated senescence. Finding novel sources of heat tolerance and identifying the genes involved in those pathways have become significant challenges in the modern era due to global warming. This complexity is further increased by significant genotype-environment and epistatic interactions, making it difficult for breeders to develop and select heat-tolerant genotypes. The current review aims to provide insights into physiological processes related to heat stress, the molecular underpinnings of tomato heat tolerance, germplasm and quantitative trait loci governing tolerance, and the different crop improvement techniques utilized in breeding for heat tolerance of tomato. Deciphering various physiological processes and the development of different breeding techniques are critical to assist in the evolution of thermotolerant tomato cultivars.

Urban microclimates result from complex interactions between buildings, vegetation, and human activities, impacting energy consumption, air quality, and urban planning. Understanding and mapping these microclimates is essential for sustainable city development. Geographic Information Systems (GIS) play a crucial role in analyzing microclimate patterns by integrating spatial datasets such as land cover, building heights, and meteorological data. This study examines urban microclimates in İzmir's Konak District using GIS and unmanned aerial vehicles (UAVs) equipped with thermal sensors. By classifying Local Climate Zones (LCZs) and analyzing their relationship with land surface temperatures (LSTs), the research highlights how urban morphology shapes microclimatic conditions. The study area was divided into 2,435 grids, with UAV-based thermal imaging providing high-resolution temperature data. Findings indicate that LCZs with high impermeable surface fractions (e.g., LCZ 7, LCZ 8, and LCZ E) exhibited elevated temperatures, while vegetated or water-rich zones (e.g., LCZ B and LCZ G) demonstrated cooling effects. The Heat Load Map identified 8.8% of the district as experiencing excessive heat, while 21.7% benefited from optimal thermal conditions due to green and blue spaces. This study underscores the importance of increasing vegetation and permeable surfaces to mitigate urban heat islands (UHIs). By integrating UAV technology with GIS, it advances LCZ-based urban climate research and provides practical tools for climate-responsive planning. Understanding microclimates in dense urban areas enables targeted strategies to reduce heat stress, improve air quality, and enhance urban livability.

Silvopastoral system as a strategy to mitigate heat stress in sheep in the Brazilian semi-arid region

Forage maize is a central pillar of dairy cow feeding in France, directly influencing milk production. Drought significantly affects both maize yield and digestibility, which are both key parameters required for hybrid registration purposes. Research on maize inbred lines has revealed droughts’ notable effect on dry matter and cell wall digestibilities due to changes in cell wall composition, directly impacting forage quality. No such studies have been performed on forage maize hybrids however, which are the main seed type used in the agricultural sector. In this paper, we aimed to understand the impact of water and heat stress on forage maize digestibility, and to uncover the factors controlling it. We grew a panel of eleven modern forage maize hybrids for two years under four different controlled water stress modalities. These plants were agronomically, biochemically and histologically assayed, allowing us to perform a multiscale analysis to determine the traits responsible for variations in digestibility. By establishing a comprehensive heat and water stress index, we classified the environmental conditions. We demonstrated that under severe stress, ear production decreases significantly, but dry matter digestibility can be maintained through increased cell wall digestibility. This boost in cell wall digestibility was due to a reduction in p-hydroxycinnamic acid content and changes in lignin distribution, while lignin content and structure remained stable. The significant impact of lignin distribution on cell wall digestibility increased with the severity of the stress, reaching an extreme threshold where biochemical parameters solely account for digestibility variations. To improve maize digestibility, it will be necessary to better understand how the reduction in carbon flux under stress affects p-hydroxycinnamic acid levels without greatly impacting lignin content. Finally, our work suggests that the inclusion of moderate stress conditions in future maize breeding programs will be necessary to better adapt forage maize hybrids to climate change.

The interaction between host microbiomes, pathogen diversity, and environmental stress is a critical but understudied mechanism shaping disease outcomes in marine foundation species. Eelgrass (Zostera marina) suffering from wasting disease, caused by the protist Labyrinthula zosterae, offers a powerful system with which to probe this interaction. We conducted complementary laboratory experimentation and field surveys to examine three main questions: (1) whether thermal stress compromises the eelgrass microbiome and exacerbates disease outcomes; (2) whether different isolates of L. zosterae differ in virulence and their effects on the host microbiome; and (3) whether laboratory-derived microbiome signatures of heat stress correspond with those observed in the field. In the lab, we exposed eelgrass pieces to two temperature regimes (11°C vs. 19°C) and inoculated with two L. zosterae strains. We tracked lesion development, pathogen load via qPCR, and epiphytic microbiome dynamics via 16S rRNA gene sequencing. In parallel, we tagged and sampled intact intertidal eelgrass in situ at Fourth of July Beach, San Juan Island, Washington, before and after a three-day heat stress event, tracking tissue damage, growth, and microbiome dynamics. In the lab, elevated temperature significantly heightened wasting disease severity across both pathogen isolates, with no significant difference in virulence between them. High temperatures in the lab also led to more pronounced diseased-induced microbiome dysbiosis: community composition shifted, and a greater number of microbial taxa changed in abundance relative to controls, including Colwelliaceae. Both lab and field heat stress decreased microbiome diversity with intertidal eelgrass experiencing extensive tissue damage and reduced growth. Warming accelerates wasting disease progression in Z. marina by some combination of microbiome disruption, enhanced pathogen virulence, or compromised host defenses. Although pathogen strain identity had limited influence, temperature emerged as a dominant driver of both disease outcomes and microbiome shifts. While temperature stress in the lab and field was not comparable in duration and intensity, we show consistent trends towards microbiome dysbiosis characterized by changes in diversity and taxon abundance. Exploring the four-way interaction among host, microbiome, pathogen, and environment promises deeper insights for forecasting disease outbreaks and bolstering resilience in eelgrass ecosystems.

Brassica napus L. (rapeseed) represents one of the world's most important oilseed crops, yet its yield is increasingly impacted by heat-a threat that is intensifying under climate change. Here, we employed an integrative framework combining RNA‑Seq meta‑analysis, weighted gene co‑expression network analysis (WGCNA), and gene regulatory network (GRN) inference to dissect the transcriptional programs activated during the response of rapeseed to heat stress. WGCNA partitioned the transcriptome into three principal modules-green, black, and brown-with genes in the black and brown modules exhibiting predominantly decreased expression under heat, whereas the green module was largely characterized by upregulation. The green module promoted energy conservation, transcriptome flexibility through alternative splicing, endoplasmic reticulum remodeling, proteostasis via chaperone activity, redox balance, and reduced ABA sensitivity to enhance transpirational cooling. In contrast, the black and brown modules, largely downregulated, restricted carbon fixation, cyclic electron flow, chlorophyll turnover, and PSII repair while sustaining stomatal opening, highlighting a trade-off between photosynthetic efficiency and thermotolerance. Within GRNs, upregulated hub TFs reinforced chaperone function, ROS detoxification, (post-)transcriptional reprogramming, and photosynthetic support whereas downregulated hub TFs suppressed photosynthesis, metabolism, growth, transport, and basal immunity thereby redirecting resources toward essential heat stress responses. Our results illuminate the key regulatory mechanisms and co‑expressed gene clusters that orchestrate adaptive response of rapeseed to heat, offering valuable molecular targets for the development of varieties with improved tolerance to heat stress conditions.

ABSTRACTThis study aims to explore the effects of resveratrol on the NLRP3 inflammasome and its regulatory mechanism in the liver of heat‐stressed broilers. Broilers were randomly divided into three groups: (1) Control (23°C ± 2°C), (2) Heat stress (HS, 35°C ± 2°C, 8 h/day), and (3) Resveratrol (HS + resveratrol) group. Resveratrol supplementation (400 mg/kg diet) commenced 48 h prior to HS and continued throughout the experimental period. The results showed that resveratrol improved growth performance with a higher average daily gain (ADG) and lower feed conversion ratio (FCR), and increased liver weight and index along with reduced inflammatory cell infiltration in broilers. In addition, resveratrol upregulated the autophagy‐related genes and protein levels in the liver. Moreover, resveratrol obviously down‐regulated the protein and mRNA levels of the NOD‐like receptor protein 3 (NLRP3) inflammasome. In conclusion, resveratrol mitigated heat stress‐induced liver injury by modulating autophagy and down‐regulating NLRP3 inflammasome activation.

Prokaryotes use polycistronic transcription (operons) to express multiple messenger RNAs (mRNAs) from a single promoter to coexpress functionally related genes. However, how do eukaryotes, which express monocistronic messages, achieve the same regulation? Previously, we demonstrated that yeast uses RNA operons, i.e., mRNAs assembled in trans (transperons), to control multiple cellular pathways such as the heat shock response (HSR). As the HSR is conserved from yeast to mammals, we used single-molecule RNA labeling and pulldown techniques to demonstrate that mammalian heat shock protein (HSP) mRNAs also form operons upon transcription during heat stress. HSP RNA operon formation is dependent on the heat shock factor 1 transcription factor and intra- and interchromosomal interactions between the HSP genes. Work in yeast identified a conserved RNA sequence motif and histone H4 functions that act downstream thereof to regulate transperon assembly. Our work highlights the evolutionarily conserved regulation of the HSR and for RNA operons in eukaryotic gene regulation.

Cultivated crops are increasingly exposed to episodes of extreme heat. In the Mediterranean basin, crops often experience heat stress during spring or summer, coinciding with flowering and seed ripening. Recently, Camelina sativa has emerged as an alternative oilseed crop of interest due to its resistance to abiotic stresses. To investigate possible mechanisms underlying camelina’s ability to cope with heat stress and to evaluate the role of tocopherols, two spring varieties (Cypress and Omega) were tested in two controlled-environment experiments. Heat was imposed for five consecutive days either from the end of flowering (EXP1) or from the stage when siliques reached their final size (EXP2). Early imposition of heat stress (EXP1) had the greatest impact on camelina morphological parameters during the growth cycle. At harvest in EXP1, only the genotype significantly affected plant height and seed yield, with Omega producing taller plants and higher seed yield (0.83 g per plant) compared with Cypress (0.70 g per plant). In EXP2, cultivar significantly affected only straw weight, which was higher in Omega. Nonetheless, Cypress exhibited the highest 1,000-seed weight in both experiments (1.36 g in EXP1 and 1.34 g in EXP2). Seed oil content was reduced by heat stress (− 9.89% in EXP1 and − 11.6% in EXP2, respectively). Fatty acid composition in EXP1 was mainly influenced by the cultivar, except for C18:1, whereas in EXP2, heat stress predominantly affected 18-carbon fatty acids. Total tocopherol content was largely under genetic control, and although α-tocopherol is associated with responses to abiotic stress, it increased only when stress was imposed at a later stage (+ 75.8% in the stressed plants). Despite the high tocopherol content of camelina, it appeared to contribute to plant stress resistance only under late-stage heat stress dueing seed maturation.

Global temperature rise increasingly exposes domestic dogs ( Canis lupus familiaris ) to thermal challenges, especially in tropical and urban regions where climate change, artificial structures, and inadequate care converge. Despite the species’ adaptive capacity, morphological traits such as dense coats, brachycephalic conformation, and obesity reduce thermoregulatory efficiency, heightening the risk of heat stress. This review synthesizes evidence on physiological heat exchange mechanisms, discusses subclinical indicators of thermal overload, and presents preventive management strategies tailored to breed profiles and environmental contexts. Emerging technologies, such as wearable thermal sensors, and educational actions targeting caregivers and professionals are explored as tools to promote adaptive care. By adopting a One Welfare perspective, the article connects animal welfare, public health, and sustainability, contributing to professional, policy, and educational practices aimed at protecting dogs from thermal stress in a warming world.

Urban densification in post-socialist cities has drastically reduced open and green spaces in high-rise housing areas (HRHAs), intensifying heat stress and degrading outdoor thermal comfort (OTC). These neighborhoods—shaped by socialist-era planning and, later, market-led infill—combine high built density, low greenery, and limited ventilation, making them critical testbeds for climate-adaptive regeneration. This study presents the first empirically validated ENVI-met assessment of blue–green infrastructure (BGI) performance in a post-socialist HRHA, using a representative courtyard in Niš, Serbia, during the 14 August 2024 heatwave. A 24 h field campaign (air temperature, humidity, wind speed, and mean radiant temperature) validated the model with high accuracy (R2 = 0.92, RMSE = 1.1 °C for air temperature; R2 = 0.88, RMSE = 3.5 K for Physiological Equivalent Temperature (PET). Four retrofit scenarios were simulated: S0 (existing), S1 (grass), S2 (grass + trees), and S3 (S2 + shallow pool). Across all scenarios, daytime PET indicated strong–extreme heat stress, peaking at 61.9 °C (16:00 h). The best configuration (S3) reduced PET by 2.68 °C (10:00 h) but <1 °C at peak hours, with acceptable comfort limited to 04:00–07:00 h. The results confirm that small-scale surface-level greening provides negligible thermal relief under a dense HRHA morphology. Urban morphological reform—optimizing height, spacing, ventilation, and integrated greening—is more effective for heat mitigation. Future work should include multi-seasonal field monitoring and human thermal-perception surveys to link microclimate improvement with exposure and health risk.

The primary role of the gastrointestinal tract in broiler chickens is nutrient assimilation, with transporter proteins facilitating the uptake of amino acids, peptides, monosaccharides, fatty acids, and minerals across the intestinal epithelium. Among these nutrient transporters, members of the solute carrier family are particularly important, and gene expression analyses targeting these transporters have provided informative insights into how birds adapt to diverse dietary, environmental, and physiological challenges to maintain nutrient homeostasis. These transporters are expressed either at the brush border membrane, where they facilitate the absorption of nutrients from the gut lumen into enterocytes, or at the basolateral membrane, where they mediate the transfer of nutrients from the enterocytes into the bloodstream. The expression of these transporters is influenced by a range of factors, including bird age, sex, intestinal segment, dietary substrate availability and source, as well as external stressors such as heat stress and pathogen exposure. While upregulation of transporter genes often suggests an enhanced capacity for nutrient uptake, it does not always correlate with improved growth performance, due to compensatory physiological responses and fluctuations in nutrient bioavailability. Understanding the regulation and functional dynamics of nutrient transporters presents valuable opportunities to develop targeted dietary and management strategies aimed at optimizing nutrient utilization and improving bird performance. This review summarizes current knowledge on the classification, function, and regulation of key nutrient transporters in broilers, highlights factors influencing their expression, and explores their implications for nutrition and production efficiency.

Perennial ryegrass (Lolium perenne) persistence and yield in many parts of New Zealand is critically reliant on its association with mutualistic fungal endophytes of the genus Epichloë. Epichloë spp. can protect their host plants from insect pests and improve tolerance to drought. Over the last 25 years several novel endophyte strains have been commercialised. While ensuring effective persistence of ryegrass, they have also minimised the negative impacts on livestock of ryegrass staggers, heat stress and productivity losses associated with the standard endophyte strain. A new endophyte product is becoming available – AR128. This Epichloë sp. LpTG-3 strain originated from Italy and has a similar known chemical profile to AR37, through expression of epoxyjanthitrems. AR128 protects the host ryegrass plant against the same insect pests as AR37. It also exhibits similar animal safety to that of AR37. However, AR128 transmits through seed production cycles at a greater frequency than AR37 and it also stores for a longer duration in seed at ambient temperature and humidity conditions. These features ensure that the end-user farmer obtains a high quality and effective product, which should ensure improved perennial ryegrass persistence and production compared to endophyte-free grasses and possibly other endophyte strains which are less amenable to transmission and storage. The human consumer of products derived from animals feeding on ryegrasses with AR128 can be assured that there are no food safety issues associated with this technology based on mouse feeding studies.

Due to global warming, temperate regions are increasingly experiencing heat waves, which negatively impact dairy cow welfare, productivity, and farm profitability. Ventilation systems (VSs) are a common heat mitigation strategy, despite their high initial investment cost. This study investigated the effects of heat stress (HS) and VSs on dairy cows’ milk yield and whether VSs guarantee an economic benefit for farmers. The trial involved four dairy farms over 3 years: 2 years before and one after VS installation. We conducted an observational within-farm pre-post study, using two pre-installation years and 0.5–1 post-installation year per farm. The following outcomes were analyzed at the herd level: daily milk yield, biweekly milk quality, and monthly reproductive metrics. The temperature-humidity index (THI) was calculated daily as a measure of HS and categorized as follows: comfort (<72), mild discomfort (72–79), discomfort (80–84), and alert (>84). Economic sustainability was assessed through partial budget analysis, accounting for additional feed, labor, and electricity costs. The presence of VSs was associated with a significant increase in cows’ milk yield across all THI conditions ( p < 0.001). Fat and protein contents decreased following VS installation, consistent with the observed increase in milk yield. However, their values were significantly lower under the most critical THI classes ( p < 0.001). Linear somatic cell count (SCC) scores were higher under the discomfort and alert THI classes in the absence of VSs, whereas they decreased slightly across THI classes when VSs were used ( p < 0.001). The duration of lactation, days open, and number of services per pregnancy reached their highest values under THI alert conditions in the absence of VSs and were significantly reduced following the implementation of VS ( p < 0.001). Increased milk income with VS use was €12.39/day/cow under mild discomfort, €12.23 under discomfort, and €12.08 under alert conditions. The results showed wide variability in economic outcomes across farms and THI classes. Although differences in VS management prevented a definitive conclusion regarding return on investment (ROI), the findings suggest positive effects on cows’ productivity and farm profitability. However, a definitive ROI could not be stated due to heterogeneity in fan size/spacing, cows-per-fan coverage, and farm-specific post-installation durations. Therefore, future cost–benefit analyses should consider additional factors to fully evaluate VS investments.

Abstract Understanding physiological responses to short-term changes in temperature is of growing interest considering the rising frequency and severity of transient temperatures such as heat waves. During the embryonic development of egg-laying vertebrates, inducible physiological responses to transient heat are likely critical to short-term survival but may also be energetically costly or disruptive to development. Inducible heat-shock proteins (HSPs) are conserved molecular chaperones which act to safeguard cellular protein homeostasis during transient stress. However, experiments in ectotherms have shown that overexpression of HSPs can increase embryonic mortality and reduce later thermotolerance. Yet, few studies have explored natural developmental patterns of HSP expression and heat inducibility in embryos of egg-laying ectothermic vertebrates. Using the red-eared slider turtle (Trachemys scripta), we characterized the response of five HSP genes in embryonic trunks following repeated 3-d transient heat wave exposures. Interestingly, we found that the expression of most HSPs naturally declined during early development and that warm temperatures amplified this decline, while also accelerating developmental rate. Only in a few instances did we observe induction of certain HSP genes during heat wave exposures, though this depended on the thermal history of the embryo. Specifically, induction of these genes during a particular heat wave was reduced in embryos that had already experienced two recent prior exposures relative to those experiencing it for the first or second time, suggesting repeated heat exposures can attenuate subsequent responses. The observed changes in HSP expression and inducibility may relate to an individual’s need to balance thermotolerance alongside extensive cellular differentiation and proliferation during early development. The effects of incubation temperature on these changes could also have important implications for how turtle embryos deal with subsequent heat stress and may be similarly present in other ectothermic vertebrates. Our study demonstrates the importance of considering ontogenetic changes in physiological responses to temperature even across embryonic development.