Heat Tolerance Research Articles

An alternating copolymer of phenothiazine and ethylenedioxythiophene for perovskite solar cells: effects of flexible and rigid substituent alternation.

Developing p-type polymeric semiconductors with exceptional electrical performance, heat tolerance, and cost-effectiveness is pivotal for advancing the practical application of n-i-p perovskite solar cells. Here, we employed direct arylation polycondensation to synthesize an alternating copolymer of phenothiazine and 3,4-ethylenedioxythiophene, featuring a high glass transition temperature (175 °C). In addition to the alternation of conjugated units within the main chain, the copolymer features alternating flexible (2-octyldodecyl) and rigid (trimethylphenyl) substituents at the nitrogen positions of the phenothiazine moiety. Compared to reference polymers with solely flexible or rigid substituents, the alternating use of these moieties resulted in the polymeric semiconductor composite film with smoother morphology and enhanced hole mobility. By employing this polymer with a distinct distribution of substituents and an innovative main chain structure as a hole transport material, we fabricated perovskite solar cells achieving an average efficiency of 25.1%. These cells also exhibited excellent stabilities under conditions of 85 °C thermal storage and 45 °C operation.

Acclimation temperature influences the thermal sensitivity of injury accumulation in Folsomia candida at extreme low and high temperatures

The importance of thermal acclimation for the Thermal Death Time (TDT) landscape of the common soil living springtail, Folsomia candida (Collembola, Isotomidae), was investigated. To this aim, we acclimated adult springtails at 10 °C (cold-acclimation) and 20 °C (warm-acclimation), respectively. In static thermal tolerance assays, we found the relationship between survival and exposure time at a number of stressful high and low temperatures. Using logistic modelling, we found, at each exposure temperature, the time until 50% mortality had been reached (Lt50). The exponential functions of TDT curves were found by linear regression of log10 Lt50 values against exposure temperature. Results showed that cold acclimation significantly increased cold tolerance and increased the temperature dependence of cold injury accumulation rate (increased the slope by 4 orders of magnitude) in F. candida. Hence, cold acclimation changed the status of this species from chill-susceptible to moderately chill-tolerant. The cellular injury accumulation at sub-zero temperatures was not related to freezing of body water in this study. Congruently, we found a significant negative effect of cold acclimation on heat tolerance and that cold acclimation decreased the thermal sensitivity of the heat injury accumulation rate. Different slopes of the TDT curves between acclimation groups indicated that acclimation shifted the proportional importance of cellular injury mechanisms or the nature of injury mechanisms. Finally, we compare and combine the TDT curves at extreme high and low temperatures with previously published results on longevity at benign temperatures (from 0 to 30 °C) and describe the full thermal niche of F. candida.

Heat Stress in Canola: Paving a Path Forward for Varieties With Improved Tolerance

AbstractCanola grown in years or locations with increased temperatures shows a significant decline in seed yield. Research has shown a ∼7 bu/ac yield loss with a 5.4°F increase in growing season temperatures. Given the importance of canola in western Canada and the fact that canola is a cool‐season crop, continued applied and basic research into heat tolerance is of critical importance. Earn 0.5 CEUs in Crop Management by reading this article and taking the quiz at https://web.sciencesocieties.org/Learning‐Center/Courses.

Quantitative trait locus (QTL) mapping and transcriptome profiling identify QTLs and candidate genes associated with heat stress response during reproductive development in Camelina sativa

AbstractCamelina sativa (L.) Crantz is a low‐input oilseed crop that has great potential in providing sustainable feedstock for biofuels and bioproducts. Climate change is threatening production of camelina with rising global temperatures. Elucidating the genetic response to high temperatures is essential for successful breeding of heat‐tolerant camelina varieties. Here, we report a combinatorial approach to identifying candidate genes associated with heat stress by quantitative trait locus (QTL) mapping and comparative transcriptome profiling. A population of recombinant inbred lines (RILs) was grown in a controlled growth chamber under the high‐temperature regimes for 14 days beginning at the onset of the reproductive stage. Several traits related to seed production were evaluated at maturity. The QTL analysis identified several regions with co‐located traits on chromosomes 8, 10, and 12. Two RILs with contrasting phenotypic responses to heat stress were chosen for gene expression profiling via RNA sequencing. Multiple pathways and genes were found to be strongly affected by heat stress, and many genes expressed differently between the two RILs. Several genes identified within the QTL regions were considered strong candidates that may control heat tolerance during reproduction in camelina. These studies provide resources for future studies that may assist in improving the heat tolerance of camelina.

Cross-species gut microbiota transplantation predictably affects host heat tolerance.

The gut microbiome is known to influence and have regulatory effects in diverse physiological functions of host animals, but only recently has the relationship between host thermal biology and gut microbiota been explored. Here, we examined how early-life manipulations of the gut microbiota in larval amphibians influenced their critical thermal maximum (CTmax) at different acclimation temperatures. We stripped the resident microbiome from egg masses of wild-caught wood frogs (Lithobates sylvaticus) via an antibiotic wash, and then inoculated the eggs with pond water (control), no inoculation, or the intestinal microbiota of another species that has a wider thermal tolerance - green frogs (Lithobates clamitans). We predicted that this cross-species transplant would increase the CTmax of the recipient wood frog larvae relative to the other treatments. In line with this prediction, green frog microbiome-recipient larvae had the highest CTmax while those with no inoculum had the lowest CTmax. Both the microbiome treatment and acclimation temperature significantly influenced the larval gut microbiota communities and α-diversity indices. Green frog microbiome-inoculated larvae were enriched in Rikenellaceae relative to the other treatments, which produce short-chain fatty acids and could contribute to greater energy availability and enhanced heat tolerance. Larvae that received no inoculation had a higher relative abundance of potentially pathogenic Aeromonas spp., which negatively affects host health and performance. Our results are the first to show that cross-species gut microbiota transplants alter heat tolerance in a predictable manner. This finding has repercussions for the conservation of species that are threatened by climate change and demonstrates a need to further explore the mechanisms by which the gut microbiota modulate host thermal tolerance.

Overexpression of the alfalfa (Medicago sativa) gene, MsKMS1, negatively regulates seed germination in transgenic tobacco (Nicotiana tabacum).

Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-associated proteins are a class of transmembrane proteins involved in intracellular trafficking pathways. However, the functions of many SNARE domain-containing proteins remain unclear. We have previously identified a SNARE-associated gene in alfalfa (Medicago sativa ) KILLING ME SLOWLY1 (MsKMS1 ), which is involved in various abiotic stresses. In this study, we investigated the function of MsKMS1 in the seed germination of transgenic tobacco (Nicotiana tabacum ). Phylogenetic analysis showed that MsKMS1 was homologous to the SNARE-associated or MAPR component-related proteins of other plants. Germination assays revealed that MsKMS1 negatively regulated seed germination under normal, D-mannitol and abscisic acid-induced stress conditions, yet MsKMS1 -overexpression could confer enhanced heat tolerance in transgenic tobacco. The suppressive effect on germination in MsKMS1 -overexpression lines was associated with higher abscisic acid and salicylic acid contents in seeds. This was accompanied by the upregulation of abscisic acid biosynthetic genes (ZEP and NCED ) and the downregulation of gibberellin biosynthetic genes (GA20ox2 and GA20ox3 ). Taken together, these results suggested that MsKMS1 negatively regulated seed germination by increasing abscisic acid and salicylic acid contents through the expression of genes related to abscisic acid and gibberellin biosynthesis. In addition, MsKMS1 could improve heat tolerance during the germination of transgenic tobacco seeds.

Two lncRNAs of Chinese cabbage confer Arabidopsis with heat and drought tolerance

Two lncRNAs of Chinese cabbage confer Arabidopsis with heat and drought tolerance

Resistance of Kalmyk cattle breed to high ambient temperatures of the highlands of the North Caucasus

The purpose of the research is to establish indicators of heat resistance and study the growth of Kalmyk cattle youth in different natural, climatic, organizational and technological conditions in the highlands of the Kabardino-Balkarian Republic. The investigations were carried out in LLC «Dargan» (Chereksky district, in village Gerpegezh) and LLC «Malka» (Zolsky district, in village Malka) of the Kabardino-Balkarian Republic of the Kalmyk breed bulls during the period of grazing (from 7 to 12 months). The highest values of the heat resistance index and tolerance coefficient were recorded at the beginning of the grazing period in species of both farms, when the ambient temperature during the day was within comfortable limits for the species as a whole. Subsequently, the heat resistance indicators were decreased by the middle of the analyzed period of detention, which is explained by the temperature stress for the body of the experimental animals. However, temperature conditions and resistance were restored to their original values for them by the end of the experiment. Inter-farm divergences in growth intensity in age period of 7-9 months were 31 g (P<0.95), 9-12 months - 65 g (P<0.999) and for the entire period - 52 g (P<0.99). The largest absolute increase in live weight over the analyzed period was distinguished by bulls from LLC «Malka», which were under other conditions, recorded the lowest feed costs per 1 kg of live weight gain. Thus, the differences in the cost of energy feed units in comparison with individuals from «Dargan» LLC were 0.18, digestible protein was 11 g.

Basic evaluation of the CRISPR/Cas system stability for application to paper-based analytical devices.

Despite the promising features of the CRISPR/Cas system for application to point-of-care nucleic acid tests, there are only a few reports on its integration into paper-based analytical devices (PADs) for the purpose of assay simplification. In most cases, paper platforms have only been used for the final signal readout in an assay otherwise performed in a test tube. Therefore, there is very limited information on the suitability of the CRISPR/Cas system for on-device reagent storage. To fill this gap, the current work primarily investigated the influence of various factors, including the type of paper, reagent drying method, effect of stabilizers, and storage condition on the storage stability of reagents necessary for CRISPR-based assays on paper substrates, by comparing the fluorescence signal emitted by the trans-cleavage of the dsDNA-activated Cas12a complex. The results obtained in the form of fluorescence signals emitted after trans-cleavage of a ssDNA probe through a dsDNA-activated Cas12a complex on paper substrates showed that CRISPR-related reagents spontaneously dried at room temperature on BSA blocked paper retained over 70% of their initial activity when stored at -20 °C for 28 days, independent of the type of paper substrates, which was improved by the addition of sucrose as a stabilizer. In addition, reagents dried on paper substrates under the optimized conditions exhibited stronger heat tolerance at temperatures above 65 °C compared to their corresponding solutions. This work is expected to contribute to the future development of fully integrated PADs relying on CRISPR/Cas systems for point-of-care applications requiring no additional reagent handling.

Nanoliter-Scale Sample Preparation for Single-Cell Proteomic Analysis Using Glass-Oil-Air-Droplet Chip.

Single-cell proteomic analyses are of fundamental importance in order to capture biological heterogeneity within complex cell systems' heterogeneous populations. Mass spectrometry (MS)-based proteomics is a promising alternative for quantitative single-cell proteomics. Various techniques are continually evolving to address the challenges of limited sample material, detection sensitivity, and throughput constraints. In this chapter, we describe a nanoliter-scale glass-oil-air-droplet (gOAD) chip engineered for heat tolerance, which combines droplet-based microfluidics and shotgun proteomic analysis techniques to enable multistep sample pretreatment.

Chromosome-scale assembly and gene editing of Solanum americanum genome reveals the basis for thermotolerance and fruit anthocyanin composition.

Solanum americanum serves as a promising source of resistance genes against potato late blight and is considered as a leafy vegetable for complementary food and nutrition. The limited availability of high-quality genome assemblies and gene annotations has hindered the exploration and exploitation of stress-resistance genes in S. americanum. Here, we present a chromosome-level genome assembly of a thermotolerant S. americanum ecotype and identify a crucial heat-inducible transcription factor gene, SaHSF17, essential for heat tolerance. The CRISPR/Cas9 system-mediated knockout of SaHSF17 results in remarkably reduced thermotolerance in S. americanum, exhibiting a significant suppression of multiple HSP gene expressions under heat treatment. Furthermore, our transcriptome analysis and anthocyanin component investigation of fruits indicated that delphinidins are the major anthocyanins accumulated in the mature dark-purple fruits. The accumulation of delphinidins and other pigment components during fruit ripening in S. americanum coincides with the transcriptional regulation of key genes, particularly the F3'5'H and F3'H genes, in the anthocyanin biosynthesis pathway. By integrating existing knowledge, the development of this high-quality reference genome for S. americanum will facilitate the identification and utilization of novel abiotic and biotic stress-resistance genes for improvement of Solanaceae and other crops.

Dissecting the effect of heat stress on durum wheat under field conditions.

Heat stress negatively affects wheat production in several ways, mainly by reducing growth rate, photosynthetic capacity and reducing spike fertility. Modeling stress response means analyzing simultaneous relationships among traits affecting the whole plant response and determinants of grain yield. The aim of this study was to dissect the diverse impacts of heat stress on key yield traits and to identify the most promising sources of alleles for heat tolerance. We evaluated a diverse durum wheat panel of 183 cultivars and breeding lines from worldwide, for their response to long-term heat stress under field conditions (HS) with respect to non stress conditions (NS), considering phenological traits, grain yield (GY) and its components as a function of the timing of heat stress and climatic covariates. We investigated the relationships among plant and environmental variables by means of a structural equation model (SEM) and Genetic SEM (GSEM). Over two years of experiments at CENEB, CIMMYT, the effects of HS were particularly pronounced for the normalized difference vegetation index, NDVI (-51.3%), kernel weight per spike, KWS (-40.5%), grain filling period, GFP (-38.7%), and GY (-56.6%). Average temperatures around anthesis were negatively correlated with GY, thousand kernel weight TKW and test weight TWT, but also with spike density, a trait determined before heading/anthesis. Under HS, the correlation between the three major determinants of GY, i.e., fertile spike density, spike fertility and kernel size, were of noticeable magnitude. NDVI measured at medium milk-soft dough stage under HS was correlated with both spike fertility and grain weight while under NS it was less predictive of grain weight but still highly correlated with spike fertility. GSEM modeling suggested that the causal model of performance under HS directly involves genetic effects on GY, NDVI, KWS and HD. We identified consistently suitable sources of genetic resistance to heat stress to be used in different durum wheat pre-breeding programs. Among those, Desert Durums and CIMMYT'80 germplasm showed the highest degree of adaptation and capacity to yield under high temperatures and can be considered as a valuable source of alleles for adaptation to breed new HS resilient cultivars.

Screening and identification of heat tolerance in Indian wheat genotypes using generalized regression neural network (GRNN) model

The present study using a generalized regression neural network (GRNN) model was carried out to check the effect of high temperature on five Indian bread wheat genotypes, namely, C306, K7903, CBW12, HD2329, and HD2428, and to develop an algorithm for the screening and identification of heat tolerance in wheat. A highly significant differential survivability in response to the temperature induction response technique with germinating seeds was observed for the five wheat genotypes. Maximum survivability was observed for C306 and K7903, whereas HD2329 and HD2428 showed minimum survival in response to lethal temperature stress. Similarly, at the mature plant stage, in response to heat treatment of 34°C/26°C (day/night), all five wheat genotypes showed a significant difference in chlorophyll a fluorescence, total chlorophyll content, and the reduction of 1,1- diphenyl-2-picryl-hydrazyl (DPPH) in response to heat treatment. The genotypes, C306, K7903, and CBW12 showed better performance for all the chlorophyll a fluorescence parameters under study including Fo, Fv/Fm, qL, qP, NPQ, θPSII, ETR, along with the total chlorophyll content and DPPH reduction, in contrast, the genotypes, HD2329 and HD2428 performed poorly for all parameters including chlorophyll a fluorescence parameters, total chlorophyll, and DPPH reduction. Higher inflection temperature and peak temperature were observed in C306 and K7903, in contrast, HD2329 and HD2428 showed significantly lower inflection temperature and peak temperature. Higher expression of the selected genes involved in photosynthesis and ROS scavenging was observed in C306 and K7903 relative to HD2329 and HD2428. On the basis of the different chlorophyll a fluorescence parameters, the algorithm was developed for the calculation of the heat susceptibility index. The algorithm was independently checked for the identification and segregation of all the five wheat genotypes taken in this study as tolerant, moderate, and susceptible. For all the genotypes, the algorithm was able to predict the heat susceptibility of the genotypes with high accuracy. Hence, the algorithm in combination with chlorophyll a fluorescence can be used for the screening of wheat and other plant species in response to abiotic stress, especially heat stress.

Understanding Heat‐Associated Adult Platichthys stellatus Mortality: Differential Transcriptome Analysis of Juvenile and Adult Starry Flounder Liver under Heat Stress

The starry flounder Platichthys stellatus, an economically important benthic fish species widely distributed throughout the North Pacific Ocean, exhibits poor heat tolerance, resulting in frequent adult mass mortality in aquaculture settings. Heat stress disrupts the energy metabolism of P. stellatus, elevating blood glucose and implying its sensitivity to rising water temperatures. In particular, the survival of adult fish in aquaculture settings during the summer season is less than that of larvae or juveniles. This study aimed to understand the heat stress‐associated survival of adults by focusing on the molecular pathways of glycolysis/gluconeogenesis using comparative transcriptome analysis. Transcriptomes were obtained by RNA sequencing of P. stellatus livers of adults exposed to 16 and 28°C, together with juveniles at the same conditions. A total of 16,121,503–18,774,222 raw paired‐end reads were obtained after trimming. The assembled unigenes (39,489 out of 127,460) were annotated in the nr, Clusters of Orthologous Groups (COG), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Swiss‐Prot databases. A total of 6,858 differentially expressed genes were found in juveniles and adults at control (16°C) and high (28°C) water temperatures. Juveniles and adults had 1,856 genes downregulated and 1,548 genes upregulated at the 16°C control water temperature and 1,055 genes downregulated and 1,231 genes upregulated at 28°C, overall involving at least 47 KEGG pathways. When raising the water temperature and comparing the DEGs of juveniles and adults, respectively, we found that both groups showed similar upregulation patterns for the major heat shock protein (HSP) genes under temperature‐increasing conditions, indicating a conserved response mechanism. Additionally, both juvenile and adult fish showed similar upregulation of ER stress‐related genes, including endoplasmic reticulum chaperone BiP (BiP) and homocysteine‐responsive endoplasmic reticulum‐resident ubiquitin‐like domain member 1 (HERP), suggesting consistent transcriptional changes associated with ER stress under heat stress conditions. However, notable differences were observed in the expression of inflammation and immune response‐related genes, and juvenile P. stellatus showed upregulation of immune costimulatory protein B7‐H3 (B7H3) and immunoglobulin superfamily member 9 (IGSF9), while adults showed upregulation of high‐affinity immunoglobulin epsilon receptor subunit gamma (FCER1G), V‐type immunoglobulin domain‐containing suppressor of T‐cell activation (VSIR), and immunoglobulin superfamily DCC subclass member 3 (IGDCC3). Especially, phosphoglucomutase (PGM), glucose‐6‐phosphatase catalytic subunit (G6PC), phosphofructokinase (PFK), and bisphosphoglycerate mutase (BPGM), the enzymes involved in the glycolysis/gluconeogenesis pathway, showed significantly higher FPKM in adult P. stellatus than in juveniles. Overall, this study provides valuable insights into the transcriptional responses of P. stellatus to heat stress, which differ with age and may inform the development of strategies to improve the survival and productivity of this economically important fish species in aquaculture.

Reaction-norm animal model analysis of average daily gain heat tolerance in purebred Duroc pigs.

The present study aimed to genetically improve growth performance under high-heat environments by specifically designing a reaction-norm animal model (RNAM) for purebred Duroc pigs in Japan. A total of 54,750 records of average daily gain (ADG) measured for pigs reared at four farms in different prefectures were analyzed. Estimated maximum daily temperatures at the respective farm locations were used to calculate the average cumulative thermal load (TL). The TL values served as an indicator of high-heat environments for pigs. The plausible cumulative period length and threshold temperature for calculating TL were determined to be 8 weeks until just before shipping and 25°C, respectively. Variance components were estimated via RNAM analysis using TL as a linear covariate. The estimated additive genetic variances under both responsive and non-responsive to TL were found to be significant. Moreover, the estimated heritability of ADG ranged from 0.38 to 0.73 for TL values of 0-8. These results suggest that the RNAM developed holds the potential for improving the genetic ability of growth under high-heat environments in pigs.

Precise phenotyping approach or characterization of terminal heat tolerance in bread wheat (Triticum aestivum L.)

Precise phenotyping approach or characterization of terminal heat tolerance in bread wheat (Triticum aestivum L.)

Advancing Heat Tolerance in Cotton through Integration of Multiple Stress Tolerance Indices and Multivariate Analyses

Advancing Heat Tolerance in Cotton through Integration of Multiple Stress Tolerance Indices and Multivariate Analyses

ECR Spotlight – Jason Dallas

ECR Spotlight is a series of interviews with early-career authors from a selection of papers published in Journal of Experimental Biology and aims to promote not only the diversity of early-career researchers (ECRs) working in experimental biology but also the huge variety of animals and physiological systems that are essential for the ‘comparative’ approach. Jason Dallas is an author on ‘ Cross-species gut microbiota transplantation predictably affects host heat tolerance’, published in JEB. Jason conducted the research described in this article while a PhD student in Dr Robin Warne's lab at Southern Illinois University, USA. He is now a postdoctoral research assistant in the lab of Dr Donald Walker at Middle Tennessee State University, USA, investigating herpetofauna ecophysiology including thermal biology, host microbiome and responses to human activity.

Development and validation of markers to improve heat tolerance in flowering stage of Laos elite rice cultivar

Development and validation of markers to improve heat tolerance in flowering stage of Laos elite rice cultivar

Performance, Physiological Status, and Heat Tolerance of Holstein Friesian Dairy Cows at Different Lactation Phases

Performance, Physiological Status, and Heat Tolerance of Holstein Friesian Dairy Cows at Different Lactation Phases