High Temperature Tolerance Research Articles

Differences between the wild-type and cultivated Gracilariopsis lemaneiformis revealed by quantitative proteome and gene expression profiling analysis

Abstract The seaweed Gracilariopsis lemaneiformis is widely cultivated in the southern and northern coasts of China, and is mainly used for agar extraction and abalone feed. The cultivated strain of G. lemaneiformis 981 has various advantages over the wild type such as growth rate and high-temperature tolerance. Therefore, it is necessary to investigate the differences between the wild-type and cultivated G. lemaneiformis. Here, 648 up-regulated and 837 down-regulated proteins were screened using the isobaric tags for relative and absolute quantitation (iTRAQ) technique, and these differentially expressed proteins (DEPs) were concentrated in the pathways including “Ribosome”, “Photosynthesis-antenna proteins”, “alpha-Linolenic acid metabolism”, and “Phenylpropanoid biosynthesis”. The most prominent pathway was “Ribosome”, namely, 116 out of 119 ribosome-associated proteins were up-regulated in G. lemaneiformis 981 compared to the wild type. Subsequently, multiple reaction monitoring (MRM) validated the credibility of the iTRAQ results. Finally, “Phenylpropanoid biosynthesis” and “Photosynthesis-antenna proteins” pathways were also found to be significantly changed in G. lemaneiformis 981 validated by gene expression profiling analysis. Altogether, these results, in combination with chlorophyll fluorescence parameters, unveiled the possible mechanism of differences in growth and anti-abiotic stresses between the wild-type and cultivated G. lemaneiformis, which would provide a reference for breeding of excellent seaweeds.

Dynamic Physiological Responses of Cinnamomum camphora with Monoterpene Protection under High Temperature Shock

Monoterpenes can protect plants against high temperature, but the early events of protection are still unknown. In this study, the dynamic variations in reactive oxygen species metabolism, photosynthetic capacity, and related gene expression in linalool, eucalyptol, and camphor chemotypes of Cinnamomum camphora with and without monoterpene emission under 6 h high-temperature stress were investigated. With respect to the control (28 °C), 40 °C and Fos + 40 °C (fosmidomycin inhibited monoterpene biosynthesis under 40 °C) treatments increased H2O2 and thiobarbituric acid reactive substance levels in the three chemotypes, but without significant differences between the two treatments after 2 h. Compared with the 40 °C treatment, the Fos + 40 °C treatment further aggravated the increase after 4 h, with increases of 13.8%, 12.3%, and 12.3% in H2O2 levels as well as 16.5%, 17.4%, and 9.1% in thiobarbituric acid reactive substance levels, respectively, in linalool, eucalyptol, and camphor chemotypes. When the three chemotypes were treated with 40 °C and Fos + 40 °C, the ascorbic acid content was gradually decreased during the 2 h treatment. After 4 h, the Fos + 40 °C treatment further aggravated the decrease in ascorbic acid content, with decreases of 10.6%, 9.8%, and 20.1%, respectively, in the eucalyptol, linalool, and camphor chemotypes. This could be caused by the further down-regulation of the key gene GGP in antioxidant biosynthesis. Meanwhile, two genes (VTE3 and 4CL) in other non-enzymatic antioxidant formation were also further down-regulated in Fos + 40 °C treatment for 4 h. These might lead to the further increase in reactive oxygen species levels in Fos + 40 °C treatment lacking non-enzymatic antioxidants. The photosynthetic electron yield and transfer (φPo, Ψo and φEo) in the three chemotypes were significantly (p < 0.05) decreased under the 40 °C and Fos + 40 °C treatments for 0.5 h, and the photosynthetic rate was significantly (p < 0.05) decreased in the two treatments for 1 h. After 4 h, the Fos + 40 °C treatment aggravated the decrease, as the genes encoding the components of photosystem II (psbP and psbW) and ribulose-1,5-bisphosphate carboxylase/oxygenase (rbcS and rbcL) were further down-regulated. These dynamic variations in the early events suggested that monoterpenes should act as signaling molecules to improve plant thermotolerance, as blocking monoterpene biosynthesis did not cause immediate effects on the physiological responses in contrast to the monoterpene-emitting plants during the 2 h high temperature stress, but resulted in serious damages after 4 h for suppressing related gene expression. This not only provides new proof for the isoprenoid thermotolerance mechanism by serving a signaling function, but also promotes the utilization of monoterpenes as anti-high-temperature agents, and the cultivation of high-temperature tolerance varieties with abundant monoterpene emission.

Determination of the tolerance of physiological, morphological, and yield parameters of landrace durum wheat (Triticum durum Desf.) to high-temperature stress

In the South-eastern Anatolia Region, where the climate is favorable to cultivation for durum wheat, there have been notable reductions in both yield and quality due to biotic and abiotic stress factors in the region. Primary one of these stresses is high-temperature stress. High-temperature stress, specifically during the late flowering stage and early grain filling stage, results in substantial reductions in both crop yield and quality. In this study, several practical, easily and rapidly quantifiable physiological, morphological, and yield-related parameters that may be used in durum wheat improvement programs in the region for high-temperature stress tolerance were investigated. Ninety landrace durum genotypes and 4 standard cultivars were used. The study was carried out at GAP (South-eastern Anatolia Project) International Agricultural Research and Training Centre in an air conditioning room according to an augmented design under optimum conditions and stressful conditions where high-temperature stress was created. Compared to optimum conditions, there were reductions in flag leaf greening time by 20%, days to maturity by 7%, spike length by 10%, peduncle length by 18%, grain filling time by 23%, number of spikelets on the spike by 12%, number of grains on the spike by 39%, and thousand-kernel weight by 33%, while grain filling rate increased under high-temperature stress conditions. The genotypes 82, 83, 87, 88, 99, and 103 and the standard varieties Artuklu and Sümerli prevailed in both optimum and stress conditions. The fact that leaf erectness, flag leaf greening time, grain filling time, and leaf chlorophyll content among morphological and physiological characteristics had a significant correlation with yield components under both conditions indicates that these characteristics can be used as selection criteria for tolerance to stressful conditions in the region.

The Jinggangmycin-induced Mthl2 gene regulates the development and stress resistance in Nilaparvata lugens Stål (Hemiptera: Delphacidae)

Methuselah (Mth) belongs to the GPCR family B, which regulates various biological processes and stress responses. The previous transcriptome data showed jinggangmycin (JGM)-induced Mthl2 expression. However, its detailed functional role remained unclear in brown planthopper, Nilaparvata lugens Stål. In adult N. lugens, the Mthl2 gene showed dominant expressions, notably in ovaries and fat body tissues. The 3rd instar nymphs treated with JGM increased starvation, oxidative stress, and high temperature (34 °C) tolerance of the adults. On the contrary, under dsMthl2 treatment, completely opposite phenotypes were observed. The lipid synthesis genes (DGAT1and PNPLA3) of both females and males treated with JGM in the nymphal stage were observed with high expressions, while the lipolysis of the Lipase 3 gene was observed with low expressions. The JGM increased triglyceride (TG) content, fat body droplet size, and the number of fat body droplets. The same treatment also increased the Glutathione S-transferase (GST), catalase (CAT), and superoxide dismutase (SOD) activities. An increase in the heat shock protein (HSP70 and HSP90) expression levels was also observed under JGM treatment but not dsMthl2. The current study demonstrated the influential role of the Mthl genes, particularly the Mthl2 gene, in modulating the growth and development and stress-responsiveness in N. lugens. Thus, providing a platform for future applied research programs controlling N. lugens population in rice fields.

The role of cytochrome P450 3A2 and 4V2 in response to high-temperature stress in Tetranychus truncatus (Acari: Tetranychidae).

Temperature is an important factor influencing the physiological activities of agricultural pests. Therefore, understanding pest physiological activities and the molecular response to high-temperature stress is of paramount importance for pest management. Tetranychus truncatus Ehara (Acari: Tetranychidae) is a harmful organism, that may cause serious harm to crops such as corn and cotton in high-temperature environments. Cytochrome P450 (CYP450) is induced by high-temperature stress, and it plays an important role in the resistance of spider mites to high temperatures. Because of their role in high-temperature tolerance, the cytochrome P450 genes of thespider mite are attracting more and more attention. In this study, we identified and analyzed CYP450 genes in T. truncatus to investigate their potential roles in growth and development and the resistance to high-temperature stress. Based on phylogenetic and structural analyses, we identified 17 CYP450 genes in T. truncatus. RNA-seq and real-time quantitative PCR (RT-qPCR) revealed differential expression patterns of these genes at different developmental stages and levels of high-temperature stress resistance. The RNA interference results of selected CYP450 showed that when TtCYP3A2 and TtCYP4V2 were silenced by feeding on dsRNA, respectively, the high-temperature resistance of T. truncatus was decreased, which indicated that the expression of these two CYP450 genes in this species may be related to high-temperature tolerance. Our results provide potential evidence for the response of spider mites to high-temperature stress and help to improve the understanding of T. truncatus's ability to resist high-temperature stress.

Synthesis of novel modified acrylamide copolymers for montmorillonite flocculants in water-based drilling fluid

A study was conducted to treat the water-based drilling fluid through coagulation-flocculation. Innovative modified acrylamide copolymers were utilized as montmorillonite flocculants to improve drilling performance and reduce environmental contamination. A series of acrylamide copolymers was prepared by in situ free radical polymerization in aqueous medium using ammonium persulfate as a radical initiator. The chemical structure of the prepared copolymers was confirmed by FT-IR (Fourier-Transform Infrared Spectroscopy) and the polydispersity indices of the copolymers determined using gel permeation chromatography. Thermal gravimetric analysis showed that the copolymers have a very high temperature tolerance, i.e. they are stable up to 390 °C. In this paper, acrylamide copolymers were used as coagulant with cationic, anionic groups or both of them simultaneously. Consequently, in order to clarify the relationship between inhibitive properties, sedimentation volume measurement, SEM (scanning electron microscope), XRD (X-ray diffraction) and contact angle were adopted. Some factors including molecular weight and molecular chain affecting the interaction between copolymers and clay particles were analyzed. Anionic sample with the highest molecular weight can reduce the interlayer spacing of the hydrated clay to the minimum. Amphoteric sample exhibits the best performance as a coagulant in comparison with other copolymers.

Development of Short Duration, Tolerance to High Temperature and Bipolaris Leaf Blight, and Moderately Susceptible to Blast Disease of Wheat Genotype with Trials in Various Agroecological Zones in Bangladesh

Wheat production in Bangladesh faces to the detrimental effects of biotic and abiotic stresses that have been exacerbated by climate change. The development of short duration, high temperature and disease tolerant wheat variety is the most importance to produce higher yield combating the deleterious effects of the stresses. Some wheat lines (line was expressed by E) were evaluated at the different research stations of Bangladesh Wheat and Maize Research Institute (BWMRI) and farmers’ fields in consecutively three years under irrigated timely sowing (ITS) and irrigated late sowing (ILS) conditions. The days to heading (DH), days to maturity (DM), plant height (PH), spikelet spike-1 (SPS), grain spike-1 (GPS), thousand grain weight (TGW), and grain yield were depicted comparatively higher in ITS and ILS than ITS, but the severity of Bipolaris leaf blight (BpLB) and blast diseases were exhibited lower in BAW 1194 (E9) line than check varieties and other lines same conditions (BAW = Bangladesh Advanced Wheat). Those phenotypic and yield contributing characters, and BpLB and blast diseases were also observed lower in ILS than other genotypes. Further, E9 exhibited the lower percentage of yield loss in the ILS compared to ITS than check and other genotypes indicated its high temperature tolerance. In addition, E9 exhibited relatively higher grain yield than other genotypes in the candidate variety demonstration and multiplication yield trials. Therefore, BAW 1194 line may be released as a short duration, tolerance to high temperature and BpLB, and moderately tolerance to blast disease wheat variety to accelerate wheat production.

Genome-wide identification of the heat shock transcription factor gene family in two kiwifruit species.

High temperatures have a significant impact on plant growth and metabolism. In recent years, the fruit industry has faced a serious threat due to high-temperature stress on fruit plants caused by global warming. In the present study, we explored the molecular regulatory mechanisms that contribute to high-temperature tolerance in kiwifruit. A total of 36 Hsf genes were identified in the A. chinensis (Ac) genome, while 41 Hsf genes were found in the A. eriantha (Ae) genome. Phylogenetic analysis revealed the clustering of kiwifruit Hsfs into three distinct groups (groups A, B, and C). Synteny analysis indicated that the expansion of the Hsf gene family in the Ac and Ae genomes was primarily driven by whole genome duplication (WGD). Analysis of the gene expression profiles revealed a close relationship between the expression levels of Hsf genes and various plant tissues and stress treatments throughout fruit ripening. Subcellular localization analysis demonstrated that GFP-AcHsfA2a/AcHsfA7b and AcHsfA2a/AcHsfA7b -GFP were localized in the nucleus, while GFP-AcHsfA2a was also observed in the cytoplasm of Arabidopsis protoplasts. The results of real-time quantitative polymerase chain reaction (RT-qPCR) and dual-luciferase reporter assay revealed that the majority of Hsf genes, especially AcHsfA2a, were expressed under high-temperature conditions. In conclusion, our findings establish a theoretical foundation for analyzing the potential role of Hsfs in high-temperature stress tolerance in kiwifruit. This study also offers valuable information to aid plant breeders in the development of heat-stress-resistant plant materials.

Integrative analysis of genome and transcriptome reveal the genetic basis of high temperature tolerance in pleurotus giganteus (Berk. Karun & Hyde)

BackgroundPleurotus giganteus is a commonly cultivated mushroom with notable high temperature resistance, making it significant for the growth of the edible fungi industry in the tropics. Despite its practical importance,, the genetic mechanisms underlying its ability to withstand high temperature tolerance remain elusive.ResultsIn this study, we performed high-quality genome sequencing of a monokaryon isolated from a thermotolerant strain of P. giganteus. The genome size was found to be 40.11 Mb, comprising 17 contigs and 13,054 protein-coding genes. Notably, some genes related to abiotic stress were identified in genome, such as genes regulating heat shock protein, protein kinase activity and signal transduction. These findings provide valuable insights into the genetic basis of P. giganteus’ high temperature resistance. Furthermore, the phylogenetic tree showed that P. giganteus was more closely related to P. citrinopileatus than other Pleurotus species. The divergence time between Pleurotus and Lentinus was estimated as 153.9 Mya, and they have a divergence time with Panus at 168.3 Mya, which proved the taxonomic status of P. giganteus at the genome level. Additionally, a comparative transcriptome analysis was conducted between mycelia treated with 40 °C heat shock for 18 h (HS) and an untreated control group (CK). Among the 2,614 differentially expressed genes (DEGs), 1,303 genes were up-regulated and 1,311 were down-regulated in the HS group. The enrichment analysis showed that several genes related to abiotic stress, including heat shock protein, DnaJ protein homologue, ubiquitin protease, transcription factors, DNA mismatch repair proteins, and zinc finger proteins, were significantly up-regulated in the HS group. These genes may play important roles in the high temperature adaptation of P. giganteus. Six DEGs were selected according to fourfold expression changes and were validated by qRT-PCR, laying a good foundation for further gene function analysis.ConclusionOur study successfully reported a high-quality genome of P. giganteus and identified genes associated with high-temperature tolerance through an integrative analysis of the genome and transcriptome. This study lays a crucial foundation for understanding the high-temperature tolerance mechanism of P. giganteus, providing valuable insights for genetic modification of P. giganteus strains and the development of high-temperature strains for the edible fungus industry, particularly in tropical regions.

Transcriptome analysis reveals the molecular mechanisms of heterosis on thermal resistance in hybrid tilapia (Oreochromi niloticus ♀×Oreochromi aureus ♂)

Heterosis is a widely observed biological phenomenon in fishes, in which hybrids exhibit superior traits to their parents. However, the underlying molecular mechanisms for heterosis are not well understood. Tilapia is an economically important aquaculture resource with high commercial value, and the phenomenon of high temperature tolerance in hybrid tilapia (Oreochromis niloticus ♀ × Oreochromis aureus ♂, AN) has been observed in recent studies. Uncovering the molecular mechanisms underlying this phenomenon could provide theoretical support for heterosis in thermal tolerance. To investigate the gene expression patterns and alternative splicing events associated with heat stress in tilapia, RNA Sequencing was conducted at control temperature (28 °C) and heat stress temperatures (36 °C and 39 °C). A total of 280, 260, and 261 genes with significantly divergent alternative splicing events were identified in O.niloticus (NL), O.aureus (AR), and O. niloticus ♀ × O.aureus ♂ (AN), respectively. In the heat stress groups (39 °C groups), 83.59% (23779 out of 28446) of the expressed genes showed non-additive expression patterns, and the highest proportion (35.14%) of these genes exhibited over-dominance expression patterns. KEGG pathway enrichment analysis showed that the overlapping genes among common differentially expressed genes (DEGs) and non-additively expressed genes (NAGs) were significantly enriched in apoptosis, adipocytokine signaling, and insulin signaling pathways. Furthermore, among these overlapping genes, 32 genes had undergone alternative splicing events in AN, which may play an important role in the thermal resistance of hybrid tilapia. These findings shed light on the physiological regulation mechanisms that allow hybrid tilapia to exhibit better thermal resistance than their parents. They provide important insights into the molecular basis of heterosis in tilapia and have potential implications for improving aquaculture practices.

The gene AccCyclin H mitigates oxidative stress by influencing trehalose metabolism in Apis cerana cerana.

Environmental stress can induce oxidative stress in Apis cerana cerana, leading to cellular oxidative damage, reduced vitality, and even death. Currently, owing to an incomplete understanding of the molecular mechanisms by which A. cerana cerana resists oxidative damage, there is no available method to mitigate the risk of this type of damage. Cyclin plays an important role in cell stress resistance. The aim of this study was to explore the in vivo protection of cyclin H against oxidative damage induced by abiotic stress in A. cerana cerana and clarify the mechanism of action. We isolated and identified the AccCyclin H gene in A. cerana cerana and analysed its responses to different exogenous stresses. The results showed that different oxidative stressors can induce or inhibit the expression of AccCyclin H. After RNA-interference-mediated AccCyclin H silencing, the activity of antioxidant-related genes and related enzymes was inhibited, and trehalose metabolism was reduced. AccCyclin H gene silencing reduced A. cerana cerana high-temperature tolerance. Exogenous trehalose supplementation enhanced the total antioxidant capacity of A. cerana cerana, reduced the accumulation of oxidants, and improved the viability of A. cerana cerana under high-temperature stress. Our findings suggest that trehalose can alleviate adverse stress and that AccCyclin H may participate in oxidative stress reactions by regulating trehalose metabolism. © 2023 Society of Chemical Industry.

Limits of thermal and hydrological tolerance in a foundation tree species (Populus fremontii) in the desert southwestern United States.

Populus fremontii is among the most dominant, and ecologically important riparian tree species in the western United States and can thrive in hyper-arid riparian corridors. Yet, P. fremontii forests have rapidly declined over the last decade, particularly in places where temperatures sometimes exceed 50°C. We evaluated high temperature tolerance of leaf metabolism, leaf thermoregulation, and leaf hydraulic function in eight P. fremontii populations spanning a 5.3°C mean annual temperature gradient in a well-watered common garden, and at source locations throughout the lower Colorado River Basin. Two major results emerged. First, despite having an exceptionally high Tcrit (the temperature at which Photosystem II is disrupted) relative to other tree taxa, recent heat waves exceeded Tcrit , requiring evaporative leaf cooling to maintain leaf-to-air thermal safety margins. Second, in midsummer, genotypes from the warmest locations maintained lower midday leaf temperatures, a higher midday stomatal conductance, and maintained turgor pressure at lower water potentials than genotypes from more temperate locations. Taken together, results suggest that under well-watered conditions, P. fremontii can regulate leaf temperature below Tcrit along the warm edge of its distribution. Nevertheless, reduced Colorado River flows threaten to lower water tables below levels needed for evaporative cooling during episodic heat waves.

Correlation between physiological and yield attributes in bread wheat genotypes for high temperature tolerance

Aim: The aim of the present study was to observe the role of heat stress in the correlation of physiological and yield attributes in bread wheat genotypes. Methodology: Seven wheat genotypes (PBW781, RWP-2018-30, PBW821, RWP-2018-31, WH1239, RWP-2018-26, and RWP-2018-32) along with three check varities namely DBW14, WH730, and RAJ3765 were grown under timely sown (TS) and late sown (LS) conditions in the field research area of Wheat Section, CCS HAU, Hisar (2018-19). For generating heat stress, delay in sowing (4 weeks) was done in late sown from timely sown. These wheat lines were assessed for several physiological and yield attributes under both conditions and one genotype was found to be heat-tolerant under late sown condition. Results: PBW821 was classified as thermo-tolerant due to maximum grain yield, higher normalized difference vegetation index, photosynthetic rate, chlorophyll content, and lower canopy temperature compared to other varieties under late sown conditions. Interpretation: Identification of a heat-resistant wheat genotype would be a valuable resource for developing high-yielding cultivars under high-temperature conditions, and these findings might also be used in breeding programs. Key words: Grain yield, Heat tolerance, Physiological traits, Triticum aestivum

Marker assisted backcross analysis for high temperature tolerance in rice

Marker assisted backcross analysis for high temperature tolerance in rice

Biochemical Basis of Abiotic Stress Tolerance in Native Isolates of <i>Beauveria bassiana</i> (Balsamo) Vuillemin from Kerala

A study on the screening of Beauveria bassiana (Balsamo) Vuillemin native isolates for abiotic stress tolerance was carried out at the Department of Agricultural Entomology, College of Agriculture, Vellanikkara, Thrissur, Kerala during 2019-2023. The growth and biochemical parameters of the three native isolates of B. bassiana (BTL1: OP271760, BTL2: OP290199 and PKDE: OP292066) were studied under different abiotic stress conditions viz., temperature, water stress, acidity and salinity. The results revealed that the highest temperature tolerance (40° C) was displayed by the B. bassiana isolate PKDE. It also survived at high water stress (45% polyethylene glycol), acidic (pH2) and saline (1.5 M) conditions. The analysis of biochemical parameters in stress tolerant isolate revealed that the greatest levels of trehalose (2.033± 0.025, 2.043± 0.006 mg/ min/ g of mycelia), catalase (0.0072± 0.007, 0.0032± 0.003 EU/ min/ mg protein) and peroxidase (0.0602± 0.005, 0.0175± 0.017 EU/ min/ mg tissue weight) were observed after exposure to high temperature and water stress, respectively. This shows that exposure to abioticstress and biochemical parameters are closely related and can be used as determinants for evaluating the potential of biocontrol agents.

Rice hull biochar improved the growth of tree peony (Paeonia suffruticosa Andr.) by altering plant physiology and rhizosphere microbial communities

High temperatures due to global warming threaten agricultural production. The application of biochar may enhance plant growth and soil fertility, but whether it exerts an influence on plants under high-temperature stress has not been confirmed. In this study, the effects of biochar on physiological and biochemical indices of high-temperature tolerance were evaluated in the tree peony. It was found that biochar application reduced temperature-induced injury, especially 50% biochar, which was significantly better than 100% biochar in terms of phenotypic changes, stress physiological index and rhizosphere microbial abundance. First, biochar application prevented the decreases in chlorophyll content, and restrained the increases in relative electrical conductivity, malondialdehyde content and reactive oxygen species. Moreover, four antioxidant enzymes showed increased activation in response to biochar application. Furthermore, biochar application enhanced photosynthesis and maintained intact anatomical structures. Additionally, the related physicochemical properties and soil enzyme activities, together with nitrogen, phosphorus and kalium content of cultivation substrate were improved in response to biochar application, while the rhizosphere microbial abundance was increased, which promoted the root of tree peony to grow. These results revealed that biochar could improve high-temperature tolerance of plants, suggesting that the use of biochar is feasible for enhancing plant growth under high-temperature stress.

Solute-induced grain refinement and defect suppression in boron-modified molybdenum manufactured via laser powder-bed fusion

Molybdenum manufactured with laser powder bed fusion (LPBF) has an undesirable coarse-grained, columnar microstructure interspersed with intergranular cracks, high porosity, and poor mechanical strength. These defects result from a combination of the harsh LPBF process conditions and the disadvantageous properties of molybdenum, such as its high brittle-ductile transition temperature and low tolerance for oxygen impurities. In order to suppress these defect-forming mechanisms and improve the suitability for LPBF, alloy-side material adjustments with simultaneous process optimization are necessary. In this work, the effect of adjusting Mo by adding 3.5 at.% B is investigated experimentally.Mo-3.5 at.% B specimens can be produced entirely free of cracks, with a density of 99.8%. The specimens have a microstructure of fine, equiaxed grains with an average grain size of 31 μm and an aspect ratio of 1.3, thus achieving substantial refinement of the otherwise typically coarse-grained columnar, anisotropic microstructure of pure Mo in LPBF. Furthermore, the grains possess a honeycomb-like cellular subgrain structure. This structure is formed through the solute rejection effect of B during the solidification and consists of initially solidified pure α-Mo cells with a cell size <1 μm and a honeycomb-like network of an ∼100 nm thick intercellular Mo2B phase completely covering the α-Mo cells. In addition, the formation of boron oxide inclusions, presumably B2O3, with a size of <50 nm within the Mo2B phase, provides an effective mechanism for scavenging oxygen impurities, thus ensuring segregation-free grain boundaries in Mo-3.5 at.% B.The microstructural modifications substantially improve the mechanical properties. Under appropriate process conditions, with the substrate plate preheating temperature playing a crucial role, a bending strength of 1120 ± 172 MPa and a hardness of 379 ± 24 HV10 at room temperature can be achieved. At a test temperature of 600 °C, an increase in the bending strength to 2265 MPa is observed, and the bending angle simultaneously increases from 2° at room temperature to 35° at 600 °C. These findings indicate that the strength of Mo-3.5 at.% B is limited by the brittle behavior of the material at lower temperatures, at which residual defects are likely to initiate fracture.

The genomic architecture of high temperature tolerance in a year class of Atlantic Salmon

The yield from fisheries and aquaculture production has risen dramatically over the last few decades, with rising demands to meet the needs of a growing world population that is also consuming more seafood per capita. Aquaculture products have, in recent years, also overtaken tonnage obtained from wild fisheries. This is particularly true for finfish species such as Atlantic salmon. However, the marine lifecycle stage for Atlantic salmon aquaculture requires ocean-based net pens, which introduces environmental vulnerabilities that can negatively affect production. Of particular concern is the ability of the fish to tolerate rising seawater temperatures in the face of climate change. One way of tackling this challenge is to incorporate selective breeding for Atlantic salmon families that display greater tolerance to elevated seawater temperatures. The goal of this study was to determine the genomic heritability of seawater temperature tolerance in Atlantic salmon and to investigate the genetic architecture of this trait for more effective broodstock management. We report a moderate genomic-based heritability for seawater temperature at mortality in Atlantic salmon (0.208 ± 0.041) with a favourable correlation between growth traits (body mass and fork length) and seawater temperature at mortality. Our results also show that seawater temperature at mortality is a polygenic trait, with no significant quantitative trait loci identified. The moderate genomic heritability for seawater temperature at mortality suggests that this trait could be included in Atlantic salmon breeding programs. Importantly, the favourable correlation between growth traits and seawater temperature at mortality suggests that selection for seawater temperature tolerance would not have a negative impact on growth in this population. No single quantitative trait locus for seawater temperature at mortality was identified, suggesting that genomic selection will be required to achieve an increased tolerance to seawater temperature in this population.

LNKs-RVEs complex ticks in the circadian gating of plant temperature stress responses

Recently, Kidokoro et al. found that protein complex LNK3,4-RVE4,8 and LNK1,2-RVE4,8 of the circadian clock modulates plant cold- and high-temperature tolerance, respectively. Here, we reviewed the discovery of LNKs, the dynamically formed morning-phased clock complexes, and their critical role on endogenous circadian rhythms. In addition, we summarized the research work on LNKs with the interacting proteins RVEs, CCA1 in temperature responses and discussed how the circadian clock confer increased fitness via gating the rhythmic expression of their target genes.

High-temperature mechanical behaviors of a WTaRe refractory alloy manufactured by selective electron beam melting

Refractory alloys with their brilliant high-temperature tolerance earn a place for applications in extremely harsh environments. Recent development in additive manufacturing technologies speeds up these alloys' design and forming processes before entering the market. However, the desire for better microstructures and superior high-temperature mechanical behaviors has never been fed up. As was wished, in this study, an additively manufactured WTaRe alloy with compressive strength, ultimate compressive strength, and strain of 356 ± 15 MPa, 731 ± 15 MPa, and > 40% at 1600 °C is herein developed. Composition characterization after deformation of the as-deposited WTaRe alloy suggests the super high thermal stability of this alloy. Considering the excellent high-temperature mechanical behaviors, the printable WTaRe refractory alloy may serve as an alternative in a high-temperature environment.