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Recent global marine lipidomic analysis reveals a strong relationship between ocean temperature and phytoplanktonic abundance of omega-3 long-chain polyunsaturated fatty acids, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are essential for human nutrition and primarily sourced from phytoplankton in marine food webs. In phytoplanktonic organisms, EPA may play a major role in regulating the phase transition temperature of membranes, while the function of DHA remains unexplored. In the oleaginous diatom Phaeodactylum tricornutum, DHA is distributed mainly on extraplastidial phospholipids, which is very different from the EPA enriched in thylakoid lipids. Here, clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9-mediated knockout of delta-5 elongase (ptELO5a), which encodes a delta-5 elongase (ELO5) catalyzing the elongation of EPA to synthesize DHA, led to a substantial interruption of DHA synthesis in P. tricornutum. The ptELO5a mutants showed some alterations in transcriptome and glycerolipidomes, including membrane lipids and triacylglycerols under normal temperature (22 °C), and were more sensitive to elevated temperature (28 °C) than wild type. We conclude that PtELO5a-mediated synthesis of small amounts of DHA has indispensable functions in regulating membrane lipids, indirectly contributing to storage lipid accumulation, and maintaining thermomorphogenesis in P. tricornutum. This study also highlights the significance of DHA synthesis and lipid composition for environmental adaptation of P. tricornutum., Competing Interests: Conflict of interest statement. None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society of Plant Biologists. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

The wide distribution and diverse varieties of chickens make them important models for studying genetic adaptation. The aim of this study was to identify genes that alter heat adaptation in commercial chicken breeds by comparing genetic differences between tropical and cold-resistant chickens. We analyzed whole-genome resequencing data of 186 chickens across various regions in Asia, including the following breeds: Bian chickens (B), Dagu chickens (DG), Beijing-You chickens (BY), and Gallus gallus jabouillei from China; Gallus gallus murghi from India; Vietnam native chickens (VN); Thailand native chickens (TN) and Gallus gallus spadiceus from Thailand; and Indonesia native chickens (IN), Gallus gallus gallus, and Gallus gallus bankiva from Indonesia. In total, 5,454,765 SNPs were identified for further analyses. Population genetic structure analysis revealed that each local chicken breed had undergone independent evolution. Additionally, when K = 5, B, BY, and DG chickens shared a common ancestor and exhibited high levels of inbreeding, suggesting that northern cold-resistant chickens are likely the result of artificial selection. In contrast, the runs of homozygosity (ROH) and the ROH-based genomic inbreeding coefficient (FROH) results for IN, TN, and VN chickens showed low levels of inbreeding. Low population differentiation index values indicated low differentiation levels, suggesting low genetic diversity in tropical chickens, implying increased vulnerability to environmental changes, decreased adaptability, and disease resistance. Whole-genome selection sweep analysis revealed 69 candidate genes, including LGR4, G6PC, and NBR1, between tropical and cold-resistant chickens. The genes were further subjected to GO and KEGG enrichment analyses, revealing that most of the genes were primarily enriched in biological synthesis processes, metabolic processes, central nervous system development, ion transmembrane transport, and the Wnt signaling pathway. Our study identified heat adaptation genes and their functions in chickens that primarily affect chickens in high-temperature environments through metabolic pathways. These heat-resistance genes provide a theoretical basis for improving the heat-adaptation capacity of commercial chicken breeds., Competing Interests: DISCLOSURES This manuscript has not been published or presented elsewhere in part or in entirety and is not under consideration by another journal. The study design was approved by the appropriate ethics review board. We have read and understood your journal's policies, and we believe that neither the manuscript nor the study violates any of these. There are no conflicts of interest to declare., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Climate change poses a significant threat to the sustainability of livestock production systems in developing countries, particularly impacting small ruminants like goats, which are highly susceptible to heat stress. This stressor not only reduces productivity but also undermines economic viability. This study aimed to delve into the molecular mechanisms underlying heat stress tolerance in goats by conducting a comprehensive transcriptome analysis of heat-tolerant (HT, n = 4) and heat-susceptible (HS, n = 6) Jamunapari goats. Physiological metrics, such as rectal temperature, respiratory rate, and heart rate, were meticulously monitored under extreme environmental conditions (Temperature Humidity Index >92) to effectively classify goats based on their distinct heat stress responses. Samples of blood were obtained, and peripheral blood mononuclear cells (PBMCs) were extracted for subsequent RNA extraction. RNA-Seq analysis revealed a sum of 734 differentially expressed genes (DEGs), comprising 251 upregulated and 483 downregulated genes in HT goats compared to their HS counterparts. The WGCNA revealed three key modules, darkorange (tolerance), paleturquoise (respiration rate), and darkmagenta (heart rate). Moreover, functional enrichment analysis revealed that DEGs within these modules played intricate roles in crucial biological processes and pathways, including mitochondrial function, cardiac function, immune response, genomic stability, and metabolic regulation. This research notably enhances our comprehension of the genetic underpinnings of thermo-tolerance in goats and provides invaluable guidance for formulating breeding strategies aimed at bolstering livestock resilience against the challenges of climate change., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The world population is steadily growing, exerting increasing pressure to feed in the future, which would need additional production of major crops. Challenges associated with changing and unpredicted climate (such as heat waves) are causing global food security threats. Cereal crops are a staple food for a large portion of the world's population. They are mostly affected by these environmentally generated abiotic stresses. Therefore, it is imperative to develop climate-resilient cultivars to support the sustainable production of main cereal crops (Rice, wheat, and maize). Among these stresses, heat stress causes significant losses to major cereals. These issues can be solved by comprehending the molecular mechanisms of heat stress and creating heat-tolerant varieties. Different breeding and biotechnology techniques in the last decade have been employed to develop heat-stress-tolerant varieties. However, these time-consuming techniques often lack the pace required for varietal improvement in climate change scenarios. Genome editing technologies offer precise alteration in the crop genome for developing stress-resistant cultivars. CRISPR/Cas9 (Clustered regularly interspaced short palindromic repeat/Cas9), one such genome editing platform, recently got scientists' attention due to its easy procedures. It is a powerful tool for functional genomics as well as crop breeding. This review will focus on the molecular mechanism of heat stress and different targets that can be altered using CRISPR/Cas genome editing tools to generate climate-smart cereal crops. Further, heat stress signaling and essential players have been highlighted to provide a comprehensive overview of the topic., Competing Interests: Declaration of competing interest On behalf of all authors, the corresponding author states that there is no conflict of interest., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Background: Cladocopium infistulum (Symbiodiniaceae) is a dinoflagellate specialized to live in symbiosis with western Pacific giant clams (Tridacnidae). Unlike coral-associated symbionts, which reside within the host cells, C. infistulum inhabits the extracellular spaces of the clam's digestive diverticula. It is phylogenetically basal to a large species complex of stress-tolerant Cladocopium, many of which are associated with important reef-building corals in the genus Porites. This close phylogenetic relationship may explain why C. infistulum exhibits high thermotolerance relative to other tridacnid symbionts. Moreover, past analyses of microsatellite loci indicated that Cladocopium underwent whole-genome duplication prior to the adaptive radiations that led to its present diversity., Results: A draft genome assembly of C. infistulum was produced using long- and short-read sequences to explore the genomic basis for adaptations underlying thermotolerance and extracellular symbiosis among dinoflagellates and to look for evidence of genome duplication. Comparison to three other Cladocopium genomes revealed no obvious over-representation of gene groups or families whose functions would be important for maintaining C. infistulum's unique physiological and ecological properties. Preliminary analyses support the existence of partial or whole-genome duplication among Cladocopium, but additional high-quality genomes are required to substantiate these findings., Conclusion: Although this investigation of Cladocopium infistulum revealed no patterns diagnostic of heat tolerance or extracellular symbiosis in terms of overrepresentation of gene functions or genes under selection, it provided a valuable genomic resource for comparative analyses. It also indicates that ecological divergence among Cladocopium species, and potentially among other dinoflagellates, is partially governed by mechanisms other than gene content. Thus, additional high-quality, multiomic data are needed to explore the molecular basis of key phenotypes among symbiotic microalgae., (© 2024. The Author(s).)

Climate change has been drastically affecting cotton not only in Pakistan but also all over the world. Normally cotton is known as heat tolerant when compared with other crops, but if the high temperature occurs during flowering period the yield decreases significantly. Marker assisted gene pyramiding provides a sustainable solution to improve heat tolerance. A total of seven genotypes were developed by a series of crossing seven tolerant genotypes over the period of three years. Tolerant genotypes were selected by screening for important transcription factors (GHSP26, HSP3, HSFA2, DREB1A, HSP101, DREB2A, GhNAC2, HSPCB, GhWRKY41, TPS, GbMYB5, ANNAT8, GhMPK17, GhMKK1, GhMKK3, GhMPK2, HSC70, APX1 and GhPP2A1). The seven genotypes were evaluated under normal and heat stress in a multi-year trial. The traits related to heat tolerance, such as cell membrane stability, relative water content, excised leaf water loss, plant height, number of nodes, internodal length, number of buds, number of bolls and leaf area was observed under normal and heat stress conditions. The developed genotypes showed improvement in cell membrane stability and relative water content under heat stress. The genotypes [(VH-305×MNH-886)×MNH-1035)×NIAB-78)], [(MNH-1035×MNH-886)×MNH-886)×SM-431] and [(MNH-1035×MNH-886)×MNH-886)×SS-32] depicted heat tolerance and could be used as heat tolerant material for variety development in breeding programs., (© 2024. The Author(s).)

One of the main challenges in coral reef conservation and restoration is the identification of coral populations resilient under global warming. Seascape genomics is a powerful tool to uncover genetic markers potentially involved in heat tolerance among large populations without prior information on phenotypes. Here, we aimed to provide first insights on the role of candidate heat associated loci identified using seascape genomics in driving the phenotypic response of Acropora millepora from New Caledonia to thermal stress. We subjected 7 colonies to a long-term ex-situ heat stress assay (4 °C above the maximum monthly mean) and investigated their physiological response along with their Symbiodiniaceae communities and genotypes. Despite sharing similar thermal histories and associated symbionts, these conspecific individuals differed greatly in their tolerance to heat stress. More importantly, the clustering of individuals based on their genotype at heat-associated loci matched the phenotypic variation in heat tolerance. Colonies that sustained on average lower mortality, higher Symbiodiniaceae/chlorophyll concentrations and photosynthetic efficiency under prolonged heat stress were also the closest based on their genotypes, although the low sample size prevented testing loci predictive accuracy. Together these preliminary results support the relevance of coupling seascape genomics and long-term heat stress experiments in the future, to evaluate the effect size of candidate heat associated loci and pave the way for genomic predictive models of corals heat tolerance., (© 2024. The Author(s).)

Key Message: Key message This study identified stable QTL, promising candidate genes and developed novel KASP markers for heat tolerance, providing genomic resources to assist breeding for the development of high-yielding and heat-tolerant wheat germplasm and varieties. To understand the genetic architecture of eleven agronomic traits under heat stress, we used a doubled-haploid population (177 lines) derived from a heat-sensitive cultivar (PBW343) and a heat-tolerant genotype (KSG1203). This population was evaluated under timely, late and very late sown conditions over locations and years comprising fifteen environments. Best linear unbiased estimates and a genetic map (5,710 SNPs) developed using sequencing-based genotyping were used for QTL mapping. The identified 66 QTL (20 novel) were integrated into wheat physical map (14,263.4 Mb). These QTL explained 5.3% (QDth.ccsu-4A for days to heading and QDtm.ccsu-5B for days to maturity) to 24.9% (QGfd.ccsu-7D for grain filling duration) phenotypic variation. Thirteen stable QTL explaining high phenotypic variation were recommended for marker-assisted recurrent selection (MARS) for optimum/heat stress environments. Selected QTL were validated by their presence in high-yielding doubled-haploid lines. Some QTL for 1000-grain weight (TaERF3-3B, TaFER-5B, and TaZIM-A1), grain yield (TaCol-B5), and developmental traits (TaVRT-2) were co-localized with known genes. Specific known genes for traits like abiotic/biotic stress, grain quality and yield were co-located with 26 other QTL. Furthermore, 209 differentially expressed candidate genes for heat tolerance in plants that encode 28 different proteins were identified. KASP markers for three major/stable QTL, namely QGfd.ccsu-7A for grain filling duration on chromosome 7A (timely sown), QNgs.ccsu-3A for number of grains per spike on 3A, and QDth.ccsu-7A for days to heading on 7A (late and very late sown) environments were developed for MARS focusing on the development of heat-tolerant wheat varieties/germplasm., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Many distantly related organisms have convergently evolved traits and lifestyles that enable them to live in similar ecological environments. However, the extent of phenotypic convergence evolving through the same or distinct genetic trajectories remains an open question. Here, we leverage a comprehensive dataset of genomic and phenotypic data from 1,049 yeast species in the subphylum Saccharomycotina (Kingdom Fungi, Phylum Ascomycota) to explore signatures of convergent evolution in cactophilic yeasts, ecological specialists associated with cacti. We inferred that the ecological association of yeasts with cacti arose independently approximately 17 times. Using a machine learning-based approach, we further found that cactophily can be predicted with 76% accuracy from both functional genomic and phenotypic data. The most informative feature for predicting cactophily was thermotolerance, which we found to be likely associated with altered evolutionary rates of genes impacting the cell envelope in several cactophilic lineages. We also identified horizontal gene transfer and duplication events of plant cell wall-degrading enzymes in distantly related cactophilic clades, suggesting that putatively adaptive traits evolved independently through disparate molecular mechanisms. Notably, we found that multiple cactophilic species and their close relatives have been reported as emerging human opportunistic pathogens, suggesting that the cactophilic lifestyle-and perhaps more generally lifestyles favoring thermotolerance-might preadapt yeasts to cause human disease. This work underscores the potential of a multifaceted approach involving high-throughput genomic and phenotypic data to shed light onto ecological adaptation and highlights how convergent evolution to wild environments could facilitate the transition to human pathogenicity., Competing Interests: JLS is a scientific advisor for WittGen Biotechnologies. JLS is an advisor for ForensisGroup Inc. AR is a scientific consultant for LifeMine Therapeutics, Inc. All other authors have declared that no competing interests exist., (Copyright: © 2024 Gonçalves et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Kelps are vital for marine ecosystems, yet the genetic diversity underlying their capacity to adapt to climate change remains unknown. In this study, we focused on the kelp Macrocystis pyrifera a species critical to coastal habitats. We developed a protocol to evaluate heat stress response in 204 Macrocystis pyrifera genotypes subjected to heat stress treatments ranging from 21 °C to 27 °C. Here we show that haploid gametophytes exhibiting a heat-stress tolerant (HST) phenotype also produced greater biomass as genetically similar diploid sporophytes in a warm-water ocean farm. HST was measured as chlorophyll autofluorescence per genotype, presented here as fluorescent intensity values. This correlation suggests a predictive relationship between the growth performance of the early microscopic gametophyte stage HST and the later macroscopic sporophyte stage, indicating the potential for selecting resilient kelp strains under warmer ocean temperatures. However, HST kelps showed reduced genetic variation, underscoring the importance of integrating heat tolerance genes into a broader genetic pool to maintain the adaptability of kelp populations in the face of climate change., (© 2024. The Author(s).)

Transient heatwaves occurring more frequently as the climate warms, yet their impacts on crop yield are severely underestimated and even overlooked. Heatwaves lasting only a few days or even hours during sensitive stages, such as microgametogenesis and flowering, can significantly reduce crop yield by disrupting plant reproduction. Recent advances in multi-omics and GWAS analysis have shed light on the specific organs (e.g., pollen, lodicule, style), key metabolic pathways (sugar and reactive oxygen species metabolism, Ca 2+ homeostasis), and essential genes that are involved in crop responses to transient heatwaves during sensitive stages. This review therefore places particular emphasis on heat-sensitive stages, with pollen development, floret opening, pollination, and fertilization as the central narrative thread. The multifaceted effects of transient heatwaves and their molecular basis are systematically reviewed, with a focus on key structures such as the lodicule and tapetum. A number of heat-tolerance genes associated with these processes have been identified in major crops like maize and rice. The mechanisms and key heat-tolerance genes shared among different stages may facilitate the more precise improvement of heat-tolerant crops., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Calcium-dependent protein kinase (CDPK) plays a key role in cotton tolerance to abiotic stress. However, its role in cotton heat stress tolerance is not well understood. Here, we characterize the GhCDPK gene family and their expression profiles with the aim of identifying CDPK genes associated with heat stress tolerance., Results: This study revealed 48 GhCDPK members in the cotton genome, distributed on 18 chromosomes. Tree phylogenetic analysis showed three main clustering groups of the GhCDPKs. Cis-elements revealed many abiotic stress and phytohormone pathways conserved promoter regions. Similarly, analysis of the transcription factor binding sites (TFBDS) in the GhCDPK genes showed many stress and hormone related sites. The expression analysis based on qRT-PCR showed that GhCDPK16 was highly responsive to high-temperature stress. Subsequent protein-protein interactions of GhCDPK16 revealed predictable interaction with ROS generating, calcium binding, and ABA signaling proteins. Overexpression of GhCDPK16 in cotton and Arabidopsis improved thermotolerance by lowering ROS compound buildup. Under heat stress, GhCDPK16 transgenic lines upregulated heat-inducible genes GhHSP70, GHSP17.3, and GhGR1, as demonstrated by qRT-PCR analysis. Contrarily, GhCDPK16 knockout lines in cotton exhibited an increase in ROS accumulation. Furthermore, antioxidant enzyme activity was dramatically boosted in the GhCDPK16-ox transgenic lines., Conclusions: The collective findings demonstrated that GhCDPK16 could be a viable gene to enhance thermotolerance in cotton and, therefore, a potential candidate gene for improving heat tolerance in cotton., (© 2024. The Author(s).)

Heat stress (HS) poses a significant challenge to plant survival, necessitating sophisticated molecular mechanisms to maintain cellular homeostasis. Here, we identify SICKLE (SIC) as a key modulator of HS responses in Arabidopsis (Arabidopsis thaliana). SIC is required for the sequestration of RNA DEBRANCHING ENZYME 1 (DBR1), a rate-limiting enzyme of lariat intronic RNA (lariRNA) decay, into stress granules (SGs). The sequestration of DBR1 by SIC enhances the accumulation of lariRNAs, branched circular RNAs derived from excised introns during pre-mRNA splicing, which in turn promote the transcription of their parental genes. Our findings further demonstrate that SIC-mediated DBR1 sequestration in SGs is crucial for plant HS tolerance, as deletion of the N-terminus of SIC (SIC 1-244 ) impairs DBR1 sequestration and compromises plant response to HS. Overall, our study unveils a mechanism of transcriptional regulation in the HS response, where lariRNAs are enriched through DBR1 sequestration, ultimately promoting the transcription of heat stress tolerance genes., (© 2024. The Author(s).)

Heat stress severely restricts the growth and fruit development of apple (Malus domestica). Little is known about the involvement of WRKY proteins in the heat tolerance mechanism in apple. In this study, we found that the apple transcription factor (TF) MdWRKY75 responds to heat and positively regulates basal thermotolerance. Apple plants that overexpressed MdWRKY75 were more tolerant to heat stress while silencing MdWRKY75 caused the opposite phenotype. RNA-seq and reverse transcription quantitative PCR showed that heat shock factor genes (MdHsfs) could be the potential targets of MdWRKY75. Electrophoretic mobility shift, yeast one-hybrid, β-glucuronidase, and dual-luciferase assays showed that MdWRKY75 can bind to the promoters of MdHsf4, MdHsfB2a, and MdHsfA1d and activate their expression. Apple plants that overexpressed MdHsf4, MdHsfB2a, and MdHsfA1d exhibited heat tolerance and rescued the heat-sensitive phenotype of MdWRKY75-Ri3. In addition, apple heat shock cognate 70 (MdHSC70) interacts with MdWRKY75, as shown by yeast two-hybrid, split luciferase, bimolecular fluorescence complementation, and pull-down assays. MdHSC70 acts as a negative regulator of the heat stress response. Apple plants that overexpressed MdHSC70 were sensitive to heat, while virus-induced gene silencing of MdHSC70 enhanced heat tolerance. Additional research showed that MdHSC70 exhibits heat sensitivity by interacting with MdWRKY75 and inhibiting MdHsfs expression. In summary, we proposed a mechanism for the response of apple to heat that is mediated by the "MdHSC70/MdWRKY75-MdHsfs" molecular module, which enhances our understanding of apple thermotolerance regulated by WRKY TFs., Competing Interests: Conflict of interest statement. The authors declare that they have no conflict of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society of Plant Biologists. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

The indica rice variety Huizhan shows elite traits of disease resistance and heat tolerance. However, the underlying genetic basis of these traits is not fully understood due to limited genomic resources. Here, we used Nanopore long-read and next-generation sequencing technologies to generate a chromosome-scale genome assembly of Huizhan. Comparative genomics analysis uncovered a large chromosomal inversion and expanded gene families that are associated with plant growth, development and stress responses. Functional rice blast resistance genes, including Pi2, Pib and Ptr, and bacterial blight resistance gene Xa27, contribute to disease resistance of Huizhan. Furthermore, integrated genomics and transcriptomics analyses showed that OsHIRP1, OsbZIP60, the SOD gene family, and various transcription factors are involved in heat tolerance of Huizhan. The high-quality genome assembly and comparative genomics results presented in this study facilitate the use of Huizhan as an elite parental line in developing rice varieties adapted to disease pressure and climate challenges., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024. Published by Elsevier Inc.)

Recently, elevated seawater temperatures have resulted numerous adverse effects, including significant mortality among bivalves. The dwarf surf clam, Mulinia lateralis, is considered a valuable model species for bivalve research due to its rapid growth and short generation time. The successful cultivation in laboratory setting throughout its entire life cycle makes it an ideal candidate for exploring the potential mechanisms underlying bivalve responses to thermal stress. In this study, a total of 600 clams were subjected to a 17-day thermal stress experiment at a temperature of 30 °C which is the semi-lethal temperature for this species. Ninety individuals who perished initially were classified as heat-sensitive populations (HSP), while 89 individuals who survived the experiment were classified as heat-tolerant populations (HTP). Subsequently, 179 individuals were then sequenced, and 21,292 single nucleotide polymorphisms (SNPs) were genotyped for downstream analysis. The heritability estimate for survival status was found to be 0.375 ± 0.127 suggesting a genetic basis for thermal tolerance trait. Furthermore, a genome-wide association study (GWAS) identified three SNPs and 10 candidate genes associated with thermal tolerance trait in M. lateralis. These candidate genes were involved in the ETHR/EHF signaling pathway and played pivotal role in signal sensory, cell adhesion, oxidative stress, DNA damage repair, etc. Additionally, qPCR results indicated that, excluding MGAT4A, ZAN, and RFC1 genes, all others exhibited significantly higher expression in the HTP (p < 0.05), underscoring the critical involvement of the ETHR/EHF signaling pathway in M. lateralis' thermal tolerance. These results unveil the presence of standing genetic variations associated with thermal tolerance in M. lateralis, highlighting the regulatory role of the ETHR/EHF signaling pathway in the bivalve's response to thermal stress, which contribute to comprehension of the genetic basis of thermal tolerance in bivalves., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

High temperature (HT) severely restricts plant growth, development, and productivity. Plants have evolved a set of mechanisms to cope with HT, including the regulation of heat stress transcription factors (Hsfs) and heat shock proteins (Hsps). However, it is not clear how the transcriptional and translational levels of Hsfs and Hsps are controlled in tomato. Here, we reported that the HT-induced transcription factor SlWRKY55 recruited SlVQ11 to coordinately regulate defense against HT. SlWRKY55 directly bound to the promoter of SlHsfA2 and promoted its expression, which was increased by SlVQ11. Moreover, both SlWRKY55 and SlVQ11 physically interacted with SlHsfA2 to enhance the transcriptional activity of SlHsfA2. Thus, our results revealed a molecular mechanism that the SlWRKY55/SlVQ11-SlHsfA2 cascade enhanced thermotolerance and provided potential target genes for improving the adaptability of crops to HT., (© 2024 Society for Experimental Biology and John Wiley & Sons Ltd.)

The bay scallop is a eurythermal species with high economic value and now represents the most cultured bivalve species in China. Two subspecies of the bay scallop, the northern subspecies Argopecten irradians irradians Korean population (KK) and the southern subspecies Argopecten irradians concentricus (MM), exhibited distinct adaptations to heat stress. However, the molecular mechanism of heat resistance of the two subspecies remains unclear. In this study, we compared the transcriptomic responses of the two subspecies to heat stress and identified the involved differentially expressed genes (DEGs) and pathways. More DEGs were found in the KK than in the MM when exposed to high temperatures, indicating elevated sensitivity to thermal stress in the KK. Enrichment analysis suggests that KK scallops may respond to heat stress more swiftly by regulating GTPase activity. Meanwhile, MM scallops exhibited higher resistance to heat stress mainly by effective activation of their antioxidant system. Chaperone proteins may play different roles in responses to heat stress in the two subspecies. In both subspecies, the expression levels of antioxidants such as GST were significantly increased; the glycolysis process regulated by PC and PCK1 was greatly intensified; and both apoptotic and anti-apoptotic systems were significantly activated. The pathways related to protein translation and hydrolysis, oxidoreductase activity, organic acid metabolism, and cell apoptosis may also play pivotal roles in the responses to heat stress. The results of this study may provide a theoretical basis for marker-assisted breeding of heat-resistant strains., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Global wheat production amounted to >780 MMT during 2022-2023 whose market size are valued at >$128 billion. Wheat is highly susceptible to high-temperature stress (HTS) throughout the life cycle and its yield declines 5-7% with the rise in each degree of temperature. Previously, we reported an array of HTS-response markers from a resilient wheat cv. Unnat Halna and described their putative role in heat acclimation. To complement our previous results and identify the key determinants of thermotolerance, here we examined the cytoplasmic proteome of a sensitive cv. PBW343. The HTS-triggered metabolite reprograming highlighted how proteostasis defects influence the formation of an integrated stress-adaptive response. The proteomic analysis identified several promising HTS-responsive proteins, including a NACα18 protein, designated TaNACα18, whose role in thermotolerance remains unknown. Dual localization of TaNACα18 suggests its crucial functions in the cytoplasm and nucleus. The homodimerization of TaNACα18 anticipated its function as a transcriptional coactivator. The complementation of TaNACα18 in yeast and overexpression in wheat demonstrated its role in thermotolerance across the kingdom. Altogether, our results suggest that TaNACα18 imparts tolerance through tight regulation of gene expression, cell wall remodeling and activation of cell defense responses., (© 2024 Society for Experimental Biology and John Wiley & Sons Ltd.)

This study addresses the critical issue of high-temperature stress in Japanese flounder (Paralichthys olivaceus), a factor threatening both their survival and the growth of the aquaculture industry. The research aims to identify genetic markers associated with high-temperature tolerance, unravel the genetic regulatory mechanisms, and lay the foundation for breeding Japanese flounder with increased resistance to high temperatures. In this study, using a genome-wide association study was performed to identify single nucleotide polymorphisms (SNPs) and genes associated with high-temperature tolerance for Japanese flounder using 280 individuals with 342 311 high-quality SNPs. The traits of high-temperature tolerance were defined as the survival time and survival status of Japanese flounder at high water temperature (31℃) for 15 days cultivate. A genome-wide association study identified six loci on six chromosomes significantly correlated with survival time under high-temperature stress. Six candidate genes were successfully annotated. Additionally, 34 loci associated with survival status were identified and mapped to 15 chromosomes, with 22 candidate genes annotated. Functional analysis highlighted the potential importance of genes like traf4 and ppm1l in regulating apoptosis, impacting high-temperature tolerance in Japanese flounder. These findings provide a valuable theoretical framework for integrating molecular markers into Japanese flounder breeding programmes, serving as a molecular tool to enhance genetic traits linked to high-temperature tolerance in cultured Japanese flounder., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

This study investigated the impact of heat stress on growth and carcass traits in four poultry genotypes-Giriraja, Country chicken, Naked Neck and Kadaknath reared in a hot and humid tropical environment. Birds from all genotypes had ad libitum access to feed and water while being challenged with consistently high environmental temperatures in the experimental shed. Daily diurnal meteorological data were recorded inside and outside the shed. The study specifically examined growth variables and carcass characteristics. Significant differences (p < 0.01) were observed in body weight and average daily gain at various intervals. Notably, feed intake showed significant differences (p < 0.01) across weeks, indicating interactions between genotypes and time intervals. The feed conversion ratio (FCR) varied significantly (p < 0.01), with the highest FCR recorded in the Kadaknath breed. Livability percentages were similar across groups, except for Giriraja, which had significantly lower livability (p < 0.01). Carcass traits, including dressing, wings, feathers and giblet percentages, showed significant differences among genotypes (p < 0.01). Hepatic mRNA expression of growth-related genes revealed numerical variations, with Naked Neck displaying the highest (p < 0.05) fold change in IGF-1 expression compared to other genotypes. The study recognized in the Naked Neck genotype to possess higher resilience in maintaining homoeostasis and uncompromised growth under heat stress, providing valuable insights for sustainable poultry farming in challenging environmental conditions., (© 2024 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.)

Heat stress inhibits plant growth and productivity. Among the main regulators, B-box zinc-finger (BBX) proteins are well-known for their contribution to plant photomorphogenesis and responses to abiotic stress. Our research pinpoints that SlBBX31, a BBX protein harboring a conserved B-box domain, serves as a suppressor of plant growth and heat tolerance in tomato ( Solanum lycopersicum L.). Overexpressing (OE) SlBBX31 in tomato exhibited yellowing leaves due to notable reduction in chlorophyll content and net photosynthetic rate (Pn). Furthermore, the pollen viability of OE lines obviously decreased and fruit bearing was delayed. This not only affected the fruit setting rate and the number of plump seeds but also influenced the size of the fruit. These results indicate that SlBBX31 may be involved in the growth process of tomato, specifically in terms of photosynthesis, flowering, and the fruiting process. Conversely, under heat-stress treatment, SlBBX31 knockout (KO) plants displayed superior heat tolerance, evidenced by their improved membrane stability, heightened antioxidant enzyme activities, and reduced accumulation of reactive oxygen species (ROS). Further transcriptome analysis between OE lines and KO lines under heat stress revealed the impact of SlBBX31 on the expression of genes linked to photosynthesis, heat-stress signaling, ROS scavenging, and hormone regulation. These findings underscore the essential role of SlBBX31 in regulating tomato growth and heat-stress resistance and will provide valuable insights for improving heat-tolerant tomato varieties.

Increasing seawater temperatures coupled with more intense and frequent heatwaves pose an increasing threat to marine species. In this study, the New Zealand green-lipped mussel, Perna canaliculus, was used to investigate the effect of genetics and ontogeny on thermal resilience. The culturally and economically significant mussel P. canaliculus (Gmelin, 1971) has been selectively-bred in New Zealand for two decades, making it a unique biological resource to investigate genetic interactions in a temperate bivalve species. Six selectively-bred full sibling families and four different ages, from early juveniles (6, 8, 10 weeks post-fertilisation) to sub-adults (52 weeks post-fertilisation), were used for experimentation. At each age, each family was exposed to a three-hour heat challenge, followed by recovery, and survival assessments. The shell lengths of live and dead juvenile mussels were also measured. Gill tissue samples from sub-adults were collected after the thermal challenge to quantify the 70 kDa heat shock protein gene (hsp70). Results showed that genetics, ontogeny and size influence thermal resilience in P. canaliculus, with LT 50 values ranging between 31.3 and 34.4 °C for all studied families and ages. Juveniles showed greater thermotolerance compared to sub-adults, while the largest individuals within each family/age class tended to be more heat sensitive than their siblings. Sub-adults differentially upregulated hsp70 in a pattern that correlated with net family survival following heat challenge, reinforcing the perceived role of inducible HSP70 protein in molluscs. This study provides insights into the complex interactions of age and genotype in determining heat tolerance of a key mussel species. As marine temperatures increase, equally complex selection pressure responses may therefore occur. Future research should focus on transcriptomic and genomic approaches for key species such as P. canaliculus to further understand and predict the effect of genetic variation and ontogeny on their survival in the context of climate change., (© 2024. The Author(s).)

The underlying mechanism of thermotolerance, which is a key virulence factor essential for pathogenic fungi such as Cryptococcus neoformans , is largely unexplored. In this study, our findings suggest that Set302, a homolog of Set3 and a subunit of histone deacetylase complex Set3C, contributes to thermotolerance in C. neoformans . Specifically, the deletion of the predicted Set3C core subunit, Set302, resulted in further reduction in the growth of C. neoformans at 39°C, and survival of transient incubation at 50°C. Transcriptomics analysis revealed that the expression levels of numerous heat stress-responsive genes altered at both 30°C and 39°C due to the lack of Set302. Notably, at 39°C, the absence of Set302 led to the downregulation of gene expression related to the ubiquitin-proteasome system (UPS). Based on the GFP-α-synuclein overexpression model to characterize misfolded proteins, we observed a pronounced accumulation of misfolded GFP-α-synuclein at 39°C, consequently inhibiting C. neoformans thermotolerance. Furthermore, the loss of Set302 exacerbated the accumulation of misfolded GFP-α-synuclein during heat stress. Interestingly, the set302∆ strain exhibited a similar phenotype under proteasome stress as it did at 39°C. Moreover, the absence of Set302 led to reduced production of capsule and melanin. set302∆ strain also displayed significantly reduced pathogenicity and colonization ability compared to the wild-type strain in the murine infection model. Collectively, our findings suggest that Set302 modulates thermotolerance by affecting the degradation of misfolded proteins and multiple virulence factors to mediate the pathogenicity of C. neoformans .IMPORTANCE Cryptococcus neoformans is a pathogenic fungus that poses a potential and significant threat to public health. Thermotolerance plays a crucial role in the wide distribution in natural environments and host colonization of this fungus. Herein, Set302, a critical core subunit for the integrity of histone deacetylase complex Set3C and widely distributed in various fungi and mammals, governs thermotolerance and affects survival at extreme temperatures as well as the formation of capsule and melanin in C. neoformans . Additionally, Set302 participates in regulating the expression of multiple genes associated with the ubiquitin-proteasome system (UPS). By eliminating misfolded proteins under heat stress, Set302 significantly contributes to the thermotolerance of C. neoformans . Moreover, Set302 regulates the pathogenicity and colonization ability of C. neoformans in a murine model. Overall, this study provides new insight into the mechanism of thermotolerance in C. neoformans ., Competing Interests: The authors declare no conflict of interest.

How species thrive in a wide range of environments is a major focus of evolutionary biology. For many species, limited genetic diversity or gene flow among habitats means that phenotypic plasticity must play an important role in their capacity to tolerate environmental heterogeneity and to colonize new habitats. However, we have a limited understanding of the molecular components that govern plasticity in ecologically relevant phenotypes. We examined this hypothesis in a spider species (Stegodyphus dumicola) with extremely low species-wide genetic diversity that nevertheless occupies a broad range of thermal environments. We determined phenotypic responses to temperature stress in individuals from four climatic zones using common garden acclimation experiments to disentangle phenotypic plasticity from genetic adaptations. Simultaneously, we created data sets on multiple molecular modalities: the genome, the transcriptome, the methylome, the metabolome, and the bacterial microbiome to determine associations with phenotypic responses. Analyses of phenotypic and molecular associations reveal that acclimation responses in the transcriptome and metabolome correlate with patterns of phenotypic plasticity in temperature tolerance. Surprisingly, genes whose expression seemed to be involved in plasticity in temperature tolerance were generally highly methylated contradicting the idea that DNA methylation stabilizes gene expression. This suggests that the function of DNA methylation in invertebrates varies not only among species but also among genes. The bacterial microbiome was stable across the acclimation period; combined with our previous demonstrations that the microbiome is temporally stable in wild populations, this is convincing evidence that the microbiome does not facilitate plasticity in temperature tolerance. Our results suggest that population-specific variation in temperature tolerance among acclimation temperatures appears to result from the evolution of plasticity in mainly gene expression., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution.)

Raising cattle is a lucrative business that operates globally but is confronted by many obstacles, such as thermal stress, which results in substantial monetary losses. A vital role of heat shock proteins (HSPs) is to protect cells from cellular damage. HSP90 is a highly prevalent, extremely adaptable gene linked to physiological resilience in thermal stress. This study aimed to find genetic polymorphisms of the HSP90AA1 gene in Karan Fries cattle and explore their relationship to thermal tolerance and production traits. One SNP (g.3292 A > C) was found in the Intron 8 and three SNPs loci (g.4776 A > G, g.5218T > C and g.5224 A > C) were found in the exon 11 of 100 multiparous Karan Fries cattle. The association study demonstrated that the SNP1-g.3292 A > C was significantly (P < 0.01) linked to the variables respiratory rate (RR), heat tolerance coefficient (HTC) and total milk yield (TMY (kg)) attributes. There was no significant correlation identified between any of the other SNP sites (SNP2-g.4776 A > G; SNP3-g.5218T > C; SNP4-g.5224 A > C) with the heat tolerance and production attributes in Karan Fries cattle. Haploview 4.2 and SHEsis software programs were used to analyse pair linkage disequilibrium and construct haplotypes for HSP90AA1. Association studies indicated that the Hap3 (CATA) was beneficial for heat tolerance breeding in Karan Fries cattle. In conclusion, genetic polymorphisms and haplotypes in the HSP90AA1 were associated with thermal endurance attributes. This relationship can be utilized as a beneficial SNP or Hap marker for genetic heat resistance selection in cow breeding platforms., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Maize is one of the world's most important staple crops, yet its production is increasingly threatened by the rising frequency of high-temperature stress (HTS). To investigate the genetic basis of anther thermotolerance under field conditions, we performed linkage and association analysis to identify HTS response quantitative trait loci (QTL) using three recombinant inbred line (RIL) populations and an association panel containing 375 diverse maize inbred lines. These analyses resulted in the identification of 16 co-located large QTL intervals. Among the 37 candidate genes identified in these QTL intervals, five have rice or Arabidopsis homologs known to influence pollen and filament development. Notably, one of the candidate genes, ZmDUP707, has been subject to selection pressure during breeding. Its expression is suppressed by HTS, leading to pollen abortion and barren seeds. We also identified several additional candidate genes potentially underly QTL previously reported by other researchers. Taken together, our results provide a pool of valuable candidate genes that could be employed by future breeding programs aiming at enhancing maize HTS tolerance., (© 2024 Society for Experimental Biology and John Wiley & Sons Ltd.)

Epigenetic variations result from long-term adaptation to environmental factors. The Bos indicus (zebu) adapted to tropical conditions, whereas Bos taurus adapted to temperate conditions; hence native zebu cattle and its crossbred (B indicus × B taurus) show differences in responses to heat stress. The present study evaluated genome-wide DNA methylation profiles of these two breeds of cattle that may explain distinct heat stress responses. Physiological responses to heat stress and estimated values of Iberia heat tolerance coefficient and Benezra's coefficient of adaptability revealed better relative thermotolerance of Hariana compared to the Vrindavani cattle. Genome-wide DNA methylation patterns were different for Hariana and Vrindavani cattle. The comparison between breeds indicated the presence of 4599 significant differentially methylated CpGs with 756 hypermethylated and 3845 hypomethylated in Hariana compared to the Vrindavani cattle. Further, we found 79 genes that showed both differential methylation and differential expression that are involved in cellular stress response functions. Differential methylations in the microRNA coding sequences also revealed their functions in heat stress responses. Taken together, epigenetic differences represent the potential regulation of long-term adaptation of Hariana (B indicus) cattle to the tropical environment and relative thermotolerance., Competing Interests: Declarations of interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Basavaraj Sajjanar reports financial support was provided by SERB-DST Government of India. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

With glossy, wax-coated leaves, Rubus leucanthus is one of the few heat-tolerant wild raspberry trees. To ascertain the underlying mechanism of heat tolerance, we generated a high-quality genome assembly with a genome size of 230.9 Mb and 24,918 protein-coding genes. Significantly expanded gene families were enriched in the flavonoid biosynthesis pathway and the circadian rhythm-plant pathway, enabling survival in subtropical areas by accumulating protective flavonoids and modifying photoperiodic responses. In contrast, plant-pathogen interaction and MAPK signaling involved in response to pathogens were significantly contracted. The well-known heat response elements (HSP70, HSP90, and HSFs) were reduced in R. leucanthus compared to two other heat-intolerant species, R. chingii and R. occidentalis, with transcriptome profiles further demonstrating their dispensable roles in heat stress response. At the same time, three significantly positively selected genes in the pathway of cuticular wax biosynthesis were identified, and may contribute to the glossy, wax-coated leaves of R. leucanthus. The thick, leathery, waxy leaves protect R. leucanthus against pathogens and herbivores, supported by the reduced R gene repertoire in R. leucanthus (355) compared to R. chingii (376) and R. occidentalis (449). Our study provides some insights into adaptive divergence between R. leucanthus and other raspberry species on heat tolerance., (© The Author(s) 2024. Published by Oxford University Press on behalf of Kazusa DNA Research Institute.)

Heat stress is an environmental factor that significantly threatens crop production worldwide. Nevertheless, the molecular mechanisms governing plant responses to heat stress are not fully understood. Plant zinc finger CCCH proteins have roles in stress responses as well as growth and development through protein-RNA, protein-DNA, and protein-protein interactions. Here, we reveal an integrated multi-level regulation of plant thermotolerance that is mediated by the CCCH protein C3H15 in Arabidopsis. Heat stress rapidly suppressed C3H15 transcription, which attenuated C3H15-inhibited expression of its target gene HEAT SHOCK TRANSCRIPTION FACTOR A2 (HSFA2), a central regulator of heat stress response (HSR), thereby activating HEAT SHOCK COGNATE 70 (HSC70.3) expression. The RING-type E3 ligase MED25-BINDING RING-H2 PROTEIN 2 (MBR2) was identified as an interacting partner of C3H15. The mbr2 mutant was susceptible to heat stress compared to wild-type plants, whereas plants overexpressing MBR2 showed increased heat tolerance. MBR2-dependent ubiquitination mediated the degradation of phosphorylated C3H15 protein in the cytoplasm, which was enhanced by heat stress. Consistently, heat sensitivities of C3H15 overexpression lines increased in MBR2 loss-of-function and decreased in MBR2 overexpression backgrounds. Heat stress-induced accumulation of HSC70.3 promoted MBR2-mediated degradation of C3H15 protein, implying that an auto-regulatory loop involving C3H15, HSFA2, and HSC70.3 regulates HSR. Heat stress also led to the accumulation of C3H15 in stress granules (SGs), a kind of cytoplasmic RNA granule. This study advances our understanding of the mechanisms plants use to respond to heat stress, which will facilitate technologies to improve thermotolerance in crops., (© 2024 Society for Experimental Biology and John Wiley & Sons Ltd.)

Petunia hybrida, widely grown as a bedding plant, has reduced growth and flower quality at temperatures above 30 °C (heat stress), primarily due to heat stress-induced ethylene (ET) production. The gene acdS encodes the 1-aminocyclopropane-1-carboxylate (ACC) deaminase (ACCD) enzyme, which is known for its role in reducing ET production by breaking down the ET precursor, ACC, in plant tissues. This study investigated the impact of heat stress on both 'Mirage Rose' WT petunia and its acdS-overexpressing transgenic lines. Heat stress-induced growth inhibition was observed in WT plants but not in transgenic plants. The increased stress tolerance of transgenic plants over WT plants was associated with lower ET production, ROS accumulation, higher SPAD values, water content, and relative water content. Furthermore, higher sensitivity of the WT to heat stress than the transgenic plants was confirmed by analysing ET signalling genes, heat shock transcription factor genes, and antioxidant- and proline-related genes, more strongly induced in WT than in transgenic plants. Overall, this study suggests the potential application of acdS overexpression in other floriculture plants as a viable strategy for developing heat stress-tolerant varieties. This approach holds promise for advancing the floricultural industry by overcoming challenges related to heat-induced growth inhibition and loss of flower quality., (© 2024 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.)

Main Conclusion: The SpHsfA8a upregulated expression can induce the expression of multiple heat-tolerance genes, and increase the tolerance of Arabidopsis thaliana to high-temperature stress. Sorbus pohuashanensis is an ornamental tree used in courtyards. However, given its poor thermotolerance, the leaves experience sunburn owing to high temperatures in summer, severely affecting its ornamental value. Heat-shock transcription factors play a critical regulatory role in the plant response to heat stress. To explore the heat-tolerance-related genes of S. pohuashanensis to increase the tree's high-temperature tolerance, the SpHsfA8a gene was cloned from S. pohuashanensis, and its structure and expression patterns in different tissues and under abiotic stress were analyzed, as well as its function in heat tolerance, was determined via overexpression in Arabidopsis thaliana. The results showed that SpHsfA8a encodes 416 amino acids with a predicted molecular weight of 47.18 kDa and an isoelectric point of 4.63. SpHsfA8a is a hydrophilic protein without a signal peptide and multiple phosphorylation sites. It also contains a typical DNA-binding domain and is similar to MdHsfA8a in Malus domestica and PbHsfA8 in Pyrus bretschneideri. In S. pohuashanensis, SpHsfA8a is highly expressed in the roots and fruits and is strongly induced under high-temperature stress in leaves. The heterologous expression of SpHsfA8a in A. thaliana resulted in a considerably stronger growth status than that of the wild type after 6 h of treatment at 45 °C. Its proline content, catalase and peroxidase activities also significantly increased, indicating that the SpHsfA8a gene increased the tolerance of A. thaliana to high-temperature stress. SpHsfA8a could induce the expression of multiple heat-tolerance genes in A. thaliana, indicating that SpHsfA8a could strengthen the tolerance of A. thaliana to high-temperature stress through a complex regulatory network. The results of this study lay the foundation for further elucidation of the regulatory mechanism of SpHsfA8a in response of S. pohuashanensis to high-temperature stress., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Climate change, particularly drought and heat stress, may slash agricultural productivity by 25.7% by 2080, with maize being the hardest hit. Therefore, unraveling the molecular nature of plant responses to these stressors is vital for the development of climate-smart maize. This manuscript's primary objective was to examine how maize plants respond to these stresses, both individually and in combination. Additionally, the paper delved into harnessing the potential of maize wild relatives as a valuable genetic resource and leveraging AI-based technologies to boost maize resilience. The role of multiomics approaches particularly genomics and transcriptomics in dissecting the genetic basis of stress tolerance was also highlighted. The way forward was proposed to utilize a bunch of information obtained through omics technologies by an interdisciplinary state-of-the-art forward-looking big-data, cyberagriculture system, and AI-based approach to orchestrate the development of climate resilient maize genotypes.

The algal endosymbiont Durusdinium trenchii enhances the resilience of coral reefs under thermal stress. D. trenchii can live freely or in endosymbiosis, and the analysis of genetic markers suggests that this species has undergone whole-genome duplication (WGD). However, the evolutionary mechanisms that underpin the thermotolerance of this species are largely unknown. Here, we present genome assemblies for two D. trenchii isolates, confirm WGD in these taxa, and examine how selection has shaped the duplicated genome regions using gene expression data. We assess how the free-living versus endosymbiotic lifestyles have contributed to the retention and divergence of duplicated genes, and how these processes have enhanced the thermotolerance of D. trenchii . Our combined results suggest that lifestyle is the driver of post-WGD evolution in D. trenchii , with the free-living phase being the most important, followed by endosymbiosis. Adaptations to both lifestyles likely enabled D. trenchii to provide enhanced thermal stress protection to the host coral.

Transcription factors (TFs) play a crucial role in gene expression, and studying them can lay the foundation for future research on the functional characterization of TFs involved in various biological processes. In this study, we conducted a genome-wide identification and analysis of TFs in the thermotolerant basidiomycete fungus, Coriolopsis trogii. The TF repertoire of C. trogii consisted of 350 TFs, with C2H2 and Zn2C6 being the largest TF families. When the mycelia of C. trogii were cultured on PDA and transferred from 25 to 35 °C, 14 TFs were up-regulated and 14 TFs were down-regulated. By analyzing RNA-seq data from mycelia cultured at different temperatures and under different carbon sources, we identified 22 TFs that were differentially expressed in more than three comparisons. Co-expression analysis revealed that seven differentially expressed TFs, including four Zn2C6s, one Hap4&#95;Hap&#95;bind, one HMG&#95;box, and one Zinc&#95;knuckle, showed significant correlation with 729 targeted genes. Overall, this study provides a comprehensive characterization of the TF family and systematically screens TFs involved in the high-temperature adaptation of C. trogii, laying the groundwork for further research into the specific roles of TFs in the heat tolerance mechanisms of filamentous fungi., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Multiprotein bridging factor 1 (MBF1) is a very important transcription factor (TF) in plants, whose members influence numerous defense responses. Our study found that MBF1c in Cucurbitaceae was highly conserved. CsMBF1c expression was induced by temperature, salt stress, and abscisic acid (ABA) in cucumber. Overexpressed CsMBF1c enhanced the heat resistance of a cucumber, and the Csmbf1c mutant showed decreased resistance to high temperatures (HTs). CsMBF1c played an important role in stabilizing the photosynthetic system of cucumber under HT, and its expression was significantly associated with heat-related TFs and genes related to protein processing in the endoplasmic reticulum (ER). Protein interaction showed that CsMBF1c interacted with dehydration-responsive element binding protein 2 (CsDREB2) and nuclear factor Y A1 (CsNFYA1). Overexpression of CsNFYA1 in Arabidopsis improved the heat resistance. Transcriptional activation of CsNFYA1 was elevated by CsMBF1c. Therefore, CsMBF1c plays an important regulatory role in cucumber's resistance to high temperatures.

Drought and heat are major abiotic stresses frequently coinciding to threaten rice production. Despite hundreds of stress-related genes being identified, only a few have been confirmed to confer resistance to multiple stresses in crops. Here we report ONAC023, a hub stress regulator that integrates the regulations of both drought and heat tolerance in rice. ONAC023 positively regulates drought and heat tolerance at both seedling and reproductive stages. Notably, the functioning of ONAC023 is obliterated without stress treatment and can be triggered by drought and heat stresses at two layers. The expression of ONAC023 is induced in response to stress stimuli. We show that overexpressed ONAC23 is translocated to the nucleus under stress and evidence from protoplasts suggests that the dephosphorylation of the remorin protein OSREM1.5 can promote this translocation. Under drought or heat stress, the nuclear ONAC023 can target and promote the expression of diverse genes, such as OsPIP2;7, PGL3, OsFKBP20-1b, and OsSF3B1, which are involved in various processes including water transport, reactive oxygen species homeostasis, and alternative splicing. These results manifest that ONAC023 is fine-tuned to positively regulate drought and heat tolerance through the integration of multiple stress-responsive processes. Our findings provide not only an underlying connection between drought and heat responses, but also a promising candidate for engineering multi-stress-resilient rice., (© 2024. The Author(s).)

Background: Heat stress is a detrimental abiotic stress that limits the development of many plant species and is linked to a variety of cellular and physiological problems. Heat stress affects membrane fluidity, which leads to negative effects on cell permeability and ion transport. Research reveals that heat stress causes severe damage to cells and leads to rapid accumulation of reactive oxygen species (ROS), which could cause programmed cell death., Methods and Results: This current study aimed to validate the role of Triticum aestivum Salt Stress Root Protein (TaSSRP) in plants' tolerance to heat stress by modulating its expression in tobacco plants. The Relative Water Content (RWC), total chlorophyll content, and Membrane Stability Index (MSI) of the seven distinct transgenic lines (T 0 - 2 , T 0 - 3 , T 0 - 6 , T 0 - 8 , T 0 - 9 , T 0 - 11 , and T 0 - 13 ), increased in response to heat stress. Despite the fact that the same tendency was detected in wild-type (WT) plants, changes in physio-biochemical parameters were greater in transgenic lines than in WT plants. The expression analysis revealed that the transgene TaSSRP expressed from 1.00 to 1.809 folds in different lines in the transgenic tobacco plants. The gene TaSSRP offered resistance to heat stress in Nicotiana tabacum, according to the results of the study., Conclusion: These findings could help to improve our knowledge and understanding of the mechanism underlying thermotolerance in wheat, and the novel identified gene TaSSRP could be used in generating wheat varieties with enhanced tolerance to heat stress., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Temperature shapes the geographical distribution and behavior of plants. Understanding the regulatory mechanisms underlying the plant heat stress response is important for developing climate-resilient crops, including maize (Zea mays). To identify transcription factors (TFs) that may contribute to the maize heat stress response, we generated a dataset of short- and long-term transcriptome changes following a heat treatment time course in the inbred line B73. Co-expression network analysis highlighted several TFs, including the class B2a heat shock factor (HSF) ZmHSF20. Zmhsf20 mutant seedlings exhibited enhanced tolerance to heat stress. Furthermore, DNA affinity purification sequencing and Cleavage Under Targets and Tagmentation assays demonstrated that ZmHSF20 binds to the promoters of Cellulose synthase A2 (ZmCesA2) and three class A Hsf genes, including ZmHsf4, repressing their transcription. We showed that ZmCesA2 and ZmHSF4 promote the heat stress response, with ZmHSF4 directly activating ZmCesA2 transcription. In agreement with the transcriptome analysis, ZmHSF20 inhibited cellulose accumulation and repressed the expression of cell wall-related genes. Importantly, the Zmhsf20 Zmhsf4 double mutant exhibited decreased thermotolerance, placing ZmHsf4 downstream of ZmHsf20. We proposed an expanded model of the heat stress response in maize, whereby ZmHSF20 lowers seedling heat tolerance by repressing ZmHsf4 and ZmCesA2, thus balancing seedling growth and defense., Competing Interests: Conflict of interest statement. The authors declare no conflict of interests., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society of Plant Biologists.)

Heat stress is one of the primary environmental factors that harm both the productivity and health of buffaloes. The current study was conducted to estimate the threshold of temperature humidity index (THI) 1 and genetic features for milk yield of first-lactation Mehsana buffaloes using an univariate repeatability test-day model. The data included 130,475 first lactation test-day milk yield (FLTDMY) records of 13,887 Mehsana buffaloes and the daily temperature and humidity. The statistical model included herd test day as fixed effects, days-in-milk (DIM) classes, age of the animal, as well as random factors such as the additive genetic effect (AGE) of animal in general conditions (intercept), AGE of the buffaloes subjected to heat stress (slope), permanent environmental effect of animal in general conditions (intercept), permanent environmental effect of animal under heat stress conditions (slope) and random residual effect. It was expected that the general effects and the heat-tolerance effects would be correlated, represented by the present investigation's repeatability models. The variance components of FLTDMY in the present study were computed using the REML method. The threshold for THI was 78. At the THI below the threshold, the heritability estimated for the FLTDMY trait was 0.29, and the additive genetic variance (AGV) for heat stress conditions was 0. At THI of 83, AGV for heat stress conditions was highest for FLTDMY. The genetic correlation of general AGE to heat-tolerant AGE was -0.40. The results indicated that a consistent selection for milk production, avoiding the thermal tolerance, may diminish the thermal tolerance capacity of Mehsana buffaloes., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Global warming has a severe impact on the flowering time and yield of crops. Histone modifications have been well-documented for their roles in enabling plant plasticity in ambient temperature. However, the factor modulating histone modifications and their involvement in habitat adaptation have remained elusive. In this study, through genome-wide pattern analysis and quantitative-trait-locus (QTL) mapping, we reveal that BrJMJ18 is a candidate gene for a QTL regulating thermotolerance in thermotolerant B. rapa subsp. chinensis var. parachinensis (or Caixin, abbreviated to Par). BrJMJ18 encodes an H3K36me2/3 Jumonji demethylase that remodels H3K36 methylation across the genome. We demonstrate that the BrJMJ18 allele from Par (BrJMJ18 Par ) influences flowering time and plant growth in a temperature-dependent manner via characterizing overexpression and CRISPR/Cas9 mutant plants. We further show that overexpression of BrJMJ18 Par can modulate the expression of BrFLC3, one of the five BrFLC orthologs. Furthermore, ChIP-seq and transcriptome data reveal that BrJMJ18 Par can regulate chlorophyll biosynthesis under high temperatures. We also demonstrate that three amino acid mutations may account for function differences in BrJMJ18 between subspecies. Based on these findings, we propose a working model in which an H3K36me2/3 demethylase, while not affecting agronomic traits under normal conditions, can enhance resilience under heat stress in Brassica rapa., (© 2024. The Author(s).)

Autophagy, a highly conserved protein degradation system, plays an important role in protecting cells from adverse environmental conditions. ATG8-INTERACTING PROTEIN1 (ATI1) acts as an autophagy receptor, but its functional mechanisms in plants' heat stress tolerance remain unclear. In this study, using LC-MS/MS, we identified malate dehydrogenase (SlMDH3) as a SlATI1-interacting protein. Further studies showed that heat stress induced the expression of SlMDH3 and SlMDH3 co-localized with SlATI1 under both 22 °C and 42 °C heat treatment conditions. Moreover, silencing of SlMDH3 increased the sensitivity of tomato to heat stress, as evidenced by exacerbated degradation of chlorophyll; accumulation of MDA, H 2 O 2 , and dead cells; increased relative conductivity; and inhibition of stress-related gene expression. Conversely, overexpression of SlMDH3 improved tomato's heat tolerance, leading to opposite effects on physiological indicators and gene expression compared to SlMDH3 silencing. Taken together, our study suggests that SlMDH3 interacts with SlATI1 and positively regulates tomato heat tolerance.

Heat shock transcription factors (HSFs) play a crucial role in heat stress tolerance in vegetative tissues. However, their involvement in reproductive tissues and their post-translational modifications are not well understood. In this study, we identify the E3 ligase XB3 ORTHOLOG 1 IN ARABIDOPSIS THALIANA (XBAT31) as a key player in the ubiquitination and degradation of HSFB2a/B2b. Our results show that the xbat31 mutant exhibits a higher percentage of unfertile siliques and decreased expression of HSPs in flowers under heat stress conditions compared to the wild type. Conversely, the hsfb2a hsfb2b double mutant displays improved reproductive thermotolerance. We find that XBAT31 interacts with HSFB2a/B2b and mediates their ubiquitination. Furthermore, HSFB2a/B2b ubiquitination is reduced in the xbat31-1 mutant, resulting in higher accumulation of HSFB2a/B2b in flowers under heat stress conditions. Overexpression of HSFB2a or HSFB2b leads to an increase in unfertile siliques under heat stress conditions. Thus, our results dissect the important role of the XBAT31-HSFB2a/B2b module in conferring reproductive thermotolerance in plants., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

High temperatures are a major stress factor that limit the growth of Pinellia ternata. WRKY proteins widely distribute in plants with the important roles in plant growth and stress responses. However, WRKY genes have not been identified in P. ternata thus far. In this study, five PtWRKYs with four functional subgroups were identified in P. ternata. One group III WRKY transcription factor, PtWRKY2, was strongly induced by high temperatures, whereas the other four PtWRKYs were suppressed. Analysis of transcription factor characteristics revealed that PtWRKY2 localized to the nucleus and specifically bound to W-box elements without transcriptional activation activity. Overexpression of PtWRKY2 increased the heat tolerance of Arabidopsis, as shown by the higher percentage of seed germination and survival rate, and the longer root length of transgenic lines under high temperatures compared to the wild-type. Moreover, PtWRKY2 overexpression significantly decreased reactive oxygen species accumulation by increasing the catalase, superoxide dismutase, and peroxidase activities. Furthermore, the selected heat shock-associated genes, including five transcription factors (HSFA1A, HSFA7A, bZIP28, DREB2A, and DREB2B), two heat shock proteins (HSP70 and HSP17.4), and three antioxidant enzymes (POD34, CAT1, and SOD1), were all upregulated in transgenic Arabidopsis. The study identifies that PtWRKY2 functions as a key transcriptional regulator in the heat tolerance of P. ternata, which might provide new insights into the genetic improvement of P. ternata., (© 2024. The Author(s).)

Aegilops tauchii is a D-genome donor of hexaploid wheat and is a potential source of genes for various biotic and abiotic stresses including heat and drought. In the present study, we used multi-stage evaluation technique to understand the effects of heat and drought stresses on Ae. tauschii derived introgression lines (ILs). Preliminary evaluation (during stage-I) of 369 ILs for various agronomic traits identified 59 agronomically superior ILs. In the second stage (stage-II), selected ILs ( i.e. , 59 ILs) were evaluated for seedling heat (at 30 °C and 35 °C) and drought (at 20% poly-ethylene glycol; PEG) stress tolerance under growth chambers (stage-II). Heat and drought stress significantly reduced the seedling vigour by 59.29 and 60.37 percent, respectively. Genotype × treatment interaction analysis for seedling vigour stress tolerance index (STI) identified IL-50, IL-56, and IL-68 as high-performing ILs under heat stress and IL-42 and IL-44 as high-performing ILs under drought stress. It also revealed IL-44 and IL-50 as the stable ILs under heat and drought stresses. Furthermore, in the third stage (stage-III), selected ILs were evaluated for heat and drought stress tolerance under field condition over two cropping seasons (viz., 2020-21 and 2021-22), which significantly reduced the grain yield by 72.79 and 48.70 percent, respectively. Stability analysis was performed to identify IL-47, IL-51, and IL-259 as the most stable ILs in stage-III. Tolerant ILs with specific and wider adaptability identified in this study can serve as the potential resources to understand the genetic basis of heat and drought stress tolerance in wheat and they can also be utilized in developing high-yielding wheat cultivars with enhanced heat and drought stress tolerance., Competing Interests: Diaa Abd El-Moneim is an Academic Editor for PeerJ., (©2024 Gudi et al.)

Key Message: Our findings highlight a valuable breeding resource, demonstrating the potential to concurrently enhance grain shape, thermotolerance, and alkaline tolerance by manipulating Gγ protein in rice. Temperate Geng/Japonica (GJ) rice yields have improved significantly, bolstering global food security. However, GJ rice breeding faces challenges, including enhancing grain quality, ensuring stable yields at warmer temperatures, and utilizing alkaline land. In this study, we employed CRISPR/Cas9 gene-editing technology to knock out the GS3 locus in seven elite GJ varieties with superior yield performance. Yield component measurements revealed that GS3 knockout mutants consistently enhanced grain length and reduced plant height in diverse genetic backgrounds. The impact of GS3 on the grain number per panicle and setting rate depended on the genetic background. GS3 knockout did not affect milling quality and minimally altered protein and amylose content but notably influenced chalkiness-related traits. GS3 knockout indiscriminately improved heat and alkali stress tolerance in the GJ varieties studied. Transcriptome analysis indicated differential gene expression between the GS3 mutants and their wild-type counterparts, enriched in biological processes related to photosynthesis, photosystem II stabilization, and pathways associated with photosynthesis and cutin, suberine, and wax biosynthesis. Our findings highlight GS3 as a breeding resource for concurrently improving grain shape, thermotolerance, and alkaline tolerance through Gγ protein manipulation in rice., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Climate change is resulting in more frequent and rapidly changing temperatures at both extremes that severely affect the growth and production of plants, particularly crops. Oxidative stress caused by high temperatures is one of the most damaging factors for plants. However, the role of hydrogen peroxide (H 2 O 2 ) in modulating plant thermotolerance is largely unknown, and the regulation of photorespiration essential for C3 species remains to be fully clarified. Here, we report that heat stress promotes H 2 O 2 accumulation in chloroplasts and that H 2 O 2 stimulates sulfenylation of the chloroplast-localized photorespiratory enzyme 2-phosphoglycolate phosphatase 1 (PGLP1) at cysteine 86, inhibiting its activity and promoting the accumulation of the toxic metabolite 2-phosphoglycolate. We also demonstrate that PGLP1 has a positive function in plant thermotolerance, as PGLP1 antisense lines have greater heat sensitivity and PGLP1-overexpressing plants have higher heat-stress tolerance than the wild type. Together, our results demonstrate that heat-induced H 2 O 2 in chloroplasts sulfenylates and inhibits PGLP1 to modulate plant thermotolerance. Furthermore, targeting CATALASE2 to chloroplasts can largely prevent the heat-induced overaccumulation of H 2 O 2 and the sulfenylation of PGLP1, thus conferring thermotolerance without a plant growth penalty. These findings reveal that heat-induced H 2 O 2 in chloroplasts is important for heat-caused plant damage., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Zea mays (maize) is a staple food, feed, and industrial crop. Heat stress is one of the major stresses affecting maize production and is usually accompanied by other stresses, such as drought. Our previous study identified a heterotrimer complex, ZmNF-YA1-YB16-YC17, in maize. ZmNF-YA1 and ZmNF-YB16 were positive regulators of the drought stress response and were involved in maize root development. In this study, we investigated whether ZmNF-YA1 confers heat stress tolerance in maize. The nf-ya1 mutant and overexpression lines were used to test the role of ZmNF-YA1 in maize thermotolerance. The nf-ya1 mutant was more temperature-sensitive than the wild-type (WT), while the ZmNF-YA1 overexpression lines showed a thermotolerant phenotype. Higher malondialdehyde (MDA) content and reactive oxygen species (ROS) accumulation were observed in the mutant, followed by WT and overexpression lines after heat stress treatment, while an opposite trend was observed for chlorophyll content. RNA-seq was used to analyze transcriptome changes in nf-ya1 and its wild-type control W22 in response to heat stress. Based on their expression profiles, the heat stress response-related differentially expressed genes (DEGs) in nf-ya1 compared to WT were grouped into seven clusters via k -means clustering. Gene Ontology (GO) enrichment analysis of the DEGs in different clades was performed to elucidate the roles of ZmNF-YA1-mediated transcriptional regulation and their contribution to maize thermotolerance. The loss function of ZmNF-YA1 led to the failure induction of DEGs in GO terms of protein refolding, protein stabilization, and GO terms for various stress responses. Thus, the contribution of ZmNF-YA1 to protein stabilization, refolding, and regulation of abscisic acid (ABA), ROS, and heat/temperature signaling may be the major reason why ZmNF-YA1 overexpression enhanced heat tolerance, and the mutant showed a heat-sensitive phenotype.

Coral populations must be able to adapt to changing environmental conditions for coral reefs to persist under climate change. The adaptive potential of these organisms is difficult to forecast due to complex interactions between the host animal, dinoflagellate symbionts and the environment. Here we created 26 larval families from six Montipora capitata colonies from a single reef, showing significant, heritable variation in thermal tolerance. Our results indicate that 9.1% of larvae are expected to exhibit four times the thermal tolerance of the general population. Differences in larval thermotolerance were driven mainly by maternal contributions, but we found no evidence that these effects were driven by symbiont identity despite vertical transmission from the dam. We also document no evidence of reproductive incompatibility attributable to symbiont identity. These data demonstrate significant genetic variation within this population which provides the raw material upon which natural selection can act., (© 2024. The Author(s), under exclusive licence to The Genetics Society.)

Coping with stressful conditions and maintaining reproduction are two key biological processes that affect insect population dynamics. Small heat shock proteins (sHSPs) are involved in the stress response and the development of insects. The sHsp gene Laodelphax striatellus (Hemiptera: Delphacidae) sHsp 21.5 (LsHsp21.5) showed constitutive, stage- and organ-specific expression in L. striatellus, a pest that damages cultivated rice in east Asia. The expression of LsHsp21.5 was highest in the ovary, with 43.60, 12.99 and 1.45 time higher expression here than in the head, gut and female fat bodies, respectively. The expression of this gene was weakly affected by heat or cold shock. The gene provided in vitro protection against heat damage to malate dehydrogenase and in vivo protection against heat stress in Escherichia coli (Enterobacteriales: Enterobacteriaceae) BL21(DE3) and L. striatellus. Moreover, L. striatellus reproduction decreased by 1.85 times when the expression of LsHsp21.5 was inhibited by RNA interference. The expression of some genes related to reproduction, such as the homologous gene of chorion protein, also declined. These results suggest that LsHsp21.5 expression not only protects other proteins against stress but also helps maintain the stable expression of some reproduction-related genes under non-stressful conditions, with impacts on L. striatellus fecundity., (© 2024 Royal Entomological Society.)