Genome-wide identification, classification and expression analysis of the heat shock transcription factor family in Garlic (Allium sativum L.).

BACKGROUND: The heat shock transcription factor (HSF) plays a crucial role in the regulatory network by coordinating responses to heat stress as well as other stress signaling pathways. Despite extensive studies on HSF functions in various plant species, our understanding of this gene family in garlic, an important crop with nutritional and medicinal value, remains limited. In this study, we conducted a comprehensive investigation of the entire garlic genome to elucidate the characteristics of the AsHSF gene family. RESULTS: In this study, we identified a total of 17 AsHSF transcription factors. Phylogenetic analysis classified these transcription factors into three subfamilies: Class A (9 members), Class B (6 members), and Class C (2 members). Each subfamily was characterized by shared gene structures and conserved motifs. The evolutionary features of the AsHSF genes were investigated through a comprehensive analysis of chromosome location, conserved protein motifs, and gene duplication events. These findings suggested that the evolution of AsHSF genes is likely driven by both tandem and segmental duplication events. Moreover, the nucleotide diversity of the AsHSF genes decreased by only 0.0002% from wild garlic to local garlic, indicating a slight genetic bottleneck experienced by this gene family during domestication. Furthermore, the analysis of cis-acting elements in the promoters of AsHSF genes indicated their crucial roles in plant growth, development, and stress responses. qRT-PCR analysis, co-expression analysis, and protein interaction prediction collectively highlighted the significance of Asa6G04911. Subsequent experimental investigations using yeast two-hybridization and yeast induction experiments confirmed its interaction with HSP70/90, reinforcing its significance in heat stress. CONCLUSIONS: This study is the first to unravel and analyze the AsHSF genes in garlic, thereby opening up new avenues for understanding their functions. The insights gained from this research provide a valuable resource for future investigations, particularly in the functional analysis of AsHSF genes.

Genome-Wide Analysis of the HSF Gene Family Reveals Its Role in Astragalus mongholicus under Different Light Conditions.

Astragalus mongholicus is a traditional Chinese medicine (TCM) with important medicinal value and is widely used worldwide. Heat shock (HSF) transcription factors are among the most important transcription factors in plants and are involved in the transcriptional regulation of various stress responses, including drought, salinity, oxidation, osmotic stress, and high light, thereby regulating growth and developmental processes. However, the HFS gene family has not yet been identified in A. mongholicus, and little is known regarding the role of HSF genes in A. mongholicus. This study is based on whole genome analysis of A. mongholicus, identifying a total of 22 AmHSF genes and analyzing their physicochemical properties. Divided into three subgroups based on phylogenetic and gene structural characteristics, including subgroup A (12), subgroup B (9), and subgroup C (1), they are randomly distributed in 8 out of 9 chromosomes of A. mongholicus. In addition, transcriptome data and quantitative real time polymerase chain reaction (qRT-PCR) analyses revealed that AmHSF was differentially transcribed in different tissues, suggesting that AmHSF gene functions may differ. Red and blue light treatment significantly affected the expression of 20 HSF genes in soilless cultivation of A. mongholicus seedlings. AmHSF3, AmHSF3, AmHSF11, AmHSF12, and AmHSF14 were upregulated after red light and blue light treatment, and these genes all had light-corresponding cis-elements, suggesting that AmHSF genes play an important role in the light response of A. mongholicus. Although the responses of soilless-cultivated A. mongholicus seedlings to red and blue light may not represent the mature stage, our results provide fundamental research for future elucidation of the regulatory mechanisms of HSF in the growth and development of A. mongholicus and its response to different light conditions.

Stress biology: Complexity and multifariousness in health and disease.

Preserving and regulating cellular homeostasis in the light of changing environmental conditions or developmental processes is of pivotal importance for single cellular and multicellular organisms alike. To counteract an imbalance in cellular homeostasis transcriptional programs evolved, called the heat shock response, unfolded protein response, and integrated stress response, that act cell-autonomously in most cells but in multicellular organisms are subjected to cell-nonautonomous regulation. These transcriptional programs downregulate the expression of most genes but increase the expression of heat shock genes, including genes encoding molecular chaperones and proteases, proteins involved in the repair of stress-induced damage to macromolecules and cellular structures. Sixty-one years after the discovery of the heat shock response by Ferruccio Ritossa, many aspects of stress biology are still enigmatic. Recent progress in the understanding of stress responses and molecular chaperones was reported at the 12th International Symposium on Heat Shock Proteins in Biology, Medicine and the Environment in the Old Town Alexandria, VA, USA from 28th to 31st of October 2023.

Upregulation of Wheat Heat Shock Transcription Factor TaHsfC3-4 by ABA Contributes to Drought Tolerance.

Drought stress can seriously affect the yield and quality of wheat (Triticum aestivum). So far, although few wheat heat shock transcription factors (Hsfs) have been found to be involved in the stress response, the biological functions of them, especially the members of the HsfC (heat shock transcription factor C) subclass, remain largely unknown. Here, we identified a class C encoding gene, TaHsfC3-4, based on our previous omics data and analyzed its biological function in transgenic plants. TaHsfC3-4 encodes a protein containing 274 amino acids and shows the basic characteristics of the HsfC class. Gene expression profiles revealed that TaHsfC3-4 was constitutively expressed in many tissues of wheat and was induced during seed maturation. TaHsfC3-4 could be upregulated by PEG and abscisic acid (ABA), suggesting that this Hsf may be involved in the regulation pathway depending on ABA in drought resistance. Further results represented that TaHsfC3-4 was localized in the nucleus but had no transcriptional activation activity. Notably, overexpression of TaHsfC3-4 in Arabidopsis thaliana pyr1pyl1pyl2pyl4 (pyr1pyl124) quadruple mutant plants complemented the ABA-hyposensitive phenotypes of the quadruple mutant including cotyledon greening, root elongation, seedling growth, and increased tolerance to drought, indicating positive roles of TaHsfC3-4 in the ABA signaling pathway and drought tolerance. Furthermore, we identified TaHsfA2-11 as a TaHsfC3-4-interacting protein by yeast two-hybrid (Y2H) screening. The experimental data show that TaHsfC3-4 can indeed interact with TaHsfA2-11 in vitro and in vivo. Moreover, transgenic Arabidopsis TaHsfA2-11 overexpression lines exhibited enhanced drought tolerance, too. In summary, our study confirmed the role of TaHsfC3-4 in response to drought stress and provided a target locus for marker-assisted selection breeding to improve drought tolerance in wheat.

Arabidopsis HSFA9 Acts as a Regulator of Heat Response Gene Expression and the Acquisition of Thermotolerance and Seed Longevity.

Heat-shock transcription factors (HSFs) are crucial for regulating plant responses to heat and various stresses, as well as for maintaining normal cellular functions and plant development. HSFA9 and HSFA2 are two of the Arabidopsis class A HSFs and their expressions are dramatically induced in response to heat shock (HS) stress among all 21 Arabidopsis HSFs. However, the detailed biological roles of their cooperation have not been fully characterized. In this study, we employed an integrated approach that combined bioinformatics, molecular genetics and computational analysis to identify and validate the molecular mechanism that controls seed longevity and thermotolerance in Arabidopsis. The acquisition of tolerance to deterioration was accompanied by a significant transcriptional switch that involved the induction of primary metabolism, reactive oxygen species and unfolded protein response, as well as the regulation of genes involved in response to dehydration, heat and hypoxia. In addition, the cis-regulatory motif analysis in normal stored and controlled deterioration treatment (CDT) seeds confirmed the CDT-repressed genes with heat-shock element (HSE) in their promoters. Using a yeast two-hybrid and molecular dynamic interaction assay, it is shown that HSFA9 acted as a potential regulator that can interact with HSFA2. Moreover, the knock-out mutants of both HSFA9 and HSFA2 displayed a significant reduction in seed longevity. These novel findings link HSF transcription factors with seed deterioration tolerance and longevity.

Novel roles of HSFs and HSPs, other than relating to heat stress, in temperature-mediated flowering.

The thermotolerant ability of heat shock factors (HSFs) and heat shock proteins (HSPs) in plants has been shown. Recently, focus has been on their function in plant growth and development under non-stress conditions. Their role in flowering has been suggested given that lower levels of HSF/HSPs resulted in altered flowering in Arabidopsis. Genetic and molecular studies of Arabidopsis HSF/HSP mutants advocated an association with temperature-mediated regulation of flowering, but the fundamental genetic mechanism behind this phenomenon remains obscure. Here we outline plausible integration between HSFs/HSPs and temperature-dependent pathways in plants regulating flowering. Moreover, we discuss how similar pathways can be present in thermoperiodic geophytic plants that require ambient high temperatures for flowering induction.

Physiological and transcriptomic analyses provide insight into thermotolerance in desert plant Zygophyllum xanthoxylum.

BACKGROUND: Heat stress has adverse effects on the growth and reproduction of plants. Zygophyllum xanthoxylum, a typical xerophyte, is a dominant species in the desert where summer temperatures are around 40 °C. However, the mechanism underlying the thermotolerance of Z. xanthoxylum remained unclear. RESULTS: Here, we characterized the acclimation of Z. xanthoxylum to heat using a combination of physiological measurements and transcriptional profiles under treatments at 40 °C and 45 °C, respectively. Strikingly, moderate high temperature (40 °C) led to an increase in photosynthetic capacity and superior plant performance, whereas severe high temperature (45 °C) was accompanied by reduced photosynthetic capacity and inhibited growth. Transcriptome profiling indicated that the differentially expressed genes (DEGs) were related to transcription factor activity, protein folding and photosynthesis under heat conditions. Furthermore, numerous genes encoding heat transcription shock factors (HSFs) and heat shock proteins (HSPs) were significantly up-regulated under heat treatments, which were correlated with thermotolerance of Z. xanthoxylum. Interestingly, the up-regulation of PSI and PSII genes and the down-regulation of chlorophyll catabolism genes likely contribute to improving plant performance of Z. xanthoxylum under moderate high temperature. CONCLUSIONS: We identified key genes associated with of thermotolerance and growth in Z. xanthoxylum, which provide significant insights into the regulatory mechanisms of thermotolerance and growth regulation in Z. xanthoxylum under high temperature conditions.

Role of HSF1 in endogenous protective mechanism underlying mechanical ventilator-induced lung injury in mice: relationship with HMGB1 / 中华麻醉学杂志

Objective:To evaluate the role of heat shock transcription factor 1 (HSF1) in the endogenous protective mechanism underlying mechanical ventilator-induced lung injury (VILI) in mice and the relationship with high mobility group box 1 (HMGB1).Methods:Forty SPF healthy male C57BL/6 mice, aged 6-8 weeks, weighing 20-25 g, were divided into 4 groups ( n=10 each) by the random number table method: control group (group C), VILI group (group VILI), negative control siRNA + VILI group (group NV) and HSF1 siRNA + VILI group (group siRNA). At 48 h before mechanical ventilation, negative control siRNA 5 nmol and HSF1 siRNA 5 nmol were intratracheally injected in NV and siRNA groups respectively, and the solution was diluted to 50 μl with the sterile phosphate buffer in both groups. Group C kept spontaneous breathing for 4 h, and the rest animals were mechanically ventilated (tidal volume 35 ml/kg, respiratory rate 75 breaths/min, inspiratory/expiratory ratio 1∶2, fraction of inspired oxygen 21%) for 4 h. Blood samples from the femoral artery were collected for arterial blood gas analysis immediately after endotracheal intubation and at 4 h of ventilation, and PaO 2 was recorded. Then the mice were sacrificed under deep anesthesia to collect lung tissues and bronchoalveolar lavage fluid (BALF). The concentrations of interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α) and HMGB1 in BALF were determined by enzyme-linked immunosorbent assay. The pathological results were observed by hematoxylin-eosin staining, and lung injury was assessed and scored. The wet/dry (W/D) weight ratio of lung tissues was calculated. The expression of HMGB1 and HSF1 mRNA in lung tissues (by quantitative real-time polymerase chain reaction) and expression of HMGB1 and HSF1 protein in lung tissues (by Western blot) were determined. Results:Compared with group C, PaO 2 was significantly decreased at 4 h of ventilation, the concentrations of TNF-α, IL-1β and HMGB1 in BALF, W/D ratio and lung injury score were increased, and the expression of HMGB1 protein and mRNA in lung tissues was up-regulated in group VILI, group NV and group siRNA ( P<0.05 or 0.01). Compared with group VILI and group NV, PaO 2 was significantly decreased at 4 h of ventilation, the concentrations of TNF-α, IL-1β and HMGB1 in BALF, W/D ratio and lung injury score were increased, and the expression of HMGB1 protein and mRNA in lung tissues was up-regulated, and the expression of HSF1 protein and mRNA was down-regulated in group siRNA ( P<0.05 or 0.01). There was no significant difference in the parameters mentioned above between group VILI and group NV ( P>0.05). Conclusions:HSF1 is involved in the endogenous protective mechanism underlying VILI in mice, which may be related to the down-regulation of HMGB1 expression and attenuation of inflammatory responses in lung tissues.

Response and regulatory mechanisms of heat resistance in pathogenic fungi.

Both the increasing environmental temperature in nature and the defensive body temperature response to pathogenic fungi during mammalian infection cause heat stress during the fungal existence, reproduction, and pathogenic infection. To adapt and respond to the changing environment, fungi initiate a series of actions through a perfect thermal response system, conservative signaling pathways, corresponding transcriptional regulatory system, corresponding physiological and biochemical processes, and phenotypic changes. However, until now, accurate response and regulatory mechanisms have remained a challenge. Additionally, at present, the latest research progress on the heat resistance mechanism of pathogenic fungi has not been summarized. In this review, recent research investigating temperature sensing, transcriptional regulation, and physiological, biochemical, and morphological responses of fungi in response to heat stress is discussed. Moreover, the specificity thermal adaptation mechanism of pathogenic fungi in vivo is highlighted. These data will provide valuable knowledge to further understand the fungal heat adaptation and response mechanism, especially in pathogenic heat-resistant fungi. KEY POINTS: • Mechanisms of fungal perception of heat pressure are reviewed. • The regulatory mechanism of fungal resistance to heat stress is discussed. • The thermal adaptation mechanism of pathogenic fungi in the human body is highlighted.

Heat shock-induced cold acclimation in cucumber through CsHSFA1d-activated JA biosynthesis and signaling.

Cucumber (Cucumis sativus) originated in tropical areas and is very sensitive to low temperatures. Cold acclimation is a universal strategy that improves plant resistance to cold stress. In this study, we report that heat shock induces cold acclimation in cucumber seedlings, via a process involving the heat-shock transcription factor HSFA1d. CsHSFA1d expression was improved by both heat shock and cold treatment. Moreover, CsHSFA1d transcripts accumulated more under cold treatment after a heat-shock pre-treatment than with either heat shock or cold treatment alone. After exposure to cold, cucumber lines overexpressing CsHSFA1d displayed stronger tolerance for cold stress than the wild type, whereas CsHSFA1d knockdown lines obtained by RNA interference were more sensitive to cold stress. Furthermore, both the overexpression of CsHSFA1d and heat-shock pre-treatment increased the endogenous jasmonic acid (JA) content in cucumber seedlings after cold treatment. Exogenous application of JA rescued the cold-sensitive phenotype of CsHSFA1d knockdown lines, underscoring that JA biosynthesis is key for CsHSFA1d-mediated cold tolerance. Higher JA content is likely to lead to the degradation of CsJAZ5, a repressor protein of the JA pathway. We also established that CsJAZ5 interacts with CsICE1. JA-induced degradation of CsJAZ5 would be expected to release CsICE1, which would then activate the ICE-CBF-COR pathway. After cold treatment, the relative expression levels of ICE-CBF-COR signaling pathway genes, such as CsICE1, CsCBF1, CsCBF2 and CsCOR1, in CsHSFA1d overexpression lines were significantly higher than in the wild type and knockdown lines. Taken together, our results help to reveal the mechanism underlying heat shock-induced cold acclimation in cucumber.

The protective effect of nnano-selenium against cadmium-induced cerebellar injury via the heat shock protein pathway in chicken.

Cadmium (Cd) is one of the toxic environmental heavy metals that poses health hazard to animals due to its toxicity. Nano-Selenium (Nano-Se) is a Nano-composite form of Se, which has emerged as a promising therapeutic agent for its protective roles against heavy metals-induced toxicity. Heat shock proteins (HSPs) play a critical role in cellular homeostasis. However, the potential protective effects of Nano-Se against Cd-induced cerebellar toxicity remain to be illustrated. To investigate the toxic effects of Cd on chicken's cerebellum, and the protective effects of Nano-Se against Cd-induced cerebellar toxicity, a total of 80 male chicks were divided into four groups and treated as follows: (A) 0 mg/kg Cd, (B) 1 mg/kg Nano-Se (C) 140 mg/kg Cd + 1 mg/kg Nano-Se (D) 140 mg/kg Cd for 90 days. We tested heat shock protein pathway-related factors including heat shock factors (HSFs) HSF1, HSF2, HSF3 and heat shock proteins (HSPs) HSP10, HSP25, HSP27, HSP40, HSP60, HSP70 and HSP90 expressions. Histopathological results showed that Cd treatment caused degradation of Purkinje cells. In addition, HSFs and HSPs expression decreased significantly in the Cd group. Nano-Se co-treatment with Cd enhanced the expression of HSFs and HSPs. In summary, our findings explicated a potential protective effect of Nano-Se against Cd-induced cerebellar injury in chicken, suggesting that Nano-Se is a promising therapeutic agent for the treatment of Cd toxicity.

Silicon-mediated heat tolerance in higher plants: A mechanistic outlook.

Heat stress, resulting from global warming, is considered one of the major challenges to be addressed for increasing plant survival and productivity worldwide. Although plants have a built-in defense mechanism against heat stress, such strategy seems to be insufficient to counteract heat adversities under extreme temperature regimes. Hence, increasing heat tolerance in plants for sustainable yields is one of the biggest challenges for researchers in the coming decades. Conventional plant breeding approach to enhance heat tolerance has gained some successes; however, more efforts are needed to make plants resilient to heat stress for increasing crop production during ongoing climate change. Thus, exploring 'heat stress mitigation strategies' using cost-effective and eco-friendly approaches may be quick and sustainable alternatives. The use of silicon (Si) and Si-nanoparticles (Si-NPs) in enhancing heat tolerance in plants has recently gained much attention. Application of Si and Si-NPs can assist plants to overcome heat-induced oxidative stress through the acceleration of reactive oxygen species detoxification by modulating the antioxidant systems and regulating transcription of key genes associated with heat stress responses. In fact, molecular rationale behind Si-mediated heat tolerance in plants is largely unknown. In this minireview, we made efforts to understand the mechanistic aspects of heat-induced responses and damages in plants, and possible molecular dynamics of Si-induced heat tolerance in plants. We also highlighted recent advances on how Si induces heat tolerance potential in plants and future perspectives on how Si can contribute to sustainable crop production under the increasing threat of global climate change.

[Heat shock transcription factor family in plants: a review].

With the constant change of global climate, plants are often affected by multiple abiotic stresses such as heat stress, drought stress, cold stress and saline-alkali stress. Heat shock transcription factors (HSFs) are a class of transcription factors widely existing in plants to respond to a variety of abiotic stresses. In this article, we review and summarize the structure, signal regulation mechanism of HSFs and some research in plants like Arabidopsis thaliana, tomato, rice and soybean, to provide reference for further elucidating the role of HSFs in the stress regulation network.

Impact of chronic hyperglycemia on Small Heat Shock Proteins in diabetic rat brain.

Small heat shock proteins (sHsps) are a family of proteins. Some are induced in response to multiple stimuli and others are constitutively expressed. They are involved in fundamental cellular processes, including protein folding, apoptosis, and maintenance of cytoskeletal integrity. Hyperglycemia created during diabetes leads to neuronal derangements in the brain. In this study, we investigated the impact of chronic hyperglycemia on the expression of sHsps and heat shock transcription factors (HSFs), solubility and aggregation of sHsps and amyloidogenic proteins, and their role in neuronal apoptosis in a diabetic rat model. Diabetes was induced in Sprague-Dawley rats with streptozotocin and hyperglycemia was maintained for 16 weeks. Expressions of sHsps and HSFs were analyzed by qRT-PCR and immunoblotting in the cerebral cortex. Solubility of sHsps and amyloidogenic proteins, including α-synuclein and Tau, was analyzed by the detergent soluble assay. Neuronal cell death was analyzed by TUNEL staining and apoptotic markers. The interaction of sHsps with amyloidogenic proteins and Bax was assessed using co-immunoprecipitation. Hyperglycemia decreased Hsp27 and HSF1, and increased αBC, Hsp22, and HSF4 levels at transcript and protein levels. Diabetes induced the aggregation of αBC, Hsp22, α-synuclein, and pTau, as their levels were higher in the insoluble fraction. Additionally, diabetes impaired the interaction of αBC with α-synuclein and pTau. Furthermore, diabetes reduced the interaction of αBC with Bax, which may possibly contribute to neuronal apoptosis. Together, these results indicate that chronic hyperglycemia induces differential responses of sHsps by altering their expression, solubility, interaction, and roles in apoptosis.

Heat shock transcription factor family in plants: a review / 生物工程学报

With the constant change of global climate, plants are often affected by multiple abiotic stresses such as heat stress, drought stress, cold stress and saline-alkali stress. Heat shock transcription factors (HSFs) are a class of transcription factors widely existing in plants to respond to a variety of abiotic stresses. In this article, we review and summarize the structure, signal regulation mechanism of HSFs and some research in plants like Arabidopsis thaliana, tomato, rice and soybean, to provide reference for further elucidating the role of HSFs in the stress regulation network.

Functional characterization of maize heat shock transcription factor gene ZmHsf01 in thermotolerance.

BACKGROUND: Heat waves can critically influence maize crop yields. Plant heat shock transcription factors (HSFs) play a key regulating role in the heat shock (HS) signal transduction pathway. METHOD: In this study, a homologous cloning method was used to clone HSF gene ZmHsf01 (accession number: MK888854) from young maize leaves. The transcript levels of ZmHsf01 were detected using qRT-PCR in different tissues and treated by HS, abscisic acid (ABA), hydrogen peroxide (H2O2), respectively, and the functions of gene ZmHsf01 were studied in transgenic yeast and Arabidopsis. RESULT: ZmHsf01 had a coding sequence (CDS) of 1176 bp and encoded a protein consisting of 391 amino acids. The homologous analysis results showed that ZmHsf01 and SbHsfA2d had the highest protein sequence identities. Subcellular localization experiments confirmed that ZmHsf01 was localized in the nucleus. ZmHsf01 was expressed in many maize tissues. It was up-regulated by HS, and up-regulated in roots and down-regulated in leaves under ABA and H2O2treatments. ZmHsf01-overexpressing yeast cells showed increased thermotolerance. In Arabidopsis seedlings, ZmHsf01 compensated for the thermotolerance defects of mutant athsfa2, and ZmHsf01-overexpressing lines showed enhanced basal and acquired thermotolerance. When compared to wild type (WT) seedlings, ZmHsf01-overexpressing lines showed higher chlorophyll content and survival rates after HS. Heat shock protein (HSP) gene expression levels were more up-regulated in ZmHsf01-overexpressing Arabidopsis seedlings than WT seedlings. These results suggest that ZmHsf01 plays a vital role in response to HS in plant.

The "HSF connection": Pleiotropic regulation and activities of Heat Shock Factors shape pathophysiological brain development.

The Heat Shock Factors (HSFs) have been historically identified as a family of transcription factors that are activated and work in a stress-responsive manner, after exposure to a large variety of stimuli. However, they are also critical in normal conditions, in a life long manner, in a number of physiological processes that encompass gametogenesis, embryonic development and the integrity of adult organs and organisms. The importance of such roles is emphasized by the devastating impact of their deregulation on health, ranging from reproductive failure, neurodevelopmental disorders, cancer, and aging pathologies, including neurodegenerative disorders. Here, we provide an overview of the delicate choreography of the regulation of HSFs during neurodevelopment, at prenatal and postnatal stages. The regulation of HSFs acts at multiple layers and steps, and comprises the control of (i) HSF mRNA and protein levels, (ii) HSF activity in terms of DNA-binding and transcription, (iii) HSF homo- and hetero-oligomerization capacities, and (iv) HSF combinatory set of post-translational modifications. We also describe how these regulatory mechanisms operate in the normal developing brain and how their perturbation impact neurodevelopment under prenatal or perinatal stress conditions. In addition, we put into perspective the possible role of HSFs in the evolution of the vertebrate brains and the importance of the HSF pathway in a large variety of neurodevelopmental disorders.

Molecular characterization and protein structure prediction of heat shock transcriptional factors in goat (Capra hircus) and sheep (Ovis aries).

The heat shock factors are important as they are master regulator of heat shock response. There are only few mammalian HSFs which have been characterized, namely HSF-1, HSF-2, HSF-4 and HSF-5. The present study was aimed to clone and sequence characterize the partial open reading frames (ORFs) of HSF-2 and HSF-5 gene from cDNA isolated from testicular tissue of sheep (Macheri) and goat (Beetal). The partial ORFs of HSF-2 gene was observed to be 1627 bp in sheep and 1179 bp in goat and for HSF-5 it is 1137 bp in sheep and 1027 bp in goat. HSF-2 and HSF-5 encode a putative protein of 593 and 461 amino acid in goat and 568 and 553 amino acid in sheep, respectively. Phylogenetic analysis between the different orthologs suggested that these proteins are conserved from bovine to humans as well as in other mammals. Further, domain analyses using PredictNLS, MARCOIL and NetNES revealed that the members of HSF-2 protein orthologs contained all major domains, i.e., DNA-binding domain (DBD) and oligomerization domain (HR-A/B, and HR-C). The 3D structure of sheep and goat HSF-2 protein was predicted using SWISS-MODEL, which showed similar confirmation with the human HSF-2 protein sequence showing functional similarity between them.

Integration of Transcriptomics and Metabolomics for Pepper (Capsicum annuum L.) in Response to Heat Stress.

Heat stress (HS), caused by extremely high temperatures, is one of the most severe forms of abiotic stress in pepper. In the present study, we studied the transcriptome and metabolome of a heat-tolerant cultivar (17CL30) and a heat-sensitive cultivar (05S180) under HS. Briefly, we identified 5754 and 5756 differentially expressed genes (DEGs) in 17CL30 and 05S180, respectively. Moreover, we also identified 94 and 108 differentially accumulated metabolites (DAMs) in 17CL30 and 05S180, respectively. Interestingly, there were many common HS-responsive genes (approximately 30%) in both pepper cultivars, despite the expression patterns of these HS-responsive genes being different in both cultivars. Notably, the expression changes of the most common HS-responsive genes were typically much more significant in 17CL30, which might explain why 17CL30 was more heat tolerant. Similar results were also obtained from metabolome data, especially amino acids, organic acids, flavonoids, and sugars. The changes in numerous genes and metabolites emphasized the complex response mechanisms involved in HS in pepper. Collectively, our study suggested that the glutathione metabolic pathway played a critical role in pepper response to HS and the higher accumulation ability of related genes and metabolites might be one of the primary reasons contributing to the heat resistance.

Genome-wide characterization and evolutionary analysis of heat shock transcription factors (HSFs) to reveal their potential role under abiotic stresses in radish (Raphanus sativus L.).

BACKGROUND: Abiotic stresses due to climate change pose a great threat to crop production. Heat shock transcription factors (HSFs) are vital regulators that play key roles in protecting plants against various abiotic stresses. Therefore, the identification and characterization of HSFs is imperative to dissect the mechanism responsible for plant stress responses. Although the HSF gene family has been extensively studied in several plant species, its characterization, evolutionary history and expression patterns in the radish (Raphanus sativus L.) remain limited. RESULTS: In this study, 33 RsHSF genes were obtained from the radish genome, which were classified into three main groups based on HSF protein domain structure. Chromosomal localization analysis revealed that 28 of 33 RsHSF genes were located on nine chromosomes, and 10 duplicated RsHSF genes were grouped into eight gene pairs by whole genome duplication (WGD). Moreover, there were 23 or 9 pairs of orthologous HSFs were identified between radish and Arabidopsis or rice, respectively. Comparative analysis revealed a close relationship among radish, Chinese cabbage and Arabidopsis. RNA-seq data showed that eight RsHSF genes including RsHSF-03, were highly expressed in the leaf, root, cortex, cambium and xylem, indicating that these genes might be involved in plant growth and development. Further, quantitative real-time polymerase chain reaction (RT-qPCR) indicated that the expression patterns of 12 RsHSF genes varied upon exposure to different abiotic stresses including heat, salt, and heavy metals. These results indicated that the RsHSFs may be involved in abiotic stress response. CONCLUSIONS: These results could provide fundamental insights into the characteristics and evolution of the HSF family and facilitate further dissection of the molecular mechanism responsible for radish abiotic stress responses.