Stress Adaptation Mechanisms Research Articles

Genome-Wide Identification and Characterization of the BZR Transcription Factor Gene Family in Leymus chinensis

Background/Objectives: The BZR gene family, a critical transcription factor in the brassinosteroid (BR) signaling pathway, regulates plant growth and development. Despite its significance, the BZR gene family in Leymus chinensis, a valuable forage grass renowned for its stress tolerance and nutritional quality, remains uncharacterized, and its functional roles are largely unexplored. Methods: Employing advanced bioinformatics tools, we conducted a genome-wide survey to identify members of the BZR gene family in L. chinensis. Phylogenetic analyses were performed to classify these genes into distinct clades, while gene structure and conserved motif analyses assessed their evolutionary conservation and potential regulatory mechanisms. Additionally, transcriptome sequencing was utilized to examine the expression patterns of BZR genes in response to simulated animal grazing. Results: Eight LcBZR genes were identified, evenly distributed across all seven chromosomes. Phylogenetic analysis categorized these genes into three distinct groups, reflecting their evolutionary relationships. Most LcBZR genes exhibited highly conserved gene structures and motifs, with promoters enriched in cis-acting elements such as G-box and ARE. Expression profiling revealed that LcBZR genes are predominantly expressed in key tissues, particularly leaves and roots, suggesting their involvement in critical physiological processes. Transcriptomic analysis demonstrated that simulated animal grazing modulated the expression levels of LcBZR genes, implicating their role in promoting cellular elongation and division through the BR signaling pathway. Conclusions: This study highlights the crucial role of LcBZR genes in regulating plant growth, development, and response to environmental stimuli, providing a foundational basis for understanding the molecular mechanisms of BR-mediated plant development and stress adaptation.

Insights into the Photosynthetic Efficiency and Chloroplast Ultrastructure of Heat-Stressed Edamame Cultivars During the Reproductive Stages

High temperatures have adverse impacts on the photosynthetic efficiency and yield of many crop plants. This study investigated how high temperatures affect the photosynthetic efficiency parameters and chloroplast ultrastructure of three edamame cultivars (AGS354, UVE17, and UVE14) at the reproductive stages (flowering and pod-filling). Heat stress (HS) treatments were performed under controlled conditions in climate chambers set at 25/18 °C (control), 30/23 °C (HS-I), and 35/28 °C (HS-II). The AGS354 cultivar exhibited the greatest susceptibility under HS-II treatment, characterised by a reduction in the photochemical reactions, decreased chlorophyll-a (chl-a) and carotenoid accumulation, the highest increase in the starch grain traits, and reduced plastoglobule and grana area traits. In UVE 14 and UVE17, the HS-II treatment enhanced chl-a and chl-b accumulation. Elevated carotenoid levels in UVE14 and UVE17 likely protected chlorophyll from degradation and mitigated photooxidative damage. The HS-II treatment also enhanced the grana traits, supporting improved light-harvesting capacity during heat stress in UVE14 and 17. However, heat stress disrupted the photochemical reactions (quantum efficiency of photosystem II, performance index absorbance, and performance index), indicating that elevated carotenoids alone do not exhibit complete tolerance to heat stress. Since plastoglobules play an essential in carotenoid biosynthesis, increased or stabilised plastoglobule traits in UVE14 and UVE17 under HS-II treatment strongly indicate improved heat stress tolerance. Overall, UVE14 and UVE17 emerged as the most heat-tolerant cultivars, with AGS354 being the most susceptible. These findings provide valuable insights into heat stress adaptation mechanisms and suggest the UVE14 and UVE17 cultivars as potential candidates for breeding heat-tolerant edamame cultivars.

Emerging Trends in Secondary Metabolite Research in Caryophyllales: Betalains and Their Roles in Plant Adaptation and Defense Mechanisms.

Betalains, a distinctive group of nitrogen-containing pigments exclusive to the Caryophyllales order, possess diverse biological activities such as antioxidant, anti-inflammatory, and antimicrobial properties, making them highly valuable for applications in food, nutraceutical, and pharmaceutical industries. This Review provides a comprehensive analysis of betalain biosynthesis, structural diversity, and ecological significance, highlighting their roles in enhancing stress resilience, adaptation mechanisms, and plant evolutionary strategies. The evolutionary development of betalains is explored, revealing their emergence through gene duplication events and providing insights into their mutual exclusivity with anthocyanins. This study utilizes comparative genetics and advanced molecular tools to uncover the intricate regulatory networks involving transcription factors such as MYB, bHLH, WRKY, and SPL, which govern betalain biosynthesis. Furthermore, the Review discusses innovative transgenic studies that introduce betalains into non-native species, demonstrating their potential to enhance stress tolerance and boost agricultural productivity. While significant progress has been made in understanding betalain biosynthesis pathways, the evolutionary relationships with anthocyanins and the specific ecological functions of betalains in plants remain areas of ongoing exploration. Future research directions include integrating chemotaxonomic studies, molecular phylogenetics, and multiomics approaches to unravel the full spectrum of betalain functions and regulatory mechanisms. Such studies are essential to deepening our understanding of these vibrant pigments and their evolutionary implications, offering new opportunities for biotechnological innovations and sustainable agricultural practices. This Review stands out by combining genetic, ecological, and evolutionary perspectives, providing novel insights into the multifunctionality of betalains and their potential to drive future advancements in plant science and biotechnology.

Comprehensive review of plant small signaling peptides: From stress adaptation mechanisms to practical solutions for crop resilience.

Small signaling peptides (SSPs), short proteins of fewer than 100 amino acids, serve as pivotal signaling molecules with diverse structural features, post-translational modifications, and functional roles. They regulate various aspects of plant growth and development by modulating specific cellular signaling pathways. Research has shown that many SSPs are essential for mediating responses to environmental stresses. This review presents the structure, characteristics, and classification of plant SSPs and elucidates their roles in resistance signaling pathways through interactions with their specific receptors. We then summarize recent findings on the biological functions and regulatory mechanisms of SSPs in response to both biotic and abiotic stresses. Finally, we discuss the potential applications and future prospects of these peptides in plant protection. This review offers valuable insights for enhancing plant resilience to environmental stress and advancing sustainable agricultural practices, while also providing key references and perspectives to accelerate research on SSPs in plants.

Comprehensive Analysis of the NHX Gene Family and Its Regulation Under Salt and Drought Stress in Quinoa (Chenopodium quinoa Willd.).

Background/Objectives: Abiotic stresses such as salinity and drought significantly constrain crop cultivation and affect productivity. Quinoa (Chenopodium quinoa Willd.), a facultative halophyte, exhibits remarkable tolerance to drought and salinity stresses, making it a valued model for understanding stress adaptation mechanisms. The objective of this study was to identify and characterize Sodium/Hydrogen antiporter (NHX) genes from the quinoa genome and study their role in stress tolerance. Methods: We identified and characterized 10 NHX genes from the quinoa genome, which belong to the monovalent cation/proton antiporter 1 (CPA1) superfamily. Comprehensive analysis, including phylogenetic relationships, motif patterns, and structural characteristics, was performed to classify these genes into three subfamilies. Physicochemical properties such as isoelectric point (pI), GRAVY, and transmembrane domains were examined. Promoter analysis was conducted to identify cis-elements linked to abiotic stress responses, phytohormone signalling, and light regulation. qPCR analysis was used to assess the differential expression patterns of CqNHX genes under salt and drought stress. Results: The analysis revealed that the NHX genes were divided into three subfamilies localized to vacuolar, plasma, and endosomal membranes. These genes exhibited structural and functional diversity. Promoter analysis indicated the presence of cis-elements associated with abiotic stress responses, phytohormone signalling, and light regulation, suggesting diverse regulatory roles. qPCR analysis revealed differential expression patterns of CqNHX genes under salt and drought stress, with vacuolar NHXs showing higher induction in leaf tissues under salinity. This underscores their critical role in sodium sequestration and ion homeostasis. Evolutionary analysis indicated a high degree of conservation within subfamilies, alongside evidence of purifying selection. Conclusions: The findings enhance our understanding of the molecular basis of stress tolerance in quinoa and provide valuable targets for genetic engineering to improve crop resilience to environmental challenges.

Morphological, Physiological, and Molecular Responses to Heat Stress in Brassicaceae.

Food security is threatened by global warming, which also affects agricultural output. Various components of cells perceive elevated temperatures. Different signaling pathways in plants distinguish between the two types of temperature increases, mild warm temperatures and extremely hot temperatures. Given the rising global temperatures, heat stress has become a major abiotic challenge, affecting the growth and development of various crops and significantly reducing productivity. Brassica napus, the second-largest source of vegetable oil worldwide, faces drastic reductions in seed yield and quality under heat stress. This review summarizes recent research on the genetic and physiological impact of heat stress in the Brassicaceae family, as well as in model plants Arabidopsis and rice. Several studies show that extreme temperature fluctuations during crucial growth stages negatively affect plants, leading to impaired growth and reduced seed production. The review discusses the mechanisms of heat stress adaptation and the key regulatory genes involved. It also explores the emerging understanding of epigenetic modifications during heat stress. While such studies are limited in B. napus, contrasting trends in gene expression have been observed across different species and cultivars, suggesting these genes play a complex role in heat stress tolerance. Key knowledge gaps are identified regarding the impact of heat stress during the growth stages of B. napus. In-depth studies of these stages are still needed. The profound understanding of heat stress response mechanisms in tissue-specific models are crucial in advancing our knowledge of thermo-tolerance regulation in B. napus and supporting future breeding efforts for heat-tolerant crops.

AozC, a zn(II)2Cys6 transcription factor, negatively regulates salt tolerance in Aspergillus oryzae by controlling fatty acid biosynthesis

BackgroundIn the soy sauce fermentation industry, Aspergillus oryzae (A. oryzae) plays an essential role and is frequently subjected to high salinity levels, which pose a significant osmotic stress. This environmental challenge necessitates the activation of stress response mechanisms within the fungus. The Zn(II)2Cys6 family of transcription factors, known for their zinc binuclear cluster-containing proteins, are key regulators in fungi, modulating various cellular functions such as stress adaptation and metabolic pathways.ResultsOverexpression of AozC decreased growth rates in the presence of salt, while its knockdown enhanced growth, the number of spores, and biomass, particularly under conditions of 15% salt concentration, doubling these metrics compared to the wild type. Conversely, the knockdown of AozC via RNA interference significantly enhanced spore density and dry biomass, particularly under 15% salt stress, where these parameters were markedly improved over the wild type strain. Moreover, the overexpression of AozC led to a downregulation of the FAD2 gene, a pivotal enzyme in the biosynthesis of unsaturated fatty acids (UFAs), which are essential for preserving cell membrane fluidity and integrity under saline conditions. Transcriptome profiling further exposed the influence of AozC on the regulation of UFA biosynthesis and the modulation of critical stress response pathways. Notably, the regulatory role of AozC in the mitogen-activated protein kinase (MAPK) signaling and ABC transporters pathways was highlighted, underscoring its significance in cellular osmotic balance and endoplasmic reticulum homeostasis. These findings collectively indicate that AozC functions as a negative regulator of salt tolerance in A. oryzae.ConclusionThis research suggest that AozC acts as a negative regulator in salt tolerance and modulates fatty acid biosynthesis in response to osmotic stress. These results provide insights into the regulatory mechanisms of stress adaptation in A. oryzae.

Stress signaling, response, and adaptive mechanisms in submerged macrophytes under PFASs and warming exposure.

Heat stress disturbs cellular homeostasis and alters the fitness of individual organisms. However, it is unclear whether thermal perturbations exacerbate the toxic effects of per- and polyfluorinated alkyl substances (PFASs) on trophic endpoints in freshwater ecosystems. We conducted a mesocosm experiment to investigate the impact of warming and PFASs on the widespread submerged macrophytes (Hydrilla verticillata) at a molecular level. Quantitative and air flow-assisted ionization mass spectrometry imaging results showed that warming significantly increased the accumulation of PFOS (3.53L/kg) in the submerged leaf tissues. Accumulation of PFASs altered H. verticillata intracellular scavenging enzymes, an effect that may be exacerbated by 4°C warming. Warming and PFASs influenced photosynthesis, biological rhythms, and ecological stoichiometry, causing a decrease in metabolites linked to the tricarboxylic acid cycle and amino acid metabolism, which compromised nitrogen use efficiency (9.9%-30.4% reduction in nitrogen content, 0.8%-22.8% increase in C:N ratios). Additionally, metabolites are linked to the antioxidant system or cell wall components, with linoleic acid decreasing by 17.1%-82.8% and carbohydrate-related compounds dropping by 52.2%-89.0%. Our modeling analyses revealed that H. verticillata enriched with PFASs could pose secondary risks when consumed by herbivorous fish (Ctenopharyngodon idellus) under warming, potentially affecting food chain dynamics.

Comparative metabolic study of planktonic and sessile cells in Salmonella Enteritidis ATCC 13076: Elucidating metabolic pathways driving biofilm formation.

Microorganisms tend to accumulate on surfaces, forming aggregates such as biofilms, which grant them resistance to various environmental stressors and antimicrobial agents. This ability has hindered the effective treatment of diseases caused by pathogenic microorganisms, including Salmonella, which is responsible for a significant number of deaths worldwide. This study aimed to compare the metabolic profiles of planktonic and sessile cells of Salmonella Enteritidis using a metabolomics approach. The metabolites extracted from the bacterial cells were analyzed by LC/MS approach. Raw data were analyzed using Thermo Xcalibur v 3.1 software. For data processing, XCMS was used for feature detection, retention time, correction and alignment. The data matrix was analyzed by uni- and multivariate statistical methods (PCA, PLS-DA, Heatmap) in MetaboAnalyst software v 6.0. A total of 121 metabolites were presumptively identified as differential metabolic characteristics between the two bacterial states, and they were associated with their corresponding metabolic pathways. Among the metabolites that exhibited positive modulation in planktonic cells were proline, phenylalanine, which act as precursors of essential metabolites and part of the stress adaptation mechanisms. In addition, putrescine and cadaverine, play crucial roles in growth, stress response, and cell stability In contrast, the most representative metabolites in sessile cells included lysine, adenosine, purines, pyrimidines, and citrate, mainly associated with maintaining cellular homeostasis, stress response and metabolic regulation. Finally, pathway enrichment analysis identified metabolic changes in 11 pathways, predominantly involving purine and pyrimidine metabolism, arginine and proline metabolism, and vitamin B6 metabolism. These findings facilitated the identification of potential metabolic pathways associated with biofilm formation in the sessile cells of Salmonella Enteritidis.

Changes in Growth and Metabolic Profile of Scutellaria baicalensis Georgi in Response to Sodium Chloride.

Scutellaria baicalensis Georgi is a valuable medicinal plant of the Lamiaceae family. Its roots have been used in Traditional Chinese Medicine (under the name Huang-qin) since antiquity and are nowadays included in Chinese and European Pharmacopoeias. It is abundant in bioactive compounds which constitute up to 20% of dried root mass. These substances are lipophilic flavones with unsubstituted B-ring, baicalein, and wogonin and their respective glucuronides-baicalin and wogonoside being the most abundant. The content of these compounds is variable and the environmental factors causing this remain partially unknown. The role of these compounds in stress response is still being investigated and in our efforts to measure the effect of NaCl treatment on S. baicalensis growth and metabolic profile, we hope to contribute to this research. Short-term exposure to salt stress (50, 100, and 150 mM NaCl) resulted in a marked increase of baicalein from 1.55 mg to 2.55 mg/g DM (1.6-fold), baicalin from 8.2 mg to 14.7 mg (1.8-fold), wogonin from 4.9 to 6.8 (1.4-fold), and wogonoside from 3.3 to 6.8 mg/g DM (2-fold) in the roots. Conversely, in the aerial parts, the content of individual major flavonoids: carthamidine-7-O-glucuronide and scutellarein-7-O-glucuronide decreased the most by 10-50% from 18.6 mg to 11.3 mg/g (1.6-fold less) and from 6.5 mg to 3.4 mg/g DM (0.52-fold less), respectively. The amino acid profile was also altered with an increase in root concentrations of the following amino acids: arginine from 0.19 to 0.33 mg/g (1.7-fold), glutamate from 0.09 to 0.16 mg/g DM (1.6-fold), alanine from 0.009 to 0.06 mg/g (6.8-fold), proline from 0.011 to 0.029 (2.4-fold) and lysine from 0.016 to 0.063 mg/g (3.9-fold). Aspartate concentration decreased from 0.01 to 0.002 mg/g (4.8-fold less) at 150 mM NaCl. In the aerial parts, the concentration and variation in levels of specific amino acids differed among groups. For instance, the glutamate content exhibited a significant increase exclusively in the treatment group, rising from 0.031 to 0.034 mg/g, representing a 1.2-fold increase. Proline concentration showed a marked increase across all treated groups with the highest from 0.011 to 0.11 mg/g (10-fold). In conclusion, moderate salt stress was shown to increase S. baicalensis root biomass and flavonoid content which is rarely observed in a glycophyte species and provides a foundation for further studies on the mechanisms of osmotic stress adaptation on the specialized metabolism level.

Dynamic Dysregulation of Ribosomal Protein Genes in Mouse Brain Stress Models

Emphasizing their evolutionarily conserved role in stress adaptation mechanisms, ribosomal protein genes (RPGs) are observed to be downregulated in various stressors and across phyla. However, this evolutionarily conserved stress response is not well explored in mouse models of neurobiological stress. This study investigates the dysregulation patterns of RPGs in various murine preclinical stress paradigms across different brain regions using available transcriptomic data and identifies the non-canonical ribosomal functions using synaptic gene-ontology terms. Without a discernible structure across different brain areas, we observed heterogeneous dysregulation, encompassing either up or downregulation in both cytoplasmic and mitochondrial RPGs. However, downregulation was more prominent than upregulation, and the overall dysregulation seems more prevalent in the chronic stress paradigm compared to stress paradigms involving acute and early-life stress. Enrichment analysis significantly associates dysregulated RPGs with post-synaptic gene ontology terms, emphasizing their involvement in synaptic modulation. Overall, the study demonstrates ribosomal dysregulation as an evolutionarily conserved stress response mechanism during different mouse stress paradigms. We discuss the possibility that the variability in the directionality of dysregulation may emerge as a potential marker of neuronal activity in response to diverse stress paradigms and the involvement of paradigm-specific RPG dysregulation either in the process of global downscaling of ribosome biogenesis or in the process of ribosomal heterogeneity, each leading to a different effect.

Physiological and Transcriptomic Dynamics in Mulberry: Insights into Species-Specific Responses to Midday Depression.

Background/Objective: The midday depression of photosynthesis, a physiological phenomenon driven by environmental stress, impacts plant productivity. This study aims to elucidate the molecular and physiological responses underlying midday depression in two mulberry species, Ewu No. 1 (Ew1) and Husan No. 32 (H32), to better understand their species-specific stress adaptation mechanisms. Methods: RNA-seq analysis was conducted on leaf samples collected at three time points (10:00 a.m., 12:00 p.m., and 4:00 p.m.), identifying 22,630 differentially expressed genes (DEGs). A comparative Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was performed to reveal the involvement of key metabolic and signaling pathways in stress responses. Results: Ew1 displayed enhanced stress tolerance by upregulating genes involved in energy management, water conservation, and photosynthetic processes, maintaining higher photosynthetic rates under midday stress. In contrast, H32 adopted a more conservative response, downregulating genes related to photosynthesis and metabolism, favoring survival at the expense of productivity. The KEGG analysis highlighted starch and sucrose metabolism and plant hormone signaling as critical pathways contributing to these species-specific responses. Conclusions: Ew1's adaptive molecular strategies make it more suitable for environments with variable light and temperature conditions, while H32's conservative approach may limit its productivity. These findings provide valuable insights for breeding programs aimed at improving stress tolerance and photosynthetic efficiency in mulberry and other crops, particularly under fluctuating environmental conditions.

Nrf2-Dependent Adaptation to Oxidative Stress Protects Against Progression of Diabetic Nephropathy.

Aims: Adaptation to oxidative stress is essential for maintaining protein and redox homeostasis in mammalian cells. Palmitic acid (PA) plays a central role in oxidative stress and immunoproteasome regulation in podocytes and diabetes, and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have beneficial impact on diabetes. The role of Nrf2 in adaptation to oxidative stress and regulation of immunoproteasome by PA and EPA/DHA in podocytes and diabetic kidneys is not well defined. The present study describes the effect of PA- and EPA/DHA-induced oxidative stress in regulating Nrf2/immuoproteasome pathway in a model system relevant to diabetic nephropathy (DN). Results: Short PA exposure to podocytes promotes the upregulation of antioxidant proteins and immunoproteasome mediated by Nrf2, leading to acute transient oxidative stress adaptation. Both short- and long-term incubation of EPA or DHA in podocytes induced oxidative stress and activation of Nrf2, causing persistent oxidative stress adaptation. Long PA exposure to podocytes decreased the Nrf2 activity, and EPA/DHA attenuated these effects of PA. In db/db mice, feeding of EPA/DHA-rich fish oil increased oxidative stress in kidneys and induced renal cortical Nrf2 nuclear translocation and immunoproteasome overexpression, inhibiting the progression of DN. Innovation and Conclusion: We demonstrate an oxidative stress adaptation mechanism by PA and EPA/DHA regulated by Nrf2 in podocytes and kidneys of type 2 diabetes. This work provides an important insight into the pathogenetic mechanisms of DN by PA-induced oxidative stress. We conclude that activation of Nrf2-immunoproteasome signaling pathway by EPA/DHA plays a crucial role in abrogating the proteotoxic stress in DN. Antioxid. Redox Signal. 00, 000-000.

Genome-wide identification of the Phospholipase D (PLD) gene family in Chinese white pear (Pyrus bretschneideri) and the role of PbrPLD2 in drought resistance

The Chinese white pear (Pyrus bretschneideri), a vital fruit crop, is highly susceptible to abiotic stresses, especially drought, which poses a major threat to its growth and productivity. Phospholipase D (PLD) genes are pivotal in orchestrating plant responses to abiotic stresses, acting as key regulators in stress adaptation mechanisms. This study systematically identified and functionally characterized the entire PLD gene family in P. bretschneideri through a comprehensive genome-wide analysis. A total of 20 PbrPLD genes were identified, and they were categorized into five subfamilies based on phylogenetic analysis. chromosome localization, gene structure, and conserved motif analyses revealed that these genes have diverse evolutionary histories. Cis-acting element analysis and expression profiling under drought stress indicated that several PbrPLD genes, particularly PbrPLD2, are strongly induced by drought. Overexpression of PbrPLD2 in both Arabidopsis thaliana and pear demonstrated enhanced drought tolerance through improved stomatal closure and increased expression of drought-responsive genes. These findings highlight the critical role of PbrPLD2 in drought resistance and provide a theoretical and experimental foundation for molecular breeding in pear and other fruit crops.

Genome-wide analysis of the potato GRF gene family and their expression profiles in response to hormone and Ralstonia solanacearum infection.

Potato (Solanum tuberosum L.) is one of the most economically significant crops globally. Nevertheless, potato cultivation is becoming increasingly susceptible to a multitude of diseases, including bacterial wilt, which is caused by Ralstonia solanacearum. To identify the GRF gene family in potatoes and to examine their expression profiles in response to hormones and R. solanacearum infection. A comprehensive genome-wide analysis was conducted to identify the GRF gene family in the potato genome. A total of 13 GRF genes were identified from the latest potato genome, including five StGRFs belonging to the ɛ group and eight of the non-ɛ group. The transcriptional responses of the StGRFs to two biotic stress-related phytohormones (SA and MeJA) were defined, as well as the response to infection with R. solanacearum in a bacterial wilt-sensitive cultivar, S. tuberosum 'Qingshu 9'. Many StGRF genes exhibited high induction levels in response to R. solanacearum infection and SA treatment while displaying a marked decline in expression in the presence of MeJA. Furthermore, protein interaction network analysis revealed that the StGRF proteins interact with several candidate target proteins, indicating that GRF proteins are ubiquitous regulators in potatoes. However, the associations between two type III effectors (T3Es) RipAC/RipH2 from R. solanacearum isolates and StGRF7 were not detectable in a yeast two-hybrid assay. This study provides comprehensive information on the GRF gene family and lays a foundation for further research on the molecular mechanism of potato biotic stress adaptation.

Challenges of Salinity Intrusion and Drought Stress on Olive Tree Cultivation on Mljet Island.

Understanding genotype-specific responses to environmental stressors is vital for developing resilience strategies that ensure sustainable olive cultivation and productivity. In this work, cultivar 'Oblica' and several olive genotypes from the island of Mljet (Croatia) were exposed to short-term (21 days) salinity and drought treatments. In contrast to other olive genotypes, genotype M29 as well as cultivar 'Oblica' managed to maintain growth and chlorophyll a levels under salinity stress to the same level as the control. Drought, however, significantly reduced the growth parameters in all olive trees. Cultivar 'Oblica' accumulated the greatest amount of Na+ ions in the leaves compared to olive genotypes from the island of Mljet, demonstrating superior resistance by translocating Na+ to leaf vacuoles. The observed reduction in K+ content in the roots of olive trees under all treatments suggests a generalized stress response. On the other hand, effective Ca2+ uptake has been identified as a crucial energy-saving strategy that olive trees use to cope with brief periods of salinity and drought. The proline content and activities of superoxide dismutase (SOD) and guaiacol peroxidase (GPOX) varied among the olive trees, highlighting the importance of antioxidative capacities and stress adaptation mechanisms. According to the obtained results, stress-resistant olive genotypes like 'Oblica' and M29 show potential for breeding resilient varieties.

Genome-Wide Identification, Evolution, and Expression Analysis of the Dirigent Gene Family in Cassava (Manihot esculenta Crantz)

Dirigent (DIR) genes play a pivotal role in plant development and stress adaptation. Manihot esculenta Crantz, commonly known as cassava, is a drought-resistant plant thriving in tropical and subtropical areas. It is extensively utilized for starch production, bioethanol, and animal feed. However, a comprehensive analysis of the DIR family genes remains unexplored in cassava, a crucial cash and forage crop in tropical and subtropical regions. In this study, we characterize a total of 26 cassava DIRs (MeDIRs) within the cassava genome, revealing their uneven distribution across 13 of the 18 chromosomes. Phylogenetic analysis classified these genes into four subfamilies: DIR-a, DIR-b/d, DIR-c, and DIR-e. Comparative synteny analysis with cassava and seven other plant species (Arabidopsis (Arabidopsis thaliana), poplar (Populus trichocarpa), soybean (Glycine max), tomato (Solanum lycopersicum), rice (Oryza sativa), maize (Zea mays), and wheat (Triticum aestivum)) provided insights into their likely evolution. We also predict protein interaction networks and identify cis-acting elements, elucidating the functional differences in MeDIR genes. Notably, MeDIR genes exhibited specific expression patterns across different tissues and in response to various abiotic and biotic stressors, such as pathogenic bacteria, cadmium chloride (CdCl2), and atrazine. Further validation through quantitative real-time PCR (qRT-PCR) confirmed the response of DIR genes to osmotic and salt stress. These findings offer a comprehensive resource for understanding the characteristics and biological functions of MeDIR genes in cassava, enhancing our knowledge of plant stress adaptation mechanisms.

A systematic analysis of GASA family members in the Salix matsudana genome: Characterization, expression profile, and putative function in antioxidation

The gibberellic acid stimulated Arabidopsis (GASA) gene family, specific to plants, plays a pivotal role in growth, development, and response to diverse environmental stresses. Despite their importance, GASA genes in willow trees have been little studied. Here, 35 SmGASAs were identified from the Salix matsudana genome, which exhibited similar physical and chemical proprieties to GASAs in other species. A phylogenetic analysis revealed that GASAs from Populus trichocarpa, Vitis vinifera, Nicotiana tabacum, Oryza sativa, Arabidopsis thaliana, and S. matsudana are categorized into three distinct subfamilies. It appeared that polyploidization and segmental duplication have contributed to the expansion and diversification of the SmGASA family. These genes were significantly enriched in response to GA and oxygen-containing compounds. The diverse expression patterns observed across willow varieties suggested functional variation of SmGASAs throughout their evolutionary history. The expression profiles of SmGASAs were further analyzed in response to different treatments (i.e., salt, submergence, and polyethylene glycol (PEG)), indicating a potential role for SmGASAs in adapting to these stressors in willows. Remarkably, SmGASAs were shown to detoxify hydrogen peroxide (H2O2), highlighting their potent antioxidant properties. Overall, the comprehensive genomic analysis of willow SmGASAs shed light on their role in stress responses, offering valuable insights for future research and supporting the hypothesis of their involvement in stress adaptation mechanisms.

M6A demethylation of FOSL1 mRNA protects hepatoma cells against necrosis under glucose deprivation.

Stress-adaptive mechanisms enabling cancer cells to survive under glucose deprivation remain elusive. N6-methyladenosine (m6A) modification plays important roles in determining cancer cell fate and cellular stress response to nutrient deficiency. However, whether m6A modification functions in the regulation of cancer cell survival under glucose deprivation is unknown. Here, we found that glucose deprivation reduced m6A modification levels. Increasing m6A modification resulted in increased hepatoma cell necrosis under glucose deprivation, whereas decreasing m6A modification had an opposite effect. Integrated m6A-seq and RNA-seq revealed potential targets of m6A modification under glucose deprivation, including the transcription factor FOSL1; further, glucose deprivation upregulated FOSL1 by inhibiting FOSL1 mRNA decay in an m6A-YTHDF2-dependent manner through reducing m6A modification in its exon1 and 5'-UTR regions. Functionally, FOSL1 protected hepatoma cells against glucose deprivation-induced necrosis in vitro and in vivo. Mechanistically, FOSL1 transcriptionally repressed ATF3 by binding to its promoter. Meanwhile, ATF3 and MAFF interacted via their leucine zipper domains to form a heterodimer, which competed with NRF2 for binding to antioxidant response elements in the promoters of NRF2 target genes, thereby inhibiting their transcription. Consequently, FOSL1 reduced the formation of the ATF3-MAFF heterodimer, thereby enhancing NRF2 transcriptional activity and the antioxidant capacity of glucose-deprived-hepatoma cells. Thus, FOSL1 alleviated the necrosis-inducing effect of glucose deprivation-induced reactive oxygen species accumulation. Collectively, our study uncovers the protective role of m6A-FOSL1-ATF3 axis in hepatoma cell necrosis under glucose deprivation, and may provide new targets for cancer therapy.

Investigation of heat stress responses and adaptation mechanisms by integrative metabolome and transcriptome analysis in tea plants (Camellia sinensis).

Extreme high temperature has deleterious impact on the yield and quality of tea production, which has aroused the attention of growers and breeders. However, the mechanisms by which tea plant varieties respond to extreme environmental heat is not clear. In this study, we analyzed physiological indices, metabolites and transcriptome differences in three different heat-tolerant tea plant F1 hybrid progenies. Results showed that the antioxidant enzyme activity, proline, and malondialdehyde were significantly decreased in heat-sensitive 'FWS' variety, and the accumulation of reactive oxygen molecules such as H2O2 and O2- was remarkably increased during heat stress. Metabolomic analysis was used to investigate the metabolite accumulation pattern of different varieties in response to heat stress. The result showed that a total of 810 metabolites were identified and more than 300 metabolites were differentially accumulated. Transcriptional profiling of three tea varieties found that such genes encoding proteins with chaperon domains were preferentially expressed in heat-tolerant varieties under heat stress, including universal stress protein (USP32, USP-like), chaperonin-like protein 2 (CLP2), small heat shock protein (HSP18.1), and late embryogenesis abundant protein (LEA5). Combining metabolomic with transcriptomic analyses discovered that the flavonoids biosynthesis pathway was affected by heat stress and most flavonols were up-regulated in heat-tolerant varieties, which owe to the preferential expression of key FLS genes controlling flavonol biosynthesis. Take together, molecular chaperons, or chaperon-like proteins, flavonols accumulation collaboratively contributed to the heat stress adaptation in tea plant. The present study elucidated the differences in metabolite accumulation and gene expression patterns among three different heat-tolerant tea varieties under extreme ambient high temperatures, which helps to reveal the regulatory mechanisms of tea plant adaptation to heat stress, and provides a reference for the breeding of heat-tolerant tea plant varieties.