Search Results (32)

Nostoc flagelliforme, a filamentous cyanobacterium inhabiting desert biological soil crusts (BSCs), has developed exceptional strategies to endure extreme environmental stresses, including severe desiccation, intense ultraviolet (UV) radiation, and drastic temperature fluctuations. These organisms must effectively sense and predict environmental changes, particularly the onset of desiccation. This review explores recent advancements in the molecular mechanisms that enable N. flagelliforme to survive under such harsh conditions, with a focus on stress signal sensing, transduction pathways, and photosynthetic adjustments. Key molecular adaptations include the production of extracellular polysaccharide (EPS) sheaths for water retention, the accumulation of compatible solutes like trehalose, and the synthesis of UV-absorbing compounds such as scytonemin and mycosporine-like amino acids (MAAs). Furthermore, N. flagelliforme utilizes a complex signal transduction network, including light-sensing pathways, to regulate responses to rehydration and desiccation cycles. This review emphasizes the integrative nature of N. flagelliforme’s adaptive mechanisms and highlights their potential for biotechnological applications, such as enhancing drought tolerance in crops and advancing ecological restoration in arid regions. Full article

As a type of multicopper oxidase, laccases play multiple biological roles in entomopathogenic fungi, enhancing their survival, development, and pathogenicity. However, the mechanisms by which laccases operate in these fungi remain under-researched. In this study, we identified two laccase-encoding genes, Mr-lac3 and Mr-lcc2, from Metarhizium robertsii, both of which are highly expressed during conidiation. Knocking out Mr-lac3 and Mr-lcc2 resulted in a significant increase in the conidial yields of M. robertsii. Furthermore, the relative expression levels of upstream regulators associated with the conidiation pathway were markedly up-regulated in ΔMr-lac3 and ΔMr-lcc2 compared to the wild-type strain during conidiation, indicating that Mr-lac3 and Mr-lcc2 negatively regulate conidia formation. qRT-PCR analyses revealed that Mr-lac3 and Mr-lcc2 are regulated by the pigment synthesis gene cluster, including Mr-Pks1, Mr-EthD, and Mlac1, and they also provide feedback regulation to jointly control pigment synthesis. Additionally, ΔMr-lac3 and ΔMr-lcc2 significantly reduced the trehalose content in conidia and increased the sensitivity to cell wall-perturbing agents, such as Congo red and guaiacol, which led to a marked decrease in tolerance to abiotic stresses. In conclusion, the laccases Mr-lac3 and Mr-lcc2 negatively regulate conidia formation while positively regulating conidial maturation, thereby enhancing tolerance to abiotic stresses and pathogenicity. Full article

Fatty acid synthase (FAS) is a pivotal gene in the lipid synthesis pathway and plays a crucial role in insect energy metabolism. Locusta migratoria, as one of the major agricultural pests, requires identification of new targets to control or reduce its reproductive capacity for effective locust pest management strategies. In this study, we focused on L. migratoria and identified FAS2 as a potential target gene with functional significance in lipid metabolism and reproduction based on sequence characteristics analysis and tissue-expression patterns of five FAS genes. Subsequently, through RNA interference (RNAi) targeting FAS2 expression, we assessed alterations in lipid and carbohydrate metabolism-related gene expression levels, lipid and carbohydrate contents, ovarian development, and reproductive capacity using experimental techniques such as RT-qPCR, ELISA, and morphological observations. Our findings revealed that interference with FAS2 upregulated genes involved in lipid degradation, including Lsd-1, Lsd-2, Lipase3, and Brummer, while significantly decreasing the TAG content and fat accumulation. At the level of carbohydrate metabolism, FAS2 silencing led to significant upregulation of key genes TPS and GS in the synthesis pathway, resulting in increased glycogen and trehalose content. In addition, FAS2 interference resulted in a significant reduction of Vg mRNA expression level sand protein content in L. migratoria, followed by delayed ovarian development and reduced egg production. This further confirms that impaired FAS2 function prompts L. migratoria to enhance lipid degradation and sugar storage to maintain the energy balance, while reducing the energy investment into reproduction. Collectively, the results of this study suggest that FAS2 can serve as a novel molecular target for controlling L. migratoria. Full article

Auricularia heimuer is drought tolerant, but the mechanism underlying its physiological response to drought has not been systematically studied. We selected 13 strains of A. heimuer and simulated drought stress using a complete yeast medium (CYM) containing 20% polyethylene glycol (PEG), while the medium used for the control treatments did not contain PEG. Strains were cultured on a shaker incubator at 25 °C at 120 rpm for 15 days under dark conditions. The contents of soluble sugars (SS) and soluble proteins (SP), the activities of superoxide dismutase (SOD) and catalase (CAT), the content of malondialdehyde (MDA), and the biomass were measured. Between the 20% PEG treatment and the control, as well as among different strains, there were significant differences in all of the physiological indices. The tested strains were classified into the following four categories according to their membership function values: the first category consisted of the highly drought-tolerant strain A; the second consisted of the drought-tolerant strains A127 and C; the third consisted of the moderately drought-tolerant strains A124, A14, A386, A462, A184, A496, A125, and B; and the fourth consisted of the drought-sensitive strains A356 and A508. Transcriptome analysis was performed on C before and after drought stress treatment, and 1762 differentially expressed genes (DEGs) were obtained, including 798 up- and 964 down-regulated genes. Through KEGG enrichment analysis, it was found for the first time that the synthesis pathway for trehalose in A. heimuer is trehalose phosphate synthase–trehalose phosphate phosphatase (TPS-TPP), which is involved in the response of A. heimuer to drought stress. In addition, two key enzyme genes involved in trehalose synthesis, namely trehalose-6-phosphate synthase (AhTPS) and trehalose-6-phosphate phosphatase (AhTPP), were significantly up-regulated after drought stress. The trehalose content significantly increased in 11 strains after drought stress treatment. This study discovered, for the first time, that the synthesis pathway of trehalose is involved in the response of edible fungi to drought stress, thus providing a reference for the genetic improvement of A. heimuer and the selection of drought-tolerant strains, laying a theoretical foundation for the resistance breeding of other edible fungi. Full article

Salt stress significantly impacts plant growth, and Tamarix ramosissima Ledeb is utilized for afforestation in China’s saline–alkali regions. Trehalose, an osmoregulatory compound, enhances plant tolerance to salt stress by stabilizing cell membranes and regulating oxidative states and ion distribution. However, its role in mitigating NaCl-induced damage in Tamarix species remains understudied. In this study, root samples of T. ramosissima were exposed to NaCl stress with exogenous K⁺ at 0 h, 48 h, and 168 h. Analyses revealed that soluble sugar content increased over time, especially in the 200 mM NaCl + 10 mM KCl treatment at 168 h. Transcriptome sequencing identified 19 trehalose-related genes involved in metabolic and sucrose pathways, with Unigene0015746 notably enhancing D-Glucose 6-phosphate accumulation, a key precursor for trehalose synthesis. This gene emerged as a crucial candidate for further research. The transcriptome data were validated using qRT-PCR. Overall, the study elucidates the molecular mechanisms of trehalose-related genes in T. ramosissima under salt stress with exogenous K⁺, providing valuable genetic resources for breeding salt-tolerant tree species. Full article

Cytochrome P450 monooxygenases (CYP), crucial detoxification enzymes in insects, are involved in the metabolism of endogenous substances as well as the activation and degradation of exogenous compounds. In this study, T. castaneum was utilized to investigate the roles of TcCYP6K1 and TcCYP9F2 genes influencing in the trehalose metabolism pathway under high-CO₂ stress. By predicting the functional sequences of TcCYP6K1 and TcCYP9F2 genes and analyzing their spatiotemporal expression patterns, it was discovered that both genes belong to the CYP3 group and exhibit high expression levels during the larval stage, decreasing during the pupal stage, while showing high expression in the fatty body, intestine, and malpighian tubules. Furthermore, following the knockdown of TcCYP6K1 and TcCYP9F2 genes in combination with treating larvae with 75% CO₂, it was observed that larval mortality increased, and glycogen content significantly decreased, while trehalose content increased significantly. Additionally, membrane-bound trehalase enzyme activity declined, TPS gene expression was significantly upregulated, GS gene expression was significantly downregulated, and ATP content showed a marked decrease. In conclusion, CYP genes are critical responsive genes of T. castaneum to high CO₂ levels, potentially impacting the insect’s resistance to carbon dioxide through their involvement in the synthesis or breakdown of the carbohydrate metabolism pathway. These findings could serve as a theoretical basis for the utilization of novel pesticides in low-oxygen grain storage techniques and offer new insights for environmentally friendly pest control strategies in grain storage. Full article

The salt–tolerant yeast Zygosaccharomyces rouxii is a typical aroma–producing yeast used in food brewing, but its mechanism of high temperature tolerance is still unclear. In this study, the response mechanism of Z. rouxii to glucose under high temperature stress at 40 °C was explored, based on the total synthetic lowest–nutrient medium. The results of the growth curves and scanning electron microscopy showed that high glucose was necessary for Z. rouxii to restore growth under high temperature stress, with the biomass at 300 g/L of glucose (OD_{600, 120h} = 2.44 ± 0.26) being 8.71 times higher than that at 20 g/L (OD_{600, 120h} = 0.28 ± 0.08). The results of the transcriptome analysis, combined with RT–qPCR, showed that the KEGG analysis of differentially expressed genes was enriched in pathways related to glucose metabolism, and high glucose (300 g/L) could effectively stimulate the gene expression of glucose transporters, trehalose synthesis pathways, and xylitol synthesis pathways under a high temperature, especially the expression of the glucose receptor gene RGT2 (up–regulated 193.7 times at 12 h). The corresponding metabolic characteristics showed that the contents of intracellular metabolites, such as glucose (C_{max, 6h} = 6.50 ± 0.12 mg/g DCW), trehalose (C_{max, 8h} = 369.00 ± 17.82 μg/g DCW), xylitol (C_{max, 8h} = 1.79 ± 0.27 mg/g DCW), and glycerol (C_{max, 8h} = 268.10 ± 44.49 μg/g DCW), also increased with time. The accumulation of acetic acid, as the main product of overflow metabolism under high temperature stress (intracellular C_{max, 2h} = 126.30 ± 10.96 μg/g DCW; extracellular C_{max, 12h} = 499.63 ± 27.16 mg/L), indicated that the downstream glycolysis pathway was active. Compared with the normal physiological concentration of glucose, a high glucose concentration can effectively stimulate the gene expression and metabolism of salt–tolerant Z. rouxii under high–temperature conditions to restore growth. This study helps to deepen the current understanding of the thermoadaptive growth mechanism of salt–tolerant Z. rouxii. Full article

The ozone layer (O₃) is essential to the absorption and blocking of UV-B radiation, preventing a large portion from reaching the Earth’s surface. The degradation of the ozone layer (O₃) caused by increased pollution has led to climate change exerting significant influence on natural ecosystems and has resulted in severe stress on the environment, such as an increase in UV-B radiation, which has deleterious effects on plant physiology. UV-B influences the protection pathways that increase compound production, leading to metabolic adjustments and promoting plant acclimatization. This study evaluated whether UV-B application prior to sunlight exposure induces anthocyanin synthesis, photochemical change, and carbohydrate profile modification, contributing to acclimatization in Psidium guajava seedlings. A higher concentration of H₂O₂ may have stimulated anthocyanin synthesis. Furthermore, greater instantaneous water use efficiency (iWUE), the absence of trehalose—a stress marker, and lower concentrations of glucose, fructose, and sucrose indicate that these plants acclimatize when exposed to full sun (30 days). Seedlings exposed to increased UV-B may be more resistant to the climate. The radiation can aid in water resource management with elevated carbohydrate concentrations. These conditions may enhance the success of P. guajava in the field. Therefore, it is suggested that UV-B application to seedlings of P. guajava promotes effective acclimatization, as it activates anthocyanin synthesis, inhibits trehalose accumulation, and increases iWUE. UV-B radiation, depending on its radiance, can be used as a technique in seedling production that can be implanted in anthropic environments. Full article

Rapid cold hardening (RCH) is known to rapidly enhance the cold tolerance of insects. Trehalose has been demonstrated to be a cryoprotectant in Lissorhoptrus oryzophilus, an important invasive pest of rice in China. Trehalose synthesis mainly occurs through the Trehalose-6-phosphate synthase (TPS)/trehalose-6-phosphate phosphatase (TPP) pathway in insects. In this study, the TPS gene from L. oryzophilus (LoTPS) was cloned and characterized for the first time. Its expression and trehalose content changes elicited by RCH were investigated. Our results revealed that RCH not only increased the survival rate of adults but also upregulated the expression level of LoTPS and increased the trehalose content under low temperature. We hypothesized that upregulated LoTPS promoted trehalose synthesis and accumulation to protect adults from low-temperature damage. To further verify the function of the LoTPS gene, we employed RNA interference (RNAi) technology. Our findings showed that RCH efficiency disappeared and the survival rate did not increase when the adults were fed dsRNA of LoTPS. Additionally, inhibiting LoTPS expression resulted in no significant difference in trehalose content between the RCH and non-RCH treatments. Furthermore, the expression patterns of trehalose transporter (TRET) and trehalase (TRE) were also affected. Collectively, these results indicate the critical role of LoTPS in L. oryzophilus cold resistance after RCH induction. LoTPS can enhance survival ability by regulating trehalose metabolism. These findings contribute to further understanding the role of TPS in insect cold resistance and the invasiveness of L. oryzophilus. Moreover, RNAi of LoTPS opens up possibilities for novel control strategies against L. oryzophilus in the future. Full article

Sharp eyespot is a crucial disease affecting cereal plants, such as bread wheat (Triticum aestivum) and barley (Hordeum vulgare), and is primarily caused by the pathogenic fungus Rhizoctonia cerealis. As disease severity has increased, it has become imperative to find an effective and reasonable control strategy. One such strategy is the use of the trehalose analog, validamycin, which has been shown to have a potent inhibitory effect on several trehalases found in both insects and fungi, and is widely used as a fungicide in agriculture. In this study, we demonstrated that 0.5 μg/mL validamycin on PDA plates had an inhibitory effect on R. cerealis strain R0301, but had no significant impact on Fusarium graminearum strain PH-1. Except for its inhibiting the trehalase activity of pathogenic fungi, little is known about its mechanism of action. Six trehalase genes were identified in the genome of R. cerealis, including one neutral trehalase and five acidic trehalase genes. Enzyme activity assays indicated that treatment with 5 μg/mL validamycin significantly reduces trehalase activity, providing evidence that validamycin treatment does indeed affect trehalase, even though the expression levels of most trehalase genes, except Rc17406, were not obviously affected. Transcriptome analysis revealed that treatment with validamycin downregulated genes involved in metabolic processes, ribosome biogenesis, and pathogenicity in the R. cerealis. KEGG pathway analysis further showed that validamycin affected genes related to the MAPK signaling pathway, with a significant decrease in ribosome synthesis and assembly. In conclusion, our results indicated that validamycin not only inhibits trehalose activity, but also affects the ribosome synthesis and MAPK pathways of R. cerealis, leading to the suppression of fungal growth and pesticidal effects. This study provides novel insights into the mechanism of action of validamycin. Full article

The oriental fruit fly, Bactrocera dorsalis (Hendel), is a notorious invasive pest that has raised concerns worldwide. Validamycin has been demonstrated to be a very strong inhibitor against trehalase in a variety of organisms. However, whether validamycin can inhibit trehalase activity to suppress trehalose hydrolysis and affect any other relevant physiological pathways in B. dorsalis remains unknown. In this study, the effects of validamycin injection on the synthesis and metabolism of trehalose and chitin were evaluated. The results show that validamycin injection significantly affected trehalase activity and caused trehalose accumulation. In addition, the downstream pathways of trehalose hydrolysis, including the synthesis and metabolism of chitin, were also remarkably affected as the expressions of the key genes in these pathways were significantly regulated and the chitin contents were changed accordingly. Intriguingly, the upstream trehalose synthesis was also affected by validamycin injection due to the variations in the expression levels of key genes, especially BdTPPC1. Moreover, BdTPPC1 was predicted to have a binding affinity to validamycin, and the subsequent in vitro recombinant enzyme activity assay verified the inhibitory effect of validamycin on BdTPPC1 activity for the first time. These findings collectively indicate that validamycin can be considered as a promising potential insecticide for the management of B. dorsalis. Full article

As the main reserve carbohydrate in garlic, fructan contributes to garlic’s yield and quality formation. Numerous studies have shown that plant fructan metabolism induces a stress response to adverse environments. However, the transcriptional regulation mechanism of garlic fructan in low-temperature environments is still unknown. In this study, the fructan metabolism of garlic seedlings under low-temperature stress was revealed by transcriptome and metabolome approaches. With the extension of stress time, the number of differentially expressed genes and metabolites increased. Using weighted gene co-expression network analysis (WGCNA), three key enzyme genes related to fructan metabolism were screened (a total of 12 transcripts): sucrose: sucrose 1-fructosyltransferase (1-SST) gene; fructan: fructan 6G fructosyltransferase (6G-FFT) gene; and fructan 1-exohydrolase (1-FEH) gene. Finally, two hub genes were obtained, namely Cluster-4573.161559 (6G-FFT) and Cluster-4573.153574 (1-FEH). The correlation network and metabolic heat map analysis between fructan genes and carbohydrate metabolites indicate that the expression of key enzyme genes in fructan metabolism plays a positive promoting role in the fructan response to low temperatures in garlic. The number of genes associated with the key enzyme of fructan metabolism in trehalose 6-phosphate was the highest, and the accumulation of trehalose 6-phosphate content may mainly depend on the key enzyme genes of fructan metabolism rather than the enzyme genes in its own synthesis pathway. This study not only obtained the key genes of fructan metabolism in garlic seedlings responding to low temperatures but also preliminarily analyzed its regulatory mechanism, providing an important theoretical basis for further elucidating the cold resistance mechanism of garlic fructan metabolism. Full article

This study aimed to isolate, screen the plant-growth-enhancing features, and explore the whole-genome sequence of AZC66 isolated from the rhizosphere of Zygophyllum coccineum and determine its biostimulating effects on the growth of cowpea under greenhouse conditions. Salkowski reagent was used to measure AZC66’s indole acetic acid production. AZC66’s inorganic phosphate solubility on Pikovskaya agar was evaluated using tricalcium phosphate. The results indicated the ability of AZC66 to fix nitrogen, produce IAA (66.33 ± 0.44 μg mL⁻¹), solubilize inorganic phosphate, and exhibit the activity of ACC deaminase (278.40 ± 21 mol -ketobutyrate mg⁻¹ h⁻¹). Cowpea’s root and shoot dry weights were also significantly increased after in vitro inoculation with AZC66. The identity of AZC66 was confirmed as Priestia filamentosa, and 4840 genes were predicted in its genome. The gene sequences were compared against the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, and the results showed that the top three pathways wherein the maximum number of genes are involved are signaling and cellular processes, genetic information processing, and carbohydrate metabolism. The genome sequencing of the strain AZC66 revealed a number of genes implicated in plant biostimulation activities such as nitrogen fixation (nifU), phytohormone synthesis (trpAB genes), phosphate solubilization (PhbCEF, pstABCS, and phoU), and siderophore formation (FbpA, feoAB, and fetB). The AZC66 genome contained numerous genes involved in nitrogen metabolism, nitrogen regulation, and the nitrate reduction pathway. The phenazine biosynthetic gene in AZC66 demonstrated biocontrol and soil survival properties. The trehalose synthesis genes in AZC66 may help plants resist osmotic and salt stress. The discovery of glycine betaine, cold shock, and heat shock protein genes demonstrated that AZC66 could withstand harsh conditions. AZC66 might be used to create robust, sustainable biological fertilizers for future agricultural use in Saudi Arabia. Furthermore, the predicted adaptable metabolic pathways might serve as the basis for potential biotechnological applications in agriculture and industry. Full article

Saline-alkali stress seriously affects the yield and quality of crops, threatening food security and ecological security. Improving saline-alkali land and increasing effective cultivated land are conducive to sustainable agricultural development. Trehalose, a nonreducing disaccharide, is closely related to plant growth and development and stress response. Trehalose 6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP) are key enzymes catalyzing trehalose biosynthesis. To elucidate the effects of long-term saline-alkali stress on trehalose synthesis and metabolism, we conducted an integrated transcriptome and metabolome analysis. As a result, 13 TPS and 11 TPP genes were identified in quinoa (Chenopodium quinoa Willd.) and were named CqTPS1-13 and CqTPP1-11 according to the order of their Gene IDs. Through phylogenetic analysis, the CqTPS family is divided into two classes, and the CqTPP family is divided into three classes. Analyses of physicochemical properties, gene structures, conservative domains and motifs in the proteins, and cis-regulatory elements, as well as evolutionary relationships, indicate that the TPS and TPP family characteristics are highly conserved in quinoa. Transcriptome and metabolome analyses of the sucrose and starch metabolism pathway in leaves undergoing saline-alkali stress indicate that CqTPP and Class II CqTPS genes are involved in the stress response. Moreover, the accumulation of some metabolites and the expression of many regulatory genes in the trehalose biosynthesis pathway changed significantly, suggesting the metabolic process is important for the saline-alkali stress response in quinoa. Full article

Deinococcus radiodurans is a microorganism that can adjust, survive or thrive in hostile conditions and has been described as “the strongest microorganism in the world”. The underlying mechanism behind the exceptional resistance of this robust bacterium still remains unclear. Osmotic stress, caused by abiotic stresses such as desiccation, salt stress, high temperatures and freezing, is one of the main stresses suffered by microorganisms, and it is also the basic response pathway by which organisms cope with environmental stress. In this study, a unique trehalose synthesis-related gene, dogH (Deinococcus radiodurans orphan glycosyl hydrolase-like family 10), which encodes a novel glycoside hydrolase, was excavated using a multi-omics combination method. The content accumulation of trehalose and its precursors under hypertonic conditions was quantified by HPLC-MS. Ours results showed that the dogH gene was strongly induced by sorbitol and desiccation stress in D. radiodurans. DogH glycoside hydrolase hydrolyzes α-1,4-glycosidic bonds by releasing maltose from starch in the regulation of soluble sugars, thereby increasing the concentration of TreS (trehalose synthase) pathway precursors and trehalose biomass. The maltose and alginate content in D. radiodurans amounted to 48 μg mg protein⁻¹ and 45 μg mg protein⁻¹, respectively, which were 9 and 28 times higher than those in E. coli, respectively. The accumulation of greater intracellular concentrations of osmoprotectants may be the true reason for the higher osmotic stress tolerance of D. radiodurans. Full article