Search Results (70)

Investigating the physiological responses and resistance mechanisms in plants under drought stress provides critical insights for optimizing irrigation water utilization efficiency and promoting the development of irrigation science. In this study, cotton seedlings were cultivated in a light incubator. Three drought stress levels were applied: mild (M1, 50–55% field moisture), moderate (M2, 45–50%), and severe (M3, 40–45%). Transcriptome analysis was performed under mild and severe stress. The results revealed that differentially expressed genes (DEGs) related to proline degradation were down-regulated and proline content increased in cotton. Under different stress treatments, cotton exhibited a stress-intensity-dependent regulation of carbohydrate metabolism and soluble sugar content decreased and then increased. And the malondialdehyde content analysis revealed a dose-dependent relationship between stress intensity and membrane lipid peroxidation. Stress activated the antioxidant system, leading to the down-regulation of DEGs for reactive oxygen species production in the mitogen-activated protein kinase (MAPK) signaling pathway. Concurrently, superoxide dismutase activity and peroxidase content increased to mitigate oxidative damage. Meanwhile, the photosynthetic performance of cotton seedlings was inhibited. Chlorophyll content, stomatal conductance, the net photosynthetic rate, the transpiration rate and water use efficiency were significantly reduced; intercellular carbon dioxide concentration and leaf stomatal limitation value increased. But photosynthesis genes (e.g., PSBO (oxygen-evolving enhancer protein 1), RBCS (ribulose bisphosphate carboxylase small chain), and FBA2 (fructose-bisphosphate aldolase 1)) in cotton were up-regulated to coordinate the photosynthetic process. Furthermore, cotton seedlings differentially regulated key biosynthesis and signaling components of phytohormonal pathways including abscisic acid, indoleacetic acid and gibberellin. This study elucidates the significant gene expression of drought-responsive transcriptional networks and relevant physiological response in cotton seedlings and offers a theoretical basis for developing water-saving irrigation strategies. Full article

Fructose-1,6-bisphosphate aldolase (FBA; EC 4.1.2.13) is a key enzyme in glycolysis and the Calvin cycle, which plays crucial roles in carbon allocation and plant growth. The FBA family genes (FBA s) have been identified in several plants. However, their presence and roles in sweet potato remain unexplored. In this study, a total of 20 FBAs were identified in sweet potato and its wild wild diploidrelatives, including seven in sweet potato (Ipomoea batatas, 2n = 6x = 90), seven in I. trifida (2n = 2x = 30), and six in I. triloba (2n = 2x = 30). Their protein physicochemical properties, chromosomal localization, phylogenetic relationship, gene structure, promoter cis-elements, and expression patterns were systematically analyzed. The conserved genes and protein structures suggest a high degree of functional conservation among FBA genes. IbFBAs may participate in storage root development and starch biosynthesis, especially IbFBA1 and IbFBA6, which warrant further investigation as candidate genes. Additionally, the FBAs could respond to drought and salt stress. They are also implicated in hormone crosstalk, particularly with ABA and GA. This work provides valuable insights into the structure and function of FBAs and identifies candidate genes for improving yield, starch content, and abiotic stress tolerance in sweet potatoes. Full article

Salt stress severely impairs photosynthesis and development in tomato seedlings. This study investigated the regulatory role of exogenous melatonin (MT) on photosynthetic performance under salt stress by determining chlorophyll content, chlorophyll a fluorescence parameters, Calvin cycle enzyme activities, and related gene expression. Results showed that salt stress significantly reduced chlorophyll content and impaired photosystem II (PSII) functionality, as evidenced by the increased minimum fluorescence (F_o) and decreased maximum quantum efficiency of PSII (F_v/F_m) and effective PSII quantum yield (Φ_PSII). MT application mitigated these negative effects, as reflected by higher F_v/F_m, increased chlorophyll content, and lower non-photochemical quenching (NPQ). In addition, MT-treated plants exhibited improved PSII electron transport and more efficient use of absorbed light energy, as shown by elevated Φ_PSII and qP values. These changes suggest improved PSII functional stability and reduced excess thermal energy dissipation. Furthermore, MT significantly enhanced both the activity and expression of key enzymes involved in the Calvin cycle, including ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), Rubisco activase (RCA), phosphoglycerate kinase (PGK), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), fructose-1,6-bisphosphatase (FBPase), fructose-bisphosphate aldolase (FBA), transketolase (TK), and sedoheptulose-1,7-bisphosphatase (SBPase), thereby promoting carbon fixation and ribulose-1,5-bisphosphate (RuBP) regeneration under salt stress. Conversely, inhibition of endogenous MT synthesis by p-CPA exacerbated salt stress damage, further confirming MT’s crucial role in salt tolerance. These findings demonstrate that exogenous MT enhances salt tolerance in tomato seedlings by simultaneously improving photosynthetic electron transport efficiency and upregulating the activity and gene expression of key Calvin cycle enzymes, thereby promoting the coordination between light reactions and carbon fixation processes. This study provides valuable insights into the comprehensive regulatory role of MT in maintaining photosynthetic performance under saline conditions. Full article

Drought deficit inhibits oat growth and yield. Fulvic acid (FA) can enhance plant stress tolerance, but its effects on regulating the ascorbate–glutathione cycle, chlorophyll synthesis, and carbon–assimilation ability remain unclear. Therefore, this study aimed to elucidate the physiological mechanisms of the FA regulation of drought tolerance in oats and its relationship with growth and yield using the drought-resistant variety Yanke 2 and the drought-sensitive variety Bayou 9. The effects of FA on growth and yield, the antioxidant system, chlorophyll synthesis, and carbon–assimilation capacity of oats under drought stress were investigated by systematically assessing changes in morphogenesis, ascorbate–glutathione cycle, chlorophyll and its intermediates, carbon–assimilation enzyme activities, and carbohydrate metabolism. The results showed that under drought stress, FA treatment significantly promoted oat growth (leaf area, dry matter) and yield, elevated glutathione peroxidase, ascorbate peroxidase, glutathione reductase, and dehydroascorbate reductase activities, reduced ascorbic acid, and reduced glutathione content. In addition, FA increased chlorophyll, as well as magnesium protoporphyrin IX, protoporphyrin IX, and protochlorophyllin acid ester content, enhanced 1,5-bisphosphate ribulose carboxylase, 1,5-bisphosphate ribulose carboxylase enzyme, 1,7-bisphosphate sestamibiose heptulose esterase, 1,6-bisphosphate fructose aldolase, sucrose synthase, sucrose phosphate synthase, acid invertase, and neutral invertase activities, and increased sucrose, glucose, and fructose content. Overall, fulvic acid (FA) alleviates drought-induced damage in oats by enhancing the ascorbate–glutathione cycle, promoting chlorophyll biosynthesis, and improving carbon assimilation and carbohydrate metabolism. The drought-sensitive variety (Yanke 2) was more effective in application compared to the drought-resistant variety (Bayou 9). This research provides valuable insight into its potential as a biostimulant under abiotic stress. Full article

Sub-optimal light environments in controlled agricultural settings often limit the productivity of plants. While LED supplementary lighting has been widely adopted to mitigate light deficiencies, the spatial arrangement of LED light sources remains a critical but under-explored factor affecting plant physiological responses. In this study, we used the affiliation function method to comprehensively analyze the effects of four spatial LED supplementary lighting configurations—top-down lighting (T1), mid-canopy upward lighting (T2), mid-canopy downward lighting (T3), and bottom-up lighting (T4)—on the growth and photosynthetic performance of tomato plants. Our findings reveal that the T1 treatment significantly increased light absorption in the upper and middle leaves, enhanced photosynthetic efficiency, promoted the CO₂ assimilation rate, and elevated the activities of key Calvin cycle enzymes, including ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), fructose-1,6-bisphosphatase (FBPase), transketolase (TK), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and fructose-1,6-bisphosphate aldolase (FBA). These changes led to improved carbohydrate metabolism and biomass accumulation. Additionally, the T4 treatment markedly enhanced photosynthetic activity in the lower leaves, increasing sugar metabolism-related enzyme activities, such as sucrose synthase (SS), sucrose phosphate synthase (SPS), acid invertase (AI), and neutral invertase (NI). Consequently, compared with the CK treatment, the T4 treatment significantly increased the accumulation of glucose, fructose, and sucrose, with increases of 47.36%, 27.61%, and 87.21%, respectively. Furthermore, LED supplementation regulated endogenous hormone levels, thereby promoting overall plant growth. This study highlights the importance of the spatial arrangement of LEDs in optimizing light distribution and enhancing plant productivity, providing valuable theoretical and practical insights for improving agricultural practices in controlled environments. Full article

Previously, we reported that mating induces an early transcriptional response in the oviductal mucosa of rats. The functional category ‘cell-to-cell signaling and interaction’ was overrepresented in this gene list. Therefore, in the present study, we describe the role of one of these genes, carbohydrate sulfotransferase 10 (Chst10), in the oviductal mucosa. CHST10 participates in the synthesis of the carbohydrate moiety human natural killer-1 (HNK-1), which mediates cell-to-cell interactions. When using one-dimensional Western blot and sulfotransferase analyses, we found that mating increased the protein level and activity of CHST10 in the oviductal mucosa at 3 h after stimulation. A two-dimensional Western blot analysis and mass spectrometry were used to identify the novel HNK-1 glycoproteins aldehyde dehydrogenase 9 family, member A1 (ALDH9A1), fructose bisphosphate aldolase A (ALDOA), and four and a half LIM domains protein 1 (FHL1) in the oviductal mucosa, and we found that mating induces the synthesis of their acidic variants. Interestingly, in the utero-tubal junction (UTJ), acrosome-reacted sperm apparently were interacting with regions in which ALDH9A1 and HNK-1 signals overlap. Furthermore, vaginocervical stimulation applied to unmated rats increased the mRNA level of Chst10 in the oviductal mucosa. In conclusion, mating increases the activity of CHST10 in the oviductal mucosa, which in turn induces the synthesis of acidic variants of ALDH9A1 and FHL1 via HNK-1 glycosylation. ALDH9A1, HNK-1-ALDH9A1, and/or other HNK-1 glycoproteins could participate in the negative selection of sperm in the UTJ, since we detected acrosome-reacted sperm apparently interacting with regions where these proteins are located. Finally, the sensorial component of mating could regulate early events (e.g., sperm transport and selection) occurring in the oviductal mucosa after mating. Full article

M. oleifera leaves represent a novel and nutritious food. Prior research has demonstrated that M. oleifera leaves can elicit allergic responses in BALB/c mice. Based on these findings, further studies were conducted to investigate the effects of heat treatment on the allergenicity, particle size, zeta potential, total sulfhydryl (TSH) content, hydrophilicity and hydrophobicity, ultraviolet spectrum, and intrinsic fluorescence spectrum of M. oleifera leaf protein. Additionally, in vitro digestion experiments were carried out to gain further insights into the protein’s behavior under these conditions. The experiment simulated the alterations in M. oleifera leaf protein during the processes of cooking and digestion. The findings of this experiment can provide certain guidance for the processing of M. oleifera leaf products. The hydrophilicity, hydrophobicity, transmembrane region, antigen index, calcium binding site, spatial structure, and homology of M. oleifera leaf fructose 1,6 bisphosphate aldolase (FBA) were simulated and calculated based on the amino acid sequence of the 36 kDa allergen. These parameters collectively serve to indicate the allergenic activity of the peptide. The findings of the analysis align with the outcomes of the sensitization experiments, suggesting that the FBA of M. oleifera leaves is indeed consistent. In conjunction with the heat treatment experiments, this research can inform the preparation of M. oleifera leaf foods and provide a foundation for further investigation into M. oleifera leaf allergens. Full article

The pentose phosphate pathway (PPP) is essential for human health and provides, amongst others, the reduction power to cope with oxidative stress. In contrast to the model baker’s yeast, the PPP also contributes to a large extent to glucose metabolism in the milk yeast Kluyveromyces lactis. Yet, the physiological consequences of mutations in genes encoding PPP enzymes in K. lactis have been addressed for only a few. We here embarked on a systematic study of such mutants, deleting ZWF1, SOL4, GND1, RKI1, RPE1, TKL1, TAL1, and SHB17. Interestingly, GND1, RKI1, and TKL1 were found to be essential under standard growth conditions. Epistasis analyses revealed that a lack of Zwf1 rescued the lethality of the gnd1 deletion, indicating that it is caused by the accumulation of 6-phosphogluconate. Moreover, the slow growth of a tal1 null mutant, which lacks fructose-1,6-bisphosphate aldolase, was aggravated by deleting the SHB17 gene encoding sedoheptulose-1,7-bisphosphatase. A mitotically stable tetOFF system was established for conditional expression of TAL1 and TKL1, encoding transaldolase and transketolase in the non-oxidative part of the PPP, and employed in a global proteome analysis upon depletion of the enzymes. Results indicate that fatty acid degradation is upregulated, providing an alternative energy source. In addition, tal1 and tkl1 null mutants were complemented by heterologous expression of the respective genes from baker’s yeast and humans. These data demonstrate the importance of the PPP for basic sugar metabolism and oxidative stress response in K. lactis and the potential of this yeast as a model for the study of PPP enzymes from heterologous sources, including human patients. Full article

Different types of microRNA participate in the post-transcriptional regulation of target genes. The content of several hypoxia-dependent miRNAs in plant cells, including miR775, increases in the conditions of oxygen deficiency. Electrophoretic studies of total RNA samples from the leaves of flooded seedlings of maize (Zea mays L.) revealed the presence of two interfering complexes with miR775 at 12 h of hypoxic incubation. A nucleotide sequence analysis of a sample containing the interfering complex of miR775 with mRNA from maize leaves showed a high degree of homology with the ICL/PEPM_KPHMT lyase family domain. It corresponded to a fragment of fructose-1,6-bisphosphate aldolase mRNA. By real-time PCR, we established the dynamics of the content of transcripts of aldolase isoenzyme genes under hypoxia in maize leaves. A decrease in the transcriptional activity of the aldolase 1 gene (Aldo1) correlated with a high content of miR775 in maize leaf cells. The fraction of extracellular vesicles sedimented at 100,000× g, was enriched with miR775. The accumulation of aldolase 2 (Aldo2) mRNA transcripts under hypoxic conditions indicates its participation in maintaining glycolysis when Aldo1 expression is inhibited. We conclude that an increase in the total content of free miR775 and its participation in the suppression of the Aldo1 gene represents an important mechanism in developing the adaptive reaction of cellular metabolism in response to hypoxia. Full article

Schizochytrium limacinum SR21, a kind of eukaryotic heterotrophic organism rich in unsaturated fatty acids, is an emerging microbial alternative to fish oil. The dietary inclusion of 15% SR21 was optimal for the growth performance of zebrafish. Previous studies demonstrated that fructose-1,6-bisphosphate aldolase (FBA) of Edwardsiella tarda is a valuable broad-spectrum antigen against various pathogens in aquaculture (e.g., Aeromonas hydrophila, Vibro anguillarum, Vibro harveyi, Vibro alginolyticus). We pioneered the development of stable S. limacinum SR21 transformants expressing the antigen protein FBA, exploring their potential as a novel oral vaccine for the aquaculture industry. The model animal zebrafish (Danio rerio) and ornamental fish koi carp (Cyprinus carpio koi) were harnessed to assess the immunoprotective effect, respectively. According to the quantitative expression analysis, zebrafish fed with recombinant Schizochytrium expressing FBA exhibited specific immune responses in the intestine. The expression levels of MHC-I and MHC-II, involved in cell-mediated adaptive immune responses, were significantly upregulated on the 14th and 28th days post-immunization. Additionally, the expression of highly specialized antibody genes IgZ1 and IgZ2 in mucosal immunity were significantly triggered on the 14th day post-immunization. Feeding koi carp with recombinant S. limacinum SR21-FBA increased the production of myeloperoxidase and FBA-specific antibodies in the sera. Furthermore, the sera of koi fed with recombinant S. limacinum SR21-FBA exhibited significant bactericidal activities against pathogen E. tarda. Thus, S. limacinum SR21 is a natural and highly promising oral vaccine carrier that not only provides essential nutrients as a functional feed ingredient but also offers specific immune protection to aquatic animals. This dual application is vital for promoting the sustainable development of the aquaculture industry. Full article

Heartworm disease, caused by Dirofilaria immitis, is a vector-borne zoonotic disease, (mainly affecting canids and felids) causing chronic vascular and pulmonary pathology in its early stages, which worsens with parasite load and/or death of adult worms in the pulmonary artery or right heart cavity, and can be fatal to the host. Angiogenesis is a mechanism by which new blood vessels are formed from existing ones. The aim of this work was to study the effect of two molecules of the D. immitis excretory/secretory antigen (DiES) on the angiogenic process, taking into account that this antigen is able to interact with this process and use it as a survival mechanism. For this purpose, an in vitro model of endothelial cells was used and treated with two recombinant proteins, i.e., actin (Act) and fructose-bisphosphate aldolase (FBAL) proteins belonging to DiES, and both pro- and antiangiogenic molecules were analyzed, as well as the cellular processes of cell proliferation, migration, and pseudocapillary formation. Act and FBAL proteins, together with vascular endothelial growth factor (VEGF-A), as an angiogenic precursor, are able to stimulate the production of proangiogenic factors as well as cellular processes of proliferation, migration, and pseudocapillary formation. This implies that these molecules could be produced by D. immitis to facilitate its survival, and the relationship between parasite and canine host would be further elaborated. Full article

Flooding stress poses a significant challenge to soybean cultivation, impacting plant growth, development, and ultimately yield. In this study, we investigated the responses of two distinct soybean cultivars: flooding-tolerant Nanxiadou 38 (ND38) and flooding-sensitive Nanxiadou 45 (ND45). To achieve this, healthy seedlings were cultivated with the water surface consistently maintained at 5 cm above the soil surface. Our objective was to elucidate the physiological and molecular adaptations of the two cultivars. Under flooding stress, seedlings of both cultivars exhibited significant dwarfing and a notable decrease in root length. While there were no significant differences in the dry weight of aboveground shoots, the dry weight of underground shoots in ND38 was strikingly decreased following flooding. Additionally, total chlorophyll content decreased significantly following flooding stress, indicating impaired photosynthetic performance of the cultivars. Moreover, malondialdehyde (MDA) levels increased significantly after flooding, particularly in the ND45 cultivar, suggesting heightened oxidative stress. Expression analysis of methylation and demethylation genes indicated that MET1 and DME play crucial roles in response to flooding stress in soybeans. Meanwhile, analysis of the hemoglobin family (GLBs), aquaporin family (AQPs), glycolytic pathway-related genes, and NAC transcription factor-related genes identified GLB1-1 and GLB1-2, GLB2-2, PIP2-6, PIP2-7, TIP2-2, TIP4-1, TIP5-1, Gm02G222400 (fructose-bisphosphate aldolase), Gm19G017200 (glucose-6-phosphate isomerase), and Gm04G213900 (alcohol dehydrogenase 1) as key contributors to flooding tolerance in both soybean cultivars. These findings provide crucial insights into the physiological and molecular mechanisms underlying flooding tolerance in soybeans, which could guide future molecular breeding strategies for the development of flooding-tolerant soybean cultivars. Full article

Brucellosis is a bacterial zoonosis caused by the genus Brucella, which mainly affects domestic animals. In these natural hosts, brucellae display a tropism towards the reproductive organs, such as the placenta, replicating in high numbers and leading to placentitis and abortion, an ability also exerted by the B. melitensis live-attenuated Rev1 strain, the only vaccine available for ovine brucellosis. It is broadly accepted that this tropism is mediated, at least in part, by the presence of certain preferred nutrients in the placenta, particularly erythritol, a polyol that is ultimately incorporated into the Brucella central carbon metabolism via two reactions dependent on transaldolase (Tal) or fructose-bisphosphate aldolase (Fba). In the light of these remarks, we propose that blocking the incorporation of erythritol into the central carbon metabolism of Rev1 by deleting the genes encoding Tal and Fba may impair the ability of the vaccine to proliferate massively in the placenta. Therefore, a Rev1ΔfbaΔtal double mutant was generated and confirmed to be unable to use erythritol. This mutant exhibited a reduced intracellular fitness both in BeWo trophoblasts and THP-1 macrophages. In the murine model, Rev1ΔfbaΔtal provided comparable protection to the Rev1 reference vaccine while inducing fewer adverse reproductive events in pregnant animals. Altogether, these results postulate the Rev1ΔfbaΔtal mutant as a reproductively safer Rev1-derived vaccine candidate to be studied in the natural host. Full article

Light, as a crucial environmental determinant, profoundly influences the synthesis of secondary metabolites in plant metabolism. This study investigated the impacts of the red light combined with ultraviolet-A (UV-A) and ultraviolet-B (UV-B) treatments on phenolic acid biosynthesis in black wheat seedlings. The results demonstrate that the red light combined with UV-A and UV-B treatments significantly enhanced the levels of phenolic acids in black wheat seedlings, at 220.4 μg/seedling and 241.5 μg/seedling, respectively. The content of bound phenolic acids in black wheat seedlings increased by 36.0% under the UV-B treatment. The application of the UV-A/UV-B treatments markedly enhanced the activities of phenylalanine ammonia-lyase, 4-coumarate CoA ligase, and cinnamate 4-hydroxylase in black wheat seedlings while also promoting the expression levels of genes related to phenolic acid synthesis. The expression levels of fructose-1,6-bisphosphate aldolase and NADP-malic enzyme related to photosynthesis were significantly upregulated. This resulted in an augmentation in the chlorophyll content, thereby enhancing photosynthesis in black wheat seedlings. Nevertheless, the UV-A and UV-B treatments also had a significant constraining effect on the growth and development of black wheat seedlings. In addition, the UV-A and UV-B treatments increased the activity and gene expression levels of antioxidant enzymes while significantly increasing the contents of total flavonoids and anthocyanins, activating the antioxidant system. The findings reveal that light-source radiation serves as an effective method for promoting the biosynthesis of phenolic acids in black wheat seedlings. Full article

The fructose-1,6-bisphosphate aldolase (FBA) gene family exists in higher plants, with the genes of this family playing significant roles in plant growth and development, as well as response to abiotic stresses. However, systematic reports on the FBA gene family and its functions in cucumber are lacking. In this study, we identified five cucumber FBA genes, named CsFBA1-5, that are distributed randomly across chromosomes. Phylogenetic analyses involving these cucumber FBAs, alongside eight Arabidopsis FBA proteins and eight tomato FBA proteins, were conducted to assess their homology. The CsFBAs were grouped into two clades. We also analyzed the physicochemical properties, motif composition, and gene structure of the cucumber FBAs. This analysis highlighted differences in the physicochemical properties and revealed highly conserved domains within the CsFBA family. Additionally, to explore the evolutionary relationships of the CsFBA family further, we constructed comparative syntenic maps with Arabidopsis and tomato, which showed high homology but only one segmental duplication event within the cucumber genome. Expression profiles indicated that the CsFBA gene family is responsive to various abiotic stresses, including low temperature, heat, and salt. Taken together, the results of this study provide a theoretical foundation for understanding the evolution of and future research into the functional characterization of cucumber FBA genes during plant growth and development. Full article