Search Results (55)

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

Phytoremediation is a green economic method to address soil cadmium (Cd) pollution, and Solanum americanum is considered a potential phytoremediation candidate. However, the underlying Cd response mechanisms of S. americanum remain unclear. In the current study, a hydroponic experiment with 160 μmol/L Cd stress was conducted, physiological and molecular indices were measured to explore the response of S. americanum leaves to Cd stress at different time points (0, 3, and 7 days). Our findings revealed that Cd stress inhibited plant growth. Moreover, Cd stress significantly increased Cd accumulation, as well as Chla content, Chla/b, activities of SOD and POD, and elevated MDA content in the leaves. Furthermore, transcriptomics, proteomics, and metabolomics analyses revealed 17,413 differentially expressed genes (DEGs), 1421 differentially expressed proteins (DEPs), and 229 differentially expressed metabolites (DEMs). Meanwhile, integrative analyses of multi-omics data revealed key proteins involved in response to Cd stress, including POD, PAL, F5H, COMT, and CAD for phenylpropanoid biosynthesis, as well as GAPA, FBP, and FBA for photosynthesis pathways. Additionally, conjoint analyses highlighted that upregulated phenylpropanoid metabolism and photosynthesis alleviated Cd toxicity, playing vital roles in enhancing Cd tolerance in leaves. A conceptual molecular regulatory network of leaves in the response to Cd toxicity was proposed. This comprehensive study will provide detailed molecular-scale insights into the Cd response mechanisms in S. americanum. Full article

Successfully breeding high-yield, lodging-resistant hybrid rice varieties is critical for ensuring food security. Two-line hybrid rice system plays an essential role in rice breeding, and 1892S, an important two-line sterile line, has contributed significantly to the development of over 100 hybrid rice varieties with superior agronomic traits, including lodging resistance. Despite its importance, a comprehensive understanding of the genomic basis underlying these traits in 1892S has been lacking due to the limitations of short-read sequencing technologies. To address this gap, we utilized advanced telomere-to-telomere (T2T) genome assembly techniques to generate a high-quality, gap-free genome of 1892S—the final genome comprises 12 complete chromosomes with 40,560 protein-coding genes. Comparative genomic analysis identified multiple known lodging resistance genes, including SD1, Sdt97, SBI, OsFBA2, APO1, and OsTB1, with unique allelic variations that may enhance resistance. The pan-genome analysis identified 2347 strain-specific genes in 1892S, further supporting its unique genetic advantages. This study represents the complete T2T genome assembly of a two-line sterile line and provides novel insights into the genetic foundation of lodging resistance in hybrid rice. This study highlights the genetic potential of 1892S in hybrid rice breeding and provides a model for the genomic analysis of other two-line sterile lines, offering valuable insights for improving in hybrid rice, including traits lodging resistance, yield stability, and adaptability, which are crucial for global food security. 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

Heparosan, a microbially synthesized capsular polysaccharide, possesses a polysaccharide backbone structurally analogous to heparin. Its biosynthesis holds significant importance for achieving the chemoenzymatic synthesis of heparin. Here, we developed a systematic metabolic engineering strategy in Escherichia coli Nissle 1917 to establish an efficient heparosan production platform. Through the systematic engineering of the glycolytic pathway involving the targeted knockout of zwf, pfkAB, pgi, and fruA (or alternatively fbaA) genes, we generated recombinant strains that lost the capacity to utilize glucose or fructose as sole carbon sources in a minimal medium. This metabolic reprogramming established glycerol as the exclusive carbon source for cell growth, thereby creating a tripartite carbon allocation system, including glycerol for biomass, glucose for UDP-glucuronic acid, and fructose for UDP-N-acetylglucosamine. Therefore, heparosan production was significantly improved from 137.68 mg/L in the wild type to 414.40 mg/L in the recombinant strain. Building upon this foundation, the overexpression of glmM, pgm, and galU genes in the biosynthetic pathway enabled a heparosan titer of 773.78 mg/L in shake-flask cultures. Temporal induction optimization further enhanced titers to 1049.96 mg/L, representing a 7.60-fold enhancement compared to the wild-type strain. This study establishes a triple-carbon-source co-utilization strategy, which holds promising implications for the biosynthesis of heparosan-like microbial polysaccharides. Full article

Soluble sugars and organic acids constitute the primary flavor determinants in fruits and elucidating their metabolic mechanisms provides crucial theoretical foundations for fruit breeding practices and food industry development. Through integrated physiological and transcriptomic analysis of pomegranate varieties ‘Sharp Velvet’ with high acid content and ‘Azadi’ with low acid content, this study demonstrated that the differences in flavor between the two varieties were mainly caused by differences in citric acid content rather than in soluble sugar content. Transcriptome profiling identified 11 candidate genes involved in sugar and acid metabolism, including three genes associated with soluble sugar metabolism (FBA1, SS, and SWEET16) and eight genes linked to organic acid metabolism (ADH1, GABP1, GABP2, GABP3, GABP4, ICL, ME1, and PDC4). These data indicated that differences in citric acid content between the two varieties mainly stemmed from differences in the regulation of the citric acid degradation pathway, which relies mainly on the γ-aminobutyric acid (GABA) branch rather than the isocitric acid lyase (ICL) pathway. Citric acid accumulation in pomegranate fruit was driven by metabolic fluxes rather than vesicular storage capacity. Weighted gene co-expression network analysis (WGCNA) uncovered a significant citric acid content associated module (r = −0.72) and predicted six core transcriptional regulators (bHLH42, ERF4, ERF062, WRKY6, WRKY23, and WRKY28) within this network. Notably, bHLH42, ERF4, and WRKY28 showed significant positive correlations with citric acid content, whereas ERF062, WRKY6, and WRKY23 demonstrated significant negative correlations. Our findings provide comprehensive insights into the genetic architecture governing soluble sugars and organic acids homeostasis in pomegranate, offering both a novel mechanistic understanding of fruit acidity regulation and valuable molecular targets for precision breeding of fruit quality traits. Full article

The R2R3-MYB family of transcription factors (TFs) plays a crucial role in cell specification and secondary metabolism regulation during plant development. In Arabidopsis, MS188, a typical R2R3-MYB protein, is essential for tapetal development and pollen wall formation. However, the nuclear localization sequence (NLS) responsible for directing MS188 into the nucleus has not been fully elucidated. In this study, the subcellular localization of the NLS-containing proteins was determined by GFP tagging in tobacco leaves, and three NLS regions within MS188 were identified: two located at the N-terminus of R2-MYB and one at the C-terminus of R3-MYB. We further narrowed the NLSs located at amino acids (AAs) 12–15, 18–22, and 96–107 via point mutation analysis. Combined with the cytoplasmic protein FBA6, these NLSs fusion proteins could localize in the nucleus. Importantly, the proteins with mutations in AAs 18–22 exhibited completely cytoplasmic signals, whereas other mutated sites partially abolished the nuclear signals. These findings suggest that the NLS at AAs 18–22 is sufficient for nuclear localization. To confirm the NLS functions in vivo, we constructed the vectors including the MS188 gene without the NLS sites, which failed to complement the male sterile phenotype of ms188. We also searched the highly conserved NLSs in other R2R3-MYB TFs and showed they are required for nuclear localization. Collectively, these findings revealed the specific NLS regions within R2R3-MYB transcription factors and highlighted their critical role for subcellular localization in plant developmental regulation. Full article

D-tagatose is an ideal sucrose substitute with potential applications in food and healthcare. The combined catalysis of polyphosphate kinase (PPK), fructose kinase (FRK), D-tagatose-6-phosphate 3-differential anisomerase (FbaA) and phytase provides a low-cost and convenient pathway for the biosynthesis of D-tagatose from D-fructose; however, there is still a problem of low catalytic efficiency that needs to be solved urgently. Therefore, this study enhanced the biosynthesis of D-tagatose by optimizing the expression levels of PPK, FRK and FbaA in a polycistronic system and knocking out the gene pfka of Escherichia coli. With 30 g/L D-fructose as a substrate, the conversion rate increased to 52%, which was the highest after 24 h. In addition, by constructing a multienzyme self-assembly system with SpyTag and SpyCatcher to improve the whole-cell catalytic ability, the conversion rate was further increased to 75%. Finally, through the fed-batch strategy, the optimal strain Ec-7 produced 68.1 g/L D-tagatose from 100 g/L D-fructose. The multienzyme cascade route reported herein provides an efficient and elegant innovative solution for the generation of D-tagatose. Full article

Pyruvate kinase (PK), a pivotal enzyme in glycolysis, serves as a multifunctional regulator of plant growth, development, and stress adaptation. Despite its significance, the functional roles of PKs in peanut remain largely unexplored. Here, we performed a genome-wide identification and systematic characterization of PK genes in cultivated peanut, identifying 21 AhPK genes (AhPK1–AhPK21). Phylogenetic classification divided these genes into two subfamilies: PKc (comprising PKc-1 and PKc-2 subgroups) and PKp (comprising PKp-α and PKp-β subgroups). AhPK members within the same subfamily shared similar motif composition patterns, while genes from different subgroups showed significantly different exon–intron organizations. Collinearity analysis indicated that segmental duplication events and purifying selection predominantly drove the expansion and evolution of the AhPK family. Evolutionary analysis further indicated closer evolutionary relationships between peanut PKs and those of Arabidopsis than with rice. Predicted protein interaction networks suggested that AhPKs can form polymeric protein complexes (e.g., PKp-α and PKp-β) or interact with some important proteins, including FBA4, F14O13.7, APY, DLD, and T16L4.190. Promoter analysis identified abundant cis-regulatory elements associated with light responses, stress responses, hormone responses, and development. Expression pattern analysis demonstrated the significant induction of multiple AhPK genes during seed germination and under polyethylene glycol (PEG)-induced drought stress or abscisic acid (ABA) treatment. Collectively, these findings provide critical insights into the functional roles of AhPK genes in seed germination and drought stress responses, establishing a foundation for future mechanistic studies. Full article

Background: Saline–alkali stress is a major factor limiting the growth of oats. Sugar is the primary carbon and energy source in plants which regulates plant development and growth by regulating enzyme activity and gene expression. Sucrose, glucose, and fructose are ubiquitous plant-soluble sugars that act as signalling molecules in the transcriptional regulation of various metabolic and defence-related genes. Methods: In this study, soluble sugars, fructose, sucrose, and starch contents were measured, and transcriptomics was used to determine the differentially expressed genes (DEGs) in saline-sensitive and saline-tolerant oats after 6, 12, 24, and 48 h. DEGs annotated to carbohydrates were selected using the Kyoto Encyclopedia of Genes and Genomes. Results: DEGs involved in carbohydrate metabolism were mainly enriched in the glycolysis/gluconeogenesis and pentose phosphate pathways, fructose and mannose metabolism, and starch and sucrose metabolism. GAPDH, SUPI, SUS2, ATP-PEK, HXK6, FBA4, TBA4, TKT, ISA3, PPDK1, and BAM2 were significantly expressed, and a quantitative reverse transcription polymerase chain reaction verified the transcriptome sequencing results. Conclusions: In this study, oats with different salinity tolerances were used to determine sugar contents under four salinity stress durations, and transcriptome sequencing was used to explore the regulatory mechanism of sugars and provide a reference for elucidating the sugar signalling regulatory mechanism under abiotic stress. Full article

Dormancy release is an important process for improving the quality of cut-flower lily production and promoting the factory production of lily bulbs. However, the regulatory mechanisms of microRNAs (miRNAs) and their target genes during the dormancy release of lily remain elusive. Anatomy, transcriptomic, molecular biology, and transient transformation techniques involving subcellular localization were applied in our study. There were significant results showing that 0.1 mM riboflavin promoted dormancy release and floral bud differentiation and influenced the flowering time of the Lilium ‘Siberia’. Moreover, some differentially expressed miRNAs and their targets (miR395-y: LoAPS1, miR529-z: LoSPL14, miR396-y: LoCFDP1, miR1863-z: LoFBA3, miR399-y: LoDIT1, and miR11525-z: Lopgm) were identified and predicted. Exogenous riboflavin may activate primary metabolic processes and promote dormancy release in Lilium ‘Siberia’ bulbs. Furthermore, riboflavin upregulated genes related to the riboflavin pathway, H3K4me3 methylation, dormancy control, and the flowering pathway and downregulated dormancy maintenance genes. Moreover, riboflavin promoted endogenous riboflavin and acetyl-CoA accumulation. LoPurple acid phosphatase17 (LoPAP17), a pivotal gene of the riboflavin metabolism pathway, was subsequently cloned. LoPAP17 was most closely related to the orthologous genes of Acorus calamus, Asparagus officinalis, and Musa acuminata. The LoPAP17 protein was subcellularly located in the nucleus. Our study revealed that miRNAs and their target genes might regulate the primary metabolic pathway, promote the accumulation of endogenous riboflavin and acetyl-CoA, and affect protein acetylation during the riboflavin-promoted release of dormancy and flower bud differentiation in the Lilium Oriental hybrid ‘Siberia’. 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

Background/Objectives: Vitamin B₁₂ is very important for human health, as it is a cofactor for enzymatic activities and plays various roles in human physiology. It is highly valued in the pharmaceutical, food, and additive production industries. Some of the bacteria currently used for the vitamin production are difficult to modify with gene-editing tools and may have slow growth. We propose the use of the bacteria Pseudomonas putida KT2440 for the production of vitamin B₁₂ because it has a robust chassis for genetic modifications. The present wok evaluates P. putida KT2440 as a host for vitamin B₁₂ production and explore potential gene-editing optimization strategies. Methods: We curated and modified a genome-scale metabolic model of Pseudomonas putida KT2440 and evaluated different strategies to optimize vitamin B₁₂ production using the knockin and OptGene algorithms from the COBRA Toolbox. Furthermore, we examined the presence of riboswitches as cis-regulatory elements and calculated theoretical biomass growth yields and vitamin B₁₂ production using a flux balance analysis (FBA). Results: According to the flux balance analysis of P. putida KT2440 under culture conditions, the biomass production values could reach 1.802 gDW⁻¹·h¹·L⁻¹, and vitamin B₁₂ production could reach 0.359 µmol·gDW⁻¹·h⁻¹·L⁻¹. The theoretical vitamin B₁₂ synthesis rate calculated using P. putida KT2040 with two additional reactions was 14 times higher than that calculated using the control, Pseudomonas denitrificans, which has been used for the industrial production of this vitamin. Conclusions: We propose that, with the addition of aminopropanol linker genes and the modification of riboswitches, P. putida KT2440 may become a suitable host for the industrial production of vitamin B₁₂. 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

Environmental stresses, including drought stress, seriously threaten food security. Previous studies reported that wheat F-box protein, TaFBA1, responds to abiotic stresses in tobacco. Here, we generated transgenic wheat with enhanced (overexpression, OE) or suppressed (RNA interference, RNAi) expression of TaFBA1. The TaFBA1-OE seedlings showed enhanced drought tolerance, as measured by survival rate and fresh weight under severe drought stress, whereas the RNAi plants showed the opposite phenotype. Furthermore, the OE plants had stronger antioxidant capacity compared to WT and RNAi plants and maintained stomatal opening, which resulted in higher water loss under drought stress. However, stronger water absorption capacity in OE roots contributed to higher relative water contents in leaves under drought stress. Moreover, the postponed stomatal closure in OE lines helped to maintain photosynthesis machinery to produce more photoassimilate and ultimately larger seed size. Transcriptomic analyses conducted on WT and OE plants showed that genes involved in antioxidant, fatty acid and lipid metabolism and cellulose synthesis were significantly induced by drought stress in the leaves of OE lines. Together, our studies determined that the F-box protein TaFBA1 modulated drought tolerance and affected yield in wheat and the TaFBA1 gene could provide a desirable target for further breeding of wheat. Full article