Search Results (3,188)

High levels of antimony (Sb) adversely affect plant growth and development. We aimed to uncover the harmful effects of different forms of Sb on root morphology, physiology and expression profiles of genes encoding functions associated with roots. Rice plants grown in ½ Hoagland nutrient solution were exposed to Sb(III) and Sb(V) at concentrations of 10 and 20 mgL⁻¹ for one week. Results demonstrated that higher concentrations of Sb(III) significantly impaired root morphological traits, with high toxicity observed at 20 mgL⁻¹ Sb(III) and 10 mgL⁻¹ Sb(V). The application of Sb(III) led to reduced uronic acid levels in hemicellulose-II (HCII) with cell organelle and cytosol displaying substantial accumulation of Sb(III). Enzymatic activity revealed that high levels of Sb(III) disrupted the activity of cellulase (CE) and pectin methylesterase (PME), while augmenting the activity of Xyloglucan endotransglycosylase hydrolase (XTH). Additionally, polygalacturonase (PG) was significantly reduced under Sb(V) 10 mgL⁻¹ exposure. Pearson’s correlation coefficient was used for continuous data to draw a linear trend between studied parameters. Shoot biomass displayed a negative correlation with root and shoot Sb. Shoot XTH had a positive correlation with shoot Sb. Furthermore, root and shoot Sb showed a positive association with root diameter and XTH. Hemicellulose-1 (HCI) was negatively associated with PME, PG and pectin, suggesting that HCI was a suitable binding site for uronic acid in the context of Sb contamination. Additionally, to elucidate the molecular mechanisms underlying root structural alterations, the expression profiles of key cell wall-related genes—Expansin, Cellulase synthase, XTH8 (xyloglucan endotransglucosylase/hydrolases) and Pectinesterase—were systematically analyzed using qRT-PCR. All genes were up-regulated in response to different forms of Sb exhibiting resistance. Xylanase was down-regulated, showing its role in the containment of Sb in roots. Further studies are advised for elucidating the mechanism of action of Sb on different tissues of rice plants. Full article

Cr(VI) pollution severely damages plant cell wall structure and membrane integrity. Proline-rich proteins (PRPs), key cell wall structural components, rely on proline as their biosynthetic precursor. Pro accumulation has been shown to positively correlate with PRP abundance, suggesting a direct biochemical link between exogenous Pro [Pro_(exo)] application and PRP-mediated cell wall function. However, how Pro_(exo) regulates PRP expression to maintain cell wall structural integrity and membrane stability in rice seedlings under Cr(VI) stress remains unclear. In this study, the subcellular distribution of Cr, electrolyte leakage (EL), cell wall thickness, and the expression of PRP genes in rice seedlings were evaluated. The results revealed that Cr(VI) stress induced significant increases in EL and changes in cell wall thickness in rice seedling cells (p < 0.05). The application of Pro_(exo) significantly mitigated EL and increased cell wall thickness (p < 0.05). Furthermore, Pro_(exo) markedly increased the sequestration of Cr within the seedling root cell walls while reducing its distribution in the cytoplasm and organelles of seedling shoot cells (p < 0.05). Phylogenetic analysis of 48 OsPRP genes, on the basis of their homology with seven functionally characterized PRPs from other species, revealed 12 candidate genes in rice potentially involved in the regulation of cell membrane stability, cell wall assembly, thickening, and integrity. Subsequent qRT-PCR analysis and gene expression variation factor calculation revealed that Pro_(exo) significantly promoted the expression of OsPRP1.1, OsPRP3, OsRePRP2.1, OsHyPRP18, and OsHyPRP27 in roots and that of OsHyPRP27 in the shoots of rice seedlings under Cr(VI) stress. These findings indicate that Pro_(exo) enhances Cr compartmentalization within the root cell wall and improves membrane stability, thereby contributing to Cr(VI) tolerance in plants through the modulation of these key PRP genes. Our findings provide novel insights into the mechanism by which Pro_(exo) regulates PRP expression to affect plant cellular structural stability and heavy metal tolerance. Full article

Members of the yellow gene family encode conserved Yellow proteins with diverse roles in insect pigmentation, cuticle formation, and reproduction, making them promising targets for RNA interference (RNAi)-mediated pest control strategies. However, little is known about their phylogeny and functions in the brown planthopper (Nilaparvata lugens), a devastating rice pest that serves as a vector for viral rice diseases. Here, we identified and characterized 11 yellow genes in N. lugens, which showed distinct structures and expression profiles. Phylogenetic analysis revealed that N. lugens has retained orthologs of yellow-y, -b, -d, -e, -g, -g2, -h, and -x but lacks those of yellow-c and -f, suggesting lineage-specific gene loss. Nine of the eleven NlYellow genes were localized to chromosome 8, with several positioned in close genomic proximity. The clustering of these loci suggests that tandem duplication events contributed to the expansion of the NlYellow gene family. NlYellow-b exhibited the highest transcript levels among all identified NlYellow genes, particularly in the female ovipositor, and functional characterization via RNAi revealed that it is essential for molting, wing development, and female fertility. Knockdown of NlYellow-b in fourth-instar nymphs caused lethal molting defects and wing malformation and significantly reduced offspring production. These findings highlight the dual roles of NlYellow-b in development and reproduction, advance our understanding of yellow gene function in insects and highlight NlYellow-b as a candidate for RNAi-based management of N. lugens. Full article

Heat shock protein 70 (HSP70) regulates the stress tolerance and reproductive ability of insects. In this study, the SfHSP70-7 gene was cloned and identified from the rice pest Sogatella furcifera. SfHSP70-7 encodes a typical cytoplasmic HSP70 protein that has a conserved functional domain and is highly similar to the HSP70 homologous protein of Laodelphax striatellus. SfHSP70-7 was found to be widely expressed across all developmental stages, with the highest levels in nymphs and female adults. In terms of tissue distribution, it was particularly abundant in the gut and ovaries. Its expression was strongly induced by high/low temperatures and three insecticides (triflumezopyrim, sulfoxaflor, and imidacloprid), with the maximum induction under heat and triflumezopyrim stress. RNA interference (RNAi) efficiently silenced SfHSP70-7 and significantly increased the susceptibility of S. furcifera to triflumezopyrim and sulfoxaflor, but it had no effect on susceptibility to imidacloprid. RNAi knockdown of SfHSP70-7 markedly reduced survival by 45.5% (30 °C) and 38.9% (35 °C) under heat stress. In addition, gene knockdown can damage the reproductive performance of females by reducing oviposition and egg hatchability. These results indicate that SfHSP70-7 is involved in regulating the heat tolerance, insecticide adaptability, and reproductive regulation mechanism of S. furcifera, providing a potential target for pest control. Full article

Root nitrogen acquisition is a central belowground process that determines how efficiently plants capture nitrogen from the rhizosphere and influences fertilizer demand and environmental nitrogen losses. Root N transporters, including nitrate, ammonium, amino acid, and peptide transporters, provide the molecular basis for inorganic and organic N uptake. However, root N acquisition is not determined solely by plant transport systems but is also shaped by rhizosphere microbial communities that regulate N mobilization, transformation, and availability. In addition to bacteria and archaea, saprotrophic fungi and mycorrhizal associations contribute to organic matter decomposition, N mineralization, and symbiotic N transfer. Mechanistically, transporter activity may alter rhizosphere N gradients and substrate availability, while root exudates and microbial metabolites can influence microbial recruitment, root physiology, and transporter expression. Evidence from rice NRT1.1B and OsLHT1 suggests that specific N transporter genes can influence rhizosphere microbiome assembly, although direct genetic evidence remains limited to a small number of transporter systems and crop contexts. This review synthesizes current knowledge on root N transporter diversity, rhizosphere microbial N cycling, organic N availability, and transporter–microbiome feedbacks in root-level N acquisition. By integrating plant physiology, soil microbiology, and rhizosphere ecology, this review proposes a conceptual framework in which root N transporters and microbial communities act as interconnected components of belowground N acquisition. Future integration of transporter-informed breeding, microbiome management, and fertilization strategies may improve root N capture while reducing reliance on synthetic N inputs. Full article

Anther length is a crucial agronomic trait that directly correlates with pollen number and pollination efficiency, thereby affecting rice grain yield and hybrid seed production. However, the specific molecular mechanisms regulating rice anther length remain largely unclear. In this study, we identified a short anther (san) mutant generated by CRISPR/Cas9, which exhibited significantly shortened anthers and reduced pollen number, without affecting other agronomic traits or pollen viability. Cytological observations revealed that the shortened anther phenotype in san mutants was caused by reduced epidermal cell number, rather than altered cell size. SAN was highly expressed in spikelets and developing anthers and encodes a nucleus-localized C1-1iG subclass C₂H₂ zinc finger protein with a conserved QALGGH motif and a C-terminal EAR motif. Further assays demonstrated that SAN functions as a transcriptional repressor, and could interact with the corepressor TPR2 in the nucleus. RNA-seq analysis indicated that SAN influences expression of genes associated with cell cycle and cytokinin, which are critical for epidermal cell division during anther development. Phylogenetic analysis showed that SAN was evolutionarily conserved in plants and was closely related to Arabidopsis SUP/ZFP11 and rice SRO. Collectively, our findings revealed that SAN specifically modulated rice anther length by promoting epidermal cell division and providing new insights into the molecular mechanism of anther size regulation. Full article

Common wild rice (Oryza rufipogon Griff.) is an important germplasm resource harboring valuable genes. Our previous analysis identified a core collection of wild rice primarily originating from the common wild rice of Guangdong Province. However, there was no information on its salt-stress tolerance. In this study, we assessed 13 accessions of common wild rice collected in Gaozhou, Guangdong, China. Salt-stress treatments applied at the tillering and seedling stages revealed that CRW3 exhibited stronger salt tolerance than CRW13 under NaCl treatment. Cytological observations indicated that root tip elongation in CRW3 was less inhibited by NaCl treatment, accompanied by a lower percentage of abnormalities in cortical cells and layers, as well as reduced shrinkage of epidermal cells. Resequencing analysis identified 2390 genes with genetic variations between CRW3 and CRW13. Furthermore, RT-qPCR was conducted to examine the expression levels of salt-stress-related genes in these two accessions. Overall, our study demonstrates the strong salt tolerance of CRW3, providing a theoretical foundation for the selection of salt-tolerant germplasm in rice. Full article

A polysaccharide with water solubility named RRBP was extracted from red rice bran (Oryza sativa L.), and its structural characterization was analyzed. The polysaccharide exhibited a monodisperse molecular weight distribution with an average of 51.4 kDa, and also comprised glucose (98.1%, w/w) and small amounts of arabinose, galactose, xylose, and mannose. Structural investigations using methylation analysis combined with UV and FT-IR spectroscopy demonstrated that RRBP is a structurally complex hyperbranched glucan characterized by an extensive branch with “→4)-α-d-Glcp-(1“→linkages constituting 30.6% of the backbone. RRBP demonstrated concentration-dependent stimulation of nitric oxide (NO) generation along with elevated secretion levels of IL-6 and TNF-α but showed minimal effect on IL-12 production in assays with RAW264.7 macrophage cells. Gene expression profiling verified the enhanced transcription of genes encoding iNOS and pro-inflammatory cytokines including IL-6, TNF-α, and IL-12 following RRBP treatment. Moreover, it is important to note that RRBP was able to promote M1 macrophage activation and exhibited no cytotoxicity, and this implied that RRBP could serve as a biocompatible pro-inflammatory immunostimulant. In summary, these findings suggested that RRBP is a distinctive glucan that possesses selective immunomodulatory properties and could be applied in the development of functional food products designed for targeted immune system modulation. Full article

Background/Objectives: Both NPs and Cd alone exert adverse effects on plant growth by disrupting physiological processes and gene expression. However, the mechanisms underlying their combined effects on plant genetic responses remain incompletely understood. Methods: The rice seedlings were used as the experimental material, with the following six treatments established: CK (Control, no NPs and Cd), 10 and 100 mg·L⁻¹ NPs, and 0.5 mg·L⁻¹ Cd alone and combination. Seedlings at the three-leaf stage were treated in hydroponic culture for 7 days, after which root-development parameters, root viability, MDA and soluble sugar contents, and SOD and POD activities were measured, along with transcriptomic analysis. Results: The results show that root length, number of root tips, and root surface area were highest in CK compared with all NPs and Cd treatments, particularly. Significant differences were observed between the CK and both the high-concentration NPs and all Cd treatments groups (p < 0.05). Root growth progressively declined with increasing NP concentrations; the combination of 100 mg·L⁻¹ NPs and 0.5 mg·L⁻¹ Cd exhibited synergistic toxicity, which decreased root length, number of root tips, and root surface area by 14%, 22%, and 4% compared with 0.5 Cd, whereas 10 mg·L⁻¹ NPs significantly alleviated Cd-induced root damage for the three root parameters above in the following order: 0.5 Cd < 0.5 Cd-10 NPs < 10 NPs. In terms of physiological changes, 10 mg·L⁻¹ NPs reduced MDA levels and enhanced SOD and POD activities in roots exposed to Cd; in contrast, 100 mg·L⁻¹ NPs exacerbated Cd-induced membrane peroxidation and decreased SOD and POD activities. In the high-concentration NPs and all Cd-treated groups, all aforementioned indicators exhibited significant differences compared with the CK (p < 0.05). Transcriptomic and WGCNA analyses revealed that the expression levels of OsGRP162 (regulating resistance) and OsCYP2 (inhibiting lateral root formation under overexpression) were significantly higher in 0.5 Cd-100 NPs compared with the other five treatments, while OsTubA2 (positively regulating root length) exhibited a different pattern. Differentially expressed genes (DEGs) in experimental groups of 10 NPS_vs_0.5 Cd-10 NPS and 100 NPS_vs_0.5 Cd-100 NPS were predominantly enriched in glutathione metabolism and the MAPK signaling pathway, respectively. The key genes OsMT4C, OsMT4B and OsYSL2 (associated with transmembrane signal transduction), and OsABCB5 and OsCUL1-3 (involved in negative regulation of root elongation) exhibited reduced expression levels in 0.5 Cd-10 NPs, whereas OsYDA2 and OsAGO1c (related to antioxidant defense) showed upregulated expression. Conversely, the opposite gene expression patterns were observed in 0.5 Cd-100 NPs. Conclusions: These findings demonstrate that both NPs and Cd adversely affect rice seedlings; however, low concentrations of NPs mitigate Cd toxicity, while high concentrations exacerbate it. Therefore, to prevent elevated NP concentrations in plant growth environments, plastic usage and processing should be standardized. Full article

Low temperature is an abiotic stress factor that affects plant development and geographic expansion, resulting in significant economic losses in worldwide food production each year. Through evolution, plants have developed intricate adaptation systems, with epigenetic regulation—modifying gene expression without altering DNA sequences—being pivotal in the cold stress response and memory formation. This review provides a systematic overview of the role of the main epigenetic mechanisms, including histone modifications, DNA methylation, non-coding RNA regulation, and chromatin remodeling, in plant cold stress responses. The article summarized research on plants, including model species Arabidopsis thaliana and rice, examined epigenetically mediated cold-stress memory and transgenerational epigenetic inheritance, and analyzed synergistic interactions among regulatory pathways. Finally, by integrating recent advances, the study identifies scientific challenges and research bottlenecks in this field and outlines future research directions and application prospects in cold-resistant crop breeding. Finally, by integrating recent advances, the study identifies scientific challenges and research bottlenecks in this field, outlines future research directions and application prospects for cold-resistant crop breeding, and provides references for further elucidating the molecular mechanisms of plant cold adaptation and for developing new cold-resistant crop varieties. These outcomes offer references for further elucidating the molecular mechanisms of plant cold adaptation and developing new cold-resistant crop varieties. Full article

Japonica soft rice varieties possess excellent eating quality, and their cultivation area has been steadily expanding in recent years. This study aimed to analyze japonica soft rice varieties cultivated in the Yangtze River Delta region of China at the genome level and to provide a theoretical basis for optimizing disease resistance and other important traits. Genotypic characterization and evaluation of ten major japonica soft rice varieties from the Yangtze River Delta region were conducted using a genome-wide single nucleotide polymorphism (SNP) chip. The experimental results indicated that the soft rice varieties in the Yangtze River Delta region had a relatively high japonica component and were all classified as typical japonica rice varieties. Specifically, the highest (95.6%) and lowest (91.5%) proportions of japonica genomic segments were detected in Tai’an 1 and Zhehexiang 2, respectively. Japonica soft rice varieties from Shanghai exhibited a closer genetic distance to those from Jiangsu Province than to those from Zhejiang Province. Genomic identity was highest between Tai’an 1 and Nanjing 46 (87.9%) and lowest between Tai’an 1 and Jia 67 (74.4%). Based on the results of the chip assay, a total of twenty-six functional genes controlling key traits, such as yield, quality, and resistance to biotic and abiotic stresses, were identified in the ten analyzed varieties. Among them, Zhehexiang 2 carried the broad-spectrum blast resistance genes Pi2 and Pita, which is useful for improving the blast resistance of japonica soft rice varieties. The findings of this study provide genetic resources and carrier materials for the efficient molecular improvement of japonica soft rice varieties. Full article

Lactic acid bacteria (LAB)-mediated fermentation has been widely explored as a strategy to enhance the nutritional functionality of cereal processing by-products. In this study, 50 LAB strains previously isolated from Korean traditional fermented foods and obtained from the National Agrobiodiversity Center (KACC, Jeonju-si, Republic of Korea) were systematically screened for bifunctional carbohydrate and protein degradation capacities, and their potential to improve the nutritional functionality of wheat bran was evaluated. Paper disc assays revealed substantial inter-strain variability, with clear zone diameters ranging from 12.35 to 29.52 mm for carbohydrate degradation and 11.61 to 25.45 mm for protein degradation. Ten strains exceeding both upper-quartile enzymatic degradation cutoff thresholds (≥25.25 mm for carbohydrate degradation and ≥17.98 mm for protein degradation, respectively) were putatively identified as Lactiplantibacillus plantarum and Lacticaseibacillus paracasei based on 16S rRNA gene sequencing (99.73–100% similarity). Substrate-specific fermentation using L. paracasei KS 595 across four substrates (brewed soy sauce soybean meal, pea, floury rice, and wheat bran) demonstrated substrate-dependent differences in growth and branched-chain amino acid (BCAA) accumulation, with the highest increase observed in pea fermentation. Strain-specific evaluation during wheat bran fermentation revealed distinct differences in growth kinetics, pH reduction, and BCAA production driven by cell-envelope proteinases and intracellular peptidases, with viable cell counts reaching 9–10 log CFU/mL after 48 h. Biogenic amine analysis indicated that histamine levels remained below commonly accepted safety limits in all strains, while L. paracasei KS 543 showed no detectable tyramine or histamine. Although the potential improvement in plant protein bioavailability was indirectly inferred through the free BCAA enrichment rather than directly measured in vivo, these results support a systematic screening approach for selecting LAB strains capable of producing BCAA-enriched fermented wheat bran, with potential implications for improving plant protein bioavailability and addressing nutritional needs in aging and active populations. Full article

Pyruvate kinase (PK) is the terminal rate-limiting enzyme of glycolysis and occupies a central position in plant energy metabolism and carbon skeleton allocation. Plant PK isoenzymes comprise the cytosolic pyruvate kinase (PKc) and the plastidic pyruvate kinase (PKp), which differ markedly in gene origin, protein structure, subcellular localization, and physiological function, exhibiting independent evolutionary histories and functional diversification. Recent studies have revealed that PKc possesses dynamic subcellular distribution, allowing it to shuttle among the cytosol, mitochondria, and nucleus, where it participates in stress responses and epigenetic regulation through protein–protein interactions. PKp is localized to plastids and connects carbon metabolism with lipid biosynthesis and the methylerythritol phosphate (MEP) pathway by supplying pyruvate, thereby playing critical roles in seed development and oil accumulation. This review comprehensively summarizes recent advances in plant PKc and PKp concerning protein structure and subunit composition, tissue-specific expression, subcellular localization, protein interaction networks, activity regulation, and their effects on plant growth, development, and stress responses. In addition, phylogenetic tree, motif, and domain analyses of pyruvate kinase genes from Oryza sativa (rice), Glycine max (soybean), Gossypium hirsutum (cotton), Solanum tuberosum (potato), Arachis hypogaea (peanut), and Arabidopsis thaliana, as well as promoter cis-element analyses, are performed. This review aims to provide theoretical references for crop quality improvement and stress-resilient breeding. Full article

Rice tiller number is a key determinant of panicle number and yield, yet its genetic architecture is highly influenced by environmental variation. Identifying loci showing reproducible effects across multiple growing seasons at the same experimental site is important for improving the reliability of GWAS-based locus prioritization for breeding. In this study, 240 rice accessions from the Rice3K panel were evaluated for tiller number over three growing seasons (2021–2023) in Sanya, Hainan Province, representing the South China rice-growing region. Genome-wide association analyses using GLM and MLM, combined with BLUEs, identified reproducible genetic signals. Several previously reported tillering-related genes, such as NAL1, BON3, ANT1, MRG702, D27, WTG1, and VPE2, were detected across different analyses. Among them, NAL1 and ANT1 represented the most consistently associated loci across three growing seasons and statistical models. Gene-based association analysis identified the promoter variants Chr4:31203262 (C/T) in NAL1 and Chr7:7310528 (G/A) in ANT1 as the lead polymorphisms, with the favorable C and G alleles associated with increased tiller number, respectively. In addition, nine putative candidate loci showing suggestive associations across three growing seasons were identified as putative candidate breeding resources. These results highlight the importance of integrating multi-year phenotyping with GWAS to prioritize loci showing reproducible associations across three growing seasons and provide valuable candidate genetic resources for future molecular improvement of rice adapted to the South China rice-growing region. Full article

Methylmercury (MeHg) accumulation in rice is a major source of human MeHg exposure in some inland areas, yet the mechanism controlling mercury (Hg) accumulation in high geological background (HGB) regions remains poorly understood. Here, a field-scale remediation experiment was conducted in a karst HGB region of Guizhou, China, using a synergistic strategy combining selenium foliar spraying and calcium oxide-based soil conditioner. The combined treatment reduced total Hg and MeHg concentrations in rice grains by 63.0% and 80.0%, respectively. The root uptake from the soil–water system was found to be the primary pathway controlling Hg transfer into rice grain. Mechanistically, the soil conditioner increased soil pH and reduced bioavailable Hg, porewater Hg, and soil MeHg by 53.6%, 59.8%, and 62.6%, respectively, whereas selenium foliar spraying promoted Hg–Se complexation and reduced Hg mobility in the paddy system. In parallel, the combined treatment suppressed Hg-methylating microorganism (e.g., Geobacter decreased by 65%) and hgcAB gene (hgcA: −65%; hgcB: −58%), while enriching Hg-resistant taxa and merA-mediated detoxification pathway. These coupled physicochemical and microbial processes substantially reduced Hg bioavailability, MeHg production, and Hg bioaccumulation in rice grain of the paddy ecosystem, providing an effective strategy for mitigating Hg-related food safety risk in the karst HGB region. Full article