Search Results (1,254)

Synergizing iron nutrition and rice quality is essential for the development of integrated high-quality rice. In this study, a two-year field experiment was conducted to investigate the influence of ferric oxide nanoparticles (Fe₂O₃ NPs) foliar spraying on rice yield, quality, and iron bioavailability, with spraying water as the control (CK). Our results demonstrate that Fe₂O₃ NPs foliar application increase grain yield by 1.22–3.97% for the improved filled grain rate and 1000-grain weight, essentially attributed to improved net photosynthetic rate and SPAD value after heading. In addition, Fe₂O₃ NPs application achieved a higher rate of brown rice, polished rice, and head rice, and decreased chalkiness grain rate and chalkiness degree. Rice taste value treated with Fe₂O₃ NPs application was notably increased by 2.75–9.43% compared to CK, respectively, which is also reflected in the superior breakdown value (5.85–15.18%) and inferior setback value (12.38–28.19%). Meanwhile, foliar spraying Fe₂O₃ NPs significantly increased the iron content (16.97–58.74% and 26.48–94.01%) and proportion (2.90–5.35% and 13.10–26.44%), while they decreased the molar ratio of phytate to Fe (19.70–33.67% and 31.55–45.77%) in brown rice and polished rice, increasing iron bioavailability. Our findings indicate that Fe₂O₃ NPs can be effectively applied as a foliar fertilizer to enhance rice yield, quality, and iron nutrition. Full article

Leaf senescence is the final stage of plant leaf development, closely related to the yield and quality of cereal crops. However, the molecular regulatory mechanism of rice (Oryza sativa L.) leaf senescence is not yet very clear. This study conducted weighted gene co-expression network analysis (WGCNA) using two independent senescence-related transcriptome datasets of rice. Modules positively/negatively correlated with leaf senescence were obtained for each dataset. The additional intersection analysis screened out 180 and 248 common genes highly and positively/negatively correlated with leaf senescence. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses showed that these identified common genes were mainly enriched in senescence-related biological processes and pathways, such as reactive oxygen metabolism, hormone pathway, cell death regulation, stimulus–response, amino acid metabolism, photosynthetic metabolism, etc. Transcription factors and studied genes were identified from these common genes, finding that transcription regulation, hormone regulation, reactive oxygen species metabolism, and photosynthesis pathways play an essential role in rice leaf senescence. Protein–protein interaction (PPI) network analysis identified 28 key genes probably involved in leaf senescence. Hub network analysis identified 68 hub genes probably participating in leaf senescence. Twelve genes from the PPI network and the hub gene network were selected for RT-qPCR validation of their expression patterns during leaf senescence. The functions of the senescence-correlated genes identified in this study are discussed in detail. These results provide valuable insights into the regulatory mechanisms of leaf senescence in rice and lay a foundation for functional research on candidate senescence genes. Full article

As a staple food crop, Oryza sativa L. is not only the basis of global food and nutrition security but also an important cornerstone of national economic development and social stability. However, the growth of rice is often accompanied by the threat of rice blast, which can lead to the death of seedlings or plants before heading. In the later stages of growth, a severe leaf blast infection will reduce the leaf area at the filling stage, thereby reducing the grain yield. The study of rice blast resistance genes and susceptibility genes is a key strategy for controlling the occurrence of rice blast and ensuring sustainable rice production. This paper reviews the impact of rice blast on the global economy and food security in recent years, describes the immune mechanism of rice blast resistance, and introduces the latest progress in related research. At the same time, the main genes of rice blast resistance and the resistance-related genes, as well as the susceptibility genes identified or cloned in recent years, are summarized. This paper also discusses the application of conventional breeding, molecular-marker-assisted breeding, gene editing, and other technologies in rice blast resistance breeding. The problem of accurately finding avirulence genes for R genes in current disease-resistant breeding is discussed and explored, aiming to improve rice blast resistance, agronomic traits, and yield in a sustainable way. Full article

The growth of rice (Oryza sativa L.) is affected by long days, which occur throughout the year in southern China, leading to a sharp decline in rice varieties and yields. In order to conduct adaptive genetic breeding research on rice, it is urgent to understand the long days response mechanism of rice. This study used RNA-seq technology to analyze rice under long day conditions and found that RNA, Ehd1, chlorophyll a/b binding protein, were identified as key genes or proteins under long day conditions. MAPK is closely related to long day conditions. This study provides a unique theoretical basis for long-term research and genetic breeding of rice by screening key genes related to the photoperiod. Full article

Chlorophyll biosynthesis is essential for photosynthesis and plant development. Disruptions in this pathway often manifest as pigment-deficient phenotypes. This study characterizes the morphological, anatomical, and physiological consequences of a chlorophyll-deficient rice mutant (yellow seedling, YS) caused by a loss-of-function mutation in the OsCHLI gene, which encodes the ATPase subunit of magnesium chelatase. Comparative analyses between YSs and wild-type green seedlings (GSs) revealed that YSs exhibited severe growth retardation, altered mesophyll structure, reduced xylem and bulliform cell areas, and higher stomatal and papillae density. These phenotypes were strongly light-dependent, indicating that OsCHLI plays a crucial role in light-mediated chloroplast development and growth. Transcriptome analysis further revealed global down-regulation of photosynthesis-, TCA cycle-, and cell wall-related genes, alongside selective up-regulation of redox-related pathways. These results suggest that chlorophyll deficiency induces systemic metabolic reprogramming, prioritizing stress responses over growth. This study highlights the multifaceted role of OsCHLI in plastid maturation, retrograde signaling, and developmental regulation, providing new insights for improving photosynthetic efficiency and stress resilience in rice. Full article

Bacterial cell morphology might result from natural selection to gain a competitive advantage under environmentally stressful conditions such as nutrient limitation. In nutrient-limited conditions, a higher surface-to-volume ratio is crucial for cell survival because it allows for a more efficient exchange of nutrients and waste products. A bacterial strain YC6860^T isolated from the rhizosphere of rice (Oryza sativa L.) showed pleomorphic behavior with smooth cell morphology and wrinkled surface rods depending upon nutritional conditions. Based on scanning and transmission electron microscopy studies, we hypothesized that the surface-to-volume ratio of cells would increase with decreasing nutrient concentrations and tested this quantitatively. The transition from smooth to wrinkled cell surface morphology could be one of the adaptation strategies by which YC6860^T maximizes its ability to access available nutrients. To characterize the properties of the wrinkled strain, we performed taxonomic and phylogenetic analyses. 16S rRNA gene sequencing results showed that the strain represented a novel, deep-rooting lineage within the order Rhizobiales with the highest similarity of 94.2% to Pseudorhodoplanes sinuspersici RIPI 110^T. Whole-genome sequencing was also performed to characterize its genetic features. The low phylogenetic and genetic similarity is probably related to the wrinkled morphology of the strain. Therefore, we propose that the strain YC6860^T might belong to a new genus and species, named Rugositalea oryzae. In addition, taxonomic analysis showed that YC6860^T is Gram-negative, aerobic, and rod-shaped with regular surface wrinkles under nutrient-limiting conditions, resembling a delicate twist of fusilli, with groove depths of 48.8 ± 3.7 nm and spacing of 122.5 ± 16.9 nm. This unique cell structure with regular rugosity could be the first finding that has not been reported in the existing bacterial morphology. Full article

Agrobacterium-mediated transformation systems are extensively applied in japonica rice varieties. However, the adaptability of local rice varieties to existing transformation systems remains limited, owing to their complex genotypes, posing a substantial challenge to transformation. In this study, four local rice varieties were selected to optimize the effects of different culture media on callus induction, browning resistance, contamination resistance, callus tolerance, differentiation, regeneration, and root development, and then two varieties were selected to improve plant architecture and tiller development by CRISPR/Cas9-mediated gene editing, based on constructive transformation systems. The goal was to enhance the transformation efficiency of local varieties and innovate germplasms. The results demonstrated that japonica rice varieties XG293 and WD68 exhibited higher induction rates under the treatment of 2 mg/L 2,4-D (2,4-Dichlorophenoxyacetic acid) + 1 mg/L NAA (Naphthaleneacetic acid), whereas indica rice varieties H128 and E33 performed the best under 3 mg/L 2,4-D + 1 mg/L NAA. Severe browning in H128 was effectively mitigated by a carbon source of 20 g/L maltose supplemented with 40 mg/L ascorbic acid. Contamination after Agrobacterium infection was controlled by 300 mg/L Tmt (Timentin). Under a treatment of 200 µM/L acetosyringone +10 min infection duration, XG293 and WD68 exhibited higher callus tolerance, differentiation rates, and GUS staining rates, achieving transformation efficiencies of 43.24% and 52.38%, respectively. In contrast, H128 and E33 performed better under the treatment of 200 µM/L Acetosyringone + 5 min, with transformation efficiencies of 40.00% and 40.74%, respectively. The mutants after OsCCD7 gene editing in WD68 and H128 displayed a dwarfness of plant height, a significant increase in tiller numbers, and compact architecture. These findings demonstrate that an optimized combination of plant growth regulators and infection durations effectively improves transformation efficiency for local varieties, and the OsCCD7 gene regulates plant architecture and tiller development with variable effects, depending on the rice complex genotypes. This study provides a theoretical basis for the efficient transformation of local rice varieties and germplasm innovation. Full article

Seedling cultivation of rice (Oryza sativa L.) is a critical initial step in rice production. This study investigated the effects of sowing methods and strigolactone (GR24) on rice seedlings under salt stress. Results showed that drill-sown seedlings exhibited superior quality under normal conditions compared to broadcast-sown seedlings. Salt stress significantly increased the contents of Cl⁻, Na⁺, reactive oxygen species (ROS), and malondialdehyde (MDA), disrupted chloroplast structure and hormonal balance, and reduced gas exchange parameters and chlorophyll fluorescence parameters. Notably, drill-sowing conferred stronger salt tolerance than broadcast-sowing. Exogenous application of GR24 enhanced activities of antioxidant enzymes—including superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD), and catalase (CAT)—and elevated non-enzymatic antioxidant contents such as ascorbic acid (ASA), glutathione (GSH), total phenolics, and flavonoids, alongside related enzyme activities. Concurrently, GR24 reduced Na⁺ and Cl⁻ accumulation, lowered the Na⁺/K⁺ ratio, and increased the contents of K⁺, Ca²⁺, Mg²⁺, and hormones. Consequently, GR24 decreased MDA and ROS levels, protected membrane integrity, reduced electrolyte leakage, repaired chloroplast structure, and improved gas exchange and chlorophyll fluorescence parameters. Due to their superior spatial distribution and photosynthetic efficiency, drill-sown seedlings synergized with GR24 to enhance antioxidant capacity under salt stress, enabling more effective scavenging of peroxidative radicals, stabilization of the photosynthetic system, and mitigation of salt-induced growth inhibition. Ultimately, this combination demonstrated greater stress alleviation than broadcast-sown seedlings. Full article

Rice blast is one of the main diseases of rice, causing severe economic losses to agricultural production; thus, the search for blast resistance is a top priority for rice breeding. When challenged by the blast causal fungus Magnaporthe oryzae the expression level of OsMAPKKK69 gene in rice cultivar Nipponbar was found to increase significantly. Such an induction was also found in a different genetic material, cultivar Shufanggaonuo, indicating that OsMAPKKK69 plays an important role in blast disease response. However, the function of OsMAPKKK69 remains unclear. In this study, wild type ZH11 was selected as the background material to investigate the expression and functions of OsMAPKKK69 in rice disease resistance by constructing knockout mutants. The results showed that OsMAPKKK69 is mainly expressed in four-week-old shoots and localized in cell membrane, cytoplasm, and nucleus. The two allelic knockout mutants, osmapkkk69-1 and osmapkkk69-2, were more resistant to M. oryzae and bacterial blight Xanthomonas oryzae pv. Oryzae (Xoo). Further agronomic trait analysis revealed that the osmapkkk69-1 and osmapkkk69-2 mutants had reduced plant height, smaller grain size, a significant increase in tillering number, but also a significant increase in yield per plant. Our results show that OsMAPKKK69 is involved in the immune response of rice by negatively regulating the resistance to rice blast and blight diseases, and in regulating important agronomic traits. This study lays a foundation for revealing the molecular mechanism of OsMAPKKK69 in the immune response to rice diseases and provides novel genetic resources for rice breeding. Full article

Lycium barbarum is a traditional medicinal and edible plant species in China, exhibiting notable salt tolerance that enables cultivation in salt-affected soils. However, intensifying soil salinization has rendered severe salt stress a critical limiting factor for its fruit yield and quality. Universal stress proteins (USPs) serve as crucial regulators for plant abiotic stress responses through developmental process modulation. Nevertheless, the characteristics and functional divergence of USP gene family members remain unexplored in L. barbarum. Here, we performed genome-wide identification and characterization of the USP gene family in L. barbarum, revealing 52 members unevenly distributed across all 12 chromosomes. Phylogenetic analysis classified these LbUSP members into four distinct groups, demonstrating the integration of the conserved USP domain and diverse motifs within each group. Collinearity analysis indicated a stronger synteny of LbUSPs with orthologs in Solanum lycopersicum than with other species (Arabidopsis thaliana, Vitis vinifera, and Oryza sativa), demonstrating that gene duplication coupled with functional conservation represented the primary mechanism underlying USP family expansion in L. barbarum. In silico promoter screening detected abundant cis-acting elements associated with abiotic/biotic stress responses (MYB and MYC binding sites), phytohormone regulation (ABRE motif), and growth/development processes (Box-4 and G-box). Transcriptome sequencing and RT-qPCR validation revealed tissue-specific differential expression patterns of LbUSP8, LbUSP11, LbUSP12, LbUSP23, and LbUSP25 in roots and stems under salt stress, identifying them as prime candidates for mediating salt resistance in L. barbarum. Our findings establish a foundation for the functional characterization of LbUSPs and molecular breeding of salt-tolerant L. barbarum cultivars. Full article

Leaf morphology significantly impacts rice (Oryza sativa L.) plant architecture and yield. Here, we identified and characterized a novel narrow-leaf mutant, nal25, derived from indica rice cultivar ‘Huazhan’ using EMS mutagenesis. Phenotypic analyses revealed that nal25 exhibited significantly narrower leaves, reduced plant height, increased tiller number, and notably decreased grain size, seed setting rate, and thousand-grain weight compared to the wild type. Genetic analyses demonstrated that the narrow-leaf phenotype is controlled by a single recessive nuclear gene. Through precise localization analysis, the NAL25 gene was located within a region of approximately 103 kb on the long arm of rice chromosome 7. The sequencing results showed that the mutant nal25 had a T to C mutation at position 173 of the heat-shock protein gene LOC_Os07g09450 encoding the DnaJ domain in this interval, resulting in a change in amino acid 58 from leucine to proline. The qRT-PCR results showed that the expression level of NAL25 gene decreased in the mutant. The nal25 mutant obtained in this study exhibits stable mutant phenotypes, including dwarfism and excessive tillering, traits typically unfavorable for rice production. Nevertheless, it serves as valuable genetic material for forward genetics approaches to identify yield-related genes regulating leaf morphology and culm height. Thus, research on the nal25 mutant advances the development of rice varieties with ideal plant architecture, thereby stabilizing yield increases and safeguarding global food security. Full article

Rice (Oryza sativa L.) is a staple crop for over half of the global population; however, pathogenic infections pose significant threats to its sustainable production. Although chemical pesticides are commonly employed for disease control, their prolonged usage has led to pathogen resistance, reduced effectiveness, and non-target toxicity, rendering them unsustainable for agricultural practices. Nanomaterials (NMs) present a promising alternative due to their small size, tunable release properties, and diverse mechanisms for disease resistance. This review examines how NMs can enhance rice disease management through (1) direct pathogen suppression; (2) the activation of plant defense pathways; (3) the formation of nanoscale barriers on leaves to obstruct pathogens; (4) targeted delivery and controlled release of fungicides; and (5) modulation of the microbiome to bolster resilience. Moreover, we critically analyze the agricultural potential and environmental implications of NMs, develop optimized application strategies, and, for the first time, propose the innovative ‘NMs-Rice-Soil’ Ternary System framework. This groundbreaking approach integrates nanotechnology, plant physiology, and soil ecology. The pioneering framework offers transformative solutions for sustainable crop protection, illustrating how strategically engineered NMs can synergistically enhance rice productivity, grain quality, and global food security through science-based risk management and interdisciplinary innovation. Full article

Rice (Oryza sativa L.) plays a pivotal role in the Brazilian economy, serving as a staple food for more than half of the world’s population and thereby contributing to global food security. Projections of future climate change scenarios indicate an increase in extreme weather events. Among climate variables that impact the development and productivity of irrigated rice, solar radiation is one of the most important in defining productive potential. Understanding the risks imposed on agricultural production by the occurrence of days with reduced luminosity availability is crucial for guiding adequate responses that mitigate the negative impacts of climate variability. Therefore, this study aimed to investigate the effect of shade on the metabolism and productivity of irrigated rice plants, with a specific focus on the synthesis of photosynthetic pigments, carbohydrate accumulation, invertase activity, and the nutritional status and grain yield of rice. For this, the study was conducted on the field rice cultivars IRGA 424 RI, BRS PAMPA, and BRS PAMPEIRA, which were subjected to 35% shading using black nylon netting installed when the plants reached the reproductive stage (R0). The restriction was maintained until the R4 stage, and later, from the R4 stage until the R9 stage. After the imposition of treatments, evaluations took place at the phenological stages R2, R4, R6, and R8. In shaded plants, a higher content of photosynthetic pigments and a lower accumulation of carbohydrates were observed, which was reflected in an increase in the activity of invertase enzymes. These conditions were able to potentiate effects on the nutritional status of the plants, in addition to reducing productivity and 1000-grain weight and increasing spikelet sterility, due to changes in the source–sink relationship, with effects more pronounced in cultivars BRS PAMPA and BRS PAMPEIRA during the R4–R9 period. Full article

The Cupin superfamily, characterized by a conserved β-barrel structure, plays crucial roles in plant growth, development, and stress responses. However, comprehensive analyses of this gene family in rice remains limited. Here, we performed a genome-wide identification, molecular evolution, and expression analysis of Cupin genes in rice under abiotic stress. Utilizing the telomere-to-telomere (T2T) genome of rice, 54 Cupin genes (OsCupins) were identified and classified into four subfamilies (GLP, PIRIN, TRR14, and ARD) based on phylogenetic relationships with Arabidopsis homologs. These genes were unevenly distributed across ten chromosomes, with tandem and segmental duplications driving their expansion. Structural and synteny analyses revealed conserved motifs and orthologous relationships with sorghum and Arabidopsis. The promoter regions of OsCupins were enriched in stress-responsive cis-elements, including ABRE, MYB, and MYC motifs. qRT-PCR data demonstrated the significant upregulation of multiple OsCupins (e.g., OsGLP15, OsGLP38, and OsGLP43) under NaCl and PEG 6000 treatments. Functional validation in yeast showed that the overexpression of OsGLP15, OsGLP38, or OsGLP43 enhanced salt and drought tolerance in yeast, with OsGLP43 exhibiting the strongest stress resilience. Our findings provide insights into the evolutionary dynamics and stress-responsive regulatory mechanisms of the Cupin superfamily in rice, offering potential targets for enhancing abiotic stress tolerance in this critical crop. Full article

In addition to being governed by genetic factors, environmental factors also play a crucial role in influencing the fragrance of rice. In this research, the high-quality rice variety Dalixiang was selected as the experimental material to investigate the impacts of soil nutrients in Guiyang and Meitan on its fragrance. The results indicated that the levels of ammonium nitrogen, organic matter, total nitrogen, available nitrogen, and the pH value in the soil of Meitan were lower compared to those in Guiyang. Conversely, the contents of total potassium, available phosphorus, and available potassium were higher in Meitan. Specifically, the concentrations of 2-acetyl-1-pyrroline (2AP) in the leaves of Dalixiang at the heading stage and in the grains at the maturity stage at the Meitan planting site were 0.13 mg/kg and 0.56 mg/kg, respectively. These values were significantly lower than the 0.17 mg/kg and 0.64 mg/kg measured at the Guiyang planting site. This phenomenon is associated with the higher expression levels of the betaine aldehyde dehydrogenase (OsBadh2) gene, enhanced enzyme activities, and a greater content of γ-aminobutyric acid (GABA) in the leaves of Dalixiang at the Meitan planting site. In contrast, the expression levels of genes related to triose phosphate isomerase (OsTPI), proline dehydrogenase (OsProDH), ornithine aminotransferase (OsOAT), and Delta1-pyrroline-5-carboxylic acid synthetase (OsP5CS), along with their corresponding enzyme activities, as well as the contents of methylglyoxal, proline, and ornithine, were lower. In conclusion, due to the influence of the Guiyang environment, the biosynthesis of Dalixiang 2AP was promoted, which made the Dalixiang planted in Guiyang stronger than that planted in Meitan. This study provides a theoretical basis for the selection of the best planting area of Dalixiang and the improvement of Dalixiang flavor through agronomic cultivation techniques. Full article