Search Results (176)

GOLDEN2-LIKEs (GLKs) are important transcription factors for the chloroplast development influencing photosynthesis, nutrition, senescence, and stress response in plants. Sunflower (Helianthus annuus) is a highly photosynthetic plant; here, a GLK-homologues gene HaGLK was identified from the sunflower genome by bioinformatics. To analyze the bio-function of HaGLK, transgenic rice plants overexpressing HaGLK (HaGLK-OE) were constructed and characterized via phenotype. Compared to the wild-type control rice variety Zhonghua 11 (ZH11), the HaGLK-OE lines exhibited increased photosynthetic pigment contents, higher net photosynthetic rates, and enlarged chloroplast area; meanwhile, genes involved in both photosynthesis and chlorophyll biosynthesis were also significantly up-regulated. Significantly, the HaGLK-OE plants showed a 12–13% increase in yield per plant. Additionally, the HaGLK-OE plants were demonstrated to have improved salt and drought tolerance compared to the control ZH11. Our results indicated that the HaGLK gene could play multiple roles in photosynthesis and stress response in rice, underscoring its potential value for improving crop productivity and environmental adaptability in breeding. Full article

Rice is a staple food for over half of the world’s population, and it is grown in over 100 countries. Rice blast disease can cause 10% to 30% crop loss, enough to feed 60 million people. Breeding for resistance can help farmers avoid costly fungicides. This study assessed the relationship between rice blast disease and zinc or anthocyanin content in biofortified rice. Susceptibility to foliar and panicle blast was assessed in a rice panel which differed on grain zinc content and pigmentation. A rice panel (n = 23) was challenged with inoculum of two isolates of Magnaporthe oryzae in a screenhouse-based assay. The zinc content with foliar blast severity was analyzed in the leaves and grain of a subset of non-inoculated rice plants. The effect of foliar zinc supplementation on seedlings was assessed by varying levels of zinc fertilizer solution on four blast susceptible cultivars at 14 days after planting (DAP), followed by inoculation with the blast pathogen at 21 DAP. Foliar blast severity was scored on a 0–9 scale at 7 days after inoculation. The rice panel was scored for anthocyanin content, and the data were correlated with foliar blast severity. The panel was grown in the field, and panicle blast, grain yield and yield-related agronomic traits were measured. Significant differences were observed in foliar blast severity among the rice genotypes, with IRBLK-KA and IR96248-16-2-3-3-B having mean scores greater than 4, as well as BASMATI 370 (a popular aromatic variety), while the rest of the genotypes were resistant. Supplementation with foliar zinc led to a significant decrease in susceptibility. A positive correlation was observed between foliar and panicle blast. The Zn in the leaves was negatively correlated with foliar blast severity, and had a marginally positive correlation with panicle blast. There was no relationship between foliar blast severity and anthocyanin content. Grain yield had a negative correlation with panicle blast, but no correlation was observed between Zn in the grain and grain yield. This study shows that Zn biofortification in the grain may not enhance resistance to foliar and panicle blast. Furthermore, the zinc-biofortified genotypes were not agronomically superior to the contemporary rice varieties. There is a need to apply genomic selection to combine promising alleles into adapted rice genetic backgrounds. Full article

The occurrence of anthocyanins in rice (Oryza sativa) and barley (Hordeum vulgare) varies among cultivars, with pigmented varieties (e.g., black rice and purple barley) accumulating higher concentrations due to genetic and environmental factors. The biosynthesis of anthocyanins is regulated by a complex network of structural and regulatory genes. Key enzymes in the pathway include chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), anthocyanidin synthase (ANS), and UDP-glucose flavonoid 3-O-glucosyltransferase (UFGT). These genes are tightly controlled by transcription factors (TFs) from the MYB, bHLH (basic helix–loop–helix), and WD40 repeat families, which form the MBW (MYB-bHLH-WD40) regulatory complex. In rice, OsMYB transcription factors such as OsMYB3, OsC1, and OsPL (Purple Leaf) interact with OsbHLH partners (e.g., OsB1, OsB2) to activate anthocyanin biosynthesis. Similarly, in barley, HvMYB genes (e.g., HvMYB10) coordinate with HvbHLH TFs to regulate pigment accumulation. Environmental cues, such as light, temperature, and nutrient availability, further modulate these TFs, influencing the production of anthocyanin. Understanding the genetic and molecular mechanisms behind the biosynthesis of anthocyanins in rice and barley provides opportunities for the development of biofortification strategies that enhance their nutritional value. Full article

Salinity and heavy metal stress significantly reduce agricultural productivity in arable lands, particularly affecting crops like rice (Oryza sativa L.). This study aimed to evaluate the efficacy of heavy metal-tolerant plant growth-promoting rhizobacteria (HMT-PGPR) in mitigating the harmful effects of salt (NaCl), chromium (Cr), and combined NaCl + Cr stress on rice plants. Two pre-isolated and well-characterized heavy metal-tolerant epiphytic (Ochrobactrum pseudogrignonense strain P14) and endophytic (Arthrobacter woluwensis strain M1R2) PGPR were tested. The LSD test (p ≤ 0.05) was used to assess the statistical significance between treatment means. Stresses caused by NaCl, Cr, and their combination were found to impair plant growth and biomass accumulation through mechanisms, including osmotic stress, oxidative damage, ionic imbalance, reduced photosynthetic pigment, lowered relative water content, and compromised antioxidant defense systems. Conversely, inoculation with HMT-PGPR alleviated these adverse effects by reducing oxidative stress indicators, including malondialdehyde (MDA), hydrogen peroxide (H₂O₂) content and electrolyte leakage (EL) and enhancing plant growth, osmolyte synthesis, and enzymatic antioxidant activity under single- and dual-stress conditions. The application of HMT-PGPR notably restricted Na⁺ and Cr⁶⁺ uptake, with an endophytic A. woluwensis M1R2 demonstrating superior performance in reducing Cr⁶⁺ translocation (38%) and bioaccumulation (42%) in rice under dual stress. The findings suggest that A. woluwensis effectively mitigates combined salinity and chromium stress by maintaining ion homeostasis and improving the plant’s antioxidant defenses. Full article

Rich in bioactive compounds, pigmented rice offers superior antioxidant capacity compared to non-pigmented rice. Processing methods like milling, parboiling, thermal treatments (e.g., extrusion cooking), and biobased approaches (e.g., germination and fermentation) impact the technological and nutritional properties of pigmented rice. All products with added pigmented rice showed improved total phenolic content and antioxidant capacities. Extrusion cooking improved technological properties of dough, bread, and bakery products by modifying the pasting properties of rice. Germination and fermentation enhanced bakery products’ nutritional value by increasing gamma-aminobutyric acid (GABA) levels. Pigmented rice flour can enhance the volume, crumb firmness, and elasticity of gluten-free (GF) bread, especially with ohmic heating. It improved sensory qualities and consumer acceptance of various baked products and extruded snacks. While pigmented rice-based pasta and noodles had compromised cooking qualities, germination improved noodle cooking qualities. Pre-processing techniques like parboiling and micronisation show potential for improving pigmented rice’s technological properties and warrant further study. In conclusion, pigmented rice can enhance the technological and nutritional qualities of bread, bakery products, and snacks. Future researches should focus on agronomic advancement, optimization of pre-processing and processing techniques, exploring varietal differences among pigmented rice cultivars, and promotion of consumer awareness and market potentials. Full article

The co-contamination of cadmium (Cd) and tetracycline (TC) in an agricultural environment poses significant risks to plant growth and food safety. This study investigated their combined effects on rice seedlings by analyzing growth parameters, nutrient uptake, photosynthetic pigment levels, antioxidant enzyme activities, nonenzymatic antioxidants, osmoregulatory substances, and secondary metabolites. Results showed that TC alleviated the inhibition of Cd on rice seedling growth by inhibiting Cd accumulation, enhancing nutrient element absorption, facilitating the synthesis of photosynthetic pigments, increasing the activities of antioxidant enzymes and nonenzymatic antioxidants, and the levels of osmoregulatory substances and secondary metabolites. The research provided critical insights into the antagonistic toxicological effects of TC and Cd co-contamination in rice, offering significant information for environmental risk assessments and strategies to alleviate the influence of these pollutants on crop health. Full article

Nitrogen is a key element in promoting crop growth and development and improving photosynthesis. This study aimed to study the response of two rice genotypes to the restoration of N supply after varying periods of N deficiency. We used the low-nitrogen-tolerant rice Jijing 88 (JJ 88) and the nitrogen-sensitive rice variety Xinong 999 (XN 999) as test materials. The results of this study indicated that, compared to XN 999, JJ 88 has a higher content of the photosynthetic pigments. Photosynthesis in JJ 88 has strong adaptability under low-nitrogen conditions. Upon an increase in the nitrogen supply level, the maximum regeneration rate of ribulose biphosphate (RuBP, J_max) and the maximum carboxylation rate of RuBP (V_cmax) in JJ 88 showed a relatively large increase. The chlorophyll fluorescence parameters, including the effective quantum yield of photosystem II (Φ_PSII), the efficiency of excitation capture by open PSII centers (Fv′/Fm′), photochemical fluorescence quenching (qP), and the electron transfer rate (ETR) decreased slightly, while the non-photochemical fluorescence quenching (NPQ) increased slightly. Under low-nitrogen conditions, low-nitrogen-tolerant rice varieties maintain reasonable growth during the seedling stage. With an increase in the nitrogen supply level, the dry matter accumulation, photosynthetic pigment content, photosynthesis, and electron transfer ability of plants improve, but not to normal nitrogen supply levels. However, compared with XN 999, JJ 88 has a more proactive recovery ability. The research results provide valuable guidance for the breeding of nitrogen-efficient rice varieties and nitrogen fertilizer management. Full article

Colored rice (black, purple, red and brown) has been consumed in China for nearly 4000 years. Recent research has focused on exploring its nutritional and metabolomic profiles and associated health benefits. Due to the improvement in detection and quantification techniques for health-promoting compounds and their activities, the number of studies has increased significantly. In this regard, a timely and updated review of research on nutritional composition, phytochemistry, and metabolite content and composition can significantly enhance consumer awareness. Here, we present a detailed and up-to-date understanding and comparison of the nutritional and phytochemical (metabolite) composition of colored rice. While earlier literature reviews focus on either single type of colored rice or briefly present nutritional comparison or bioactivities, here we present more detailed nutrient profile comparison (carbohydrates, fats, proteins, amino acids, minerals, and vitamins), together with the most recent comparative data on phytochemicals/metabolites (flavonoids, anthocyanins, fatty acids, amino acids and derivatives, phenolic acids, organic acids, alkaloids, and others). We discuss how metabolomics has broadened the scope of research by providing an increasing number of detected compounds. Moreover, directions on the improvement in colored rice nutritional quality through breeding are also presented. Finally, we present the health-beneficial activities (antioxidant, anti-inflammatory, antimicrobial, hypoglycemic, neuroprotective, anti-aging, and antitumor activities) of different colored rice varieties, together with examples of the clinical trials, and discuss which bioactive substances are correlated with such activities. Full article

This study presents a comprehensive analysis of the chemical composition and bioactive properties of six newly cultivated varieties of pigmented and non-pigmented rice: Neunkeunheukchal (NKH), Neunkeunssal, Heukjagwang 709 (H709), Heukjagwang 1601, Hongjinju, and Hongchapssal (HCS). This study aims to characterize the chemical information and the industrial potential of lesser-known rice varieties. Significant differences were observed in the levels of phenolic compounds, flavonoids, γ-oryzanol, and free amino acids among these varieties, correlating with their antioxidant capacities. Among these varieties, NKH consistently exhibited the highest total phenolic, flavonoid, and γ-oryzanol contents, along with the strongest radical-scavenging activities, indicating its potential as a valuable functional food ingredient. Additionally, H709 and HCS demonstrated significant antioxidant activities, highlighting their potential roles in health-promoting applications. These findings highlight the potential of these varieties for functional food and nutraceutical applications. Future research should investigate the effects of cultivation conditions and processing methods on bioactive compound levels while conducting clinical trials to validate these health benefits in human models. The findings suggest that NKH, given its rich bioactive profile, may be particularly effective in managing oxidative stress and associated chronic diseases. Furthermore, the γ-oryzanol contents, the highest in NKH, highlight its potential for metabolic health benefits. This study lays the groundwork for future investigations into the development of functional foods and nutraceuticals derived from the unique characteristics of pigmented and non-pigmented rice varieties. Full article

Background/Objectives: Chronic lower respiratory tract inflammation can result from exposure to bacterial particles, leading to the activation of the NLRP3 inflammasome pathway. These effects may cause irreversible respiratory damage, contributing to persistent lung injury and chronic obstructive pulmonary disease (COPD), as observed in long COVID or bacterial pneumonia in older adults’ patients. Given its profound impact, the NLRP3 inflammasome has emerged as a key therapeutic target for mitigating aberrant inflammatory responses. Methods: In this study, we investigated the anti-inflammatory effects of Kum Akha black rice, a functional food, on the attenuation of NLRP3 inflammasome pathway using lipopolysaccharide-induced A549 lung epithelial cells and a C57BL/6NJcl mouse model. The anthocyanin-rich fraction from Kum Akha black rice germ and bran extract (KA1-P1) was obtained using a solvent-partitioned extraction technique. Results: KA1-P1 exhibited a high anthocyanin content (74.63 ± 1.66 mg/g extract) as determined by the pH differential method. The HPLC analysis revealed cyanidin-3-O-glucoside (C3G: 45.58 ± 0.48 mg/g extract) and peonidin-3-O-glucoside (P3G: 6.92 ± 0.29 mg/g extract) as its anthocyanin’s active compounds. Additionally, KA1-P1 demonstrated strong antioxidant activity, as assessed by DPPH and ABTS assays. KA1-P1 (12.5–100 μg/mL) possessed inhibitory effects on LPS + ATP-induced A549 lung cells inflammation through the significant suppressions of NLRP3, IL-6, IL-1β, and IL-18 mRNA levels and the inhibition of cytokine secretions in a dose-dependent manner (p < 0.05). Mechanistic analysis revealed that KA1-P1 downregulated key proteins in the NLRP3 inflammasome pathway (NLRP3, ASC, pro-caspase-1, and cleaved-caspase-1). Furthermore, in vivo studies demonstrated that KA1-P1 significantly diminished LPS-induced lower respiratory inflammation in C57BL/6NJcl mice, as evidenced by the reduced bronchoalveolar lavage fluid and blood levels of inflammatory cytokines (IL-6, IL-1β, and IL-18) and diminished histopathological inflammatory lung lesions. Conclusions: Overall, our findings suggest that the anti-inflammatory properties of KA1-P1 may support its application as a functional supplement or promote the consumption of pigmented rice among the elderly to mitigate chronic lower respiratory tract inflammation mediated by the NLRP3 inflammasome pathway. Full article

Pigmented rice, particularly the black and red varieties, is popular due to its better nutritional value. Anthocyanins and proanthocyanidins are two major flavonoid subcategories with broad physiological functions and therapeutic significance. However, pigment deposition is a complex process, and the molecular mechanism involved remains unknown. This review explores the metabolites responsible for the pigmentation in various rice tissues. Moreover, the current challenges, feasible strategies, and potential future directions in pigmented rice research are reported. Full article

The key flavonoid biosynthesis-related genes and their molecular features in rice have not been comprehensively and systematically characterized. In this study, we investigated the glumes of OsCSN1 mutants and OsCSN2 mutants and found the changes in the total flavonoid contents of the OsCSN2 mutants to be more pronounced than those of the OsCSN1 mutants and the changes in the anthocyanin contents of the OsCSN1 mutants to be more pronounced than those of the OsCSN2 mutants. In addition, key genes related to flavonoid synthesis, OsCHI, showed a more pronounced up-regulation trend, and the OsDFR gene, which encodes a precursor enzyme for anthocyanin synthesis, showed a clear down-regulation trend. And yeast two-hybrid experiments showed that OsCSN1 and OsCSN2 had the ability to interact with OsCUL4. In summary, OsCSN1 and OsCSN2 may regulate the metabolism of flavonoids in rice through CUL4-based E3 ligase, and the two subunits play different roles, laying a foundation for the study of the mechanism of flavonoid metabolism in monocotyledonous plants. Full article

As an agri-food by-product, the rice bran of pigmented rice, encompassing varieties such as red, black, and purple rice, has garnered increasing attention due to its richness in terms of bioactive compounds. Being mainly composed of the pericarp, aleuron, seed coat, and germ, the brown outer layer of the rice kernel offers potential health benefits and has applications in skincare. Human skin serves as the primary barrier against external threats, including pathogens, pollutants, and ultraviolet (UV) radiation. Notably, UV radiation accelerates the aging process and contributes to various skin issues. Recent trends suggest a heightened interest in incorporating pigmented rice into skincare regimens, motivated by its potential to mitigate oxidative stress, inflammation, and pigmentation, which are pivotal factors in skin aging and photodamage. With increasing consumer demand for natural and sustainable ingredients, pigmented rice has emerged as a promising candidate within the skincare and personal care sectors, effectively bridging the gap between nutrition and dermatological health. This review examines the applications of pigmented rice in skincare, with a particular focus on its bioactive components and potential mechanisms of action that contribute to skin health. The unique chemical composition of pigmented rice, which includes compounds such as anthocyanins, flavonoids, phenolic acids, and vitamin E, underlies its antioxidant, anti-inflammatory, and skin-protective properties. Despite the increasing recognition of its benefits, a comprehensive understanding of the underlying mechanisms remains limited, underscoring the necessity for further research to exploit the potential of pigmented rice in skincare applications fully. Full article

This study aims to explore the feasibility of producing submicrometer and nanometer cellulose fibers derived from rice husk treated with a novel method which selectively eliminate hemicellulose and lignin, while maintaining the integrity of the cellulosic and silica constituents. Three distinct processing methods are tested to extract the nanocellulose, namely hand milling, ball milling, and wet milling using a high-shear wet media mill from Masuko Sangyo Co., Ltd., Kawaguchi-city, Japan. A range of analytical methods, including Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDX), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA), are utilized to characterize the morphology, elemental composition, thermal stability, and chemical properties of the samples. The study revealed that among the tested methods, only wet milling successfully produced cellulose nanofibrils and silica nanoparticles, forming a biogenic organic–inorganic nanohybrid system. The nanofibers had lengths in the range of 120 nm and below, while the nanoparticles were in the tens of nanometers. The silica nanoparticles were found to adhere to the cellulose nanofibrils, forming a biogenic organic–inorganic nanohybrid system, with potential applications across diverse fields, including biomedical (drug delivery, biosensing, bone regeneration, and wound healing), cosmetic (skin and dental care), technical (insulating aerogels, flame retardants, and UV-absorbing pigments), and food applications (dietary supplements, thickeners). Full article

Lead (Pb) is a common contaminant that causes serious health and environmental problems. Thus, appropriate environmentally friendly and efficient techniques must be developed to remediate Pb in soils. Biochar (BC) has shown promise as an effective strategy to mitigate Pb toxicity. Trehalose (Tre) is a promising sugar that has been shown to effectively improve plant tolerance to abiotic stresses. Nonetheless, its role in alleviating Pb toxicity is unknown. The study investigated the impacts of BC and Tre co-application in alleviating Pb toxicity in rice crops. The study included the following treatments: control, Pb stress (250 mg kg⁻¹), Pb stress (250 mg kg⁻¹) + BC (2.5%), Pb stress (250 mg kg⁻¹) + Tre (30 mM), and Pb stress (250 mg kg⁻¹) + BC (2.5%) + Tre (30 mM). Results showed that Pb toxicity reduced rice yield by decreasing chlorophyll synthesis and relative water content (RWC), by increasing malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) contents, Pb accumulation in roots and shoots, soil available Pb concentration, and by decreasing the availability of soil nutrients. BC and Tre application mitigated the adverse impacts of Pb; however, more promising results were obtained with the co-application of BC and Tre. The results indicated that co-application of BC and Tre increased the rice yield by increasing photosynthetic pigments (46–96.42%), leaf water contents (16.67%), proline and soluble protein synthesis (35.13% and 24.96%), and antioxidant activities (12.07–31.67%), by decreasing root (59.72%), shoot (76.47%), and soil (57.14%) Pb concentrations, and the Pb translocation factor (15.08%). These findings suggested that co-application of BC and Tre can be a practical approach for reducing Pb toxicity, availability, and uptake, which improves rice productivity in Pb-polluted soil. Full article