Search Results (986)

Arsenic (As) is a highly toxic metalloid that can be absorbed by plants, inducing stress that disrupts vital physiological processes. In response, plants activate defense mechanisms that allow them to cope with As-induced stress. This review provides a comprehensive overview of the metabolic pathways involved in plant responses to As stress, focusing on the mechanisms of As uptake and transport, metabolic and antioxidant responses, molecular regulation, and mitigation strategies that contribute to plant adaptation and tolerance. As exposure disrupts primary metabolism by impairing photosynthesis, the Calvin cycle, and carbon and energy metabolism, while also altering aquaporin-mediated transport and phosphate homeostasis. In addition, As induces oxidative stress, leading to increased lipid peroxidation and enhanced activities of antioxidant enzymes, including superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR). It also affects secondary metabolism by modifying the biosynthesis and accumulation of specialized metabolites involved in stress tolerance. Overall, the evidence reviewed indicates that As can induce changes in both primary and secondary metabolic pathways. Although primary metabolic alterations are relatively well documented, information regarding changes in secondary metabolites, including phenolics and flavonoids, remains limited. Therefore, future research should integrate genomics, transcriptomics, proteomics, and metabolomics to elucidate the molecular basis of As tolerance and support modern crop breeding programs aimed at developing arsenic-tolerant cultivars. Moreover, this knowledge is fundamental for mitigating the impact of As on major food crops such as rice, wheat, maize, and vegetables, where arsenic contamination can reduce productivity, compromise crop quality, and increase the risk of As entry into the food chain. Furthermore, the mechanistic insights gained from these crops may serve as a basis for developing mitigation strategies applicable to other agriculturally important species. Full article

Rice bran oil (RBO) is a rich source of lipophilic bioactive compounds that may contribute to antioxidant, anti-inflammatory, and bone-health-promoting activities. This study investigated the effects of RBOs containing tocopherols, tocotrienols, and γ-oryzanol derived from Thai pigmented and non-pigmented rice cultivars on oxidative stress, inflammatory responses, and bone-remodeling-related activities. The content of tocopherols, tocotrienols, and γ-oryzanol was determined by high-performance liquid chromatography (HPLC). Reactive oxygen species (ROS) production was determined in human fetal osteoblast (hFOB 1.19) cells where nitric oxide (NO) and inducible nitric oxide synthase (iNOS) production were evaluated in RAW264.7 cells. Following compositional profiling and correlation analyses of antioxidant and anti-inflammatory activities, three representative RBOs were subsequently evaluated for their effects on bone-remodeling-related activities in hFOB 1.19 cells through alkaline phosphatase (ALP) activity and the production of osteocalcin (OC), osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-B ligand (RANKL). Additionally, calcification was investigated by Alizarin Red S staining. Pigmented RBOs, particularly Khao’ Hom Nil and RD69, contained higher levels of tocopherols, tocotrienols, and γ-oryzanol than non-pigmented RBOs. These oils significantly suppressed ROS, NO, and iNOS production, which correlated with tocopherol, tocotrienol, and γ-oryzanol content, while enhancing ALP activity, OC and OPG production, reducing RANKL levels and the RANKL/OPG ratio, and promoting matrix mineralization. Overall, pigmented RBOs represent promising natural sources of lipophilic bioactive compounds with potential antioxidant, anti-inflammatory, and bone-remodeling-related activities under in vitro conditions. Full article

Rice blast and bacterial blight are two major diseases that threaten rice production worldwide. Developing rice cultivars with both disease resistance and desirable grain quality is an important objective in modern rice breeding. In this study, R1179 carrying Pi2, Wx^b and Alk^b was crossed with IRBB7 carrying Xa7, Wx^b and Alk^b. Marker-assisted selection (MAS) was applied to an F₂ population of 1123 plants, and a line, G163, combining Pi2, Xa7, Wx^b and Alk^b, was developed. Disease resistance evaluation showed that G163 retained the blast resistance conferred by Pi2 and the bacterial blight resistance conferred by Xa7, exhibiting resistance to the tested isolates of both pathogens. Grain quality assessment indicated that G163 possessed favorable milling, appearance and eating quality traits. Rapid Visco Analyzer (RVA) profiling further indicated desirable starch pasting properties. In conclusion, the rice line G163 carrying Pi2, Xa7, Wx^b and Alk^b was successfully developed through MAS. The results provide a useful germplasm resource for breeding rice cultivars with combined disease resistance and desirable grain quality. Full article

Rice production in coastal tidal floodplains is severely constrained by periodic tidal submergence, making modern semi-dwarf varieties unsuitable. While local landrace cultivars are widely grown for their adaptability, their adaptation mechanisms and response to nitrogen management under tidal ecosystems remain poorly understood. This two-year on-farm study (aman seasons, 2021 and 2022) evaluated landrace rice cultivars against a modern check (BR23) under different nitrogen-management practices: urea super-granule deep placement and prilled urea application. Landraces adapted better to tidal submergence than BR23, exhibiting greater plant height, culm strength, biomass, and nutrient accumulation. Cultivar effects explained most of the variation in grain yield (38–40%), followed by nitrogen management (18–21%). Deep placement of urea super-granule significantly enhanced growth, yield, and nutrient uptake compared to prilled urea. Shorna showed the highest grain nitrogen uptake (48.23 kg ha⁻¹), agronomic efficiency (20.81 kg grain kg⁻¹ nitrogen), and partial factor productivity (71.91 kg grain kg⁻¹ nitrogen). Bhushiara achieved the highest grain harvest index (0.54) and nutrient harvest indices, indicating efficient nutrient partitioning to grains. During grain-filling, nitrogen and phosphorus efficiently remobilized to the grains, while potassium remained mostly in the straw. Ultimately, pairing resilient landraces like Shorna, Bhushiara, Dudmona, and Lalmota with optimized nitrogen management, specifically urea super-granule application, substantially improves productivity, nutrient efficiency, and climate resilience. This study provides some of the first comprehensive evidence on how genotype-specific adaptation and deep-placed nitrogen interact to support sustainable rice production in Bangladesh’s coastal floodplains. Full article

Irrigation water management in arid systems requires spatially distributed estimates of crop evapotranspiration (ET) that fixed crop coefficients cannot provide. The actual ET of flood-irrigated rice (Oryza sativa L.) on the arid northern coast of Peru was mapped with the METRIC surface energy balance model (Mapping EvapoTranspiration at high Resolution with Internalized Calibration) on Google Earth Engine (GEE). Ten cloud-free Landsat 8/9 scenes (January–July 2022) were processed over 113 ha at Ferreñafe (Lambayeque) on the 30 m product grid, onto which the 100 m native thermal observation was resampled, with internal calibration based on automatic anchor-pixel selection and hourly ERA5-Land data. Daily field-mean ET ranged from 4.2 to 8.1 mm d⁻¹, peaking during flooding and establishment and declining towards harvest. Because the same reference $E{T}_o$ underlies the METRIC internal calibration and the FAO-56 estimate, this is a comparison between two modelling approaches rather than an independent validation. Against the FAO-56 reference ET, METRIC showed a positive bias of $+0.65$ mm d⁻¹ (percent bias (PBIAS) $=+13\%$; root mean square error (RMSE) $=1.23$ mm d⁻¹; $r^2=0.57$; $n=9$, after excluding one date with anomalous reanalysis forcing), concentrated during flooding and after harvest, whereas at full canopy cover the two estimates converged. Two global ET products that share neither the METRIC formulation nor the ERA5-Land forcing reproduce the same seasonal decline once the canopy closes ($r=0.63$ and $0.91$) but stay far below in magnitude, as expected from their 500 m pixel. ET did not differ between sowing methods and varied only slightly among cultivars (∼0.3 mm d⁻¹), against marked intra-field variability. The METRIC–GEE workflow offers a low-cost, high-resolution tool for monitoring water use in data-scarce arid rice systems. Full article

Durum wheat is highly susceptible to Fusarium head blight (FHB), a severe fungal disease caused primarily by Fusarium graminearum. FHB affects durum wheat production by causing significant yield losses and grain contamination with mycotoxins such as deoxynivalenol (DON) and zearalenone (ZEA). Given the limitations of chemical fungicides, finding sustainable biological control agents is essential. This study evaluated the antagonistic and biocontrol capabilities of Trichoderma harzianum ITEM 3636 against F. graminearum through in vitro and greenhouse experiments. In vitro dual and sandwich culture assays demonstrated that T. harzianum significantly inhibits pathogen mycelial growth through direct interaction and the emission of volatile compounds. In a competition test on rice kernels, co-inoculation with ITEM 3636 significantly reduced pathogen biomass, leading to maximum reductions of 96.5% for DON and 98% for ZEA. Furthermore, greenhouse trials on a commercial durum wheat cultivar revealed that T. harzianum ITEM 3636 significantly decreased FHB severity by 40% and reduced DON contamination by up to 32% only when a combined seed-coating and spike-spraying application was performed. Additionally, ITEM 3636 exhibited biostimulant-like effects on yield parameters, causing an increase in kernel weight of 33% in the greenhouse assay. These findings highlight T. harzianum ITEM 3636 as a promising and ecological alternative to synthetic fungicides for managing FHB, safeguarding crop production, and ensuring food safety. Full article

Background: Rice breeding requires faster development of high-yielding, climate-resilient, resource-efficient, and high-quality cultivars for production systems exposed to environmental variability and increasing input constraints. Genomic selection offers an opportunity to predict breeding value before extensive field evaluation, although its effectiveness depends on the integration of genomic, phenotypic, and environmental information. Methods: This narrative review critically examines recent advances in genomic selection for rice and its integration with high-throughput genotyping, high-throughput phenotyping, machine learning, multi-environment prediction, and speed breeding. Results: Genome-wide marker data can support early ranking of breeding materials for grain yield, grain quality, disease resistance, drought tolerance, salinity tolerance, and nutrient-use efficiency. Prediction performance is influenced by trait architecture, marker density, training-population size, genetic relatedness between training and candidate populations, phenotypic data quality, and genotype-by-environment interaction. Red-green-blue, multispectral, hyperspectral, thermal, and light detection and ranging platforms can generate temporal traits associated with plant architecture, biomass, water status, nutrient status, and stress responses, which may improve prediction under suitable population and validation designs. Speed-breeding systems shorten generation intervals and facilitate rapid advancement, recurrent selection, and recycling of superior parental lines. Conclusions: Integrated breeding pipelines that combine genomic prediction, high-throughput phenotyping, environmental data, and speed breeding can improve selection efficiency and shorten rice improvement cycles. Wider adoption will require affordable technology platforms, standardized data systems, multi-environment validation, breeder capacity development, and collaborative data-sharing frameworks for smart and greener agriculture. Full article

Balancing high grain yield with improved nitrogen use efficiency is a critical challenge in intensive rice production systems. Although both nitrogen application rate and planting density are recognized as major determinants of yield, their synergistic physiological mechanisms, particularly in large-panicle Indica–Japonica hybrid rice, remain insufficiently understood. A two-year (2023–2024) split-plot field experiment was conducted using the high-yield cultivar Yongyou 7860. Treatments included five nitrogen application rates (N0: 0; N12: 180; N14: 224; N16: 240; N20: 300 kg ha⁻¹) and three planting densities (D1: 220,000; D2: 190,000; D3: 160,000 plants ha⁻¹). Grain yield, yield components, canopy chlorophyll status (SPAD value), dry matter accumulation, partial factor productivity of nitrogen, and activities of glutamine synthetase (GS) and glutamate synthase (GOGAT) at critical growth stages were determined. Nitrogen rate and planting density exhibited significant interactive effects on grain yield and nitrogen use efficiency. Grain yield increased with nitrogen application rate but showed a quadratic response to planting density, with an optimum at the medium density. The N16D2 treatment consistently achieved 11.3–11.8 t/ha over two years, exceeding conventional practices by 1.7–9.7%, primarily attributed to a 6.3–11.5% increase in the number of effective panicles. Physiologically, N16D2 sustained higher SPAD values and dry matter accumulation comparable to excessive nitrogen input, while enhancing the partial factor productivity of nitrogen by 33.0% relative to N20D3. Enhanced activities of GS and GOGAT under N16D2 indicated improved nitrogen assimilation capacity. In summary, reduced nitrogen application coordinated with increased planting density optimizes canopy structure, promotes efficient nitrogen metabolism, and sustains high grain yield in Indica–Japonica hybrid rice. This study provides a scientifically grounded and practically applicable strategy for achieving high productivity with improved nitrogen use efficiency in intensive rice systems. Full article

Nitrogen (N) fertilizer regulates leaf photosynthesis and dry matter production in rice, and extensive genotypic differences in N responsiveness exist among cold-region japonica rice cultivars. A two-year field experiment was conducted in the city of Jiamusi, Heilongjiang Province, during 2023–2024, using two representative japonica cultivars: the small-panicle cultivar Longjing 47 (LJ47) and the large-panicle cultivar Longjing 3010 (LJ3010). A split-plot design was adopted with four N application rates (0, 110, 138, and 166 kg N·ha⁻¹) and four basal–tiller to panicle–grain N ratios (10:0, 8:2, 7:3, and 6:4). The results showed that increasing N supply significantly enhanced SPAD values, photosynthetic capacity, leaf area index, and total dry matter accumulation in both cultivars. LJ47 maintained high photosynthetic capacity under moderate N supply, whereas LJ3010 required higher N input to sustain superior photosynthetic performance. From heading to maturity, dry matter accumulation, photosynthetic potential, crop growth rate, net assimilation rate, N uptake, and grain yield all increased with an increasing ratio of panicle–grain N fertilizer, with more pronounced improvements observed in LJ3010. LJ47 achieved optimal physiological performance and grain yield at 138 kg N·ha⁻¹ (moderate N), with no further promotion under high-N supply. In contrast, LJ3010 required 166 kg N·ha⁻¹ (high-N) to maintain photosynthetic advantages and achieve higher grain yield in the late growth stage. Increasing the proportion of basal–tiller N fertilizer favored the source sink balance of LJ47, while increasing panicle–grain topdressing delayed leaf senescence and promoted post-heading dry matter translocation in LJ3010. For a target grain yield of 9 t·ha⁻¹, the recommended N rate is 138 kg·ha⁻¹ with a basal–tiller to panicle–grain N ratio of 8:2–7:3 for LJ47, and 166 kg·ha⁻¹ with a ratio of 7:3–6:4 for LJ3010. This study provides a theoretical basis and data reference for the formulation of precise N fertilization strategies that match fertilizer management with rice cultivar characteristics in cold regions. Full article

The brown planthopper (BPH, Nilaparvata lugens) is a major insect pest of rice (Oryza sativa L.) causing severe yield losses across Asia. Although the resistance gene OsBph32 from the cultivar Ptb33 enhances BPH resistance, its molecular and physiological mechanisms remain unclear. Here, we investigated its function using OsBph32-overexpressing lines combined with physiological, transcriptomic, and metabolomic analyses. Overexpression of OsBph32 in the susceptible cultivar 9311 significantly increased resistance to BPH, as indicated by reduced plant damage and suppressed insect growth. This was associated with increased reactive oxygen species accumulation and callose deposition, suggesting activation of early defense responses. Multi-omics analyses revealed that OsBph32 is associated with transcriptional changes in genes involved in cell wall biosynthesis, phenylpropanoid metabolism, and carbon metabolism. Metabolomic profiling further showed increased accumulation of flavonoids, phenolamides, and lignin-related metabolites under BPH infestation, together with changes in carbon metabolism and starch accumulation. Collectively, these results suggest that OsBph32 is associated with coordinated changes in structural reinforcement, secondary metabolism, and carbon metabolism during insect attack, which may contribute to enhanced rice resistance and provide new insights into non-NLR-mediated insect defense mechanisms in plants. Full article

Low-light environments severely affect rice yield and quality. As an important raw material for rice noodles, improving rice yield and quality under low-light conditions is very important. In this study, the grain-filling dynamics, yield, processing quality, and appearance quality of two rice noodle-specific cultivars, i.e., Gui Chao II (GCII) and Guangyou 2928 (GY2928), were investigated under shading in Sichuan. At the experimental site, the soil type is loam, average temperature reaches 23.1 °C, total rainfall reaches 780–830 mm, and total sunshine duration is about 760 h. A two-factor split-plot design was conducted. Two light intensities (natural light vs. 51% shading) served as the main plot, and two rice cultivars (GCII and GY2928) served as the subplot, and each was replicated three times. Results showed that, compared with normal light, shading reduced the average filling rate (Vmean) of GCII and GY2928 by 20.67% and 18.69%, the maximum filling rate (Vmax) decreased by 20.26% and 16.18%, the 100-grain weight (Gmax) at the maximum filling rate decreased by 0.42 g and 0.21 g, and the active filling period (D) was shortened by 1.47 days and 4.01 days, respectively. Compared with normal light, the decreased grain filling led to a significant decrease in spikelet fertility by 30.62% and 28.50% for GCII and GY2928 under shading. Finally, the yield of GCII and GY2928 significantly decreased by 25.33% and 27.82% compared with normal light. Compared with normal light, shading increased the head rice rate of GCII, while that of GY2928 was significantly reduced. In contrast, the chalkiness rate and chalkiness degree of GCII under shading were significantly reduced, but those of GY2928 significantly increased. In conclusion, GCII exhibited more stable yield and quality under shading, and breeding and planting such varieties could increase rice yield and quality in low-light environments. Full article

Ratoon rice cultivation is a significant practice for enhancing land productivity and food security. Ratooning ability is a key determinant of ratoon season crop (RC) yield and is influenced by genetic, agronomic, and hormonal factors. This study aimed to evaluate the effects of foliar-applied ratooning enhancers, formulated with plant hormones and botanical extracts, on the growth and regeneration of a japonica–indica hybrid rice cultivar, ‘Qingxiangyou 19 Xiang’. Treatments included gibberellin (GA), low, medium, and high concentrations of brassinosteroid (BR), each with or without jasmine extract (JE), alongside proline and zinc chloride (ZnCl₂) as supporting components. These solutions were applied twice at 5 and 15 days after flowering (DAF) of the main crop (MC). The results showed that GA treatment increased plant height and panicle length but reduced MC tiller number. BR treatments did not affect plant height but significantly increased the 1000-grain weight. Crucially, while BR alone had no significant effect on ratooning ability, the BR-JE combined application, particularly at medium (MBR-JE) and high (HBR-JE) concentrations, significantly increased ratoon tiller number and enhanced ratooning ability. However, the HBR-JE combination increased grain chalkiness. In conclusion, the foliar application of BR combined with JE during the flowering stage effectively promotes ratooning ability without compromising MC yield, offering a promising agronomic strategy for sustainable ratoon rice production. Full article

Potato is the third most important food crop in the world after maize and rice. Its importance stems from its contribution to food security in most parts of the world. Although the crop is widely cultivated globally, it faces numerous biotic and abiotic challenges, among which plant-parasitic nematodes pose a significant threat. The objective of the study is to map the nematode species affecting potato crops while drawing links with their pervasiveness and outlining effective control strategies. The article selection process followed the PRISMA guidelines. A total of 41 articles were selected for the review from an initial 944 records retrieved from the Web of Science, Scopus, CAB Abstract, and reference list based on their relevance to the study criteria. The findings indicate that G. pallida, G. rostochiensis, M. incognita and M. javanica were the most reported nematodes globally. Chemical and biological control remain the most widely used management strategies, while incorporating resistant cultivars, abiotic inducers, organic fertilizers, and crop rotation offers greater potential to enhance the sustainability and resilience of farming systems. A significant global research gap persists in nematode surveillance and diagnostic surveys of potato-growing regions. Full article

Improving rice yield and optimizing rice quality are of great significance for ensuring food security. In modern rice production, mechanical transplanting has become the dominant transplanting method. Precise regulation of plant spacing and row spacing contributes to the formation of different transplanting densities, which further exerts effects on photosynthetic spikelets filling, yield formation and quality development of rice. Two-year field experiments were conducted with two conventional japonica rice cultivars of contrasting yield levels under four transplanting hill spacings at a uniform row spacing of 30 cm. The results showed that rice cultivars with higher seed-setting rate with an increase ranging from 1.44 to 1.91% and larger grain weight with an increase ranging from 13.17 to 13.40% presented more prominent yield potential. In addition, high-yield rice cultivars possessed more excellent photosynthetic carbon metabolism characteristics, which effectively improved the spikelets filling process of rice kernels. Superior photosynthetic carbon metabolism characteristics were conducive to increasing head rice rate and reducing chalkiness, while maintaining the duration of spikelets filling benefited the improvement of rice taste value. Narrowing the transplanting plant spacing reduced the physiological enzyme activities in rice leaves and grains, weakened photosynthetic carbon metabolism and hindered spikelets filling, which further decreased head rice rate and protein content but increased chalkiness. Notably, rice taste value also showed an increasing trend. The taste value of superior spikelets (SSs) of the two rice cultivars increased by 1.97–5.11% and 0.98–2.60% respectively, and that of inferior spikelets (ISs) increased by 1.37–3.64% and 1.62–4.12% respectively. Reducing transplanting plant spacing also significantly increased the number of effective panicles, resulting in an increase in population spikelet number. The final yield of the two rice cultivars increased by 5.38–11.62% and 5.23–11.03% respectively. Full article

2-acetyl-1-pyrroline (2-AP), the key volatile compound responsible for aroma in aromatic rice, is highly susceptible to abiotic stresses such as cadmium (Cd) toxicity. However, the potential role of molybdenum disulfide nanoflakes (MoS₂FL) in regulating antioxidant defense and 2-AP biosynthesis under Cd stress remains largely unexplored. In this study, a pot experiment was conducted to evaluate the effects of foliar MoS₂FL application on antioxidant defense, aroma formation, and Cd-stress mitigation in two fragrant rice cultivars, Meixiangzhan-2 and Basmati, grown in Cd-contaminated soil (50 mg kg⁻¹). Cadmium stress significantly reduced key enzymes and precursors involved during 2-AP biosynthesis, including Δ1-pyrroline-5-carboxylate synthetase (P5CS), Δ1-pyrroline, pyrroline-5-carboxylic acid (P5C), diamine oxidase (DAO) and proline dehydrogenase (PRODH), along with downregulation of their associated genes. In contrast, foliar application of MoS₂FL was associated with reduced Cd-induced oxidative stress, as indicated by increased antioxidant enzyme activities (SOD, POD, and CAT) and decreased malondialdehyde (MDA) accumulation. Moreover, MoS₂FL increased precursor accumulation, enzymatic activities, and transcript abundance of genes associated with 2-AP biosynthesis, whereas gamma-aminobutyric acid (GABA) content, betaine aldehyde dehydrogenase (BADH) activity, and BADH2 gene expression were significantly reduced. Consequently, MoS₂FL application significantly increased 2-AP content by 44.47% in Meixiangzhan-2 and 39.94% in Basmati under Cd stress. These findings suggest that MoS₂ nanoflakes may serve as a promising nano-enabled strategy to enhance antioxidant defense, improve aroma quality, and mitigate cadmium stress in fragrant rice, potentially through changes associated with the 2-AP biosynthesis pathway. This study highlights the potential application of nanomaterials in improving crop quality and stress resilience in sustainable agricultural systems. Full article