Search Results (889)

Wet direct-seeded rice (WDSR) is a resource-efficient cultivation system gaining global popularity, but its sustainability is severely threatened by weedy rice (Oryza sativa f. spontanea). Due to the high genetic and physiological similarities between weedy and cultivated rice, selective chemical control remains a formidable challenge. This study evaluated an integrated chemical control strategy utilizing the safener metcamifen (applied as a seed coating) to protect cultivated rice from the pre-emergence herbicide pretilachlor in a simulated WDSR system. Indoor bioassays and outdoor mock-plot trials revealed that metcamifen seed coating alone (up to 560 mg a.i. kg⁻¹ seed) significantly promoted early seedling vigor in cultivated rice (‘Jia 67’) without exhibiting phytotoxicity. Conversely, soil application of pretilachlor at 375 g a.i. ha⁻¹ provided effective initial herbicidal activity, suppressing weedy rice emergence to merely 7.0%. Under this severe herbicide stress, metcamifen seed coating at an effective dose of 480 mg a.i. kg⁻¹ seed significantly mitigated phytotoxicity. However, this protection was partial; crop emergence was maintained at 63.8%, substantially preserving seedling biomass compared to the non-safened control (28.3%), but still reflecting a clear emergence penalty. We hypothesize that this moderate reduction in initial crop stand could potentially be compensated by proportionally increasing the initial seeding rate—a potential agronomic compromise that warrants future empirical validation in the field. In summary, this study provides a preliminary, controlled-environment evaluation demonstrating that the protective application of metcamifen with pretilachlor offers a potential framework for mitigating weedy rice infestations, subject to further field-scale verification. Full article

Maize (Zea mays L.), a typical thermophilic crop originating from tropical regions, exhibits an inherent sensitivity to low-temperature stress. Cold stress severely restricts maize seed germination, seedling growth, the physiological metabolism, and the final grain yield, which greatly limits its geographical cultivation range and sustainable industrial development. Elucidating the molecular regulatory mechanisms underlying maize cold tolerance and excavating cold-resistant functional genes are essential for the molecular breeding of cold-tolerant maize varieties and expanding maize planting areas in high-latitude and low-temperature-prone regions. In this study, using the strongly cold-tolerant maize inbred line B144 as the experimental material, we cloned the ZmMAPKKKA gene (NCBI accession: LOC103651289) and systematically screened and verified its cold-stress-specific interacting proteins via multiple molecular biological assays. The full-length coding sequence (CDS) of ZmMAPKKKA is 1134 bp, encoding a 377-amino-acid protein with a predicted molecular weight of 40.37 kDa. The quantitative real-time PCR (qRT-PCR) results demonstrated that the ZmMAPKKKA expression was significantly upregulated by 16.56-fold in maize roots after 12 h of low-temperature treatment, indicating a tissue-specific and robust cold response in root tissues. A total of 25 interacting proteins were identified through yeast two-hybrid screening, among which three stress-responsive proteins, including a protein kinase (LOC100286253), a protein phosphatase 2C (PP2C) (LOC542176), and a NAC transcription factor (LOC118474710), were selected for subsequent verification. The Pull-Down, Co-immunoprecipitation (Co-IP), and bimolecular fluorescence complementation (BiFC) assays consistently confirmed that ZmMAPKKKA specifically interacts with these three proteins both in vitro and in vivo under cold stress conditions. This study is the first to construct a ZmMAPKKKA-centered protein interaction module in the maize mitogen-activated protein kinase (MAPK) cascade under cold stress, establishing a novel kinase–phosphatase–transcription factor regulatory cascade that improves the current understanding of cold signal transduction mechanisms in maize. Homologous genes of ZmMAPKKKA in gramineous crops including rice (Oryza sativa) and sorghum (Sorghum bicolor) have been proven to participate in diverse abiotic stress responses, suggesting the conserved functional roles of MAPKKK family genes across gramineous species. Collectively, our findings provide comprehensive insights into the molecular mechanism of the maize MAPK signaling pathway mediating cold stress adaptation and supply valuable functional gene resources for cold-tolerant maize germplasm innovation and molecular breeding. Full article

Nitrogen (N) is an essential macronutrient for plant growth. NIN–like protein (NLP) transcription factors play important roles in nitrate signaling and response in plants. However, a comprehensive analysis of the NLP gene family in sorghum is still lacking. In this study, we identified five NLP genes in sorghum, and a high collinearity of NLP was detected in sorghum, rice and maize. N deficiency decreased SbNLP3 and SbNLP4 expression levels in roots, and the expression of SbNLP1 and SbNLP2 declined in roots during nitrate resupply. Subcellular localization analysis revealed that SbNLP1 was mostly detected in nuclei and cytoplasm. Compared with wild–type rice ZH11 plants, SbNLP1 overexpression plants showed improved low nitrogen (LN) tolerance, with longer roots and shoots under LN conditions. Transcriptome analysis between overexpression lines OE1–5 and ZH11 showed that 773 and 967 differentially expressed genes (DEGs) were identified in roots and shoots under LN conditions, respectively. In contrast, 674 and 1283 DEGs were identified in roots and shoots under normal nitrogen (NN) conditions, respectively. Thirty–seven N–related DEGs were identified in roots through GO enrichment under LN conditions, and terms of plant hormone signal transduction, biosynthesis of secondary metabolites and plant–pathogen interaction were identified through KEGG enrichment. WGCNA analysis also revealed plant hormone signal transduction pathways and plant pathogen interaction pathways in OE1–5 under LN conditions. These results provide a basis for N use efficiency (NUE) improvement in sorghum and functional analysis of SbNLPs. Full article

To address the dual challenges of discriminating weeds from rice seedlings for precision weed management operations, such as targeted spraying and robotic weeding, in complex paddy-field scenes and deploying high-precision models on resource-limited edge devices, we propose DGS-Net, a deformable attention, GSConv-based feature fusion, and SEAM-enhanced lightweight network based on YOLOv11n. The backbone incorporates a convolutional block with parallel split attention and deformable attention transformer (C2PSA_DAT) module to improve the extraction of irregular and fine-grained weed features, the neck integrates a VoV-GSCSP module to enable lightweight multi-scale feature fusion for small and densely distributed targets, and a separated and enhancement attention module (SEAM) is placed before the detection head to enhance robustness under leaf occlusion and complex paddy-field background interference. In comparative experiments conducted on the paddy-field dataset under unified training and evaluation settings, DGS-Net achieved 91.7% precision, 86.8% recall, and 92.4% mean average precision (mAP), with a model size of 5.8 MB and a computational cost of 6.2 giga floating-point operations (GFLOPs). Compared with representative lightweight baseline detectors, DGS-Net showed a more favorable balance between detection accuracy and deployment efficiency. In additional edge-device deployment tests using the test set, the model sustained real-time inference at 32.5 FPS and achieved mAP@0.5, precision, and recall of approximately 0.928, 0.919, and 0.867, respectively. Overall, DGS-Net improves irregular feature extraction, enables lightweight multi-scale feature fusion, and increases robustness to occlusion while retaining strong deployability. The method therefore provides practical visual-perception support for precise, real-time crop–weed discrimination and precision weed management in complex paddy-field environments. Full article

Rice cultivation faces major environmental challenges due to climate change, particularly soil salinity, which limits plant growth and productivity. Salt tolerance in rice is typically evaluated using physiological and biochemical traits, whereas leaf anatomical traits combined with advanced statistical analyses remain underexplored. This study investigated leaf anatomical characteristics of the rice cultivar Tubtim Chumphae at the seedling stage under different salinity levels (0, 25, 50, 75, and 100 mM NaCl). Seedlings were cultivated in a soil-based pot system for 42 days prior to treatment, and salinity stress was applied for 4 weeks. Data were analyzed using the Kruskal–Wallis test and multivariate approaches, including Discriminant Analysis of Principal Components (DAPC) and Partial Least Squares Discriminant Analysis (PLS-DA). The results revealed that several anatomical traits significantly varied with salinity, including vertical epidermal cell size of long cells (Epi-VL-LC), major vascular bundle size in the lamina (MVB-la-HL), major vascular bundle size in the midrib (MVB-mid-HL and MVB-mid-VL), as well as stomatal size (St-HL and St-VL) and stomatal density (StD) (p < 0.01). DAPC effectively distinguished salinity levels based on leaf anatomical traits, and the PLS-DA results further supported the robustness of the classification. Epidermal cell size, cell wall and cuticle thickness, stomatal traits, and vascular bundle dimensions were identified as key candidate anatomical biomarkers of salt tolerance. S75 (75 mM NaCl treatment) was suitable as a screening level and S100 (100 mM NaCl treatment) as a confirmation level. The findings provide a useful reference for evaluating salt tolerance in this rice cultivar and may be integrated with morphological, physiological, and biochemical traits to support future rice breeding programs. These findings provide a reference for evaluating salt tolerance in this cultivar and may complement morphological, physiological, and biochemical traits in future rice breeding programs. Full article

Chlorophylls are the major light-harvesting pigments in photosynthetic organisms. Their biosynthesis requires the coordinated supply of metabolic intermediates from two independent upstream branches: the methylerythritol 4-phosphate (MEP)-derived terpenoid pathway, which supplies the phytyl side chain via geranylgeranyl diphosphate (GGPP), and the tetrapyrrole biosynthesis pathway (TBP), which provides the porphyrin ring. How flux through these two branches is coordinated remains poorly understood. In this study, we report the identification of a direct protein–protein interaction between δ-aminolevulinic acid dehydratase (ALAD), the second enzyme of the TBP, positioned immediately upstream of the first metabolic branch point, and the Type II small subunit of GGPP synthase (SSUII), a key regulator of terpenoid flux toward chlorophyll biosynthesis. ALAD was identified as a candidate SSUII-interacting protein by co-immunoprecipitation coupled with LC-MS analysis of rice leaf tissue, with a sequence coverage of 57.04%. The interactions between OsALAD1 and OsSSUII in rice, and between AtALAD1 and AtSSUII in Arabidopsis thaliana, were validated by yeast two-hybrid assay and bimolecular fluorescence complementation (BiFC) in Arabidopsis protoplasts. BiFC imaging demonstrated that the interaction is localized to the chloroplast. Sequence analysis revealed that plant ALAD proteins are highly conserved, with 92% similarity between OsALAD1 and AtALAD1, and 76.9% similarity between OsALAD1 and the green alga Chlamydomonas reinhardtii CrALAD1, indicating cross-species conservation of the ALAD–SSUII interaction. In vitro enzyme activity assays showed that AtSSUII does not directly alter AtALAD1 catalytic activity, suggesting the interaction operates through post-translational rather than direct catalytic mechanisms. Overexpression of AtALAD1 caused severe chlorosis and seedling lethality, while AtSSUII overexpression produced no distinct phenotype; neither transgene altered the transcript level of the other. Together, our results reveal a conserved cross-pathway protein–protein interaction linking the terpenoid regulatory machinery to the early TBP, suggesting a molecular possibility for the coordinated regulation of chlorophyll biosynthesis. Full article

Rice seedlings are typically grown in high-phosphorus nursery soils in practice, which reduces rice root growth and the plant’s ability to adapt to adverse conditions after transplantation to the paddy field. Thus, it is important to improve rice root development in high-phosphorus nursery soils. Rice root developments are closely connected with soil microorganisms. Arbuscular mycorrhizal fungi (AMF) can promote rice root growth and help improve rice performance in resisting adverse conditions. To illustrate the mechanisms of rice seedlings with AMF inoculation under suitable and high-phosphorus nursery soils in resisting adverse conditions, rice seedlings were cultivated in suitable and high-phosphorus nursery soils inoculated with AMF JD5 (Paraglomus sp.) and transplanted into soda saline–alkaline soils following successful AMF inoculation. Results showed that under high-phosphorus conditions, AMF JD5 inoculation significantly promoted plant height and root elongation, likely through increased total chlorophyll content. Concurrently, proline content was reduced, whereas soluble sugar and soluble protein contents were elevated, indicating alleviation of osmotic stress induced by saline–alkaline conditions. Moreover, AMF JD5-inoculated seedlings exhibited increased CAT activity, which efficiently scavenged reactive oxygen species (ROS) generated under salt–alkaline stress and reduced lipid peroxidation. However, thiobarbituric acid reactive substances (TBARS) content was significantly decreased with AMF inoculation in high-phosphorus conditions. Collectively, these findings suggest that AMF JD5 inoculation in high-phosphorus nursery soils establishes a physiological and biochemical foundation that maintains rice resilience against saline–alkaline stress throughout early growth. Full article

Soil salinization severely restricts rice growth and global grain production, posing a serious threat to food security. Dongxiang wild rice serves as an important genetic resource for improving salt tolerance in rice. In this study, a backcross inbred line (BIL) population derived from Dongxiang wild rice DY80 and an indica restorer line R974 were used to detect QTLs for salt tolerance at the germination and seedling stages. Four QTLs related to germination-stage salt tolerance and three QTLs for seedling-stage salt tolerance were identified, among which qSTS5 on chromosome 5 showed the largest effect with a LOD score of 8.0 and a phenotypic contribution rate of 14.8%. An F_2:3 population was further constructed to validate qSTS5, which increased its LOD value to 10.4 and phenotypic variation explanation rate to 18.5%, and the locus was finally delimited to a 2.3 Mb interval. Transcriptome analysis identified eight differentially expressed genes (DEGs) within the qSTS5 region under salt stress. Sequence comparison between the parents revealed that three DEGs had no coding-region variations, while the other five showed nucleotide polymorphisms leading to amino acid changes. Among them, Os05g0349800 encodes a LEA protein, a typical stress-responsive gene, and harbors a frameshift mutation in DY80. Combined with its induced expression pattern under salt stress, this gene was considered the most promising candidate for qSTS5. This study not only provides a stable major QTL for rice breeding for salt tolerance but also lays a foundation for dissecting the molecular mechanism of salt tolerance in Dongxiang wild rice. Full article

Agricultural waste streams represent an underutilized source of bioactive compounds with potential to enhance crop resilience under climate stress. We previously showed that volatile compounds (VCs) emitted from waste shiitake fungi beds (WSFBs) promote early rice seedling growth under controlled conditions. Here, we evaluated whether these early-stage effects persist after transplanting and translate into agronomic benefits under field conditions, including the record high temperatures (HTs) of the 2023 growing season in Niigata, Japan. Seedlings of two japonica cultivars, Nipponbare and Koshihikari, were exposed to WSFBs-derived VCs using a non-contact system and subsequently grown in paddy fields across two seasons (2023–2024). WSFBs-VCs-treated (+VCs) plants exhibited enhanced seedling vigor, increased tiller and panicle numbers, higher grain yield per plant, greater 1000-grain weight, and reduced grain chalkiness. Gas exchange measurements at the reproductive stage during the 2023 record HT showed that +VCs plants maintained higher net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, and transpiration rate, while intrinsic water-use efficiency showed a modest decline consistent with transpirational cooling. Controlled-environment assays revealed enhanced physiological stability supported by upregulation of cytokinin and stress-responsive genes under acute heat stress. Together, these results demonstrate that short-term exposure to WSFBs-derived VCs enhances rice performance under field conditions, including during extreme heat, and highlight their potential as low-cost, waste-derived biostimulants that support sustainable, circular, and climate-resilient rice production. Full article

Salinity stress is a major constraint affecting rice establishment and productivity in many coastal and salt-affected regions of the world, as well as in Bangladesh. Seed priming has emerged as an effective technique to enhance seed germination, seedling vigor and growth, and stress tolerance. To address this challenge, the present study investigated the potential of four different seed-priming agents (non-, hydro-(H₂O), osmo-(Polyethylene glycol, 30%), nano-(Zinc EDTA (12%), and 170 ppm) applied to two rice varieties (Binadhan-10 and BINA dhan25) under four levels of salinity stress (0, 5, 8, and 11 dS m⁻¹), with the aim of enhancing germination, improving the seedling vigor index, and promoting early growth performance in a completely randomized design with four replications. Nano-priming with Zinc EDTA (12%, at 170 ppm) involves soaking seeds in a solution containing this concentration of zinc chelate, which can improve seedling vigor and stress resilience, especially under challenging conditions like salinity. The results indicated that salinity significantly reduced germination and seedling growth, whereas seed priming improved seed performance under stress conditions. Among the treatments, nano-priming showed the most pronounced improvement in germination and seedling vigor. Binadhan-10 exhibited a greater tolerance to salinity compared with BINA dhan25. Multivariate analyses, including principal component analysis, correlation analysis, and heatmap, revealed strong positive relationships among germination, vigor index, and seedling biomass traits. The findings demonstrate that seed priming, particularly nano-priming, can effectively enhance rice seed germination, the vigor index, and different seedling traits under saline conditions, providing a promising strategy for improving rice production in salt-affected areas in Bangladesh. Full article

Effective weed control is essential for sustainable and safe rice production, particularly under the long-term and widespread use of chemical herbicides. Oilseed rape (Brassica napus L.) is one of the most important oil crops worldwide, and the oilseed rape–rice rotation system is widely practiced in China. It has been reported to exhibit strong allelopathy on various plants, but the feasibility of using its straw incorporation for weed control in transplanted rice fields remains unclear. In this study, a natural weed management strategy based on shallow tillage of oilseed rape straw (ORS) was evaluated through laboratory bioassays, greenhouse experiments, and field trials. The results indicated that soil decomposition liquids (SDLs) of ORS exhibited strong dose- and decomposition time-dependent allelopathic effects on seven paddy weed species, while rice showed markedly lower sensitivity. ORS incorporated at 700–1100 g/m² generally exhibited high integrated allelopathic inhibition (in lab) and population control effects (in greenhouse) on paddy weeds, especially Leptochloa chinensis (L.) Nees, Cyperus iria L., and Cyperus difformis L. Among the growth parameters of ORS allelopathic stress, root growth was the most sensitive indicator, followed by shoot growth and seed germination. Greenhouse experiments displayed variety-dependent impact on the transplanted rice seedlings, with Xiushui134 and Yongyou1540 showing relatively high tolerance. Field trials revealed that ORS incorporation at 1100 g/m² for 10 d achieved a satisfactory control of population (77.7–84.9%) and fresh weight (80.7–95.6%) across Gramineae, Cyperaceae and Broadleaf weeds, without adverse impact on the growth of transplanted rice seedlings (Yongyou1540). This treatment also significantly promoted theoretical grain yield by 13.4–19.4%. Overall, shallow tillage of oilseed rape straw provides a feasible and environmentally friendly weed control strategy for transplanted rice systems. Full article

Accurate identification of plant numbers is crucial for evaluating the effectiveness of mechanical rice seedling transplanting, which directly affects yield estimation and replanting decisions in precision agriculture. Conventional manual counting methods are time-consuming and labor-intensive, which hinders their application in modern agriculture, where efficiency and precision are paramount. Therefore, this study constructed a dataset based on images collected by consumer-grade Unmanned Aerial Vehicles (UAVs) and proposed an improved lightweight detection model named CLR-YOLO (Complex-scene Lightweight Rice-detection YOLO) based on the YOLOv11n. The model replaces the original C3k2 module with C3k2-PConv to improve computational efficiency while maintaining feature extraction capability. Additionally, it reconstructs the neck network using the Heterogeneous Selective Feature Pyramid Network (HSFPN) to optimize the handling of features from both large and small targets. Finally, the PConvHead detection head is designed to enhance feature utilization efficiency and reduce both false positives and missed detections in dense rice seedling scenarios. Experimental results demonstrated that CLR-YOLO achieved an average precision (AP@0.5) of 93.9%. While maintaining comparable accuracy, the model reduced parameters to 1.4 M, computational cost to 3.7 GFLOPs, and model size to 2.9 MB—reductions of 46.2%, 41.3%, and 44.2%, respectively, compared to the baseline model. This model provides significant support for rice seedling detection and offers valuable insights to assist agricultural producers in making subsequent decisions. Full article

Chitosan nanoparticles (Ch NPs) are versatile nanomaterials with expanding agricultural and biomedical applications, highlighting the need for reproducible, low-cost, and scalable synthesis methods to ensure their safe and widespread use in biological systems. This study presents a simple ionic-gelation protocol using a serological pipette–needle dropwise system that minimizes reagent waste and requires no sophisticated equipment. The synthesized Ch NPs were characterized by UV–Vis spectroscopy, ESEM, TEM, EDS, DLS, XRD, and FTIR, confirming nanoscale size, strong positive surface charge, and characteristic chitosan–TPP interactions. To establish a standardized biological safety assessment framework, three representative bioassays were implemented across microbial, plant, and mammalian systems. Antibacterial testing against Xanthomonas oryzae pv. oryzae (Xoo) using a resazurin-based microdilution assay revealed a minimum inhibitory concentration (MIC) of 128 µg/mL, whereas bulk chitosan showed no inhibition up to 512 µg/mL. Phytotoxicity and seed germination assays on rice (Oryza ‘KDML105’) demonstrated no inhibitory effects on germination, with over 90% germination by day 3 and significantly enhanced seedling growth parameters (p < 0.05) at 64–128 µg/mL, indicating non-phytotoxicity. MTT assays confirmed that Ch NPs were non-toxic to both human skin cell lines (HDF and HaCaT) across 2.5–160 µg/mL, showing enhanced cell viability in HDF cells at specific concentrations and stable viability in HaCaT cells, indicating overall biocompatibility. Importantly, all bioassays were conducted under aligned concentration ranges to enable cross-system comparison and reproducibility. This integrated workflow links nanoparticle synthesis with a standardized, multi-system evaluation strategy, supporting the safe application of Ch NPs in biological systems. Full article

Invasive plant species are increasingly recognized not only as ecological threats but also as potential sources of bioactive compounds with agricultural applications. However, the combined allelopathic and insecticidal potential of Ailanthus altissima’s different plant parts remains insufficiently explored. This study evaluated the bioactivity of different plant part (leaf, bark, and branch) extracts of A. altissima. Secondary metabolites were characterized by HPLC–DAD–MS, while ethanol extracts (0.5–5%) were tested on wheat (Triticum aestivum) seed germination, seedling growth, oxidative status, and on the survival and repellency of the rice weevil (Sitophilus oryzae). Biological responses were strongly plant part and concentration-dependent. Leaf extracts contained the highest phenolic levels, dominated by caffeoylquinic acids and quercetin derivatives, whereas bark and branch extracts showed lower but compositionally distinct profiles. Despite this, bark and branch extracts produced the strongest biological effects, inhibiting germination energy and root growth at higher concentrations, while leaf extracts stimulated seedling performance, including increased vigor index, while in insect bioassays, bark and branch extracts caused higher mortality and stronger suppression of rice weevil populations. This study provides new evidence that biomass extracts of the invasive species A. altissima represent a promising source of biologically active compounds with both allelopathic and insecticidal properties, highlighting its potential valorization as a plant-based biopesticide for sustainable pest management. Full article

A comprehensive management framework integrating environmental and agronomic factors is critical for stable and resource-efficient rice production. The primary objective of this study was to develop an optimization framework for transplanted rice in Jiangsu Province, China, using a Generalized Additive Model (GAM). The framework was used to quantify the inter-annual stability of optimized management schemes and assess their sensitivity to future climate scenarios. The study evaluated the model’s generalization capability using two cross-validation strategies: Leave-One-Year-Out (LOYO) and Leave-One-Site-Out (LOSO). By predicting the yield of each candidate, the scheme maximizing yield was selected as the annual optimal management practice. Validation results demonstrated robust generalization capabilities across both spatial and temporal dimensions, with the model achieving an R² of 0.66 and an RMSE of 836 kg ha⁻¹ in LOSO validation, and an R² of 0.61 and an RMSE of 848 kg ha⁻¹ in LOYO validation. Analysis of the optimized schemes revealed that transplanting date and seedling age functioned as relatively stable planning benchmarks across years, whereas inter-annual adaptation was achieved primarily through adjustments in planting density and nitrogen inputs. Beyond yield prediction alone, this framework translates interpretable GAM response surfaces into spatially differentiated management prescriptions and highlights both soil-conditioned variable-rate strategies and the distinction between stable and adaptive management components under future climate scenarios. Full article