【Objective】Wheat starch mainly consists of amylose and amylopectin. Long-term consumption of refined flour products increases the risk of chronic diseases such as diabetes, whereas consuming flour with a high content of resistant starch has a positive effect on regulating blood glucose levels. Given the generally positive correlation between resistant starch and amylose, increasing the amylose content in wheat germplasm has become a goal for quality improvement breeding research. 【Method】Four gene fragments of starch branching enzyme (TaSBEIIb) were selected to successfully construct a high-efficiency dsRNA expression vector. A gradient optimization based on culture medium components significantly enhanced dsRNA yield. Based on this, the effects of naked dsRNA and dsRNA encapsulated with the nanocarrier hydroxypropyltrimethyl ammonium chitosan chloride (HACC) on wheat starch metabolism were explored through foliar spraying. Utilizing a wheat seedling culture system, the impact of dsRNA spraying on the amylose content in wheat seedlings and the expression of starch-related genes was observed. Furthermore, a field trial analyzed the effects of dsRNA spraying on the amylose content in mature wheat grains. The protective effect of chitosan quaternary ammonium salt-coated dsRNA and its influence on amylose content in mature wheat grains were also investigated. 【Result】Four recombinant plasmids (pRNAI-TaSBE1-pRNAI-TaSBE4), expressing dsRNA were successfully constructed. The optimized fermentation medium increased the dsRNA yield from 26.54 mg·L-1 to 50.65 mg·L-1, representing a 91% increase compared to the initial medium. Spraying dsRNA interfered with the expression of the target genes, with the highest interference efficiency observed on day 7 for the TaSBEIIb1 fragment. After interference with the four fragments, the expression of TaSBEIIb was reduced by an average of 47.73%. Additionally, the interference of TaSBEIIb affected the expression of other genes in the starch synthesis pathway, including TaSSII, TaSSIV, and TaSBEIIa1 with peak interference efficiencies occurring on days 3, 7, and 3, respectively. Their expression levels decreased by an average of 54.53%, 59.94%, and 47.64%. The 2023 field trial indicated that spraying naked dsRNA increased the amylose content in wheat grains by 17.2%-36.5% after 7 days of treatment, although the effect diminished to 0.2%-8.3% by the maturity stage. In the 2024 field trial, multiple applications of both naked dsRNA and chitosan quaternary ammonium salt-coated raised the amylose content in mature wheat grains from 27.72% to 30.37%, about 10% increase compared to the control. 【Conclusion】Exogenous spraying of TaSBEIIbs-dsRNA effectively increases the amylose content in starch.
【Objective】DUS (Distinctness, Uniformity, and Stability) testing provides important technical data for cotton variety approval and intellectual property protection, while the selection of similar varieties is a critical step in the process. Based on the revision of “NY/T 2469-2013, Protocol for the identification of cotton variety-SSR marker method”, this study aims further to construct a DNA fingerprint database for known upland cotton varieties for DUS testing in China and determine a genetic similarity threshold for rigorous and precise similar variety selection. 【Method】 Firstly, preliminary screening and subsequent re-screening were conducted on both the SSR primers from NY/T 2469-2013, and newly collected ones to identify a set of primers with stable PCR amplification, high polymorphism and clear peak patterns, replacing the original SSR primer set in the standard. Secondly, the selected SSR primers were employed to genotype the known cotton varieties to construct a DNA fingerprint database for those varieties. Finally, relationships between phenotypic and genetic differences of cotton varieties were investigated and a genetic similarity threshold for similar variety selection was determined. 【Result】 42 pairs of SSR primers covering all 26 chromosomes of upland cotton were selected, including 12 markers from the original standard. Among the selected 42 pairs of primers, 25 pairs amplified two loci, of which 23 revealed only one polymorphic locus, while the remaining two primer pairs (NAU1167 and HAU1413) had both loci showing polymorphism. A total of 164 alleles were detected from the 44 polymorphic loci, with the number of alleles at each locus ranging from 2 to 7. The polymorphism information content (PIC) of the loci varied from 0.15 to 0.66. 2 100 cotton varieties were genotyped using these primers. A DNA fingerprint database of known cotton varieties was constructed with a data integrity of 98.85%. Pairwise comparisons using the DNA data of 648 protected varieties, 843 approved varieties and 2 100 known upland cotton varieties revealed the distribution patterns of genetic differences between varieties among the three categories. More than 90.00% of comparisons in each category were concentrated in the range of 40.00%-70.00%. The proportion of variety pairs with genetic similarity exceeding 80.00% was 0.28%, 0.31% and 0.31% for the protected, approved and known varieties, respectively. Relationship analysis was conducted between phenotypic and genetic differences for 177 upland cotton varieties and their corresponding similar varieties. It was found that for the 54 cotton applications to which similar varieties with genetic similarity exceeding 90.00% existed, 18 (33.33%) failed to meet the distinctness requirement. In contrast, all 123 cotton applications with genetic similarity to their similar varieties below 90.00% could be clearly distinguished, exhibiting clear trait differences, thus fulfilling the distinctness criteria. The genetic similarity threshold for similar variety selection in upland cotton DUS testing based on these SSR markers could be set at 90.00%. For the variety pairs showing genetic similarity above this threshold, further field-based phenotypic evaluations are required. 【Conclusion】 In summary, NY/T 2469-2013, the standard for identifying upland cotton varieties using SSR markers, was revised. A DNA fingerprint database was constructed to support DUS testing of upland cotton in China. Furthermore, a genetic similarity threshold of 90.00% based on these SSR markers was established for selecting similar varieties, enhancing the precision and reliability of this process within DUS testing.
【Objective】The potato is a nutrient-rich and widespread non-grain crop that can be eaten as a staple food or vegetable. To reveal the influence of high temperature stress on the growth and development of potato seedlings, this study screened and identified small RNAs (miRNAs) and potential target genes that specifically respond to heat stress, providing a theoretical basis for research on the thermotolerance mechanism in potatoes. 【Method】The experimental material used in this study was 1-month-old tissue-cultured seedlings of Longshu 7, a potato variety independently bred by the Potato Research Institute, Gansu Academy of Agricultural Sciences. After incubation in plant growth chamber under normal temperature (17 ℃) and high temperature (28 ℃) for 10 days, samples were collected and subjected to small RNA sequencing (sRNA-seq) and transcriptome sequencing (RNA-seq). Based on high-quality sequencing data, we used bioinformatics methods to analyze and screen candidate miRNA-target gene pairs exhibiting negative regulatory relationships. In addition, real-time quantitative PCR (RT-qPCR) and dual luciferase assays (DLR) were used to validate some miRNA-target pairs. 【Result】Under high temperature stress, the abundance of 21 and 24 nt miRNAs in potato seedlings increased significantly, and the overall variation of all miRNA expression levels was 27.0% for PC1, while PC1 and PC2 accounted for 39.4% of the overall variation. According to miRNAs differential expression analysis, a total of 100 miRNAs were obtained, including 62 upregulated and 38 downregulated. Among the upregulated miRNAs, the fold change ranged from 1.02 to 6.94; while the fold change ranged from 1.01 to 7.11 in the downregulated miRNAs list. Transcriptome analysis showed that 579 differentially expressed genes were upregulated and 958 differentially expressed genes were downregulated in potato seedlings under high temperature stress. These genes were mainly involved in responding to biotic stress, external stress stimuli, and other cellular components and developmental processes. Integration of sRNA-seq and RNA-seq analyses revealed that a total of 13 miRNA-target pairs were obtained in the up-regulated miRNAs, while 5 miRNA-target gene pairs were obtained in the down-regulated miRNAs. Then, we selected three pairs of differentially expressed regulatory relationships (miRNA8051-Soltu.DM.10G026540, miRNA8051- Soltu.DM.10G026560, and miR5072-Soltu.DM.04G010170) for RT-qPCR. The results revealed that miRNAs showed opposite expression trends with their potential target genes, consistent with the results of bioinformatics analysis. In addition, we analyzed the regulatory pair of miRNA8051-Soltu.DM.10G026540 or Soltu.DM.10G026560 using DLR assay, confirming that miRNA8051 has a negative regulatory effect on both Soltu.DM.10G026540 and Soltu.DM.10G026560. 【Conclusion】It was revealed that potato seedlings under high temperature stress would regulate the target genes expression in a post-transcriptional regulatory manner, thus producing certain adaptations to the adverse environment. These candidate genes may be involved in biological processes such as transcription factors, wax synthesis and epigenetic regulation of methylation.
【Objective】The smallholder farming model has proven inadequate in meeting the demands of modern agricultural development, with large-scale planting emerging as a crucial pathway for agricultural modernization that facilitates sustainable agriculture development. This study aimed to investigate the current situation of wheat fertilization, irrigation, pest control, yield and economic benefits under different planting scales in Henan Province. Furthermore, it elucidated the impact of scale farming on wheat production, thereby providing a theoretical foundation and practical references for achieving sustainable wheat production. 【Method】A field investigation was conducted in Henan Province to examine the current situation of wheat production and its economic benefits from October 2023 to June 2024. By integrating yield with fertilizer use efficiency, this study systematically analyzed the variations in field management, wheat yield, fertilizer efficiency, and economic performance across different cultivation scales. 【Result】There were significant differences in wheat production among farmers with different cultivation scales. The majority of wheat cultivation areas in Henan Province fell within the range of 6.67-20.00 hm2, with the Zhengmai wheat series being the predominant cultivar. The most common seeding rate was 225 kg·hm-2. The application rates of nitrogen and phosphorus as basal fertilizers were lower in farms with 6.67-20.00 hm2 compared with other planting scales. Phosphorus and potassium applied during topdressing were also lower than that of other planting scales ≤33.33 hm2. Most surveyed farmers irrigated their fields three times, with the highest irrigation frequency observed in farms ranging from 20.00-33.33 hm2. Pesticide use primarily involved insecticides and fungicides, with the highest application frequencies for both observed in the 6.67-20.00 hm2 scale. Yields and partial factor productivity of fertilizers were significantly higher in farms sized 6.67-20.00 hm2 and 20.00-33.33 hm2 than in other scales. Wheat yields in these two groups were significantly increased by 3.57%-20.80%, and by 6.03%-23.67%, respectively, compared with other planting scales. Similarly, partial factor productivity improved by 15.87%-43.02%, and by 10.26%-36.10%, respectively. The output-input ratio was significantly higher in fields ≤6.67 hm2 compared with other scales, while the highest net returns were observed at farm sizes ≤33.33 hm2. 【Conclusion】Substantial variations in wheat management practices were observed across different farm scales in Henan Province. Comprehensive evaluation of yield, fertilizer partial factor productivity, net returns, and output-input ratio identified 6.67-33.33 hm2 as the optimal cultivation scale. Substantial efficiency gaps were observed among large-scale wheat growers, indicating considerable potential for optimization through improved management practices. The adoption of more efficient management measures could significantly enhance the operational efficiency of different planting scales.
【Objective】Root nodule senescence is a major factor limiting the symbiotic nitrogen fixation efficiency of leguminous crops. Delaying nodule senescence and prolonging its functional period is considered an effective strategy to improve crop yield and nutritional quality. To address the challenges of low nodulation efficiency, poor nitrogen fixation, and susceptibility to aflatoxin contamination in peanuts, our team has developed the ARC microbial agent, which effectively enhances nodulation while improving yield and quality. This study aims to elucidate the alleviating effects of the ARC microbial agent on peanut root nodules under dark stress, and to investigate its role in extending nodule lifespan and maintaining nitrogenase activity and functional stability. 【Method】A rapid senescence model was established by applying dark stress to peanut plants at the flowering and pegging stage. Root nodule phenotypic traits were dynamically extracted at different stress time points (0, 6, 12, 24, 36, 48, and 72 h) using the YOLOv8s algorithm, while nitrogenase activity was determined via the acetylene reduction assay. Based on both phenotypic and functional parameters, the regulatory effects of the ARC microbial agent on the rapid senescence of root nodules were comprehensively evaluated. 【Result】Compared with the control group, treatment with the ARC microbial agent significantly improved both the structural and functional traits of root nodules: the average diameter increased by 6.34%, and nitrogenase activity per gram increased by 117.11%. In addition, the average surface brightness and chroma of nodules increased by 6.32% and 3.05%, respectively. RGB color analysis further showed that nodules in the treatment group exhibited significantly higher color intensity across all channels, with mean increases of 6.32%, 8.06%, and 9.35% in the red, green, and blue channels, respectively, indicating a more vivid and brighter color appearance. During the dark stress-induced rapid senescence process, the ARC microbial agent effectively mitigated the decline in both nodule color phenotype and nitrogen fixation activity across different time points. In the early stress stage (0-6 h), the average brightness and chroma of control group nodules decreased by 8.36% and 16.85%, respectively, and nitrogenase activity dropped by 82.65%, indicating rapid onset of senescence. In contrast, nodules in the ARC treatment group showed only 1.26% and 11.31% decreases in brightness and chroma, respectively, with nitrogenase activity decreasing by 63.99%, reflecting a clear delay in early senescence and a strong protective effect. By the late stage of stress (72 h), the ARC treatment group exhibited brightness and chroma reductions of only 4.85% and 20.96%, significantly lower than the 13.82% and 23.15% declines observed in the control group, effectively alleviating the trend of color deterioration. At the same time, nitrogenase activity in the treatment group remained at 22.36% of its initial level, while nodules in the control group had already lost activity by 48 h, further confirming the sustained regulatory effect of ARC on nodule senescence. In addition, Pearson correlation analysis revealed that the red channel intensity was significantly positively correlated with nitrogenase activity (r=0.573, P=0.0003), while the green channel showed a weaker correlation and the blue channel showed no significant correlation. Notably, chroma, as a composite indicator of color variation, exhibited the strongest correlation with nitrogenase activity (r=0.736, P<0.001). Furthermore, with the progressive decline in nitrogenase activity, root nodules showed a gradual color transition from bright red to dark red and brown. 【Conclusion】The ARC microbial agent not only promotes peanut nodulation and nitrogen fixation, but also effectively delays the rapid senescence of root nodules induced by dark stress, thereby maintaining structural stability and sustaining nitrogen-fixing function. This contributes to enhanced symbiotic nitrogen fixation efficiency in leguminous crops. Moreover, nodule chroma was found to reflect changes in physiological activity and can serve as an early warning indicator of functional decline. These findings provide new perspectives and methodological support for advancing the study of nodulation and nitrogen fixation in legumes.
【Objective】This study aimed to elucidate the mechanisms by which exogenous brassinolide (BR) alleviates the inhibitory effects of sweet potato virus disease (SPVD) complex on storage roots germination in sweet potato, so as to provide the theoretical insights for mitigating SPVD impacts on sweet potato seedling production. 【Method】SPVD-infected ‘Jishu 25’ storage roots were subjected to seed soaking treatments with varying BR concentrations (0.1, 0.5 and 1.0 μmol·L-1) or brassinazole (BRZ, 0.1 μmol·L-1). Germination kinetics, soluble sugar content, antioxidant enzyme activities (SOD, POD and CAT), reactive oxygen species (ROS) accumulation, malondialdehyde (MDA) content, and expression levels of BR biosynthesis genes (CYP85A1 and CYP90D1) were quantified to characterize BR/BRZ-induced alterations in cellular redox homeostasis and transcriptional regulation. 【Result】SPVD significantly suppressed storage roots germination. 7 d, 14 d, and 28 d after seedling cultivation, the storage roots of sweet potato infected with SPVD germinate later, and the number and quality of seedlings were reduced. During germination initiation stage (7-14 d): Lower BR concentrations (0.1-0.5 μmol·L-1) enhanced quality of germination, elevated soluble sugar content, upregulated antioxidant enzyme activities, reduced ROS and MDA accumulation, and stimulated CYP85A1 and CYP90D1 expression. BRZ treatment exacerbated germination inhibition, suppressed antioxidant defenses, and increased oxidative damage. During the period of rapid germination (21-28 d), 0.1 μmol·L-1 BR sustained germination promotion, reduced soluble sugar content, maintained high antioxidant activity, minimized oxidative stress, and further amplified BR biosynthetic genes expression. BRZ consistently impaired germination, antioxidant capacity, and BR genes expression. 【Conclusion】The germination of sweet potato storage roots infected with SPVD was significantly inhibited. The appropriate concentration of BR (0.1 μmol·L-1) significantly alleviated the inhibition of SPVD on sweet potato storage roots germination by activating the antioxidant defense system, optimizing the dynamic balance of sugar metabolism, and enhancing the expression of endogenous BR synthesis genes.
【Objective】 To address the uncertainty in the extraction and dynamic monitoring of cropland cropping intensity (CI) caused by frequent cloud cover, fragmented farmland, and multi-cropping systems in southern China, this study aimed to fully leverage the advantages of multi-scale remote sensing observations to achieve efficient and accurate CI mapping for Hubei Province from 2000 to 2021, and to analyze the spatiotemporal evolution of regional agricultural production patterns. 【Method】 Time-series NDVI data from 250 m MODIS and 30 m Landsat were integrated using four representative spatiotemporal fusion algorithms: STARFM, ESTARFM, STNLFFM, and GF-SG. Fusion performance was comprehensively evaluated based on spectral fidelity (AD, RMSE) and spatial detail accuracy (Edge, LBP). The optimal algorithm was used to generate a 30 m/8-day NDVI dataset for 2000-2021. Cropland CI was extracted using a phenology-based peak detection method, and then its spatiotemporal variation was analyzed. 【Result】Compared with the other three spatiotemporal fusion algorithms, the GF-SG algorithm demonstrated the best performance in both spectral fidelity and spatial detail accuracy (|AD|<0.021, RMSE<0.111; |Edge|<0.55, |LBP|<0.10). The reconstructed NDVI time series using this algorithm improved the accuracy of cropland CI extraction by 0.02%-5.53%. Based on ground samples, the overall classification accuracy of cropland CI in Hubei Province reached 86.60%. From 2000 to 2021, approximately 20%-25% of croplands in the study area experienced CI transitions every five years, with the most significant changes occurring between 2005-2010 (25.79%) and the least between 2010-2015 (20.07%). The dominant transition type shifted from 'single-cropping to double-cropping' (13.49%) in the early years to 'double-cropping to single-cropping' (9.35%) and 'single-cropping to fallow' (4.90%) in the later years. 【Conclusion】Over the past two decades, Hubei Province has developed a diversified cultivation pattern dominated by single cropping, with coexistence of double cropping and fallow practices. The evolution of cropland CI has been jointly driven by policy guidance, labor force changes, resource input, and adjustments in cropping structure. By integrating multi-scale remote sensing data from MODIS and Landsat, this study constructed a high spatiotemporal resolution NDVI dataset, which enabled efficient and accurate extraction of long-term cropland CI in complex agricultural landscapes. The findings offered the critical support for agricultural production management and the development of cropland protection policies.
