Search Results (245)

Biological control serves as a crucial strategy for crop disease management. The biocontrol potential and plant growth-promoting effects of the strain YTBTa14 were investigated. Genetic sequencing confirmed YTBTa14 as Pseudomonas chlororaphis, which exhibited broad-spectrum antifungal activity against multiple pathogens affecting grapevine, apple, cherry, and wheat. YTBTa14 significantly enhanced the growth of wheat and grapevine, specifically increasing wheat seed germination rates and improving root and coleoptile development. In grapevine plant, significant increases in root length, stem length, and fresh weight were observed. The strain demonstrated robust adaptability and stable antagonism under varying sodium chloride (NaCl) concentrations, pH levels, and temperatures. YTBTa14 modulated plant hormone levels, elevating the content of indole-3-acetic acid (IAA), gibberellins (GA), and cytokinins (CTK). Furthermore, it effectively stimulated the production of key plant defense enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). Pretreatment of grape leaves with YTBTa14 triggered plant cell defense response and upregulated the expression of defense-related genes PR1 (pathogenesis-related protein 1) and PAL1 (phenylalanine ammonia-lyase 1), thereby mitigating the severity of downy mildew disease and inducing systemic resistance. These findings demonstrate that YTBTa14 is a highly promising candidate for development as a multifunctional agricultural biocontrol agent. Full article

Grapevine (Vitis vinifera) is highly susceptible to fungal diseases, particularly downy mildew caused by Plasmopara viticola. Environmental contamination and potential health risks to viticulturists have raised concerns about the long-term sustainability of chemical control. In this study, we evaluated the potential of four biosurfactants—surfactin, rhamnolipid, sophorolipid, and spiculisporic acid—as alternative agents to chemical fungicides for disease management in viticulture. Surfactin, rhamnolipid, and sophorolipid, but not spiculisporic acid, significantly reduced the severity of grape downy mildew and strawberry anthracnose and induced the expression of defense-related genes, such as β-1,3-glucanase and class IV chitinase, in grapevine and strawberry leaves, although each biosurfactant triggered distinct gene expression patterns. Utilizing salicylic acid (SA)- and jasmonate (JA)-insensitive mutants of Arabidopsis thaliana, we found that sophorolipid induced plant resistance through the canonical SA signaling pathway. In contrast, plant resistance induced by surfactin and rhamnolipid was independent of both the SA and JA signaling pathways. Notably, sophorolipid was the only biosurfactant that induced systemic acquired resistance in grapevine leaves through unknown signaling pathways, suppressing P. viticola infection at sites distant from the treatment area. These findings suggest that biosurfactants, particularly sophorolipids, are a promising eco-friendly alternative to conventional fungicides in viticulture. Full article

Downy mildew, caused by the oomycete Pseudoperonospora cubensis, is the most destructive foliar disease of cucumbers. While partially resistant slicer cultivars (with spined fruits) are commercially available, no resistant Beit Alpha cultivars (characterized by smooth, dark green fruit) have been developed to date. Here, we report the successful breeding of downy mildew-resistant Beit Alpha cucumber lines. Resistance was transferred from the wild Sikkim cucumber accessions PI 197088 and PI 330628 (characterized by round fruit, with heavily netted brown rind). The resistance and fruit phenotype were restored through backcrosses to elite commercial susceptible cultivars. Due to the recessive nature of the resistance genes and their distribution across multiple chromosomes, the breeding program required multiple backcrosses and stringent selections for both resistance and fruit type. Full article

Downy mildew caused by Plasmopara viticola is an important disease in grape production, particularly in the highly susceptible, widely cultivated Vitis vinifera L. Breeding for disease resistance is an effective solution, and V. vinifera intraspecific crosses can yield progeny with both disease resistance and high quality. To assess the potential of intraspecific recurrent selection in V. vinifera (IRSV) in improving grapevine resistance to downy mildew and to analyze the pattern of disease resistance inheritance, the disease-resistant variety Ecolly was selected as one of the parents and crossed with Cabernet Sauvignon, Marselan, and Dunkelfelder, respectively, creating three reciprocal combinations, resulting in 1657 hybrid F1 progenies. The primary results are as follows: (1) significant differences in disease resistance among grape varieties and, significant differences in disease resistance between different vintages of the same variety were found; (2) the leaf downy mildew resistance levels of F1 progeny of different hybrid combinations conformed to a skewed normal distribution and showed some maternal dominance; (3) the degree of leaf bulbous elevation was negatively correlated with the level of leaf downy mildew resistance, and the correlation coefficient with the level of field resistance was higher; (4) five progenies with higher levels of both field and in vitro disease resistance were obtained. Intraspecific hybridization can improve the disease resistance of offspring through super-parent genetic effects, and Ecolly can be used as breeding material for recurrent hybridization to obtain highly resistant varieties. Full article

Grapevine breeding programs face difficulties in preserving germplasm, especially from species and interspecific hybrids, since most collections are maintained in the field and exposed to biotic and abiotic stress, which can lead to material loss. The Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF) Grapevine Breeding Program faces similar challenges, limiting studies on hybrids resistant to the nematode Pratylenchus brachyurus and downy mildew (Plasmopara viticola), which are valuable for genetic improvement. This study aimed to implement in vitro conservation under minimal growth conditions for interspecific hybrids of Vitis spp. from the UENF program. The protocol followed a completely randomized design in a 2 × 2 × 3 factorial scheme: two hybrids (CH1.2 and CH1.3), two temperatures (18 ± 1 °C and 27 ± 2 °C), and three sucrose concentrations (10, 20, and 30 g L⁻¹), over 180 days of in vitro culture. The results showed that conservation of the UENF hybrids is feasible using nodal segments as explants, at 18 ± 2 °C and 10 g L⁻¹ of sucrose, for up to four months. This protocol may also be applied to other Vitis spp., contributing to the preservation and continued study of valuable germplasm. Full article

Downy mildew, caused by Plasmopara viticola, is a major threat to grapevine (Vitis vinifera) cultivation in humid climates. Restrictions on synthetic pesticides and inconsistent efficacy of current biocontrol agents, especially under rainy conditions, complicate disease management. This study evaluated the potential of compost tea to suppress downy mildew in a two-year field experiment (2023 and 2024), combined with reduced synthetic fungicide applications. The study design compared two phytosanitary management strategies on a commercial vineyard: a conventional fungicide against a compost tea strategy supplemented with two cymoxanil applications. The experiment set up had three replicated blocks, each consisting of 100 plants for a total of 600 plants. Mechanistic insights were provided through controlled laboratory experiments involving pre- and post-infection leaf assays, vineyard bacteriome profiling, via 16S rRNA gene sequencing for bacterial communities, across vineyard compartments, i.e., bulk soil, rhizosphere, and phyllosphere, and grapevine metabolomic analysis by GC-MS analysis. Field trials demonstrated that compost tea combined with two fungicide applications effectively reduced disease severity, notably outperforming the fungicide alone in the particularly rainy year of 2023. Bacteriome analysis revealed that compost tea treatment enriched beneficial bacterial genera, including Pseudomonas, Sphingomonas, Enterobacter, Massilia, and Bacillus, known for their growth-promoting and biocontrol activity in the rhizosphere and phyllosphere. Laboratory assays on detached leaves further showed that compost tea alone could suppress both infection and sporulation of P. viticola. Metabolomic analysis highlighted the accumulation of compounds such as tartaric and shikimic acids in compost tea treated leaves, suggesting a potential role in induced resistance. The findings indicate that applying compost tea with reduced fungicide treatments represents a promising and sustainable strategy for managing grapevine downy mildew, even in challenging climates. Full article

Downy mildew is a highly destructive fungal disease that significantly reduces both the yield and quality of kimchi cabbage. Conventional detection methods rely on manual scouting, which is labor-intensive and prone to subjectivity. This study proposes an automated detection approach using RGB imagery acquired by an unmanned aerial vehicle (UAV), integrated with lightweight deep learning models for leaf-level identification of downy mildew. To improve disease feature extraction, Simple Linear Iterative Clustering (SLIC) segmentation was applied to the images. Among the evaluated models, Vision Transformer (ViT)-based architectures outperformed Convolutional Neural Network (CNN)-based models in terms of classification accuracy and generalization capability. For late-stage disease detection, DeiT-Tiny recorded the highest test accuracy (0.948) and macro F1-score (0.913), while MobileViT-S achieved the highest diseased recall (0.931). In early-stage detection, TinyViT-5M achieved the highest test accuracy (0.970) and macro F1-score (0.918); however, all models demonstrated reduced diseased recall under early-stage conditions, with DeiT-Tiny achieving the highest recall at 0.774. These findings underscore the challenges of identifying early symptoms using RGB imagery. Based on the classification results, prescription maps were generated to facilitate variable-rate pesticide application. Overall, this study demonstrates the potential of UAV-based RGB imaging for precision agriculture, while highlighting the importance of integrating multispectral data and utilizing domain adaptation techniques to enhance early-stage disease detection. Full article

Particle film technology is an environmentally sustainable crop protection method, offering an alternative to chemical pesticides for disease control. Copper-based compounds have long been central to the management of bacterial and fungal diseases, particularly in organic agriculture. However, due to their environmental persistence, their use has been increasingly restricted by European regulations, making the management of widespread diseases such as Olive Knot (Pseudomonas savastanoi pv. savastanoi) and Downy Mildew (Plasmopara viticola) more difficult. The LIFE Microfighter project addresses this problem by testing a novel Zeo-Biopesticide (ZBp), in which natural zeolite serves as a carrier for the beneficial bacterium Pseudomonas synxantha DLS65. Field trials conducted in high-rainfall areas of Emilia-Romagna (Italy) evaluated the product’s distribution and persistence on olive and grape leaves through ESEM (Environmental Scanning Electron Microscopy) observations, its ability to retain the microorganism, and its effectiveness for disease control. Results showed that ZBp significantly reduced Olive Knot incidence compared to both the untreated control and Cu-based treatments (p < 0.05), supporting its potential as an alternative for bacterial disease management, while showing no statistically significant difference compared to the control in either the incidence or severity of Downy Mildew (p > 0.05). Its persistence and adherence to plant surfaces, which could influence its overall field performance, were affected by environmental conditions, particularly rainfall. Full article

Light-harvesting chlorophyll a/b-binding (Lhc) proteins are integral membrane proteins that bind to pigment molecules, playing a critical role in photosynthetic processes, including light energy harvesting and transfer. To investigate the role of the Lhc gene family in cucumber (Cucumis sativus L), genome-wide identification of CsLhc gene family members and analysis of their regulatory networks were carried out using bioinformation and molecular biology research methods at Anhui Science and Technology University. The results indicated that the Lhc family consisted of 21 members, being categorized into five subfamilies: Lhca, Lhcb, CP24, CP26, and CP29. The gene structure and motifs within each subfamily are generally conserved. CsLhcs are distributed on seven chromosomes, including one pair of tandem duplicates and two pairs of segmental duplicates. Six CsLhcs exhibit eight linear relationships with seven AtLhcs, and one CsLhc shows a syntenic relationship with one OsLhc. Analysis of the cis-acting elements in CsLhc promoters revealed their potential involvement in stress responses. Transcriptome data indicated that CsLhcs are minimally expressed in male flowers and roots, but highly expressed in other organs. Analysis of stress response processes revealed that all Lhc genes participate in at least one stress response. Five Lhc genes were confirmed to appear to have expression change using qPCR analysis under high temperature and salt stress. Particularly, under downy mildew, root-knot nematode stresses, and blight stress, up-regulated Lhc genes were the most abundant ones, indicating that the Lhc family acts as a significant role in the growth and development of cucumber. These results provide valuable insights for further understanding the characteristics of the CsLhc family and analyzing the function of the Lhc family in cucumber resistance to biotic/abiotic stresses and in molecular breeding. Full article

Viticulture is facing challenges, like the impact of climate change and various pests and pathogens. Alongside powdery and downy mildew, black rot is one of the most prevalent fungal diseases in European wine-growing regions. The focus of grapevine breeding research has so far been mainly on resistance to mildew diseases, and marker-assisted selection (MAS) in breeding material is possible for the most important resistance loci. However, only a few loci have been described for black rot resistance and these cannot yet be used for MAS. Thus, the characterization of genetic resistance to black rot and the establishment of closely linked genetic markers is important for the breeding of cultivars with multifungal resistances. In this study, an improved SSR marker-based genetic map of the biparental mapping population V3125 (‘Schiava Grossa’ x ‘Riesling’) x ‘Börner‘ (Vitis riparia x Vitis cinerea) was used to perform QTL analysis for black rot resistance. A total of 195 F1 individuals were analyzed at 347 SSR marker positions distributed on all 19 chromosomes. QTL analysis detected two QTLs conferring resistance to black rot on linkage groups 14 (Rgb1) and 16 (Rgb2). Our results revealed for the first time that Rgb1 and Rgb2 are derived from the wild species V. riparia. The presence of both loci in F1 individuals showed a clear additive effect for black rot resistance, supporting the breeding strategy of pyramiding two or more resistance factors to achieve a stronger overall resistance. Full article

Bitter melon, an important medicinal and edible economic crop, is often threatened by diseases such as downy mildew, powdery mildew, viral diseases, anthracnose, and blight during its growth. Efficient and accurate disease detection is of significant importance for achieving sustainable disease management in bitter melon cultivation. To address the issues of weak generalization ability and high computational demands in existing deep learning models in complex field environments, this study proposes an improved lightweight YOLOv8-LSW model. The model incorporates the inverted bottleneck structure of LeYOLO-small to design the backbone network, utilizing depthwise separable convolutions and cross-stage feature reuse modules to achieve lightweight design, reducing the number of parameters while enhancing multi-scale feature extraction capabilities. It also integrates the ShuffleAttention mechanism, strengthening the feature response in lesion areas through channel shuffling and spatial attention dual pathways. Finally, WIoUv3 replaces the original loss function, optimizing lesion boundary regression based on a dynamic focusing mechanism. The results show that YOLOv8-LSW achieves a precision of 95.3%, recall of 94.3%, mAP50 of 98.1%, mAP50-95h of 95.6%, and F1-score of 94.80%, which represent improvements of 2.2%, 2.7%, 1.2%, 2.2%, and 2.46%, respectively, compared to the original YOLOv8n. The effectiveness of the improvements was verified through heatmap analysis and ablation experiments. The number of parameters and GFLOPS were reduced by 20.58% and 20.29%, respectively, with an FPS of 341.58. Comparison tests with various mainstream deep learning models also demonstrated that YOLO-LSW performs well in the bitter melon disease detection task. This research provides a technical solution with both lightweight design and strong generalization ability for real-time detection of bitter melon diseases in complex environments, which holds significant application value in promoting precision disease control in smart agriculture. Full article

This study examined the effectiveness of neem leaf extract (NLE) and azadirachtin (AZA) against two isolates of Plasmopara halstedii, which causes downy mildew in sunflowers. We also explored their physiological and histopathological effects. The pre-inoculation treatments included 10% and 20% NLE and 0.01% and 0.1% AZA, compared to a mefenoxam-treated control and a non-treated control. All treatments significantly reduced the disease rate compared to the inoculated controls (which had a 73–76% disease rate). The 10% NLE treatment showed the strongest effect against isolate 1 (0% damping-off), while the 20% NLE treatment was most effective against isolate 2 (4% damping-off). Neem treatments also significantly improved plant height; for instance, 20% of NLE-treated plants inoculated with isolate 2 reached approximately 15 cm, compared to about 8 cm in the inoculated controls. Histological analyses indicated limited hyphal spread and low levels of cortical necrosis in neem-treated plants, particularly with 0.1% AZA treatment. This suggests a moderate initial defense response without extensive hypersensitive cell death. Neem treatments were comparable to mefenoxam treatments. These results highlight the potential of neem-derived products, particularly 10% NLE and 0.1% AZA, for the integrated management of sunflower downy mildew through both direct pathogen suppression and enhanced host resistance. Full article

Downy mildew and powdery mildew are among the most serious diseases that affect grapevine. They can cause severe damage, such as yield loss, and affect the size of the grapes and their ability to accumulate sugars, affecting the flavor and aroma negatively and increasing the need for fungicidal sprays to combat these diseases and the pathogens that cause them. Clearly, it is important to predict these diseases early and apply treatment promptly to prevent and mitigate the effects of these diseases on crop production. This study presents a workflow in which IoT environmental sensors and machine learning methods are leveraged to accurately predict disease onset and allow for timely fungicide applications or other disease management strategies. We collected IoT grapevine field measurements and leveraged the records of the respective time periods during which fungicide treatments were applied to grapevine, and we used them to train and evaluate different ML tabular data classifiers as early predictors for each of the two diseases. The TabPFN transformer demonstrated superior performance in disease risk assessment while enabling real-time predictions with sub-second latencies, so it can be considered as a very good choice for a real-time grapevine disease prediction system. Full article

Downy mildew is among the most destructive diseases affecting grape production worldwide. It severely restricts the advancement of the grape industry. The causative pathogen, Plasmopara viticola, is an obligate biotrophic oomycete. Since the disease was introduced to Europe via grape cuttings in the 1870s, downy mildew has spread globally, resulting in devastating economic consequences. We review the current knowledge on the causative agent of grape downy mildew, its pathogenic mechanism, and control measures. Finally, we provide recommendations for developing more cost-effective strategies involving resistance genes and biocontrol agents to control grape downy mildew. Full article

The water status of plants is affected by abiotic and biotic environmental factors and influences the growth and yield formation of crops. Assessment of the leaf water content (LWC) of grapevine using hyperspectral imaging (1000–2500 nm) was investigated under controlled conditions for its potential to study the effects of the downy mildew pathogen Plasmopara viticola on LWC of host tissue in compatible and incompatible interactions. A calibration curve was established for the relationship between LWC and the Normalized Difference Leaf Water Index (NDLWI₁₉₃₇) that uses spectral information from the water absorption band and NIR for normalization. LWC was significantly lower for abaxial than for adaxial leaf sides, irrespective of grapevine genotype and health status. Reflecting details of leaf anatomy, vascular tissue exhibited effects reverse to intercostal areas. Effects of P. viticola on LWC coincided with the appearance of first sporangia on the abaxial side and increased during further pathogenesis. Continuous water loss ultimately resulted in tissue death, which progressed from the margins into central leaf areas. Tiny spots of brown leaf tissue related to the reaction of partial resistant cultivars could be monitored only at the sensor’s highest spatial resolution. Proximal sensing enabled an unprecedented spatial resolution of leaf water content in host–pathogen interactions and confirmed that resistance reactions may produce a combination of dead and still-living cells that enable the development of biotrophic P. viticola. Full article