Search Results (83)

The pathogenic fungus Mycocentrospora acerina, responsible for Panax notoginseng round spot disease, poses a serious threat to the development of the P. notoginseng industry. To investigate its genetic information and potential pathogenic mechanisms, this study employed nanopore third-generation sequencing technology to conduct de novo genome sequencing and analysis of M. acerina, followed by an assessment of its plant cell wall-degrading enzyme activities. The sequencing results revealed that the M. acerina genome has a total length of 37.03 Mb, a GC content of 47.68%, an N50 value of 1.66 Mb, and a repeat sequence proportion of 9.37%. A total of 9989 protein-coding genes were predicted. Genome annotation identified 499 carbohydrate-active enzyme (CAZyme) family genes—more than those found in Botrytis cinerea (469), Phanerochaete chrysosporium (381), and Erysiphe necator (136). Moreover, M. acerina harbors a relatively large number of genes encoding plant cell wall-degrading enzymes. Experimental measurements of cell wall-degrading enzyme activities were consistent with the genomic predictions, demonstrating that M. acerina exhibits strong abilities to degrade cellulose, pectin, and lignin. This study provides new insights into the pathogenic mechanisms of M. acerina and establishes a theoretical foundation for developing potential control strategies for P. notoginseng round spot disease. Full article

Biofungicide products are a rapidly expanding sector of the plant protection market. Powdery mildew of tomato (Solanum lycopersicum), caused by Erysiphe neolycopersici, can result in significant yield loss in high tunnel (HT) tomato production. Copper-based fungicides are heavily used in HTs, especially those in certified organic production, to control powdery mildew and other fungal diseases. Reliance on copper can lead to its overuse, subsequent resistance development in pathogens, and accumulation of high amounts of copper in the soil. In this study, we evaluated two bio-product alternatives to copper for efficacy against powdery mildew in an organic HT tomato production system over three growing seasons. These alternatives were a commercial biofungicide containing Bacillus subtilis GB03 and a filtered and unfiltered microbial fermentation product (F-MFP and UF-MFP, respectively). UF-MFP was a proprietary blend of yeast cell walls and inactive fermentation media, whereas F-MFP was processed to remove any particles larger than 0.2 μm. The HT-grown tomato plants were inoculated with E. neolycopersici (10⁴ conidia/mL) and three to five foliar applications of biofungicide were made per season. Powdery mildew severity was lower with MFPs compared to the water-treated inoculated treatment and B. subtilis, although this was not always statistically significant (p = 0.05). At assessment dates where statistically significant difference among treatments were observed, the MFP treatments were generally equivalent to the cuprous oxide standard. These results suggest that MFP may be a suitable alternative or alternation partner to copper-based products currently in use in HT tomato systems affected by powdery mildew. Full article

The development of grapevine varieties combining powdery mildew (Erysiphe necator) resistance with acceptable wine quality represents an important goal for sustainable viticulture. This study evaluated the oenological potential of five advanced breeding lines carrying Run1 or Run1Ren1 resistance loci, developed through marker-assisted selection to achieve 99.2–99.6% Vitis vinifera genome content. Genotypes were assessed under Chilean conditions during the 2024–2025 seasons, analyzing disease resistance, berry characteristics, and wine chemical parameters. All resistant genotypes exhibited complete powdery mildew resistance (OIV scores 9) without fungicide applications. Wine analyses showed pH 3.4–3.9, titratable acidity 3.7–7.8 g/L, and total phenolics 229.2–1356.1 mg GAE/L, values within ranges reported in the literature for commercial wines. Two genotypes evaluated across both seasons showed different patterns of year-to-year variation, with AJ-T2 showing 4.7% variation in anthocyanin content, while AJ-T6 exhibited greater variation in phenolic parameters. HPLC analysis revealed anthocyanin profiles dominated by malvidin-3-glucoside without diglucoside forms, consistent with V. vinifera patterns. These preliminary results from single-plant evaluations suggest that marker-assisted breeding may contribute to developing disease-resistant varieties with wine chemical parameters within commercial ranges, though multi-plant trials with appropriate controls are essential for validation. Full article

The basic helix–loop–helix (bHLH) transcription factors play a crucial role in plant development and stress resistance. Elucidating the structure and function of bHLH family members related to rubber tree powdery mildew (Erysiphe quercicola) is essential for breeding disease-resistant rubber tree varieties. In the rubber tree (Hevea brasiliensis Muell. Arg.) variety CATAS73397, 204 HbbHLH transcription factors were systematically identified at the genome level and classified into 15 subfamilies through evolutionary analysis. The expansion of this family was primarily driven by whole-genome duplication (WGD). Based on RNA-seq data from leaves infected with powdery mildew, 11 HbbHLH genes responsive to infection were identified. Phylogenetic analysis examined the evolutionary relationships between rubber tree bHLH genes and disease-resistant bHLH genes from other plants. Promoter analysis of the 11 differentially expressed genes revealed abundant cis-elements associated with light responses, hormones, and transcription factor binding. Quantitative Real-time polymerase chain reaction validation indicated that HbbHLH87 and HbbHLH162-2 were significantly downregulated during infection, whereas HbbHLH25 was significantly upregulated. These three genes exhibited strong responses to methyl jasmonate (MeJA) and salicylic acid (SA) treatments, suggesting their involvement in jasmonic acid and SA signal transduction pathways during the immune response. This study provides important insights into the molecular mechanisms underlying disease resistance in rubber trees and identifies potential targets for breeding disease-resistant varieties. Full article

Powdery mildew, caused by Erysiphe quercicola, is one of the primary diseases responsible for the reduction in natural rubber production in China. This disease is a typical airborne pathogen, characterized by its ability to spread via air currents and rapidly escalate into an epidemic under favorable environmental conditions. Accurate prediction and determination of the prevention and control period represent both a critical challenge and key focus area in managing rubber-tree powdery mildew. This study investigates the effects of spore concentration, environmental factors, and infection time on the progression of powdery mildew in rubber trees. By employing six distinct machine learning model construction methods, with the disease index of powdery mildew in rubber trees as the response variable and spore concentration, temperature, humidity, and infection time as predictive variables, a preliminary predictive model for the disease index of rubber-tree powdery mildew was developed. Results from indoor inoculation experiments indicate that spore concentration directly influences disease progression and severity. Higher spore concentrations lead to faster disease development and increased severity. The optimal relative humidity for powdery mildew development in rubber trees is 80% RH. At varying temperatures, the influence of humidity on the disease index differs across spore concentration, exhibiting distinct trends. Each model effectively simulates the progression of powdery mildew in rubber trees, with predicted values closely aligning with observed data. Among the models, the Kernel Ridge Regression (KRR) model demonstrates the highest accuracy, the R² values for the training set and test set were 0.978 and 0.964, respectively, while the RMSE values were 4.037 and 4.926, respectively. This research provides a robust technical foundation for reducing the labor intensity of traditional prediction methods and offers valuable insights for forecasting airborne forest diseases. Full article

Beneficial microorganisms are emerging as promising alternatives to conventional pesticides for the biological control of plant diseases. This study evaluated the efficacy of a consortium composed of Pseudomonas yamanorum and Trichoderma longibrachiatum and compost against three grapevine pathogens, Botrytis cinerea, Erysiphe necator, and Plasmopara viticola, in three cultivars: Victoria, Superior Seedless, and Early Sweet. The microbial consortium (P. yamanorum + T. longibrachiatum) combined with compost (treatment T4) significantly outperformed the individual treatments, reducing disease severity indices (DSIs) to 7.72, 5.35, and 3.37% in Victoria; 5.70, 6.95, and 3.32% in Superior Seedless; and 4.98, 2.35, and 2.84% in Early Sweet. The treatment also enhanced physiological traits, such as the chlorophyll content, and defense responses, including ascorbate peroxidase (APX), peroxidase (POX), and catalase (CAT) enzyme activities. Biochemical markers, including the total protein content, phenolic content, and reduced malondialdehyde (MDA) levels, indicated an improved oxidative stress tolerance. The soil analysis confirmed an increased pH, organic matter, nitrogen content, and microbial biomass. T4 further reduced the fruit disease incidence and improved quality attributes, including the sugar content and size, while lowering nitrate accumulation. These findings highlight the synergistic benefits of combining a microbial consortium with compost as a sustainable strategy to promote grapevine health, productivity, and soil resilience. Full article

Powdery mildew is a serious disease of the rubber tree (Hevea brasiliensis) worldwide. Temperature is the main climatic factor that influences the development of this disease. In this study, the effects of five high temperatures (30, 32, 34, 36, and 38 °C) at each of six exposure durations (0.5, 1, 3, 6, 12, and 24 h) were measured for the pathogen at 0, 3, 12, and 48 h post-inoculation (hpi), which represented four life stages of the fungus (conidia, conidial germination, infection, and hyphal growth). The results indicated that the germination, infection, and disease severity were reduced with increasing temperature and exposure duration. Temperature and exposure duration also significantly interacted to affect all life stages (p < 0.001). The relationships of the inhibition rate of conidial germination, infection, and disease severity with duration of exposure time (et) and high temperature (T) were described by logistic equations, with the percentage variance accounted for above 68%. Ungerminated conidia were found to be the most resistant to high temperature for E. quercicola from rubber tree, out of the four stages tested in this study. Only controlled-environmental experiments were conducted, and field studies are needed to enhance disease forecasting of rubber tree powdery mildew. Full article

The exocyst complex in eukaryotic cells modulates secretory vesicle transportation to promote exocytosis. The exocyst is also required for the hyphal growth and pathogenic development of several filamentous phytopathogens. Obligate biotrophic powdery mildew fungi cause considerable damage to many cash crops; however, the exocyst’s roles in this group of fungi is not well studied. To verify the functions of the exocyst in powdery mildew fungus, we identified two exocyst subunits, EqSec5 and EqSec6, from Erysiphe quercicola, a powdery mildew fungus that infects the rubber tree Hevea brasiliensis. When GFP-fused EqSec5 and EqSec6 were introduced into E. quercicola and another phytopathogenic fungus, Magnaporthe oryzae, they primarily localized to the hyphal tip region. Inducing gene silencing of EqSec5 or EqSec6 caused growth and infection defects, and those defects could not be fully restored under the NADPH oxidase inhibitor treatment to the plant. The silenced strains also induced the host defense response including reactive oxygen species accumulation and callose deposition. The silencing of EqSec5 or EqSec6 also inhibited the secretion of the effector protein EqIsc1, interrupting plant salicylic acid biosynthesis. Yeast two-hybrid and gene overexpression assays suggested that EqSec5 and EqSec6 interact with each other and can complement each other’s function during host infection. Overall, our study provides evidence that the exocyst in this powdery mildew fungus facilitates effector secretion, hyphal growth, and infection. Full article

The management of grapevine from diseases is now particularly focused on the development of environmentally friendly strategies. Although sulphur is not in itself a toxic substance, its extensive use in powdery mildew, in organic vineyards especially, may cause environmental problems and plant phytotoxicity and affect the health and safety of viticultural workers. The activity of sulphur applied at doses reduced up to 50% in tank mixtures with silicates or Equisetum arvense-based products was assessed on powdery mildew in grapevine. Two-year trials were carried out applying the products every 7–10 days in the period of greatest risk for disease infections, in two organic vineyards in the Abruzzo region, Italy. In both vineyards throughout all trial years, at harvest, disease incidence and severity on leaves and bunches in the silicon + sulphur treatments were generally significantly lower compared to both the sulphur at full dose and to the control. In all trials, in both vineyards, a strong activity of silicon + sulphur mixtures towards disease on leaves was observed. This effect could be decisive in lowering the potential inoculum in the following season. In the Ari vineyard, vines treated with the mixtures always increased yield quantity and quality, given the higher contents of soluble solids and lower levels of total acidity. In the Cellino vineyard, probably due to the young age of the vines, increases in yield quantity were observed, with lesser effects on quality. The promising activity of the mixtures needs further studies to confirm these positive results. Furthermore, in both vineyards, the source of primary inoculum of the pathogen was observed as chasmothecia on the leaves. Full article

Grapevine (Vitis vinifera L.) varieties are particularly susceptible to the pathogens downy mildew Plasmopara viticola and powdery mildew Erysiphe necator. Conventional methods for identifying and classifying spores rely on time-consuming microscopic examinations susceptible to human error and requiring qualified personnel. The aim of the present work has focused on the establishment of a protocol for the rapid molecular detection of the fungal species P. viticola and E. necator from adhesive tapes used to trap spores in airborne inoculum collector cyclones. Four DNA extraction methods were tested. Subsequently, molecular detection of both pathogens was performed by validating some of the specific molecular markers available in the literature. PCR with the primers Nad9 cob-F/Nad9 cob-R and Uncin144/Uncin511 showed specific results for P. viticola and E. necator, respectively, and the best results were obtained with the T-CTAB method. The methodology developed in this work could be of great help for relating direct measurement of P. viticola and E. necator airborne inoculum to disease risk and detection of pathogens, which could be integrated into the early diagnosis of these grapevine pathogens, improving existing warning systems such as Decision Support Systems. Full article

Powdery mildew and anthracnose are the main diseases of rubber trees. In recent years, there have been large outbreaks in the rubber-planting areas of Asia, seriously affecting the yield and quality of rubber latex. ZAR1 is a conserved and distinctive coiled-coil nucleotide-binding leucine-rich (CNL) repeat in the plant kingdom, playing a crucial role in disease-resistance processes. To elucidate the function of the HbZAR1 gene in rubber trees (Hevea brasiliensis), three candidate HbZAR1 genes were identified using bioinformatics methods and comprehensively analyzed. The results indicate that the HbZAR1 protein is conserved in different plant species. Examination of cis-regulatory element sequences of HbZAR1genes reveals that the HbZAR1 gene promoter exhibits a remarkable enrichment of stress, light, and hormone elements. An expression analysis shows that the expression levels of the three HbZAR1 genes are highest in the bark and lowest in latex. Three HbZAR1 genes can respond to both rubber tree Erysiphe quercicola and Colletotrichum siamense infection; especially, HbZAR1.1 and HbZAR1.2 show significant upregulation in expression levels during the early stages of infection. These findings suggest that the three HbZAR1 genes may be involved in rubber tree susceptibility to E. quercicola and C. siamense through different immune mechanisms. Subcellular localization results indicate that the HbZAR1 genes are expressed in the nucleus and plasma membrane. This study also shows that the three HbZAR1 genes and activated mutant HbZAR1.1^D481V do not induce stable ROS production and cell death, suggesting possible gene degradation, functional redundancy, or acting as minor genes in disease resistance. This research provides valuable insights for further studying the function of HbZAR1 genes in rubber trees and the mechanisms of immune molecules. Full article

This study investigated the technological parameters, microbiological, and functional properties of juice from Solaris grapes grown under conventional and organic farming systems to assess how these cultivation methods influence juice quality. The one-year study focused on key aspects such as the levels of health-promoting polyphenols, the presence of mycotoxins, and pesticide residues. Organic grapes showed greater bacterial and fungal diversity, with significant differences in dominant genera. Sphingomonas and Massilia were the predominant bacteria across both systems, while Erysiphe was more common in conventional grapes, and Aureobasidium was abundant in both. Despite the presence of genes for mycotoxin production, no mycotoxins were detected in the juice or pomace. Organic juice exhibited significantly higher levels of polyphenols, leading to enhanced antioxidant properties and improved technological characteristics, including lower acidity and higher nitrogen content. However, residues of sulfur and copper, used in organic farming, were detected in the juice, while conventional juice contained synthetic pesticide residues like cyprodinil and fludioxonil. These findings highlight that while organic juice offers better quality and safety in terms of polyphenol content and antioxidant activity, it also carries risks related to residues from organic treatments, and conventional juice poses risks due to synthetic pesticide contamination. Full article

PIWI, from the German word Pilzwiderstandsfähig, meaning “fungus-resistant”, refers to grapevine cultivars bred for resistance to fungal pathogens such as Erysiphe necator (the causal agent of powdery mildew) and Plasmopara viticola (the causal agent of downy mildew), two major diseases in viticulture. These varieties are typically developed through traditional breeding, often crossbreeding European Vitis vinifera with American or Asian species that carry natural disease resistance. This study investigates the transcriptional profiles of exocarp tissues in mature berries from four PIWI grapevine varieties compared to their elite parental counterparts using RNA-seq analysis. We performed RNA-seq on four PIWI varieties (two red and two white) and their noble parents to identify differential gene expression patterns. Comprehensive analyses, including Differential Gene Expression (DEGs), Gene Set Enrichment Analysis (GSEA), Weighted Gene Co-expression Network Analysis (WGCNA), and tau analysis, revealed distinct gene clusters and individual genes characterizing the transcriptional landscape of PIWI varieties. Differentially expressed genes indicated significant changes in pathways related to organic acid metabolism and membrane transport, potentially contributing to enhanced resilience. WGCNA and k-means clustering highlighted co-expression modules linked to PIWI genotypes and their unique tolerance profiles. Tau analysis identified genes uniquely expressed in specific genotypes, with several already known for their defense roles. These findings offer insights into the molecular mechanisms underlying grapevine resistance and suggest promising avenues for breeding strategies to enhance disease resistance and overall grape quality in viticulture. Full article

Glutaredoxins (GRXs) are widely distributed oxidoreductase enzymes that play important roles in plant growth, development, and responses to various stresses. In this study, bioinformatics methods were used to identify and analyze the wheat GRX gene family and predict their properties and potential functions. RNA-seq and RT-qPCR expression analyses were used to investigate their regulatory functions under hormone treatment and fungal diseases. In this study, 86 GRX genes were identified in wheat and classified into CC-type, CGFS-type, and CPYC-type categories with no TaGRX located on chromosome 4B. The results show that TaGRXs regulate wheat transcriptional responses and have an integrative role in biotic and abiotic stress responses. TaGRXs are involved in wheat responses to Fusarium graminearum, Puccinia striiformis, and Erysiphe graminis diseases. TaGRX73-7D, TaGRX20-3A, and TaGRX29-3B play a negative regulatory role in E. graminis infection but a positive regulatory role in F. graminearum and P. striiformis infection. These TaGRXs play potential regulatory functions in wheat responses to the plant hormones and signaling molecules, including IAA, ABA, H₂O₂, and SA. The findings of this study lay the groundwork for further investigation of the functions of wheat GRX genes and their potential use as candidate genes for molecular breeding of stress-resistant wheat varieties. Full article

The production of oak seedlings in intensive crops involves the modification of natural conditions, namely the degree of humidity, through artificial irrigation, which favors the appearance of the pathogen Erysiphe alphitoides, responsible for the Oak Powdery Mildew (OPM) disease. Thus, it is necessary to identify new substances and technologies to control OPM. In this sense, new products approved by the European Union (EU) and Forest Stewardship Council (FSC) were identified, both synthetic and, a great novelty, biological (based on chito-oligosaccharides-oligogalacturonans: COS-OGA). In order to quantify the results, a correlation was made with climatic factors, by sampling data related to temperature and relative humidity with Data Logger devices. The obtained results suggest that OPM has a high virulence in the temperature range of 20 to 30 °C; at a relative humidity above 75%. The data obtained from the field experiments show that the synthetic products controlled OPM with an effectiveness between 70% and 95%, and the biological product behaved almost similarly, between 60% and 90%, which creates high opportunities for environmentally friendly control of forest pathogens. Full article