Powdery Mildew Research Articles

Revisiting Golovinomyces Species (Erysiphaceae) in Korea: Re-identification, New Records, and Description of Golovinomyces physalidis sp. nov.

The genus Golovinomyces (Erysiphaceae, Ascomycota) comprises obligate biotrophic fungi responsible for powdery mildew diseases on many economically important and wild plant species, mainly within the Asteraceae. From 1987 to 2024, we collected about 1000 samples of Golovinomyces spp. across Korea and performed morphological observation along with multi-locus sequence analyses (including internal transcribed spacer, large subunit, intergenic spacer, and glyceraldehyde-3-phosphate dehydrogenase). Resolving five previous ambiguous species complexes, Golovinomyces ambrosiae, Golovinomyces artemisiae, Golovinomyces biocellatus, Golovinomyces cichoracearum, and Golovinomyces orontii, clarified species boundaries and refined previous identifications. As a result, this study identified 21 Golovinomyces species, representing an increase from 15 species previously recorded in Korea. A new species, Golovinomyces physalidis, was described as the causal agent of powdery mildew on Physaliastrum echinatum and Physalis alkekengi var. franchetii. Additionally, five species (Golovinomyces chrysanthemi, Golovinomyces latisporus, Golovinomyces monardae, Golovinomyces montagnei, and Golovinomyces riedlianus) and three host plants (Achillea ptarmica var. acuminata, P. echinatum, and Xanthium italicum) were newly documented in Korea. The present findings establish an updated taxonomic framework for Golovinomyces species, thereby improving identification accuracy and enhancing disease management.

First Report of Powdery Mildew Caused by Erysiphe pisi on Medicago ruthenica in Inner Mongolia, China.

Medicago ruthenica, a perennial forage species in the Leguminosae, is widely distributed in Northern China, Siberia and Mongolia. It is considered a high-quality protein source for livestock, and a valuable gene resource for alfalfa genetic improvement (Yin et al., 2021). However, M. ruthenica is susceptible to powdery mildew. In September 2021, an investigation of 500 m2 plant nursery at Inner Mongolia Agriculture University (111.73°E, 40.83°N), Hohhot, China, found that 90% leaves of M. ruthenica cv. Zhilixing were infected. Initially, small, white, and diffuse spots appeared on the adaxial leaf surface, then expanded to white mildew layer. Severely, orange or brown spots formed on the top of the layer, and abaxial leaf surface, stems and pods were also affected. The pathogen structures are as follows: conidia (n = 50) were produced singly, smooth, and elliptical or cylindrical, 19 to 38 × 10 to 18 µm, with a length/width ratio of 1.6 to 2.6; chasmothecia (n = 50) were black-brown, spherical, or subspherical, with a diameter of 75 to 130 μm. Approximately 17 colorless appendages may be contained in chasmothecia, whose average length was 50 μm. Chasmothecia contains 4 to 8 asci with 58 to 75 × 30 to 44 µm. The ascus contains 3 to 4 monospora and oval ascospores, 18 to 28 × 10 to 15 µm. Based on these morphological characteristics, the fungus was tentatively identified as an Erysiphe pisi (Ainsworth and Bisby, 1995; Hawksworth et al., 1995). For further confirmation, the internal transcribed spacer (ITS) and 28S large subunit (LSU) regions of one isolate (MNPM-MruZB1) were amplified using ITS4/ITS5 and NL1/TW14 primers (Innis et al., 1990; Takamatsu and Kano, 2001; Mori et al., 2000). Sequences of about 750 bp size were obtained and submitted to GenBank (accession number: PQ299565 and PV017896). They showed 99.70% (664/666) identity for ITS (KY661137.1) and 99.01% (808/816) for LSU (ON314806.1) with the previously reported sequences of E. pisi, respectively. Furthermore, the amplified sequences were used to construct a phylogenetic tree in MEGA7.0, which revealed the MNPM-MruZB1 isolate to be closely related to E. pisi. Pathogenicity tests were repeated three times on two-months old seedlings of three M. ruthenica varieties (Zhiling, Mengnong No.1 and Mengnong No.2). Three pots of healthy seedlings, from each variety, were inoculated by gently pressing diseased leaves, and the other three pots served as control inoculated with sterile distilled water. The seedlings were incubated at 21℃ and 70% relative humidity with a 16 h/8 h light/dark photoperiod. Seven days after inoculation, the three M. ruthenica varieties showed powdery mildew symptoms, while the control plants remained asymptomatic. Likewise, the results of morphology and sequence characteristics were also consistent with those of previous studies. E. pisi was identified as the causal species of powdery mildew of M. sativa and M. truncatula previously, whereas the pathogen of M. ruthenica powdery mildew is still unknown globally (Edmunds et al., 1998; Gupta et al., 2020). To the best of our knowledge, this is the first report of powdery mildew caused by E. pisi on M. ruthenica. It could serve as a basis for the identification, diagnosis, and prevention of M. ruthenica powdery mildew.

Влияние климатических факторов на развитие заболеваний дуба черешчатого (Quercus robur L.) на примере мучнистой росы

Powdery mildew is a fungal disease caused by the pathogen Erysiphe alphitoides and affects sweet oak (Quer-cus robur), a tree species found across a wide geographical region. The disease significantly impairs the physiological functions of affected trees, leading to a reduction in photosynthesis by up to 3.5 times and an increase in stomatal conductivity by 60%. This is particularly critical for mature oaks in urban areas. Our study aimed to investigate the relationship between climatic conditions, such as temperature, humidity, and precipitation, and the spread of powdery mildew in the Voronezh region's Upland Oak Groves. We focused on 80 ma-ture oak trees in areas with varying microclimates, using the method of spore collection on agar strips placed in the tree crowns. Climate data were recorded during the observational period. The findings revealed an increase in powdery mildew sporulation with rising temperatures above 22 °C and hu-midity between 70-80%. The highest concentration of conidia, reaching 92 spores/cm², was observed under favorable weather conditions. Our study underscores the crucial role of microclimate in the development of the disease, empha-sizing the need for tailored strategies in forest management. By employing the proposed data collection approach, we can lay the groundwork for proactive monitoring of sporulation patterns and early prediction of powdery mildew out-breaks, leveraging current climate information. In the long run, these findings contribute to sustainable oak forest management, mitigating the risk of forest degradation.

G143A Mutation Conferring Resistance to Quinone Outside Inhibitor Fungicides Detected in both Podosphaera xanthii and Erysiphe vignae Causing Powdery Mildew on Mung Bean (Vigna radiata) in Australia

Powdery mildew of mung bean (Vigna radiata) is caused by two species in Australia: Podosphaera xanthii and Erysiphe vignae. Currently, two fungicides are permitted for managing this disease in Australia: azoxystrobin and tebuconazole. The commercial fungicide products used for mung bean powdery mildew management contain either tebuconazole alone or a mixture of azoxystrobin and tebuconazole. This study detected the G143A mutation in the mitochondrial cytochrome b gene of both P. xanthii and E. vignae. The mutation was detected in two P. xanthii and one E. vignae populations out of a total of 15 populations sampled in south-east Queensland from 2017 to 2024. The G143A mutation is the major DNA marker of resistance to Quinone outside Inhibitor (QoI) fungicides, including azoxystrobin. This study confirmed that both powdery mildew species have developed QoI resistance in Australian mung bean fields.

Monitoring and predicting cotton leaf diseases using deep learning approaches and mathematical models

Cotton, the backbone of global textile production, demands sustainable agricultural practices to ensure fiber, food, and environmental security. Cotton crop play an essential role in farming economies; however, production is sometimes affected by various diseases that harm production. We proposed a methodology that uses formal modeling and verification for requirements confirmation to improve the monitoring and detection of cotton crop diseases. The correct information and requirements about disease symptoms can improve disease monitoring and prediction. The Temporal Logic of Action (TLA+) is used to construct a mathematical model to verify requirements by providing disease symptoms and then model checking to ensure correctness properties. Using model checking in TLA + ensures the reliability and correctness of disease symptom detection. We consequently used deep learning models to predict cotton diseases, i.e., Aphids, Armyworms, Bacterial Blight, Powdery Mildew, Target Spot, and Healthy leaf. Our results show that the Convolutional Neural Network (CNN) model achieved an overall accuracy of 98.7% with class-specific accuracy ranging from with F1-scores across all classes (e.g., 0.90 for Powdery Mildew and 0.87 for Army Worm).

Genetic analysis and identification of the candidate genes of maize resistance to Ustilago maydis by BSA-Seq and RNA-Seq

Maize common smut is a common disease caused by Ustilago maydis, can cause serious damage to the yield and quality of maize. To elucidate the genetic mechanism of resistance to maize smut disease, and to discover the relevant resistance genes, which have important scientific implications for maize resistance breeding. This study used the high-resistance maize variety Qi319 and the high-susceptibility variety Ye478 as materials, and constructed different segregating populations through hybridization, backcrossing, and other methods. Through field artificial inoculation and disease resistance identification, the six population (P1, P2, F1, F2, BC1P1, BC1P2) constructed was subjected to genetic and correlation analysis using a plant "quantitative trait main gene + multi gene mixed genetic model". The results showed that the optimal genetic model for maize resistance of U. maydis is MX2-ADI-ADI, the resistance of maize to U. maydis was mainly controlled by two pairs of additive-dominant-superior main genes + additive-dominant-superior polygenic genes. The heritabilities of major genes of F2, BC1P1 and BC1P2 were 69.24%, 57.89% and 54.09%, respectively, indicating that the resistance of the variety Qi319 to U. maydis was transmitted steadily to the progeny. The resistance/susceptibility pool was constructed from F2 population constructed by parents, a total of 6 candidate intervals were located on chromosomes 4, 6, 7 and 10, with a total length of 51.23Mb and containing 3723 genes by BSA-seq analysis. Transcriptome sequencing analysis showed that photosynthesis, plant pathogen interaction, carbon sequestration of photosynthetic organisms, plant hormone signal transduction, MAPK signal transduction and other pathways may be involved in the metabolic regulation of Qi319 resistance to U. maydis. The results laid a theoretical foundation for analyzing the molecular mechanism of maize resistance to powdery mildew and cloning the resistance gene.

Genotype by environment interaction analysis for resistance against powdery mildew and yellow rust in some promising exotic wheats

BackgroundPowdery mildew (PM), caused by Blumeria graminis f. sp. tritici, and yellow rust (YR), caused by Puccinia striiformis f. sp. tritici, constitute significant threats to wheat production, resulting in both qualitative and quantitative losses. Although fungicides can effectively manage these diseases, their application introduces environmental and health risks and foster the development of pathogen resistance. The development and implementation of wheat genotypes that exhibit resistance to PM and YR present a sustainable, cost-effective, and environmentally responsible alternative to chemical treatments.ResultsIn the present study, influence of environmental factors and genotype by-environment interaction (GEI) was evaluated on 142 wheat genotypes for PM and YR across four and three geographically diverse hotspot locations, respectively. The AMMI analysis of variance revealed that GEI and genotype (G) accounted for most of the variation observed for PM and YR. Twenty genotypes were moderately resistant to PM at seedling stage. Notably, ten genotypes demonstrated high resistance to PM, while 37 were identified as resistant to YR. Furthermore, 30 genotypes exhibited slow mildewing resistance to PM at the adult plant stage. The combined analysis utilizing AMMI and GGE biplots indicated that the genotypes Pollmer/CTY88.547, Syros, and Talent (Pm5 + ?) portrayed the highest level of combined resistance to both PM and YR across the evaluated locations. Additionally, the environments Kukumseri 2016 (E2 and En1) were the most effective for testing and selecting superior wheat genotypes for resistance to PM and YR, respectively.ConclusionIntegrating the strength of AMMI and GGE approaches enhances the accuracy of wheat genotype selection in multi- environment trials. Methods used showed strong agreement in identifying wheat genotypes resistant to PM and YR when facing diverse environmental factors.

First report of Podosphaera xanthii causing powdery mildew on Luffa cylindrica in China

First report of Podosphaera xanthii causing powdery mildew on Luffa cylindrica in China

Differential regulation of antioxidant machinery on grass pea partial resistance against powdery mildew and rust pathogens

Differential regulation of antioxidant machinery on grass pea partial resistance against powdery mildew and rust pathogens

Cytogenetic characterization of a novel wheat-rye 2R (2D) substitution line YT9 conferring powdery mildew resistance from the three-leaf stage and physical mapping of PmYT9.

A wheat-rye 2R (2D) substitution line with PmYT9 conferring powdery mildew resistance was characterized. PmYT9 was mapped to a 14. 55 Mb interval on 2RL. A homozygous translocation line carrying PmYT9 was developed. Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), poses a significant threat to wheat (Triticum aestivum L.) production. The identification and utilization of novel resistance genes from wheat relatives are an effective strategy for sustainable disease management. Rye (Secale cereale L. RR), a tertiary gene pool of wheat, harbors abundant genetic diversity. In this study, we developed a novel wheat-rye derivative line, YT9, by crossing hexaploid triticale 09R1-16 with wheat breeding line PB9. Genomic in situ hybridization (GISH), fluorescence in situ hybridization (FISH), and agronomic trait evaluations confirmed that YT9 was a stable 2R (2D) substitution and T1BL·1RS translocation line with favorable performance. Resistance phenotyping and microscopic observation of fungal growth revealed that YT9 exhibited resistance to Bgt from the three-leaf stage. Genetic analysis localized the resistance gene to chromosome arm 2RL of rye, designated PmYT9. To map PmYT9, 60Coγ-ray irradiation was employed to induce chromosomal structure variants. Integrated GISH, molecular marker analysis, and disease response assessment delimited PmYT9 to a 14.55Mb interval (831.45-846.00Mb) on the Lo7 rye reference genome, flanked by markers SW11163 and X2RL78. Additionally, a homozygous T7DS·7DL-2RL translocation line carrying PmYT9 was developed. This study expands the genetic diversity of wheat powdery mildew resistance, provides elite germplasm for wheat resistance breeding, and establishes a foundation for the molecular cloning of PmYT9.

An improved efficientnet-B5 for cucurbit leaf identification

Plant diseases significantly impact the quality and productivity of crops, leading to substantial economic losses. This paper introduces two enhanced EfficientNet-B5 architectures, EfficientNetB5-sigca and EfficientNetB5- sigbi, specifically designed to detect and classify diseases in cucurbit leaves. We employ EfficientNet-B5 for feature extraction, using a 456×456×3 input and omitting the top layer to generate feature maps with Swish activation. A global average pooling 2D layer replaces the conventional fully connected layer, producing a flattened vector. This is followed by a dense layer with four output units, L2 regularization, and sigmoid activation, using either categorical or binary cross-entropy as the loss function. We also developed a novel image dataset targeting cucumber and cantaloupe leaves, including 11,425 augmented images categorized into four disease classes: anthracnose, powdery mildew, downy mildew, and fresh leaf. Our experiments dataset demonstrates that the EfficientNetB5-sigbi achieves an accuracy of 97.07%, marking a significant improvement in classifying similar diseases in cucurbit leaves.

Taxonomic studies of powdery mildew fungi infecting almond and walnut in the Northwestern Himalayan region of India

Taxonomic studies of powdery mildew fungi infecting almond and walnut in the Northwestern Himalayan region of India

Molecular mechanism of the CmDSK2b-CmMLO5 module in regulating powdery mildew resistance in melon

Molecular mechanism of the CmDSK2b-CmMLO5 module in regulating powdery mildew resistance in melon

First report of powdery mildew caused by Erysiphe vaccinii on Eucalyptus camaldulensis in India

First report of powdery mildew caused by Erysiphe vaccinii on Eucalyptus camaldulensis in India

Exploring UAV narrow-band hyperspectral indices and crop functional traits derived from radiative transfer models to detect wheat powdery mildew

Exploring UAV narrow-band hyperspectral indices and crop functional traits derived from radiative transfer models to detect wheat powdery mildew

Activation of the phenylpropanoid pathway and enhanced powdery mildew resistance in honeysuckle induced by inactivated Erysiphe lonicerae spores

Activation of the phenylpropanoid pathway and enhanced powdery mildew resistance in honeysuckle induced by inactivated Erysiphe lonicerae spores

Evaluation of F2 Population in Bitter Gourd

An investigation of the F2 population of genotypes in bitter gourd (Momordica charantia L.)” was conducted during Kharif season 2023-24 at the Horticulture Research Scheme (Vegetable), Department of Horticulture, College of Agriculture, Parbhani, using a Randomized Block Design (RBD) with twenty treatments and two replications. Growth parameters like vine length and number of branches were recorded at the final harvest stage, with the maximum vine length observed in IC-085618 x Arka Harit (5.95 m) and the highest number of branches per vine in IC-085618 x Phule Green Gold (21.68). IC-085617 x CO-1 recorded the lowest node for first male flower appearance (12.36), while IC-085618 x Phule Green Gold showed the earliest male flower opening (37.47 days). Phule Hirkani had the lowest node for first female flower appearance (16.78), and IC-085618 x Konkan Tara showed the earliest female flower opening (46.44 days), 50% flowering (55.56 days), and first fruit harvest (58.11 days). IC-085618 x Phule Green Gold excelled with the highest number of female flowers per vine (69.99), fruits per vine (40.23), fruit yield per vine (3.92 kg), yield per hectare (24.86 q/ha), fruit length (19.43 cm), fruit weight (86.59 g), and longest duration to final harvest (137.18 days). IC-085617 x CO-1 had the highest fruit diameter (4.39 cm), and IC-505639 x CO-1 recorded the maximum flesh thickness (7.29 mm). Regarding quality, IC-085618 x Arka Harit was superior, showing the highest ascorbic acid content (113.43 mg/100g) and lowest incidence of Powdery mildew (10.57%) and Yellow mosaic virus (7.25%). Based on the results, IC-085618 x Phule Green Gold was identified as the most promising genotype for yield and fruit quality traits, while IC-085618 x Arka Harit was notable for superior nutritional quality and disease resistance.

Pesticide effects of highly stable green synthesized silver nanocomposites to be used in organic tomato crops

Greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae) together with the negative incidence of fungi such as Oidium neolycopersici and phytopathogenic bacteria, are responsible for causing serious economic losses in organic tomato crops. Silver nanoparticles (AgNPs) are a promising solution to problems caused by these pests due to their insecticidal and bactericidal properties. However, these compounds are unstable and tend to form agglomerates. This fact causes them to lose their properties so, preventing its use as an alternative to chemical pesticides in organic cultures. In this research, a novel one-step green synthesis method to obtain silver stable nanocomposites using rosemary extract (Rosmarinus officinalis L.) as green reducing agent was stablished. The polymer polyvinylpyrrolidone (PVP) was used additionally in the same synthesis reaction as AgNPs stabilizing agent. With this scalable one step synthesis, the obtained PVP-AgNPs nanocomposite showed particle sizes of 10.8 nm being highly stable during 326 days. At different assayed doses, this highly stable PVP-AgNPs nanocomposite, was able to control whitefly specimens efficiently with an average mortality rate of 98% after 10 days of the nanocomposite application to naturally infested tomato leaves grown under greenhouse conditions. Additionally, in a diffusion inhibition assay on agar plates, inhibition of Bacillus amyloliquefaciens, Pseudomonas syringae, and Xanthomonas sp growth was found. PVP-AgNPs nanocomposite was also effective to control Oidium neolycopersici in greenhouse grown tomato plants. To our knowledge, this is the first well-founded report related to a PVP-AgNPs nanocomposite obtained by green synthesis using rosemary extracts as reducing agent able to control whitefly and tomato powdery mildew, being a potential alternative to chemical pesticides in organic tomato crops.

CRISPR-Cas9 Technology: in Biotechnology a Breakthrough Innovation

CRISPR (clustered regularly interspaced short palindromic repeats)-Cas9 is a gene-editing technology based on regularly spaced short palindromic repeats that have revolutionized biotechnology research. This system offers the potential to edit desired changes and genes in the genome in a fast, inexpensive, simple way. Gene editing has many potential applications, including treating genetic diseases and the enhancement of yield and quality in agricultural products. The CRISPR-Cas9 system has a wide range of applications, from treating genetic diseases in medicine, improving crop yields in agriculture, obtaining disease-resistant animals, studying antibiotic resistance in microbiology, nitrogen fixation, biofuels, biosensors, greenhouse gas emissions, pesticide reduction, water management, etc. For example, this system has been used to successfully regulate mutations in intestinal organoids in the treatment of cystic fibrosis. In plants, successful results have been achieved in creating herbicide resistance in rice, powdery mildew in tomatoes, and reducing high amylopectin content in potatoes. In animals, studies are underway to provide resistance to bacteria that cause mastitis in cows. At the same time, research is underway to reduce milk allergens in goats by silencing the beta-lactoglobulin gene. However, the ethical aspects of CRISPR technology are also an important topic of debate. Given the potential risks and social implications of genetic engineering, ethical debates on this issue should continue. In conclusion, CRISPR-Cas9 is a revolutionary tool in genetic engineering and offers new opportunities for innovative applications in many fields. This article reviews studies on CRISPR-Cas9 technology, its use in medicine, agriculture, animal husbandry, and ethical debates.

First Report of Powdery Mildew Diseases on Field Pea (P. Sativum Linn) in Northern Guinea Savannah of Nigeria.

Pisum sativum (field pea) belongs to the family Fabaceae. It is one of the six major pulse crops cultivated globally and is second highest yielding legume. A survey was conducted in Northern guinea savanna of Nigeria to identify the causative fungi of powdery mildew diseases on field pea. Temporay slides were prepared in the field by placing a clear tape on the infected part of the plant sticky side down and the tape was placed on a drop of distilled water/lactophenol cotton blue on a slide then observed under the microscope. The size and shape of the conidia and conidiophore were recorded. Samples were then sent to the Commonwealth Agricultural Bureaux International (CABI), UK for confirmation of the identification for the fungi inducing the diseases. Results obtained from CABI showed that four different species of Erysiphe i.e. E. pisi, E. brunneopunctata. E. cruciferarum and E. cichoracearum were responsible for the powdery mildew diseases observed on P. sativum in the study areas. As an exotic plant, the fungi might have come along with the seeds into the country, as Erysiphe spp. is seed borne or other reservoir hosts of the fungi might have occurred in the wild. To the best of our knowledge, this is the first report of the four species of Erysiphe inducing powdery mildew diseases of field pea in Nigeria.