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BACKGROUND: Stilbenoid extracts, such as those originating from grapevine by‐products (e.g. canes), are of interest for use as biopesticides in vineyard owing to their antimicrobial activities. However, stilbenoids are unstable in the environment, especially under light. This study aimed to chemically characterize the effect of UV light on stilbenoids present in a grapevine cane extract (CE), and to evaluate the antimicrobial activities against two major grapevine pathogens (Plasmopara viticola and Botrytis cinerea) of grapevine extracts exposed to UV. RESULTS: Treatment with UV (365 nm) on a grapevine CE led to degradation of stilbenoids (up to 71% after 1 h). The stilbenoid stability depended on their chemical structure: only those possessing CC, as trans‐resveratrol and trans‐ε‐viniferin, were affected with first their isomerization and secondly their oxidation/cyclization. As a consequence, UV‐exposed extracts (UV‐CEs) showed reduced antimicrobial activities against the two pathogens (mycelium and spores). For instance, regarding P. viticola, an UV‐CE exposed during 4 h showed an almost total loss of its activity on oomycete development and a 2.4‐fold inhibition of zoospore mobility in comparison to CE. For B. cinerea, the inhibition capacity of the same UV‐CE was reduced by only 1.1‐fold on mycelial development and by 3.2‐fold on conidial germination compared to CE. CONCLUSION: UV light triggered modifications on the structure of bioactive stilbenoids, resulting in losses of their antimicrobial activities. Photoprotection of stilbenoids has to be considered in the perspective of using them in vineyards as biopesticides. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Plasmopara viticola (Berk. & M. A. Curtis) Berl. & De Toni, the causal agent of downy mildew, affects both cultivated and wild grapevine. Wild species of the genus Vitis L. are reliable sources of resistance to many of the diseases that affect cultivated grapevines. For this reason, it is important to study wildly growing (typical wild and feral) accessions belonging to V. vinifera L. The aim of this research was to study the levels of resistance to P. viticola of 57 Georgian wildly growing grapevine accessions by leaf disc method. The data were collected over eight years, from 2014 to 2021. Different degrees of resistance have been detected, ranging from susceptible (8.8% of accessions), low resistance (8.8% of accessions) moderate resistance (22.8%), and resistance (12.3% of accessions). Resistance of the 33,3% of the tested accessions was unstable and varied from susceptible to resistance across the years. Among resistant wildly growing grapevine genotypes, there are several accessions with a high density of the trichomes, although the data showed that the density of prostrate and erect hairs of the leaves is not correlated with the resistance trait. A large number of resistant genotypes among wildly growing grapevines suggests that in its natural habitat more resistant forms to downy mildew survives in the process of natural selection. Further studies are needed to characterize the plant-pathogen interaction and the mechanism of resistance of the wild accessions, although the resistant accessions, such as Tedotsminda 07, Tedotsminda 09, Tedotsimda 10 can be interesting for the breeding purposes in the future. [ABSTRACT FROM AUTHOR]

Background: Cabbage (Brassica oleracea L. var. capitata) is an important crop within the Brassica oleracea species and is extensively cultivated worldwide. In recent years, outbreaks of downy mildew caused by Hyaloperonospora parasitica have resulted in substantial losses in cabbage production. Despite this, there have been limited studies on genes associated with resistance to downy mildew in cabbage. Results: This study identified sister lines exhibiting significant differences in disease resistance and susceptibility. Using bulked segregant analysis followed by sequencing (BSA-seq) and linkage analysis, the cabbage resistance locus BoDMR2 was accurately mapped to an approximately 300 kb interval on chromosome 7. Among the candidate genes identified, several single nucleotide polymorphisms (SNPs) and a 3-bp insertion were found within the conserved domain of the Bo7g117810 gene, encoding a leucine-rich repeat domain protein, in susceptible genotypes. Additionally, real-time quantitative polymerase chain reaction (RT‒qPCR) analysis revealed that the expression level of Bo7g117810 in resistant specimens was 2.5-fold higher than that in susceptible specimens. An insertion‒deletion (InDel) marker was designed based on the identified insertion in susceptible materials, facilitating the identification and selection of downy mildew-resistant cabbage cultivars. Conclusions: This study identifies Bo7g117810 as a potential candidate gene associated with adult-stage resistance to downy mildew in cabbage, supported by observed differences in gene sequence and expression levels. Furthermore, the development of an InDel marker I1-3, based on its mutation, provides valuable resources for breeding resistant cabbage cultivars. [ABSTRACT FROM AUTHOR]

The pathogen Plasmopara halstedii, causing downy mildew (DM), is a widespread sunflower disease which can be controlled by single dominant genes. Wild Helianthus annuus have been a valuable source of vertical resistance to control P. halstedii, but such resistance may eventually be overcome by new races of the pathogen. Alternatively, quantitative, or partial resistance, is more stable and may be combined with vertical resistance to prevent DM outbreaks. We assessed the responses of six populations of wild H. annuus naturalized in Argentina to race 710 of P. halstedii. We examined: 1) the aerial phenotype (including seedling death) using two damage scales and three disease indices, 2) the growth of the pathogen along the hypocotyls, and 3) the presence of the pathogen in the root system. We found that the evaluated sunflower wild populations had lower disease levels than the susceptible cultivated controls. A histologic analysis showed that the wild H. annuus seedlings showed cellular reactions (e.g. necrosis and the deposit of materials on the walls of invaded cells) to restrict the pathogen's growth, allowing the identification of two possible types of resistance: type I, when the growth of the pathogen was limited to the base of the hypocotyls, and type II, when the pathogen managed to invade the entire length of the hypocotyls. The wild sunflower populations also showed differential responses to root infections. A quantitative or partial genetic resistance, rather than resistance based on major genes, seems to be operating in the sampled populations. The individuals found to be resistant in each population represent promising germplasm for sunflower breeding. [ABSTRACT FROM AUTHOR]

Maize production and quality are affected by infection with plant pathogens. One of the maize's essential and main diseases is downy mildew caused by Peronosclerospora spp. Downy mildew is a limiting factor in increasing production and can reduce production by 80-100%. It is because the affected plant cannot produce cobs. Pathogens obtain nutrients from the host cell, which can kill the cell and damage the surrounding tissues, resulting in visible downy mildew symptoms. Boron (B) plays a role in forming phloem, increasing the fruit's number, weight, bunch weight, and diameter. The primary function of B at the molecular level is the cross-linking of pectin in the plant cell wall. Ramnogalacturonan II (RG II) is a pectic polysaccharide that contributes to the mechanical strength and properties of the primary wall cross-linked by borate diesters. Phosphorus (P) controls the downsides in the greenhouse and field conditions. This study aims to measure changes in chlorophyll index, P and B uptakes in downy mildew affected plants. The field experiment used a group randomized design with six natural phosphate (FA) application treatments and four groups of borax doses as replicates. The results showed that the downy mildew decreased the chlorophyll index of the leaves at different levels of attack. The results of P concentration according to the position of healthy plant leaves were significantly different due to P treatment. In contrast to concentration B, there is no real difference. P and B uptake results in downy mildew-infested plants showed a significant difference only in P uptake in leaves with 1 FA treatment. [ABSTRACT FROM AUTHOR]

Biotic stress leads to enormous yield, quality, and economic losses in grapevine (Vitis vinifera L.). However, the crucial genes and underlying mechanisms in grapevine response to biotic stress are still not fully understood. Therefore, a meta-analysis was done using microarray expression data from 114 samples from five biotic stress investigations to find differentially expressed genes (DEGs). Subsequently, 1005 DEGs yielded from the meta-analysis were subjected to further analysis using a combination of systems biology and machine learning algorithms. A total of 75 transcription factors (TFs) and 80 pathogen recognition genes (PRGs) were identified among the 1005 DEGs. The majority of upregulated PRGs belonged to a class of kinases (KIN), followed by the RLK, RLP, TRAN, N, and CK classes. Furthermore, the MYB and bHLH families had the highest number of up-regulated TFs in response to biotic stress. Their co-expression with biotic stress-related pathways highlights the crucial role of these families in the response to biotic stress in grapevine. Additionally, weighted gene co-expression network analysis identified six modules, three of which were upregulated and relevant to defense responses, photosynthesis process, and cell wall reinforcement. Using eight attribute weighting algorithms on the identified key genes, we prioritized eight genes with the highest relevance to both control and disease conditions. Our findings indicate that the transcriptome responses of grapevine plants to various biotic stimuli, including downy mildew, powdery mildew, grapevine leaf-roll-associated virus-3, and Bois noir phytoplasma, exhibit commonalities. These shared responses could serve as breeding targets for enhancing grapevine resistance to diverse biotic stresses. [ABSTRACT FROM AUTHOR]

Abstract Background Cabbage (Brassica oleracea L. var. capitata) is an important crop within the Brassica oleracea species and is extensively cultivated worldwide. In recent years, outbreaks of downy mildew caused by Hyaloperonospora parasitica have resulted in substantial losses in cabbage production. Despite this, there have been limited studies on genes associated with resistance to downy mildew in cabbage. Results This study identified sister lines exhibiting significant differences in disease resistance and susceptibility. Using bulked segregant analysis followed by sequencing (BSA-seq) and linkage analysis, the cabbage resistance locus BoDMR2 was accurately mapped to an approximately 300 kb interval on chromosome 7. Among the candidate genes identified, several single nucleotide polymorphisms (SNPs) and a 3-bp insertion were found within the conserved domain of the Bo7g117810 gene, encoding a leucine-rich repeat domain protein, in susceptible genotypes. Additionally, real-time quantitative polymerase chain reaction (RT‒qPCR) analysis revealed that the expression level of Bo7g117810 in resistant specimens was 2.5-fold higher than that in susceptible specimens. An insertion‒deletion (InDel) marker was designed based on the identified insertion in susceptible materials, facilitating the identification and selection of downy mildew-resistant cabbage cultivars. Conclusions This study identifies Bo7g117810 as a potential candidate gene associated with adult-stage resistance to downy mildew in cabbage, supported by observed differences in gene sequence and expression levels. Furthermore, the development of an InDel marker I1-3, based on its mutation, provides valuable resources for breeding resistant cabbage cultivars.

Abstract Background Spinach downy mildew, caused by the obligate oomycete pathogen, Peronospora effusa remains a major concern for spinach production. Disease control is predominantly based on development of resistant spinach cultivars. However, new races and novel isolates of the pathogen continue to emerge and overcome cultivar resistance. Currently there are 20 known races of P. effusa. Here we characterized the transcriptomes of spinach, Spinacia oleracea, and P. effusa during disease progression using the spinach cultivar Viroflay, the near isogenic lines NIL1 and NIL3, and P. effusa races, R13 and R19, at 24 h post inoculation and 6 days post inoculation. A total of 54 samples were collected and subjected to sequencing and transcriptomic analysis. Results Differentially expressed gene (DEG) analysis in resistant spinach interactions of R13-NIL1 and R19-NIL3 revealed spinach DEGs from protein kinase-like and P-loop containing families, which have roles in plant defense. The homologous plant defense genes included but were not limited to, receptor-like protein kinases (Spiol0281C06495, Spiol06Chr21559 and Spiol06Chr24027), a BAK1 homolog (Spiol0223C05961), genes with leucine rich repeat motifs (Spiol04Chr08771, Spiol04Chr01972, Spiol05Chr26812, Spiol04Chr11049, Spiol0084S08137, Spiol03Chr20299) and ABC-transporters (Spiol02Chr28975, Spiol06Chr22112, Spiol06Chr03998 and Spiol04Chr09723). Additionally, analysis of the expression of eight homologous to previously reported downy mildew resistance genes revealed that some are differentially expressed during resistant reactions but not during susceptible reactions. Examination of P. effusa gene expression during infection of susceptible cultivars identified expressed genes present in R19 or R13 including predicted RxLR and Crinkler effector genes that may be responsible for race-specific virulence on NIL1 or NIL3 spinach hosts, respectively. Conclusions These findings deliver foundational insight to gene expression in both spinach and P. effusa during susceptible and resistant interactions and provide a library of candidate genes for further exploration and functional analysis. Such resources will be beneficial to spinach breeding efforts for disease resistance in addition to better understanding the virulence mechanisms of this obligate pathogen.

In viticulture, pathogens like the oomycete Plasmopara viticola, the causal agent of downy mildew, can cause severe yield loss and require extensive application of plant protection chemicals. Breeders are generating pathogen-resistant varieties exploiting American and Asian wild Vitis germplasm as sources of resistance. Several loci mediating resistance to P. viticola have been identified in the past but may be overcome by specifically adapted strains of the pathogen. Aiming to find and characterize novel loci, a cross population with Vitis amurensis ancestry was investigated searching for resistance-correlated quantitative trait loci (QTL). As a prerequisite, a genetic map was generated by analyzing the 244 F1 individuals derived from a cross of the downy mildew susceptible Vitis vinifera cultivar 'Tigvoasa' and the resistant V. amurensis pBC1 breeding line We 90-06-12. This genetic map is based on the information from 627 molecular markers including 56 simple sequence repeats and 571 rhAmpSeq markers. A phenotypic characterization of the progeny showed a clear segregation of the resistance traits in the F1 population after an experimental inoculation of leaf discs with downy mildew. Combining genetic and phenotypic data, an analysis for QTL revealed a major locus on linkage Group 9 that correlates strongly with the resistance to downy mildew. The locus was mapped to a region of about 80 kb on the PN40024 (12x.V2) grapevine reference genome. This genomic region co-localizes with the formerly identified locus Rpv10 from the grapevine cultivar 'Solaris'. As we found different allele sizes of the locus-linked SSR markers than those characterizing the known Rpv10 locus and differences in the sequence of a candidate gene, it was regarded as a haplotype variant and named Rpv10.2. [ABSTRACT FROM AUTHOR]

Background: The purpose of applying bacterial consortium and rice husk charcoal to corn plants is to determine the effect of the combination and whether it can control the intensity of downy mildew attacks and increase corn plant growth. Methods: This research was conducted at the experimental farm of the University of Muhammadiyah Malang. This research was conducted using two factors: the dose of rice husk charcoal application and the application of bacterial consortium with three replications using a randomized block design. The treatments were Charcoal husk (H): H5 = Charcoal husk @5 tons/ha, H10= Charcoal husk @10 tons, H15 Charcoal husk @15 tons/ha, Bacterial consortium (W): W0= without bacteria, WL = bacterial consortium 10 cc/l via foliar spraying, WS = bacterial consortium 10 cc/l through soil, WLS = bacterial consortium 10cc/l through soil and foliar spraying Result: The results showed that the intensity of downy mildew attack on the combined application of the bacterial consortium and rice husk charcoal was lower than that of the no-combination treatment. The length and diameter of the plants that were treated with rice husk charcoal had a significant effect. Still, the application of the bacterial consortium had no effectand the number of leaves was not affected by the treatment. [ABSTRACT FROM AUTHOR]

Fungi infection, especially derived from Plasmopara viticola, causes severe grapevine economic losses worldwide. Despite the availability of chemical treatments, looking for eco-friendly ways to control Vitis vinifera infection is gaining much more attention. When a plant is infected, multiple disease-control molecular mechanisms are activated. PRRs (Pattern Recognition Receptors) and particularly RLKs (receptor-like kinases) take part in the first barrier of the immune system, and, as a consequence, the kinase signaling cascade is activated, resulting in an immune response. In this context, discovering new lectin-RLK (LecRLK) membrane-bounded proteins has emerged as a promising strategy. The genome-wide localization of potential LecRLKs involved in disease defense was reported in two grapevine varieties of great economic impact: Chardonnay and Pinot Noir. A total of 23 potential amino acid sequences were identified, exhibiting high-sequence homology and evolution related to tandem events. Based on the domain architecture, a carbohydrate specificity ligand assay was conducted with docking, revealing two sequences as candidates for specific Vitis vinifera–Plasmopara viticola host–pathogen interaction. This study confers a starting point for designing new effective antifungal treatments directed at LecRLK targets in Vitis vinifera. [ABSTRACT FROM AUTHOR]

Harpins play a key role in inducing disease resistance in crops, and identifying their core functional regions and establishing a system for their efficient expression would be very valuable. In this study, large amounts of soluble fusion proteins of harpin HrpZ and its subpeptides were obtained via the optimized induction conditions (28 ℃C with 0.5 mmol.L-1 IPTG for 6 h) in Escherichia coli BL21 (DE3). Hypersensitive response (HR) assays demonstrated that the C-terminal 66 aa of HrpZ (HrpZ_C_2_2) elicited a strong HR in tobacco (Nicotiana benthamiana) and grape (Flame Seedless) leaves. Additionally, treatment with HrpZ, and particularly HrpZ_C_2_2, significantly reduced the disease incidence and severity index of field vine leaves and those inoculated with downy mildew. The determination of the physiological parameters indicated that HrpZ, and especially HrpZ_C_2_2, improved the photosynthesis- and chlorophyll fluorescence-related parameters, enhanced the activity of defense-related enzymes, including SOD, POD, CAT and PAL, and increased the H2O2 level. Collectively, we efficiently expressed a core peptide of HrpZ and elucidated its strong ability to elicit a HR and resistance to downy mildew. This research provides insight into understanding the structure and function of HrpZ and will advance the application of HrpZ_C_2_2 to increase the resistance of grapevine to downy mildew. [ABSTRACT FROM AUTHOR]

Globally sustainable disease management ensuring high quality in grapes is in demand as it holds significant importance as a versatile fruit for consumption, winemaking, and production of various products such as grape juice, raisin, and grape‐seed oil. The present paper reports a combination of nano‐biotechnology as a promising strategy for enhancing plant health and fruit productivity in grapes combining Irradiated chitosan nanoparticles and bio‐control agents. The Irradiated Chitosan with Bacillus subtilis and Trichoderma viridae and pesticides were evaluated for disease management. Percent disease index, percent disease control, and percent yield enhancement in Cymoxanil 8% + Mamcozeb 64% WP @ 0.2% treatment were as 17. 24%, 67.97% and 33.91% in 150 ppm Irradiated chitosan+B. subtilis were 19.83, 63.16, 30.41 and in Trichoderma 150 ppm Irradiated chitosan were 24.58, 54.33, and 27.40, respectively as compared to untreated crop with disease severity 53.84% PDI. Thus, irradiated chitosan and Bacillus subtilis elucidated a synergistic combination for residue‐free efficient phytosanitary measures, which harnessed the strength of chitosan and bio‐control agents for sustainable grape productivity. These findings will also pave the way for a deeper understanding of the synergistic interaction between Irradiated nanochitosan and bio‐control agents for an eco‐friendly and economically viable disease management strategy. The minimum temperature and morning relative humidity (RH I) had positive significance, with correlation coefficients of 0.484 and 0.485, respectively. The evening relative humidity (RH II) had a positive highly significant positive correlation coefficient of 0.664. Chitosan merits as a multiple stress tolerance enhancing agent that will further help in mitigating climate change adaptations in grapevines reducing reliance on chemical agro‐inputs. [ABSTRACT FROM AUTHOR]

Peronospora is the largest genus of obligate biotrophic oomycetes, causing downy mildew disease on various cultivated and ornamental plants worldwide. Despite the known high host specificity in Peronospora, many host–pathogen combinations have not been thoroughly investigated with respect to their phylogenetic relationships. This is especially the case for groups in which only one species has been described on a host genus. In this study, we highlight the fact that Peronospora is still vastly underexplored by investigating 48 specimens of Peronospora parasitic on the ornamental plant genus Myosotis (Boraginaceae). Morphology and multigene phylogenetic relationships revealed six new Peronospora species parasitic on Myosotis, with one species parasitising the widely cultivated species Myosotis sylvatica, providing further evidence that Peronospora species are generally highly host-specific. As a consequence, Peronospora occurrences on the several hundred plant species that are not type host species for a described Peronospora species should be re-examined, as they might represent species overlooked in previous studies. [ABSTRACT FROM AUTHOR]

Downy mildew caused by Sclerospora graminicola is a systemic disease that affects the yield and quality of foxtail millet. This obligate biotrophic oomycete manipulates host physiology and immune processes through numerous effectors. A thorough comprehension of effector biology is crucial to unravel disease mechanisms and understand host plant resistance. In this study, bioinformatic analyses revealed 498 potentially secreted proteins in S. graminicola, of which 62 were identified as RXLR effectors; 46 RXLR‐encoding genes exhibited upregulated expression during the early stages of infection. To elucidate the functions of these secreted proteins, a heterogeneous expression system was developed using Nicotiana benthamiana. Twenty‐one RXLR effectors secreted by S. graminicola were transiently expressed in N. benthamiana, of which four could suppress INF1‐triggered cell death. Various defence responses in N. benthamiana were attenuated, including inhibition of defence gene expression, reduction of reactive oxygen species (ROS) accumulation and diminished callose deposition. The expression of SG_RXLR41 also enhanced the growth of Phytophthora capsici on N. benthamiana leaves. These findings indicate that S. graminicola facilitates infection and expansion through the secretion of multiple RXLR effectors, and SG_RXLR41 is an important virulence‐related effector that is involved in manipulating plant immunity by suppressing cell death. [ABSTRACT FROM AUTHOR]

BACKGROUND: Grapevine downy mildew, caused by Plasmopara viticola, is an economically important disease in Australia and worldwide. The application of fungicides is the main tool to control this disease. Frequent fungicide applications can lead to the selection of resistant P. viticola populations, which has negative impacts on the management of the disease. Identification of resistance and its prevalence is necessary to inform resistance management strategies. RESULTS: A total of 86 P. viticola isolates were collected between 2017 and 2022 from vineyards in 15 growing regions across Australia for four fungicide groups; phenylamide (PA, group 4), carboxylic acid amide (CAA, group 40), quinone outside inhibitor (QoI, group 11) and quinone outside inhibitor stigmatellin binding type (QoSI, group 45). Decreased phenotypic sensitivity was detected for all four groups, and resistance to metalaxyl‐M (PA) and pyraclostrobin (QoI), was detected. Genetic analysis to detect the G143A (QoI) and G1105S (CAA) mutations using amplicon‐based sequencing was performed for 239 and 65 isolates collected in 2014–2017 and 2017–2022, respectively. G143A was detected in 8% and 52% of isolates, respectively, with strong association to phenotypic resistance. However, G1105S was not detected in any isolates. CONCLUSION: Plasmopara viticola isolates in Australia with resistance to at least two fungicide groups have been detected, therefore it is necessary to adopt resistance management strategies where resistance has been detected. Vineyards should continue to be monitored to improve management strategies for downy mildew. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Downy mildew is one of the main diseases that cause a reduction in cucumber yield. Chemical control not only increases pathogenic bacteria resistance and causes environmental pollution but also endangers the health of humans as they are abundant pesticide residues in fruits. Dopamine, a strong antioxidant that widely exists in plants, can effectively protect plants from the adverse effects of such chemicals. In this study, the susceptible cucumber cultivar 'Changchun Mici' and the disease-resistant cultivar 'Jinchun No. 4' were used as test materials to explore the alleviating effect of exogenous dopamine on cucumber downy mildew. After downy mildew infection, exogenous dopamine (100 µmol L−1) had the greatest significant effect on improving the disease resistance of cucumber, increasing the activities of superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase in cucumber, thereby reducing the accumulation of the superoxide anion and hydrogen peroxide in leaves, the content of malondialdehyde, and the relative electrical conductivity in leaves, which significantly improved the antioxidant capacity of cucumber. Simultaneously, exogenous dopamine increased the leaf wax content and trichome density; the activities of polyphenol oxidase, chitinase, and β-1,3-glucanase; and the expression of CsPR1, so that the disease index was significantly reduced. As for nitrogen metabolism, exogenous dopamine significantly increased the activities of nitrate reductase, glutamine synthase, glutamate synthase, and glutamate dehydrogenase, as well as the content of nitrate nitrogen, whereas it decreased the accumulation of ammonium nitrogen, thereby promoting nitrogen metabolism in cucumber. As a consequence, exogenous dopamine improved the yield and quality of cucumbers infected by downy mildew. [ABSTRACT FROM AUTHOR]

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The application of copper-based fungicides has led to the problematic accumulation of copper in the soil of many European vineyards. In this work, we tested the effectiveness of downy mildew control strategies that considerably reduce the amount of copper, through the application of other non-toxic compounds. The study took place in three different regions of Catalonia, by combining smaller and larger-scale trials for two growing seasons. Although variations among experiments were detected, the treatments used here may reduce the applied copper content by up to 77 percent. The cooper reduction-strategies, which alternated standard copper application of copper oxychloride with applications of products based on Equisetum arvense L., or with applications of products with heptagluconic acid (an alternative formulation with a very low-rate of copper), provided the most consistent protection against downy mildew. Moreover, these treatments reduced copper inputs by 63 and 47 percent as compared to conventional treatments based on repeated applications of copper oxychloride. This work underlines the possibility of reducing the amount of copper applied to control downy mildew in Mediterranean vineyards, through the use of newly-developed formulations. [ABSTRACT FROM AUTHOR]

Grapevine downy mildew caused by Plasmopara viticola is a deleterious vine disease currently controlled using synthetic and copper-based fungicides. Environmental concerns surrounding such fungicides necessitate sustainable alternatives like grape cane extracts. However, studies into their efficacy and effects on the product remain limited. This study aimed to assess the open-field efficacy of a novel grape cane extract formulation, alone and combined with a copper agent, against downy mildew, and to examine its impact on berry and must composition. The results were compared to standard fungicides frequently used in integrated and organic viticulture. In 2022, the grape cane extract formulation reduced downy mildew severity by 78 % on berry clusters, comparable to the maximum acceptable dose of copper for organic farming in Germany (3 kg/ha/a). Combining the grape cane extract with the copper agent was more effective than the copper agent alone, but not more effective than the grape cane extract alone. In 2023, disease development was marginal, despite artificial inoculation. Compositional differences detectable by FTIR were insignificant between musts derived from all treatments, increased copper levels were observed whenever copper had been applied. The phenolic content in freeze-dried, de-seeded berries of 2022 was significantly lower after copper (14.6 mg/g dry weight DW) and grape cane extract treatments (6.6 mg/g DW) when compared to the control (36.1 mg/g DW), with discrepancies in stilbenoid and flavan-3-ol levels in particular, as analysed by HPLC-DAD. However, these differences were not confirmed in 2023, with results showing no correlations between different treatments and phenolic contents. These findings suggest that applications of the phenolic grape cane extract do not lead to artificially altered levels or relevant residues of the active constituents; i.e., the phenolic compounds in the product. In brief, grape cane extracts might represent a promising natural alternative to controlling grapevine downy mildew, particularly in organic viticulture, which, to date, heavily relies on (eco-)toxic copper-pesticides. Further multi-year studies including wine analyses are warranted to follow the entire flow towards the final product.

Elicitors can be used to reduce the application of conventional pesticides against grapevine diseases; however, they may disrupt plant primary metabolism. The long-term effects (more than 6 days after treatment) of applying plant defence stimulators (PDS) to protect grapevine from Plasmopara viticola were investigated. We studied the effect of three PDS (acibenzolar-S-methyl/ASM, potassium phosphonate/PHOS, methyl jasmonate/MeJA) and one surfactant (Triton) on gene expression and metabolite production in leaves of Vitis vinifera cv. Cabernet-Sauvignon before or after their inoculation with P. viticola. The molecular and biochemical results show the impact of these PDS on grapevine metabolism more than 6 days after treatment, and after inoculation. High-throughput q-RT-PCR revealed that sixty of the primary metabolism genes (ion homeostasis and hormones pathways) were modulated by all treatments, some modulations being specific to a given PDS. Meanwhile, 1H NMR studies revealed variations in metabolite abundances (amines, amino acids, organic acids, polyphenols and sugars), with some being common to all treatments (organic acid increase) and others specific to a single one. By combining two methodological approaches, it was possible to determine the specific effects of each PDS on Vitis. All PDS-induced resistance involved modulation of the primary metabolism. This innovative approach can be extended to vineyard studies in order to help better understand the variability of PDS effects in natura.

Abstract Background Aconitum carmichaelii Debx. has been widely used as a traditional medicinal herb for a long history in China. It is highly susceptible to various dangerous diseases during the cultivation process. Downy mildew is the most serious leaf disease of A. carmichaelii, affecting plant growth and ultimately leading to a reduction in yield. To better understand the response mechanism of A. carmichaelii leaves subjected to downy mildew, the contents of endogenous plant hormones as well as transcriptome sequencing were analyzed at five different infected stages. Results The content of 3-indoleacetic acid, abscisic acid, salicylic acid and jasmonic acid has changed significantly in A. carmichaelii leaves with the development of downy mildew, and related synthetic genes such as 9-cis-epoxycarotenoid dioxygenase and phenylalanine ammonia lyase were also significant for disease responses. The transcriptomic data indicated that the differentially expressed genes were primarily associated with plant hormone signal transduction, plant-pathogen interaction, the mitogen-activated protein kinase signaling pathway in plants, and phenylpropanoid biosynthesis. Many of these genes also showed potential functions for resisting downy mildew. Through weighted gene co-expression network analysis, the hub genes and genes that have high connectivity to them were identified, which could participate in plant immune responses. Conclusions In this study, we elucidated the response and potential genes of A. carmichaelii to downy mildew, and observed the changes of endogenous hormones content at different infection stages, so as to contribute to the further screening and identification of genes involved in the defense of downy mildew.

Abstract Oomycetes are filamentous organisms that resemble fungi in terms of morphology and life cycle, primarily due to convergent evolution. The success of pathogenic oomycetes lies in their ability to adapt and overcome host resistance, occasionally transitioning to new hosts. During plant infection, these organisms secrete effector proteins and other compounds during plant infection, as a molecular arsenal that contributes to their pathogenic success. Genomic sequencing, transcriptomic analysis, and proteomic studies have revealed highly diverse effector repertoires among different oomycete pathogens, highlighting their adaptability and evolution potential. The obligate biotrophic oomycete Plasmopara viticola affects grapevine plants (Vitis vinifera L.) causing the downy mildew disease, with significant economic impact. This disease is devastating in Europe, leading to substantial production losses. Even though Plasmopara viticola is a well-known pathogen, to date there are scarce reviews summarising pathogenicity, virulence, the genetics and molecular mechanisms of interaction with grapevine. This review aims to explore the current knowledge of the infection strategy, lifecycle, effector molecules, and pathogenicity of Plasmopara viticola. The recent sequencing of the Plasmopara viticola genome has provided new insights into understanding the infection strategies employed by this pathogen. Additionally, we will highlight the contributions of omics technologies in unravelling the ongoing evolution of this oomycete, including the first in-plant proteome analysis of the pathogen.

Field studies were carried out to evaluate valifenalate 6 % + mancozeb 60 % WG against downy mildew of cucumber incited by Pseudoperonospora cubensis. The results revealed that, application of valifenalate 6 % + mancozeb 60 % WG at 3000 g/ha had recorded lowest downy mildew severity (7.99%) with maximum yield of 12.23 t/ha which was significantly superior over standard check and untreated control. Therefore valifenalate 6 % + mancozeb 60 % WG can be an additional option for effective management of downy mildew of cucumber in order to break the fungicide resistance development by the pathogen against mancozeb. Subsequent testing on phytotoxicity revealed that there were no visual phytotoxic symptoms observed during the experimentation. [ABSTRACT FROM AUTHOR]

The genus Peronospora is the largest genus of the oomycetes, fungus-like members of the kingdom Straminipila that also contains amoeboid (e.g., Leukarachnion) and plant-like (e.g., Laminaria) lifeforms. Peronospora species are obligate biotrophic plant pathogens, causing high economic losses in various crops and ornamentals, including Plantago species. Several species of Plantago are used as speciality crops and medicinal plants. In this study, Peronospora species parasitic on Plantago were investigated based on morphology and phylogenetic analyses using two nuclear (ITS, nrLSU) loci and one mitochondrial (cox2) locus. As a result of these investigations, 10 new species are added to the already known Peronospora species on Plantago. Interestingly, it was found that four independent species are parasitic to Plantago major, highlighting that the reliance on the host plant for pathogen determination can be misleading in Peronospora. Taking this into account, morphological and phylogenetic analyses should be conducted as a prerequisite for effective quarantine regulations and phytosanitary measures. [ABSTRACT FROM AUTHOR]

Although irrigation scheduling has been studied for diverse vegetable crops, much less attention has been given to irrigation scheduling for the seed crops on which these production systems rely. In spinach, for which irrigation scheduling needs are likely to vary greatly between seed and leaf production, this leaves seed producers without adequate resources to make irrigation scheduling decisions. Our research sought to fill this gap by evaluating two alternative irrigation scheduling strategies (a publicly available decision-support tool and soil moisture sensors) and four soil moisture thresholds for irrigation for their impacts on vegetative growth, marketable seed yield, seed quality, and the severity of Stemphylium leaf spot (caused by Stemphylium vesicarium and Stemphylium beticola), a common foliar disease of spinach, under sprinkler irrigation. We found that in all 3 years of the study, earlier and more frequent irrigation increased vegetative growth. However, marketable seed yield only increased relative to the control treatment based on farmers' standard irrigation practices in 1 of the 3 years--a year with an abnormally late planting date. This indicates that vegetative growth is more responsive than seed yield to earlier and more frequent irrigation, and that increases in vegetative growth do not translate directly to increased marketable seed yield. Contrary to the expected increase in Stemphylium leaf spot severity with increasing irrigation, the severity decreased in both years it was measured, likely as a result of the small stature of the spinach seed parent lines used in our study and opportunistic pathogenicity on moisture-stressed plants. These results provide a useful foundation from which spinach seed producers can make irrigation management decisions for their crops that underpin a valuable global industry. [ABSTRACT FROM AUTHOR]

Downy mildew, a foliar disease caused by the oomycete Pseudoperonospora cubensis (Berk. and Curt.) Rostov, is one of the most destructive disease of cucumber (Cucumis sativus L.). Moderately resistant cultivars are available, but yield losses are high without the use of fungicides, therefore, higher levels of resistance are required to reduce the use of fungicides. Therefore, in the present study, 12 advance breeding lines along with susceptible check of cucumber were screened against downy mildew disease under natural field condition and artificial inoculation through seedling assay technique. The results confirmed that three lines namely IIHR-177-1-1-S7, IIHR-82-1-S6 and IIHR-81-1-S6 were found to be resistant with <10 per cent disease index (PDI) and significantly outperformed against check var. Swarna Agethi for yield and quality traits. These high yielding resistant lines can be utilized as one of the parents for the development of downy mildew resistant hybrids/varieties. [ABSTRACT FROM AUTHOR]

Both cucumber and melon are members of the Cucurbitaceae family and are important vegetable crops throughout the world. Among the most harmful oomycete species is downy mildew, which causes great damage to cucumber and melon production. An important basis for disease resistance molecular breeding is the study of genetic law and molecular regulation mechanism of cucumber and melon resistance to downy mildew. Pseudoperonospora cubensis is the pathogen responsible for downy mildew in cucumber and melon. Furthermore, there is a high degree of homology between the genomes of cucumber and melon. Cucumber and melon may therefore share a similar molecular genetic basis. This paper summarized and analyzed the physiological races differentiation of P. cubensis, the genetic law, and the mapping of resistance genes of cucumber and melon downy mildew resistance, to provide a reference for the comparative genomics research and the molecular design breeding of cucumber and melon downy mildew resistance. [ABSTRACT FROM AUTHOR]

Background: Aconitum carmichaelii Debx. has been widely used as a traditional medicinal herb for a long history in China. It is highly susceptible to various dangerous diseases during the cultivation process. Downy mildew is the most serious leaf disease of A. carmichaelii, affecting plant growth and ultimately leading to a reduction in yield. To better understand the response mechanism of A. carmichaelii leaves subjected to downy mildew, the contents of endogenous plant hormones as well as transcriptome sequencing were analyzed at five different infected stages. Results: The content of 3-indoleacetic acid, abscisic acid, salicylic acid and jasmonic acid has changed significantly in A. carmichaelii leaves with the development of downy mildew, and related synthetic genes such as 9-cis-epoxycarotenoid dioxygenase and phenylalanine ammonia lyase were also significant for disease responses. The transcriptomic data indicated that the differentially expressed genes were primarily associated with plant hormone signal transduction, plant-pathogen interaction, the mitogen-activated protein kinase signaling pathway in plants, and phenylpropanoid biosynthesis. Many of these genes also showed potential functions for resisting downy mildew. Through weighted gene co-expression network analysis, the hub genes and genes that have high connectivity to them were identified, which could participate in plant immune responses. Conclusions: In this study, we elucidated the response and potential genes of A. carmichaelii to downy mildew, and observed the changes of endogenous hormones content at different infection stages, so as to contribute to the further screening and identification of genes involved in the defense of downy mildew. [ABSTRACT FROM AUTHOR]

Oomycetes are filamentous organisms that resemble fungi in terms of morphology and life cycle, primarily due to convergent evolution. The success of pathogenic oomycetes lies in their ability to adapt and overcome host resistance, occasionally transitioning to new hosts. During plant infection, these organisms secrete effector proteins and other compounds during plant infection, as a molecular arsenal that contributes to their pathogenic success. Genomic sequencing, transcriptomic analysis, and proteomic studies have revealed highly diverse effector repertoires among different oomycete pathogens, highlighting their adaptability and evolution potential. The obligate biotrophic oomycete Plasmopara viticola affects grapevine plants (Vitis vinifera L.) causing the downy mildew disease, with significant economic impact. This disease is devastating in Europe, leading to substantial production losses. Even though Plasmopara viticola is a well-known pathogen, to date there are scarce reviews summarising pathogenicity, virulence, the genetics and molecular mechanisms of interaction with grapevine. This review aims to explore the current knowledge of the infection strategy, lifecycle, effector molecules, and pathogenicity of Plasmopara viticola. The recent sequencing of the Plasmopara viticola genome has provided new insights into understanding the infection strategies employed by this pathogen. Additionally, we will highlight the contributions of omics technologies in unravelling the ongoing evolution of this oomycete, including the first in-plant proteome analysis of the pathogen. [ABSTRACT FROM AUTHOR]

This paper focuses on the creation of an in vitro collection of grapevine hybrids from the breeding program of the Kazakh Scientific Research Institute of Fruit Growing and Viticulture and investigates the presence of Plasmopara viticola resistance mediated by Rpv3 and Rpv12 loci. We looked at the optimization of in vitro establishment using either shoots taken directly from field-grown plants or from budwood cuttings forced indoors. We further screened for the presence of endophyte contamination in the initiated explants and optimized the multiplication stage. Finally, the presence of the resistance loci against P. viticola was studied. The shoots initiated from the field-sourced explants were the more effective method of providing plant sources for in vitro initiation once all plant accessions met the goal of in vitro establishment. The concentration of phytohormones and the acidity of the culture medium have a great effect on the multiplication rate and the quality of in vitro stock cultures. Out of 17 grapevine accessions, 16 showed the presence of single or combined resistance loci against P. viticola. The grapevine accessions identified as carrying Rpv3 and Rpv12 alleles represent important genetic resources for disease resistance breeding programs. These accessions may further contribute to the creation of new elite cultivars of economic interest. [ABSTRACT FROM AUTHOR]

In viticulture, downy mildew is one of the most common diseases that, if not adequately treated, can diminish production yield. However, the uncontrolled use of pesticides to alleviate its occurrence can pose significant risks for farmers, consumers, and the environment. This paper presents a new framework for the early detection and estimation of the mildew's appearance in viticulture fields. The framework utilizes a protocol for the real-time acquisition of drones' high-resolution RGB images and a cloud-docker-based video or image inference process using object detection CNN models. The authors implemented their framework proposition using open-source tools and experimented with their proposed implementation on the debina grape variety in Zitsa, Greece, during downy mildew outbursts. The authors present evaluation results of deep learning Faster R-CNN object detection models trained on their downy mildew annotated dataset, using the different object classifiers of VGG16, ViTDet, MobileNetV3, EfficientNet, SqueezeNet, and ResNet. The authors compare Faster R-CNN and YOLO object detectors in terms of accuracy and speed. From their experimentation, the embedded device model ViTDet showed the worst accuracy results compared to the fast inferences of YOLOv8, while MobileNetV3 significantly outperformed YOLOv8 in terms of both accuracy and speed. Regarding cloud inferences, large ResNet models performed well in terms of accuracy, while YOLOv5 faster inferences presented significant object classification losses. [ABSTRACT FROM AUTHOR]

Downy mildews are major constraints on spinach and lettuce production globally. Disease management can be achieved with fungicides, but routine applications are costly and can lead to pathogen resistance. Detection of airborne spores could guide sustainable fungicide application, and, considering that spinach and lettuce are often grown in the same cycles, simultaneous detection of both pathogens is practical. Here, a multiplex hydrolysis probe quantitative PCR assay was designed using single copy mitochondrial DNA targets for spinach downy mildew (Peronospora effusa) and lettuce downy mildew (Bremia lactucae). To quantify P. effusa and B. lactucae sporangia, a standard curve was developed for each pathogen using the multiplex qPCR to amplify DNA obtained from known dilutions of sporangia. Analysis of these curves revealed a greater sensitivity for B. lactucae, indicating that the sporangia of B. lactucae may harbor more mitochondria than those of P. effusa, providing insight into the biology of these pathogens. The multiplex qPCR assay was partnered with two different spore trap types: a cyclone spore trap and an impaction spore trap. Results from air sampling revealed that the cyclone spore traps collect significantly more sporangia compared with impaction traps. Exposure of P. effusa sporangia to desiccation was performed to assess the environmental impact on the assay, and although detection levels were reduced, they were still apparent. This detection and quantification tool will be useful in efforts to improve the accuracy of downy mildew forecasting, which in return may reduce fungicide usage or improve its efficiency. [Figure: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 “No Rights Reserved” license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2024.

Downy mildew of grapevine (Vitis vinifera), caused by the oomycete Plasmopara viticola, is an important disease that is present in cultivation areas worldwide, and using resistant varieties provides an environmentally friendly alternative to fungicides. DOWNY MILDEW RESISTANT 6 (DMR6) from Arabidopsis is a negative regulator of plant immunity and its loss of function confers resistance to downy mildew. In grapevine, DMR6 is present in two copies, named VvDMR6-1 and VvDMR6-2. Here, we describe the editing of VvDMR6-1 in embryogenic calli using CRISPR/Cas9 and the regeneration of the edited plants. All edited plants were found to be biallelic and chimeric, and whilst they all showed reduced growth compared with non-transformed control plants, they also had reduced susceptibility to P. viticola. Comparison between mock-inoculated genotypes showed that all edited lines presented higher levels of salicylic acid than controls, and lines subjected to transformation presented higher levels of cis-resveratrol than controls. Our results identify VvDMR6-1 as a promising target for breeding grapevine cultivars with improved resistance to downy mildew. [ABSTRACT FROM AUTHOR]

Downy mildew caused by Hyaloperonospora brassicae is a severe disease in Brassica oleracea that significantly reduces crop yield and marketability. This study aims to evaluate different vegetation indices to assess different downy mildew infection levels in the Brassica variety Mildis using hyperspectral data. Artificial inoculation using H. brassicae sporangia suspension was conducted to induce different levels of downy mildew disease. Spectral measurements, spanning 350 nm to 1050 nm, were conducted on the leaves using an environmentally controlled setup, and the reflectance data were acquired and processed. The Successive Projections Algorithm (SPA) and signal sensitivity calculation were used to extract the most informative wavelengths that could be used to develop downy mildew indices (DMI). A total of 37 existing vegetation indices and three proposed DMIs were evaluated to indicate downy mildew (DM) infection levels. The results showed that the classification using a support vector machine achieved accuracies of 71.3%, 80.7%, and 85.3% for distinguishing healthy leaves from DM1 (early infection), DM2 (progressed infection), and DM3 (severe infection) leaves using the proposed downy mildew index. The proposed new downy mildew index potentially enables the development of an automated DM monitoring system and resistance profiling in Brassica breeding lines. [ABSTRACT FROM AUTHOR]

Melon (Cucumis melo L.) is a valuable horticultural crop of the Cucurbitaceae family. Downy mildew (DM), caused by Pseudoperonospora cubensis, is a significant inhibitor of the production and quality of melon. Brassinolide (BR) is a new type of phytohormone widely used in cultivation for its broad spectrum of resistance- and defense-mechanism-improving activity. In this study, we applied various exogenous treatments (0.5, 1.0, and 2.0 mg·L−1) of BR at four distinct time periods (6 h, 12 h, 24 h, and 48 h) and explored the impact of BR on physiological indices and the genetic regulation of melon seedling leaves infected by downy-mildew-induced stress. It was mainly observed that a 2.0 mg·L−1 BR concentration effectively promoted the enhanced photosynthetic activity of seedling leaves, and quantitative real-time polymerase chain reaction (qRT-PCR) analysis similarly exhibited an upregulated expression of the predicted regulatory genes of photosystem II (PSII) CmHCF136 (MELO3C023596.2) and CmPsbY (MELO3C010708.2), thus indicating the stability of the PSII reaction center. Furthermore, 2.0 mg·L−1 BR resulted in more photosynthetic pigments (nearly three times more than the chlorophyll contents (264.52%)) as compared to the control and other treatment groups and similarly upregulated the expression trend of the predicted key enzyme genes CmLHCP (MELO3C004214.2) and CmCHLP (MELO3C017176.2) involved in chlorophyll biosynthesis. Meanwhile, the maximum contents of soluble sugars and starch (186.95% and 164.28%) were also maintained, which were similarly triggered by the upregulated expression of the predicted genes CmGlgC (MELO3C006552.2), CmSPS (MELO3C020357.2), and CmPEPC (MELO3C018724.2), thereby maintaining osmotic adjustment and efficiency in eliminating reactive oxygen species. Overall, the exogenous 2.0 mg·L−1 BR exhibited maintained antioxidant activities, plastid membranal stability, and malondialdehyde (MDA) content. The chlorophyll fluorescence parameter values of F0 (42.23%) and Fv/Fm (36.67%) were also noticed to be higher; however, nearly three times higher levels of NPQ (375.86%) and Y (NPQ) (287.10%) were observed at 48 h of treatment as compared to all other group treatments. Increased Rubisco activity was also observed (62.89%), which suggested a significant role for elevated carbon fixation and assimilation and the upregulated expression of regulatory genes linked with Rubisco activity and the PSII reaction process. In short, we deduced that the 2.0 mg·L−1 BR application has an enhancing effect on the genetic modulation of physiological indices of melon plants against downy mildew disease stress. [ABSTRACT FROM AUTHOR]

Spinach (Spinacia oleracea) is an economically important leafy vegetable grown in the United States and world-wide. The downy mildew pathogen, Peronospora effusa (Pfs), is a major biotic constraint impacting spinach production and quality. The use of resistant cultivars is an economical and environmentally-friendly management option especially in organic production systems. As new races of the pathogen continue to appear, there is a need to continue to select for resistance to the emerging races. The objectives of this study were to evaluate a set of spinach hybrids and F2 breeding populations for resistance to Pfs race 5 to develop a better understanding of the genetics of downy mildew resistance. Also, we screened 39 commercial spinach cultivars for resistance to a recently identified race, Pfs race 19. The genetics of resistance to Pfs 5 was determined by greenhouse inoculations of F1 progeny (individual crosses between near isogenic lines, NIL3 or NIL1 and susceptible genotype, Viroflay) and F2 population progeny (cross between Califlay and susceptible Viroflay). Two hybrids were examined for resistance to Pfs 5. The results indicated that resistance conferred at the RPF1 or the RPF3 loci in a heterozygous (Rr) condition to Pfs 5 was completely dominant. Also, Chi-square analysis of the segregation pattern in the F2 population showed that resistance to Pfs race 5 was conferred by a single dominant gene. A total of 22 out of 39 spinach commercial cultivars were resistant to the newly reported Pfs race 19 and could be used in breeding programs to develop new cultivars with resistance to Pfs 19. [ABSTRACT FROM AUTHOR]

The oomycete Plasmopara viticola, which causes downy mildew, is currently one of the most destructive pathogens affecting grape production. Although native to the eastern United States, P. viticola was introduced into Europe in the mid-to-late 1800s and is now found in virtually every grape-growing region of the world. Since its discovery, much effort has been made to understand the life cycle and infection process of the pathogen to develop more effective management practices. Widespread application of fungicides, especially those which have only one mode of action, has led to an increased occurrence of resistance to these treatments. Thus, with increased fungicide resistance and rising environmental concerns surrounding their use, traditional chemical management practices have begun to fall out of favor. Newer approaches, from targeted breeding utilizing quantitative trait loci to biological control agents, are continually being investigated and adapted to limit the damage caused by downy mildew. This review summarizes the current knowledge of the pathogen and methods of its control and explores potential avenues for future research focused on hypovirulence and biological control agents. [ABSTRACT FROM AUTHOR]

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The genetic erosion of the European grapevine diversity in the last century has promoted the conservation of varieties in germplasm banks to prevent their disappearance. The study of these varieties is necessary as it would allow the diversification of the wine market, as well as provide a source of genes to face new pathogens or climate constraints. In this work, the grapevine varieties preserved in the "Estación de Viticultura e Enoloxía de Galicia" (EVEGA) Germplasm Bank (Ourense, Spain) were widely characterized, combining ampelography, ampelometry, agronomy, and phytopathology. Moreover, genetic characterization was carried out through the analysis of 48 single-nucleotide polymorphisms (SNPs). A Bayesian analysis based on the SNP data was carried out to define the genetic structure of the EVEGA Germplasm Bank, which allowed the differentiation of two main reconstructed panmictic populations (RPPs), confirming previous results obtained based on microsatellite markers (SSRs). A great diversity between varieties was found for almost every parameter evaluated for ampelography, ampelometry, phytopatology, phenology, and berry quality. A principal component analysis (PCA) performed with these phenotypical data allowed discrimination among some groups of varieties included in different genetic populations. This study allowed us to evaluate the grapevine diversity maintained in the EVEGA Germplasm Bank and characterize varieties of potential value for breeding programs of interest for the Galician viticulture. [ABSTRACT FROM AUTHOR]

Survey on cucumber plants at four Governorates in Egypt, revealed, root rot, gray mould blight and downy mildew a epidemic diseases. High incidence of root rot disease syndromes on cucumber plants in Kafr El-Sheickh (81.4%) followed by El - Giza (40%) Governorates, the common fungi associated were Fusarium solani and Fusarium oxysporum with high frequency of F. solani (84.2%) in Kafr El-Sheickh followed by F. oxysporum (75.0%) in El-Giza Governorates. Gray mould disease incidence of immature cucumber fruits was (35%) mainly caused by fungal of Botrytis cinerea with high frequency (90%) in El-Gharbeia Governorate. Downy mildew disease incidence of cucumber plants caused by Pseudoperonospora cubensis was epidemic in El-Gharbeia Governorate (80.0%) with high disease severity. On the other hand, the minor diseases occurrence were powdery mildew caused by Podosphaera fusca, moderately recorded at El-Giza followed Kafr El-Sheickh Governorates and white stem rot caused by fungi of Sclerotinia sclerotiorum in El-Beheira and El-Gharbeia Governorates respectively. So, the alternative fungicides such as biocontrol agents, chemicals non fungicides i.e., antioxidants, essential oils, and nanoparticles as eco-friendly agents will be consideration in integrated programme for avoiding diseases development to epidemic case, for improving yield quality and quantity. [ABSTRACT FROM AUTHOR]