scholarly journals Plasmopara viticola causing downy mildew on Vitis davidii in Korea

Plant Disease ◽  
2021 ◽  
Author(s):  
Bora Kim ◽  
Jae Sung Lee ◽  
Young-Joon Choi
Keyword(s):  
Downy Mildew ◽  
Disease Incidence ◽  
Plasmopara Viticola ◽  
Central China ◽  
Representative Specimen ◽  
Pathogenicity Test ◽  
Beta Tubulin ◽  
Vitis Species ◽  
Molecular Features ◽  
Vitis Davidii

Vitis davidii (Rom.Caill.) Foëx, commonly known as spine grape, is a deciduous climber native to China. Its fruits are consumed fresh or used to make wine in South and Central China. In recent years, spine grape has been cultivated in Korea. In July 2020, downy mildew was detected on spine grape vines in Jeongeup (35°42′17″N, 126°54′02″E), Korea, with a disease incidence of 70%. The symptoms appeared as yellowish, brownish, or reddish, vein-limited, poly-angular adaxial leaf spots, correspond to dense, white downy growth abaxially. A representative specimen was deposited in the Kunsan National University Herbarium (KSNUH679). Sporangiophores were tree-like, hyaline, mostly straight, and monopodially branched in orders of three to six; they measured (219.4–)273.2 to 435.1(–546.6) × (4.8–)6.7 to 9.0(–10.0) μm (n = 50). Ultimate branchlets were bi or trifurcate, straight to slightly curved, with truncate or, rarely, a swollen tip and measured 2.9 to 9.7 μm long and 0.8 to 2.5 μm wide at the base (n = 50). Sporangia were hyaline, ovoidal or lemon-shaped; they measured (16.8–)20.0 to 28.8(–34.2) × (11.4–)13.1 to 17.0(–20.1) μm with a length to width ratio of (1.28–)1.46 to 1.78(–2.07) (n = 50). This morphology was as described for Plasmopara viticola (Berk. & M. A. Curtis) Berl. & De Toni (Hall, 1989). Genomic DNA was extracted directly from infected V. davidii leaves. Three regions were PCR-amplified and sequenced: cox2 mtDNA with primers cox2F and cox2-RC4 (Choi et al., 2015), actin with primers pve04815-F and pve04815-R, and beta-tubulin with primers pvc389-F3 and pvc389-R4 (Rouxel et al., 2013). The resulting sequences were deposited in GenBank (accession nos. MT834527 for cox2, MT834525 for actin, and MT834526 for beta-tubulin). A BLASTn search revealed that the Korean sample was identical to P. viticola clade aestivalis originating from Vitis species: MK215072 for cox2 sequence, KY933800 for actin, and MK358393 for beta-tubulin. In all phylogenetic analyses of the three genes (cox2, actin, and beta-tubulin), KSNUH679 came out as phylogenetically place within P. viticola clade aestivalis, which has recently been reported on V. coignetiae and V. ficifolia var. sinuata in Korea (Kim et al., 2019). A pathogenicity test was performed twice by inoculating the leaves of 10 healthy spine grape plants with a sporangial suspension (~1 × 106 sporangia·mL-1) and incubating them in a growth chamber at 25 °C, 12-h day/night cycle, and 90% relative humidity; five non-inoculated plants served as controls. After two weeks, all inoculated plants developed typical downy mildew symptoms could be observed, whereas the controls remained symptomless. Morphology and molecular features confirmed the identity of the pathogen of spine grape to be P. viticola. To the best of our knowledge, this is the first report of downy mildew caused by P. viticola on V. davidii in Korea. Recently, downy mildew outbreaks caused by P. viticola have been recorded in spine grape plantations in southern China (Yi et al., 2019). Considering the potential of spine grape as a novel crop for Korea, P. viticola appears to represent a significant threat to this industry.

scholarly journals The Grapevine E3 Ubiquitin Ligase VriATL156 Confers Resistance against the Downy Mildew Pathogen Plasmopara viticola

2021 ◽  
Vol 22 (2) ◽  
pp. 940
Author(s):  
Elodie Vandelle ◽  
Pietro Ariani ◽  
Alice Regaiolo ◽  
Davide Danzi ◽  
Arianna Lovato ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Ubiquitin Ligase ◽  
Control Measure ◽  
Durable Resistance ◽  
Genetic Resistance ◽  
E3 Ubiquitin Ligase ◽  
Plasmopara Viticola ◽  
Vitis Vinifera L ◽  
Vitis Species ◽  
Vitis Riparia

Downy mildew, caused by Plasmopara viticola, is one of the most severe diseases of grapevine (Vitis vinifera L.). Genetic resistance is an effective and sustainable control strategy, but major resistance genes (encoding receptors for specific pathogen effectors) introgressed from wild Vitis species, although effective, may be non-durable because the pathogen can evolve to avoid specific recognition. Previous transcriptomic studies in the resistant species Vitis riparia highlighted the activation of signal transduction components during infection. The transfer of such components to V. vinifera might confer less specific and therefore more durable resistance. Here, we describe the generation of transgenic V. vinifera lines constitutively expressing the V. riparia E3 ubiquitin ligase gene VriATL156. Phenotypic and molecular analysis revealed that the transgenic plants were less susceptible to P. viticola than vector-only controls, confirming the role of this E3 ubiquitin ligase in the innate immune response. Two independent transgenic lines were selected for detailed analysis of the resistance phenotype by RNA-Seq and microscopy, revealing the profound reprogramming of transcription to achieve resistance that operates from the earliest stages of pathogen infection. The introduction of VriATL156 into elite grapevine cultivars could therefore provide an effective and sustainable control measure against downy mildew.

scholarly journals Evaluation of a Disease Warning System for Downy Mildew of Grapes

Plant Disease ◽  
2000 ◽  
Vol 84 (5) ◽  
pp. 549-554 ◽  
Author(s):  
L. V. Madden ◽  
M. A. Ellis ◽  
N. Lalancette ◽  
G. Hughes ◽  
L. L. Wilson
Keyword(s):  
Linear Model ◽  
Downy Mildew ◽  
Environmental Conditions ◽  
Generalized Linear Model ◽  
Disease Incidence ◽  
Warning System ◽  
Plasmopara Viticola ◽  
Effective Control ◽  
Subsequent Infection ◽  
Grape Downy Mildew

An electronic warning system for grape downy mildew— based on models for the infection of leaves of Vitis lambrusca, production of sporangia by Plasmopara viticola in lesions, and sporangial survival—was tested over 7 years in Ohio. Grapevines were sprayed with metalaxyl plus mancozeb (Ridomil MZ58) when the warning system indicated that environmental conditions were favorable for sporulation and subsequent infection. Over the 7 years, plots were sprayed from one to four times according to the warning system, and from four to 10 times according to the standard calendar-based schedule (depending on the date of the initiation of the experiment). The warning system resulted in yearly reductions of one to six sprays (with median of three sprays). Disease incidence (i.e., proportion of leaves with symptoms) in unsprayed plots at the end of the season ranged from 0 to 86%, with a median of 68%. Incidence generally was very similar for the warning-system and standard-schedule treatments (median of 7% of the leaves with symptoms), and both of these incidence values were significantly lower (P < 0.05) than that found for the unsprayed control, based on a generalized-linear-model analysis. Simplifications of the disease warning system, where sprays were applied based only on the infection or sporulation components of the system, were also effective in controlling the disease, although more fungicide applications sometimes were applied. Effective control of downy mildew, therefore, can be achieved with the use of the warning system with fewer sprays than a with a standard schedule.

scholarly journals IMPROVED DOWNY MILDEW CONTROL IN WINE GRAPES WITH VOSSEN BLUE

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 605d-605
Author(s):  
Joseph A. Fiola ◽  
Gary C. Pavlis
Keyword(s):  
Downy Mildew ◽  
Disease Incidence ◽  
Total Yield ◽  
Economic Loss ◽  
Plasmopara Viticola ◽  
Wine Grapes ◽  
Incidence Data ◽  
Average Cluster ◽  
Grape Cultivars ◽  
Downy Mildew Disease

Downy Mildew, Plasmopara viticola, causes major damage and economic loss to many wine grape cultivars grown in the Northeast. The purpose of the experiment was to test the efficacy of Vossen Blue (VB; iron pigment) in association with fungicides for the control of Downy Mildew disease of wine grapes in New Jersey. The experimental plot was a planting of `Seyval Blanc' (5th leaf). Treatments (applied via back-pack sprayer) included no fungicide (control I), full fungicide (FF) (RCE commercial recs; control II), FF + 4%VB, FF + 8%VB, 8%VB, Half Rate Fungicide (HF) + 4%VB, HF + 8%VB. There were no significant differences between treatments for total yield, average cluster weight, average berry weight, Brix %, and pH. Spectrophotometric (Hunter's Lab) analysis of foliage samples revealed that leaf samples from the VB treatments had greater green color (correlate: increased chlorophyll). Analysis of subjective (1-9) disease incidence data: FF8 significantly lower disease score that FF; FF4, HF4, HF8, and FF no difference. Compared to normal full fungicide: superior Downy Mildew control was achieved by adding VB to full fungicide; equal control was achieved with half fungicide and VB.

scholarly journals Salvia officinalis Extract Can Protect Grapevine Against Plasmopara viticola

Plant Disease ◽  
2010 ◽  
Vol 94 (5) ◽  
pp. 575-580 ◽  
Author(s):  
Silvia Dagostin ◽  
Tiziano Formolo ◽  
Oscar Giovannini ◽  
Ilaria Pertot ◽  
Annegret Schmitt
Keyword(s):  
Disease Control ◽  
Downy Mildew ◽  
Disease Incidence ◽  
Plasmopara Viticola ◽  
Salvia Officinalis ◽  
Promising Alternative ◽  
Rainy Period ◽  
Grapevine Downy Mildew ◽  
Progress Curve ◽  
High Level

The ability of sage (Salvia officinalis) extract to control grapevine downy mildew under greenhouse and field conditions was tested. The persistence and rainfastness of sage extract were also investigated. Sage extract provided a high level of sustained disease control in artificially inoculated, potted grapevine under greenhouse conditions. However, even small amounts of simulated rainfall (10 mm) significantly reduced efficacy of sage extract. In a field experiment in 2006, sage extract provided 94% reduction in disease incidence and 63% reduction in area under the disease progress curve for disease severity on berries and leaves, respectively, reaching a level of disease control not significantly different from that provided by copper hydroxide. In 2007, the sage extract provided only a partial reduction (less than 30%) of downy mildew on leaves, probably as a result of a long rainy period between two of the consecutive treatments. Overall, sage extract effectively controlled grapevine downy mildew and could be a promising alternative to copper in organic viticulture. However, the low rainfastness of this treatment adversely affected its efficacy.

scholarly journals Evaluation of foliar resistance of grapevine genetic resources to downy mildew (Plasmopara viticola)

2012 ◽  
Vol 60 (8) ◽  
pp. 191-198 ◽  
Author(s):  
Pavel Pavloušek
Keyword(s):  
Downy Mildew ◽  
Disease Incidence ◽  
Natural Infection ◽  
Plasmopara Viticola ◽  
Methods Of Evaluation ◽  
Infection Pressure ◽  
Foliar Resistance ◽  
Term Evaluation ◽  
Term Field

In this study altogether the resistance of 44 grapevine cultivars to downy mildew was evaluated in a long-term field experiment (1996–2003). The resistance was evaluated under conditions of a natural infection pressure using the OIV 452 scale as well as on the base of the evaluation of disease incidence of sporulation and disease incidence of necrosis. The highest degree of resistance to downy mildew was found out in resistance donors Seyve Villard 12 375, Seibel 13 666 and Bianca cultivar. High correlations existing among individual methods of evaluation indicated a good applicability of all tested methods. The evaluation of disease incidence of sporulation and disease incidence of necrosis demonstrated the dependence of traits associated with the resistance to downy mildew on the colour of berries. When evaluating the correlation existing between the resistance and pedigree, it was demonstrated that the highest average resistance existed in cultivars that had the cultivar Seyve Villard 12 375 as the donor of resistance in their pedigree. Basing on obtained results it can be concluded that the OIV 452 scale can be considered as the basic method of resistance evaluation to downy mildew, above all in cases of a long-term evaluation under field conditions.

scholarly journals Nigrospora oryzae Causing Leaf Spot on Asiatic Dayflower in Chongqing, China

Plant Disease ◽  
2021 ◽  
Author(s):  
Chaodong Qiu ◽  
Wenhui Zhu ◽  
Taotao Niu ◽  
Zhenyu Liu
Keyword(s):  
Leaf Spot ◽  
Disease Incidence ◽  
Aerial Mycelium ◽  
Tween 20 ◽  
Post Inoculation ◽  
Pathogenicity Test ◽  
Distilled Water ◽  
Beta Tubulin ◽  
Leaf Lesion ◽  
Nigrospora Oryzae

Asiatic dayflower (Commelina communis L.) is an annual herbaceous weed that is distributed throughout China. A foliar disease on Asiatic dayflowers was discovered in one farm field in Dianjiang County, Chongqing, China (N30°3´22″, E107°18´5″) in summer, 2019. The disease incidence was observed on about 10% (13/127) of the plants. Symptoms appeared as round-shaped tan lesions (2-5 mm) in diameter that occurred randomly and irregularly on the whole leaves. The centers of lesions become grayish white with reddish borders as the disease progressed. The leaves with typical symptoms were detached and wiped with 70% ethanol for surface disinfestation before isolating the causal agent. Subsequently, three pieces (3-4 mm2) of tissue were taken from the margin of the leaf lesion, disinfested in 1.5% NaClO for 1 min, rinsed 3 times in sterilized distilled water, and placed onto Potato Dextrose Agar (PDA) medium containing 50 μg/ml each of kanamycin and ampicillin. A fungus was exclusively and consistently isolated from the disinfested leaf lesion sections. The colonies on PDA grew rapidly and covered the entire petri dish within 5 days at 28℃. Colonies were at first grayish white, cotton wool-like, round, with abundant aerial mycelium, and later turned black as conidia produced. The abundant conidia formed on PDA were initially yellow brown and gradually became black, oblate to ellipsoidal, smooth, single-celled, and ranged in size from 4 to 10 × 3.5 to 9 μm. They were borne on a colorless, hyaline, and inverted flask-shaped cell at the tip of each conidiophore. The morphology characteristics were consistent with those of Nigrospora spp. (Wang et al. 2017). Genomic DNA was extracted from one representative isolate NDJ0819. The amplification and sequencing of the gene fragments including the internal transcribed space (ITS) region of ribosomal DNA and beta-tubulin were performed using the primers ITS1/ITS4 (White et al. 1990) and Bt2a/Bt2b (Glass and Donaldson 1995), respectively. Fragments of 536 bp for ITS and 408 bp for beta-tubulin were obtained. A phylogram of the combined ITS and beta-tubulin sequences reconstructed using the maximum likelihood bootstrapping method implemented in the software MEGA version 7.0 (Kumar et al. 2016) indicated that isolate NDJ0819 clustered with Nigrospora oryzae. Both ITS and beta-tubulin sequences were deposited into GenBank (accession no. MT140353 and MT157509, respectively). Pathogenicity test was performed by rub-inoculating needle-wounded leaves of three 4-week-old Asiatic dayflowers with spore suspension (2.6 × 106 conidia/ml) of NDJ0819 prepared in water containing 0.05% Tween-20, and holding plants at 28℃ in the growth chamber. The pathogenicity test was repeated twice. Brown, round-shaped lesions developed on leaves inoculated with spores at 15 days post-inoculation. However, the centers of the lesion did not become grayish white, compared to those of lesions seen in naturally infected leaves. No symptoms developed on leaves inoculated with sterilized distilled water. N. oryzae was re-isolated from the lesions. All results described above indicated that N. oryzae was responsible for the leaf spot of Asiatic dayflower. To our knowledge, this is the first report of N. oryzae causing leaf spot on Asiatic dayflower in China. Research into the potential use of N. oryzae as a candidate biological agent against the weed is worth being initiated.

scholarly journals Distinctive Symptoms and Signs of Downy Mildew on Cold-Climate Wine Grape Cultivars

2017 ◽  
Vol 18 (3) ◽  
pp. 192-195
Author(s):  
David S. Jones ◽  
Patricia S. McManus
Keyword(s):  
Downy Mildew ◽  
Plasmopara Viticola ◽  
Disease Diagnosis ◽  
Cold Climate ◽  
Wine Industry ◽  
Vitis Species ◽  
Incorrect Diagnosis ◽  
Northern United States ◽  
Cold Hardy ◽  
Symptoms And Signs

Downy mildew, caused Plasmopara viticola, is a major disease affecting grape production worldwide. While the symptoms and signs of downy mildew on European wine grapes (Vitis vinifera) are well documented, minimal information is available regarding the symptoms and signs on cold-hardy cultivars that are crosses of V. vinifera and Vitis species native to North America. Referred to as “cold-climate cultivars,” these hybrids have been released over the past two decades and form the basis of a burgeoning wine industry in the northern United States. Most research on downy mildew of grape has involved V. vinifera, and consequently, many images used for educational purposes illustrate “classic” symptoms and signs on highly susceptible cultivars of V. vinifera. However, we have observed that such images can be inconsistent with symptomology in the cold-climate grape hybrids, and there are differences in the symptoms and signs of downy mildew among cold-climate cultivars. These inconsistencies can result in incorrect diagnosis, which can lead to poor management decisions, including application of products that are not appropriate for the pathogen(s) present. Thus, the objective of the current guide is to describe downy mildew symptoms and signs on cold-climate cultivars, with special attention to features that are not documented in resources widely used for grape disease diagnosis.

scholarly journals The Mode of Host Resistance to Plasmopara viticola Infection of Grapevines

2012 ◽  
Vol 102 (11) ◽  
pp. 1094-1101 ◽  
Author(s):  
Ying Yu ◽  
Yali Zhang ◽  
Ling Yin ◽  
Jiang Lu
Keyword(s):  
Vitis Vinifera ◽  
Downy Mildew ◽  
Host Resistance ◽  
Plasmopara Viticola ◽  
The Other ◽  
Pathogen Infection ◽  
Vitis Species ◽  
Time Courses ◽  
Degrees Of Severity

The resistance and susceptibility of grapevines to downy mildew (DM) disease caused by Plasmopara viticola were compared among different cultivars/accessions belonging to Vitis vinifera, V. rotundifolia, and 10 oriental Vitis species. After inoculation with P. viticola pathogen, no symptom was found in V. rotundifolia grapevines at all, while oriental species V. davidii and V. piasezkii, like V. vinifera, were susceptible to DM disease. The other eight oriental Vitis species showed various resistance levels to DM disease. Intraspecific resistant variations were also observed in V. amurensis. Microscopy studies were conducted on various time courses after pathogen infection on grape leaves. P. viticola hyphae were not observed in V. rotundifolia cultivars, while symptoms with varying degrees of severity were observed among the Euvitis species. In general, the DM resistant oriental species showed a slower development of hypha and less formation of haustoria than DM susceptible V. vinifera grapevines. Cells with distinctive fluorescence were observed in V. rotundifolia and the oriental species V. pseudoreticulata, and callose deposits were observed in V. rotundifolia, V. pseudoreticulata, and V. amurensis grapevines. Based on the results of morphological observations and microscopy studies, we concluded that there were five levels of grapevine resistance to P. viticola pathogen: (i) immune, (ii) extremely resistant, (iii) resistant, (iv) partly resistant, and (v) susceptible.

scholarly journals Epidemiological Model based Decision Support System for the Management of Grapes Downy Mildew

2020 ◽  
Vol 107 ◽  
pp. 1-4
Author(s):  
Sendhilvel v ◽  
◽  
Marimuthu T ◽  
Geetha Lakshmi V ◽  
◽  
...  
Keyword(s):  
Decision Support ◽  
Downy Mildew ◽  
Disease Incidence ◽  
Cost Effective ◽  
Plasmopara Viticola ◽  
Logistic Equation ◽  
Biological Data ◽  
Epidemiological Model ◽  
Progress Curve ◽  
Weather Parameters

Grapevine downy mildew caused by Plasmopara viticola is an explosivedisease that causes severe damage to leaf, flowers and fruits of the vine.In the present study, an epidemiological model was developed to supportthe vine-growers to reduce the number of fungicidal sprays and protect theenvironmental hazards besides saving the input cost. To record the weatherdata, an automatic weather station was installed at Mathampatti Village,Coimbatore, India and the weather parameters such as relative humidity,minimum, maximum and night temperatures, rainfall, leaf wetness, dew fall,solar radiation etc., were recorded at once in a 10 minutes interval during2014-17. A logistic equation was designed based on the biological data(disease incidence, weather parameter and crop age) and its mathematicalanalysis was shown in this paper. The critical weather parameters werestudied using logistic equation with the support of “Curve expert programme”.The mode described the development of the infection and infection ratethrough computation-based analysis. The Decision Support Systems (DSS)were arrived using the disease progress curve obtained from the logisticequation. The DSS indicates the first two sprays during the congenial phaseof the disease from 25 to 45 Days After Pruning (DAP). Then the secondphase, ie rapid growth stage was termed as ‘Exponential phase’, in which twosprays on 55 and 65 DAP (flowering and fruiting stage) were carried out. Inthe final plateau phase (66 DAP to till harvest), the management strategiesapplied would not be cost-effective and no spray was recommended. Thefield experiment was carried out using the findings of the logistic equationwith different management modules for validation. The number of spraysof fungicide was reduced from 15 to 5 times in the logistic equation-basedtreated plot.

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