Search Results (15)

In organic phytosanitary management of vineyards, it is crucial to understand the available pathogen control alternatives in order to progress towards a more sustainable form of viticulture. The objective of this study was to evaluate the efficacy of seven biofungicides registered in Chile for the prevention and treatment of Botrytis Bunch Rot (BBR), and to test a novel fungicide composed of chitosan and riboflavin (CH-RF). Biofungicides including Trichoderma spp., Aureobasidium pullulans, and Melaleuca alternifolia were evaluated using biotests with grapevine berries. Registered products (specifically biological control agents) significantly reduced the in vitro growth of B. cinerea. However, the degree of pathogen control varied significantly among products in grapevine berries of the Chardonnay cultivar, and disease incidence and severity changed depending on the inoculation time. High control effectiveness was achieved with two biofungicides, A. pullulans (average efficacy 34%) and M. alternifolia oil (average efficacy 29%). In vitro tests showed CH-RF significantly reduced mycelial growth of B. cinerea. Noticeable differences between the new CH-RF fungicide (incidence under 50% and infection score under 1) and A. pullulans- and M. alternifolia-based products were detected in grapevine berries. Therefore, the new experimental formulation CH-RF constitutes a promising alternative for the control of B. cinerea and provides a basis for further research. Full article

Black rot (BR), caused by Guignardia bidwellii, is an emergent fungal disease threatening viticulture and affecting several mildew-tolerant varieties. However, its genetic bases are not fully dissected yet. For this purpose, a segregating population derived from the cross ‘Merzling’ (hybrid, resistant) × ‘Teroldego’ (V. vinifera, susceptible) was evaluated for BR resistance at the shoot and bunch level. The progeny was genotyped with the GrapeReSeq Illumina 20K SNPchip, and 7175 SNPs were combined with 194 SSRs to generate a high-density linkage map of 1677 cM. The QTL analysis based on shoot trials confirmed the previously identified Resistance to Guignardia bidwellii (Rgb)1 locus on chromosome 14, which explained up to 29.2% of the phenotypic variance, reducing the genomic interval from 2.4 to 0.7 Mb. Upstream of Rgb1, this study revealed a new QTL explaining up to 79.9% of the variance for bunch resistance, designated Rgb3. The physical region encompassing the two QTLs does not underlie annotated resistance (R)-genes. The Rgb1 locus resulted enriched in genes belonging to phloem dynamics and mitochondrial proton transfer, while Rgb3 presented a cluster of pathogenesis-related Germin-like protein genes, promoters of the programmed cell death. These outcomes suggest a strong involvement of mitochondrial oxidative burst and phloem occlusion in BR resistance mechanisms and provide new molecular tools for grapevine marker-assisted breeding. Full article

Botrytis bunch rot of grapes (BBR) causes substantial crop and wine quality issues globally. Past and present foundations for BBR control are based upon synthetic fungicides and varying forms of canopy management. Many authors regard the continued dependence on fungicides as unsustainable and have urged greater deployment of cultural, biological and nutritional strategies. However, in contrast to organic wine production, the uptake of alternative strategies in conventional vineyards has been slow based on cost and perceived reliability issues. This review summarises research from many different wine growing regions in New Zealand with the aim of demonstrating how traditional and newly developed cultural control practices have cost-effectively reduced BBR. In addition to reviewing traditional cultural practices (e.g., leaf removal), mechanical tools are described that remove floral trash and mechanically shake the vines. Multi-omics has improved our knowledge of the underlying changes to grape berries after mechanical shaking. Exogenous applications of calcium may correct calcium deficiencies in the berry skin and reduce BBR but the outcome varies between cultivar and regions. Nitrogen aids in grapevine defence against BBR but remains a complex and difficult nutrient to manage. The sustainable growth of organics and The European Green Deal will stimulate researchers to evaluate new combinations of non-chemical BBR strategies in the next decade. Full article

In viticulture, winemakers and the industry demand grape bunches that have a reduced degree of bunch compactness. The major aspect is that a loose bunch compactness reduces the risk of severe Botrytis bunch-rot infections. Grapevine breeders focus hereby on several bunch-architecture-related traits. For specific breeding approaches and breeding-research-related topics, such as Quantitative Trait Locus (QTL) analysis or molecular marker development, the exact and objective phenotyping of such traits is mandatory. In this study, a precise and high-throughput 3D phenotyping pipeline was applied to screen 1514 genotypes from three mapping populations with different genetic backgrounds to investigate its applicability for QTL mapping approaches. In the first step, the phenotypic data of one population containing 150 genotypes were collected and analyzed with the 3D phenotyping pipeline. Additionally, corresponding reference data were obtained. Phenotypic values and results of a QTL analysis were compared with each other. Strongly positive correlations up to r = 0.93 between 3D and reference measurements could be detected for several traits. The ten-times-faster 3D phenotyping pipeline revealed 20, and the reference phenotyping methods revealed 22 QTLs. Eighteen of these QTLs were consistent between both procedures. In the next step, screening was extended to four different mapping populations across several seasons. In total, up to 1500 genotypes were screened during one season (>5000 grape bunches in total). The data analysis revealed significant differences across years and populations. Three bunch-architecture traits, including total berry volume, bunch width, and berry diameter, explained the highest amount of variability in the phenotypic data. A QTL analysis was performed on the phenotypic data of the involved populations to identify comparative genetic loci for bunch-architecture traits. Between 20 and 26 stable and reproducible QTLs for the investigated populations were detected. A common QTL for berry diameter could be identified for all populations. Our results strongly conclude that this locus is co-located on chromosome 17 when mapped to the grapevine reference genome. The results show that the implementation of the 3D phenotyping platform allows for precise and extended screenings of different, genetic diverse mapping populations and thus opens up the possibility to uncover the genomic architecture of this highly complex quantitative grapevine trait. Full article

The progressive reduction in the quantities of copper regulated by the European Union is focusing the research on new formulations with a reduced copper content but equally effective. In this regard, the activity of an Italian copper chabasite-rich zeolitite, which proved to be effective against grapevine grey mold and sour rot, was assessed against downy mildew. A two-year study was carried out in the Abruzzo region, Italy, in a cv. Montepulciano vineyard. The applications of the copper zeolitite showed the same good results obtained by a standard integrated/conventional strategy based on contact and systemic fungicides. At harvest, in both trial years, the plants with infected bunches in the untreated control ranged from 86.25% to 100%, compared to 15–30% of the treated plants. Furthermore, infected bunches and berries of the untreated control vines were 70–100% while treated ones never exceeded 2.32%. Furthermore, an increase in the polyphenol content and color intensity in wines made from vines treated with copper zeolitite was confirmed and appeared to be particularly evident in hot and dry seasons. The activity of copper zeolitite towards downy mildew, the potential use against grey mold and sour rot and the protection of grapes from high temperatures indicate that this product is a promising tool for a viticulture environmentally friendly control strategy. Full article

Noble rot is a favorable form of the interaction between grape (Vitis spp.) berries and the phytopathogenic fungus Botrytis cinerea. The transcriptome pattern of grapevine cells subject to natural noble rot development in the historic Hungarian Tokaj wine region has not been previously published. Furmint, a traditional white Tokaj variety suited to develop great quality noble rot was used in the experiments. Exploring a subset of the Furmint transcriptome redox and hormonal changes distinguishing between noble rot and bunch rot was revealed. Noble rot is defined by an early spike in abscisic acid (ABA) accumulation and a pronounced remodeling of ABA-related gene expression. Transcription of glutathione S-transferase isoforms is uniquely upregulated, whereas gene expression of some sectors of the antioxidative apparatus (e.g., catalases, carotenoid biosynthesis) is downregulated. These mRNA responses are lacking in berries exposed to bunch rot. Our results help to explain molecular details behind the fine and dynamic balance between noble rot and bunch rot development. Full article

Aureobasidium pullulans is a yeast-like fungus found on the surface of the grape berries that has been proven to act as a biocontrol agent for the management of grey mould disease caused by Botrytis cinerea. In this work, an indigenous strain of A. pullulans isolated from grape berries and selected according to the in vitro activity against B. cinerea, was used in vineyards of the winery where it originated, in comparison with a commercial product containing two A. pullulans strains with the aim of assessing its effectiveness as a biocontrol agent. The experimental design included daily meteorological data registration and the early defoliation of grapevines as treatments. The monitoring of A. pullulans strains on grape berries by plate counts and molecular methods as well as of B. cinerea symptoms on grape bunches was performed in the different trials from the end of flowering to the harvest time. Results highlighted that although no significant differences (p < 0.05) in the occurrence of B. cinerea were detected according to different treatments, the mean incidence of symptomatic berries ranged from 7 to 16%, with the lowest values recorded in bunches treated with the indigenous A. pullulans strain. The efficacy of the biocontrol agent was affected more by meteorological conditions than the defoliation practice. Full article

The aim of this study was to assess the resistance to sour rot of twenty-eight valuable cultivars of grapevine for wine production and twenty-five cultivars of table grapevine with diverse geographic and genetic origins, and to explain the causes of varied resistance based on the features related to the morphology, biology and ecology of assessed genotypes. The study was conducted for six years in the grapevine field collection of the National Institute of Horticultural Research in Skierniewice (Poland, latitude 51.9627 N, longitude 20.1666 E). Sour rot was severe in three seasons with abundant rainfall during the berry ripening stage. The number of wine and table cultivars in particular classes of resistance (mean value for three years) was as follows: very little or little—9 (wine) and 9 (table), medium—9 (wine) and 3 (table), high or very high—10 (wine) and 13 (table). The severity of bunch sour rot was positively correlated with single berry weight (moderate or weak correlation), bunch density and single bunch weight (very weak or weak correlation), and negatively correlated with thickness of berry skin (strong correlation) and the time of the beginning of veraison (weak correlation). Cultivars that were characterized by such agrobiological and ecological features as easy detachment of the berry from the pedicel, sensitivity to berry skin cracking, frequent damage to the skin by insects, and sensitivity to sunburn, were more heavily exposed to sour rot. Full article

Concern over environmental pollution generated by chemical fungicides has led to the introduction of alternative pest management strategies to chemical fungicide application. One of those strategies is the induction of plant defense response by an abiotic elicitor. In the present study, field-grown grapevines were subjected to electrical stimulation using a solar panel from two weeks before flowering to harvest in the 2016 and 2020 growing seasons. In both years, electrical stimulation decreased the incidence of gray mold and/or ripe rot on bunches and downy mildew on leaves of the field-grown grapevine. Transcription of a gene encoding β-1,3-glucanase but not class IV chitinase in leaves of potted grapevine seedlings was upregulated 20 days after electrical stimulation, suggesting that electrical stimulation acts as an abiotic elicitor of plant defense response to fungal diseases. The gene expression of PR1 but not PDF1.2 was upregulated in Arabidopsis plants subjected to electrical stimulation. On the other hand, PR1 gene expression was not induced in salicylic acid (SA)-insensitive Arabidopsis mutant npr1-5 subjected to electrical stimulation. Taken together, electrical stimulation is responsible for plant defense response through the SA-dependent defense pathway. These findings would help us develop a novel and innovative practical technique that uses electrical stimulation in integrated pest management. Full article

Grapevine bunch rot, caused by Botrytis cinerea and Aspergillus carbonarius, causes important economic losses every year in grape production. In the present study, we examined the plant protective activity of the biological control agents, Paenibacillus alvei K165, Blastobotrys sp. FP12 and Arthrobacter sp. FP15 against B. cinerea and A. carbonarius on grapes. The in vitro experiments showed that strain K165 significantly reduced the growth of both fungi, while FP15 restricted the growth of A. carbonarius and FP12 was ineffective. Following the in vitro experiments, we conducted in planta experiments on grape berries. It was shown that K165, FP12 and FP15 reduced A. carbonarius rot severity by 81%, 57% and 37%, respectively, compared to the control, whereas, in the case of B. cinerea, the only protective treatment was that with K165, which reduced rot by 75%. The transcriptomic analysis of the genes encoding the pathogenesis-related proteins PR2, PR3, PR4 and PR5 indicates the activation of multiple defense responses involved in the biocontrol activity of the examined biocontrol agents. Full article

In recent years, researchers have increasingly explored sustainable tools for plant protection against pathogens, including the use of biological control agents (BCAs), which have the potential to complement or replace chemical fungicides. However, global reliance on their use remains relatively insignificant and the factors influencing their efficacy remain unclear. The complex interactions among a target pathogen, a host plant, and the BCA population in a changing environment can be studied by process-based, weather-driven mathematical models, able to interpret the combined effects on BCA efficacy of: (i) BCA mechanism of action, (ii) timing of BCA application with respect to timing of pathogen infection (preventative vs. curative), (iii) temperature and moisture requirements for both pathogen and BCA growth, and (iv) BCA survival capability. When the model was used under three contrasting weather conditions for the control of Botrytis bunch rot in grapevine, BCA efficacy was mostly influenced by environmental conditions, accounting for > 90% of the variance in simulated biocontrol efficacy. These findings indicate that the environmental responses of BCAs should be considered during their selection, BCA survival capability should be considered during both selection and formulation, and weather conditions and forecasts should be considered at the time of BCA application in the field. Different commercial BCAs for the control of Botrytis cinerea showed different environmental requirements and adaptation capabilities; therefore, the most suitable BCA to be used for a specific field application may consider weather conditions and forecasts at the time of intervention. Full article

Since 2006, an increasing number of French vineyards have chosen to convert to organic farming. One major change in vineyard practices includes replacing chemical pesticides with copper and sulfur-based products in line with Council Regulation (EC) No. 834/2007. This change can make overall management and pest and disease control more difficult and potentially lead to yield losses. From 2013 to 2016, a network of 48 vineyard plots, in southern France, under conventional management and in conversion to organic farming were monitored throughout the three-year conversion phase to investigate the grapevine phytosanitary management of four major pests and diseases and variations in control efficiency. The severity of downy and powdery mildew, grape berry moths, and Botrytis bunch rot were assessed and linked to the protection strategy. The findings showed that pests and diseases were controlled in the third year of conversion at similar efficiency levels as in conventional farming. However, the first two years of conversion were a transitional and less successful period during which higher incidences of cryptogamic diseases were observed. This demonstrates a need for winegrowers to receive more in-depth technical advice and support, especially on pest and disease control, during this critical transition period. Full article

In grapevine breeding, loose grape bunch architecture is one of the most important selection traits, contributing to an increased resilience towards Botrytis bunch rot. Grape bunch architecture is mainly influenced by the berry number, berry size, the total berry volume, and bunch width and length. For an objective, precise, and high-throughput assessment of these architectural traits, the 3D imaging sensor Artec^® Spider was applied to gather dense point clouds of the visible side of grape bunches directly in the field. Data acquisition in the field is much faster and non-destructive in comparison to lab applications but results in incomplete point clouds and, thus, mostly incomplete phenotypic values. Therefore, lab scans of whole bunches (360°) were used as ground truth. We observed strong correlations between field and lab data but also shifts in mean and max values, especially for the berry number and total berry volume. For this reason, the present study is focused on the training and validation of different predictive regression models using 3D data from approximately 2000 different grape bunches in order to predict incomplete bunch traits from field data. Modeling concepts included simple linear regression and machine learning-based approaches. The support vector machine was the best and most robust regression model, predicting the phenotypic traits with an R² of 0.70–0.91. As a breeding orientated proof-of-concept, we additionally performed a Quantitative Trait Loci (QTL)-analysis with both the field modeled and lab data. All types of data resulted in joint QTL regions, indicating that this innovative, fast, and non-destructive phenotyping method is also applicable for molecular marker development and grapevine breeding research. Full article

Wine growers prefer cultivars with looser bunch architecture because of the decreased risk for bunch rot. As a consequence, grapevine breeders have to select seedlings and new cultivars with regard to appropriate bunch traits. Bunch architecture is a mosaic of different single traits which makes phenotyping labor-intensive and time-consuming. In the present study, a fast and high-precision phenotyping pipeline was developed. The optical sensor Artec Spider 3D scanner (Artec 3D, L-1466, Luxembourg) was used to generate dense 3D point clouds of grapevine bunches under lab conditions and an automated analysis software called 3D-Bunch-Tool was developed to extract different single 3D bunch traits, i.e., the number of berries, berry diameter, single berry volume, total volume of berries, convex hull volume of grapes, bunch width and bunch length. The method was validated on whole bunches of different grapevine cultivars and phenotypic variable breeding material. Reliable phenotypic data were obtained which show high significant correlations (up to r² = 0.95 for berry number) compared to ground truth data. Moreover, it was shown that the Artec Spider can be used directly in the field where achieved data show comparable precision with regard to the lab application. This non-invasive and non-contact field application facilitates the first high-precision phenotyping pipeline based on 3D bunch traits in large plant sets. Full article

Warm and moist weather conditions during berry ripening provoke Botrytis cinerea (B. cinerea) causing notable bunch rot on susceptible grapevines with the effect of reduced yield and wine quality. Resistance donors of genetic loci to increase B. cinerea resistance are widely unknown. Promising traits of resistance are represented by physical features like the thickness and permeability of the grape berry cuticle. Sensor-based phenotyping methods or genetic markers are rare for such traits. In the present study, the simple-to-handle I-sensor was developed. The sensor enables the fast and reliable measurement of electrical impedance of the grape berry cuticles and its epicuticular waxes (CW). Statistical experiments revealed highly significant correlations between relative impedance of CW and the resistance of grapevines to B. cinerea. Thus, the relative impedance Z_rel of CW was identified as the most important phenotypic factor with regard to the prediction of grapevine resistance to B. cinerea. An ordinal logistic regression analysis revealed a R²_McFadden of 0.37 and confirmed the application of Z_rel of CW for the prediction of bunch infection and in this way as novel phenotyping trait. Applying the I-sensor, a preliminary QTL region was identified indicating that the novel phenotypic trait is as well a valuable tool for genetic analyses. Full article