Current status and future prospects of grapevine anthracnose caused by Elsinoe ampelina: An important disease in humid grape-growing regions

Quantitative Insights into Grapevine Anthracnose (Elsinoë ampelina) Epidemiology: Impact of Temperature and Leaf Age on Incubation, Lesion Development, and Sporulation

Grapevine anthracnose, caused by Elsinoë ampelina, is one of the most devastating diseases for wine and table grapes, particularly in hot, humid regions. This study explores how temperature and leaf age affect incubation and how temperature affects lesion development and sporulation. The influence of temperature and leaf age on incubation period (days) was tested under controlled conditions. Leaves from 1 to 8 days old were inoculated and maintained at temperatures of 5, 10, 15, 20, 25, and 30°C. The time elapsed between inoculation and the emergence of initial lesions was recorded. The effect of temperature on lesion development and sporulation was investigated under vineyard conditions. This was achieved through artificial inoculations, with 17, 11, and 11 inoculations conducted in 2016, 2017, and 2018, respectively. The average incubation period, considering all leaf ages, was 27.50 days at 5°C, 15.10 days at 10°C, 9.70 days at 15°C, 5.90 days at 20°C, 3.70 days at 25°C, and 2.26 days at 30°C. Regardless of temperature, the average incubation period was 3.6, 5.9, 8.3, 9.8, 11.9, 13.4, 15.6, and 17.1 days for leaves 1, 2, 3, 4, 5, 6, 7, and 8 days old, respectively. The exponential decay model accurately describes the incubation period as a function of both temperature and leaf age. On average, the relative lesion development (RLD) was 0.00, 0.00, 0.23, 0.47, 0.72, 0.93, 0.92, 0.90, 0.94, and 1.0 at 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 days after inoculation, respectively. The average relative sporulation (RSPO) was 0.03, 0.36, 0.82, 0.96, and 1.0 at 5, 10, 15, 20, and 25 days after inoculation, respectively. Both RLD and RSPO as a function of degree-days (Tbase = 0°C) since inoculation were well described by the logistic function. The rates of change in RLD and RSPO were 0.055 and 0.032, respectively. The results of this study provide new quantitative insights into three important stages (monocyclic processes) in the development of grapevine anthracnose caused by E. ampelina.

Metabolomics analysis based on UHPLC-QqQ-MS/MS to discriminate grapes and wines from different geographical origins and climatological characteristics

With the proliferation of the consumer's awareness of wine provenance, wines with unique origin characteristics are increasingly in demand. This study aimed to investigate the influence of geographical origins and climatological characteristics on grapes and wines. A total of 94 anthocyanins and 78 non-anthocyanin phenolic compounds in grapes and wines from five Chinese viticultural vineyards (CJ, WH, QTX, WW, and XY) were identified by UHPLC-QqQ-MS/MS. Chemometric methods PCA and OPLS-DA were established to select candidate differential metabolites, including flavonols, stilbenes, hydroxycinnamic acids, peonidin derivatives, and malvidin derivatives. CCA showed that malvidin-3-O-glucoside had a positive correlation with mean temperature, and quercetin-3-O-glucoside had a negative correlation with precipitation. In addition, enrichment analysis elucidated that the metabolic diversity in different origins mainly occurred in flavonoid biosynthesis. This study would provide some new insights to understand the effect of geographical origins and climatological characteristics on phenolic compounds in grapes and wines.

Determination, temporal variation and potential health risk assessment of pesticide residues in grapes from South and Southwest China

Pesticide residues in grapes from South and Southwest China were determined using the QuEChERS procedure and UHPLC-MS/MS and GC-MS/MS methods. The 4-year monitoring and survey showed 94.6% of the 1341 samples of grapes collected from eight main production areas contained one or multiple pesticide residues (above the respective LOQs). Overall, 40 pesticides were detected, including 24 fungicides, 12 insecticides, 2 acaricides and 2 plant growth modulators, of which one pesticide was unauthorised for use in treating grapes. Two or more pesticide residues were discovered in 87.4% of the samples (above the respective LOQs), and pesticide residues in 5.7% of the samples exceeded the MRLs, such as difenoconazole, cyhalothrin, propiconazole, etc. The main risk factors affecting the safety of grape before 2019 were difenoconazole, cyhalothrin and cyazofamid. After 2019, however, the frequency of occurrence of the above pesticides significantly declined, and the banned or restricted pesticides including omethoate were not found, which was credited to the stricter supervision and management policies by local governments. Despite the high detection rates and multi-residue occurrence of pesticides in grapes, about 84% of the samples were compliant with regulatory standards. Moreover, the accumulative chronic diet risk determined from ADI is very low. This study and timely monitoring can ensure that grape growers comply with GAP and minimise the occurrence of residues.

Cluster Zone Leaf Removal Reduces the Rate of Anthracnose (Elsinöe ampelina) Progress and Facilitates Its Control

Anthracnose caused by Elsinöe ampelina is an economically important disease that affects certain hardy and semihardy grapevine cultivars. The control of this disease requires repeated application of fungicides, which has financial and environmental consequences. In this study, leaf removal in the cluster area was studied with a view to facilitating integrated anthracnose management. First, the effect of leaf removal timing (BBCH stage 53 or 71) and intensity (one or both sides of rows) on the progression of anthracnose and on the microclimate was studied in plots planted with Vidal blanc (Vitis vinifera) at two sites in both 2020 and 2021. Overall, at both sites and in both years, anthracnose on leaves was more severe in plots without cluster zone leaf removal. Regardless of the timing of leaf removal, anthracnose severity on leaves and incidence of infected berries at harvest were significantly lower in plots where leaves had been removed on both sides of the rows compared with plots where leaves were removed on one side only. Second, anthracnose management programs with leaf removal, with or without disease risk estimation, were evaluated. All anthracnose management programs including leaf removal in the cluster zone reduced anthracnose development compared with the standard program without leaf removal. Overall mean leaf anthracnose severity, severity at harvest, and anthracnose incidence on clusters at harvest were lower in plots with leaf removal than in the standard program, but the differences between the two treatments were not significant (P > 0.05). More fungicide applications were made in plots managed using the standard programs, specifically 13 applications, compared with plots managed based on assessing the weather-related risk of anthracnose, with 9 and 10 applications made at sites 1 and 2 for the risk-based program, respectively, and 5 and 7 applications made at sites 1 and 2, respectively, when microclimate within the cluster zone was considered. The results of this study clearly show the important role that leaf removal can play in managing grape anthracnose.

Characterisation of the mating-type loci in species of Elsinoe causing scab diseases

The genus Elsinoe includes many aggressive plant pathogens that infect various economically important agricultural, horticultural and forestry plants. Significant diseases include citrus scab caused by E. fawcettii and E. australis, grapevine spot anthracnose by E. ampelina, and the emerging Eucalyptus scab and shoot malformation disease caused by the recently described E. necatrix. Despite their importance as plant pathogens, little is known regarding the biology of many Elsinoe spp. To gain insights into the reproductive biology of these fungi, we characterized the mating-type loci of seven species using whole genome sequence data. Results showed that the MAT1 locus organization and its flanking genes is relatively conserved in most cases. All seven species manifested a typical heterothallic mating system characterized by having either the MAT1-1 or MAT1-2 idiomorph present in an isolate. These idiomorphs were defined by the MAT1-1-1 or the MAT1-2-1 gene, respectively. A unique MAT1-1 idiomorph containing a truncated MAT1-2-1 gene, and a MAT1-1-1 gene, was identified in E. necatrix and E. fawcettii genomes. Additionally, two idiomorph-specific proteins were found in the MAT1-1 and MAT1-2 idiomorphs of E. australis. Universal mating-type markers confirmed heterothallism across 21 Elsinoe spp., are poised to advance future studies regarding the biology of these fungi.

Insights into Grape Ripe Rot: A Focus on the Colletotrichum gloeosporioides Species Complex and Its Management Strategies

Grape ripe rot, which is predominantly caused by the Colletotrichum species, presents a growing threat to global grape cultivation. This threat is amplified by the increasing populations of the Colletotrichum species in response to warmer climates. In this review, we investigate the wide-ranging spectrum of grape ripe rot, specifically highlighting the role and characteristics of the C. gloeosporioides species complex (CGSC). We incorporate this understanding as we explore the diverse symptoms that lead to infected grapevines, their intricate life cycle and epidemiology, and the escalating prevalence of C. viniferum in Asia and globally. Furthermore, we delve into numerous disease management strategies, both conventional and emerging, such as prevention and mitigation measures. These strategies include the examination of host resistances, beneficial cultivation practices, sanitation measures, microbiome health maintenance, fungicide choice and resistance, as well as integrated management approaches. This review seeks to enhance our understanding of this globally significant disease, aspiring to assist in the development and improvement of effective prevention and control strategies.

A cool climate perspective on grapevine breeding: climate change and sustainability are driving forces for changing varieties in a traditional market

A multitude of diverse breeding goals need to be combined in a new cultivar, which always forces to compromise. The biggest challenge grapevine breeders face is the extraordinarily complex trait of wine quality, which is the all-pervasive and most debated characteristic. Since the 1920s, Germany runs continuous grapevine breeding programmes. This continuity was the key to success and lead to various new cultivars on the market, so called PIWIs. Initially, introduced pests and diseases such as phylloxera, powdery and downy mildew were the driving forces for breeding. However, preconceptions about the wine quality of new resistant selections impeded the market introduction. These preconceptions are still echoing today and may be the reason in large parts of the viticultural community for: (1) ignoring substantial breeding progress, and (2) sticking to successful markets of well-known varietal wines or blends (e.g. Chardonnay, Cabernet Sauvignon, Riesling). New is the need to improve viticulture´s sustainability and to adapt to changing environmental conditions. Climate change with its extreme weather will impose the need for a change in cultivars in many wine growing regions. Therefore, a paradigm shift is knocking on the door: new varieties (PIWIs) versus traditional varieties for climate adapted and sustainable viticulture. However, it will be slow process and viticulture is politically well advised to pave the way to variety innovation. In contrast to the widely available PIWIs, competitive cultivars created by means of new breeding technologies (NBT, e.g. through CRISPR/Cas) are still decades from introduction to the market.

A Field Collection of Indigenous Grapevines as a Valuable Repository for Applied Research

The grapevine is an economically important plant, with a historical connection to the development of human culture. Currently, over 6000 accessions are known as individual grapevine varieties, some of which are important to national heritage, valuable for current viticultural practices, and as genetic resources to maintain plasticity under changing climatic conditions, environmental sustainability, and market demands. Recently, the diversity of cultivated grapevines has declined significantly, due to the increased focus of global wine industries on a few major cultivars. Moreover, due to biotic and abiotic stresses, the wild V. vinifera germplasm's genetic diversity has declined, with some varieties on the verge of extinction. Vitis germplasm conservation can be achieved via either in situ (e.g., protected areas) or Ex situ (e.g., field collections, seed banks, and tissue culture collections) methods. This study aims to highlight the importance of Vitis field bank collections. We demonstrate the research done in the Israeli indigenous Vitis vinifera collection. The multi-layer analysis of the varieties enabled the identification of drought stress-resistant varieties, and suggested a mechanism for this resistance through noting the dramatic phenological differences in foliage development between resistant and sensitive varieties. In addition, we show a general characterization of the varieties via major grape characteristics, including bunch and berry shape, as well as their possible utilization based on their aromatic and phenolic profiles.