Occurrence and infection of Cladosporium, Fusarium, Epicoccum and Aureobasidium in withered rotten grapes during post-harvest dehydration

Identification and Pathogenicity of Cladosporium, Fusarium, and Diaporthe spp. Associated with Late-Season Bunch Rots of Grape

Fungal pathogens continue to pose a significant threat to grape production. Previous studies of pathogens associated with late-season bunch rots in Mid-Atlantic vineyards had elucidated the primary causal agents of these diseases, but the significance and identity of the less commonly isolated genera was unclear. Therefore, to more fully understand the identity and pathogenicity of Cladosporium, Fusarium, and Diaporthe spp. associated with late-season bunch rots of wine grapes in the Mid-Atlantic, phylogenic analyses and pathogenicity assays were conducted. Isolates were characterized to the species level by sequencing the TEF1 and Actin, TEF1 and TUB2, and TEF1 genes for 10, 7, and 9 isolates of Cladosporium, Diaporthe, and Fusarium, respectively. Four Cladosporium, three Fusarium, and three Diaporthe species were identified, and C. allicinum, C. perangustum, C. pseudocladosporioides, F. graminearum, and D. guangxiensis had not yet been isolated from grape in North America. The pathogenicity of each species was evaluated on detached table and wine grapes, and D. eres, D. ampelina, D. guangxiensis, and F. fujikuroi were found to be the most aggressive on both table and wine grapes. Further investigations through more extensive isolate collection and of myotoxicity testing may be warranted due to the prevalence and pathogenicity of D. eres and F. fujikuroi.

Induced Expression of CYP51a and HK1 Genes Associated with Penconazole and Fludioxonil Resistance in the Potato Pathogen Fusarium oxysporum

Preventing antifungal resistance development and identifying pathogens with high, medium, and low risk of resistance development to a particular fungicide or fungicide class is crucial in the fight against phytopathogens. We characterized the sensitivity of potato wilt-associated Fusarium oxysporum isolates to fludioxonil and penconazole and assessed the effect of these fungicides on the expression of fungal sterol-14-α-demethylase (CYP51a) and histidine kinase (HK1) genes. Penconazole stunted the growth of F. oxysporum strains at all concentrations used. While all isolates were susceptible to this fungicide, concentrations of up to 1.0 μg/mL were insufficient to cause a 50% inhibition. At low concentrations (0.63 and 1.25 μg/mL), fludioxonil stimulated growth in F. oxysporum. With an increase in the concentration of fludioxonil, only one strain (F. oxysporum S95) exhibited moderate sensitivity to the fungicide. Interaction of F. oxysporum with penconazole and fludioxonil leads to respective elevated expressions of the CYP51a and HK1 genes, which upsurge with increasing concentration of the fungicides. The data obtained indicate that fludioxonil may no longer be suitable for potato protection and its continuous use could only lead to an increased resistance with time.

Fusarium verticillioides of maize plant: Potentials of propitious phytomicrobiome as biocontrol agents

Disease outbreaks have been recorded due to exposure to Fusarium verticillioides and fumonisin, a mycotoxin produced by this fungus. F. verticillioides is a fungal pathogen of maize that causes infections, such as wilting and rotting, while contact with its fumonisin derivative manifests in the form of mild to severe illnesses in humans and animals. Maize infection by F. verticillioides causes loss or reduction in expected crop yield, thereby influencing households and nations' economies. While several efforts have been made to control the pathogenic fungus and its occurrence in the environment, it remains a challenge in agriculture, particularly in maize production. Several microorganisms which are plant-associated, especially those associated with the rhizosphere niche have been noted to possess antagonistic effects against F. verticillioides. They can inhibit the pathogen and tackle its debilitating effects on plants. Hence this study reviews the use of rhizosphere-associated biocontrol agents, such as Bacillus spp., Pseudomonas, Enterobacter, and Microbacterium oleivorans which forms part of the phytomicrobiome in other to prevent and control this toxicogenic fungus. These microorganisms were found to not only be effective in controlling its occurrence on maize plants but are environmentally safe and promote crop yield.

Improvement of beauvericin production by Fusarium oxysporum AB2 under solid-state fermentation using an optimised liquid medium and co-cultures

The production of beauvericin (BEA) by Fusarium oxysporum AB2 in liquid medium (SmF) was compared to that on solid medium (SSF) on inert support (polyurethane foam or PUF), using a previously optimised medium. The analysis included two different concentrations of the medium (1 × and 3 ×). Under SSF, the production of BEA (22.8 mg·L^-1) was higher relative to SmF (0.8 mg·L^-1). The production increased proportionally in the concentrated medium (3 ×) (65.3 mg·L^-1); using the concentrated medium in SmF, the production of BEA was completely inhibited, although more biomass was produced. The peak of BEA production was reached on day 7 and remained stable until day 11; sustained production after several days has not been achieved in similar reports. The presence of BEA was corroborated by high-performance liquid chromatography (HPLC) and mass spectrometry. The BEA production profile is shown performing mixed cultures of Fusarium oxysporum AB2 and Epicoccum nigrum TORT using the same system, increasing the production of BEA up to 84.6 mg·L^-1. We propose SSF using polyurethane foam (PUF) as a solid support as a new culture system for obtaining secondary metabolites such as BEA.

The Content of Selected Bioactive Compounds in Wines Produced from Dehydrated Grapes of the Hybrid Variety ‘Hibernal’ as a Factor Determining the Method of Producing Straw Wines

Sweet wines are appreciated worldwide; many are produced by fermenting the must of dehydrated (semi-dried) grapes, using methods that vary from region to region. The aim of this study was to evaluate the basic chemical and oenological characteristics of wines obtained by three technologies of production. The wines were made from a hybrid cultivar ‘Hibernal’, grown under cool climate conditions. ‘Hibernal’ is a hybrid variety. This ‘Hibernal’ variety is widely cultivated in central and eastern Europe, where it is of great economic importance. Wines produced from this variety are popular in local markets. In comparison with the production of varieties belonging to Vitis vinifera, a very small percentage of the ‘Hibernal’ variety is cultivated. The methods used in the experiment for the production of wines were: classical method in the Italian passito style, modification of the passito style with a seven-day maceration of grapes, and a method of production in the Tokaj wine style at five Puttonyos. Basic chemical parameters, acid profile, total phenolic content, antioxidant and antiradical capacities, and quantitative analysis of selected polyphenols was performed. The sensory features and quality of the wines was assessed using a sommelier analysis based on The Wine & Spirit Education Trust guidelines. The results indicated that the seven-day maceration of the dehydrated grapes resulted in the highest polyphenol content, as well as the largest antioxidant and antiradical contents. The oenological evaluation of wines produced by the Tokaj method and Italian passito method with seven-day maceration found that the wines were appreciated due to their rich taste, flavor, and overall quality. The present study confirms the promising opportunities to obtain special sweet wine with a valuable composition and oenological characteristics in regions with cooler climates.

Diversity and Drug Resistance of Filamentous Fungi Isolated from the Fresh Raspberries

Fungi are one of the most widely distributed microorganisms in the environment, including food such as fruits, vegetables and other crops, posing a potential threat to food safety and human health. The aim of this study was to determine the diversity, intensity and drug resistance of potentially pathogenic filamentous fungi isolated from the fresh raspberries (Rubus idaeus L.). A total of 50 strains belonging to genera Fusarium, Cladosporium, Alternaria, Penicillium, Mucor, Rhizopus, Aspergillus and Acremonium were tested for drug resistance against 11 antifungals by disc diffusion and gradient strips methods. The average mycological contamination in the examined samples of raspberries amounted to 4.34 log CFU/g. The Cladosporium was isolated from all tested samples, followed by Alternaria and Fusarium with a frequency of 61% and 34%, respectively. The highest level of drug resistance was observed for Acremonium genera and Fusarium strains recorded a wide variation in drug resistance as revealed by susceptibility with amphotericin B and voriconzole with MICs ranged from 0.5–4 µg/ml and posaconazole with MICs ranging from 3–8 µg/ml. All fungal strains showed 100% resistance to caspofungin, fluconazole and flucytosine with both the methods, and 100% resistance to micafungin and anidulafungin in the gradient strip method.

Exogenous Probiotics Improve Fermentation Quality, Microflora Phenotypes, and Trophic Modes of Fermented Vegetable Waste for Animal Feed

The fermentation of leaf vegetable waste to produce animal feed reduces the environmental impact of vegetable production and transforms leaf vegetable waste into a commodity. We investigated the effect of exogenous probiotics and lignocellulose enzymes on the quality and microbial community of fermented feed (FF) produced from cabbage waste. The addition of exogenous probiotics resulted in increased crude protein (CP) content (p < 0.05), better odor (moderate organic acid and ethanol, with low ammonia-N, p < 0.05), and a lower relative abundance (RA) of pathogens (below 0.4%, p < 0.05) in FF, compared to without. With the addition of exogenous probiotics, only Pediococcus and Saccharomyces were enriched and symbiotic in FF; these were the keystone taxa to reduce the abundance of aerobic, form-biofilms, and pathogenic microorganisms, resulting in an efficient anaerobic fermentation system characterized by facultative anaerobic and Gram-positive bacterial communities, and undefined saprotroph fungal communities. Thus, inoculation of vegetable waste fermentation with exogenous probiotics is a promising strategy to enhance the biotransformation of vegetable waste into animal feed.

Macroalgae Derived Fungi Have High Abilities to Degrade Algal Polymers

Marine fungi associated with macroalgae are an ecologically important group that have a strong potential for industrial applications. In this study, twenty-two marine fungi isolated from the brown seaweed Fucus sp. were examined for their abilities to produce algal and plant biomass degrading enzymes. Growth of these isolates on brown and green algal biomass revealed a good growth, but no preference for any specific algae. Based on the analysis of enzymatic activities, macroalgae derived fungi were able to produce algae specific and (hemi-)cellulose degrading enzymes both on algal and plant biomass. However, the production of algae specific activities was lower than the production of cellulases and xylanases. These data revealed the presence of different enzymatic approaches for the degradation of algal biomass by macroalgae derived fungi. In addition, the results of the present study indicate our poor understanding of the enzymes involved in algal biomass degradation and the mechanisms of algal carbon source utilization by marine derived fungi.

Fungal Systematics and Evolution: FUSE 5

Thirteen new species are formally described: Cortinarius brunneocarpus from Pakistan, C. lilacinoarmillatus from India, Curvularia khuzestanica on Atriplex lentiformis from Iran, Gloeocantharellus neoechinosporus from China, Laboulbenia bernaliana on species of Apenes, Apristus, and Philophuga (Coleoptera, Carabidae) from Nicaragua and Panama, L. oioveliicola on Oiovelia machadoi (Hemiptera, Veliidae) from Brazil, L. termiticola on Macrotermes subhyalinus (Blattodea, Termitidae) from the DR Congo, Pluteus cutefractus from Slovenia, Rhizoglomus variabile from Peru, Russula phloginea from China, Stagonosporopsis flacciduvarum on Vitis vinifera from Italy, Strobilomyces huangshanensis from China, Uromyces klotzschianus on Rumex dentatus subsp. klotzschianus from Pakistan. The following new records are reported: Alternaria calendulae on Calendula officinalis from India; A. tenuissima on apple and quince fruits from Iran; Candelariella oleaginescens from Turkey; Didymella americana and D. calidophila on Vitis vinifera from Italy; Lasiodiplodia theobromae causing tip blight of Dianella tasmanica 'variegata' from India; Marasmiellus subpruinosus from Madeira, Portugal, new for Macaronesia and Africa; Mycena albidolilacea, M. tenuispinosa, and M. xantholeuca from Russia; Neonectria neomacrospora on Madhuca longifolia from India; Nothophoma quercina on Vitis vinifera from Italy; Plagiosphaera immersa on Urtica dioica from Austria; Rinodina sicula from Turkey; Sphaerosporium lignatile from Wisconsin, USA; and Verrucaria murina from Turkey. Multi-locus analysis of ITS, LSU, rpb1, tef1 sequences revealed that P. immersa, commonly classified within Gnomoniaceae (Diaporthales) or as Sordariomycetes incertae sedis, belongs to Magnaporthaceae (Magnaporthales). Analysis of a six-locus Ascomycota-wide dataset including SSU and LSU sequences of S. lignatile revealed that this species, currently in Ascomycota incertae sedis, belongs to Pyronemataceae (Pezizomycetes, Pezizales).

Microscopic fungi isolated from different Slovak grape varieties

The aim of this study was to isolate and identify microscopic fungi in different grape samples. We collected 13 grapes varienties samples (9 white and 4 red) from local Slovak winemakers in the end of the September 2017. Used 13 grape samples in this study: Alibernet, Irsai Oliver, Dornfelder, Blue Frankish, Feteasca regala, Green Veltliner, Pálava, Mūller Thurgau, Rhinriesling, Cabernet Savignon, Pinot Blanc, Savignon Blanc and Welschriesling. Microscopic fungi in grape samples were detected on Malt extract agar by spread plate method. The number of microscopic fungi ranged from 2.85 log cfu.g-1 in Cabernet Savignon to 4.83 log cfu.g-1 in Feteasca regala. A total of 627 isolates of microscopic fungi were obtained in this study. The most abundant fungi belonged to genera Alternaria and Penicillium (100% frequency). The high frequency was also detected for Aspergillus (76.92%) and Cladosporium (76.92%) but with lesser relative density. Alternaria sp., Aspergillus niger, Aspergillus sp., Botrytis cinerea, Cladosporium sp., Penicillium expansum, Phoma sp., Rhizopus sp. and Trichoderma sp. species were isolated from grape berries.

Predominant mycotoxins, mycotoxigenic fungi and climate change related to wine

Wine is a significant contributor to the economies of many countries. However, the commodity can become contaminated with mycotoxins produced by certain fungi. Most information on mycotoxins in wine is from Spain, Italy and France. Grapes can be infected by mycotoxigenic fungi, of which Aspergillus carbonarius producing ochratoxin A (OTA) is of highest concern. Climate is the most important factor in determining contamination once the fungi are established, with high temperatures being a major factor for OTA contamination: OTA in wine is at higher concentrations in warmer southern Europe than northern. Contamination by fumonisins is a particular concern, related to Aspergillus niger producing these compounds and the fungus being isolated frequently from grapes. Aflatoxins can be present in wine, but patulin is seldom detected. Alternaria mycotoxins (e.g. alternariol) have been frequently observed. There are indications that T-2 toxin may be common. Also, the combined effects of mycotoxins in wine require consideration. No other mycotoxins are currently of concern. Accurate fungal identifications and mycotoxin detection from the fungi are important and a consideration of practical methods are required. There is a diversity of wines that can be contaminated (e.g. red, white, sweet, dry and fortified). The occurrence of OTA is higher in red and sweet than white wines. Steps to control mycotoxins in wine involve good agriculture practices. The effect of climate change on vines and mycotoxins in wine needs urgent consideration by well-constructed modelling studies and expert interpretation of existing data. Reliable models of the effect of climate change on vines is a priority: the health of vines affects mycotoxin contamination. A modelling study of OTA in grapes at higher temperatures over 100years is required. Progress has been made in reducing OTA in wine. The other mycotoxins require consideration and the effects of climate change will become crucial.

Species of genera Botrytis, Fusarium and Rhizopus on grapes of the Slovak origin

Our research was focused to identify the Botrytis, Fusarium and Rhizopus species from grapes of the Slovak origin. A further goal of the project was to characterized toxinogenic potential of chosen strains of species Fusarium. 50 samples of grapes, harvested in years 2011, 2012 and 2013 from various wine-growing regions were analyzed in this study. For the isolation of species the of direct plating method was used: a) surface-sterilized berries (using 1% freshly pre-pared chlorine) b) berries and c) damaged berries on DRBC (Dichloran Rose Bengal Chloramphenicol agar). For each analysis were used 50 berries (or all damaged berries from sample). The cultivation was carried at 25 ±1°C, for 5 to 7 days in dark. After incubation, the colonies of Botrytis, Fusarium and Rhizopus were transferred to identification media and after incubation strains were identified to species level.  Thirteen species of fusaria (F. acuminatum, F. avenaceum, F. culmorum, F. equiseti, F. graminearum, F. oxysporum, F. proliferatum, F. semitectum, F. solani, F. sporotrichioides, F. subglutinans F. tricinctum and F. verticilioides) were identified. Frequency of fusaria isolation was 92 %. Botrytis cinerea was determined from 86% samples and Rhizopus from 94%. Chosen strains of species of genus Fusarium were able to produce following mycotoxins: deoxynivalenol, T-2 toxin, HT-2 toxin and diacetoxyscirpenol in in vitro conditions as determinated by thin-layer chromatography. Thirty-two (68%) of tested isolates of Fusarium species were able to produce at least one mycotoxin.