Beauvericin decreases cell viability of wheat.

Recently, beauvericin (BEA) has been recognized as an important toxic compound synthesized by several Fusarium strains, infecting maize, wheat, and rice, worldwide. The effects of BEA on mammalian cells have been studied; however, its effects on the function of host plant cells are largely unknown. The purpose of our work was to assess whether BEA can affect the root and leaf cells of wheat cultivar (cv.) 'Arina' seedlings, using a cytotoxicity assay and fluorescence microscopy. Toxigenicity during wheat germination was higher in BEA-treated wheat seedlings than in non-treated seedlings (control). Leaf primordial, situated at the base and the tips of treated leaves, were more affected by BEA compared to the control when assayed in medium for cell viability measured by luminescent equipment. BEA-Treated plant cells secrete adenosine triphosphate (ATP) to the extracellular matrix and invoke more luminescence by luciferase than the non-treated seedlings. Our results were confirmed by fluorescence microscopy following '4',6-diamidino-2-phenylindole' (DAPI) staining and by confocal microscopy. In addition, the bioluminescent protein luciferase was observed in the intracellular space indicating presence of ATP. The incidence of nuclear fragmentation increased significantly in cells of seedlings treated with BEA at 40 microM concentration implying that the intracellular phytotoxin BEA plays an important role, possibly as a mediator in cell-death signalling.

Yeast polysaccharide affects fusaric acid content in maize root rot.

Protective action of sulfoethyl glucan (SEG), a derivative of the cell wall glucan prepared from the baker's yeast Saccharomyces cerevisiae, was investigated in the maize seedlings infected by a plant pathogen Fusarium verticillioides (Sacc.). Several markers were assayed with the SEG addition and in the control experiments. Two evaluations were performed on the 7th and the 14th days. Addition of SEG led to the increased productivity parameters of the infected plants and maintained them at the level of non-infected plants during the 14 days of experiment. After seven days of cultivation, concentration of fusaric acid (=5-butylpyridine-2-carboxylic acid; FA) decreased in all infected plants cultivated in the presence of SEG when compared to that detected in the infected plants grown in the absence of SEG. After 14 days of cultivation, polysaccharide addition resulted in the reduction of FA concentration almost to 75% in comparison to the infected plants grown without polysaccharide addition. In the experiment, when exogenous FA was added to the growth medium, its concentration decreased up to 60% in the presence of SEG. Thus, it is feasible to assume that SEG binds and adsorbs FA, and, in this way, reduces its content and exerts protective action in plants against its toxic effect.

Penicillium strains isolated from Slovak grape berries taxonomy assessment by secondary metabolite profile.

The secondary metabolite profiles of microfungi of the genus Penicillium isolated from samples of grape berries collected in two different phases during two vegetative seasons in Slovakia is described to assess the taxonomy. Three Slovak vine regions have been selected for this study, based on their climatic differences and national economic importance. Cultures of microfungi isolated from berries were incubated on different selective media for macro and micromorphology identification. The species Penicillium brevicompactum, Penicillium crustosum, Penicillium chrysogenum, Penicillium expansum, Penicillium palitans and Penicillium polonicum were identified according to growth and morphology. The related strains were found to produce a broad spectrum of fungal metabolites, including roquefortine C, chaetoglobosin A, penitrem A, cyclopeptin, cyclopenin, viridicatin, methylviridicatin, verrucofortine, secalonic acid D, cyclopiazonic acid, fumigaclavine and mycophenolic acid. Chemotaxonomy was performed using high-performance liquid chromatography (HPLC) and mass spectrometry (MS). Dried grape berries were also analyzed allowing to assess the presence of patulin, roquefortine C and penicillic acid; this last one has been identified in dried berries but not in vitro.

Fusarium fungi and associated metabolites presence on grapes from Slovakia.

Toxinogenic Fusarium species were identified on grape berries from Slovak vineyards, and their toxic metabolites were analysed by HPLC-MS/MS. F. subglutinans, F. oxysporum, F. proliferatum, F. semitectum, F. solani, F. subglutinans, and F. verticillioides were found with varying frequency. F. oxysporum and F. proliferatum, cultured in vitro on Czapek yeast autolysate agar and yeast extract sucrose agar, produced beauvericin, in the range from 3,265 to 13,400 µg/kg, and fusaproliferin in high concentration, ranging from 49,850 to 259,500 µg/kg. A maximum value of 2.24 µg/kg has been observed for beauvericin in dried grape berries. Fumonisin B1, and fumonisin B2 were also identified, and the observed levels ranged from 500 to 2,040 µg/kg. Over 2 years (namely 2008 and 2009) many other metabolites have been identified and analysed in grape berries, in particular: avenacein Y, apicidin, aurofusarin, chlamydosporol, 2-amino-14,16-dimethyloctadecan-3-ol, enniatin A, enniatin A1, enniatin B2, enniatin B3, and equisetin.

Berries contamination by microfungi in Slovakia vineyard regions: impact of climate conditions on microfungi biodiversity.

BACKGROUND: Weather conditions can selectively promote the growth of particular fungal species, which cause rotting and spoilage of grape berries before harvest. The presence of pathogenic fungi can lead to the development of opportunist microfungi that can produce mycotoxins and cause grapes and wine contamination. OBJECTIVE: The variation of climatic conditions allowed to design a pilot study and address relevant questions for risk assessment of climate related mycotoxins production in grapes and in wine. METHODS: Microfungi contaminating berries during the vegetative period of year 2008 and 2009 in vineyards regions of Slovakia at the early veraison and at the ripening in harvest time have been identified. RESULTS: Spoilage fungi were more abundant in veraison for both years in all the studied geographical regions, with an average temperature of 20°C, humidity between 60 and 80%, and precipitation in the range 6-5mm. Much more strains of toxigenic fungi were found during veraison and ripening in the case of a year temperature variation in the range 17-22.5°C, humidity values ranging from 58 to 80% and precipitations in the range 0.7-8.4mm. CONCLUSIONS: The results suggest that there is an effect of the climatic conditions on microfungi biodiversity.