Presence Of Fusarium Species Research Articles

Fusarium Species and Mycotoxins Associated with Sorghum Grains in Uruguay.

Grain mold and stalk rot are among the fungal diseases that cause significant losses in sorghum worldwide and are caused by different Fusarium spp. The presence of Fusarium species in sorghum grains causes yield losses and mycotoxin contamination, which represents a risk to consumers. In this study, Fusarium graminearum species complex (FGSC) had a high incidence, followed by Fusarium fujikuroi species complex (FFSC) and F. incarnatum-equiseti species complex. Within FFSC, F. proliferatum, F. andiyazi, F. fujikuroi, F. thapsinum, F. verticillioides and F. subglutinans were identified, and this was the first report of F. fujikuroi in sorghum. The most frequent toxins found in sorghum samples were deoxynivalenol (DON) and zearalenone (ZEN). The presence of fumonisins and nivalenol (NIV) was detected at low levels. This study adds new knowledge about the occurrence of Fusarium species and mycotoxins in sorghum grains. Furthermore, this is the first report in Uruguay on fungicide sensitivity for Fusarium isolates from sorghum, which constitutes an important starting point for defining management practices to minimize fungal infection and mycotoxin contamination.

Role of Sesamia nonagrioides and Ostrinia nubilalis as Vectors of Fusarium spp. and Contribution of Corn Borer-Resistant Bt Maize to Mycotoxin Reduction.

Maize expressing Cry1Ab insecticidal toxin (Bt maize) is an effective method to control Sesamia nonagrioides and Ostrinia nubilalis, the most damaging corn borers of southern Europe. In this area, maize is prone to Fusarium infections, which can produce mycotoxins that pose a serious risk to human and animal health, causing significant economic losses in the agrifood industry. To investigate the influence of corn borer damage on the presence of Fusarium species and their mycotoxins, Bt maize ears and insect-damaged ears of non-Bt maize were collected from commercial fields in three Bt maize growing areas in Spain, and differences in contamination were assessed. Additionally, larvae of both borer species were collected to evaluate their role as vectors of these molds. Non-Bt maize ears showed significantly higher presence of F. verticillioides, F. proliferatum, and F. subglutinans than Bt maize ears. For the first time, Fusarium species have been isolated from larvae of the two species. The most frequently found mycotoxins in ears were fumonisins, with non-Bt ears being significantly more contaminated than those of Bt maize. High levels of fumonisins were shown to correlate with the occurrence of corn borers in the ear and the presence of F. verticillioides and F. proliferatum.

Microbial Diversity in Cultivated and Feral Vanilla Vanilla planifolia Orchids Affected by Stem and Rot Disease

The worldwide production of vanilla, a native orchid from Mexico, is greatly affected by stem and root rot disease (SRD), typically associated with Fusarium oxysporum fungi. We hypothesized that the presence of Fusarium species in vanilla is not sufficient for the plant to express symptoms of the disease. We described the taxonomic composition of endophytic microbiomes in symptomatic and asymptomatic vanilla plants using 16S and ITS rDNA metabarcoding, and ITS Sanger sequences generated from fungal isolates. We compared the bacterial and fungal diversity in vanilla plants from a long-term plantation, and from feral plants found near abandoned plantations that did not present SRD symptoms. No significant differences were found in the species richness of the bacterial and fungal microbiome among feral, or asymptomatic and symptomatic cultivated vanilla. However, significant differences were detected in both fungal and bacterial diversity from different organs in the same plant, with roots being more diverse than stems. We found that Proteobacteria and Actinobacteria, as well as the fungal families Nectriaceae and Xylariaceae, constitute the core of the vanilla microbiome that inhabits the root and stem of both cultivated and feral plants. Our work provides information on the microbial diversity associated to root and stem rot in vanilla and lays the groundwork for a better understanding of the role of the microbiome in vanillafungal diseases.

Fusarium mycotoxin content andFusarium species presence in Czech organic and conventional wheat

Deoxynivalenol and zearalenone content and the presence ofFusarium species in organically and conventionally grown wheat harvested in the Czech Republic during 2015-2017 were studied. Mycotoxin contamination was compared using two approaches. The first was based on samples taken from randomly selected farms in individual regions of the Czech Republic, both organic (154 samples) and conventional (330 samples). In the second approach, a sample set of conventional wheat compatible with organic one was formed, with samples paired according to the preceding crop and region of harvest. Using the first approach, mycotoxins were shown to be higher in conventional wheat; however, there was no difference in mycotoxin contamination between organic and conventional wheat using the second approach. Eight wheat samples with mycotoxin content above the EU limits were found, seven for deoxynivalenol (2.1%) and one for zearalenone (0.3%), all of them originated from conventional farming system. Six of them had maize as the preceding crop. The presence of fiveFusarium species (Fusarium avenaceum, Fusarium culmorum, Fusarium graminearum, Fusarium poae andFusarium sporotrichioides) was compared for the compatible wheat sample sets (second approach). The predominant species were found to beF. poae andF. graminearum in both the organic and conventional wheat. Harvest year significantly influenced both the occurrence of the mainFusarium species and the level of mycotoxin contamination. The study confirmed that (a) organic farming system was able to keep mycotoxin contamination of wheat at a low level, (b) in studies on the significance of organic/conventional agricultural practice on mycotoxin levels in cereals, it is important to pay attention to common production and environmental variables.

The composition of Fusarium species in wheat husks and grains in south-eastern Poland

Fusarium populations were investigated on 53 samples of wheat grains and husks collected approximately three weeks before harvest in 53 wheat fields in south-eastern Poland. A limited area of sample collection was chosen intentionally to avoid the effect of climate and weather variability. The study was conducted to assess the occurrence of 13 Fusarium species using species-specific PCR assays separately on grains and husks of winter wheat. The obtained data suggest that husks could take a protective role of wheat grain against Fusarium spp. The incidence of Fusarium species decreased in grains vs. husks from 29 to 100%. While Fusarium species were present in husks at 11.32% and less, they were absent in the grain. The presence of Fusarium species on husks is inversely proportional to the percentage reduction of Fusarium spp. in grain. There was a correlation of the presence of certain species of Fusarium in husks and in grains. The number of Fusarium species found on husks was about three times higher in comparison to wheat grain. In conclusion, the presented data indicate the importance of Fusarium populations analysis on wheat husk in seeds pathological studies.

Presence of Fusarium Species and Other Toxigenic Fungi in Malting Barley and Multi-Mycotoxin Analysis by Liquid Chromatography-High-Resolution Mass Spectrometry.

A study was carried out on 43 malting barley samples collected in 2013 across the Umbria region (central Italy) to determine the incidence of the principal mycotoxigenic fungal genera, to identify the Fusarium species isolated from the grains, and to detect the presence of 34 fungal secondary metabolites by liquid chromatography-high-resolution mass spectrometry. The multimycotoxin-method development involved the evaluation of both a two-step solvent and QuEChERS protocol for metabolite extraction. The former protocol was selected because of better accuracy, which was evaluated on the basis of spike-recovery experiments. The most frequently isolated fungal species belonged to the genera Alternaria and Fusarium. The predominant Fusarium species was F. avenaceum, followed by F. graminearum. HT-2 toxin was the most frequently detected mycotoxin, followed by enniatin B, enniatin B1, T-2 toxin, and nivalenol. As a consequence of the observed mixed fungal infections, mycotoxin co-occurrence was also detected. A combination of mycological and mycotoxin analyses allowed the ability to obtain comprehensive information about the presence of mycotoxigenic fungi and their contaminants in malting barley cultivated in a specific geographic area.

Evolution of fungal populations in corn silage conserved under polyethylene or biodegradable films.

To identify cultivable filamentous fungi before ensiling, after silage conservation, in farm-silos covered with two different plastic films (polyethylene (PE) vs biodegradable (MB)), as well as after aerobic exposure of whole-crop corn silage. Molecular techniques coupled with traditional microbial counting were utilized to identify the predominant fungal species. The cultivable fungal population changed remarkably from harvesting to silo opening. Anaerobiosis and low pH reduced mould count and the presence of Fusarium species both under PE and MB film. However, in the peripheral areas of the silo, where air penetration could not be completely prevented, the fungal population did not decrease. The predominant fungal species after aerobic exposure of silage was Aspergillus fumigatus, without differences between the two plastic films. Maintenance of anaerobiosis and a low pH also in the upper layer of the silo reduce the risk of mould growth during corn silage feed-out. Even if the new MB plastic film did not completely maintain the anaerobiosis in the upper layer of silage, the overall silage quality was not compromised and was similar to that observed under PE, indicating that the development and use of MB film to cover silage is promising, but needs some improvement.

Impact of local pre-harvest management practices in maize on the occurrence of Fusarium species and associated mycotoxins in two agro-ecosystems in Tanzania

Knowledge on the presence of mycotoxins in Africa is fragmentary, although it can be assumed that both concentrations and prevalence in food commodities is high. The present study focuses on the presence of Fusarium species and their associated mycotoxins in maize from two geographically distant agro ecological systems in Tanzania. In a two-year survey, both Fusarium species and concomitant mycotoxins were surveyed in the Northern highlands (Hanang district) and the Eastern lowlands (Kilosa district). Parallel with this, a questionnaire on agricultural practices in both agro-ecosystems was included in this study. This allowed us to put the presence of the toxigenic Fusarium species and their mycotoxins within a relevant agricultural framework.Fusarium verticillioides, Fusarium graminearum and Fusarium poae were the predominant species in both locations although the population in the Eastern lowlands was slightly more complex comprising also Fusarium culmorum, Fusarium avenaceum and Fusarium sporotrichioides. The predominant presence of F. verticillioides resulted in a high prevalence of fumonisins in both regions. The importance of F. graminearum in the population was reflected by the presence of deoxynivalenol in the mycotoxin analysis. Although the agricultural practices differed significantly amongst both locations, only few significant correlations were detected between mycotoxin presence and crop rotation, storage conditions, and insect control measures.

Occurrence and distribution of soil Fusarium species under wheat crop in zero tillage

The presence of Fusarium species in cultivated soils is commonly associated with plant debris and plant roots. Fusarium species are also soil saprophytes. The aim of this study was to examine the occurrence and distribution of soil Fusarium spp. at different soil depths in a zero tillage system after the wheat was harvested. Soil samples were obtained at three depths (0-5 cm, 5-10 cm and 10-20 cm) from five crop rotations: I, conservationist agriculture (wheat-sorghum-soybean); II, mixed agriculture/livestock with pastures, without using winter or summer forages (wheat-sorghum-soybean-canola-pastures); III, winter agriculture in depth limited soils (wheat-canola-barley-late soybean); IV, mixed with annual forage (wheat-oat/Vicia-sunflower); V, intensive agriculture (wheat-barley-canola, with alternation of soybean or late soybean). One hundred twenty two isolates of Fusarium were obtained and identified as F. equiseti, F. merismoides, F. oxysporum, F. scirpi and F. solani. The most prevalent species was F. oxysporum, which was observed in all sequences and depths. The Tukey’s test showed that the relative frequency of F. oxysporum under intensive agricultural management was higher than in mixed traditional ones. The first 5 cm of soil showed statistically significant differences (p=0.05) with respect to 5-10 cm and 10-20 cm depths. The ANOVA test for the relative frequency of the other species as F. equiseti, F. merismoides, F. scirpi and F. solani, did not show statistically significant differences (p<0.05). We did not find significant differences (p<0.05) in the effect of crop rotations and depth on Shannon, Simpson indexes and species richness. Therefore we conclude that the different sequences and the sampling depth did not affect the alpha diversity of Fusarium community in this system.

Micronutrients and yield quality of pea (Pisum sativum L.) varieties susceptible to Fusarium oxysporum

The appearance of Fusarium species and the micronutrient content of pea varieties were investigated in different plant development periods. Field experiments were carried out for three years on six dry pea varieties grown without irrigation on a soil infected with Fusarium species. Green and dry plants divided into shoots (including stems and leaves), pods and seeds were used to determine the presence of Fusarium species and the concentration of micro- and macroelements. In the green shoots and seeds of varieties registered as susceptible to Fusarium oxysporum, other species such as F. solani and F. culmorum were also detected. F. oxysporum and F. solani were found in the dry seeds not only in varieties susceptible to F. oxysporum but in resistant ones as well. In the case of susceptible varieties the phosphorus and nickel contents in the flowering plants decreased significantly compared to those in varieties registered as resistant to F. oxysporum. In later stages of plant development the K and Mo contents increased significantly in the green shoots and the accumulation of Mn and Mo in the green seeds intensified. The very low B concentration in the dry pods contributed to the internal infection of dry seeds by decreasing the stability of the cell wall. In the dry seeds of varieties susceptible to F. oxysporum a considerable decrease in the S content was found parallel with marked increases in the Mo and Mn contents. The sugar content of green seeds decreased significantly in peas susceptible to F. oxysporum, but neither the protein, nor the starch or sugar contents of the dry seeds decreased in comparison to the resistant ones.

Toxicity and Occurrence of Fusarium species and Mycotoxins in Late Harvested and Overwintered Grain from Norway, 1993

AbstractSamples of grain, harvested in October/November of 1993 or in the spring of 1994 from fields in Norway with overwintered grain, were collected. The presence of Fusarium species and the amount of mycotoxins produced by this genus were determined. The cytotoxic properties of the grain samples were examined with an in vitro methylthiazoltetrazolium (MTT)‐cell culture assay using swine kidney and VERO cells as target cells. The total count of colony forming units of Fusarium species was about the same in the grain harvested in late autumn and in the spring, but the dominant species seemed to vary somewhat between the two groups. F. culmorum was found more in the samples from October/November while F. avenaceum was isolated more in the grain harvested in the spring. Only small amounts of F. sporotrichioides were present in the grain harvested in the autumn, and none was found in the overwintered grain. The deoxynivalenol content was significantly higher in the grain harvested in autumn than in the overwintered grain. Although very small amounts of toxins were detected in the overwintered grain, it was more cytotoxic than the grain harvested in October/November. A significant correlation between the cytotoxicity and the amount of F. avenaceum in the samples was found.