The status of Fusarium mycotoxins in Sub-Saharan Africa : a review of emerging trends and post-harvest mitigation strategies towards food control

Fusarium fungi are common plant pathogens causing several plant diseases. The presence of these molds in plants exposes crops to toxic secondary metabolites called Fusarium mycotoxins. The most studied Fusarium mycotoxins include fumonisins, zearalenone, and trichothecenes. Studies have highlighted the economic impact of mycotoxins produced by Fusarium. These arrays of toxins have been implicated as the causal agents of wide varieties of toxic health effects in humans and animals ranging from acute to chronic. Global surveillance of Fusarium mycotoxins has recorded significant progress in its control; however, little attention has been paid to Fusarium mycotoxins in sub-Saharan Africa, thus translating to limited occurrence data. In addition, legislative regulation is virtually non-existent. The emergence of modified Fusarium mycotoxins, which may contribute to additional toxic effects, worsens an already precarious situation. This review highlights the status of Fusarium mycotoxins in sub-Saharan Africa, the possible food processing mitigation strategies, as well as future perspectives

Fungal microbiota from rain water and pathogenicity of Fusarium species isolated from atmospheric dust and rainfall dust

In order to determine the presence of Fusarium spp. in atmospheric dust and rainfall dust, samples were collected during September 2007, and July, August, and October 2008. The results reveal the prevalence of airborne Fusarium species coming from the atmosphere of the South East coast of Spain. Five different Fusarium species were isolated from the settling dust: Fusarium oxysporum, F. solani, F. equiseti, F. dimerum, and F. proliferatum. Moreover, rainwater samples were obtained during significant rainfall events in January and February 2009. Using the dilution-plate method, 12 fungal genera were identified from these rainwater samples. Specific analyses of the rainwater revealed the presence of three species of Fusarium: F. oxysporum, F. proliferatum and F. equiseti. A total of 57 isolates of Fusarium spp. obtained from both rainwater and atmospheric rainfall dust sampling were inoculated onto melon (Cucumis melo L.) cv. Piñonet and tomato (Lycopersicon esculentum Mill.) cv. San Pedro. These species were chosen because they are the main herbaceous crops in Almeria province. The results presented in this work indicate strongly that spores or propagules of Fusarium are able to cross the continental barrier carried by winds from the Sahara (Africa) to crop or coastal lands in Europe. Results show differences in the pathogenicity of the isolates tested. Both hosts showed root rot when inoculated with different species of Fusarium, although fresh weight measurements did not bring any information about the pathogenicity. The findings presented above are strong indications that long-distance transmission of Fusarium propagules may occur. Diseases caused by species of Fusarium are common in these areas. They were in the past, and are still today, a problem for greenhouses crops in Almería, and many species have been listed as pathogens on agricultural crops in this region. Saharan air masses dominate the Mediterranean regions. The evidence of long distance dispersal of Fusarium spp. by atmospheric dust and rainwater together with their proved pathogenicity must be taken into account in epidemiological studies

Intracranial fusarium fungal abscess in an immunocompetent patient: case report and review of the literature.

Introduction Fusarium spp is an omnipresent fungal species that may lead to fatal infections in immunocompromised populations. Spontaneous intracranial infection by Fusarium spp in immunocompetent individuals is exceedingly rare. Case Report An immunocompetent 33-year-old Hispanic woman presented with persistent headaches and was found to have a contrast-enhancing mass in the left petrous apex and prepontine cistern. She underwent a subsequent craniotomy for biopsy and partial resection that revealed a Fusarium abscess. She had a left transient partial oculomotor palsy following the operation that resolved over the next few weeks. She was treated with long-term intravenous antifungal therapy and remained at her neurologic baseline 18 months following the intervention. Discussion To our knowledge, this is the first reported case of Fusarium spp brain abscess in an immunocompetent patient. Treatment options include surgical intervention and various antifungal medications. Conclusion This case demonstrates the rare potential of intracranial Fusarium infection in the immunocompetent host, as well as its successful treatment with surgical aspiration and antifungal therapy

The mutualistic fungus Piriformospora indica protects barley roots from a loss of antioxidant capacity caused by the necrotrophic pathogen Fusarium culmorum

Fusarium culmorum causes root rot in barley (Hordeum vulgare), resulting in severely reduced plant growth and yield. Pretreatment of roots with chlamydospores of the mutualistic root-colonizing basidiomycete Piriformospora indica (Agaricomycotina) prevented necrotization of root tissues and plant growth retardation commonly associated with Fusarium root rot. Quantification of Fusarium infections with a real-time PCR assay revealed a correlation between root rot symptoms and the relative amount of fungal DNA. Fusarium-infected roots showed reduced levels of ascorbate and glutathione (GSH), along with reduced activities of antioxidant enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR), and monodehydroascorbate reductase (MDHAR). Consistent with this, Fusarium-infected roots showed elevated levels of lipid hydroperoxides and decreased ratios of reduced to oxidized forms of ascorbate and glutathione. In clear contrast, roots treated with P. indica prior to inoculation with F. culmorum showed levels of ascorbate and GSH that were similar to controls. Likewise, lipid peroxidation and the overall reduction in antioxidant enzyme activities were largely attenuated by P. indica in roots challenged by F. culmorum. These results suggest that P. indica protects roots from necrotrophic pathogens at least partly, through activating the plant’s antioxidant capacity

Study and assessment of compost of different organic mixtures and effect of organic compost tea on plant diseases

Four compost treatments representing different organic mixtures were studied: - Treatment T1: 100% cattle manure - Treatment T2: 80% cattle manure and 20% sheep manure - Treatment T3: 70% cattle manure, 20% sheep manure and 10% poultry manure. - Treatment T4: 50% cattle manure, 20% sheep manure, 20% poultry manure and 10% crushed wheat straw. The results showed that the temperature was higher for the 4th treatment which was richer in carbon than the other treatments. The initial alkaline pH decreases for all treatments and approaches neutrality at the end of composting process, essentially for the first treatment. There is also a decrease in the carbon / nitrogen ratio. At the maturity stage, a compost tea was prepared from different composts after five days extraction period. The four compost teas were tested on different plant pathogens: Fusarium roseum var sambucinum, Fusarium oxysporum, Fusarium oxysporum, Fusarium solani var coeruleum, Phytophtora erythroseptica and Rhizoctonia solani. All the treatments were efficient against these pathogens and especially the 4th treatment which considerably reduces also the dry rot of Fusarium solani in potato tubers during storage. This is considered an important result since Fusarium solani seems to be the most important pathogen in Tunisian soils. Our studies should be carried out in order to determine the better combination of organic mixtures, the better method of compost tea extraction (aerobic or anaerobic), the optimal period of extraction and doses to be used

The potential of biological soil disinfestation to manage Fusarium foot and root rot in Asparagus

In a field experiment on an abandoned asparagus field we studied the effect of Biological Soil Disinfestation (BSD) on survival of buried inoculum samples of three test pathogens (Fusarium redolens f.sp. asparagi (FRA), Rhizoctonia tuliparum (RT) and Verticillium dahliae (VD)) and on the Fusarium infestation level. The BSD treatments involved incorporation of grass into moist soil and covering the soil with airtight plastic. The amount of grass incorporated was varied (42, 62 or 102 tons of grass/ha) as well as the depth of incorporation (40 or 80 cm). It was found that BSD greatly reduced all three pathogens in buried soil samples and that incorporation of 62 or 102 tons of grass per ha to 80 cm soil depth resulted in a significant decrease in soil infestation in the upper 40 cm; in the deeper layer the decrease was lower. Asparagus plants grown from seed in the field for one year showed a strong decrease in Fusarium root rot severity with all BSD treatments. The results clearly show the potential of BSD to decrease soil infestation levels of Fusarium pathogens and to contribute to an enhanced life span of replanted asparagus crop

Global distribution of two fungal pathogens threatening endangered sea turtles

This work was supported by grants of Ministerio de Ciencia e Innovación, Spain (CGL2009-10032, CGL2012-32934). J.M.S.R was supported by PhD fellowship of the CSIC (JAEPre 0901804). The Natural Environment Research Council and the Biotechnology and Biological Sciences Research Council supported P.V.W. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Thanks Machalilla National Park in Ecuador, Pacuare Nature Reserve in Costa Rica, Foundations Natura 2000 in Cape Verde and Equilibrio Azul in Ecuador, Dr. Jesus Muñoz, Dr. Ian Bell, Dr. Juan Patiño for help and technical support during samplingPeer reviewedPublisher PD

Basal rot of narcissus : understanding pathogenicity in fusarium oxysporum f. sp. narcissi

Fusarium oxysporum is a globally distributed soilborne fungal pathogen causing root rots, bulb rots, crown rots and vascular wilts on a range of horticultural plants. Pathogenic F. oxysporum isolates are highly host specific and are classified as formae speciales. Narcissus is an important ornamental crop and both the quality and yield of flowers and bulbs can be severely affected by a basal rot caused by F. oxysporum f. sp. narcissi (FON); 154 Fusarium isolates were obtained from different locations and Narcissus cultivars in the United Kingdom, representing a valuable resource. A subset of 30 F. oxysporum isolates were all found to be pathogenic and were therefore identified as FON. Molecular characterisation of isolates through sequencing of three housekeeping genes, suggested a monophyletic origin with little divergence. PCR detection of 14 Secreted in Xylem (SIX) genes, previously shown to be associated with pathogenicity in other F. oxysporum f. spp., revealed different complements of SIX7, SIX9, SIX10, SIX12 and SIX13 within FON isolates which may suggest a race structure. SIX gene sequences were unique to FON and SIX10 was present in all isolates, allowing for molecular identification of FON for the first time. The genome of a highly pathogenic isolate was sequenced and lineage specific (LS) regions identified which harboured putative effectors including the SIX genes. Real-time RT-PCR, showed that SIX genes and selected putative effectors were expressed in planta with many significantly upregulated during infection. This is the first study to characterise molecular variation in FON and provide an analysis of the FON genome. Identification of expressed genes potentially associated with virulence provides the basis for future functional studies and new targets for molecular diagnostics

An RNAi-Based Control of Fusarium graminearum Infections Through Spraying of Long dsRNAs Involves a Plant Passage and Is Controlled by the Fungal Silencing Machinery

Meeting the increasing food and energy demands of a growing population will require the development of ground-breaking strategies that promote sustainable plant production. Host-induced gene silencing has shown great potential for controlling pest and diseases in crop plants. However, while delivery of inhibitory noncoding double-stranded (ds)RNA by transgenic expression is a promising concept, it requires the generation of transgenic crop plants which may cause substantial delay for application strategies depending on the transformability and genetic stability of the crop plant species. Using the agronomically important barley—Fusarium graminearum pathosystem, we alternatively demonstrate that a spray application of a long noncoding dsRNA (791 nt CYP3-dsRNA), which targets the three fungal cytochrome P450 lanosterol C-14a-demethylases, required for biosynthesis of fungal ergosterol, inhibits fungal growth in the directly sprayed (local) as well as the non-sprayed (distal) parts of detached leaves. Unexpectedly, efficient spray-induced control of fungal infections in the distal tissue involved passage of CYP3-dsRNA via the plant vascular system and processing into small interfering (si)RNAs by fungal DICER-LIKE 1 (FgDCL-1) after uptake by the pathogen. We discuss important consequences of this new finding on future RNA-based disease control strategies. Given the ease of design, high specificity, and applicability to diverse pathogens, the use of target-specific dsRNA as an anti-fungal agent offers unprecedented potential as a new plant protection strategy