Fumonisin Content Research Articles

Hydrogen cyanide and mycotoxins: Their incidence and dietary exposure from cassava products in Anyigba, Nigeria

While cassava products are important in addressing food security crises in Africa, they are not exempted from recurring food safety concerns. This research determined consumption, incidence, and concentrations of hydrogen cyanide (HCN), total aflatoxins (AFs), ochratoxin A (OTA) and fumonisins (FBs) in cassava product (casava flour, fufu and gari) among residents of Anyigba, Nigeria, and also estimated dietary exposure to the toxins from the foods. Consumption data from 82 households showed that 89%, 68% and 94% of the residents consume cassava flour, fufu, and gari, respectively. Average daily intake for individuals was 0.751, 0.111, and 0.120 kg of cassava flour, fufu, and gari respectively. The highest incidence and concentration of HCN were found in cassava flour, with %TDI (EDI) of 33.3% (0.03 mg/kg.bw/day). Weekly, residents are exposed to 0.0371, 0.0077 and 0.0224 μg/kg.bw of OTA, and daily to 0.0315, 0.0043, 0.0060 μg/kg.bw of AFs and 0.0000, 0.0025, 0.0004 μg/kg.bw of FBs from consumption of cassava flour, fufu, and gari, respectively. The mycotoxins also co-occurred in the food products.

Analysis of preharvest meteorological conditions in relation to concentration of fumonisins in kernels of two genetically different maize hybrids

The effects of meteorological conditions around silking (Si) and physiological maturity (PM) on production of fumonisins (FB=FB1 + FB2) in maize kernels were analyzed. Kernel FB contents were determined on kernel samples collected from an experimental susceptible hybrid (n = 35) and a Bt commercial hybrid (n = 23) planted in several growing seasons/sites from the Argentinean Pampas. Considering the effect of genetic divergence of the two maize hybrids, total kernel FB concentrations (n = 52) binary coded, were predicted appropriately by weather-based logistic regression models but underestimated in some samples severely contaminated with FB. After removing these misclassified cases that registered maximum values of a drought-heat stress index (DI) calculated over 30 days around Si, and weather conditions (assessed by weather interactive components) conducive to infection/production of FB in PM, new logistic models were fitted. These new models improved their predictive ability indices. It was remarkable a model including the discrete genetic variable and the weather variable associated with the simultaneous occurrence of precipitation, temperature between 19.5–33 °C and relative humidity >70%, required for fungal infection in Si. Models that also included weather variables calculated in PM and associated with the kernel drying rate and fungal infection, did not result in better prediction outcomes. Opposite to the general trend, the occurrence of both severe heat-drought stress around Si and favorable weather around PM led to high kernel FB contents. We hypothesize that husk shortening by stress at silking might expose ears, promoting Fusarium verticillioides colonization/FB synthesis in late stages of kernel development and maturity, whenever favorable environmental conditions for both processes prevail.

Effects of Fumonisin-Contaminated Corn on Growth Performance of 9 to 28 kg Nursery Pigs.

Fumonisin contamination in corn is an emerging issue in animal feed production. Fumonisin disrupts the metabolism of sphingolipids and reduces growth performance. This experiment was conducted to determine the effect of feeding fumonisin-contaminated corn on growth performance and sphinganine (SA) to sphingosine (SO) ratios of 9 to 28 kg pigs. A total of 350 pigs, were used with 5 pigs/pen and 14 pens/treatment. Dietary treatments contained fumonisin-contaminated corn (50 mg/kg of fumonisin B1 + B2) blended with low fumonisin corn (10 mg/kg of fumonisin B1 + B2) to provide dietary fumonisin concentrations of 7.2, 14.7, 21.9, 32.7, and 35.1 mg/kg. From day 0 to 28, increasing fumonisin concentration decreased (linear, p < 0.001) average daily gain, average daily feed intake (linear, p = 0.055), and gain:feed ratio (linear, p = 0.016). Although these response criteria tested linear, the greatest reduction in performance was in pigs fed with 32.7 and 35.1 mg/kg of fumonisin (B1 + B2). Increasing fumonisin concentration increased the serum SA:SO ratio (linear, p < 0.001) on day 14 and 28. In summary, for 9 to 28 kg nursery pigs, increasing fumonisin linearly decreased average daily gain and gain:feed ratio. However, despite the linear response, diets containing up to 21.9 mg/kg of fumonisin did not have as dramatic a decrease in growth performance as those fed more than 32.7 mg/kg. Further research is warranted to determine the effect of fumonisin concentrations between 21.9 and 32.7 mg/kg.

Detection and Determination of Fumonisins B1, B2, and B3 Contaminating Japanese Domestic Wine by Liquid Chromatography Coupled to Tandem Mass Spectrometry (LC-MS/MS).

Nine domestic wine samples collected from a Japanese winery were examined for the presence of fumonisin B1 (FB1), fumonisin B2 (FB2), and fumonisin B3 (FB3), as well as ochratoxin A (OTA) and ochratoxin B (OTB). Wine samples spiked with 13C-labeled internal standards (13C34-FB1 and 13C20-OTA) were diluted with phosphate buffered saline (PBS) buffer, loaded on immunoaffinity cartridges to purify of fumonisins and ochratoxins, and subjected to liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis. The data revealed that the domestic wine samples were possibly contaminated with FB1 and FB3, in addition to FB2, whereas none of the tested wine samples were contaminated with OTA and OTB. These results suggest that Fusarium fungi can be associated with the fumonisin contamination of Japanese domestic wine, whereas Aspergillus niger seems to be frequently reported as the major causal fungus of fumonisin contamination of wine in Europe. Analysis of the intermediate samples during the wine brewing indicated that fumonisin concentrations did not increase during wine production, suggesting that fumonisin contamination did not occur during the brewing process, but was derived from the raw materials of grape berries.

Safety and efficacy of fumonisin esterase from Komagataella phaffii DSM 32159 as a feed additive for all animal species.

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of fumonisin esterase from Komagataella phaffii DSM 32159 as a technological feed additive for all animal species. The product has been already assessed by the FEEDAP Panel for use in pigs and poultry feed as technological additive and was granted with an authorisation in the EU for this use. In the current application, the additive is intended to be used in fermenting feeds with the purpose to reduce the contamination of feed by fumonisins. New data provided showed that no recombinant DNA could be detected in three batches of the product. The evidence provided – based on the data submitted in the previous and the current application – allowed the FEEDAP Panel to conclude that the additive is safe for the target animals under the proposed conditions of use. The Panel also considered valid the previous conclusions in which the safety of the additive for consumers and the environment was established. The additive is not toxic by inhalation and the respiratory exposure is likely to be low; however, a risk of sensitisation via the respiratory route cannot be excluded. The additive is non‐irritant to skin and eyes and is not considered as a dermal sensitiser. The additive has the capacity to degrade fumonisins in fermenting feed (with a fumonisin content within the guidance limits operating in the EU) when used at the minimum recommended dose of 40 U/kg feed. The FEEDAP Panel notes that the efficacy has been demonstrated only in silages, not in other fermenting feeds like e.g. liquid feeds.

Microbiome-guided evaluation of Bacillus subtilis BIOUFLA2 application to reduce mycotoxins in maize kernels

Fungal diseases are aggravating globally in crop cultivation despite of growing inputs of chemical fungicides. Ear rot and fumonisin contamination of kernels caused by Fusarium verticillioides lead to qualitative and quantitative reductions in maize production. In tropical agriculture, high yielding maize currently can only be assured through foliar protection using fungicides due to the high pathogen pressure. However, the use of chemical fungicides alone does not guarantee the protection of kernels. Recently, a tandem application of fungicides with the Bacillus subtilis strain BIOUFLA2 was identified as a promising strategy to control F. verticillioides-caused diseases. We have employed an integrative approach to assess changes in the microbiome of maize subjected to a combination of chemical and biological fungicides and contrasted it to conventional treatments. This was complemented with molecular and analytical monitoring of the pathogen and mycotoxin levels. Two sampling times were included (10 days after application of treatments and upon harvesting) and two maize fields to account for regional differences. A comparative analysis indicated a treatment-specific enrichment of bacterial and fungal OTUs (Operational Taxonomic Units) that were not detectable in the maize microbiome of untreated plants. Both, the chemical and the tandem application of a chemical and biological pesticide resulted in the occurrence of unique OTUs. Samples subjected to these treatments harbored up to 22 additional OTUs. The lowest fumonisin concentration was observed in the treatment that encompassed BIOUFLA2 (field 1 = 0.29 ppm and field 2 = 0.77 ppm), while the conventional fungicide application resulted in the highest mycotoxin concentrations (field 1 = 3.84 ppm and field 2 = 10.02 ppm). Our study provided strong evidence that conventional treatments of maize with fungicides can promote mycotoxin levels in grains and that partial replacement with biologicals can increase the treatment efficiency.

Occurrence ofFusarium mycotoxins and toxigenicFusarium species in freshly harvested rice in Jiangsu, China

In 2017, 236 rice samples were collected from 42 counties in Jiangsu province, China, and analysed forFusarium mycotoxins. Mycotoxin analyses showed that deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-ADON), 15-acetyldeoxynivalenol (15-ADON), nivalenol (NIV), fusarenone X (FUS-X), zearalenone (ZEA), fumonisins (including FB1, FB2, and FB3), and beauvericin (BEA) were present in unhusked rice samples. Regional differences in mycotoxin contamination of unhusked rice were attributed to differences in precipitation during rice anthesis and agricultural practices among the three study regions. Importantly, the mean concentrations of DON, NIV, ZEA, and fumonisins in white rice were significantly lower than those in unhusked rice, and the relative proportion of the toxins in rice by-products exceeded 84%.Fusarium isolates were then obtained from the unhusked rice samples;Fusarium asiaticum was the most common, followed byFusarium fujikuroi, Fusarium proliferatum, Fusarium verticillioides, andFusarium commune. Genotype and chemical analyses of mycotoxins showed that mostF. asiaticum isolates (71%) were 3-ADON chemotypes; the remainder were NIV producers. All of theF. proliferatum andF. verticillioides isolates, and most of theF. fujikuroi isolates produce fumonisins, and most of the three species coproduced BEA. The present study is the first to evaluateFusarium mycotoxins and toxigenicFusarium species from rice freshly harvested in Jiangsu province, China. The results of this study improve our understanding the population dynamics ofFusarium species in rice and the development of effective control measures.

Investigation of fumonisin interaction with maize macrocomponents and its bioaccessibility from porridge using the dynamic tiny-TIM gastrointestinal model

Contamination of maize by fumonisin mycotoxins is of major concern to consumer health. This study was designed to improve our understanding of the binding of fumonisin B (FB) to maize and its major macrocomponents, during the preparation of porridge. None of the processing treatments (pH 4, 7 and 10) or temperatures (30 and 90 °C) used resulted in a significant decrease in the recovery of FB1 from spiked starch, zein or maize meal. These results confirm the stability of FB1 in maize porridge, and the absence of modified forms of FB. The bioaccessibility of fumonisins in the gastrointestinal tract, following consumption of contaminated stiff maize porridge, was determined using the TNO Gastrointestinal Model (tiny-TIM). The porridge was digested in the tiny-TIM using parameters simulating human digestion. The concentrations of fumonisins were determined in the dialysates at fixed time intervals using ultra performance liquid chromatography-quadrupole Time-of-Flight high definition mass spectrometry (UPLC-QToF-HDMS). The results proved that fumonisins B1, B2 and B3 are released rapidly from stiff porridge prepared from contaminated maize meal. This confirms that the low bioavailability of fumonisins cannot be attributed to strong association of the toxin with the intestinal content. This study presents new insights into the stability of fumonisins in maize porridge and the kinetics of fumonisin-release from porridge through simulated human digestion, suggesting that consumers using maize as a staple may be at risk.

Free and hidden fumonisins in Argentinean raw maize samples

The concentrations of free fumonisins (FBs) and hydrolysed fumonisins (HFBs) were determined in 72 maize samples collected in 2017 from five Argentine provinces. The methodology for HFBs analysis consisted of alkaline hydrolysis followed by high performance liquid chromatography with a fluorescence detector (HPLC-FLD). The developed analytical methodology presented percentages of recovery greater than 74%. Limits of detection were 4.5, 13.0 and 12.9 μg/kg for HFB1, HFB2 and HFB3, respectively. Presence of FBs was found in 86% of the samples. In all cases, the concentration of total HFBs (after the hydrolysis treatment) was superior to the free FBs content (HFBs to FBs median ratio of 2.5), which indicates the presence of hidden fumonisins in Argentinean maize. 8% of the traditionally analysed samples exceeded the limit established by the European Commission for FB1 + FB2. When applying alkaline hydrolysis to the samples, 24% of them exceed this limit.

Occurrence and Co-Occurrence of Mycotoxins in Cereal-Based Feed and Food.

Dietary (co)-exposure to mycotoxins is associated with human and animal health concerns as well as economic losses. This study aims to give a data-based insight from the scientific literature on the (co-)occurrence of mycotoxins (i.e., parent and modified forms) in European core cereals, and to estimate potential patterns of co-exposure in humans and animals. Mycotoxins were mainly reported in wheat and maize showing the highest concentrations of fumonisins (FBs), deoxynivalenol (DON), aflatoxins (AFs), and zearalenone (ZEN). The maximum concentrations of FB1+FB2 were reported in maize both in feed and food and were above legal maximum levels (MLs). Similar results were observed in DON-food, whose max concentrations in wheat, barley, maize, and oat exceeded the MLs. Co-occurrence was reported in 54.9% of total records, meaning that they were co-contaminated with at least two mycotoxins. In the context of parental mycotoxins, co-occurrence of DON was frequently observed with FBs in maize and ZEN in wheat; DON + NIV and DON + T2/HT2 were frequently reported in barley and oat, respectively. Apart from the occurrence of ZEN and its phase I and phase II modified forms, only a limited number of quantified data were available for other modified forms; i.e., mainly the acetyl derivatives of DON. Data gaps are highlighted together with the need for monitoring studies on multiple mycotoxins to identify co-occurrence patterns for parent mycotoxins, metabolites, and their modified forms.

Selected isolates of Trichoderma gamsii induce different pathways of systemic resistance in maize upon Fusarium verticillioides challenge

The pink ear rot is one of the most damaging maize diseases, caused by the mycotoxigenic fungal pathogen, Fusarium verticillioides. The application of biological control agents, like antagonistic and/or resistance inducer microorganisms, is an option to reduce fungal infection and kernel contamination in a sustainable and environmentally friendly way. It is well known that Trichoderma species are non-pathogenic fungi able to antagonize plant pathogens and to induce systemic resistance in plants. The present work aimed to verify if Trichoderma spp., applied to maize kernels, affect the plant growth and induce systemic responses to F. verticillioides. Besides, the capability to reduce fumonisin concentration in liquid cultures was investigated. Two T. gamsii (IMO5 and B21), and one T. afroharzianum (B75) isolates, selected both for antagonism and for the ability to reduce root infections, significantly reduced the endophytic development of the stem-inoculated pathogen, compared to the control. The mechanisms of action appeared to be strain-specific, with IMO5 enhancing transcript levels of marker genes of Induced Systemic Resistance (ZmLOX10, ZmAOS, and ZmHPL) while B21 enhancing marker genes of Systemic Acquired Resistance (ZmPR1 and ZmPR5), as evinced by measuring their expression profiles in the leaves. Moreover, IMO5 promoted plant growth, while B21 was able to significantly reduce the fumonisin content in a liquid medium. The results of this work give new evidence that the seed application of T. gamsii is a promising tool for controlling F. verticillioides to be integrated with breeding and the adoption of good agricultural practices.

Occurrence and Risk Assessment of Fumonisin B1 and B2 Mycotoxins in Maize-Based Food Products in Hungary.

Fumonisins are toxic secondary metabolites produced mainly by Fusarium verticillioides and Fusarium proliferatum. Their toxicity was evaluated, and health-based guidance values established on the basis of both Joint FAO/WHO Expert Committee on Food Additives (JECFA) and European Food Safety Authority (EFSA) recommendations. This study presents the results of fumonisin analyses in different maize- and rice-based food products in Hungary and the potential health risk arising from their dietary intake. In total, 326 samples were measured in 2017 and 2018 to determine fumonisins B1 and B2 levels. Three-day dietary record data were collected from 4992 consumers, in 2009. For each food category, the average concentration values were multiplied by the relevant individual consumption data, and the results were compared to the reference values. With respect to the maximum limits, one maize flour, two maize grits, and two samples of other maize-based, snack-like products had total fumonisin content minimally exceeding the EU regulatory limit. The mean daily intake for all maize-product consumers was 0.045–0.120 µg/kg bw/day. The high intake (95 percentile) ranged between 0.182 and 0.396 µg/kg bw/day, well below the 1 µg/kg bw/day tolerable daily intake (TDI) established by EFSA. While the intake calculations resulted in comforting results, maize-based products may indeed be contaminated by fumonisins. Therefore, frequent monitoring of fumonisins’ levels and evaluation of their intakes using the best available data are recommended.

Fumonisins in Serbian Corn: Long-time Assessment under Actual Climate Change Conditions

Maize samples collected in Serbia during a period of seven years were investigated on the presence of fumonisins. Concentration of fumonisins was determined by validated direct competitive Enzyme Linked Immunosorbent Assay method. This method was in accordance with European Union requirements, therefore accredited and performed in the Serbian accredited official laboratory. Summary analysis of all obtained results revealed fumonisins contamination in 82% of the total of 291 maize samples with average contamination being 1.515 mg/kg. An increase in the percentage of contaminated samples (from 51 to 100%), as well as an increase in mean fumonisin concentration in positive samples (from 0.227 to 3.281 mg/kg) and median values in positive samples (from 0.070 to 2.140 mg/kg) was noticed during the observation period. Although in Serbia there is no regular control of fumonisins in corn for animal feeding, long-term results indicate their wide distribution in this grain. Since the data on climate elements show change in temperature and precipitation in relation to multiannual average on the territory of Serbia, further research on the effects of climate change on the development of mold, the appearance of insects and the production of toxins are necessary in order to check the resistance of currently grown hybrids in the territory of Serbia on fungal growth and fumonisins production.

Mycotoxins in Flanders' Fields: Occurrence and Correlations with Fusarium Species in Whole-Plant Harvested Maize.

Mycotoxins are well-known contaminants of several food- and feedstuffs, including silage maize for dairy cattle. Climate change and year-to-year variations in climatic conditions may cause a shift in the fungal populations infecting maize, and therefore alter the mycotoxin load. In this research, 257 maize samples were taken from fields across Flanders, Belgium, over the course of three years (2016–2018) and analyzed for 22 different mycotoxins using a multi-mycotoxin liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. DNA of Fusarium graminearum, F. culmorum and F. verticillioides was quantified using the quantitative polymerase chain reaction (qPCR). Multi-mycotoxin contamination occurred frequently, with 47% of samples containing five or more mycotoxins. Nivalenol (NIV) was the most prevalent mycotoxin, being present in 99% of the samples, followed by deoxynivalenol (DON) in 86% and zearalenone (ZEN) in 50% of the samples. Fumonisins (FUMs) were found in only 2% of the samples in the wet, cold year of 2016, but in 61% in the extremely hot and dry year of 2018. Positive correlations were found between DON and NIV and between F. graminearum and F. culmorum, among others. FUM concentrations were not correlated with any other mycotoxin, nor with any Fusarium sp., except F. verticillioides. These results show that changing weather conditions can influence fungal populations and the corresponding mycotoxin contamination of maize significantly, and that multi-mycotoxin contamination increases the risk of mycotoxicosis in dairy cattle.

The human health benefits from GM crops.

The human health benefits from GM crops.

Fusarium verticillioides FUM1 and FUM19 gene expression in maize kernels during early infection

Fusarium verticillioides is the causal agent of Fusarium ear rot (FER), an economically important disease of maize worldwide. The fungus also produces fumonisins in maize grain, which poses a food safety concern. To better understand the molecular interactions between maize and F. verticillioides during infection, genes expressed in infected and healthy maize kernels have been investigated. The expression of fungal genes in grain during infection has, however, received little attention. This is because fungal RNA forms only a fraction of the total RNA present in maize kernels, making transcriptome sequencing thereof difficult. The aim of this study, thus, was to study the expression of two F. verticillioides fumonisin biosynthetic (FUM) genes in maize kernels by reverse-transcription quantitative PCR (RT-qPCR). The ears of a susceptible maize inbred line were artificially inoculated with F. verticillioides, and maize kernels harvested 0, 7 and 14 days after inoculation (dai). The relative expression of the FUM1 and FUM19 genes was then quantified using RT-qPCR, and correlated to fumonisin levels in the kernels. Both genes were up-regulated in the fungus-inoculated plants 7 dpi, when fumonisin levels and F. verticillioides DNA concentration in the infected kernels increased. After 14 days with increasing fumonisin levels, the relative expression of FUM1 was further increased, but not that of FUM19. There was no significant correlation between in planta FUM gene expression and fumonisin concentration in maize kernels (P > 0.05). The optimization of a RT-qPCR protocol has provided a targeted approach to study fungal genes that play a role in pathogenesis and fumonisin production in planta and can further provide insights into the F. verticillioides-maize pathosystem.

Determination of Fumonisin B1 in maize using molecularly imprinted polymer nanoparticles-based assay

Fumonisin B1 (FB1) is a carcinogenic mycotoxin produced by Fusarium species contaminating maize. At present, fumonisin determination is performed using costly and demanding chromatography techniques or immunoassays. Recently, a molecularly imprinted polymer nanoparticles (nanoMIPs) – based assay (MINA) has been developed for FB1 detection. Herein, we have applied MINA for the determination of FB1 in naturally contaminated maize samples and results were compared with those obtained with ELISA and a reference HPLC method (AOAC No. 2001.04). The nanoMIPs as a recognition element mimicking antibodies used in ELISA were produced by solid phase synthesis and used in MINA for FB1 determination in 53 maize samples. As a result, 18 maize samples were contaminated with FB1 at levels higher than 0.25 mg/kg. Fumonisin concentrations from samples measured by MINA were well correlated with those using ELISA and HPLC. Therefore, MINA could be used as an alternative technique for FB1 determination in maize.

Effects of Disruption of Five FUM Genes on Fumonisin Biosynthesis and Pathogenicity in Fusarium proliferatum.

The mycotoxin fumonisin is known to be harmful to humans and animals, and thus it is desirable to reduce fumonisin content in crop products. We explored the functions of several genes that function in fumonisin biosynthesis (FUM1, FUM6, FUM8, FUM19, and FUM21) in Fusarium proliferatum and found that deletion of FUM1, FUM6, FUM8, or FUM21 results in a severe reduction in fumonisin biosynthesis, while loss of FUM19 does not. In addition, fumonisin-deficient strains display significantly decreased pathogenicity. Co-cultivation of the ΔFUM1, ΔFUM6, ΔFUM8, and ΔFUM19 mutants restores fumonisin synthesis. However, co-cultivation was unable to restore fumonisin synthesis in the ΔFUM21 strain. The relative expression levels of three key FUM genes (FUM1, FUM6, and FUM8) differed significantly in each mutant strain; notably, the expression levels of these three genes were significantly down-regulated in the ΔFUM21 strain. Taken together, our results demonstrate that FUM1, FUM6, FUM8, and FUM21 are essential for fumonisin synthesis, and FUM19 is non-essential. Partial mutants lost the ability to synthesize fumonisin, the co-culture of the mutants was able to restore fumonisin biosynthesis. While the pathogenicity of F. proliferatum is affected by many factors, inhibition of the synthesis of the mycotoxin fumonisin will weaken the pathogenicity of rice spikelet rot disease (RSRD).

Long Term Monitoring (2014⁻2018) of Multi-Mycotoxins in South African Commercial Maize and Wheat with a Locally Developed and Validated LC-MS/MS Method.

Mycotoxins occur worldwide in the major grains, and producers, traders and processors are all challenged to prevent serious health problems for consumers. The challenges originate with pre-harvest fungi infections in the grain fields, increased contamination during improper storage and, finally, the mycotoxin accumulation in commercial food and feed products. Little is known about the multi-mycotoxin occurrence in maize and wheat commercially produced in South Africa. This is the first comprehensive study that reports on the multi-mycotoxin occurrence in South African produced maize and wheat crops after harvest, over four production seasons, in all the production regions of the country. The study was made possible with the development of a fit-for-purpose, cost-effective LC-MS/MS multi-mycotoxin method, validated for 13 “regulated” mycotoxins. A low mycotoxin risk was found in South African produced wheat, with only deoxynivalenol (DON) in 12.5% of the 160 samples at levels well below the 2000 µg/kg South African (SA) regulatory level. It was concluded that aflatoxin B1 (AFB1) is seldom present in South African produced commercial maize. The concentrations, regional variation and seasonal trends of deoxynivalenol and fumonisins, the two most prevalent mycotoxins, and of zearalenone (ZON), are reported for white and yellow maize in all the production provinces, based on the analytical results of 1400 maize samples. A threefold to eightfold increase in deoxynivalenol mean concentrations in white maize was observed in the main production regions in the fourth season, with 8.9% samples above 2000 µg/kg. A strong correlation was found between higher deoxynivalenol concentrations and the presence of 15-acetyl-deoxynivalenol (15-ADON). The mean fumonisin concentrations were well below the 4000 µg/kg South African regulatory value. A possible shift in the incidence and severity of mycotoxigenic Fusarium spp. in the provinces must be investigated. The variations and trends highlight the importance of a continuous monitoring of multi-mycotoxins in South Africa along the grain value chain.

Genome-wide association analysis for fumonisin content in maize kernels

BackgroundPlant breeding has been proposed as one of the most effective and environmentally safe methods to control fungal infection and to reduce fumonisin accumulation. However, conventional breeding can be hampered by the complex genetic architecture of resistance to fumonisin accumulation and marker-assisted selection is proposed as an efficient alternative. In the current study, GWAS has been performed for the first time for detecting high-resolution QTL for resistance to fumonisin accumulation in maize kernels complementing published GWAS results for Fusarium ear rot.ResultsThirty-nine SNPs significantly associated with resistance to fumonisin accumulation in maize kernels were found and clustered into 17 QTL. Novel QTLs for fumonisin content would be at bins 3.02, 5.02, 7.05 and 8.07. Genes with annotated functions probably implicated in resistance to pathogens based on previous studies have been highlighted.ConclusionsBreeding approaches to fix favorable functional variants for genes implicated in maize immune response signaling may be especially useful to reduce kernel contamination with fumonisins without significantly interfering in mycelia development and growth and, consequently, in the beneficial endophytic behavior of Fusarium verticillioides.