Polyphasic approach used for distinguishing Fusarium temperatum from Fusarium subglutinans

Morphological, biological, and phylogenetic approaches were undertaken for the identification of pathogenic species F. temperatum in the Serbian population of F. subglutinans collected in the 1999-2010 period from Zea mays (3 root, 15 stalk, and 6 seed samples), Sorghum bicolor (two seed samples), Hordeum vulgare (one seed sample) and Taraxacum officinale (one seed sample). Based on interspecies mating compatibility analyses and the maximum parsimony analysis of EF-1α sequences, only two strains, originating from S. bicolor seed (MRIZP 0418 and MRIZP 0552), were identified as F. temperatum, while the remaining 26 single-spore strains were identified as F. subglutinans Group 2. In situ detached barley leaf assay and artificially stalk and ear inoculation of two maize hybrids demonstrated that both F. temperatum and F. subglutinans strains were medium and strong pathogens under laboratory and field conditions, respectively. These are the first data on the F. temperatum as seed-borne pathogens of sorghum, as well as pathogenicity of F. temperatum strains on maize

Genetic divergence and chemotype diversity in the fusarium head blight pathogen Fusarium poae

Fusarium head blight is a disease caused by a complex of Fusarium species. F. poae is omnipresent throughout Europe in spite of its low virulence. In this study, we assessed a geographically diverse collection of F. poae isolates for its genetic diversity using AFLP (Amplified Fragment Length Polymorphism). Furthermore, studying the mating type locus and chromosomal insertions, we identified hallmarks of both sexual recombination and clonal spread of successful genotypes in the population. Despite the large genetic variation found, all F. poae isolates possess the nivalenol chemotype based on Tri7 sequence analysis. Nevertheless, Tri gene clusters showed two layers of genetic variability. Firstly, the Tri1 locus was highly variable with mostly synonymous mutations and mutations in introns pointing to a strong purifying selection pressure. Secondly, in a subset of isolates, the main trichothecene gene cluster was invaded by a transposable element between Tri5 and Tri6. To investigate the impact of these variations on the phenotypic chemotype, mycotoxin production was assessed on artificial medium. Complex blends of type A and type B trichothecenes were produced but neither genetic variability in the Tri genes nor variability in the genome or geography accounted for the divergence in trichothecene production. In view of its complex chemotype, it will be of utmost interest to uncover the role of trichothecenes in virulence, spread and survival of F. poae

A European Database of Fusarium graminearum and F. culmorum Trichothecene Genotypes

. Fusarium species, particularly Fusarium graminearum and F culmorum, are the main cause of trichothecene type B contamination in cereals. Data on the distribution of Fusarium trichothecene genotypes in cereals in Europe are scattered in time and space. Furthermore, a common core set of related variables (sampling method, host cultivar, previous crop, etc.) that would allow more effective analysis of factors influencing the spatial and temporal population distribution, is lacking. Consequently, based on the available data, it is difficult to identify factors influencing chemotype distribution and spread at the European level. Here we describe the results of a collaborative integrated work which aims (1) to characterize the trichothecene genotypes of strains from three Fusarium species, collected over the period 2000-2013 and (2) to enhance the standardization of epidemiological data collection. Information on host plant, country of origin, sampling location, year of sampling and previous crop of 1147 F graminearurn, 479 F culmorum, and 3 F cortaderiae strains obtained from 17 European countries was compiled and a map of trichothecene type B genotype distribution was plotted for each species. All information on the strains was collected in a freely accessible and updatable database (www.catalogueeu.luxmcc.lu), which will serve as a starting point for epidemiological analysis of potential spatial and temporal trichothecene genotype shifts in Europe. The analysis of the currently available European dataset showed that in F. grarninearum, the predominant genotype was 15-acetyldeoxynivalenol (15-ADON) (82.9%), followed by 3-acetyldeoxynivalenol (3-ADON) (13.6%), and nivalenol (NIV) (3.5%). In F culmorum, the prevalent genotype was 3-ADON (59.9%), while the NIV genotype accounted for the remaining 40.1%. Both, geographical and temporal patterns of trichothecene genotypes distribution were identified.</p

A European Database of Fusarium graminearum and F-culmorum Trichothecene Genotypes

Fusarium species, particularly Fusarium graminearum and F culmorum, are the main cause of trichothecene type B contamination in cereals. Data on the distribution of Fusarium trichothecene genotypes in cereals in Europe are scattered in time and space. Furthermore, a common core set of related variables (sampling method, host cultivar, previous crop, etc.) that would allow more effective analysis of factors influencing the spatial and temporal population distribution, is lacking. Consequently, based on the available data, it is difficult to identify factors influencing chemotype distribution and spread at the European level. Here we describe the results of a collaborative integrated work which aims (1) to characterize the trichothecene genotypes of strains from three Fusarium species, collected over the period 2000-2013 and (2) to enhance the standardization of epidemiological data collection. Information on host plant, country of origin, sampling location, year of sampling and previous crop of 1147 F graminearurn, 479 F culmorum, and 3 F cortaderiae strains obtained from 17 European countries was compiled and a map of trichothecene type B genotype distribution was plotted for each species. All information on the strains was collected in a freely accessible and updatable database (www.catalogueeu.luxmcc.lu), which will serve as a starting point for epidemiological analysis of potential spatial and temporal trichothecene genotype shifts in Europe. The analysis of the currently available European dataset showed that in F. grarninearum, the predominant genotype was 15-acetyldeoxynivalenol (15-ADON) (82.9%), followed by 3-acetyldeoxynivalenol (3-ADON) (13.6%), and nivalenol (NIV) (3.5%). In F culmorum, the prevalent genotype was 3-ADON (59.9%), while the NIV genotype accounted for the remaining 40.1%. Both, geographical and temporal patterns of trichothecene genotypes distribution were identified

From taxonomy to field monitoring, a polyphasic approach applied to Fusarium temperatum sp. nov.

Numerous Fusarium species are important mycotoxin-producing pathogens affecting maize worldwide. Crop quality is often reduced by ear and stalk rot diseases, and mycotoxin contaminations can pose a serious problem for both human and animal health. As several Fusarium species are integrated into legislation, commercial trade agreements, or quarantine regulations, field monitoring and accurate identification of the Fusarium species involved in diseases have been and remain important tasks, allowing relevant preventive or curative measures. In the present work, we contributed to an example of integrated description, study and management of a new Fusarium species, from its taxonomical status to its potential field impacts. We used a robust polyphasic approach based on amplified fragment length polymorphism, on phylogenetic studies using maximum parsimony and Bayesian inference, on biological characterization using diagnostic sexual crosses, and on morphological recognition to formally describe F. temperatum sp. nov. According to a three-year epidemiological survey, to pathogenicity tests in greenhouse conditions and to in vitro toxin production studies, F. temperatum clearly contributes to the risk of disease development and mycotoxin accumulation in maize fields. Therefore, a rapid, specific and sensitive real-time PCR protocol was developed for detection and quantification of four mycotoxigenic Fusarium species including F. temperatum, in monoplex and multiplex conditions. Such an integrated description study might contribute to taxonomical clarification between other potential distinct species that are included in individual morphospecies or species complexes, resulting in better focused and species-targeted efforts for field monitoring and mycotoxin management.(AGRO 3) -- UCL, 201

Etat de la fusariose sur maïs en Wallonie

En Belgique, plus de huit millions de tonnes de maïs sont annuellement récoltés sur 222.000 ha de terres agricoles, sous forme de maïs-fourrage et de maïs-grain. Cependant, la qualité des plants est souvent affectée par la fusariose. Plusieurs espèces de Fusarium sont en effet responsables de pertes de rendement au champ et leurs productions de mycotoxines peuvent causer de graves problèmes de santé aux animaux

Fusarium temperatum sp. nov. from maize, an emergent species closely related to Fusarium subglutinans.

A large number of Fusarium isolates closely related to F. subglutinans were collected from maize in Belgium. We used a robust polyphasic approach to describe a new biological species, Fusarium temperatum, within the Gibberella fujikuroi species complex. F. temperatum can be distinguished from F. subglutinans and from other Fusarium species within the Gibberella fujikuroi species complex with AFLP fingerprint profile, differences in the translation elongation factor 1-α and β-tubulin DNA sequence and interspecies mating compatibility analyses. Intraspecies mating compatibility suggests that sexual reproduction might be common for field isolates of F. temperatum, and reliable female fertile mating population tester strains were proposed for this heterothallic species

Fusarium temperatum, a new species from maize closely related to Fusarium subglutinans

A novel biological species, Fusarium temperatum J. Scauflaire et F. Munaut was described within the Gibberella fujikuroi species complex (GFSC), on basis of a robust polyphasic approach. The morphology, the mating compatibilities, the genetic diversity and its relationships with species within the GFSC were analyzed

From plants to silage: the mycotoxin problematic

In Belgium, silage constitutes the basic cattle forage during winter and, in part, also during summer. There are different crops used for ensilage such as whole corn plant, CCM (corn cob mix), grass, and sugar beet pulp. Among the various clients of BCCM/MUCL, farmers or industries often ask for help with health problems encountered in livestock fed with fungal and presumably mycotoxin contaminated silage. However, little information is are available that could be used to assess the risks of such contaminations by fungal toxic secondary metabolites, largely because most of the suspected effects are non-specific (reduction of fertility, reduction of productivity, immunosuppressive effects, etc.) and subject to influences other than simply feed quality. However, the presence of molds is a good indication of the likelihood of mycotoxin problems. Several mycotoxin-producing genera such as Penicillium, Aspergillus, and Byssochlamys have often been isolated from silage samples. Those genera are perfectly adapted to silage conditions and can be correlated with the presence of mycotoxins. In addition, fusarial toxins (toxins produced by various species of Fusarium) have been detected in significant quantities in silage samples, although the living conditions for Fusaria are not optimum in such matrices. Therefore, the presence of the mycotoxins could be accounted for by fungal production while the plants were growing. In that context, BCCM/MUCL introduced two research projects in order to analyze both silage and plants at the fungal and the mycotoxigenic levels