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

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 these fungal pathogens have been and remain important tasks, allowing relevant preventive or curative measures. In the present work, we proposed an 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, on biological characterization and on morphological recognition to formally describe F. temperatum sp. nov. According to a three-year epidemiological survey, pathogenicity tests in greenhouse conditions and 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. 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.