Natural habitats are reservoirs of Fusarium lineages highly pathogenic on Triticum aestivum

Natural habitats serve as reservoirs for Fusarium lineages that pose a significant threat to Triticum aestivum, commonly known as wheat. To explore this further, a study was conducted to isolate Fusarium strains from natural populations of Brassica rapa, a non-agricultural plant species. The researchers discovered that these Fusarium lineages exhibited high diversity and a population structure that correlated with their isolation locations.

Through inoculation assays, the team identified specific Fusarium strains from non-agricultural habitats that demonstrated high aggressiveness towards wheat. Furthermore, they observed that the development of disease in wheat varied depending on the variety used. To gain a deeper understanding, the researchers monitored the fungus's colonization process in both wheat and Brassica plants using microscopy.

The study revealed that Fusarium predominantly colonized the root surfaces of Brassica plants; however, it spread internally within wheat roots, leading to vascular colonization in the shoots of the wheat plant. Crucially, the most aggressive Fusarium strains were sourced from Brittany, a region in France where wheat is extensively cultivated.

This finding highlights the importance of monitoring and understanding Fusarium spill overs from non-agricultural habitats to anticipate and control potential epidemics in wheat, especially in the context of reduced pesticide use as advocated by the European Green Deal.