Survey of the wheat mycobiome associated with leaf blotch and head blight diseases in Sweden

Increasing the durability of crop resistance to plant pathogens has become a major concern in plant pathology. There are 32 diseases of agronomical importance in wheat, which makes disease management in this crop of worldwide importance extremely challenging. Two important groups of wheat pathogens driving the consumption of chemical fungicides in Sweden and worldwide are those causing head blight diseases and leaf blotch diseases. Swedish fields are regularly infested with head blight diseases typically driven by a complex of Fusarium and non-fusarium taxa including F. graminearum, F. culmorum, while leaf blotches are typically caused by Zymoseptoria tritici, Pyrenophora tritici-repentis, and Parastagonospora nodorum. In this work, we present a survey of the larger diversity of taxa associated with head blight and leaf blotch diseases in Sweden, with the primary aim to assess the usefulness of such an approach to develop new understanding and tools for disease diagnostics and management sensu lato. Here, we analyze nearly a thousand isolates collected from wheat fields across eight counties in Sweden and report the identification of pathogenic and non-pathogenic taxa as well as candidate biological control agents associated with head blight and leaf blotch diseases. We argue that such surveys represent an important tool for improving disease diagnostics, disease forecasting, and integrated management in wheat.