Dissecting the Biology of the Fungal Wheat Pathogen Zymoseptoria tritici: A Laboratory Workflow

Abstract

The fungus Zymoseptoria tritici is one of the most devastating pathogens of wheat. Aside from its importance as a disease-causing agent, this species has emerged as a powerful model system for evolutionary genetic studies of cropinfecting fungal pathogens. Z. tritici exhibits exceptionally high levels of genetic and phenotypic diversity as well as morphological plasticity, which can make experimental studies and comparability of results obtained in different laboratories, e.g., from infection assays, challenging. Therefore, standardized experimental methods are crucial for research on Z. tritici biology and the interaction of this fungus with its wheat host. Here, we describe a suite of well-tested and optimized protocols ranging from isolation of Z. tritici field specimens to analyses of virulence assays under controlled conditions. Several biological and technical aspects of working with Z. tritici under laboratory conditions are considered and carefully described in each protocol.

Resistance of the Wheat Cultivar ‘Renan’ to Septoria Leaf Blotch Explained by a Combination of Strain Specific and Strain Non-Specific QTL Mapped on an Ultra-Dense Genetic Map

“…This simplifies phenotyping as, in field conditions, other diseases with similar symptoms to STB can infect crops. Septoria nodorum blotch caused by fungal pathogen Parastagonospora nodorum in particular can lead to confusion [ 69 ]. Other external factors such as environmental variations can also greatly impact field conditions, compromising experiments’ success [ 70 ].…”

Differential Regulation and Production of Secondary Metabolites among Isolates of the Fungal Wheat Pathogen Zymoseptoria tritici

“…Further functional characterization of the gene BGF_20:OG_1946 (ABA; 50% similarity) would shed light on whether this metabolite plays a role during host colonization by interfering with induced defense signaling in the pathogen Z. tritici . Genetic tools are available for Z. tritici , allowing the deletion of larger fragments of DNA or individual genes by Agrobacterium -mediated transformation ( 21 ). Deletion of the ABA gene cluster or the core ABA gene will allow a detailed assessment of the relevance of ABA production in successful host colonization of Z. tritici .…”

“…In this study, we used three Z. tritici isolates that were previously described ( 26 ). Previous studies using axenic propagation of Z. tritici have used fungal cells propagated on yeast-malt-sucrose (YMS) medium ( 21 ), and similar growth conditions were used in this study. YMS-agar medium was prepared with 0.4% (wt/vol) yeast extract (Bacto yeast extract; Thermofisher), 0.4% (wt/vol) malt extract, and 0.4% (wt/vol) sucrose supplemented with 2% (wt/vol) Bacto agar.…”

“…In silico predictions of gene clusters have demonstrated how BGCs are enriched in the more rapidly evolving subtelomeric regions of the genome of Z. tritici , which may facilitate genetic diversification of the BGCs ( 20 ). Z. tritici is also characterized by an exceptionally high variability in growth morphology, for example, some isolates being highly melanized and others nonmelanized when grown under laboratory conditions ( 21 ). The extensive genetic and phenotypic variability manifested by this fungus led us to hypothesize a comparably high variation in overall secondary metabolite production.…”

Divergent outcomes of direct conspecific pathogen strain interaction and plant co-infection suggest consequences for disease dynamics

“…Z. tritici is a major fungal pathogen of wheat causing the economically important foliar disease Septoria tritici blotch (STB) (26). Z. tritici exhibits a symptomless phase after coming into contact with wheat leaves lasting 8–11 days post infection (dpi), during which the fungus does not induce visible host defense responses (27, 28). In later stages, the fungus invades the intercellular space of leaves producing lesions and asexual fruiting bodies called pycnidia.…”