Comparison of smut fungi colonization styles and signals required for spatiotemporal orientation of smuts in planta.
How do smut fungi use plant signals to spatiotemporally orientate on and in planta?
Karina van der Linde, Vera Göhre (2021). .
More than 1000 teliospore-forming fungi, which cause plant smut diseases, have been identified so far. The term smut stems from the German term “schmutzig” (English: dirty) and regards the appearance of infected plant material, which is caused by a massive amount of black, melanized teliospores. The vast majority of smut fungi infect angiosperms, and while most prefer annuals, some infect perennial plants [1]. Commonly, smuts are biotrophic pathogens exhibiting a narrow host range. Besides conventional phylogenetic classification, the smuts can be separated into three groups: (1) smut fungi that infect locally and form teliospores at the original penetration site; (2) smut fungi that infect systemically and colonize several tissues of their host, with teliospore production distant from the infection site; (3) smut fungi that can infect both locally and systemically (Figure 1). Furthermore, the life cycle of the host plant, e.g., annual vs. perennial, and the infected plant tissues, e.g., aerial vs. below-ground, are valuable points of comparison, since they differ in plant signals providing cues for the fungus (Figure 1). In this review, we compare the different infection strategies used by smut fungi and summarize the underlying signals that enable spatiotemporal orientation of the fungus on and in the plant.
