Stagonospora blotch

Stagonospora nodorum SN15 is a filamentous ascomycete that is a major pathogen of wheat and related cereals. It is also known as Septoria nodorum and the disease is variously called glume blotch and Septoria (or Stagonospora) nodorum blotch (not to be confused with Septoria leaf blotch which is caused by Mycosphaerella graminicola). The sexual stage is important in the field and the teleomorph is called Phaeosphaeria nodorum.

Stagonospora is a member of the Dothideomycetes, a class of fungi that includes many important plant pathogens such as Leptosphaeria, Ascochyta, Pyrenophora, Cochliobolus, Alternaria and Mycosphaerella. It is the first Dothideomycete genome sequence to be publicly released.

The lifecycle of Stagonospora comprises both sexual and asexual phases. The asexual spores are released from pycnidia and rain-splashed to initiate new infection foci. The pycnidiospores germinate on the surface of the leaf and penetrate through stomata and directly through the epidermal cell walls. Cell wall penetrations are often associated with simple swollen hyphopodia. Once inside, hyphae grow through the leaf blade. After a few days and when the leaf cells have largely collapsed, pycnidia are formed to complete the life cycle.