Description
This fungus causes septoria tritici blotch of wheat, a disease characterized by necrotic blotches on the foliage. These blotches contain asexual (pycnidia) and sexual (pseudothecia) fructifications.
Asexual state (anamorph, asexual stage was previously named as Septoria tritici): Pycnidiospores are hyaline and threadlike and measure 1.7-3.4 x 39-86 μm, with 3 to 7 indistinct septations. Germiniation of pycnidiospores can be lateral or terminal. Cirrhi are milky white to buff. Sometimes in culture nonseptate, hyaline microspores, measuring 1-1.3 × 5-9 μm, occur outside pycnidia by yeastlike budding.
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Light stimulates yeast-like growth of Mycosphaerella graminicola. Close-up of yeast-like growth of Mycosphaerella graminicola in vitro on V8 agar.
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In vitro production of asexual fructifications (pycnidia; arrow) of Mycosphaerella graminicola on wheat leaf extract agar.
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Penetration of a wheat leaf stoma (arrow) by a pycnidiospore germ tube of Mycosphaerella graminicola.
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Colonization of the mesophyll tissue by an intercellular hypha (arrows) of Mycosphaerella graminicola during the symptomless biotrophic phase of pathogenesis.
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Initiation (arrow head) of a pycnidium of Mycosphaerella graminicola in the substomatal cavity of a wheat leaf.
Sexual state (teleomorph): Perithecia are subepidermal, globose, dark brown, and 68-114 μm in diameter. Asci measure 11-14 × 30-40 μm. Ascospores are hyaline, elliptical, and 2.5-4 × 9-16 μm, with two cells of unequal length.
Read more about this topic: Mycosphaerella Graminicola
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