Evolution
The fungus Mycosphaerella graminicola has been a pathogen of wheat since host domestication 10,000–12,000 years ago in the Fertile Crescent. The wheat-infecting lineage emerged from closely related Mycosphaerella pathogens infecting wild grasses. It has coevolved and spread with its host globally. Mycosphaerella graminicola shows a significantly higher degree of host specificity and virulence in a detached leaf assay.
The emergence and "co-domestication" of Mycosphaerella graminicola was associated with an adaptation to wheat and an agricultural environment. Endemic descendants of the progenitor of Mycosphaerella graminicola are still found on wild grasses in the Middle East; however these "wild" pathogens show a broader host range than the "domesticated" wheat pathogen. The closest known relative of Mycosphaerella graminicola is named Mycosphaerella graminicola subspecies 1. Mycosphaerella graminicola subspecies 1 was isolated in Iran from the two grass species Agropyron repens and Dactylis glomerata growing in close proximity to fields planted to bread wheat (Triticum aestivum). Although Mycosphaerella graminicola is a frequent pathogen of wheat in Iran, no evidence of gene flow between Mycosphaerella graminicola subspecies 1 and Mycosphaerella graminicola was detected based on sequence analysis of six nuclear loci.
Read more about this topic: Mycosphaerella Graminicola
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