, the cause of spot form and net form of net blotch on barley, respectively.
DNA sequences from three short-read genome assemblies.
► Randomly selected intergenic regions are not under neutral selection.
► Speciation predates the emergence of agriculture.
► No evidence of recent interbreeding between the isolates net blotch forms studied. These species are necrotrophs, causing cell death and feeding off the nutrients released, and have become recognised diseases only over the last century.
The two barley forms closely resemble each other morphologically and are distinguished by their disease symptoms. NFNB is typified by elongated lesions, where necrosis develops along leaf veins with occasional transverse striations.
SFNB displays more ovoid lesions, often surrounded by a chlorotic zone.
The relationship of the two forms of to each other has remained unclear despite several DNA-based studies.
These have suggested that PTT and PTM are closely related but autonomous and divergent genetic groups ( Bakonyi and Justesen, 2007, Bogacki et al., 2010, Lehmensiek et al., 2010, Rau et al., 2007 and Rau et al., 2003).
However, PTT and PTM can be artificially hybridised to create progeny that are morphologically intermediate and are genetically stable ().
Two studies have also suggested infrequent hybridization may occur naturally ( Campbell et al., 2002 and Leišova et al., 2005).
The uncertainty in these relationships has been due to the small amount of genomic DNA sequence information available and limitations in the marker types deployed.