First occurrence of Pyrenophora semeniperdaa new pathogen on barley in Iran

In a survey of barley leaf spot diseases across East Azerbaijan province in Iran, barley plants with brown leaf spot, were collected from barley fields in the Spiran region, the central district of Tabriz County, East Azerbaijan Province, Iran. The disease incidence was 30 percent in sampled areas. Fungal colonies with similar growth pattern were isolated from symptomatic leaves. The isolates were characterized based on a combination of morphological data and sequence data of ITS-rDNA region as P. semeniperda. Pathogenicity assay was fulfilled using the seed infection method under greenhouse conditions. Correspondingly, P. semeniperdastromata were developed on 90% of intact and 95% of scarifies barley seeds and they failed to germinate. Koch’s postulates were fulfilled by re-isolation of the causal agent from inoculated seeds. To the best of our knowledge, P. semeniperdarepresents a new pathogen on barley in Iran. However, geographical distribution, host range and economic impact of this pathogen on major barley producing areas in Iran remain to be studied.