ARS | Publication request: SEPTORIA PASSERINII FROM BARLEY IS CLOSELY RELATED TO THE WHEAT PATHOGEN MYCOSPHAERELLA GRAMINICOLA

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: March 30, 2000
Publication Date: N/A

Technical Abstract: Septoria passerinii, the cause of barley speckled leaf blotch, has no known teleomorph. It probably is related to other fungi with a Septoria anamorph, such as the septoria tritici blotch pathogen of wheat, Mycosphaerella graminicola. To test whether S. passerinii is related to M. graminicola, their ITS sequences were compared. Six isolates of S. passerinii from Hordeum vulgare shared the same 569 bp sequence. One morphologically identical isolate from H. jubatum had a 569 bp sequence that differed from the H. vulgare-isolate sequence by 7 bp. The ITS sequence of M. graminicola differed from those of both forms of S. passerinii by 10 bp. All three ITS sequences could be distinguished by restriction enzyme digestion of PCR products. ITS sequences were obtained from additional species of Mycosphaerella and/or were downloaded from GenBank. A neighbor-joining tree revealed that both forms of S. passerinii were closely related to M. graminicola and clustered within a monophyletic group of Mycosphaerella species. Thus, if S. passerinii has a teleomorph, it probably is a Mycosphaerella. The isolate from H. jubatum may represent a new, undescribed sibling species of Septoria.