Comparison of Seiridium Isolates Associated with Cypress Canker Using Sequence Data

Viljoen, C. D., Wingfield, B. D., and Wingfield, M. J. 1993. Comparison of Seiridium isolates associated with cypress canker using sequence data. Experimental Mycology 17, 323-328. Three species of Seiridium have been associated with cypress canker. These include Seiridium cardinale, Seiridium unicorne, and Seiridium cupressi and are distinguished based on conidial appendage morphology. Some authorities believe that S. cupressi is conspecific with S. unicorne as these two species possess appendaged conidia while S. cardinale does not. Others are of the view that only one species of Seiridium with variable morphology is associated with cypress canker. In this study the variable first internal transcribed spacer region of the ribosomal RNA genes, from isolates of Seiridium associated with cypress canker, was sequenced and compared. Results suggest that species of Seiridium associated with cypress canker are closely related. Moreover sequence data support the view that S. cupressi and S. unicorne are synonyms of S. cardinale.