Delineation of Cylindrocladium species with 1-3-septate conidia and clavate vesicles based on morphology and rDNA RFLPs
Unidentified isolates of Cylindrocladium with 1-3-septate conidia and clavate vesicles were compared with C. theae, C. colhounii var. colhounii, C. colhounii var. macroconidiale, C. gracile, C. pteridis and Calonectria gracilis. Ribosomal DNA (rDNA) of these isolates were digested with the restriction enzymes EcoR I, Hind III and Xho I, and Southern analysis performed with the 6·3-kb rDNA repeat unit of Neurospora crassa as DNA probe. Based on differences in general morphology, supported by their rDNA restriction fragment length polymorphisms, isolates of all species and varieties could be distinguished. Furthermore, the Cylindrocladium anamorph of Calonectria gracilis was shown to be distinct from Cylindrocladium pteridis and C. gracile. The name Cylindrocladium pseudogracile sp. nov. is, therefore, proposed for the undescribed anamorph of Calonectria gracilis.