Conidium development in the Hyalorhinocladiella anamorph of Ophiostoma ips

Abstract

The anamorph of Ophiostoma ips has been suggested to have both sympodial and phialidic conidium development. The phialidic form has consequently been referred to as Acremonium-like and the sympodial form as a species of Hyalorhinocladiella. The aim of this study was to determine the mode of conidium development and consequently the identity of the anamorph of Ophiostoma ips. Light microscopy clearly indicated that sympodial proliferation occurred during conidiogenesis. However, using scanning electron microscopy, conidiogenous cells were found to be annellidic. This was confirmed using transmission electron microscopy where distinct annellations could be distinguished on conidiogenous cells. We conclude that conidium development in the anamorph of Ophiostoma ips is annellidic and that an illusion of sympodial conidium development results from delayed secession of conidia. Hyalorhinocladiella could therefore be an acceptable genus for this fungus, although its circumscription would require modification.

Key Words:

• conidiogenesis
• Hyalorhinocladiella
• Ophiostoma