Axenic Synthesis of Ericoid Mycorrhiza in Rhododendron formosanum with Phialocephala Species

Formosan rhododendron (Rhododendron formosanum Hemsl.) is an endemic species of Erica-les in Taiwan. The Rf28 fungal strain was isolated from the roots of Formosan rhododendron and identified as an endophytic species of Phialocephala based on its morphological characteristics. This identification was further supported by a DNA sequence analysis. This species is a new addition to the fungal flora of Taiwan. In ericoid-mycorrhizal synthesis, Rf28-inoculated Formosan rhododendron seedlings exhibited vigorous growth, and an examination of the root ultrastructure revealed the occurrence of hyphal complexes and hyphal coils in cortical cells. These results demonstrated that Formosan rhododendron can form ericoid mycorrhiza in vitro with Phialocephala spp.