Serendipita officinale sp. nov. (Serendipitaceae): a new species of orchid mycorrhizal fungus

Serendipita is a prominent fungal genus associated with orchids. In this study, a new species of orchid mycorrhizal fungus, Serendipita officinale, is described and thoroughly studied using morphological and molecular approaches. The fungus was isolated from naturally occurring protocorms of Dendrobium officinale in Chongqing Province, China. S. officinale has been observed to actively promote the germination of seeds and facilitate the seedling development of D. officinale, forming typical mycorrhizal pelotons within protocorm cells. This species is characterized by its characteristics on PDA medium, including the presence of abundant villiform and felty aerial mycelium, uninucleate hyphal cells, and the highest growth rate in terms of colony diameter (78 mm diam. in 2 weeks). Furthermore, analyses of ITS rDNA and LSU sequences also provide additional support for the novelty of this new plant symbiont.