The Hidden Wood-Decaying Fungal Diversity: Rhizochaete from East Asia

Abstract

Wood-decaying fungi play crucial roles as decomposers in forest ecosystems. In this study, two new corticioid fungi, Rhizochaete fissurata and R. grandinosa spp. nov., are proposed based on a combination of morphological features and molecular evidence. Rhizochaete fissurata is characterized by resupinate basidiomata with a cracking hymenial surface, a monomitic hyphal system with simple-septa generative hyphae, presence of subfusiform to conical cystidia encrusted at the apex or coarse on the upper half, and ellipsoid basidiospores. Rhizochaete grandinosa differs in its resupinate basidiomata with a smooth hymenial surface, presence of two types of cystidia, and ellipsoid basidiospores. Sequences of ITS and nLSU rRNA markers of the studied samples were employed, and phylogenetic analyses were performed with maximum likelihood, maximum parsimony, and Bayesian inference methods on two datasets (ITS+nLSU and ITS). Both dataset analyses showed that two new species clustered into the genus Rhizochaete, in which, based on the ITS+nLSU dataset, R. fissurata was sister to R. belizensis, and R. grandinosa grouped with R. radicata; the phylogram inferred from ITS sequences inside Rhizochaete indicated that R. fissurata formed a monophyletic lineage with a lower support; R. grandinosa grouped closely with R. radicata. In addition, an identification key to all Rhizochaete species worldwide is provided.