Molecular Data Reveals Rich Diversity of the Sequestrate Genus Melanogaster (Boletales, Paxillaceae) with Emphasis on the Species from China

Abstract

Malanogaster are ectomycorrhizal fungi characterized by hypogeous fruitbodies. Many ITS rDNA sequences of Malanogaster are recovered from molecular surveys of fungal communities, and remain insufficiently identified making it difficult to determine whether these sequences represent conspecific or novel taxa. In this study, the ITS sequences of Malanogaster were collected comprehensively and analyzed within ITS-based phylogenetic framework. Twenty-one distinct phylogenetic species can be distinguished based on the ITS phylogeny and a threshold of 98% ITS sequence identity, and most species of Melanogaster showed more than 98.1% intraspecific ITS identity and less than 97.9% interspecific identity. Ten species were recognized from China, but combined morphology, nine of which were described and illustrated in this manuscript, including 4 new species (M. minobovatus nov. sp., M. panzhihuaensis nov. sp., M. quercus nov. sp. and M. tomentellus nov. sp.), 1 new combination (M. obvatus comb. & stat. nov.), and 4 known species (M. broomeanus, M. shanxiensis, M. spinisporus, M. subglobisporus). Significantly amendments were added to M. spinisporus and M. subglobisporus. M. fusisporus was added a new mature specimen from type location, and the description and exquisite illustrations were provided also. The diagnostic characteristics of the genus Melanogaster and a key to the Chinese species of the genus Melanogaster were provided. A 28 Sphylogeny was also conducted to confirm the phylogenetic locations of Chinese Melanogaster species and “Alpova trappei”, consistented with ITS analysis.