Additions to the knowledge of Ganoderma in Thailand: Ganoderma casuarinicola, a new record; and Ganoderma thailandicum sp. nov.

Thatsanee Luangharn,Samantha C Karunarathna,Jianchu Xu,Peter E Mortimer,Kevin D Hyde

doi:10.3897/mycokeys.59.36823

Abstract

Ganoderma is a cosmopolitan genus of mushrooms, which can cause root and butt rot diseases on many tree species. Members of this genus are particularly diverse in tropical regions. Some Ganoderma spp. are medicinally active and therefore are used to treat human diseases or as a dietary supplement. In this study, three Ganoderma strains were collected in tropical southern Thailand. Phylogenetic analyses of combined ITS, LSU, TEF1α and RPB2 sequence data indicated that the three strains grouped in a distinct lineage within laccate Ganoderma. One strain was collected from Surat Thani Province clustered in the G. casuarinicola clade with high statistical support (MLBS = 100% / MPBS = 98% / PP = 0.96), while the other two strains of Ganoderma, collected from Nakhon Si Thammarat Province, formed a distinct well-supported clade (MLBS = 100% / MPBS = 100% / PP = 1.00) and are described here as a new species. Ganoderma casuarinicola is reported here as a new record to Thailand. Morphological differences of the two taxa and their closely related taxa are discussed. Colour photographs of macro and micro morphological characteristics and a phylogenetic tree to show the placement of the new record and new species are provided.

Highlights

Ganoderma, a genus of the Ganodermataceae, was established by Karsten (1881) with G. lucidum (Curtis) P
The phylogenetic analyses included 56 taxa and the tree was inferred from the combined internal transcribed spacer gene region (ITS), large subunit rDNA gene region (LSU), TEF1α and RPB2 sequences, which comprise 3,360 characters with gaps; 623 characters for ITS, 930 characters for LSU, Figure 1
We describe a new species of Ganoderma growing on Pinus sp. in tropical southern Thailand, in a well-researched genus

Summary

Introduction

A genus of the Ganodermataceae, was established by Karsten (1881) with G. lucidum (Curtis) P. Justo et al (2017) treated Ganodermataceae as a synonym of Polyporaceae, while Cui et al (2019) state that Ganoderma was not included in Polyporaceae because their double-walled basidiospores are quite different from Polyporaceae. Relevant characteristics for Ganoderma species delimitation are unique to laccate and non-laccate basidiocarps: truncated double walled basidiospores, an apical germinal pore, a thin and colourless external wall (exosporium) and a dark brown internal wall (endosporium) (Moncalvo and Ryvarden 1997; Zhao 1989; Núñez and Ryvarden 2000; Ryvarden 2004). Ganoderma is a cosmopolitan genus and some of the species are pathogenic, causing white rot diseases on rotting stumps, roots and living trunks (Moncalvo and Ryvarden 1997; Pilotti et al 2004). Ganoderma can be a confusing genus to study due to the highly variable morphological features of the species in this group, including intra-species variations (Ryvarden 2000; Papp et al 2017; Hapuarachchi et al 2018a, c; Hapuarachchi et al 2019a, b)

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Conclusion