Phylogenetic study documents different speciation mechanisms within the Russula globispora lineage in boreal and arctic environments of the Northern Hemisphere

Miroslav Caboň,Donald H Pfister,Pierre-Arthur Moreau,Slavomír Adamčík,Guo-Jie Li,Malka Saba,Miroslav Kolařík,Abdul Nasir Khalid,Hua-An Wen,Soňa Jančovičová

doi:10.1186/s43008-019-0003-9

Abstract

The Russula globispora lineage is a morphologically and phylogenetically well-defined group of ectomycorrhizal fungi occurring in various climatic areas. In this study we performed a multi-locus phylogenetic study based on collections from boreal, alpine and arctic habitats of Europe and Western North America, subalpine collections from the southeast Himalayas and collections from subtropical coniferous forests of Pakistan. European and North American collections are nearly identical and probably represent a single species named R. dryadicola distributed from the Alps to the Rocky Mountains. Collections from the southeast Himalayas belong to two distinct species: R. abbottabadensis sp. nov. from subtropical monodominant forests of Pinus roxburghii and R. tengii sp. nov. from subalpine mixed forests of Abies and Betula. The results suggest that speciation in this group is driven by a climate disjunction and adaptation rather than a host switch and geographical distance.

Highlights

Russula is a cosmopolitan genus of basidiomycetes comprising hundreds of species with a mainly agaric habit of the basidiomes (Looney et al 2016)
They altogether correspond to 42 collections in the tree (Fig. 1), and 38 of them are placed in the R. globispora clade with full support
Our collections from Pinus roxburghii mono-dominant forests of the southwest Himalayan Mountains (Pakistan) are grouped in a fully supported clade and below we describe them as a new species bearing the name R. abbottabadensis

Summary

Introduction

Russula is a cosmopolitan genus of basidiomycetes comprising hundreds of species with a mainly agaric habit of the basidiomes (Looney et al 2016). Members of the genus are important ectomycorrhizal (ECM) partners in forest ecosystems and are used as commercially traded edible fungi (Looney et al 2018). A study of global datasets of Russula shows only small overlaps in species diversity between geographically distant areas in the Northern Hemisphere (Looney et al 2016). Current studies suggest that Russula species reported from multiple continents are mainly boreal-arctic taxa. Bazzicalupo et al (2017) found that 17 of 72 Russula species from the Northwest of the USA (mostly from boreal-arctic areas) matched a sequence of European barcoded taxa.

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Conclusion