Archaeorhizomycetes: Patterns of Distribution and Abundance in Soil

Abstract

Soil fungal ecology has developed tremendously with the introduction of environmental sequencing. The soil under our feet harbors great fungal diversity including species and even lineages of unknown identity. Beyond identification we can use environmental sequences to trace distribution patterns of species and lineages to better understand their life strategies and ecological roles. Environmental sequences provide the largest available source of information on the ecology of Archaeorhizomycetes, a class of globally distributed ubiquitous soil fungi for which there are no known fruiting structures and only two of over 250 estimated species have been cultured.

The class was initially known as the Soil Clone Group 1 (SCG1) (Porter et al., Mol Phylogenet Evol 46:635–644, 2008) based on environmental sequences from four diverse ecosystems and 12 published studies. Porter et al. highlighted two important features of the class Archaeorhizomycetes: its broad distribution across diverse ecosystems as well as its high species diversity within sites. When the class of Archaeorhizomycetes was formally described by Rosling et al. (Science 333: 876–879, 2011), thousands of ITS sequences were available in public databases. Based on metadata associated with these sequences, ecosystem specificity and geographic distribution patterns emerged among several putative species, i.e., OTUs, within the class. In this chapter, we expand upon earlier analyses of distribution by adding complementary datasets including environmental LSU and SSU sequences. Habitat specificity and geographic distribution are further analyzed using public and previously unpublished sequences from ten field studies in Alaska.