Novel fungal taxa in an Alaskan boreal forest: phylogenetic affinities, ecologies, and ribosomal RNA secondary structures

Abstract

Phylogenetic analyses suggest that a novel DNA sequence (NS1) found in a boreal forest soil-clone library belongs to the fungal kingdom but does not fall unambiguously within any known class. In order to determine if NS1 codes for an authentic ribosomal RNA (rRNA) gene-copy, I modeled ribosomal RNA secondary structure for four gene regions. Such analyses have never been used on environmental ribosomal sequences before. It appears that NS1 does code for an authentic gene-copy and is not a biological or lab artifact. I also elucidated the habitat preferences, horizon preferences, and fine-scale spatial structure of NS1 using molecular methods. I determined that NS1 was associated with spruce and was found in both the organic and mineral soil horizons. It appears to have a clumped distribution on the scale of a few meters and its spatial distribution shows little inter-annual variability. Together these findings suggest that NS1 does represent an authentic gene-copy and also shed light on the ecology of this putative taxon. I hope future efforts will expand our understanding of both its identity and function.