DNA-seq of soil samples
Metagenomic DNA from the soil samples was isolated using FastDNA SPIN Kit for soil, DNA was purified using Genomic DNA Clean and ConcentratorTM (ZYMO Research, USA) according to the manufacturers instructions. DNA concentration and purity were determined spectrophotometrically using NanoDrop ND-1000 (NanoDrop Technologies, USA). Amplicons were prepared using two sequential polymerase chain reactions (PCRs) with specific primers. For 16S rRNA gene amplicons, 515 forward (5-GTGYCAGCMGCNGCGG-3) and 926 reverse (5-CCGYCAATTYMTTTRAGTTT-3) primers were used targeting the hypervariable regions V4-V5. For ITS region amplicons,  5.8S_Fun forward (5 AACTTTYRRCAAYGGATCWCT 3) and ITS4_Fun reverse (5 AGCCTCCGCTTATTGATATGCTTAART 3) primers were used. For the second PCR, the primers were modified with adaptor tags and internal barcodes. Resultant amplicons of 16S rRNA genes and ITS regions were purified using SPRIselect magnetic beads (Beckman Coulter, USA) and sent to the Core Facility for Nucleic Acid at the University of Alaska Fairbanks (AK, USA), where the sequencing analysis was performed using Illumina Miseq platform.