title: Alnus glutinosa and soil microbial community response to HCH contamination
design: DNA extraction of soil and rhizosphere samples was undertaken in duplicate using the DNeasy power Soil KIT (Qiagen, Netherlands). DNA yield and quality were then assessed using a Qubit fluorometer (Thermo Fisher Scientific, USA) and agarose gel electrophoresis. The V4 region of the bacterial 16S rDNA gene was amplified using the primers 530F (5TGCCAGCMGCNGCGG3) and 802R (5TACNVGGGTATCTAATCC3), while for fungal abundance, the ITS2 region was amplified using the primers ITS3-F (5 GCATCGATGAAGAACGCAGC3) and ITS4-R (5 TCCTCCGCTTATTGATATGC3). The amplicons were cleaned using the Agencourt Ampure XP system (Beckman Coulter, USA) and the Ion Torrent platform (Thermo Fisher Scientific, USA) was used for sequencing analysis. Barcoded sequencing adapters were ligated to the PCR products using the Ion Xpress Plus gDNA fragment library kit with Ion Xpress barcode adapters (Thermo Fisher Scientific, USA) and the samples analysed using the Ion PGM Hi-Q Sequencing Kit using an Ion 314 Chip (Thermo Fisher Scientific, USA).