Populus nigra biomass after natural biodegradation
The genetic material was firstly sheared into smaller fragments by nebulization. Then the overhangs resulting from fragmentation were converted into blunt ends by using T4 DNA polymerase, Klenow Fragment and T4 Polynucleotide Kinase. An ŇAÓ base was added to the 3' phosphorylated blunt ends of the DNA fragments and the adapters were ligated. Too short fragments were removed with Agencourt AMPure XP Beads (Beckman Coulter Inc, Brea, CA, USA). The libraries were then subjected to 151 paired-end sequencing on Illumina HiSeq2000 platform by using TruSeq SBS Kit v3-HS (Illumina, San Diego, CA, USA) following standard pipelines. The generated raw data were trimmed: leading or trailing low quality  (below quality 3) or 3 N bases were cutted off and reads contaminated by adapter (15 bases overlapped by reads and adapter) or with low quality (20) bases (40% as default, parameter setting at 36 bp) were removed. The obtained Clean Data were used to perform the metagenome sequences.