title: Metagenome of arid mangrove forest soil: SaudiArabia exposed fringe subsurface
design: DNA for bacterial community analysis was extracted from approximately 0.8 g of soil, using the DNeasy PowerSoil Kit (Qiagen, Hilden, Germany). Using the specific primers 341F and 805R (Takahashi et al., 2014) with overhang illumina adapters (Illumina Inc., San Diego, CA, USA), the V3-V4 hypervariable regions of the 16S rRNA gene were amplified by polymerase chain reaction (PCR), at a final reaction volume of 25 L per sample [57]. The amplified samples were cleaned to remove primer-dimers and non-targeted DNA molecules using the SequalPrep Normalization Plate (96) Kit (Invitrogen, Carlsbad, CA, USA). Library preparation was carried out using the Nextera XT Index kit (Illumina Inc., San Diego, CA, USA) in combination with the Qiagen Multiplex PCR Master Mix (Qiagen, Hilden, Germany) that uses the HotStarTaq DNA Polymerase. The cycler was set to 95 C as initial temperature for 15 minutes, followed by 8 cycles of 95 C for 30 seconds, 55 C for 90 seconds, and 72 C for 30 seconds, and a final extension with 95 C for 5 minutes (as specified by the manufacturer), before a second clean-up and normalisation step was performed (SequalPrep Normalization Plate (96) Kit, Invitrogen, Carlsbad, CA, USA). The libraries were then concentrated by vacuum centrifugation to approximately 12-15 nM, their concentration was measured by qPCR, and the amplicon length was validated with a Bioanalyzer at the KAUST Bioscience Core Lab. The samples were then sequenced on the Illumina MiSeq platform - v3 chemistry - (Illumina Inc., San Diego, CA, USA) with paired-end sequencing over 301 cycles.