Study of the microbiota of Ulva spp. and its surrounding environment through 16S rRNA gene amplicon sequencing, 2021/2022

The surface microbiota of macroalgae belonging to the Ulva genus was sampled over a period of one and a half years, every two months, during low tide at high tide coefficients. The specimens were collected from the Kerleven beach in southern Finistere, and samples of rocky substrates and seawater were also collected to study the microbiota surrounding the macroalga. Bacterial diversity was investigated by targeting the V3-V4 region of the 16S rRNA gene, using the NOCHL primers developed by Thomas et al., (2020) to minimize plastid amplification. This set of primers consisted of the forward primer S-D-Bact-0341-b-S-17 (CCTACGGGNGGCWGCAG), and the reverse primer S-D-Bact-0785-a-A-21 (GACTACHVGGGTATCTAATCC), and amplified a 478 bp fragment. The amplicons were paired-end sequenced (2 x 250 bp) on an Illumina MiSeq platform (Genome Quebec, Canada)