engleski

Temporal variation of microbial communities associated with marine macrophyte surfaces

Surfaces of marine macrophytes (seagrasses and macroalgae) are inhabited by diverse microbial communities. To study these microorganisms a combination of methods such as 16S rRNA sequencing, metagenomics and metaproteomics is often applied. In studies focusing on the temporal variation of surface associated communities it is advisable to perform a selective DNA and/or protein isolation prior to the analysis to avoid host material biases, and to apply a high frequency approach. To determine the temporal variation of epiphytic communities on the surfaces of the seagrass Cymodocea nodosa and the invasive macroalga Caulerpa cylindracea we developed a removal protocol, based on direct cellular lysis to ensure an almost complete epiphytic cell detachment. Illumina MiSeq sequencing of the V4 region of the 16S rRNA was performed to characterize epiphytic and ambient water prokaryotic communities. Leaves and thalli were sampled in a meadow of Cymodocea nodosa invaded by the invasive Caulerpa cylindracea and in a monospecific settlement of Caulerpa cylindracea located in the proximity of the meadow at monthly intervals. Generally, bacterial sequences dominated over archaeal. At high taxonomic ranks similar taxa were determined in the ambient water and epiphytic communities, while at lower taxonomic levels major differences were observed. Epiphytic communities were influenced more by the host species than by season. Different taxa were characterized by distinct temporal variation with Cyanobacteria-related taxa showing the highest degree of seasonal changes. In addition, we show that biological material obtained by the developed removal protocol was suitable for identification by mass spectrometry and metagenomic sequencing. Taken together, surface associated microbial communities of the seagrass Cymodocea nodosa and the macroalga Caulerpa cylindracea appear to be host-specific and contain groups that undergo successional changes.

selective isolation ; DNA, proteins ; marine macrophytes ; Cymodocea nodosa ; Caulerpa cylindracea

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