TY - JOUR T1 - Hologenome theory supported by cooccurrence networks of species-specific bacterial communities in siphonous algae (Caulerpa) A1 - Aires,Tania A1 - Moalic,Yann A1 - Serrao,Ester A1 - Arnaud-Haond,Sophie AD - Univ Algarve, Ctr Marine Sci, CCMAR, P-8005139 Faro, Portugal. AD - IFREMER, Technopole Brest Iroise, F-29280 Plouzane, France. AD - Univ Bretagne Occidentale, CNRS, IUEM, Lab Microbiol Environm Extremes,UMR 6197, Plouzane, France. AD - UMR MARBEC Marine Biodivers Exploitat & Conservat, F-34203 Sete, France. UR - https://doi.org/10.1093/femsec/fiv067 DO - 10.1093/femsec/fiv067 KW - endophytic bacteria KW - bacterial community KW - cooccurrence network KW - modularity KW - coevolution N2 - The siphonous algae of the Caulerpa genus harbor internal microbial communities hypothesized to play important roles in development, defense and metabolic activities of the host. Here, we characterize the endophytic bacterial community of four Caulerpa taxa in the Mediterranean Sea, through 16S rRNA amplicon sequencing. Results reveal a striking alpha diversity of the bacterial communities, similar to levels found in sponges and coral holobionts. These comprise (1) a very small core community shared across all hosts (< 1% of the total community), (2) a variable portion (ca. 25%) shared by some Caulerpa taxa but not by all, which might represent environmentally acquired bacteria and (3) a large (> 70%) species-specific fraction of the community, forming very specific clusters revealed by modularity in networks of cooccurrence, even in areas where distinct Caulerpa taxa occurred in sympatry. Indirect inferences based on sequence homology suggest that these communities may play an important role in the metabolism of their host, in particular on their ability to grow on anoxic sediment. These findings support the hologenome theory and the need for a holistic framework in ecological and evolutionary studies of these holobionts that frequently become invasive. Y1 - 2015/07 PB - Oxford Univ Press JF - Fems Microbiology Ecology SN - 0168-6496 VL - 91 IS - 7 SP - 1 EP - 14 ID - 38800 ER -