Bacterial community composition of the sea grape Caulerpa lentillifera: a comparison between healthy and diseased states

Abstract

The bacterial communities of the sea grape Caulerpa lentillifera were studied during a disease outbreak in Vietnam. The Rhodobacteraceae and Rhodovulum dominated the composition of healthy C. lentillifera. Clear differences between healthy and diseased cases were observed at order, genus and Operational Taxonomic Unit (OTU) level. Bacterial diversity was lower in healthy C. lentillifera, probably because of antimicrobial compounds from the macroalgae and/or from Clostridium, Cutibacterium or Micrococcus bacteria. The likely beneficial role of Bradyrhizobium, Paracoccus and Brevundimonas strains on nutrient cycling and phytohormone production was discussed. The white coloration of diseased C. lentillifera may not only be associated with pathogens but also with an oxidative response. Aquibacter, Winogradskyella and other OTUs of the family Flavobacteriaceae were hypothesized as detrimental bacteria, this family comprises some well-known seaweed pathogens. Moreover, Thalassobius OTU 2935 and 1635 may represent detrimental Rhodobacteraceae. Phycisphaera together with other Planctomycetes and Woeseia were probably saprophytes of C. lentillifera. This study offers pioneering insights on the co-occurrence of C. lentillifera-attached bacteria, potential detrimental or beneficial microbes, and a baseline for understanding the C. lentillifera holobiont. Further metagenomic and biotechnological approaches are needed to confirm functions of some microbes on this macroalgae to enhance food security in the tropics.

Microbiome and epigenetic variation in wild fish with low genetic diversity

“…Indicative speciesspecific ASVs included different ribotypes of Sulfurovum, which oxidises sulphur and thiosulfate and is found in the gut and gill microbiome of marine invertebrates (like sea cucumber and snails) where it could be providing detoxification and nutritional intake for the host 46 . Indicative ASVs related to location included Phycisphaeraceae, a member of the scarcely studied class Phycisphaerae, common in the marine environment 47,48 and the microbiome of freshwater fish living in anoxic conditions 49 , such as those found in mangrove killifish habitats 50 (Supplementary Data 4).…”

Inferring potential causative microbial factors of intestinal atrophic disease in the sea cucumber Apostichopus japonicus

“…Origin shows the original samples collected from sea cucumber or seawater, red represents sea cucumber, blue represents seawater, Status shows the healthy status of samples, purple represents atrophic samples, and green represents healthy samples. sea grape, it has not been directly implicated as a pathogenic bacterium causing disease outbreaks (Kopprio et al, 2021). Bacteria in the genus Ruegeria are associated with coral diseases such as Montipora white syndrome (MWS), but they can also act as commensal bacteria in healthy corals (Casey et al, 2015).…”

The interaction between microbiome and epigenetic diversity as a source of phenotypic variation for fish with low genetic diversity

“…Indicative species-speci c ASVs included different ribotypes of Sulfurovum, which oxidises sulphur and thiosulfate and is found in the gut and gill microbiome of marine invertebrates (like sea cucumber and snails) where it could be providing detoxi cation and nutritional intake for the host 47 . Indicative ASVs related to the location included Phycisphaeraceae, a member of the scarcely studied class Phycisphaerae, common in the marine environment 48,49 and in the microbiome of freshwater sh and is related to low dissolved oxygen levels 50 , such as those found in mangrove killi sh habitats 51 (Supplementary material Table S3).…”