Characterization of Microbiomes Associated With the Early Life Stages of Sea Cucumber Apostichopus japonicus Selenka

Abstract

There is a lot of evidence indicating pioneer microbes in early life having various effects on later host biology. Because of the influential phylogenetic position of sea cucumber, which is a deep branching clade in Deuterostomia, the attention on the microbiome in sea cucumber has been increasing. Although microbes in sea cucumber have been reported in several studies, there is a lack of knowledge regarding the pioneer microbiota in the early life stages of sea cucumber. In this study, microbiota changes during the larval development of sea cucumber were assessed using a laboratory rearing system. Microbial community structure was likely to be related to the developmental stage and significant alterations were detected in the late auricularia stage. The relative abundances of Oceanospirillales, Alteromonadales, and Rhodobacterales significantly varied after gut formation. A total of 257 strains were isolated from larval developmental stages of sea cucumber and affiliated to 124 ASVs in the metagenomic analysis. This data demonstrates for the first-time dynamic changes of sea cucumber microbiota in the developmental stages in early life.

Unveiling the early life core microbiome of the sea cucumber Apostichopus japonicus and the unexpected abundance of the growth-promoting Sulfitobacter

“…Given that the results revealed the presence of universal core microbiome associated with larval developmental stage, it was of interest to investigate whether there were specific bacteria playing a vital role in the host biology during the early life stage. To enhance our understanding, we used bacterial isolates with sequences matched to key ASVs isolated from the 2019 rearing batch for testing host sea cucumber growth promotion [ 26 ] (Fig. 7 a and Additional file 2 : Fig.…”

“…Bacterial strain BL28 was isolated from sea cucumber larvae at the blastula stage and subsequently identified as S. pontiacus [ 26 ]. This strain was cultured on Marine Agar media (DifcoTM Marine Broth, Becton Dickinson, Franklin Lake, USA) at 20 °C.…”

“…In addition, studies on the re-assembly of the gut microbiome after evisceration emphasize host-associated microbiome plays an important role in gut regeneration and functional recovery [ 24 , 25 ]. Previous study on the establishment of early life microbiome during larval development in sea cucumber revealed dynamic changes of microbiota through seven developmental stages: fertilized egg (FE) and blastula (BL), gastrula (GL), early auricularia (EA), late auricularia (LA), pentactula (PT) and juvenile (JN), which is probably related to larval ontogenesis [ 26 ]. However, due to the limitation of sample size in laboratory settings and microbial functional analysis, the early life core microbiome and their related functions in host biology are still poorly understood.…”

Genome taxonomy of the genus Neptuniibacter and proposal of Neptuniibacter victor sp. nov. isolated from sea cucumber larvae

“…The strain PT1 T was isolated from the pentactula larvae of A . japonicus reared in a laboratory aquarium in July 2019 [ 4 ]. In brief, larvae were collected using 40 μm nylon mesh (FALCON Cell Strainer, Durham, USA), washed once with sterilized seawater, and then manually homogenized in 1 mL filter-sterilized natural seawater for 60 seconds.…”

“…In brief, larvae were collected using 40 μm nylon mesh (FALCON Cell Strainer, Durham, USA), washed once with sterilized seawater, and then manually homogenized in 1 mL filter-sterilized natural seawater for 60 seconds. Ten-fold serial dilutions of the homogenate were cultured on 1/5 strength ZoBell 2216E agar plates [ 4 ]. Bacterial colonies were purified using the same agar plates.…”