Lloyd MM and Pespeni MH (2018), Microbiome shifts with onset and progression of...

ECB-ART-46737

Sci Rep 2018 Nov 07;81:16476. doi: 10.1038/s41598-018-34697-w.

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Microbiome shifts with onset and progression of Sea Star Wasting Disease revealed through time course sampling.

Lloyd MM , Pespeni MH .

Abstract
The recent outbreak of Sea Star Wasting Disease (SSWD) is one of the largest marine epizootics in history, but the host-associated microbial community changes specific to disease progression have not been characterized. Here, we sampled the microbiomes of ochre sea stars, Pisaster ochraceus, through time as animals stayed healthy or became sick and died with SSWD. We found community-wide differences in the microbiomes of sick and healthy sea stars, changes in microbial community composition through disease progression, and a decrease in species richness of the microbiome in late stages of SSWD. Known beneficial taxa (Pseudoalteromonas spp.) decreased in abundance at symptom onset and through disease progression, while known pathogenic (Tenacibaculum spp.) and putatively opportunistic bacteria (Polaribacter spp. and Phaeobacter spp.) increased in abundance in early and late disease stages. Functional profiling revealed microbes more abundant in healthy animals performed functions that inhibit growth of other microbes, including pathogen detection, biosynthesis of secondary metabolites, and degradation of xenobiotics. Changes in microbial composition with disease onset and progression suggest that a microbial imbalance of the host could lead to SSWD or be a consequence of infection by another pathogen. This work highlights the importance of the microbiome in SSWD and also suggests that a healthy microbiome may help confer resistance to SSWD.

PubMed ID: 30405146
PMC ID: PMC6220307
Article link: Sci Rep

Genes referenced: LOC100887844 LOC105441782

Article Images: [+] show captions

	Figure 1. Sea Star Wasting Disease progression through the two-week experiment. (A) Photographs taken from one P. ochraceus individual as it progressed through SSWD. Numbers in the top left corner of each picture relate to the P. ochraceus SSWD symptom guide from seastarwasting.org with the addition of category 5 for dead individuals. (B) Proportion of the 37 individuals of each symptom number at the six sampling time points.
	Figure 2. Differences in microbial community between sick and healthy individuals. Principal Coordinate Analysis plots of microbial communities from all samples throughout the experiment, excluding the 8 samples taken from individuals when dead. Samples that were taken from an individual that was sick at the time of sampling are colored purple while samples that were taken from an individual that was healthy at the time of sampling are colored orange. Principal Coordinate Analysis was based on the weighted UniFrac distance matrix. Ellipses are drawn around each group’s centroid (confidence interval, 0.95).
	Figure 3. Microbial community differences through SSWD symptom progression. (A) Proportions of OTUs classified to the Order level in microbial communities from sea stars sampled through disease stages. Disease stage number relates to the P. ochraceus SSWD symptom guide from seastarwasting.org with the addition of a category 5 for dead individuals. (B) Rarefaction plot of mean chao1 alpha diversity estimates as a function of sequencing depth for samples grouped by disease stage. Shaded areas represent the standard error of the mean (SEM) for the chao1 estimates.
	Figure 4. Changes in abundance of OTUs through SSWD progression. (A) Log normalized abundance of 6 OTUs whose abundance decreased from healthy samples through symptom progression. Abundance of these OTUs differed between healthy and early stage sick samples (adjusted P values presented from this test) and between healthy and late stage sick samples. (B) Log normalized abundance of 6 OTUs whose abundance increased from healthy samples through symptom progression. Abundance of these OTUs differed between healthy and early stage sick samples (adjusted P value presented from this test) and between healthy and late stage sick samples. The centerline of the boxplots represents the median of the data, the box represents the interquartile range, and the whiskers represent the minimum and maximum values.
	Figure 5. Venn diagram of differentially abundant OTUs between samples of different disease stages. ‘Early-stage disease’ includes symptom numbers 1 and 2 and ‘late-stage disease’ includes symptom numbers 3, 4, and 5.

References [+] :

Altschul, Basic local alignment search tool. 1990, Pubmed