Meta-analysis of microbial communities among different marine hosts and locations Authors: Andrea Aldas-Vargas1, Georg Steinert1, Hauke Smidt1, Detmer Sipkema1 1Wageningen University, The Netherlands
[email protected]
Background
Results
Microbial communities are often dense and diverse in many marine invertebrates (Taylor et al., 2007). The oceans harbor >106 microbial cells per
Number of samples
ml (Madigan et al., 2015). Microbes are part of nutrient cycles which allows other forms of life on the seawater. Macroinvertebrates are one of the most
Sponges
202
important hosts for bacteria and archaea and those associations have shaped the evolutionary paths of both host and symbiont alike (Hunter-Cevera et al., 2005).
Corals
Alphaproteobacteria Flavobacteria Cyanobacteria
509 environmental samples 9.6 million bacterial V6-rRNA
135
Ascidians
65
0
50
100
150
200
250
Figure 4. The number of samples evaluated for this project. So far, samples were analysed from 27 studies, collected as part of the metadata collection phase. Gammaproteobacteria Deltaproteobacteria
Figure 1. Sequences from seafloor and seawater samples showed that the predominant communities differ among different environments (Zinger et al., 2011)
A
B
Zinger et al., 2011 demonstrated that pelagic and benthic communities differ remarkably as presented in Figure 1. However, it is still unclear if the observed patterns are also host and location specific. Additionally, the ecological coherence concerning the host-associated microorganisms at different taxonomic ranks have not been fully addressed. Nonetheless, it has been suggested that at deeper taxonomic levels, patterns tend to appear regarding the ecological preferences of microorganisms (Philippot et al., 2010).
Objective The symbiotic relationships between the microorganisms and macroinvertebrates are quite complex, consequently the general aim of this is to further investigate marine microbial communities across different hosts and locations. High-throughput-sequencing generated datasets will be
Figure 5. nMDS ordination plot (Bray-Curtis distance) of marine invertebrates at A) phylum and B) genus level. Function ordihull in vegan (Oksanen et al., 2012) was used to encircle the site according to the host. A) Stress value was overall 0.185. The number of samples were 402 and 62 phyla (variables) were found. B) Stress value was overall 0.165. The number of samples were 402 and 1380 genera (variables) were found.
analyzed to elucidate whether the distribution of microbial communities is dependent on the location and/or the hosts.
Take home messages
Methods
v Microbes are widely distributed among different marine hosts (Figure 4).
The identification of the different microorganisms in marine hosts can now be achieved by 16S rRNA gene amplicon sequencing. Figure 2 shows a
L K
Studies
J I
Mothur • OTU tables • Taxonomy classification
• Concatenation • Diversity and community analysis
Databases
A
B
taxonomic ranks (Figure 5AB). C
Abundance tables (OTUs)
H
G
D E F
v It is not fully elucidated yet if the clusters regarding each host are dependent on factors such as geographic location. v Further investigation is needed to shed light on the microbial habitat preferences.
R Collapsed Genus (A to L)
Figure 2. General methodology overview.
regions are used is possible after the individual processing of datasets. v The microbial distribution seems to be different when analysed at different
descriptive scheme of the methodology.
• Sequence information (raw data or demultiplexed)
v The combination of a broad set of studies where distinct 16S rRNA variable
Collapsed Family (A to L)
Collapsed Order (A to L)
Collapsed Class (A to L)
Collapsed Phylum (A to L)
Figure 3. Integration from different datasets to collapsed files.
Overcoming Methodological Challenges v The studies use different amplicons of the 16S rRNA. v Individual abundance tables were obtained. v Different taxonomic levels were evaluated on the collapsed files. A scheme on how the wide variety of studies were treated in order to evaluate a relevant number of datasets is presented in Figure 3.
References • Hunter-Cevera, J., Karl, D., & Buckley, M. (2005). Marine Microbial Diversity : the Key To Earth ’ S Habitability. American Academy of Microbiology. • Madigan, M., Martinko, J. M., Bender, K. S., Buckley, D. H., & Stahl, D. A. (2015). Brock: Biology of the Microorganisms. Journal of Chemical Information and Modeling (Vol. 53). http://doi.org/10.1017/CBO9781107415324.004 • Philippot, L., Andersson, S. G. E., Battin, T. J., Prosser, J. I., Schimel, J. P., Whitman, W. B., & Hallin, S. (2010). The ecological coherence of high bacterial taxonomic ranks. Nature Publishing Group, 8(7), 523–529. http://doi.org/10.1038/nrmicro2367 • Taylor, M. W., Radax, R., Stegar, D., & Wagner, M. (2007). Sponge-associated microorganisms: evolution, evology, and biotechnological potential. Microbiology and Molecular Biology Reviews, 71(2), 295–347. http://doi.org/10.1128/MMBR.00040-06 • Zinger, L., Amaral-Zettler, L. A., Fuhrman, J. A., Horner-Devine, M. C., Huse, S. M., Welch, D. B. M., Ramette, A. (2011). Global patterns of bacterial beta-diversity in seafloor and seawater ecosystems. PLoS ONE, 6(9), 1–11.
