Temporal patterns of soil micro-eukaryotic diversity beneath decomposing pig cadavers as assessed by high throughput sequencing

Cadavers represent a natural perturbation that influences strongly the soil environment, but little is known about the impact on soil micro-eukaryotic (protists and fungi) communities. We assessed the impact of pig cadavers on soil communities in a mixed oak forest. We analysed the molecular diversity of soil micro-eukaryotes by Illumina sequencing of V9 region of the rDNA SSU gene. We then selected indicator OTUs responding positively (“cadaver lovers”) or negatively (“cadaver haters”) to the presence of cadavers using the Indicator Value (IndVal) approach. Cadaver decomposition caused a decrease in micro-eukaryotic diversity and profound changes in the structure of communities. “Cadaver lovers” included rarely reported taxa such as the cellular slime mould Fonticula alba and parasites of other protists such as basal Alveolates. Furthermore, approximately half of “Cadaver lovers” OTUs, despite having passed all quality check procedures had poor matches (< 80%) to any GenBank sequence. This illustrates that understudied habitats such as cadaver-impacted soils represent promising sites to uncover unknown soil micro-eukaryotic diversity. This study also illustrates the potential of high throughput sequencing of micro-Eukaryotes to develop novel forensic tools for inferring the origin of samples or estimating the time after death (post-mortem interval) of a cadaver.