Diversity of slime molds–much more than what meets the eye

DNA metabarcoding reveals diversity and composition of myxomycete communities in lowland pine forests of western Russia

Hemitrichia serpula
Pretzel slime mold (Hemitrichia serpula) by Alexander Shirokikh via iNaturalist. Photo licensed under CC BY-NC 4.0.

Myxomycetes–or slime molds–are fascinating lifeforms with a complex life cycle involving a single cell amoeba-like stage followed by multinuclear aggregates, culminating in a fruiting body-like structure with airborne spores restarting the cycle.

In a study of so-called dark-spored slime molds, researchers used DNA metabarcoding to assess the diversity of myxomycetes in the lowland pine forests of Nizhne-Svirskiy Reserve, Russia. Sampling both ground litter and soil in separate study plots representing four different stages after a forest fire, followed by DNA extraction, amplification and sequencing, the authors produced more than 300,000 sequence reads based on myxomycete-specific primers. These sequences clustered to less than 200 operational taxonomic units (OTU), of which the authors identified 15 species and 9 genera.

Comparing identified taxa against GBIF-mediated occurrences, the authors find four species new to the Leningrad region. While the myxomycete composition shifted significantly with the fire history of a plot, the authors were unable to find a clear chronosequence, suggesting that factors shaping assemblages aren't simply a linear product of time passed since a fire.

The study identifies DNA metabarcoding is a useful tool in describing slime mold diversity as invisible amoeba-stage populations are much more widespread than what is reported by recordings of visible fruiting bodies.

Link to original article

Shchepin ON, Schnittler M, Erastova DA, Prikhodko IS, Borg Dahl M, Azarov DV, Chernyaeva EN and Novozhilov YK (2019) Community of dark-spored myxomycetes in ground litter and soil of taiga forest (Nizhne-Svirskiy Reserve, Russia) revealed by DNA metabarcoding. Fungal Ecology. Elsevier BV 39: 80–93. Available at: https://doi.org/10.1016/j.funeco.2018.11.006.