PT  - JOURNAL ARTICLE
AU  - Robin-Tobias Jauss
AU  - Susanne Walden
AU  - Anna Maria Fiore-Donno
AU  - Stefan Schaffer
AU  - Ronny Wolf
AU  - Kai Feng
AU  - Michael Bonkowski
AU  - Martin Schlegel
TI  - A parasite’s paradise: Biotrophic species prevail oomycete community composition in tree canopies
AID  - 10.1101/2021.02.17.431613
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.02.17.431613
4099  - http://biorxiv.org/content/early/2021/02/17/2021.02.17.431613.short
4100  - http://biorxiv.org/content/early/2021/02/17/2021.02.17.431613.full
AB  - Oomycetes (Stramenopiles, Protista) are among the most severe plant pathogens, comprising species with a high economic and ecologic impact on forest ecosystems. Their diversity and community structures are well studied in terrestrial habitats, but tree canopies as huge and diverse habitats have been widely neglected. A recent study highlighted distinct oomycete communities in the canopy region compared to forest soils when taking oomycete abundances into account, in contrast to the homogeneity at the incidence level. It remains however unknown if this homogeneity also leads to a functional homogenisation among microhabitats. In this study, we supplemented functional traits to oomycete canopy and ground communities, which were determined over a time period of two years with a metabarcoding approach. Our results showed that even though most oomycetes occurred in all habitats, a strong discrepancy between the strata and correspondingly the distribution of oomycete lifestyles could be observed, which was constant over time. Obligate biotrophic species, exclusively feeding on living host tissue, dominated the canopy region, implying tree canopies to be a hitherto neglected reservoir for parasitic protists. Parasites highly specialised on hosts that were not sampled could be determined in high abundances in the canopy and the surrounding air, challenging the strict host dependencies ruled for some oomycetes. Our findings further contribute to the understanding of oomycete ecosystem functioning in forest ecosystems.Competing Interest StatementThe authors have declared no competing interest.