Data from: Site specific distribution of oak rhizosphere associated oomycetes revealed by cytochrome c oxidase subunit II metabarcoding

The phylum Oomycota comprises important tree pathogens like Phytophthora
quercina, involved in central European oak decline, and P. cinnamomi shown
to affect holm oaks among many other hosts. Despite the importance to
study the distribution, dispersal and niche partitioning of this phylum,
metabarcoding surveys and studies considering environmental factors that
could explain oomycete community patterns are still rare. We investigated
oomycetes in the rhizosphere of evergreen oaks in a Spanish oak woodland
using metabarcoding based on Illumina sequencing of the taxonomic marker
cytochrome c oxidase subunit II (cox2). We developed an approach
amplifying a 333 bp long fragment using the forward primer Hud-F
(Hudspeth, Nadler, & Hudspeth, 2000) and a reverse primer found
using DegePrime (Hugerth et al., 2014). Factors reflecting topo-edaphic
conditions and tree health were linked to oomycete community patterns. The
majority of detected OTUs belonged to the Peronosporales. Most taxa were
relatives of the Pythiaceae, but relatives of the Peronosporaceae and
members of the Saprolegniales were also found. The most abundant OTUs were
related to Globisporangium irregulare and Phytophthora cinnamomi, both
displaying strong site specific patterns. Oomycete communities were
strongly correlated with the environmental factors: altitude, crown
foliation, slope and soil skeleton and soil nitrogen. Our findings
illustrate the significance of small scale variation in habitat conditions
for the distribution of oomycetes and highlights the importance to study
oomycete communities in relation to such ecological patterns.