Pasteuria_Nematode_Metabarcoding_Supporting_Data

<i>Pasteuria</i> spp. are endospore forming bacteria which act as natural antagonists to many of the most economically significant plant parasitic nematodes (PPNs). Highly species-specific nematode suppression may be observed in soils containing a sufficiently high density of <i>Pasteuria</i> spp. spores. This suppression is enacted by the bacteria <i>via</i> inhibition of root invasion and sterilization of the nematode host. Molecular methods for the detection of <i>Pasteuria</i> spp. from environmental DNA (eDNA) have been described; however, these methods are limited in both scale and in depth. We report the use of metabarcoding to profile <i>Pasteuria</i> spp. and nematode communities in parallel. We have investigated <i>Pasteuria</i> spp. population structure in Scottish soils using eDNA from two sources: soil extracted DNA from the second National Soil Inventory of Scotland (NSIS2); and nematode extracted DNA collected from farms in the East Scotland Farm Network (ESFN). We compared the <i>Pasteuria</i> spp. community culture to both nematode community structure and the physiochemical properties of soils. Our results indicate that <i>Pasteuria</i> spp. populations in Scottish soils are broadly dominated by two sequence variants. The first of these aligns with high identity to <i>Pasteuria</i> <i>hartismeri</i>, a species first described parasitizing <i>Meloidogyne</i> <i>ardenensis, </i>a nematode parasite of woody and perennial plants in northern Europe. The second aligns with a <i>Pasteuria</i>-like sequence which was first recovered from a farm near Edinburgh which was found to contain <i>Pratylenchus</i> spp. encumbered by <i>Pasteuria</i> spp. endospores. Further, soil carbon, moisture, bulk density, and pH showed a strong correlation with the <i>Pasteuria</i> spp. community composition. These results indicate that metabarcoding is appropriate for the sensitive, specific, and semi-quantitative profiling of <i>Pasteuria</i> species from eDNA.