The use of antibiotics is not permitted in Switzerland; moreover, no other medication exists to combat European foul brood. Hives with symptoms must therefore be destroyed in order to limit the outbreak, and the contaminated material must be sanitised. Since prevention is the best cure, early detection is desirable. Numerous studies have been undertaken and documents have been created at the Swiss Bee Research Centre and elsewhere to draw the attention of beekeepers to these problems and inform them about the causes and the control measures to be implemented.
Donhauser J., Briones M. J. I., Mikola J., Jones D. L., Eder R., Filser J., Frossard A., Krogh P. H., Sousa J. P., Cortet J., Desie E., Domene X., Djuric S., Hackenberger D., Jimenez J. J., Iamandei M., Rissmann C., Schmidt O., Shanskiy M., Silfver T., Vancampenhout K., Vasutova M., Velizarova E., Frey B.
Extracting DNA from soil or directly from isolated nematodes indicate dissimilar community structure for Europe-wide forest soils.
Nematodes are numerous in soils and play a crucial role in soil food-webs. DNA metabarcoding offers a time-effective alternative to morphology-based assessments of nematode diversity. However, it is unclear how different DNA extraction methods prior to metabarcoding could affect community analysis. We used soils with woody vegetation from a European latitudinal gradient (29 sites, 39 to 79°N, ∼4500 km, covering six biomes) to systematically evaluate the effect of two sources of nematode DNA either directly extracted from soils vs. extracted from nematodes previously isolated from soils hypothesizing that the DNA source material may produce different diversities, community structures and abundances of feeding types. Nematode-sample DNA exhibited a higher richness, while no difference in Shannon diversity was found between the approaches. The DNA sources also created significantly different community structures, with greater differences observed across soil-extracted DNA than nematode-sample DNA. The most overrepresented species in nematode-sample DNA were Heterocephalobus elongatus, Eucephalobus striatus and Hexatylus sp., whereas Phasmarhabditis sp. and Eumonhystera filiformis were overrepresented in soil-extracted DNA. Read abundances of feeding types significantly differed between the DNA sources and across sites, with a significant effect of biome on both ecto- and endoparasitic herbivores in soil-extracted DNA and for ectoparasitic herbivores only in nematode-sample DNA. Collectively, our data suggest that choice of the DNA source material may lead to different patterns of nematode community composition across space and environmental conditions. Improving the sensitivity of the soil-extracted DNA method by developing protocols using larger amounts of soil and designing nematode-specific primers will make this approach an efficient screening tool to analyse nematode diversity and community structure complementing the labour-intensive isolation of intact nematodes from soils (nematode-sample DNA).
