Contrasting sensitivity of soil bacterial and fungal community composition to one year of water limitation in Scots pine mesocosms

• Published in: FEMS microbiology ecology Vol. 99; no. 6
• Main Authors: Jaeger, Astrid C H, Hartmann, Martin, Six, Johan, Solly, Emily F
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 31.05.2023
• Subjects: Bacteria; Carbon/nitrogen ratio; Community composition; Community involvement; Community structure; Composition; Desiccation; DNA barcoding; Drought; Fungi; Mesocosms; Microbial activity; Microbiomes; Microorganisms; Moisture content; Nutrient cycles; Pine; Pine trees; Pinus sylvestris; Seasonal variations; Soil chemistry; Soil microorganisms; Soil pH; Soil properties; Soil structure; Soil temperature; Soil water; Water content; Water deficit; Water resistance; mesocosm experiment; Scots Pine (Pinus Sylvestris L); water limitation; DNA metabarcoding; seasonality; soil microbiome; Scots Pine (Pinus Sylvestris L.)
• ISSN: 1574-6941; 0168-6496; 1574-6941
• DOI: 10.1093/femsec/fiad051

Abstract The soil microbiome is crucial for regulating biogeochemical processes and can, thus, strongly influence tree health, especially under stress conditions. However, little is known about the effect of prolonged water deficit on soil microbial communities during the development of saplings. We assessed the response of prokaryotic and fungal communities to different levels of experimental water limitation in mesocosms with Scots pine saplings. We combined analyses of physicochemical soil properties and tree growth with DNA metabarcoding of soil microbial communities throughout four seasons. Seasonal changes in soil temperature and soil water content and a decreasing soil pH strongly influenced the composition of microbial communities but not their total abundance. Contrasting levels of soil water contents gradually altered the soil microbial community structure over the four seasons. Results indicated that prokaryotic communities were less resistant to water limitation than fungal communities. Water limitation promoted the proliferation of desiccation tolerant, oligotrophic taxa. Moreover, water limitation and an associated increase in soil C/N ratio induced a shift in the potential lifestyle of taxa from symbiotic to saprotrophic. Overall, water limitation appeared to alter soil microbial communities involved in nutrient cycling, pointing to potential consequences for forest health affected by prolonged episodes of drought. Despite the influence of the sampling time point, water limitation altered soil microbial community structures in Scots pine mesocosms, but fungal taxa were less sensitive to reduced soil water contents.